Method for treating dermal pre-melanoma conditions which include administering an effective amount of a photosensitive agent to a dermal pre-melanoma cell and activating the photosensitive agent, thereby treating a dermal pre-melanoma condition.

The present invention relates to methods for treating pre-melanomas. In particular the present invention relates to methods for treating a pre-melanoma cell or condition using a photosensitive agent.
Photodynamic Therapy
Photodynamic therapy (PDT) is the use of an agent, given orally, intravenously, or topically, that can be activated or energized by light to inactivate or to cause necrosis of a target tissue in which the agent has accumulated. Activation of the agent results in the formation of new molecules and free radicals that form other chemicals that, in turn, can destroy the target tissue to varying extents or otherwise have a deleterious effect on the target tissue. Thus, photodynamic therapy involves the application of a photosensitive (photochemotherapeutic) agent to an affected area of the body, followed by exposure of the photosensitive agent to light of a suitable wavelength to activate the photosensitive agent and convert it into a cytotoxic form, whereby the affected cells are killed or their proliferative potential is diminished.
A photosensitive agent can exert its desired effects by a variety of mechanisms, directly or indirectly. Thus for example, a photosensitizer can become directly toxic when activated by light, whereas other photosensitive agents act to generate toxic species, for example, oxidizing agents such as singlet oxygen or other oxygen-derived free radicals, which are extremely destructive to cellular material and biomolecules such as lipids, proteins and nucleic acids.
PDT is not effective to treat thick lesions such as the skin cancer melanoma. Hence, PDT is not used to treat melanoma. Karrer, S., et al., Role of Lasers and photodynamic therapy in the treatment of cutaneous malignancy, Am J Clin Dermatol 2001;2(4):229-37. See also Brown J. E., et al., Photodynamic therapyxe2x80x94new light on cancer treatment, JSDC 115;249-253:1999.
Photodynamic therapy has been used to treat various superficial (i.e. thin, exterior, surface lesions) abnormalities or disorders of the skin as well as to treat macular degeneration. Thus, PDT has been used to treat various cancerous lesions, such as basal cell carcinoma including certain non-malignant lesions, and superficial skin lesions such as actinic keratoses (xe2x80x9cAKsxe2x80x9d) and psoriasis.
The PDT topical agent 5-aminolevulinic acid (5-ALA) has been used to selectively photosensitize the atypical cells of an AK lesion. Approximately 14 to 18 hours following application of the 5-ALA, the skin is exposed to a light source and the cells of the AK lesion are destroyed. Common side effects of PDT include erythema, stinging/burning, edema, and scaling or crusting of the lesion. The primary disadvantage of PDT to treat AK is the need for treatment over a 2-day period.
Precancerous Skin Lesions
Perhaps the most common precancerous skin lesion is actinic keratose (AK), also known as solar keratoses, which are common, sun-induced precancerous skin lesions that are confined to the epidermis. AK typically appears as circumscribed, rough, scaly patches on sun exposed skin, ranging from flesh-colored to reddish brown. Due to their distinctive roughened quality, AKs are easy to detect by palpation or by visualization. AKs are usually 1 to 3 mm in diameter, but may be larger in size and may appear in clusters. AKs are dynamic in nature. Although most AKs are asymptomatic, some may exhibit signs and symptoms such as thickening, burning, tenderness, or itching. AKs may also progress to squamous cell carcinoma (SCC), a form of skin cancer. AKs are most prevalent in fair-skinned individuals with a history of significant sun exposure. The prevalence of AKs increases with advancing age, and AKs are more common in men than women. AKs are more common in immunosuppressed patients and in patients with some genetic disorders (such as xeroderma pigmentosum). Due to high rates of prevalence and incidence, destruction of AKs is the most commonly performed outpatient dermatologic procedure in the United States.
The current management options for visible or easily perceived and diagnosed precancerous dermatological lesions such as AKs include cryosurgery with liquid nitrogen, topical treatments, and curettage. Other less common treatments include dermabrasion, excision, chemical peels, laser therapy, and photodynamic therapy.
Topical treatments, such as the chemotherapeutic agent 5-fluorouracil (5-FU), are most commonly used for patients with multiple lesions. The 5-FU cream is applied to the entire region that is affected, and the recommended course of treatment involves several applications per day over a 2 to 4 week time span. 5-FU selectively targets the damaged skin, causing an inflammatory response with erythema, necrosis, and erosion. Numerous side effects are associated with 5-FU, including pain or irritation, tenderness, ulceration, burning, and inflammation. As a result, patient compliance is a significant concern with this treatment.
Curettage, which involves the use of a curette to scrape away the lesion, is another common method of treatment for easily perceptible precancerous skin lesions. In some instances, curettage may be used in combination with electrosurgery to stop bleeding or apply more damage to the affected area. The primary advantage of curettage is the ability to submit the specimen for histologic analysis, particularly in cases where invasive squamous cell carcinoma is suspected. Disadvantages of curettage include the need for local anesthesia and the potential for scarring.
Melanoma and Pre-Melanoma
Melanoma is a type of potentially fatal skin cancer. A melanoma tumor develops from abnormal melanocytes in the lower epidermis. A melanocyte is a pigment cell which can become abnormal to varying degrees. The highest degree of abnormality of a melanocyte cell is to become a melanoma cell. A melanoma cell is a malignancy (i.e. a cancer or tumor cell) that invades and destroy surrounding tissues and can metastasize to distant sites in the body via the blood and lymph systems.
Melanomas are graded according to the deepest depth to which they penetrate the skin tissue. The depth may be described in terms of millimeters (Breslow) or by the depth level of various structures in the skin tissue to which the melanoma has penetrated. Melanoma is curable in its earliest phases and can arise on its own or from an atypical or unusual mole. More than 90% of melanomas occur on the visible portions of the body, that is on the skin.
The incidence and mortality rates of malignant melanoma continue to rise dramatically throughout the world. In the United States, it is estimated that nearly one in 90 Americans will develop melanoma. Melanoma is one of the most feared neoplasms because of the high mortality associated with metastasis. Melanomas usually metastasize first via the lymphatic system, with involvement of regional nodes, and then via blood vessels, with dissemination to subcutaneous tissue and to the liver, lungs, and brain. The presence of regional lymph node metastasis is predictive of a poor prognosis.
As set forth, melanomas arise from melanocytes and are typically pigmented (melanotic) due to accumulation of melanin, which imparts a dark color to melanomas. Some melanocytes may be less well differentiated and therefore produce little or no melanin. Melanomas arising from melanocytes can be nonpigmented or amelanotic.
Approximately 70 percent of melanomas are of the superficial spreading type. Generally, this type of melanoma is characterized by a pre-existing mole that slowly changes over a period of one to five years which is then followed by a period of rapid changes close to the time that the melanoma is diagnosed. Typically, this type of melanoma first appears as a very dark area in an existing mole. As the pre-melanoma enlarges, the edges usually appear notched or indented. Superficial spreading melanoma may appear anytime after puberty and is seen more often in women than in men.
Nodular melanoma is the second most common type of melanoma, accounting for approximately 15 to 30 percent of cases. These melanomas usually do not appear in an existing nevi. Instead, they start as melanomas and are often darker in color than the superficial spreading type. Nodular melanomas typically take on a blue-black appearance and look like blood blisters. Some may have shades of purple, gray or red in them, or lack color and have a fleshy appearance. They are usually 1 cm to 2 cm or larger in diameter. Nodular melanomas appear more often in men and are usually seen in middle age, although they may appear at any age.
A small percentage of melanomas, 4 to 10 percent, are lentigo maligna melanomas. They differ greatly from other types in that they usually do not metastasize. They are seen most often on the face and neck, are typically large (greater than 3 cm) and are tan-colored with shades of brown. They appear most often in Caucasian women who are over the age of 50.
Acral lentiginous melanomas generally occur on the palms of the hand or the soles of the feet. They may also be seen under a fingernail or toenail. Their incidence is low in Caucasians (only 2 to 8 percent of those having melanoma), but substantially higher among darker-skinned individuals with melanoma (approximately 35 to 60 percent). They appear on average over a two-and one-half-year period and resemble a flat tan or brown stain. It is common for this type of melanoma to break into a sore. Acral lentiginous melanoma is usually seen in persons who are over the age of 60. Physicians currently use CT scans, radionuclide bone scans, liver and spleen scintigraphy, and magnetic resonance imaging to evaluate the extent of melanoma. Usually these tests are conducted when specific symptoms require investigation. However, a biopsy is currently the only recognized definitive means of identifying the melanoma.
Melanoma usually occurs in adults, but it may occasionally be found in children and adolescents. Men most often get melanoma on the trunk (the area of the body between the shoulders and hips) or on the head or neck, and women most often get melanoma on the arms and legs. In rare cases, it can develop in parts of the body not covered by the skin, such as the eyes, mouth, large intestine, or vagina.
Melanoma can be difficult to cure, and is often lethal. In the U.S. there are about 38,000 new cases of melanoma a year and approximately 7,000 melanoma deaths occur every year in the U.S. Current therapy for melanoma has many deficiencies and drawbacks. The first line therapy of choice is to remove the melanoma tissue as well as a substantial area of tissue surrounding the melanoma so as to also remove precancerous, premelanoma cells which typically exist in proximity to the melanoma. Premelanoma cells are those melanocytes in proximity to a melanoma, such as, for example, a lentigo maligna melanoma, which while not malignant, are irregular and/or atypical melanocytes which if left untreated often become malignant over time. Surgical removal of the melanoma and surrounding tissue results in scaring and the removal of a large areas of tissue can necessitate use of skin grafts. Additionally, where a facial melanoma is removed a highly undesirable cosmetic outcome can result due to the scaring and discoloration of the new skin graft.
