The present invention is directed to novel substituted xcex1-hydroxy acid thereof, represented by the general Formula I:

1. Field of the Invention
This invention is in the field of medicinal chemistry. In particular, the invention relates to substituted xcex1-hydroxy acids that are inhibitors of caspases. The invention also relates to the use of these substituted xcex1-hydroxy acids for reducing or treating apoptotic cell death and/or reducing interleukin 1-xcex2 production.
2. Prior Art
Organisms eliminate unwanted cells by a process variously known as regulated cell death, programmed cell death or apoptosis. Such cell death occurs as a normal aspect of animal development as well as in tissue homeostasis and aging (Glucksmann, A., Biol. Rev. Cambridge Philos. Soc. 26:59-86 (1951); Glucksmann, A., Archives de Biologie 76:419-437 (1965); Ellis et al., Dev. 112:591-603 (1991); Vaux et al., Cell 76:777-779 (1994)). Apoptosis regulates cell number, facilitates morphogenesis, removes harmful or otherwise abnormal cells and eliminates cells that have already performed their function. Additionally, apoptosis occurs in response to various physiological stresses, such as hypoxia or ischemia (PCT published application WO96/20721).
There are a number of morphological changes shared by cells experiencing regulated cell death, including plasma and nuclear membrane blebbing, cell shrinkage (condensation of nucleoplasm and cytoplasm), organelle relocalization and compaction, chromatin condensation and production of apoptotic bodies (membrane enclosed particles containing intracellular material) (Orrenius, S., J. Internal Medicine 237:529-536 (1995)).
Apoptosis is achieved through an endogenous mechanism of cellular suicide (Wyllie, A. H., in Cell Death in Biology and Pathology, Bowen and Lockshin, eds., Chapman and Hall (1981), pp. 9-34). A cell activates its internally encoded suicide program as a result of either internal or external signals. The suicide program is executed through the activation of a carefully regulated genetic program (Wylie et al., Int. Rev. Cyt. 68:251 (1980); Ellis et al., Ann. Rev. Cell Bio. 7:663 (1991)). Apoptotic cells and bodies are usually recognized and cleared by neighboring cells or macrophages before lysis. Because of this clearance mechanism, inflammation is not induced despite the clearance of great numbers of cells (Orrenius, S., J. Internal Medicine 237:529-536 (1995)).
Mammalian interleukin-1xcex2 (IL-1xcex2) plays an important role in various pathologic processes, including chronic and acute inflammation and autoimmune diseases (Oppenheim, J. H. et. al. Immunology Today, 7, 45-56 (1986)). IL-1xcex2 is synthesized as a cell associated precursor polypeptide (pro-IL-1xcex2) that is unable to bind IL-1 receptors and is biologically inactive (Mosley et al., J. Biol. Chem. 262:2941-2944 (1987)). By inhibiting conversion of precursor IL-1xcex2 to mature IL-1xcex2, the activity of interleukin-1 can be inhibited. Interleukin-1xcex2 converting enzyme (ICE) is a protease responsible for the activation of interleukin-1xcex2 (IL-1xcex2) (Thornberry, N. A., et al., Nature 356:768 (1992); Yuan, J., et al., Cell 75:641 (1993)). ICE is a substrate-specific cysteine protease that cleaves the inactive prointerleukin-1 to produce the mature IL-1. The genes that encode for ICE and CPP32 are members of the mammalian ICE/Ced-3 family of genes which presently includes at least twelve members: ICE, CPP32/Yama/Apopain, mICE2, ICE4, ICH1, TX/ICH-2, MCH2, MCH3, MCH4, FLICE/MACH/MCH5, ICE-LAP6 and ICErelIII. The proteolytic activity of this family of cysteine proteases, whose active site (a cysteine residue) is essential for ICE-mediated apoptosis, appears critical in mediating cell death (Miura et al., Cell 75:653-660 (1993)). This gene family has recently been named caspases (Alnernri, E. S. et. al. Cell, 87, 171 (1996), and Thornberry, N. A. et. al. J. Biol. Chem. 272, 17907-17911 (1997)) and divided into three groups according to its known functions. Table 1 summarizes these known caspases.
IL-1 is also a cytokine involved in mediating a wide range of biological responses including inflammation, septic shock, wound healing, hematopoiesis and growth of certain leukemias (Dinarello, C. A., Blood 77:1627-1652 (1991); diGiovine et al., Immunology Today 11:13 (1990)).
Many potent caspase inhibitors have been prepared based on the peptide substrate structures of caspases. However, in contrast to their potency in vitro, there are few inhibitors with good efficacy (IC50 less than 1 xcexcM) in whole-cell models of apoptosis have been reported (Thornberry, N. A. Chem. Biol. 5:R97-103 (1998)). Therefore the need exists for cell death inhibitors that are efficacious in whole-cell models of apoptosis and active in animal model of apoptosis. These inhibitors thus can be employed as therapeutic agents to treat disease states in which regulated cell death and the cytokine activity of IL-1 play a role.
WO 93/05071 discloses peptide ICE inhibitors with the formula:
Zxe2x80x94Q2-Asp-Q1
wherein Z is an N-terminal protecting group; Q2 is 0 to 4 amino acids such that the sequence Q2-Asp corresponds to at least a portion of the sequence Ala-Tyr-Val-His-Asp (SEQ ID NO:2); and Q1 comprises an electronegative leaving group.
WO 96/03982 discloses aspartic acid analogs as ICE inhibitors with the formula:
wherein R2 is H or alkyl; R3 is a leaving group such as halogen; R1 is heteroaryl-CO or an amino acid residue.
U.S. Pat. No. 5,585,357 discloses peptidic ketones as ICE inhibitors with the formula:
wherein n is 0-2; each AA is independently L-valine or L-alanine; R1 is selected from the group consisting of N-benzyloxycarbonyl and other groups; R8, R9, R10 are each independently hydrogen, lower alkyl and other groups.
Mjalli et al. (Bioorg. Med. Chem. Lett., 3, 2689-2692, 1993) report the preparation of peptide phenylalkyl ketones as reversible inhibitors of ICE, such as:
Thornberry et al. (Biochemistry, 33, 3934-3940, 1994) report the irreversible inactivation of ICE by peptide acyloxymethyl ketones:
wherein Ar is COPh-2,6-(CF3)2, COPh-2,6-(CH3)2, Phxe2x80x94F5 and other groups.
Dolle et al. (J. Med. Chem. 37, 563-564, 1994) report the preparation of P1 aspartate-based peptide xcex1-((2,6-dichlorobenzoyl)oxy)methyl ketones as potent time-dependent inhibitors of ICE, such as:
Mjalli et al. (Bioorg. Med. Chem. Lett., 4, 1965-1968, 1994) report the preparation of activated ketones as potent reversible inhibitors of ICE:
wherein X is NH(CH2)2, OCO(CH2)2, S(CH2)3 and other groups.
Dolle et al. (J. Med. Chem. 37, 3863-3866, 1994) report the preparation of xcex1-((1-phenyl-3-(trifluoromethyl)-pyrazol-5-yl)oxy)methyl ketones as irreversible inhibitor of ICE, such as:
Mjalli et al. (Bioorg. Med. Chem. Lett., 5, 1405-1408, 1995) report inhibition of ICE by N-acyl-Aspartic acid ketones:
wherein XR2 is NH(CH2)2Ph, OCO(CH2)2cyclohexyl and other groups.
Mjalli et al. (Bioorg. Med. Chem. Lett., 5, 1409-1414, 1995) report inhibition of ICE by N-acyl-aspartyl aryloxymethyl ketones, such as:
Dolle et al. (J. Med. Chem. 38, 220-222, 1995) report the preparation of aspartyl xcex1-((diphenylphosphinyl)oxy)methyl ketones as irreversible inhibitors of ICE, such as:
Graybill et al. (Bioorg. Med. Chem. Lett., 7, 41-46, 1997) report the preparation of xcex1-((tetronoyl)oxy)- and xcex1-((tetramoyl)oxy)methyl ketones as inhibitors of ICE, such as:
Semple et al. (Bioorg. Med. Chem. Lett., 8, 959-964, 1998) report the preparation of peptidomimetic aminomethylene ketones as inhibitors of ICE, such as:
Okamoto et al. (Chem. Pharm. Bull. 47, 11-21, 1999) report the preparation of peptide based ICE inhibitors with the P1 carboxyl group converted to an amide, such as:
EP618223 patent application disclosed inhibitor of ICE as anti-inflammatory agents:
Rxe2x80x94A1xe2x80x94A2xe2x80x94Xxe2x80x94A3
Wherein R is a protecting group or optionally substituted benzyloxy; A1 is an xcex1-hydroxy or xcex1-amino acid residue or a radical of formula:
wherein ring A is optionally substituted by hydroxy or C1-4 alkoxy and Ra is CO or CS; A2 is an xcex1-hydroxy or xcex1-amino acid residue or A1 and A2 form together a pseudo-dipeptide or a dipeptide mimetic residue; X is a residue derived from Asp; A3 is xe2x80x94CH2xe2x80x94X1xe2x80x94COxe2x80x94Y1, xe2x80x94CH2xe2x80x94Oxe2x80x94Y2, xe2x80x94CH2xe2x80x94Sxe2x80x94Y3, wherein X1 is O or S; Y1, Y2 or Y3 is cycloaliphatic residue, and optionally substituted aryl.
WO99/18781 discloses dipeptides of formula:
wherein R1 is an N-terminal protecting group; AA is a residue of any natural or non-natural xcex1-amino acid, xcex2-amino acid, derivatives of an xcex1-amino acid or xcex2-amino acid; R2 is H or CH2R4 where R4 is an electronegative leaving group, and R3 is alkyl or H, provided that AA is not His, Tyr, Pro or Phe. These dipeptides are surprisingly potent caspase inhibitors of apoptosis in cell based systems. These compounds are systemically active in vivo and are potent inhibitors of antiFas-induced lethality in a mouse liver apoptosis model and have robust neuroprotective effects in a rat model of ischemic stroke.
WO 99/47154 discloses dipeptides of formula:
wherein R1 is an N-terminal protecting group; AA is a residue of a non-natural xcex1-amino acid or xcex2-amino acid; R2 is an optionally substituted alkyl or H.
WO 00/01666 discloses c-terminal modified oxamyl dipeptides as inhibitors of the ICE/ced-3 family of cysteine proteases:
wherein A is a natural or unnatural amino acid; B is a hydrogen atom, a deuterium atom, alkyl, cycloalkyl and other groups; R1 is alkyl, cycloalkyl and other groups, R2 is hydrogen, lower alkyl and other groups.