Early treatment of melanoma is highly desirable for patient prognosis and there is a need for an effective treatment of melanoma while it is still a pre-melanoma condition. Additionally, there is a need for an effective treatment of pre-melanoma cells in the vicinity of excised melanoma tissue. Thus it is very preferable to treat melanoma in the pre-melanoma stage. Treatment of melanoma at the pre-melanoma stage may greatly increase the prognosis for a patient. Therefore, what is needed are effective methods to treat pre-melanoma. While it is known to treat certain cancerous tissues with PDT and to treat discernable and superficial precancerous tissues (such as AKs) by PDT, there exists no PDT therapy for precancerous pre-melanoma tissues. Note that pre-melanoma cannot be discerned visually or by a tactile examination.
The present invention meets this need and provides for new methods to treat pre-melanoma which involve photodynamic therapy. A pre-melanoma is a precancerous cell or cells that, if left untreated, can develop into a melanoma (cancer) cell. Thus, a pre-melanoma includes pre-superficial spreading melanoma, pre-lentigo melanoma, pre-nodular melanoma and pre-acral lentiginous melanoma. A pre-melanoma cell can be identified, for example, histologically as an atypical or irregular melanocyte.
In accordance with the present invention there are provided methods for treating a pre-melanoma, such as a dermal pre-melanoma, condition and/or for preventing development of a melanoma. By xe2x80x9cdermalxe2x80x9d it is meant the skin which comprises the epidermis, dermis and adjacent subcutaneous tissue. These methods may include administering an effective amount of a photosensitive agent to a pre-melanoma cell and activating the photosensitive agent. In one embodiment, the photosensitive agent is a porphyrin, for example, a porphyrin having formula I:
R22Nxe2x80x94CH2COCH2xe2x80x94CH2COxe2x80x94OR1xe2x80x83xe2x80x83(formula I)
wherein R1 is alkyl or substituted alkyl; and each R2 is independently hydrogen, alkyl or substituted alkyl. An alkyl R1 and/or an alkyl R2 may be substituted with a group selected from the group consisting of hydroxyl, alkoxy, acyloxy, alkoxycarbonyloxy, amino, aryl, oxo and fluoro. In addition, R1 and/or R2 may be interrupted by an atom selected from the group consisting of oxygen, nitrogen, sulfur and phosphorus. Salts of these compositions and mixtures and combinations of the compositions are also contemplated for use in accordance with the present invention.
In accordance with the present invention, the dermal pre-melanoma cell may be, for example, a pre-superficial spreading melanoma cell, a pre-lentigo melanoma cell, a pre-nodular melanoma cell or a pre-acral lentiginous melanoma cell.
In one embodiment of the present invention, the administering includes applying the photosensitive agent to the dermal pre-melanoma cell. The administering may also include waiting for a time period wherein the photosensitive agent reaches an effective concentration in the dermal pre-melanoma cell.
After administration, the photosensitive agent may be activated. The photosensitive agent may be activated by irradiating the dermal pre-melanoma cell with light for an effective length of time and/or an effective wavelength to activate the photosensitive agent.
In one embodiment the dermal pre-melanoma condition is treated by causing necrosis or apoptosis of a dermal pre-melanoma cell and/or by causing a melanoma cell to become a non-melanoma cell. In one embodiment of the present invention a dermal pre-melanoma cell is located at a site near where a melanoma was removed. For example, a dermal pre-melanoma may be within about 0.1 cm of the site from where the melanoma was removed or within about 2 cm of the site from where the melanoma was removed or within about 5 cm of the site from where the melanoma was removed or within about 20 cm or more of the site from where the melanoma was removed.
Any feature or combination of features described herein are included within the scope of the present invention provided that the features included in any such combination are not mutually inconsistent as will be apparent from the context, this specification, and the knowledge of one of ordinary skill in the art.
Additional advantages and aspects of the present invention are apparent in the following detailed description and claims.
The present invention is based upon the discovery that a photosensitive agent can be used to treat a pre-melanoma. A pre-melanoma is a cell or cells that if left untreated can develop into melanoma, for example, superficial spreading melanoma, lentigo melanoma, nodular melanoma and acral lentiginous melanoma. There is no effective current therapy for pre-melanoma except excision. Examples of pre-melanoma are pre-superficial spreading melanoma, pre-lentigo melanoma, pre-nodular melanoma and pre-acral lentiginous melanoma. It is surprising that PDT can be used effectively with regard to a pre-melanoma because the histological nature and biochemical function of a pre-melanoma cell is distinct from that of a cancerous cell and from other precancerous cells such as AK cells. Thus, it was unexpected that a pre-melanoma cell would selectively absorb sufficient photosensitive agent to permit effective treatment by the methods disclosed herein. Additionally, since PDT is ineffective to treat melanoma, it is surprising that PDT can be used to treat pre-melanoma, the precursor of melanoma.
A photosensitizer is a chemical compound which produces a biological effect, for example, a cytotoxic effect, upon photoactivation. A photosensitizer used in accordance with the present invention has a sufficiently low toxicity to permit administration to the patient with a medically acceptable level of safety. In one embodiment, the photosensitizer is essentially nontoxic, except for the desired cytotoxic effect produced locally, upon activation of the photosensitizer.
A single photosensitizer compound can be used alone in the practice of this invention. Alternatively, two or more photosensitizers can be used in a mixture or in a combination or both. The mechanism of the biological effect produced upon photoactivation need not be of a particular type, as long as the desired treatment of pre-melanoma is achieved. The mechanism of the cytotoxic effect may depend upon the particular photosensitizer used. The cytotoxic effect may result from, for example, the generation of a short-lived, highly reactive, diffusible species such as singlet oxygen or free radicals. Singlet oxygen or free radicals may then react with double bonds and initiate free radical chain reactions which may inactivate biologically active molecules such as growth factors or cytokines. Such a reaction process may also degrade or disorganize biological membranes of cells that participate directly or indirectly in forming a pre-melanoma.
The photosensitizer can be chosen, or chemically modified, to optimize its usefulness in specific treatment situations. For example, the photosensitizer may be chemically conjugated to a targeting moiety such as a monoclonal antibody for targeting to a particular tissue. Administration of the photosensitizer may be local or systemic. The administration may be by any suitable route, including topical, intravenous, intraarticular, subcutaneous, intramuscular, intraventricular, intracapsular, intraspinal, intraperitoneal, intranasal, oral, buccal, rectal or vaginal. The preferred route of administration will depend on the size and nature of the pre-melanoma, and on the location of the pre-melanoma.
A photosensitizer agent (or synonymously a photosensitive agent or PDT agent) can be administered to the intended area of target tissue, which target tissue then absorbing and accumulates the agent. In general, healthy tissues eliminate photosensitizer agents used in photodynamic therapy relatively rapidly while the agent is retained in target cell areas for longer periods of time.
Medical practitioners and researchers in the field understand that the optimum time for activation can vary between different photosensitizer compounds, as different compounds can have different bioabsorption rates, stabilities, and elimination rates, and the time can vary as a function of the treatment location in the body, and so forth, as will be appreciated by persons of skill in the field. Predetermined guidelines and protocol for the timing of the irradiation step will often be available in advance for a given photosensitizer agent and specific treatment, or they can be determined empirically for any given set of conditions.
Pre-melanoma is typically found in the skin (i.e. dermal pre-melanoma). However, pre-melanoma may also occur in the eye and is called ocular pre-melanoma or intraocular pre-melanoma. Pre-melanoma may also arise in the meninges, the digestive tract, lymph nodes, or areas where melanocytes are found.
The size, nature, and location of the pre-melanoma being treated may render local administration of the photosensitizer feasible. Local administration may reduce the likelihood of unwanted side effects. In addition, local administration may permit greater control over photosensitizer concentration at the pre-melanoma site.
In the preferred embodiment of the present invention, a photosensitizer is locally administered to a dermal location in close proximity to where a melanoma was removed. For example, after surgically removing a melanoma, a photosensitizer may be applied to an area including and/or surrounding the site of excision. The area of application around the site of excision may be as large or as small as deemed necessary by a treating physician, but is chosen so as to treat pre-melanoma cells which can circumscribe the excised melanoma For example, the area of application may be between about 0.1 cm2 and 1.0 cm2, or between about 0.1 cm2 and about 10 cm2 or between about 0.1 cm2 and about 100 cm2 or between about 0.1 cm2 and about 2000 cm2.
In another embodiment of the present invention, a photosensitizer is locally administered to a site at and/or near a pre-melanoma, that is an atypical or irregular melanocyte. For example, a photosensitizer may be applied to an area including and/or surrounding a pre-melanoma. The area of application may be as large or as small as deemed necessary by a treating physician. For example, the area of application may be between about 0.1 cm2 and 1.0 cm2, or between about 0.1 cm2 and about 10 cm2 or between about 0.1 cm2 and about 100 cm2 or between about 0.1 cm2 and about 2000 cm2.
To facilitate sufficient absorption of the photosensitive agent by pre-melanoma cells in the lower epidermis various chemical transport enhancers (such as the skin lipid fluidizer Azone), and diverse methodologies, such as ionotophoresis, can be used, to thereby enhance percutaneous penetration of the agent to a pre-melanoma cell. For example, decylmethyl sulfoxide (xe2x80x9cDMSxe2x80x9d) is known to increase permeation of the skin. Additionally, ethanol pretreatment of the skin in conjunction with iontophoresis can also be used to facilitate penetration of the selected PDT agent to the lower epidermis. A variety of organic solvents as well as surfactants can also be used for this purpose. Furthermore, use of an adhesive patch for transdermal delivery of a therapeutic drug is known. See e.g. Tonnesen, P. et al., A double blind trial of a 16-hour transdermal nicotine patch in smoking cessation, New Eng J Medicine, 325(5); 311-315: August 1991. The present invention encompasses an adhesive patch (as a PDT agent depot) placed onto the surface of the skin of the patient, where the patch comprises a polymeric carrier which can release a therapeutically effective amount of a PDT agent onto the skin surface of the patient. Application of a PDT agent adhesive, polymeric patch can be preceded by pretreatment of the skin with i.e. ethanol wipes or dermal abrasion, and the patch can be used concurrently or in conjunction with a suitable permeation enhancement methodology such as iontophoresis.
Separately or in conjunction with use of a substance or process to enhance penetration of and accumulation of the PDT agent to pre-melanoma cells, the light source used to activate the PDT agent is selected so as to permit activation of the agent in the lower epidermis. Thus, the light source can comprise a penetrating form of radiation, such as UV radiation or laser light with a focus in the lower epidermis, and/or the irradiation of the target area can be maintained for a time period such that a therapeutically effective amount of the PDT agent accumulated in pre-melanoma cells in the lower epidermis is activated.
Photosensitizers
Various photosensitizers are known and may be used in the practice of this invention. Photosensitizers typically have chemical structures that include multiple conjugated rings that allow for light absorption and photoactivation. They may differ in the properties of light absorption and fluorescence, biodistribution, temporal uptake, and mechanisms of photoactivatable cytotoxicity.
Classes of photosensitizers include hematoporphyrins (Batlle, J. Photochem. Photobiol. B-Biol. 20:5-22 (1993); Kessel, Cancer Let. 39:193-198 (1988)), uroporphyrins, phthalocyanines (Kreimer-Birnbaum, Seminars in Hematology 26:157-173 (1989)), purpurins (Morgan et al., Photochem. Photobiol. 51:589-592 (1990); Kessel, Photochem. Photobiol. 50:169-174 (1989)), acridine dyes, bacteriochlorophylls (Beems et al., Photochem. Photobiol. 46:639-643 (1987); Kessel et al., Photochem. Photobiol. 49:157-160 (1989)), and bacteriochlorins (Gurinovich et al., J. Photochem. Photobiol. B-Biol. 13:51-57 (1992)), porphyrins, bacteriochlorins, naphthalocyanines, texaphyrines, and non-tetrapyrrole photosensitizers.
Some specific examples of suitable photosensitizers which can be used in the practice of the present invention are listed in Table 1.
1. Photofrin(copyright)
2. synthetic diporphyrins and dichlorins
3. hydroporphyrins, e.g., chlorins and bacteriochlorins of the tetra(hydroxyphenyl) porphyrin series
4. O-substituted tetraphenyl porphyrins (picket fence porphyrins)
5. 3,1-meso tetrakis (o-propionamido phenyl) porphyrin
6. verdins
7. purpurins, e.g., tin and zinc derivatives of octaethylpurpurin (NT2), and etiopurpurin (ET2)
8. chlorins, e.g., chlorin e6, and mono-l-aspartyl derivative of chlorin e6
9. benzoporphyrin derivatives (BPD), e.g., benzoporphyrin monoacid derivatives, tetracyanoethylene adducts of benzoporphyrin, dimethyl acetylenedicarboxylate adducts of benzoporphyrin, Diels-Adler adducts, and monoacid ring xe2x80x9caxe2x80x9d derivative of benzoporphyrin
10. low density lipoprotein mediated localization parameters similar to those observed with hematoporphyrin derivative (HPD)
11. sulfonated aluminum phthalocyanine (Pc) sulfonated AIPc disulfonated (AIPcS.sub.2) tetrasulfonated derivative sulfonated aluminum naphthalocyanines chloroaluminum sulfonated phthalocyanine (CASP)
12. zinc naphthalocyanines
13. anthracenediones
14. anthrapyrazoles
15. aminoanthraquinone
16. phenoxazine dyes
17. phenothiazine derivatives
18. chalcogenapyrylium dyes cationic selena and tellurapyrylium derivatives
19. ring-substituted cationic PC
20. pheophorbide(copyright)
21. texaphyrins
22. protoporphyrin
23. tin etiopurpurin
24. methylene blue
25. 5-amino levulinic acid
26. esters of 5-amino levulinic acid
Texaphyrins are aromatic pentadentate macrocyclic xe2x80x9cexpanded porphyrinsxe2x80x9d useful in photodynamic therapy. Texaphyrin is considered as being an aromatic benzannulene containing both 18p- and 22p-electron delocalization pathways. Texaphyrin molecules absorb strongly in the tissue-transparent 700-900 nm range, and they exhibit inherent selective uptake or biolocalization in certain target tissues. Texaphyrins have exhibited significant tumor selectivity as detected by fluorescence and magnetic resonance imaging. Texaphyrins and water-soluble texaphyrins, method of preparation and various uses have been described in U.S. Pat. Nos. 5,798,491, 4,935,498; 5,162,509; 5,252,720; 5,256,399; 5,272,142; 5,292,414; 5,369,101; 5,432,171; 5,439,570; 5,451,576; 5,457,183; 5,475,104 5,504,205; 5,525,325; 5,559,207; 5,565,552; 5,567,687; 5,569,759; 5,580,543; 5,583,220; 5,587,371; 5,587,463; 5,591,422; 5,594,136; 5,595,726; 5,599,923; 5,599,928; 5,601,802; 5,607,924; and 5,622,946; PCT publications WO 90/10633, 94/29316, 95/10307, 95/21845, 96/09315, 96/38461 and 96/40253; allowed U.S. patent application Ser. Nos. 08/484,551, 08/591,318 and 08/624,311; and pending U.S. patent application Ser. Nos. 08/657,947, 08/700,277 and 08/763,451; each patent, publication, and application is incorporated in its entirety herein by reference.
The present invention also provides for use of esters of 5-aminolevulinic acids or pharmaceutically acceptable salts thereof to treat pre-melanoma. These photosensitizers are described in U.S. Pat. No. 6,034,267 which is incorporated in its entirety herein by reference.
In esters of 5-aminolevulinic acids, the 5-amino group may be substituted or unsubstituted.
More particularly, the 5-aminolevulinic acids may be esters with optionally substituted alkanols, for example, alkyl esters or substituted alkyl esters. Database Xfire, entries 3060978, 5347132, 5499790, 5620924, 5633390, 5991317 and 6517740 (Beilstein); Cosmo Sogo Kenkyusho KK, Patent Abstracts of Japan, Vol 16; No. 156 (C-0930), 16.4.1992; EP-A-316179 (Tokuyama Soda KK); GB-A-2058077 (Hudson et al) and DE-A-2411382 (Boehringer Sohn Ingelheim) describe alkyl ester derivative of 5-aminolevulinic acid, and derivatives and salts thereof and processes for their preparation.
The invention may therefore be seen to provide for the use of compounds of formula I
R22Nxe2x80x94CH2COCH2xe2x80x94CH2COxe2x80x94OR1xe2x80x83xe2x80x83(formula I)
salts thereof and mixtures thereof, wherein R1 and R2 may represent an alkyl optionally substituted by hydroxy, alkoxy, acyloxy, alkoxycarbonyloxy, amino, aryl, oxo or fluoro groups and optionally interrupted by oxygen, nitrogen, sulfur or phosphorus atoms and R2 may represent a hydrogen atom. Each R2 may be the same or different.
The substituted alkyl groups may be mono or poly-substituted. Thus, suitable groups include, for example, unsubstituted alkyl, alkoxyalkyl, hydroxyalkoxyalkyl, polyhydroxyalkyl, hydroxy poly alkyleneoxyalkyl and the like. The term xe2x80x9cacylxe2x80x9d as used herein includes both carboxylate and carbonate groups, thus, acyloxy substituted alkyl groups include for example alkylcarbonyloxy alkyl. In such groups any alkylene moieties may have carbon atom contents defined for alkyl groups below. Certain aryl groups include phenyl and monocyclic 5-7 membered heteroaromatics, especially phenyl and such groups may themselves optionally be substituted. Representative substituted alkyl groups include alkoxymethyl, alkoxyethyl and alkoxypropyl groups or acyloxymethyl, acyloxyethyl and acyloxypropyl groups, for example, pivaloyloxymethyl.
Certain compounds for use according to the invention, include those wherein R1 represents an unsubstituted alkyl group and/or each R2 represents a hydrogen atom.
As used herein, the term xe2x80x9calkylxe2x80x9d includes any long or short chain, straight-chained or branched aliphatic saturated or unsaturated hydrocarbon group. The unsaturated alkyl groups may be mono- or polyunsaturated and include both alkenyl and alkynyl groups. Such groups may contain 1 to about 40 carbon atoms. Alkyl groups containing 1 to about 10 are commonly used. For example, 8, 6 or 4 carbon atoms may be used.
In certain embodiments, ALA-methylester, ALA-ethylester, ALA-propylester, ALA-hexylester, ALA-heptylester and ALA-octylester and salts thereof, represent certain compounds for use according to the invention. The compounds for use according to the present invention may take the form of pharmaceutically acceptable salts. Such salts may be acid addition salts with physiologically acceptable organic or inorganic acids. Suitable acids include, for example, hydrochloric, hydrobromic, sulfuric, phosphoric, acetic, lactic, citric, tartaric, succinic, maleic, fumaric and ascorbic acids. Procedures for salt formation are conventional and are well known in the art.
The esters of 5-aminolevulinic acid may exert their effects by enhancing production of Protoporphyrin IX (Pp); upon delivery to the desired site of action hydrolytic enzymes such as esterases present in the target cells break down the esters into the parent ALA, which then enters the haem synthesis pathway and leads to a build-up of Pp. The ester compounds may have advantages over ALAs. First, the compounds may better be able to penetrate skin and other tissues as compared with ALA; the penetration is both deeper and faster. This is an important advantage, especially for topical administration. Second, the esters have may be better enhancers of Pp production than ALA; Pp production levels following administration of the ALA esters are higher than with ALA alone. Third, the compounds may have improved selectivity for the target tissue to be treated, namely the Pp production-enhancing effect may be localized to the pre-melanoma and not spread to the surrounding tissues. Finally, the compounds may localize better to the pre-melanoma upon administration. This means that undesirable photosensitization effects may be reduced or avoided. The present invention provides for the use of the herein described compounds, or a pharmaceutically acceptable salt thereof, for use in the treatment and or detection of pre-melanoma.