WO 00/23421 discloses (substituted)acyl dipeptidyl inhibitors of the ICE/ced-3 family of cysteine proteases:
wherein A is a natural or unnatural amino acid; B is a hydrogen atom, a deuterium atom, alkyl, cycloalkyl and other groups; X is CH2, Cxe2x95x90O, O, S, NH, Cxe2x95x90ONH or CH2OCxe2x95x90ONH; n is 0, 1, or 2; q is 1 or 2; R1 is optionally substituted aryl and heteroaryl; R2 is hydrogen, alkyl and other groups; R3 is hydrogen, alkyl and other groups.
WO 00/32620 discloses gamma-ketoacid tetrapeptides as inhibitors of the caspase-3:
wherein R is H and COR1; R1 is hydrogen, alkoxy and other groups; R2 is hydrogen, CH3 and other groups; R3 is hydrogen, CH3 and other groups; R4 is hydrogen, CH3 and other groups; R5 is C1-6alkyl, arylC1-6alkyl and other groups; X2, X3 and X4 are independently H or X2 and R2, X3 and R3 or X4 and R4 may together form a saturated monocyclic ring.
The invention relates to compound of Formula I:
or pharmaceutically acceptable salts or prodrugs thereof, wherein
R1 is an optionally substituted alkyl or hydrogen;
R2 is hydrogen or optionally substituted alkyl;
R3 and R4 independently are hydrogen, optionally substituted aryl, optionally substituted heterocyclic, optionally substituted carbocyclic, optionally substituted heteroaryl, optionally substituted alkyl, optionally substituted alkenyl, or optionally substituted alkynyl;
R5 is optionally substituted alkyl, optionally substituted carbocyclic, optionally substituted heterocyclic, optionally substituted aryl or optionally substituted heteroaryl;
Z is O, S, NR8, or (CR9R10)n, where R8, R8 and R10 independently are hydrogen, alkyl or cycloalkyl, and n is 0, 1, 2, or 3; and
X is a peptide of 1-2 amino acids or a bond.
The present invention provides pharmaceutical compositions comprising a compound of Formula I in an effective amount to reduce apoptotic cell death in an animal.
The invention relates to the discovery that the compounds represented by Formula I are inhibitors of caspases. The invention also relates to the use of the compounds of the invention for reducing, preventing or treating maladies in which apoptotic cell death is either a causative factor or a result. Examples of uses for the present invention include treating or ameliorating cell death in the central or peripheral nervous system, retinal neurons, cardiac muscle or immune system cells of an animal; treating or preventing polycystic kidney disease, renal amyloidosis, acute renal failure, cyclosporine A induced murin tubular epithelial cell death, HIV-induced nephropathy or anemia/erythropoiesis in an animal; protecting a mammalian organ or tissue from cell death due to deprivation of normal blood supply; reducing or preventing cell death in a donor organ or tissue after it has been transplanted into a host due to the effects of host immune cells; reducing or preventing the death of mammalian sperm or eggs used in in vitro fertilization procedures; extending the lifespan of a mammalian or yeast cell line; treating or ameliorating hair loss or premature graying of the hair in a mammal; treating or ameliorating skin damage of a mammal due to exposure to high levels of radiation, heat or chemicals; treating or ameliorating sepsis in an animal; treating or ameliorating hepatitis in an animal; treating or ameliorating hereditary tyrosinemia type 1 in an animal; treating or ameliorating chronic alcohol ingestion induced buccal mucosa cell death in an animal; treating or ameliorating cell death in plants or flowers; treating or ameliorating radiation or ultraviolet-irradiation induced cell death in an animal; treating or ameliorating apoptotic death of bone marrow cells in myelodysplastic syndromes (MDS); treating or ameliorating apoptotic cell death in acute pancreatitis; treating or preventing the inflammatory response in psoriasis or inflammatory bowel disease; treating or ameliorating organ apoptosis after burn injury; treating or ameliorating small bowel tissue injury after intestinal ischemia-reperfusion; and treating, ameliorating or preventing oral mucositis, gastrointestinal mucositis, bladder mucositis, proctitis, bone marrow cell death, skin cell death or hair loss resulting from chemotherapy or radiation therapy of cancer in an animal
The inhibitors of caspases and apoptotic cell death of the present invention are compounds having the general Formula I:
or pharmaceutically acceptable salts or prodrugs thereof, wherein
R1 is an optionally substituted alkyl or hydrogen;
R2 is hydrogen or optionally substituted alkyl;
R3 and R4 independently are hydrogen, optionally substituted aryl, optionally substituted heterocyclic, optionally substituted carbocyclic, optionally substituted heteroaryl, optionally substituted alkyl, optionally substituted alkenyl, or optionally substituted alkynyl;
R5 is an optionally substituted alkyl, optionally substituted carbocyclic, optionally substituted heterocyclic, optionally substituted aryl or optionally substituted heteroaryl;
Z is O, S, NR8, or (CR9R10)n, where R8, R9 and R10 independently are hydrogen, alkyl or cycloalkyl, and n is 0, 1, 2, or 3; and
X is a peptide of 1-2 amino acids or a bond. Where X is one amino acid, it may be any one of the common 20 amino acids e.g., Ala, Val, Leu, Ile, Pro, Phe, Trp, Met, Gly, Ser, Thr, Cys, Tyr, Asp, Asn, Glu, Asn, Lys, Arg and His. Where X is a peptide, it may be Asp-Glu, Asp-Ala, Asp-Phe, Val-Glu, Leu-Glu, Thr-Glu, Ile-Glu, Tyr-Glu, and Trp-Glu.
With respect to R1, preferred alkyl groups are C1-6 alkyl groups, e.g. methyl, ethyl, propyl, isopropyl, isobutyl, pentyl and hexyl groups; and substituted C1-6alkyl groups, e.g. CH2O CH3 and CH2OCOCH3 (AM).
Preferred R2 are alkyl group substituted by electronegative group or leaving group, including fluoromethyl, chloromethyl, alkoxymethyl, aryloxymethyl, heteroaryloxymethyl, alkylthiomethyl, arylthiomethyl, aminomethyl, acyloxymethyl, and arylacyloxymethyl. Other examples of optional substituents that may be present at the R2 alkyl group include, without limitation, 3-pyrazolyloxy optionally substituted at the 2, 4 and 5-positions with lower alkyl; 3-(1-phenyl-3-trifluoromethyl)pyrazolyloxy; 2,6-di(trifluoromethyl)benzoyloxy; 2,6-dimethylbenzoyloxy, pentafluoro-phenoxy; 2,6-dichlorobenzoyloxy; 2-(3-(2-imidazolyl)naphthyl)oxy; diphenylphosphinyloxy; tetronyloxy; and tetramoyloxy.
With respect to R3 and R4, preferred groups are those that will match the side chain of natural amino acids or non-natural amino acids. In one embodiment, preferred R3 is hydrogen, preferred R4 is straight-chained or branched C1-6 alkyl including methyl, ethyl, isopropyl and isobutyl; or preferred R4 is cycloalkyl, aryl or heteroaryl; or preferred R4 is straight-chained or branched C1-6 alkyl optionally substituted by one or more hydroxy, halogen, carboxy, amino, amide, ester, guanadino, thiol, alkylthiol, aryl, heterocyclic or heteroaryl groups.
With respect to R5, preferred alkyl are methyl, ethyl, isopropyl, isobutyl; preferred substituents on alkyl are hydroxy, carboxy, halogen, C4-C7 cycloalkyl, saturated and unsaturated heterocyclic, aryl or heteroaryl; preferred cycloalkyl are cyclopentyl and cyclohexyl; preferred saturated and unsaturated heterocyclic groups are piperidinyl and morpholinyl; preferred aryls are phenyl and naphthyl; preferred heteroaryls are pyridyl, indolyl, furyl and thienyl; preferred substituents on the aryl and heteroaryl are methyl, ethyl, chloro, fluoro, bromo, trifluoromethyl, methoxy, hydroxy, carboxy, cyano and nitro. Especially preferred R5 is optionally substituted phenyl, naphthyl, heteroaryl, or benzyl. Preferred Z is O, NH, or CH2.
The invention relates to the discovery that the compounds represented by Formula I are inhibitors of caspases. These inhibitors slow or block cell death in a variety of clinical conditions and industrial applications in which the loss of cells, tissues or entire organs occurs. Therefore, the invention is also related to methods of treating, preventing or reducing conditions in which apoptosis plays a role. These conditions are more fully described below.
The methods comprise administering to an animal in need of such treatment an inhibitor of the present invention, or a pharmaceutically acceptable salt or prodrug thereof, in an amount effective to inhibit apoptotic cell death.
Preferred embodiments of the compounds of Formula I that may be employed as inhibitors of caspases are represented by Formula II:
or pharmaceutically acceptable salts or prodrugs thereof wherein R1-R4 are as defined previously with respect to Formula I. R6 and R7 independently are hydrogen, alkyl, optionally substituted alkyl, C4-C7 cycloalkyl, saturated or unsaturated heterocyclic, aryl, heteroaryl, or R6 and R7 are combined together with the nitrogen to form a heterocycle.
Preferred R1 is H, Me, Et, t-Bu or AM. Preferred R2 is fluoromethyl, acyloxymethyl, arylacyloxymethyl, aryloxymethyl, heteroaryloxymethyl and aminomethyl. With respect to R6 and R7, preferred alkyl are methyl, ethyl, isopropyl, isobutyl; preferred substituents on alkyl are hydroxy, carboxy, carbamyl, carboxy ester, halogen, C4-C7 cycloalkyl, saturated and unsaturated heterocyclic, aryl or heteroaryl; preferred cycloalkyl are cyclopentyl and cyclohexyl; preferred saturated and unsaturated heterocyclic groups are piperidinyl and morpholinyl; preferred aryls are phenyl and naphthyl; preferred heteroaryls are pyridyl, indolyl, furyl and thienyl; preferred substituents on the aryl and heteroaryl are methyl, ethyl, chloro, fluoro, bromo, trifluoromethyl, methoxy, hydroxy, carboxy, cyano and nitro. Preferred heterocycles from combination of R6 and R7 together with the nitrogen are piperidine, mopholine, and piperazine.