The internal and external body surfaces which may be treated according to the invention include the skin and all other epithelial and serosal surfaces, including and any other area of the body where a pre-melanoma may exist.
Formulations
The compositions of the invention can be formulated in conventional manner with one or more physiologically acceptable carriers or excipients, according to techniques well known in the art. Compositions may be administered topically, orally or systemically. Topical compositions may be particularly useful in accordance with the present invention, and include gels, creams, ointments, sprays, lotions, salves, sticks, soaps, powders, pessaries, aerosols, drops and any of the other conventional pharmaceutical forms known in the art.
Photosensitizing agents can be more effective for photodynamic therapy when used as part of a formulated composition. For example, the agents may have better adhesion characteristics, may remain more stable in storage and through transportation, may be less susceptible to bacterial contamination, and may be readily applied.
Suitable formulations contain a sufficient amount of light photosensitive agent to be effective with photodynamic therapy. For example, see U.S. Pat. No. 5,179,120 which is incorporated in its entirety herein by reference.
Methods well known in the art for making formulations may be found in, for example, xe2x80x9cRemington""s Pharmaceutical Sciences.xe2x80x9d Formulations may contain, for example, as excipients sterile water or saline, Cremophor EL, polyalkylene glycols such as polyethylene glycol, oils of vegetable origin, or hydrogenated naphthalenes biocompatible, biodegradable lactide polymer, or polyoxyethylene-polyoxypropylene copolymers. Other potentially useful formulation components may include ethylene-vinyl acetate copolymer particles, osmotic pumps, implantable infusion systems, liposomes, and antibody conjugates.
Formulations for inhalation may contain as excipients, for example, lactose, or may be aqueous solutions containing, for example, polyoxyethylene-9-lauryl ether, glycocholate and deoxycholate, or may be oily solutions for administration in the form of nasal drops, or as a gel to be applied intranasally.
Formulations for parenteral administration may also include glycocholate for buccal administration, methoxysalicylate for rectal administration, or citric acid for vaginal administration.
Topical formulations may be prepared in gel form by combining the photophotosensitive agent with a solvent and adding a gelling agent thereto. Suitable gelling agents include carboxymethyl cellulose (Carbopol.TM. 934P from B. F. Goodrich of Brecksville, Ohio U.S.A.) and fumed silica (CAB-O-SIL(copyright), Cabot Corp., Tuscola, Ill.). The gelling agent is generally used in amounts of about 5-10 wt % to obtain a gel with the desired viscosity. Obviously, gels containing more or less gelling agent will have slightly higher or lower viscosity. One skilled in the art may readily obtain the desired gel viscosity by adjusting the concentration of gelling agent.
Additives, such as cosolvents, surfactants and/or bioadhesives frequently improve the formulation properties and may be added as desired. Suitable cosolvents/surfactants include propylene glycol and glycerine. Suitable bioadhesives include carboxymethylcellulose, polyacrylic polymers, chitosan and sodium alginate, modified starch with polyacrylic polymers, eudispert hv hydrogels or xerogels, sodium hyaluronate, and polymers of polyethylene glycol, hydroxypropylcellulose, or carboxyvinyl. The additives may be incorporated into the formulation by mechanically mixing the additives into the mixture. Other additives may be used to enhance or maintain chemical stability and physiological suitability. Examples are antioxidants, chelating agents, inert gases, buffers and isotonicifiers.
Examples of antioxidants and typical concentration ranges include acetone sodium bisulfite (about 0.1% to about 2%), ascorbic acid (about 0.05% to about 5%), monothioglycerol (about 0.1% to about 10%), potassium metabisulfite (about 0.05% to about 1%), propyl gallate (about 0.02%), sodium bisulfite (about 0.01% to about 1.0%), sodium formaldehyde sulfoxylate (about 0.03% to about 1%), sodium metabisulfite (about 0.02% to about 1%), sodium sulfite (about 0.01% to about 1%), sodium thioglycolate (about 0.05% to about 1%).
Chelating agents may beneficially be included in order to enhance accumulation of Pp; the chelation of iron by the chelating agents may prevent incorporation of iron into Pp to form haem by the action of the enzyme ferrochelatase, thereby leading to a build-up of Pp. The photosensitizing effect is thus enhanced.
Examples of chelating/complexing agents and example concentration ranges include edetate sodium (about 0.005% to about 2%), edetate calcium disodium (about 0.005% to about 0.01%), gentisic acid ethanolamide (about 1.0% to about 2.0%), niacinamide (about 1.0% to about 5%), sodium citrate (about 0.01% to about 5%), citric acid (about 0.001% to about 1.0%). However, a chelating agent may conveniently be used at a concentration of about 0.1% to about 40% (w/w), for example, about 2% to about 10% (w/w). Aminopolycarboxylic acid chelating agents are useful in the present invention. These include any of the chelants described in the literature for metal detoxification or for the chelation of paramagnetic metal ions in magnetic resonance imaging contrast agents. Particular mention may be made of EDTA, CDTA (cyclohexane diamine tetraacetic acid), DTPA and DOTA. To achieve the iron-chelating effect, desferrioxamine and other siderophores may also be used, for example, in conjunction with aminopolycarboxylic acid chelating agents such as EDTA.
Buffers may be used to stabilize a formulation. Buffer systems employed normally have as low a buffer capacity as feasible in order to not disturb significantly the body buffer systems if injected.
The buffer range and effect of the buffer on activity may be evaluated. Appropriate adjustment may be useful to provide the optimum conditions for pH dependent partition into the target malignant tissues or pre-melanoma area. Examples of such buffer systems include the following acids: acetic, adipic, ascorbic, benzoic, citric, glycine, lactic, tartaric, hydrochloric, phosphoric, sulfuric, carbonic and bicarbonic; and their corresponding salts such as: potassium, sodium, magnesium, calcium and diethanolamine salts. A surface-penetration assisting agent may be any of the skin-penetration assisting agents described in the pharmaceutical literature e.g. HPE-101 (available from Hisamitsu), DMSO and other dialkylsulphoxides, in particular n-decylmethyl-sulphoxide (NDMS), dimethylsulphacetamide, dimethylformamide (DMFA), dimethylacetamide, glycols, various pyrrolidone derivatives (Woodford et al., J. Toxicol. Cut. and Ocular Toxicology, 1986, 5: 167-177), and Azone(copyright) (Stoughton et al., Drug Dpv. Ind. Pharm. 1983, 9: 725-744.
DMSO has a number of beneficial effects. Thus, in addition to the surface-penetration assisting effect (DMSO is particularly effective in enhancing the depth of penetration of the active agent into the tissue), DMSO has anti-histamine and anti-inflammatory activities. In addition, DMSO has been found to increase the activity of the enzymes ALA-synthase and ALA-dehydrogenase (the enzymes which, respectively, form and condense ALA to porphobilinogen) thereby enhancing the formation of the active form, Pp.
The surface penetration agent may conveniently be provided in a concentration range of about 2% to about 50% (w/w), for example, about 10% (w/w).
Some other surface penetration agents are proparacaine, dimethyl sulfoxide, dimethyl acetamide, dimethylformamide, 1-methyl-2-pyrrolidone, diisopropyladipate, diethyltoluamide and to a lesser extent propylene glycol. Additional penetration agents include substituted azacycloalkan-2-ones having from 5 to 7 carbons in the cycloalkyl group such as 1-dodecylazacycloheptan-2-one (AZONE) and other azacycloalkan-2-ones such as described in U.S. Pat. No. 3,989,816 incorporated herein in its entirety by reference. Also included are N-bis-azocyclopentan-2-onyl alkanes described in U.S. Pat. No. 3,989,815 (incorporated herein by reference), 1-substituted azacyclopentan-2-ones described in U.S. Pat. No. 3,991,203 (incorporated herein by reference) and water-soluble tertiary amine oxides described in U.S. Pat. No. 4,411,893 (incorporated herein by reference).
The topical formulations contain a sufficient amount of the photosensitizing compound to be effective in photodynamic therapy. Generally, concentrations in the range of about 0.001% to about 70%, for example, from about 1% to about 20%, may be used.
The photosensitizing agents may be used with solvents and adjuvants which are appropriate to the photosensitive agent chemistry to adjust the viscosity of the formulation. Some solvents that may be used for this purpose are ethanol, polyethylene glycols of the liquid series and propylene glycol. Also included are acetone, dimethyl acetamide, dimethyl formamide, dimethyl sulfoxide ethanol, glycerin, polyethylene glycol 300, and 400, propylene glycol, sorbitol, polyoxyethylene sorbitan fatty acid esters such as laureate, palmitate, stearate, and oleate, polyoxyethylated vegetable oil, sorbitan monopalmitate, 2-pyrrolidone; n-methyl-2-pyrrolidine; n-ethyl-1-pyrrolidine; tetrahydrofurfuryl alcohol, tween 80 and dimethyl isosorbide. Dimethyl isosorbide (ARLASOLVE(copyright) DMI, ICI Specialty Chemicals) has the advantage of being both water- and oil-soluble. Additionally, dimethyl isosorbide may be readily gelled with a gelling agent or mixed with lotion, cream or ointment to produce formulations with, for example, about 4% KLUCEL(copyright) (Hercules).
Additional topical formulations which may be used for chosen photosensitive agents are disclosed in U.S. Pat. Nos. 3,592,930 and 4,017,615 which are incorporated herein by reference. In certain formulations, the photosensitive agent is applied in an aqueous gel, lotion, cream or ointment formulation suitable for use on sensitive tissues. Such formulations may contain one or more bioadhesive polymers. The formulation may have a viscosity within the range from about 26,000 to about 1,500,000 cps at 20xc2x0 C. and a pH and/or isosmotic make-up compatible with body tissues.
The compositions may also be provided in a form adapted for, for example, oral administration, parenteral administration, administration by injection, for example, by intradermal, subcutaneous, intraperitoneal or intravenous injection. Alternative pharmaceutical forms thus include plain or coated tablets, capsules, suspensions and solutions containing the active component optionally together with one or more inert conventional carriers and/or diluents, for example, with corn starch, lactose, sucrose, microcrystalline cellulose, magnesium stearate, polyvinylpyrrolidone, citric acid, tartaric acid, water, water/ethanol, water/glycerol, water/sorbitol, water/polyethyleneglycol, propyleneglycol, stearylalcohol, carboxymethylcellulose or fatty substances such as hard fat or suitable mixtures thereof.
The concentration of the compounds as described herein in the compositions, depends upon the nature of the compound, the composition, mode of administration and the patient and may be varied or adjusted according to choice. Generally however, concentration ranges of about 1% to about 90% (w/w) may be suitable, for example, about 10% to about 30% (w/w).
According to the condition being treated, and the nature of the composition, the compounds for use in the invention may be co-administered with the herein described formulation agents, for example, in a single composition, or they may be administered sequentially or separately. In many cases a particularly beneficial photochemotherapeutic effect may be obtained by pre-treatment with a surface-penetration assisting agent in a separate step, prior to administration of the compounds for use in the invention. Furthermore, in some situations a pre-treatment with the surface-penetration assisting agent, followed by administration of the photochemotherapeutic agent in conjunction with the surface-penetration assisting agent may be beneficial. When a surface-penetration assisting agent is used in pre-treatment, it may be used at a low to high concentration, for example, from about 0.1% to about 100% (w/w).
Methods of Use
A topical photosensitive agent may be applied to tissues that may contain a pre-melanoma one time or more, for example, 1 to 50 times or more a day for 1 to 20 days or more.
Following administration to the surface, the area treated may be exposed to light to achieve the photochemotherapeutic effect. In certain embodiments of the invention, the methods include a waiting step before the step of activating the photosensitizer. The waiting step is designed to allow the photosensitizer to reach an optimal tissue concentration at the pre-melanoma site, prior to photoactivation. If a waiting step is used, the length of the waiting step will depend on factors such as the route by which the photosensitizer is administered, the location of the pre-melanoma, and the speed with which the photosensitizer moves in the body. The waiting step may be, for example, about 1 second to about 0.5 h or about 0.5 h to about 1 h or about 1 h to about 24 h or about 1 day to about 50 days.
Light may be used to activate the photosensitizer. The size of the light coverage and duration of the exposure may be adjusted depending on the dimensions and location of the pre-melanoma. The specific size and duration of exposure may depend on the strength of the laser being used, the diameter of the pre-melanoma and the presence or absence of pigmentation. Methods for irradiation of different areas of the body by, for example, lamps or lasers are well known in the art (see, for example, Van den Bergh, Chemistry in Britain, May 1986 p. 430-439).
After application of the photosensitizer to a pre-melanoma the pre-melanoma site may be exposed to light of an effective wavelength and effective intensity, for an effective length of time. What wavelength, or range of wavelengths, is effective may depend on the photosensitizer(s) used. Wavelength specificity for photoactivation may depend on the molecular structure of the photosensitizer
Delivery of the light used to photoactivate the photosensitizer may be limited to the pre-melanoma site or the pre-melanoma site plus an area surrounding the pre-melanoma site. This may minimize undesirable cytotoxic side effects.
The light for photoactivation may be produced and delivered to the pre-melanoma site by any suitable means. Some photosensitizer compounds may be activated by near infrared and longer wavelength visible light. This allows deeper tissue penetration of the photoactivating light, thereby facilitating transillumination. Transillumination may be performed using a variety of devices. The devices may utilize laser or non-laser sources, for example, lightboxes or convergent light beams.
The irradiation will in general be applied at a dose level of about 1 to about 500 Joules/cm2, for example at about 100 Joules/cm2. A higher or lower dose level can be used as determined by a treating physician.
The applied energy level may also be adjusted by the number of times the energy is applied. The specific number of such energy applications will depend on the pre-melanoma. Some pre-melanomas may require 200 energy applications to reach an effective therapy, others only 1-50 energy applications, while others may need 3-4 sessions of 100 energy applications each. The number of energy applications used may be determined by a treating physician.
A laser energy delivered to the pre-melanoma per light burst in the present invention may be within the range from about 1 Joule/cm2 (J/cm2) to about 9000 J/cm2, for example, within the range from about 1-900 J/cm2, for example, within the range from about 5 J/cm2 to about 500 J/cm2. Typical treatments may involve anywhere from 1 to 4000 applications of laser energy to a pre-melanoma.
An aspect of the invention provides a method of photochemotherapeutic treatment of pre-melanoma of external or internal surfaces of the body, comprising administering to the affected surfaces, a composition as hereinbefore defined, and exposing said surfaces to light, for example, to light in the wavelength region 300-800 nm, for example 500-700 nm. The wavelength of light used for irradiation may be selected to achieve a more efficacious photochemotherapeutic effect. In one embodiment, when porphyrins are used in photochemotherapy they are irradiated with light at about the absorption maximum of the porphyrin. For example, use of ALA in photochemotherapy, wavelengths in the range of about 350 to about 640 nm, for example, about 610 to about 635 nm may be employed. However, by selecting a broad range of wavelengths for irradiation, extending beyond the absorption maximum of the porphyrin, the photosensitizing effect may be enhanced. Not wishing to be bound by any theory or mechanism of operation, this is thought to be due to the fact that when Pp, and other porphyrins, are exposed to light having wavelengths within its absorption spectrum, Pp is degraded into various photo-products included in particular photoprotoporphyrin (PPp). PPp is a chlorin and has a considerable photo-sensitizing effect; its absorption spectrum stretches out to longer wavelengths beyond the wavelengths at which Pp absorbs, for example, up to about 700 nm (Pp absorbs almost no light above 650 nm). Irradiation with wavelengths of light in the range 500-700 nm may be particularly effective. It may be particularly important to include the wavelengths 630 and 690 nm.
Light Sources
Light in a plurality of bursts from a laser may be applied to one or more pre-melanomas. On outer cutaneous, ocular, and buccal surfaces, the energy may be applied directly. Internal surfaces may require appropriate speculum retraction or endoscopic delivery. Fiber optic lasers may be used to deliver the energy with a high degree of precision.
Conventional monochromatic light sources may be used in the present invention by matching the wavelength of the emitted light to the sensitizing wavelength of the photosensitizing agents. Examples include monochromatic light from traditional Argon lasers, tunable dye lasers, pulsed metal vapor lasers (e.g., gold vapor, copper vapor pumped dye lasers, Nd:YAG pumped dye lasers), and solid-state lasers. The traditional argon laser is recognized as a standard, readily available laser used in virtually all clinics and hospitals.
The invention having been fully described, examples illustrating its practice are set forth below. These examples should not, however, be considered to limit the scope of the invention, which is defined by the appended claims.


Methods and systems for rapidly and conveniently creating prescriptions through the use of portable digital assistants (PDAs) and bar code scanning technology are provided. Prescriptions are created using a form-based approach in which prescribing options are presented to the prescriber for selection. The system allows entry of medication and patient ID by scanning bar codes. A bar code is generated for each prescription and is used to access the prescription information in a database. The bar code and prescription information can be printed on a ticket, which can be presented at a pharmacy when the prescription is picked up. The use of bar codes allows several levels of checking to ensure that the correct medication is dispensed and that the prescription is valid. Prescription information is transmitted between prescribers and pharmacies via a central site at which prescription information is stored. In a preferred embodiment of the invention communication occurs over the Internet, and the creation and transmission of prescriptions are coordinated by a World Wide Web service which sends Web pages to PDAs to present and gather prescription information. The Web pages can provide links to patient and medication information, and the system can advise the prescriber if there is a contraindication to the medication about to be prescribed. The Web service transmits prescription information to pharmacies, receives notification when prescriptions are fulfilled, and can perform other functions such as notifying patients or physicians when prescriptions are close to running out. The Web service can further be used to keep track of medication sample package inventories at prescribing locations such as physician offices. Prescription data can be used to perform market research in a timely fashion.

In most areas of modern medical practice a typical physician is likely to prescribe a variety of medications on a daily basis. Unlike many areas of medicine, for example medical imaging, that have incorporated sophisticated computer technology with resulting improvements in patient care, the issuing of prescriptions has remained primarily a manual task. Yet issuing prescriptions is one of the most important and ubiquitous tasks of the physician. It is estimated that over two thirds of all physician-patient encounters culminate with the writing of a prescription.
After obtaining relevant historical information from a patient, performing a physical examination along with appropriate laboratory tests and possibly consulting the patient's medical record, the physician arrives at a diagnosis or at least an evaluation of the patient's condition. Following this process the physician typically selects one or more medications with the goal of treating the patient's condition and/or relieving symptoms. In making the selection, the physician utilizes patient-specific information including past medical history, current condition and concurrent medications, possible contraindications and potential drug interactions. The physician also relies on his or her preferences based on past experience with various medications and also on new information such as that provided by drug industry representatives and recent scientific research.
In addition to choosing the medication, the physician must also select a dosage amount, dosing time, and route of administration. The physician must sign the prescription and provide his/her license number, thereby confirming that the prescription was written by an authorized prescriber. The process of writing prescriptions varies somewhat depending upon the clinical setting. For example, in hospitals an order to administer a drug may be written directly in a patient's chart or entered into a computerized, hospital-based medical order system. The order is transmitted to the hospital pharmacy either directly or by a nurse, and the medication is administered to the patient by a nurse.