With respect to R3 and R4, preferred R3 is hydrogen, and preferred R4 are those that will match the side chain of natural amino acids or non-natural amino acids. Specifically, preferred R3 and R4, together with the attached carbon, oxygen and carbonyl group are a residue of an xcex1-hydroxy acid. These xcex1-hydroxy acids include, but are not limited to 3-methoxymandelic acid, 4-methoxymandelic acid, 2-methoxymandelic acid, 4-bromomandelic acid, 4-methylmandelic acid, 2,5-dimethylmandelic acid, 4-methylthiomandelic acid, 4-chloromandelic acid, 3-chloromandelic acid, 2-chloromandelic acid, 4-fluoromandelic acid, 2,3-difluoromandelic acid, 2,4-difluoromandelic acid, 2,5-difluoromandelic acid, 3,5-difluoromandelic acid, 3,4-difluoromandelic acid, 2,6-difluoromandelic acid, 2,3,5-trifluoromandelic acid, 2,3,6-trifluoromandelic acid, 3,4-methylenedioxymandelic acid, 4-trifluoromethylmandelic acid, 3-nitromandelic acid, 4-nitromandelic acid, mandelic acid, hexahydromandelic acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-4-phenylbutyric acid, 2-hydroxybutyric acid, 2-hydroxybutynoic acid, 2-hydroxy-4-(methylthio)butyric acid, 2-hydroxy-3-butenoic acid, 2-hydroxy-3-methylpentanoic acid, 2-hydroxy-4-methylpentanoic acid, 3-phenyllactic acid, lactic acid, 3-chlorolactic acid, 3-imidazolelactic acid, 3,3,3-trifluorolactic acid, 3,3-difluoro-3-(4-fluorophenyl)lactic acid, 3,3-difluoro-3-(4-methoxyphenyl)lactic acid, 3,3-difluoro-3-(4-chlorophenyl)lactic acid, 3,3-difluoro-3-phenyllactic acid, 3-(1-naphthoxy)lactic acid, leucic acid, glycolic acid, 2-hydroxycaproic acid, 2-hydroxyvaleric acid, 2-hydroxyoctanoic acid, and indole-3-lactic acid. These xcex1-hydroxy acids are commercial available from Aldrich, Sigma, Lancaster, Maybridge and other companies.
Exemplary preferred inhibitors of caspases having Formular I and II include, without limitation:
1-(Carbonyl-Asp-CH2F)ethyl N-phenylcarbamate,
1-(Carbonyl-Asp-CH2F)ethyl N-benzylcarbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)propyl N-phenylcarbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)propyl N-benzylcarbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)propyl N-(2,6-dichlorophenyl)carbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)propyl N-(2,5-dichlorophenyl)-carbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)propyl N-(2,4-dichlorophenyl)-carbamate,
2-Methyl-1-(carbonyl-Asp-CH2DCB)propyl N-phenylcarbamate,
2-Methyl-1-(carbonyl-Asp-CH2DCB)propyl N-(2,6-dichlorophenyl)-carbamate,
2-Methyl-1-(carbonyl-Asp-CH2PTP)propyl N-phenylcarbamate,
2-Methyl-1-(carbonyl-Asp-CH2PTP)propyl N-(2,6-dichlorophenyl)-carbamate,
2-Methyl-1-(carbonyl-Asp-CH2DPP)propyl N-phenylcarbamate,
2-Methyl-1-(carbonyl-Asp-CH2DPP)propylN-(2,6-dichlorophenyl)-carbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)propyl N-(2-methyl-1-methoxycarbonyl-propyl)carbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)propyl N-(3-fluorophenyl)carbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)propyl N-(4-fluorophenyl)carbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)propyl N-(3,4-difluorophenyl)carbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)propyl N-(4-phenoxyphenyl)carbamate,
1-(Carbonyl-Asp-CH2F)propyl N-phenylcarbamate,
1-(Carbonyl-Asp-CH2F)butyl N-phenylcarbamate,
1-(Carbonyl-Asp-CH2F)-2-propenyl N-phenylcarbamate,
2-(4-Imidazolyl)-1-(carbonyl-Asp-CH2F)ethyl N-phenylcarbamate,
2-Phenyl-1-(carbonyl-Asp-CH2F)ethyl N-phenylcarbamate,
2-Methyl-1-(carbonyl-Asp-CH2F)butyl N-phenylcarbamate,
3-Methyl-1-(carbonyl-Asp-CH2F)butyl N-phenylcarbamate,
1-Phenyl-1-(carbonyl-Asp-CH2F)methyl N-phenylcarbamate,
1-(2-Chlorophenyl)-1-(carbonyl-Asp-CH2F)methyl N-phenylcarbamate,
1-(4-Chlorophenyl)-1-(carbonyl-Asp-CH2F)methyl N-phenylcarbamate,
1-Cyclohexyl-1-(carbonyl-Asp-CH2F)methyl N-phenylcarbamate,
2-Chloro-1-(carbonyl-Asp-CH2F)ethyl N-phenylcarbamate,
2,2,2-Trifluoro-1-(carbonyl-Asp-CH2F)ethyl N-phenylcarbamate, and
Z-Valine 2-methyl-1-(carbonyl-Asp-CH2F)propyl ester.
where Z is benzyloxycarbonyl, DPP is diphenylphosphinyloxy, PTP is 1-phenyl-3-(trifluoromethyl)pyrazol-5-yloxy and DCB is 2,6-dichlorobenzoyloxy.
Useful aryl groups are C6-14 aryl, especially C6-10 aryl. Typical C6-14 aryl groups include phenyl, naphthyl, phenanthrenyl, anthracenyl, indenyl, azulenyl, biphenyl, biphenylenyl and fluorenyl groups.
Useful cycloalkyl groups are C3-8 cycloalkyl. Typical cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl.
Useful saturated or partially saturated carbocyclic groups are cycloalkyl groups as defined above, as well as cycloalkenyl groups, such as cyclopentenyl, cycloheptenyl and cyclooctenyl.
Useful halo or halogen groups include fluorine, chlorine, bromine and iodine.
Useful alkyl groups include straight-chained and branched C1-10 alkyl groups, more preferably C1-6 alkyl groups. Typical C1-10 alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, 3-pentyl, hexyl and octyl groups. Also contemplated is a trimethylene group substituted on two adjoining positions on the benzene ring of the compounds of the invention.
Useful alkenyl groups include straight chained and branched C2-10 alkenyl groups, more preferably C2-6 alkenyl groups. Typical C2-10 alkenyl groups include ethenyl, propenyl, isopropenyl, butenyl, pentenyl, hexenyl and octenyl groups.
Useful alkynyl groups include straight chained and branched C2-10 alkynyl groups, more preferably C2-6 alkynyl groups. Typical C2-10 alkynyl groups include ethynyl, propynyl, butynyl, pentynyl, hexynyl and octynyl groups.
Useful arylalkyl groups include any of the above-mentioned C1-10 alkyl groups substituted by any of the above-mentioned C6-14 aryl groups. Useful values include benzyl, phenethyl and naphthylmethyl.
Useful haloalkyl groups include C1-10 alkyl groups substituted by one or more fluorine, chlorine, bromine or iodine atoms, e.g. fluoromethyl, difluoromethyl, trifluoromethyl, pentafluoroethyl, 1,1-difluoroethyl, chloromethyl, chlorofluoromethyl and trichloromethyl groups.
Useful alkoxy groups include oxygen substituted by one of the C1-10 alkyl groups mentioned above.
Useful alkylthio groups include sulphur substituted by one of the C1-10 alkyl groups mentioned above. Also included are the sulfoxides and sulfones of such alkylthio groups.
Useful acylamino groups are any C1-6 acyl (alkanoyl) attached to an amino nitrogen. e.g. acetamido, propionamido, butanoylamido, pentanoylamido, hexanoylamido as well as aryl-substituted C2-6 substituted acyl groups.
Useful acyloxy groups are any C1-6 acyl (alkanoyl) attached to an oxy (xe2x80x94Oxe2x80x94) group, e.g. formyloxy, acetoxy, propionoyloxy, butanoyloxy, pentanoyloxy, hexanoyloxy and the like.
Useful arylacyloxy groups include any of the aryl groups mentioned above substituted on any of the acyloxy groups mentioned above, e.g. 2,6-dichlorobenzoyloxy. 2,6-difluorobenzoyloxy and 2,6-di-(trifluoromethyl)-benzoyloxy groups.
Useful amino groups include xe2x80x94NH2, xe2x80x94NHR11, and xe2x80x94NR11R12, wherein R11 and R12 are C1-10 alkyl or cycloalkyl groups as defined above.
Useful saturated or partially saturated heterocyclic groups include tetrahydrofuranyl, pyranyl, piperidinyl, piperizinyl, pyrrolidinyl, irnidazolidinyl, imidazolinyl, indolinyl, isoindolinyl, quinuclidinyl, morpholinyl, isochromanyl, chromanyl, pyrazolidinyl pyrazolinyl, tetronoyl and tetramoyl groups.
Useful heteroaryl groups include any one of the following: thienyl, benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, furyl, pyranyl, isobenzofuranyl, chromenyl, xanthenyl, phenoxanthiinyl, 2H-pyrrolyl, pyrrolyl, imidazolyl, pyrazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, 3H-indolyl, indolyl, indazolyl, purinyl, 4H-quinolizinyl, isoquinolyl, quinolyl, phthalzinyl, naphthyridinyl, quinozalinyl, cinnolinyl, pteridinyl, carbazolyl, xcex2-carbolinyl, phenanthridinyl, acrindinyl, perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl, phenoxazinyl, 1,4-dihydroquinoxaline-2,3-dione, 7-aminoisocoumarin, pyrido[1,2-a]pyrimidin-4-one, 1,2-benzoisoxazol-3-yl, benzimidazolyl, 2-oxindolyl and 2-oxobenzimidazolyl. Where the heteroaryl group contains a nitrogen atom in a ring, such nitrogen atom may be in the form of an N-oxide, e.g. a pyridyl N-oxide, pyrazinyl N-oxide, pyrimidinyl N-oxide and the like.