Far more typically prescriptions are written in an outpatient setting. The information that the physician must include on the prescription includes patient identification, medication name, dosage amount, timing, total amount of medication to be given to the patient, information regarding refills, physician's signature and license number, date, and possibly brief instructions and/or warnings. Optionally the physician can indicate that a brand name medication is to be dispensed as written, i.e., that the pharmacist should not substitute a generic medication. In the absence of such an indication the pharmacist is free to substitute a generic medication for a branded drug. Prescription information is typically written on a small piece of paper which may be preprinted with the physician's name and/or place of work. The patient presents the written prescription to a pharmacy for fulfillment. The pharmacist then fills the prescription, generating a label listing the name of the drug along with instructions to the patient regarding when to take the medication and how much to take each time.
The writing and transmission of prescriptions in a timely and accurate manner is of the utmost importance. Unfortunately, the system as described above has significant shortcomings. Firstly, it relies upon the handwriting of physicians, which is notoriously poor. If a pharmacist is unable to correctly interpret the medication name, dosage information, etc. written by the physician, there is a chance that the wrong medication will be given to the patient. To prevent such mishaps pharmacists frequently must contact the physician by phone to confirm the necessary information. It has been estimated that as many as ten percent of written prescriptions result in such "callbacks", representing a waste of physician and pharmacist time and introducing an opportunity for error if the physician cannot accurately recall exactly what he or she originally wrote. Callbacks also result in patient inconvenience and delay in obtaining necessary medication. Another drawback of the current system is the opportunity for fraudulent prescribing. In many health care settings there are few safeguards on the availability of "official-looking" prescription pads, and it is relatively easy for unauthorized persons to obtain them and write prescriptions, as long as these persons are able to learn a physician's license number. Pharmacists typically have no means of verifying that the signature on a prescription indeed belongs to an authorized prescriber. Furthermore, pharmacists have no way of verifying that the prescription information has not been altered, e.g., by changing the number of pills to be dispensed. There exists a need for methods and systems that will reduce or eliminate problems associated with inability to read physician handwriting on prescriptions. There further exists a need to minimize opportunities for fraud associated with prescription filling.
Computer-based systems for entering prescriptions can provide a number of advantages including minimizing problems with physician handwriting and potential fraud. In today's time and cost conscious environment, computer-based prescription and management can also offer significant improvements in efficiency. Furthermore, if connected to databases containing patient records, they can alert the physician if the patient has previously experienced an allergic reaction to a particular medication or has a contraindication to that medication. If connected to databases containing drug information, they can alert the physician to possible drug interactions and contraindications. It is recognized that a significant number of adverse patient experiences result from avoidable medication errors. Accordingly, there exists a need for improved methods and systems for checking that medications are prescribed appropriately.
Despite the advantages mentioned above, there are several barriers to the adoption of computer-based prescription entry. Physicians are highly mobile, often engaged in professional activities at multiple geographically distinct locations. They are frequently involved in patient encounters in sites such as examination rooms, hospital rooms, specialist areas such as imaging suites, etc., where they may not have access to a computer terminal. Small notebook computers, which a physician could transport, would theoretically eliminate the problem of limited access to terminals. However, given that physicians frequently already carry about diagnostic equipment, pocket references, etc., it is unlikely that they would embrace the notion of adding a notebook computer to their burden. Furthermore, such computers must often be plugged into wall jacks in order to electronically transmit information over a computer network. In addition, physicians are increasingly being consulted about patients over telecommunications equipment such as cellular phones and in settings in which use of either a traditional or notebook computer is impractical.
In order for a computer-based system to be widely adopted it must rival the current format of the written prescription in terms of rapidity and ease of use. At present, a physician can write a prescription by hand literally within seconds, at any time or place. Prescriptions are typically written at the termination of a patient encounter. With the increasing pressure on physicians to see more and more patients, it is typical for the end of the encounter to be very rushed, particularly if the physician feels that he or she has fallen behind the planned schedule. Most experienced physicians have long since memorized names, doses, etc., for medications that they prescribe frequently. Physicians will not be willing to adopt a system that requires a time-consuming selection process or that constrains them to enter information other than that necessary for appropriate completion of the prescription. They will not be willing to scroll through long lists of drugs, doses, and formulation options, or to laboriously enter drug names on a miniature keyboard. Thus despite the advantages of computer based prescription entry, it has not been widely adopted, particularly in outpatient settings and independent private practices. There exists a need for a streamlined, user-friendly electronic prescription entry system that will offer convenience that rivals or exceeds the traditional handwritten prescription in terms of ease of use for the prescriber.
Although prescriptions are generally written by physicians and filled by pharmacists, both providers and the patient population rely upon the activities of pharmaceutical manufacturers to ensure that medications will be available for dispensing. In a broader sense, the health care community and the population as a whole rely upon pharmaceutical companies to develop and introduce new and effective medications and to appropriately inform both groups as to the availability and advantages of these new medications. Through scientific publications, advertising both to the medical community and increasingly to the public, and through the distribution of free drug samples to physicians, pharmaceutical companies provide relevant and timely information about their products.
It is common practice for pharmaceutical sales representatives to distribute free drug samples to physicians, who in turn can give them to their patients. Distribution of free samples serves a number of important roles. The presence of these samples alerts the physician to the availability of a new drug, encouraging him to consider whether it might offer an improvement over the treatments he is currently prescribing. Patients can take the drug on a trial basis without needing to purchase it, thus avoiding the possibility that a patient will end up paying for a drug that is not effective for his condition. Physicians can gain experience with the medication, which may lead them to recommend its addition to hospital formularies.
Currently most distribution of free samples is done when a sales representative visits a physician, typically at the location of his practice. The representative gives the physician a certain number of free samples and typically writes down the number of samples of each medication distributed. Much like a physician, sales representatives are highly mobile and rely on the convenience of a traditional pen/pencil based system to record their transactions rather than using a desktop or notebook computer. To work properly, however, the present system requires that the sales representative manually maintains organized, up-to-date records of when and where he distributed sample and what lot numbers he distributed to a particular physician or site. In addition, the current system does not provide any means by which a sales representative can determine how much of the material distributed has been used. Thus physicians may run out of samples before the next time the representative visits. There exists a need for an improved system by which sales representatives and pharmaceutical manufacturers can record and track sample distribution and usage.
To operate effectively in today's competitive marketplace and to respond rapidly to new opportunities and demands, pharmaceutical companies need to be able to track the number of prescriptions written for the medications they produce. Present means to obtain this type of data rely on retrospective surveys and often result in incomplete data available only months after the relevant prescribing activity has taken place. Thus there exists a need for a system whereby pharmaceutical manufacturers can obtain timely information regarding the usage of their products.

Wireless electronic prescription scanning and management system


Biocompatible diphasic compositions are prepared comprising a dispersed phase suspended in a continuous phase, more particularly suitable for use as a filling material in reparative and plastic surgery. The dispersed phase consists of particles of at least one hydrogel of a (co)polymer obtained by polymerizing and cross-linking acrylic acid, methacrylic acid and/or at least one derivative of said acids. The continuous phase is an aqueous solution or hydrogel of a polymer selected from proteins, polysaccharides and their derivatives which have been cross-linked. The polysaccharide may be hyaluronic acid, its salts and a mixture of its salts, advantageously consisting of a sodium hyaluronate.

The present invention has for its principal object diphasic injectable compositions, in particular useful in reparative and plastic surgery. It has more precisely for object:
biocompatible diphasic compositions comprising a dispersed phase in suspension in a continuous phase;
a method for preparing said compositions;
a filling material useful in reparative surgery and in plastic surgery, based on said diphasic compositions.
The present invention proposes in particular a satisfactory solution to the technical problem of durable filling of the defects of volume of the skin, such as wrinkles or scars, particularly on the face.
With reference to this technical problem, different approaches and in particular different diphasic injection compositions have already been proposed according to the prior art.
As from 1970, Jaime Planas had the idea to make particles of silicone, in order to inject them under the skin.
More precisely, it has been described:
in EP-A-0 406 375: an alloplastic implant based on a histocompatible solid: said pulverulent solid being constituted by solid particles of diameter included on average between 10 xcexcm and 200 xcexcm, and which present a smooth surface having no angle nor edge. A product which corresponds to this Patent Application is found at present on the market. Said product, marketed under the Trademark Artecoll(copyright), consists of microspheres of polymethacrylate (PMMA) in suspension in a collagen solution;
in EP-A-0 466 300: a viscoelastic gel comprising a gelatinous phase (having undergone a low-rate cross-linking) dispersed in a liquid phase (not having undergone cross-linking); said two phases advantageously having been prepared from fibers of Hylan (natural hyaluronic acid chemically modified in situ for the purpose of facilitating extraction thereof from the tissues);
in U.S. Pat. No. 5,137,875: injectable solutions or dispersions of collagen, containing hyaluronic acid in solution;
in WO-A-96 33751: diphasic compositions capable of containing in their continuous and dispersed phases hyaluronic acid or one of its salts; said acid or salt intervening, xe2x80x9crelativelyxe2x80x9d cross-linked in the form of fragments, in order to constitute the dispersed phase, and in aqueous solution, not or very little cross-linked, in order to constitute the continuous phase. It is provided to employ in said continuous phase, in combination or in place of said hyaluronic acid or one of its salts, another biocompatible polymer selected from proteins, polysaccharides and derivatives thereof.
Furthermore, a product, of the diphasic composition type, would be evaluated in the United States. It is principally constituted by silicone balls, dispersed in a solution of polyvinylpyrrolidone.
Incidentally, it will be noted here that documents EP-A-826 381, FR-A-2 568 127, U.S. Pat. No. 4,657,553 and U.S. Pat. No. 4,563,490 do not describe diphasic compositions.
There are therefore numerous variants of diphasic compositions, useful in reparative and plastic surgery and it does not appear obvious to develop one of them, optimalized with reference to the numerous parameters consisting of:
the exact nature and form of the continuous phase;
the nature, form, surface state . . . of the dispersed phase.
In such a context, Applicants propose a novel type of diphasic composition which shows particularly high-performance.
The biocompatible diphasic composition of the type of the invention therefore includes a dispersed phase suspended in a continuous phase and, characteristically, said dispersed phase consists of particles of at least one hydrogel of a (co)polymer obtained by polymerizing and cross-linking acrylic acid and/or methacrylic acid and/or at least one derivative of said acids.
The diphasic compositions of the invention are injectable compositions. They have been formulated with this in view. It is particularly for that purpose that they contain a continuous phase; said phase serving as injection vehicle for the particles of the dispersed phase.
The term injectable used in the present text means manually injectable by means of syringes provided with conventional needles. The diphasic compositions of the invention are particularly interesting in that they can be formulated to be injectable by means of very fine needles (with a diameter included between 0.3 and 0.5 mm). The person skilled in the art understands that the determining parameter is that of the largest dimension of the particles in suspension. Within the framework of the present invention, it is in particular possible to formulate compositions injectable through hypodermic needles of 30 G xc2xd, 27 G xc2xd, 26 G xc2xd, 25 G. Said compositions constitute the most advantageous variant of the compositions of the invention.
The injectable diphasic compositions of the invention are more particularly intended for dermic injection (superficial, mean or deep) for an implantation in the dermis. To that end, for the purpose of eliminating any unpleasant feeling or any pain during their injection and during their implantation, they are advantageously buffered at a pH included between 6.5 and 7.5, preferably included between 7 and 7.4, and preferably still, between 7.2 and 7.3.
In this way, the two continuous and dispersed phases of said diphasic compositions are advantageously buffered at that pH.
A phosphate buffer is generally employed.
The diphasic compositions of the invention therefore comprise an original dispersed phase as specified hereinabove, suspended in an adequate continuous phase.
Said continuous phase must, in effect, be capable of performing several functions, and in particular:
a) it must maintain the dispersed phase in suspension, in stable manner,
b) it must constitute a high-performance injection vehicle,
c) after injection and implantation of the diphasic composition, it must advantageously protect said dispersed phase (in particular prevent it from migrating and promote the formation of fibroblasts around its particles, which slows down degradation thereof).
With reference to points a and b, it will be understood that a compromise must be adopted. Said continuous phase must be sufficiently fluid to be able to be easily injected, and sufficiently viscous to avoid decantation of the dispersed phase.
The compromise mentioned hereinbefore may be obtained with different types of continuous phase. Within the framework of the invention, certain types, specified hereinafter, are largely preferred.
We now propose to give precisions on each of the phasesxe2x80x94continuous phase, dispersed phasexe2x80x94of the diphasic compositions of the invention.
By way of continuous phase, an aqueous solution of at least one polymer selected from proteins, polysaccharides and their derivatives, cross-linked or not, is advantageously employed. Said polymer, depending on its nature, in order to perform the above-recalled functions, is capable of intervening not cross-linked, slightly cross-linked or strongly cross-linked. Collagen, albumin, elastin . . . may in particular be employed as protein; as polysaccharide or derivative of polysaccharide:hyaluronic acid, its salts, sulphates of chondroitine, keratane, heparin, alginic acid, starch, carboxymethylcellulose, chitosane.
The possible cross-linking of this type of polymer does not raise particular difficulties for the person skilled in the art.
It is more particularly recommended to employ xe2x80x9can aqueous solutionxe2x80x9d of a polymer selected from hyaluronic acid, its salts and mixtures of its salts; said polymer advantageously being cross-linked. In fact, according to a preferred variant, said continuous phase of the diphasic compositions of the invention is a hydrogel of a cross-linked polymer selected from hyaluronic acid, its salts and mixtures of its salts; said cross-linked polymer advantageously consisting of a sodium hyaluronate.
The term hyaluronic acid is used in the following text as generic name to designate both hyaluronic acid per se and its salts or mixtures of salts and in particular salts of hyaluronate. The diphasic compositions of the invention advantageously contain sodium hyaluronate in their continuous phase, by way of polymer selected from hyaluronic acid, its salts and mixtures of its salts. It is already specified that said sodium hyaluronate employed is advantageously of bacterial origin.
Said hyaluronic acid (or at least one of its salts) has been more especially retained in view of its advantageous properties. It may in particular be obtained by the bacterial route, by cellular route (therefore bereft of any contaminant of virus type or prions). It presents both a strong gelatinous nature, a noteworthy lubricating power, a good biocompatibility and a good hold in the organism. Moreover, it is easily cross-linkable.
Cross-linked, it is capable of presenting the viscosity required within the context of the invention and, in any case, it is more resistant to degradation and to heat (the latter point is not negligible insofar as the compositions of the invention are generally sterilized in an autoclave).
Characteristically, the continuous phase of the compositions of the invention is advantageously based on cross-linked hyaluronic acid. It is no longer really question of an aqueous solution but of a hydrogel. Said hyaluronic acid has been conventionally cross-linked with the aid of at least one cross-linking agent. In order to obtain a hydrogel containing a reasonable quantity of said cross-linking agent, it is recommended to use as starting material a hyaluronic acid whose molecular mass is greater than or equal to 1 million Daltons. According to an advantageous variant, it is recommended to use a hyaluronic acid whose molecular mass is included between 2 and 4 million Daltons. Furthermore, it is recommended to carry out said cross-linking via the hydroxy functions of the hyaluronic acid, by means of a cross-linking agent (at least one), under conditions which lead to a cross-linking rate of said hyaluronic acid (starting material) characterized by the ratio: total number of reactive functions of said cross-linking agent/total number of disaccharide repeating units of the molecules of hyaluronic acid present, included between 0.25 and 0.50.
In fact, the network of the hydrogel, which thus constitutes the continuous phase of the diphasic compositions of the invention, is based on molecules of hyaluronic acid joined by bridges of molecules of cross-linking agent; each of the disaccharide repeating units of said molecules of hyaluronic acid advantageously having between 0.25 and 0.50 of its hydroxy functions engaged in such bridges.
By way of cross-linking agent, any agent known for cross-linking the hyaluronic acid via its hydroxy functionsxe2x80x94at least bifunctional cross-linking agentxe2x80x94and in particular a polyepoxide or its derivatives, may be employed. By way of such cross-linking agent, the following may in particular by employed: epichlorhydrin, divinylsulfone, 1,4-bis-(2,3-epoxypropoxy)butane (or 1,4-bis(glycidyloxy)butane or 1,4-butanediol diglycidyl ether=BDDE), 1,2-bis-(2,3-epoxypropoxy)ethylene, 1-(2,3-epoxypropyl)-2,3-epoxy cyclohexane . . . It is not excluded from the scope of the invention to employ a plurality of cross-linking agents . . . It is more particularly recommended to employ 1,4-butanediol diglycidyl ether (BDDE).
The person skilled in the art knows, in any case, how to master the cross-linking of hyaluronic acid.
The hydrogel constituting the continuous phase of the diphasic compositions of the invention, based on cross-linked hyaluronic acid, advantageously contains said cross-linked hyaluronic acid at a concentration included between 10 and 25 mg/g, advantageously between 15 and 25 mg/g. It may be specified here, in non-limiting manner, that said hydrogel in fact generally contains more than 95% by weight of water . . .
Incidentally, it is recalled here that the hyaluronic acid, from which the hydrogel constituting the continuous phase of the diphasic compositions of the invention is preferably elaborated, is advantageously obtained by the bacterial route (rather than by extraction from animal tissues, cockscomb and umbilical cords in particular . . . ) and that it is more particularly recommended to use a sodium hyaluronate. In fact, for elaborating said hydrogel the intervention of fibers of sodium hyaluronate, obtained by the bacterial route, is more particularly recommended.
The dispersed phase consists of particles of at least one hydrogel of a (co)polymer obtained by polymerizing and cross-linking acrylic acid and/or methacrylic acid and/or at least one derivative of said acids.
The size of said particles is conventionally more or less defined, insofar as:
they must not be too small: in such a hypothesis, they would be rapidly eliminated by the giant cells or the macrophages, they would migrate too easily and might thus develop a carcinogenic effect, and
neither must they be too voluminous: in such a hypothesis, difficulties would be encountered in injecting them through hypodermic needles (such as needles 30 G xc2xd which present an internal diameter of 160 xcexcm) and it is possible that they would not suit for filling wrinkles of small size . . . It will be noted here that, concerning the maximum size of said particles, their deformability which is more reduced in view of the material constituting them, than that of particles of other types, will be taken into account.
The largest dimension of said particles is generally included between 10 and 120 xcexcm, advantageously between 20 and 80 xcexcm.
One speaks of the largest dimension of said particles (i.e. of their equivalent diameter) insofar as it is advantageously question of fragments of hydrogel which present a rough surface, fragments of hydrogel generally obtained by crushing a mass of hydrogel.
It is in no way expressly excluded from the scope of the invention to employ particles with symmetry of revolution, presenting a smooth surface, bereft of angle and edge, but it is preferred by far to employ fragments such as specified hereinabove, fragments that may be obtained easily and which, a priori, present two advantages:
a smooth implant surface has greater risks of provoking the formation of tumours than a rough surface (Prog. Exp. Tumor Res., Vol. 5, pages 85-133: xe2x80x9cCarcinogenesis through solid state surfacesxe2x80x9d by F. BISCHOFF and G. BRYSON);
a granulous particle surface promotes the growth of the fibrous tissues around, thus fixing the particles on the site of injection and avoiding their migration (Cosmetics, Vol. 100, No. 6, pages 1570-1574: xe2x80x9cBioplastique at 6 yearsxe2x80x9d, by ERSEK R. A., GREGORY S. R. and SALISBURY M. D.).
The fragments constituting the dispersed phase of the compositions of the invention may in fact present totally random shapes and in particular oval, rounded, triangular, square geometries . . . and even the form of sticks.
Said particles are particles of hydrogel. In that, they are in particular less traumatizing than particles of PMMA type of the prior art.