Optional substituents include one or more alkyl; halo; haloalkyl; cycloalkyl; aryl optionally substituted with one or more lower alkyl, halo, haloalkyl or heteroaryl groups; aryloxy optionally substituted with one or more lower alkyl, halo, haloalkyl or heteroaryl groups; aralkyl; heteroaryl optionally substitued with one or more lower alkyl, haloalkyl and aryl groups; heteroaryloxy optionally substitued with one or more lower alkyl, haloalkyl and aryl groups; alkoxy; alkylthio; arylthio; amino; acyloxy; arylacyloxy optionally substitued with one or more lower alkyl, halo alkyl and aryl groups; diphenylphosphinyloxy optionally substituted with one or more lower alkyl, halo or haloalkyl groups; heterocyclo optionally substitued with one or more lower alkyl, haloalkyl and aryl groups; heterocycloalkyloxy optionally substitued with one or more lower alkyl, haloalkyl and aryl groups; partially unsaturated heterocycloalkyl optionally substitued with one or more lower alkyl, haloalkyl and aryl groups; or partially unsaturated heterocycloalkyloxy optionally substitued with one or more lower alkyl, haloalkyl and aryl groups.
Certain of the compounds of the present invention may exist as stereoisomers including optical isomers. The invention includes all stereoisomers and both the racemic mixtures of such stereoisomers as well as the individual enantiomers that may be separated according to methods that are well known to those of ordinary skill in the art.
Examples of pharmaceutically acceptable addition salts include inorganic and organic acid addition salts such as hydrochloride, hydrobromide, phosphate, sulphate, citrate, lactate, tartrate, maleate, fumarate, mandelate and oxalate; and inorganic and organic base addition salts with bases such as sodium hydroxy and Tris(hydroxymethyl)aminomethane (TRIS, tromethane).
Examples of prodrugs include compounds of Formulae I-II wherein R1 is an alkyl group or substituted alkyl group such as CH2OCH3 and CH2OCOCH3 (AM ester).
The invention is also directed to a method for treating disorders responsive to the inhibition of caspases in animals suffering thereof. Particular preferred embodiments of compounds for use in the method of this invention are represented by previously defined Formulae I-II.
The compounds of this invention may be prepared using methods known to those skilled in the art. Specifically, compounds of Formulae I-II with a fluoromethyl (CH2F) group can be prepared as illustrated by exemplary reactions in Scheme 1. Reaction of hydroxy acid with phenyl isocyanate gave the carbamate protected acid. Coupling of the acid with the intermediate hydroxy amine (Revesz et al., Tetrahedron Lett. 35:9693-9696 (1994)) produced the amide. Oxidation of the hydroxy group by Dess-Martin reagent according to Revesz et al. (Tetrahedron Lett. 35:9693-9696 (1994)) gave the ketone as a mixture of diasteriomers. Other oxidation reagents can be used in place of Dess-Martin reagent include pyridinium chlorochromate (PCC). TFA catalyzed cleavage of the t-Bu ester produced the acid.
Compounds of Formulae I-II with a dichlorobenzoyloxy (DCB) group can be prepared as illustrated by exemplary reactions in Scheme 2. Reaction of the bromomethylketone with dichlorobenzoic acid gave the ester. The Z protecting group was removed by hydrogenation to give the amine, which was coupled with the acid to produce the amide. The t-Bu ester was cleaved by TFA to give the acid.
Similarly, compounds of Formulae I-II with a 1-phenyl-3-(trifluoromethyl)pyrazol-5-yloxy (PTP) and a diphenylphosphinyloxy (DPP) group can be prepared as illustrated by exemplary reactions in Scheme 3 and 4, respectively.
An important aspect of the present invention is the discovery that compounds having Formulae I-II are inhibitors of caspases. Therefore, these inhibitors are expected to slow or block cell death in a variety of clinical conditions in which the loss of cells, tissues or entire organs occurs.
The cell death inhibitors of the present invention can be used to reduce or prevent cell death in the nervous system (brain, spinal cord, and peripheral nervous system) under various conditions of ischemia and excitotoxicity, including, but not limited to, focal ischemia due to stroke and global ischemia due to cardiac arrest, as well as spinal cord injury (Emery et al., J. Neurosurgery 89:911-920 (1998) and Springer et al., Nat Med. 5:943-946 (1999)). One particular usage is to treat the effects of oxygen deprivation which can occur during the birth of infants in high-risk labors or drowning. The cell death inhibitors can also be used to reduce or prevent cell death in the nervous system due to traumatic injury (such as head trauma), viral infection or radiation-induced nerve cell death (for example, as a side-effect of cancer radiotherapy). The cell death inhibitors can also be used to reduce or prevent cell death in a range of neurodegenerative disorders, including but not limited to Alzheimer""s disease (Mattson et al., Brain Res. 807:167-176 (1998)), Huntington""s Disease, Parkinson""s Disease, a prion disease, multiple sclerosis, amyotrophic lateral sclerosis, and spinobulbar atrophy. The in vivo neuroprotective properties of cell death inhibitors of the invention can be tested in a rat transient focal brain ischemia model (Xue et al., Stroke 21:166 (1990)).
The cell death inhibitors can also be used to treat or ameliorate cell death in the central or peripheral nervous system due to acute bacterial meningitis.
The cell death inhibitors of the invention can be used to reduce or prevent cell death in any conditions which potentially results in the death of cardiac muscle (Black et al., J. Mol. Cel. Card. 30:733-742 (1998) and Maulik et al., Free Radic. Biol. Med. 24:869-875 (1998)). This includes myocardial infarction due to myocardial ischemia and reperfusion, congestive heart failure and cardiomyopathy. One particular application is to reduce or prevent myocardial cell death as occurs in certain viral infections of the heart.
The in vivo activity of the cell death inhibitors of the invention can be tested using the xe2x80x9cmouse liver apoptosisxe2x80x9d model described by Rodriguez et al. (Rodriguez et al., J. Exp. Med. 184:2067-2072 (1996)). In this model, mice are treated intravenously (IV) with an antiFas antibody which induces massive apoptosis in the liver and other organs, leading to generalized organ failure and death. This model is useful for indirectly testing the systemic bioavailability of the cell death inhibitors of the invention, as well as their in vivo anti-apoptotic properties. The cell death inhibitors of the invention therefore can be used to reduce or prevent apoptosis of liver cells (Jones et al., Hepatology 27:1632-1642 (1998)) such as in sepsis (Jaeschke et al., J. Immunol. 160:3480-3486 (1998)) and hereditary tyrosinemia type 1 (HT1) (Kubo et al., Proc. Natl. Acad. Sci. USA 95:9552-9557 (1998)). The cell death inhibitors of the invention also can be used to treat hepatitis (Suzuki, Proc. Soc. Exp. Biol. Med. 217:450-454 (1998)).
The cell death inhibitors of the invention can be used to reduce or prevent cell death of retinal neurons (Kermer et al., J. Neurosci. 18:4656-4662 (1998) and Miller et al., Am. J. Vet. Res. 59:149-152 (1998)) as can occur in disorders which increase intraocular pressure (such as glaucoma) or retinal disorders associated with the aging process (such as age-related macular degeneration). The inhibitors can also be used to treat hereditary degenerative disorders of the retina, such as retinitis pigmentosa.
The cell death inhibitors of the invention can also be used to reduce or prevent cell death in the kidney. This includes renal amyloidosis (Hiraoka et al., Nippon Jinzo Gakkai Shi 40:276-83 (1998)), acute renal failure (Lieberthal et al. Semin Nephrol. 18:505-518 (1998)), murine tubular epithelial cell death induced by cyclosporine A (Ortiz et al. Kidney International Supp. 68:S25-S29 (1998)) and HIV-induced nephropathy (Conaldi et al. J. Clin. Invest. 102:2041-2049 (1998)).
The cell death inhibitors of the invention can also be used to reduce or prevent cell death of buccal mucosa due to chronic alcohol ingestion (Slomiany et al., Biochem. Mol. Biol. Int. 45:1199-1209 (1998)).
The cell death inhibitors of the invention can also be used to reduce or prevent apoptotic cell death in acute pancreatitis (Iovanna, Int. J. Pancreatol. 20:77-84 (1996) and Sata et al., Pancreas 19:76-82 (1999)).
The cell death inhibitors of the invention can also be used to reduce or prevent cell death in plants (Richberg et al., Curr. Opin. Plant Biol. 1:480-485 (1998)), such as plant cell death due to pathogens (Pozo et al., Curr. Biol. 8:1129-1132 (1998) and Greenberg et al., Cell, 77:551-563 (1994)).
The cell death inhibitors of the invention can also be used to reduce or prevent cell death due to radiation and ultraviolet-irradiation (Sheikh et al., Oncogene 17:2555-2563 (1998)).
The cell death inhibitors of the invention can also be used to reduce or prevent apoptotic death of bone marrow cells in myelodysplastic syndromes (MDS) (Mundle et al., Am. J. Hematol. 60:36-47 (1999)).
The cell death inhibitors of the invention can also be used to reduce or prevent organ apoptosis, such in thymus and spleen, in the early period after burn injury (Fukuzuka et al., Ann. Surg. 229:851-858 (1999)).
The cell death inhibitors of the invention can also be used to reduce or prevent premature death of cells of the immune system, and are particularly useful in treating immune deficiency disorders, such as acquired immune deficiency syndrome (AIDS), severe combined immune deficiency syndrome (SCIDS) and related diseases. The cell death inhibitors can also be used to treat radiation-induced immune suppression.
The cell death inhibitors can also be used to treat or ameliorate an autoimmune disorder including lupus erythematosus, rheumatoid arthritis and type I diabetes.
Transplantation of human organs and tissues is a common treatment for organ failure. However, during the transplantation process, the donor organ or tissue is at risk for cell death since it is deprived of its normal blood supply prior to being implanted in the host. This ischemic state can be treated with cell death inhibitors by infusion into the donor organ or tissue, or by direct addition of the cell death inhibitors to the organ/tissue storage medium, i.e. bathing the organ or tissue in the storage medium containg the compound prior to transplant of the organ or tissue into a mammal. Cell death inhibitors may also be administered to animals to reduce or prevent cell death in the donor organ/tissue after it has been transplanted to protect it from the effects of host immune cells which kill their targets by triggering apoptosis. Examples of such organs and tissues include without limitation kidneys, livers, hearts, pancreases, lungs, corneas, hands, and embryonic nigral tissue.
The cytoprotective effects of cell death inhibitors can also be used to prevent the death of human or animal sperm and eggs used in in vitro fertilization procedures. These inhibitors can be used during the harvesting process and can also be included in the storage medium.
Mammalian cell lines, insect cells and yeast cells are commonly used to produce large amounts of recombinant proteins (such as antibodies, enzymes or hormones) for industrial or medicinal use. The lifespan of some of these cell lines is limited due to growth conditions, the nature of the recombinant molecule being expressed (some are toxic) and other unknown factors. The lifespans of industrial cell lines can be extended by including these cell death inhibitors in the growth medium in a concentration range of 1-100 xcexcM.
The factors governing hair growth and loss are largely unknown. There is some evidence, however, that hair follicle regression (referred to as catagen) may be due at least partially to apoptosis. Therefore, it is contemplated that the cell death inhibitors of the present invention can be used to treat hair loss that occurs due to various conditions, including but not limited to male-pattern baldness, radiation-induced or chemotherapy-induced hair loss, and hair loss due to emotional stress, by administering the inhibitors to the hair or hair follicles of an animal. There is also evidence that apoptosis may play a role in the loss of hair color. Therefore, it is contemplated that the cell death inhibitors of the present invention can also be used in treating or preventing cases of premature graying of the hair.
The death of skin epithelial cells can occur after exposure to high levels of radiation, heat or chemicals. It is contemplated that the cell death inhibitors of the present invention can be used to treat, reduce or prevent this type of skin damage. In one particular application, the cell death inhibitors can be applied as part of a topical formulation, e.g. an ointment, to the skin of an animal to treat acute over-exposure to the sun and to prevent blistering and peeling of the skin.
Goldberg et al. (Nature Genetics 13:442-449 (1996)) reported recently that huntingtin, a protein product of Huntington""s disease (HD) gene, can be cleaved by CPP32 but not ICE. The mutation underlying HD is an expansion of a CAG trinucleotide at the 5xe2x80x2 end of the HD gene. The trinucleotide expansion exceeding 36 repeats is associated with the clinical presentation of HD. The CAG expansion promotes cleavage of huntingtin by CPP32, thus links the role of CPP32 in the apoptotic cell death in HD. Compounds of the present invention with CPP32 inhibiting activity are useful in blocking CPP32 induced apoptotic cell death, thus in preventing and treating HD and other disorders characterized by expansion of trinucleotide repeats such as myotonic dystrophy, fragile X mental retardation, spinobulbar muscular atrophy, spinocerebellar atoxia type I and Dentato-Rubro pallidoluysian atrophy.
The cell death inhibitors can also be used to treat or ameliorate small bowel tissue injury after intestinal ischemia-reperfusion, by administering to an animal in need thereof. See Farber, A. et al., J. Vascular Surg. 30:752-760 (1999).
The invention relates to a method of treating, ameliorating or preventing oral mucositis, gastrointestinal mucositis, bladder mucositis, proctitis, bone marrow cell death, skin cell death and hair loss resulting from chemotherapy or radiation therapy of cancer in an animal, comprising administering to the animal in need thereof an effective amount of a caspase inhibitor.
When animals are treated with chemotherapeutic agents and/or radiation to kill cancer cells, an unwanted side effect is the apoptotic death of rapidly dividing non-cancer cells. Such non-cancer cells include cells of the gastrointestinal tract, skin, hair, and bone marrow cells. According to the present invention, caspase inhibitors are administered to such non-cancer cells to prevent apoptosis of such cells. In a preferred embodiment, the caspase inhibitors are administered locally, e.g. to the gastrointestinal tract, mouth, skin or scalp to prevent apoptosis of the gastrointestinal, mouth, skin or hair cells but allowing for the death of the cancer cells. Thus, in one example, it is possible to treat brain cancer with chemotherapy or radiation therapy and protect the outer skin, hair cells, gastrointestinal tract and bone marrow by local administration of a caspase inhibitor. In the case of oral mucositis, the caspase inhibitor can be applied, for example, in the form of a mouth wash or mouth rinse, in a gel, or in the form of an oral slow release lozenge to prevent activation of caspases and apoptotic cell death induced by the chemotherapeutic agent or by radiation. In the case of gastrointestinal mucositis, the caspase inhibitor can be applied in a form such that it is not absorbed systemically or in a form that coats the surface of the gastrointestinal tract, or a suppository formulation for the treatment of gastrointestinal mucositis. In the case of proctitis, the capsase inhibitor may be applied as part of an enema or suppository. In the case of bladder mucositis, the caspase inhibitor may be applied though a bladder catheter. For prevention of radiation or chemotherapy-induced hair loss, the caspase inhibitor can be applied, for example, to the scalp in the form of a hair rinse, hair gel, shampoo or hair conditioner. Importantly, the caspase inhibitor can be applied prior to the administration of the chemotherapeutic agent or radiation, thus preventing or reducing the onset of the damaging effects of the chemotherapeutic agent or radiation to the normal cells.
Compositions within the scope of this invention include all compositions wherein the compounds of the present invention are contained in an amount which is effective to achieve its intended purpose. While individual needs vary, determination of optimal ranges of effective amounts of each component is within the skill of the art. Typically, the compounds may be administered to mammals, e.g. humans, orally at a dose of 0.0025 to 50 mg/kg, or an equivalent amount of the pharmaceutically acceptable salt thereof, per day of the body weight of the mammal being treated for apoptosis-mediated disorders. e.g., neuronal cell death, heart disease, retinal disorders, polycystic kidney disease, immune system disorders and sepsis. Preferably, about 0.01 to about 10 mg/kg is orally administered to treat or prevent such disorders. For intramuscular injection, the dose is generally about one-half of the oral dose. For example, for treatment or prevention of neuronal cell death, a suitable intramuscular dose would be about 0.0025 to about 25 mg/kg, and most preferably, from about 0.01 to about 5 mg/kg.
The unit oral dose may comprise from about 0.01 to about 50 mg, preferably about 0.1 to about 10 mg of the compound. The unit dose may be administered one or more times daily as one or more tablets each containing from about 0.1 to about 10, conveniently about 0.25 to 50 mg of the compound or its solvates.
In a topical formulation, the compound may be present at a concentration of about 0.01 to 100 mg per gram of carrier.
In addition to administering the compound as a raw chemical, the compounds of the invention may be administered as part of a pharmaceutical preparation containing suitable pharmaceutically acceptable carriers comprising excipients and auxiliaries which facilitate processing of the compounds into preparations which can be used pharmaceutically. Preferably, the preparations, particularly those preparations which can be administered orally or topically and which can be used for the preferred type of administration, such as tablets, dragees, slow release lozenges and capsules, mouth rinses and mouth washes, gels, liquid suspensions, hair rinses, hair gels, shampoos and also preparations which can be administered rectally, such as suppositories, as well as suitable solutions for administration by injection, topically or orally, contain from about 0.01 to 99 percent, preferably from about 0.25 to 75 percent of active compound(s), together with the excipient.
Also included within the scope of the present invention are the non-toxic pharmaceutically acceptable salts of the compounds of the present invention. Acid addition salts are formed by mixing a solution of the particular cell death inhibitors of the present invention with a solution of a pharmaceutically acceptable non-toxic acid such as hydrochloric acid, fumaric acid, maleic acid, succinic acid, acetic acid, citric acid, tartaric acid, carbonic acid, phosphoric acid, oxalic acid, and the like. Basic salts are formed by mixing a solution of the particular cell death inhibitors of the present invention with a solution of a pharmaceutically acceptable non-toxic base such as sodium hydroxide, potassium hydroxide, choline hydroxide, sodium carbonate Tris and the like.
The pharmaceutical compositions of the invention may be administered to any animal which may experience the beneficial effects of the compounds of the invention. Foremost among such animals are mammals, e.g., humans, although the invention is not intended to be so limited.
The caspase inhibitors and pharmaceutical compositions thereof may be administered by any means that achieve their intended purpose. For example, administration may be by parenteral, subcutaneous, intravenous, intramuscular, intraperitoneal, transdermal, buccal, intrathecal, intracranial, intranasal or topical routes. Alternatively, or concurrently, administration may be by the oral route. The dosage administered will be dependent upon the age, health, and weight of the recipient, kind of concurrent treatment, if any, frequency of treatment, and the nature of the effect desired. In general, the caspase inhibitors are administered locally to the tissues that are to be protected from apoptosis and separately from the chemotherapeutic agent. For example, cisplatin may be administered by i.v. injection to treat a cancer such as brain, lung, breast, liver, kidney, pancreatic, ovarian, prostatic cancer, and the caspase inhibitor administered locally to treat, ameliorate, or prevent apototic cell death in the mouth or gastrointestinal tract, such as a mouth wash for the treatment of oral mucositis; and IV injectable aqueous solution for the treatment of bone marrow cell death; and an oral formulation suitable for coating the gastrointestinal surfaces or an emema or suppository formulation for the treatment of gastrointestinal mucositis including proctitis. The caspase inhibitors may also be applied through a bladder catheter for the treatment, amelioration or prevention of bladder mucositis. Alternatively or concurrently, the caspase inhibitors may be applied topically to the skin and/or scalp to treat, ameliorate or prevent apoptotic cell death of hair and skin cells. In a further embodiment, the chemotherapeutic agent or radiation may be applied locally to treat a localized cancer such as brain, lung, breast, liver, kidney, pancreatic, ovarian, prostatic cancer, and the caspase inhibitor administered systemically, e.g. by i.v. injection, to treat, ameliorate or prevent apoptotic cell death of the gastrointestinal tract cells, mouth epithelial cells, bone marrow cells, skin cells and hair cells. In the case of oral mucositis in brain cancer treatment, for example, a caspase inhibitor that does not penetrate the blood-brain barrier can be applied, for example, systemically by i.v. injection followed by irradiation of the brain tumor. This would protect the oral mucosa from the harmful effects of radiation but the caspase inhibitor would not protect the brain tumor from the therapeutic effects of radiation. Importantly, the caspase inhibitor can be applied prior to administration of the radiation, thus preventing the onset of the damaging effects of the radiation to the normal mucosa cells.
The pharmaceutical preparations of the present invention are manufactured in a manner which is itself known, for example, by means of conventional mixing, granulating, dragee-making, dissolving, or lyophilizing processes. Thus, pharmaceutical preparations for oral use can be obtained by combining the active compounds with solid excipients, optionally grinding the resulting mixture and processing the mixture of granules, after adding suitable auxiliaries, if desired or necessary, to obtain tablets or dragee cores.