Said particles generally present, at equilibrium, a water content included between 10 and 40% by weight, advantageously close to 25% by weight.
Said hydrogel is a hydrogel of a methacrylic and/or acrylic, cross-linked, hydrophilic polymer or copolymer. It is obtained by polymerizing and cross-linking at least one monomer selected from acrylic acid, methacrylic acid and their derivatives.
Said hydrogel is advantageously obtained from at least one monomer selected from
It will obviously be understood that, insofar as said (meth)acrylic (co)polymer must be hydrophilic (in order to constitute said hydrogel), it is excluded that it be question of a methyl polymethacrylate (PMMA). When said methyl methacrylate (MMA) intervenes, it forcibly intervenes by way of comonomer.
The (meth)acrylic hydrophilic (co)polymer constituting the particles of the dispersed phase of the diphasic compositions of the invention, advantageously consists of cross-linked hydroxyethyl polymethacrylate (PHEMA) or, even more advantageously, of a cross-linked copolymer:
of hydroxyethyl methacrylate (HEMA) and
of ethyl methacrylate (EMA).
Said hydroxyethyl methacrylate (HEMA) gives the particles of the dispersed phase hydrophily and suppleness while said ethyl methacrylate (EMA) optimalizes their mechanical properties. The quantity of intervention of said EMA must obvously remain within reasonable limits in order not to compromise the hydrophilic nature of the copolymer. It is specified here that said copolymer is advantageously obtained by copolymerization, for 100 parts by weight of monomers: HEMA+EMA, of 77.5 to 87.5 parts by weight (advantageously from 80 to 85 parts by weight) of HEMA and 12.5 to 22.5 parts by weight (advantageously from 15 to 20 parts by weight) of EMA. According to a particularly advantageous variant, it is obtained by copolymerization of 82.5 parts by weight of HEMA and 17.5 parts by weight of EMA.
In this way, the methacrylic copolymer which constitutes the particles of the dispersed phase of the diphasic compositions of the invention contain repeating units [HEMA] and repeating units [EMA] in a ratio R:R=[HEMA]/[HEMA], generally included between 3.0 and 6.1, advantageously included between 3.5 and 5 and, according to a preferred variant, being 4.1.
Said poly[HEMA/EMA] copolymer is, as specified hereinabove, cross-linked. Such a cross-linking is indispensable to ensure cohesion of the material and its stability. An (at least one) cross-linking agentxe2x80x94bifunctionalxe2x80x94must therefore intervene, in an efficient quantity, during copolymerization of the HEMA and EMA monomers. This efficient quantityxe2x80x94generally, at maximum, some parts by weight: in principle included between 0.5 and 5 parts by weight, advantageously included between 0.5 and 2 parts by weight, for 100 parts by weight of HEMA+EMA monomersxe2x80x94must obviously remain reasonable. It is not a question of the intervening cross-linking agent constituting a comonomer and consequently modifying the properties, particularly the mechanical ones, of the poly(HEMA/EMA) copolymer.
In any case, the person skilled in the art is not unaware that the increase in the rate of intervening cross-linking agent reduces the water content of the hydrogels and increases their vitreous transition temperature.
It is indicated here that said cross-linking agent intervenes in the structure of the copolymer, generally in such a quantity that the ratio:       R    xe2x80x2    =                                          total  number  of  reactive  functions  of  said                                                             cross-linking  agent  present                                                                        total  number  of  reactive  functions  (methacrylates)  of  the                                                            reagents  present  (HEMA,  EMA)
is included between 6.10xe2x88x923 and 60.10xe2x88x923. Said ratio Rxe2x80x2 is advantageously 10xe2x88x922.
Concerning the reactive functions of said cross-linking agent, it is advantageously question of acrylate and/or methacrylate functions. The person skilled in the art knows numerous cross-linking agents performing such functions, and in particular:
butanediol dimethacrylate and diacrylate
hexanediol dimethacrylate and diacrylate
decanediol dimethacrylate and diacrylate
ethylene glycol dimethacrylate (EDMA)
tetraethylene glycol dimethacrylate.
Within the scope of the present invention, the intervention of the cross-linking agents listed hereinabove and more particularly that of EDMA, is recommended in non-limiting manner.
Thus, the poly(HEMA/EMA) copolymer constituting the particles of the dispersed phase of the diphasic compositions of the invention is cross-linked by cross-linking agents of this type (or of an equivalent type) of which trace is obviously found in its skeleton.
Said poly(HEMA/EMA) copolymer is prepared in manner known per se, by copolymerizing a mixture of HEMA and EMA monomers in the presence of efficient quantities of at least one polymerization initiator and at least one cross-linking agent.
It has been seen hereinabove that, concerning the cross-linking agent, an efficient quantity (generally from 0.5 to 5 parts by weight and advantageously from 0.5 to 2 parts by weight, for 100 parts by weight of monomers: HEMA+EMA), of a cross-linking agent such as EDMA, intervenes. Said EDMA may intervene in particular at the rate of 0.8 part by weight. Other cross-linking agents as indicated hereinabove, may intervene in place of said EDMA.
By way of initiator of the radical HEMA-EMA copolymerization, the following may in particular be used:
a mixture of sodium phosphite and sodium phosphate (or any other oxidoreduction couple);
an azo compound such as azobisisobutyronitrile (AIBN) or (2,2xe2x80x2-azobis (2,4-dimethyl valeronitrile)(AIVN), in particular marketed by WAKO under reference V65, of which the developed formulae are reproduced hereinbelow:
This latter compound is particularly preferred in view of its low toxicity, as well as that of its products of degradation. (However, it will be generally noted that said polymerization initiator intervenes in a very small quantity and is generally eliminated at the end of the method for preparing the hydrogel);
a peroxide such as benzoyl peroxide.
The person skilled in the art knows how to master the quantity of intervention of said radical polymerization initiator (generally less than 1 part by weight for 100 parts by weight of monomers: HEMA+EMA) and, in general. the kinetics of polymerization of the reactional mixture. In particular, he knows that, as oxygen neutralizes the action of said polymerization initiator, it is highly preferable to eliminate it from the reactional mixture before the rise in temperature. A bubbling-through of inert gas of said reactional mixture is highly recommended. Concerning the heating programme, its optimalization is within the scope of the person skilled in the art.
Said cross-linked poly(HEMA+EMA) copolymer is therefore largely recommended by way of material constituting the particles of the dispersed phase of the diphasic compositions of the invention.
The precisions given hereinabove with reference to the preparation of said copolymer, particularly those relative to the nature of the cross-linking agent(s) and polymerization initiator(s) likely to intervene, are obviously applicable to the context of the (co)polymerization and cross-linking of monomers of other natures for the preparation of other polymers or copolymers suitable for constituting the particles of the dispersed phase.
Within the diphasic compositions of the invention. the particles of the dispersed phase generally intervene at a rate of 10 to 30% by mass, advantageously at a rate of 15 to 25% by mass. Generally, one has:       10              xe2x80x83            %          xe2x80x83    ≤            mass                    xe2x80x83                  of                    xe2x80x83                  the                    xe2x80x83                  dispersed                              xe2x80x83                                  xe2x80x83                          phase                                                          mass                                            xe2x80x83                                          of                                            xe2x80x83                                          the                                            xe2x80x83                                          dispersed                                            xe2x80x83                                          phase                        +                                                            mass                                      xe2x80x83                                    of                                      xe2x80x83                                    the                                      xe2x80x83                                    continuous                                      xe2x80x83                                    phase                                ≤      30              xe2x80x83                  %      .
The continuous phase is considered hydrated, while the dispersed phase may be considered dry or at equilibrium. Advantageously, in this type of ratio, the dry mass of the dispersed phase, i.e. the dry mass of the particles, is considered.
It is specified here that a single type of particles generally intervenes within the dispersed phase. However, it is in no way excluded from the scope of the invention to employ particles of different shape and/or nature . . . , conjointly.
Concerning the preparation of the diphasic compositions of the invention, the person skilled in the art has already understood that it does not raise particular difficulties. Said preparation, which constitutes the second object of the present invention, comprises:
the preparation of the continuous phase (advantageously that of a hydrogel of cross-linked hyaluronic acid);
the preparation of the dispersed phase (particles of at least one hydrogel of a (co)polymer obtained by polymerizing and cross-linking acrylic acid and/or methacrylic acid and/or at least one derivative of said acids);
the incorporation and the mixture in said continuous phase of said dispersed phase.
The preparation of the continuous phase and in particular that of a hydrogel of cross-linked hyaluronic acid, advantageously at the rate of cross-linking and at the concentration of acid specified hereinabove, does not raise any particular difficulty.
Similarly, the particles of the dispersed phase may be obtained by any method known per se. Particles with symmetry of revolution, with smooth surface, and in particular microspheres, may be obtained by emulsification.
It has been seen that it was recommended to prepare fragments with rough surface; said fragments being advantageously obtained by mechanically crushing an appropriate mass of hydrogel.
Within the framework of the method of the invention, it is advantageously recommended to prepare the particles of the dispersed phase, to dry them and to add them, dried, to the continuous phase.
The prepared diphasic composition is advantageously sterilized for storage. It is recommended to pack it, before sterilization and storage. It is advantageously packed in syringes. It is in that case ready for use.
In accordance with its final object, the invention therefore relates to a filling material, useful in reparative surgery and in plastic surgery, based on the diphasic compositions such as described hereinabove.
Said material is particularly high-performance, in particular in terms of stability and non-traumatizing nature, due to the nature and consistency of its continuous phase (advantageously cross-linked HA) and dispersed phase (hydrogel).
The use of such a filling material is recommended for filling in particular wrinkles of the face such as the glabellar wrinkle, the peri-buccal wrinkles, the naso-genial furrows, for attenuating crowsfeet . . .

Diphasic injection composition containing dispersed and continuous phases useful for reparative and plastic surgery