Suitable excipients are, in particular, fillers such as saccharides, for example lactose or sucrose, mannitol or sorbitol, cellulose preparations and/or calcium phosphates, for example tricalcium phosphate or calcium hydrogen phosphate, as well as binders such as starch paste, using, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, tragacanth, methyl cellulose, hydroxypropylmethylcellulose, sodium carboxymethylcellulose, and/or polyvinyl pyrrolidone. If desired, disintegrating agents may be added such as the above-mentioned starches and also carboxymethyl-starch, cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt thereof, such as sodium alginate. Auxiliaries are, above all, flow-regulating agents and lubricants, for example, silica, talc, stearic acid or salts thereof, such as magnesium stearate or calcium stearate, and/or polyethylene glycol. Dragee cores are provided with suitable coatings which, if desired, are resistant to gastric juices. For this purpose, concentrated saccharide solutions may be used, which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, polyethylene glycol and/or titanium dioxide, lacquer solutions and suitable organic solvents or solvent mixtures. In order to produce coatings resistant to gastric juices, solutions of suitable cellulose preparations such as acetylcellulose phthalate or hydroxypropymethyl-cellulose phthalate, are used. Dye stuffs or pigments may be added to the tablets or dragee coatings, for example, for identification or in order to characterize combinations of active compound doses.
Other pharmaceutical preparations which can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer such as glycerol or sorbitol. The push-fit capsules can contain the active compounds in the form of granules which may be mixed with fillers such as lactose, binders such as starches, and/or lubricants such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds are preferably dissolved or suspended in suitable liquids, such as fatty oils, or liquid paraffin. In addition, stabilizers may be added.
Possible pharmaceutical preparations which can be used rectally include, for example, suppositories, which consist of a combination of one or more of the active compounds with a suppository base. Suitable suppository bases are, for example, natural or synthetic triglycerides, or paraffin hydrocarbons. In addition, it is also possible to use gelatin rectal capsules which consist of a combination of the active compounds with a base. Possible base materials include, for example, liquid triglycerides, polyethylene glycols, or paraffin hydrocarbons.
Suitable formulations for parenteral administration include aqueous solutions of the active compounds in water-soluble form, for example, water-soluble salts and alkaline solutions. In addition, suspensions of the active compounds as appropriate oily injection suspensions may be administered. Suitable lipophilic solvents or vehicles include fatty oils, for example, sesame oil, or synthetic fatty acid esters, for example, ethyl oleate or triglycerides or polyethylene glycol-400 (the compounds are soluble in PEG-400). Aqueous injection suspensions may contain substances which increase the viscosity of the suspension include, for example, sodium carboxymethyl cellulose, sorbitol, and/or dextran. Optionally, the suspension may also contain stabilizers.
In accordance with one aspect of the present invention, compounds of the invention are employed in topical and parenteral formulations and are used for the treatment of skin damage, such as that caused by exposure to high levels of radiation, including ultraviolet radiation, heat or chemicals.
One or more additional substances which have therapeutic effects on the skin may also be incorporated in the compositions. Thus, the composition may also contain one or more compounds capable of increasing cyclic-AMP levels in the skin. Suitable compounds include adenosine or a nucleic acid hydrolysate in an amount of about 0.1-1% and papaverine, in an amount of about 0.5-5%, both by weight based on the weight of the composition. Also suitable are xcex2-adrenergic agonists such as isoproterenol, in an amount of about 0.1-2% or cyclic-AMP, in an amount of about 0.1-1%, again both by weight based on the weight of the composition. Other suitable types of additional active ingredients which may be incorporated in the compositions of this invention include any compounds known to have a beneficial effect on skin. Such compounds include retinoids such as Vitamin A, in an amount of about 0.003-0.3% by weight and chromanols such as Vitamin E or a derivative thereof in an amount of about 0.1-10% by weight, both based on the weight of the composition. Additionally, anti-inflammatory agents and keratoplastic agents may be incorporated in the cosmetic composition. A typical anti-inflammatory agent is a corticosteroid such as hydrocortisone or its acetate in an amount of about 0.25-5% by weight, or a corticosteroid such as dexamethasone in an amount of about 0.025-0.5% by weight, both based on the weight of the composition. A typical keratoplastic agent is coal tar in an amount of about 0.1-20% or anthralin in an amount of about 0.05-2% by weight, both based on the weight of the composition.
The topical compositions of this invention are formulated preferably as oils, creams, lotions, ointments and the like by choice of appropriate carriers. Suitable carriers include vegetable or mineral oils, white petrolatum (white soft paraffin), branched chain fats or oils, animal fats and high molecular weight alcohol (greater than C12). The preferred carriers are those in which the active ingredient is soluble. Emulsifiers, stabilizers, humectants and antioxidants may also be included as well as agents imparting color or fragrance, if desired. Additionally, transdermal penetration enhancers can be employed in these topical formulations. Examples of such enhancers can be found in U.S. Pat. Nos. 3,989,816 and 4,444,762.
Creams are preferably formulated from a mixture of mineral oil, self-emulsifying beeswax and water in which mixture the active ingredient, dissolved in a small amount of an oil such as almond oil, is admixed. A typical example of such a cream is one which includes about 40 parts water, about 20 parts beeswax, about 40 parts mineral oil and about 1 part almond oil.
Ointments may be formulated by mixing a solution of the active ingredient in a vegetable oil such as almond oil with warm soft paraffin and allowing the mixture to cool. A typical example of such an ointment is one which includes about 30% almond oil and about 70% white soft paraffin by weight.
Lotions may be conveniently prepared by dissolving the active ingredient, in a suitable high molecular weight alcohol such as propylene glycol or polyethylene glycol.
In addition, these compositions may include other medicinal agents, growth factors, wound sealants, carriers, etc., that are known or apparent to those skilled in the art. The compositions of the invention are administered to a warm-blooded animal, such as human, already suffering from a skin damage, such as a burn, in an amount sufficient to allow the healing process to proceed more quickly than if the host were not treated. Amounts effective for this use will depend on the severity of the skin damage and the general state of health of the patient being treated. Maintenance dosages over a prolonged period of time may be adjusted as necessary. For veterinary uses, higher levels may be administered as necessary.
In the case of an animal suffering from decreased hair growth, the compositions of the invention are administered in an amount sufficient to increase the rate of hair growth. Amounts effective for this use will depend on the extent of decreased hair growth, and the general state of health of the patient being treated. Maintenance dosages over a prolonged period of time may be adjusted as necessary. For veterinary uses, higher levels may be administered as necessary.
When the compounds are to be administered to plants, they may be applied to the leaves and/or stems and/or flowers of the plant, e.g. by spraying. The compounds may be spayed in particulate form or dissolved or suspended in an appropriate carrier, e.g. in water or an oil-water emulsion. The compounds may also be combined with the soil of the plant. In this embodiment, the compounds are taken up by the roots of the plant.
In a preferred embodiment, the caspase inhibitor is formulated as part of a mouthwash for the treatment, amelioration or prevention of oral mucositis. Such mouthwashes are aqueous solutions of the caspase inhibitor which may also contain alcohol, glycerin, synthetic sweeteners and surface-active, flavoring and coloring agents. They may also contain anti-infective agents such as hexetidine and cetylpyridinium chloride. The mouthwashes may also contain topical anesthetics (e.g. benzocaine, cocaine, dyclonine hydrochloride, lidocaine, proparacaine hydrochloride or teracaine hydrochloride), for example, for relieving pain of radiation or chemotherapy-induced sores. The mouth washes may have either acidic or basic pH. See Remington""s Pharmaceutical Sciences, A. R. Gennaro, ed., Mack Publishing Company (1990), pp. 1045, 1046, 1526 and 1965.
In another preferred embodiment, the caspase inhibitor is formulated as an oral formulation which is capable of coating the gastrointestinal surfaces for the treatment, amelioration or prevention of gastrointestinal mucositis. Examples of gastrointestinal mucositis include esophageal mucositis, gastric mucositis, and intestinal mucositis. Such formulations may comprise gastric antacids such as aluminum carbonate, aluminum hydroxide gel, bismuth subnitrate, bismuth subsalicylate, calcium carbonate, dihydroxyaluminum sodium carbonate, magaldrate, magnesium carbonate, magnesium hydroxide, magnesium oxide, sodium bicarbonate, milk of bismuth, dihydroxyaluminum aminoacetate, magnesium phosphate, magnesium trisilicate and mixtures thereof. Other additives include without limitation H2-receptor antagonists, digestants, anti-emetics, adsorbants, and miscellaneous agents. See Remington""s Pharmaceutical Sciences, A. R. Gennaro, ed., Mack Publishing Company (1990), pp. 774-778.
Chemotherapy agents such as cisplatin and radiation therapy often induce early and late onset emesis in the patient. Thus, in one embodiment an antiemetic is coadminstered together with the caspase inhibitor to avoid emesis and retain contact of the caspase inhibitor with the gastrointestinal tract. Examples of such antiemetics include without limitation compounds that block the dopaminergic emetic receptors such as metoclopramide and trimethobenzamide, and cannabinoids. Metoclopramide may be administered orally prior to and/or during chemotherapy/radiation therapy/caspase inhibitor therapy to prevent the early emesis response and then later by intranasal administration according to U.S. Pat. Nos. 5,760,086 and 4,536,386 to prevent delayed onset emesis. During the period after chemotherapy/radiation therapy, both the caspase inhibitor and the antiemetic may be coadministered to treat, ameliorate or prevent gastrointestinal mucositis.
In a further embodiment, the caspase inhibitor may be formulated as an IV injectable solution for the treatment, amelioration or prevention of bone marrow cell death.
The compositions of the compositions may be administered to a warm-blooded animal, such as human, already suffering from chemotherapy or radiation therapy-induced non-cancer cell death, or, more preferably, before or during therapy with chemotherapy or radiation.
The following examples are illustrative, but not limiting, of the method and compositions of the present invention. Other suitable modifications and adaptations of the variety of conditions and parameters normally encountered in clinical therapy and which are obvious to those skilled in the art are within the spirit and scope of the invention.

Substituted alpha-hydroxy acid caspase inhibitors and the use thereof

Abstract: where R1-R5, X and Z are defined herein. The present invention also relates to the discovery that compounds having Formula I are potent inhibitors of caspases and apoptotic cell death. Therefore, the inhibitors of this invention can retard or block cell death in a variety of clinical conditions in which the loss of cells, tissues or entire organs occurs.


The invention is characterized in that it comprises a toolpath generating routine and system for generating a plurality of control points directly from image data representing an image to be engraved. The control points are used to generate a toolpath which, in turn, will be used to energize an engraving head such that a tool or stylus will engrave a pattern of engraved areas in response to the toolpath. An engraving system and method for engraving at least one engraved area is shown having an engraving head tuner for tuning an engraving head such that the frequency characteristic of the engraving head defines a substantially constant gain for frequencies less than a predetermined frequency. The invention is further characterized in that it incudes a system and method for interactively or automatically tuning the engraving head, interactively adjusting the filter characteristics (including the filter coefficients for the filters used on the engraving head) and for being responsive to the type of image data (whether continuous tone data or linework data). The invention is characterized in that it synthesizes the screening function so as to more accurately reproduce the image to be engraved by engraving multiple frequency cells where single cells would be engraved in the past.

1. Field of Invention
This invention relates to gravure engraving and, more particularly, to an engraving system and method for providing an improved engraved image by utilizing digital toolpath planning, digital tuning and closed loop feedback control.
2. Description of the Related Art
The process of traditional electromechanical engraving consists of cutting small areas or cells of copper from a surface of a copper cylinder. In the traditional process, the cells are formed by superimposing a screening signal and an image signal. The screening signal is an AC sinusoidal waveform and the image signal is added to it to cause a cutting tool or stylus to move or oscillate to engrave the cells.
In the past, most efforts to improve the quality of an engraved image were focused upon modifications to the image signal. Moreover, edge enhancement, selective linearization, speeding up tuning of the engraving head, and pulse modulation were also used to modify the image signal to improve the engraving quality. One or more of these concepts in prior art engraving systems shown in U.S. Pat. Nos. 5,438,422; 5,424,845; 5,621,533; 5,329,215; 5,416,597; 5,424,846; 5,402,246; 5,454,306; 5,475,914; 5,555,473; 5,440,398; 5,493,939; 4,357,633; 4,438,460; 4,450,486; 4,451,856; 4,500,929; 5,492,057; 5,029,011; 5,519,502; 5,583,647; 5,491,559; 5,422,958; 5,293,426; and 5,617,217 disclose apparatus and methods of the general type used in processes in the past.
Thus, it should be apparent that attempts made to improve engraving quality focused upon, for example, modification of the image signal.
Similarly, U.S. Pat. Nos. 4,245,260 and 5,519,502 illustrate techniques for linearizing and shifting of engraved areas to provide a higher quality engraving. For example, U.S. Pat. No. 5,245,260 discloses techniques for modifying a screening signal in order to control the placement of the cell.
What is needed, therefore, is a system and method which synthesizes the image signal and the screening function as a reference wave form which represents the desired stylus toolpath, thereby reducing or eliminating the need to modify the image and screening signals altogether.
Another problem with the approaches of the past is that the screening and layout of the cells were directly dependent upon the AC sinusoidal waveform, thereby eliminating the flexibility of the engraving quality because prior screening waveforms have consisted of constant AC sinusoids which were difficult to modify sensitive to the image to be engraved. What is also needed, therefore, is a simple, yet effective, method and apparatus for transforming data associated with an image to be engraved into a signal which can be synthesized as an arbitrary toolpath derived directly from the image data.
Moreover, in the past, the mechanical structure of an engraving head exhibited resonance characteristics such that at approximately 2 KHz and 5.5 KHz, the engraving head produced increased output. In order to eliminate these undesired resonances, notch filters were added so that the frequency response of the engraving head was more predictable. Due to the nature of the filter algorithms for the notch filters, a generally smooth, but decreasing, response was achieved. The aforementioned U.S. Pat. Nos. 4,357,633; 4,438,460; 4,450,486; 4,500,929 disclose engraving apparatus and methods of the general type which utilize filtering processes of the past.
Unfortunately, the traditional filtering techniques generally produced an engraving head frequency response which did not carry enough amplitude at higher frequencies, such as frequencies in excess of 5.5 KHz. In addition, the techniques of the past did not permit a user to interactively and easily change the characteristics, such as filter coefficients, of the filters in order to manipulate or tune the engraving head as desired. In the past, the filter characteristics were subject to electronic component errors and could not be moved from one circuit board to another with the required precision.
What is needed, therefore, is a system and method which characterizes the engraving head digitally such that the tuning filter characteristics may be stored separate from the tuning circuitry. The digital filter characteristics may then be archived and in the event of circuit failures loaded into the memory of a replacement circuit with sufficient precision to yield the desired engraving head response characteristic.
In the past, correcting errors or calibrating the engraving head was performed in various manners using various techniques, such as the techniques shown in U.S. Pat. Nos. 5,029,011; 5,293,426; 5,416,597; 5,422,958; 5,438,422; 5,440,398. For example, in some calibrating processes of the past, various characteristics of an individual cell in a test cut were measured and compared to a desired characteristic. If the difference between the desired characteristic and actual characteristic were greater than a predetermined tolerance, then the engraving head was adjusted to account therefor. Typically, the prior art processes utilized optics, strobing, and focusing equipment to achieve such measurements and correction. What is needed is a tool velocity and position sensing system and feedback system and method which is simple in design, relatively inexpensive and easy to implement.
What is needed, therefore, is a method and system for affectively manipulating the placement of an engraved area directly from the image data without either using or manipulating the screening signal.
In the past, the resultant head response characteristic after the lengthy tuning process was subject to the tuning operator's subjective judgement as to tune quality. This led to variations from head to head and difficulty in matching engraving image quality between different engravers and also between heads on multiple headed publications engravers.
What is needed, therefore, is a method and system for automating the tuning process thus removing the variations in engraving head response characteristics. Such a system will improve tuning repeatability in addition to shortening the time required to tune an engraving head.

Engraving system and method with arbitrary toolpath control


A soft demodulation method and apparatus including calculating partial sums for a unit of each predetermined number of bits of a codeword received from a channel; calculating a value of each entry of the decoding table by referring to the partial sums; and detecting a maximum among values of all entries of the decoding table and calculating a log-likelihood ratio (LLR) using the detected maximum. Accordingly, it is possible to reduce the amount of computation required to perform a soft demodulation process using run-length limited (RLL) codes and to simplify the soft demodulation process.

1. Field of the Invention
The present invention relates to data decoding, and more particularly, to a soft demodulation method and apparatus.
2. Description of the Related Art
In an environment where inter symbol interference (ISI) exists, such as a high-density optical recording medium, data is modulated by using run-length limited (RLL) codes.
When conventional RLL codes are decoded, a channel demodulator, such as a Viterbi decoder, detects codewords from a signal input via a channel, and an RLL decoder decodes the codewords into datawords by referring to a decoding table.
Recently, soft demodulators and soft decoders have been increasingly used for a variety of purposes. The Viterbi decoder directly outputs a codeword, which contains an error and simply has a value of "1" or "−1". This type of modulation is called hard demodulation. In soft demodulation, however, a soft demodulator receives a channel signal and outputs a probability value of a codeword. In other words, the output of the soft demodulator has an analog value, such as "0.8" or "−0.8", containing the probability of a codeword having a value of 1 or −1. The soft demodulator receives data indicating the probability value of the codeword and outputs a probability value of a dataword. Then, a soft encoder, such as a turbo encoder, receives the probability of the dataword from the soft demodulator and encodes the codeword into the dataword.
A turbo decoding process that requires soft demodulation is taught by Laura L. McPheters and Steven W. McLaughlin in "Turbo-Coded Optical Recording Channels with DVD Minimum Mark Size," IEEE Transactions on Magnetics, Vol. 38, No. 1, January 2002, pp. 298˜302.
FIG. 1 is a block diagram of a conventional encoding/decoding apparatus. Referring to FIG. 1, an encoding/decoding apparatus 100 includes a turbo/low density parity check code (LDPC) encoder 110, a modulator 120, a reader/writer 130, a soft demodulator 150, and a turbo/LDPC decoder 160.
Data is input to the turbo/LDPC encoder 110, which encodes the data by using a soft encoding method, such as an LDPC encoding method or a turbo encoding method. The modulator 120 modulates data output from the turbo/LDPC encoder 110 in a predetermined demodulation manner that uses, for example, an RLL code. The reader/writer 130 records the modulated data on a recording medium 140 or reads data from the recording medium 140. The soft demodulator 150 receives data indicating a probability value of a codeword from the reader/writer 130 and then outputs a log likelihood ratio (LLR), which corresponds to a probability value of each bit of a dataword. The turbo/LDPC decoder 160 carries out a soft decoding on data output from the soft demodulator 150 taking into consideration how the corresponding data has been encoded. Thereafter, the turbo/LDPC decoder 160 outputs the soft-decoded data.
The soft demodulator 150 obtains the LLR by calculating a posteriori probability (APP) (dk=1) and APP(dk=0). APP(dk=1) represents the probability of demodulated data having a value of "1", and APP(dk=0) represents the probability of demodulated data having a value of "0". APP(dk=1) and APP(dk=0) are obtained in the following manner. If a codeword, which is used for determining a dataword, is comprised of N bits, values of (rm−2*cm−1))2 (where m=1, . . . , N) for bits of each codeword that sets a bit of the dataword to 1 are summed up. In short, APP(dk=1) can be obtained by summing up an exponential value of (rm−2*cm−1))2 for each codeword that sets a bit of the dataword to 1, which is shown in Equation (1) below.
                              APP                                (                                          d                k                            =              1                        )                          =                              ∑                          j              ∈                                                S                  1                                                                  (                  k                  )                                                                                exp                                      [                                                r                  m                  j                                -                                                      (                                                                  2                        *                                                  c                          m                          j                                                                    -                      1                                        )                                    2                                            ]                                                          (        1        )
In Equation (1), j indicates that a j-th dataword has a value of 1.
Likewise, APP(dk=0) is obtained using Equation (2) below.
                              APP                                (                                          d                k                            =              0                        )                          =                              ∑                          j              ∈                                                S                  0                                                                  (                  k                  )                                                                                exp                                      [                                                r                  m                  j                                -                                                      (                                                                  2                        *                                                  c                          m                          j                                                                    -                      1                                        )                                    2                                            ]                                                          (        2        )
LLR(dk) is obtained by exponentiating a ratio between the probability APP(dk=0) of the j-th bit of the dataword dk having a value of 0 and the probability APP(dk=1) of the j-th bit of the dataword dk having a value of 1, a process which is shown in Equation (3) below. LLR(dk) is an output of the soft demodulator 150.
                              LLR                                (                          d              k                        )                          =                  Log                                              (                                                APP                                                        (                                          d                      k                                        )                                                  =                1                            )                                      (                                                APP                                                        (                                          d                      k                                        )                                                  =                0                            )                                                          (        3        )
If it is too complicated to exponentiate the ratio between APP(dk=1) and APP(dk=0), LLR(dk) can be obtained by subtracting APP(dk=0) from APP(dk=1). The structure of the soft demodulator 150, which calculates LLR(dk) in this manner, is illustrated in FIG. 2.
Referring to FIG. 2, the soft demodulator 150 includes a decoding table 151, an entry calculator 152, a maximum detector 153, and an LLR calculator 154. The decoding table 151 is illustrated in FIG. 3.
The entry calculator 152 performs a predetermined calculation on a read code signal using each entry of the decoding table 151. Hereinafter, the predetermined calculation will be described more fully with reference to FIG. 4. More specifically, the entry calculator 152 associates each bit of an input code signal 410 with each bit of the entry 420. If a bit of the entry 420, corresponding to a given bit of the input code signal 410, has a value of 0, the given bit of the input code signal 410 is multiplied by −1. On the other hand, if a bit of the entry 420, corresponding to the given bit of the input code signal 410, has a value of 1, the given bit of the input code signal 410 is multiplied by +1. The entry calculator 152 performs this type of multiplication on each bit of the input code signal 410 and then sums up all multiplication results, thus obtaining a result 430 of the predetermined calculation.
For example, assume that the input code signal 410 is "r0r1 . . . r17" and the entry is "000101 . . . 100", as shown in FIG. 4. Because the fourth, sixth, ninth, eleventh, fourteenth, and sixteenth bits of the entry 420 have a value of 1 and the other bits of the entry 420 have a value of 0, r3, r5, r8, r10, r13, and r15 are multiplied by +1, and the other bits of the are multiplied by −1. Thereafter, the multiplication results are summed up. The entry calculator 152 carries out the predetermined calculation on the input code signal 410 as many times as the number of entries of the decoding table 151.
The maximum detector 153 receives as many results of the predetermined calculation from the entry calculator 152 as the number of entries of the decoding table 151 and detects a maximum among the predetermined calculation results.
The LLR calculator 154 calculates LLR(dk) by subtracting a maximum regarding "0" from a maximum regarding "1", by a process as shown in Equation (4) below. Thereafter, the LLR calculator 154 outputs LLR(dk).
                                                                        LLR                                                  (                                      d                    k                                    )                                            =                                                                                max                                          j                      ∈                                                                        S                          1                                                                                (                          k                          )                                                                                [                                                                  ∑                                                  m                          =                          0                                                                          t                          -                          1                                                                                r                          m                          j                                                *                        2                                                                          (                                                                                c                              m                              j                                                        -                            1                                                    )                                                                                ]                                                  -                                                                                max                                      j                    ∈                                                                  S                        0                                                                                (                        k                        )                                                                                [                                                            ∑                                              m                        =                        0                                                                    t                        -                        1                                                                                r                        m                        j                                            *                      2                                                                    (                                                                              c                            m                            j                                                    -                          1                                                )                                                                              ]                                                                                (        4        )
LLR(dk+1) can be obtained by simply substituting k+1 into Equation (4), as shown in Equation (5) below.
                                                                        LLR                                                  (                                      d                                          k                      +                      1                                                        )                                            =                                                                                max                                          j                      ∈                                                                        S                          1                                                                                (                                                      k                            +                            1                                                    )                                                                                [                                                                  ∑                                                  m                          =                          0                                                                          t                          -                          1                                                                                r                          m                          j                                                *                        2                                                                          (                                                                                c                              m                              j                                                        -                            1                                                    )                                                                                ]                                                  -                                                                                max                                      j                    ∈                                                                  S                        0                                                                                (                                                  k                          +                          1                                                )                                                                                [                                                            ∑                                              m                        =                        0                                                                    t                        -                        1                                                                                r                        m                        j                                            *                      2                                                                    (                                                                              c                            m                            j                                                    -                          1                                                )                                                                              ]                                                                                (        5        )
In Equation (5), S0(k+1) indicates a set of entries of the decoding table 151 of FIG. 3, and S1(k+1) indicates a set of entries of a decoding table, which is very similar to the decoding table 151.
If soft modulation is carried out using the decoding table 151, as many as 85,000 calculations are required. Here, 85,000 is obtained by multiplying a total number of additions and subtractions using bits of each entry of the decoding table 151, i.e., 17, by the number of entries of the decoding table 151, i.e., 5,000.
As described above, in the related art, as the size of an APP decoding table used for soft demodulation increases, the time taken to calculate an LLR increases, and the APP decoding table becomes remarkably complicated.


A liquid crystal display method to display an image according to an image signal, comprises changing a ratio of a display period and a non-display period of the image according to the image signal.

1. Field of the Invention
The present invention relates to a display method of a liquid crystal display device.
2. Description of the Related Art
In recent years, a performance of a liquid crystal display (hereinafter, called as an "LCD") has been improved, and the LCD begins to spread to the conventional television field where a cathode ray tube (hereinafter, called as a "CRT") is chiefly used.
The LCD uses transistors as a select switch for each pixel, and adopts a display method (hereinafter, called as a "hold-type display"), in which a displayed image is held for 1 frame period. In contrast, in CRT, a display method (hereinafter, called as an "impulse-type display"), in which a selected pixel is darkened immediately after the selection period of the pixel, is adopted. Thus, the LCD is different from CRT in time axis characteristic in an image display. Therefore, when the motion image is displayed, image deterioration such as blurring the image etc. is caused. This reason will be easily explained.
When an observer follows and observes the moving object of the motion image (when the eyeball movement of the observer is a following motion), even if the image is rewritten, for example, in 60 Hz, the eyeball has a characteristic to smoothly follow the moving object.
The black is displayed between each frame of the motion image rewritten in 60 Hz in case of the impulse-type display like the CRT. That is, the black is displayed excluding a period when the image is displayed, and 1 frame of the motion image is presented respectively to the observer as an independent image. Therefore, the image is observed as a clear motion image in the impulse-type display.
However, in the hold-type display, the displayed image of 1 frame of the motion image is held for 1 frame period, and is presented to the observer during the corresponding period as a still image. Therefore, even though the eyeball of the observer smoothly follows the moving object, the displayed image stands still for 1 frame period as shown in FIG. 1A. Therefore, the shifted image is presented according to the speed of the moving object on the retina of the observer as shown in FIG. 1B. Accordingly, since the observer perceives the image with which the shifted images are overlapped, an impression that the motion image is obscure is given to the observer. In a word, a sharpness of the motion image is lost. In addition, since the deviation between the images presented on the retina of the observer becomes large when the velocity of the motion image becomes large, the impression that the image is more obscure is given.
On the other hand, there is a white brightness as a factor to decide the picture quality of the motion image besides the factors as mentioned above.
In the CRT, the amount of the current flowing to the electron gun is controlled according to the average brightness level of the image signal of 1 frame (hereinafter, called as an "APL"). This reason is as follows. A disadvantage such that a load of a high-voltage circuit becomes too large occurs when a high-voltage current is flown to the electron gun according to the image signal in case of a high APL image (i.e., bright image on the entire screen). Therefore, the CRT comprises a circuit (hereinafter, called as an "ABL circuit"), which automatically controls brightness corresponding to the APL and a circuit (hereinafter, called as an "ACL circuit"), which automatically controls the contrast ratio.
For example, when the image signal with the high APL is displayed on the CRT, the amount of the current flowing to the electron gun is limited by an operation of the ABL circuit. Thereby, the brightness of the entire screen lowers. However, the ACL circuit operates at this time, the contrast of the image signal is increased, and a dark part is displayed more darkly. Since a relative contrast becomes high in spite of lowering the brightness of the entire screen, a high dynamic range image can be obtained with such a processing. In contrast, when the image signal with the low APL is displayed, the punched-up image with high contrast can be similarly obtained since the brightness of a bright image area becomes large.
On the other hand, in the LCD, it is preferable to reduce the impulse rate (ratio of which the image is displayed for 1 frame period), when only a priority is given to a sharpness of the motion image. However, when the impulse rate is reduced, the white brightness is insufficient. Therefore, the contrast ratio lowers due to insufficiency of the white brightness and the reality of the motion image lowers when the image with the high APL is displayed. For example, if the brightness of the backlight is raised to supplement insufficiency of the white brightness, oppositely, the entire screen becomes whitish when APL is low and the image is dark.
As described above, the picture quality of the motion image is decided by a sharpness of the displayed motion image and white brightness. However, there is a disadvantage that the image becomes obscure when the motion image is displayed, and the sharpness is lost in the conventional liquid crystal display device. To solve such a disadvantage, when reducing the ratio of the display period of the image, that is, the ratio of the black display period is enlarged, there is a disadvantage that the power of the motion image lowers because of the decrease in dynamic range due to the white brightness insufficiency.
To cancel the blurring phenomenon, the field inversion method is proposed (see Japanese Patent Application KOKAI Publication No. 2000-10076). This is a method of controlling the transmitting of the light in an analog fashion in one polarity, using the operation characteristic of the monostable liquid crystal material which does not transmit the light in the other polarity, dividing 1 frame into two fields, that is, first and second fields, transmitting the light in the first field, and not transmitting the light in the second field. A display device of the liquid crystal panel using a bent-alignment cell is proposed (see, Japanese Patent Application KOKAI Publication No. 11-109921). A display method in each proposal is close to the impulse display by providing an image display period and the black display period.
However, in the field inversion method, display duty is just only 50%, since the application time of the voltage to two poles is equal so that the DC component should not remain in the liquid crystal material. The display duty is defined by the following equation.display duty=display period/(display period+non-display period)×100  (1)
In addition, a crosstalk is occurred easily in the field inversion method.
In a method of dividing the field, it is necessary to increase the number of screen dividings to change the display duty. Therefore, an irregular display (brightness change like the tie suiting) occurs by the difference of the signal line driving circuit. Since it is necessary to change the scanning line driving frequency in order to change the display duty, it is more difficult to set the display duty in detail. Therefore, the high quality display cannot be obtained according to the display image.
There are many liquid crystal display devices in which the number of gray-scales of each color of RGB (R=red, G=green, B=blue) to express the color. However, a large number of display colors, such as eight bits, ten bits, come to be required in the future. Therefore, the number of colors is increased by using a frame rate control (hereinafter, called as an "FRC") technology, which displays two or more times for 1 frame period. However, in inventors experiment, even if the number of colors is reduced in the motion image from the number of colors in the still image, it is partly confirmed not to be able to recognize the difference so much.
When all pixels in the display area are the same alignment (for example, a first alignment), 1 frame is divided into two fields, writing by +polarity is performed in the field of the first half and erasure by −polarity is performed in the field of the latter half to perform the exchange drive. In this case, one scanning line period is a half of conventional ones by dividing 1 frame into two fields. The writing insufficiency might be occurred, and the contrast might be lowered.

Display method for liquid crystal display device