A method for improving the integrity of the corneal epithelium by introducing into the eye an effective amount of a ophthalmically compatible retinoid sufficient to enhance the integrity of the corneal epithelium.

This invention relates to the prevention of damage to the cornea in mammals resulting from discontinuities in the epithelial layer.
Ophthalmic lenses have been investigated for a number of years. Such materials can generally be subdivided into two major classes, namely hydrogels and non-hydrogels. Non-hydrogels do not absorb appreciable amounts of water, whereas hydrogels can absorb and retain water in an equilibrium state.
Those skilled in the art have long recognized that the surface characteristics of contact lenses play a major role in their ocular compatibility. For example, it is known that increasing the hydrophilicity of the contact lens surface improves the wettability of the contact lenses. This in turn is associated with improved wear comfort of contact lenses. Additionally, the surface of the lens can affect the lens""s susceptibility to deposition, particularly the deposition of proteins and lipids from the tear fluid during lens wear. Accumulated deposits can cause eye discomfort or even inflammation. In the case of extended wear lenses (i.e. lenses used without daily removal of the lens before sleep), the surface is especially important, since extended wear lenses must be designed for high standards of comfort and biocompatibility over an extended period of time.
The degree of ocular compatibility is more specifically the compatibility of the superior corneal epithelium with the posterior surface of the contact lens. Because the radius of curvature of the posterior surface of the contact lens is usually slightly smaller than radius of curvature of the convex anterior surface of the cornmeal epithelium, the thinnest portion of the tear film separating the corneal epithelium and the contact lens is usually at the outer perimeter of the contact lens.
One can envision this area by striking an imaginary circle on the cornea that is concentric with the pupil and that has a radius equal to that of the contact lens. Allowing for the normal movement of the contact lens on the cornea, one would broaden the width of the imaginary circle. This circle or its arcuate portions are then of principal interest in the present invention.
Since the introduction of soft daily wear contact lenses in the late 1960""s and extended wear soft contact lenses in the 1980""s, the number of people wearing contact lenses for vision correction has increased dramatically. It is estimated that the number of contact lenses wears in the United States alone is in excess of 25 million1. Contact lenses are prescribed by optometrists and ophthalmologists, and most contact lens wearers follow their health care provider""s instructions on the use and care of the contact lenses. Thus the vast majority of contact lens wearers enjoy the benefits of their contact lenses with no adverse side effects.
Although the relative numbers of problems arising from contact lens wear are quite small, the absolute number of incidents has risen with the increasing number of contact lens wearers. Thus the increasing popularity of contact lenses has yielded a concomitant increase in the incidence of complications related to contact lens wear. Corneal infiltrates and superior epithelial arcuate lesions (SEALs) are of particular interest since neither are completely described with respect to either causative factors or predisposing conditions. The SEALs appear principally in arcuate sections of the circular region defined by the outer posterior edge of the contact lens as discussed above.
Corneal infiltrates account for a small percentage of all contact lens-related problems and are more commonly found in extended wear versus daily wear patients. Corneal infiltrates arise in the cornmeal epithelium and are characterized by an inflammatory response, such that there is a visible (1 to 2 mm) accumulation of polymorphonucleocytes (PMNs) to the localized area. Infiltrates have been observed to be sterile and non-sterile, symptomatic and asymptomatic. Corneal infiltrates are most commonly found on the superior cornea, although are also found elsewhere. Most patients present with a single infiltrate, however multiple infiltrates are not uncommon. Generally, there is minimal disruption to the overlying epithelium and epithelial edema or superficial punctate keratitis is found in approximately half of the cases. Anterior chamber inflammation is absent or minimal in affected patients. A number of causative agents have been proposed, ranging from hypersensitivity/toxicity to contact lens care product preservatives2, to bacteria3/blepharitis4, to protein lens deposits5. However, given the range and degree of symptoms it seems most probable that these infiltrates are more likely the result of a general immunological response, since PMNs are relatively non-specific components of the immune system, which respond to a variety of chemotactic and other signals.
Superior epithelial arcuate lesions are primarily the result of mechanical damage of the corneal epithelium, typically due to contact lens wear. Characteristic arcuate epithelial staining is observed where micro-abrasions readily take up fluorescein at the site of the arc of contact between the edge of the lens and the cornea.
The similarity between these two conditions, aside from contact lens wear, is the involvement or proximity to the corneal epithelium. Thus it would be desirable to provide a method of preventing these conditions or mitigating their severity.
The invention provides a method for improving the integrity of the corneal epithelium in an eye wearing a contact lens comprising introducing an ophthalmically compatible form of a retinoid into the eye in an amount sufficient to enhance the integrity of the corneal epithelium. The method of the invention may optionally include examining for the presence of retinoid deficiency (clinical and sub-clinical). Suitable methods for determining the level of available retinoic acids include measuring the level of retinoic acids in the serum or tear film.
In accordance with the invention, it has been found that certain individuals in the contact lens wearing population may be predisposed to developing superior epithelial arcuate lesions and/or corneal infiltrates. While not to limit the scope of the invention by a recitation of theory, it is believed that insufficient levels of retinoid (alone or in combination with other factors) or other nutritional deficiencies may increase the surface roughness of the epithelium. This increased surface roughness can be accompanied by local retinoid deficiencies. When the roughness of the epithelium increases, it may minimally cause the epithelium to become xe2x80x9cleakyxe2x80x9d or functionally ineffective at completely protecting the underlying layers of the corneal epithelium. As a result of the lack of cellular differentiation, the epithelium is more susceptible to invasion by microorganisms and/or to chemotactic substances, which can recruit the leukocytes observed in non-sterile and sterile infiltrates alike. Exposure of the underlying epithelial layers to chemotactic substances and microbial invaders/metabolites will cause the accumulation of PMNs or other leukocytes characteristic of the corneal infiltrate phenomenon.
In addition (again, not to limit the invention by a recitation of theory) it is believed that insufficient levels of retinoid (alone or in combination with other factors) or other nutritional deficiencies which can result in local retinoid deficiencies, minimally cause the epithelium to be more susceptible or prone to SEALs. It has been found that the epithelium appears to be less resistant to mechanical abrasion due to the reduction of cellular differentiation as a direct result of retinoid deficiency.
Retinoids are known to have a profound influence on many aspects of ocular health. Vitamin A deficiency is well documented as a cause of childhood blindness, xerophthalmia, throughout the world. Sub-clinical vitamin A deficiency, without overt symptoms, has been observed in populations throughout the world6,7,8,9. Additionally, Vitamin A deficiency, clinical and sub-clinical is positively correlated with smoking. Vitamin A is known to regulate the proliferation and differentiation of corneal epithelial cells and to preserve the integrity of the conjunctiva, and thus has a significant impact on overall ocular health.
The effects of overt retinoid deficiency are obvious, with xerophthalmia being the most prominent outcome of severe deficiency causing half a million or more cases of pediatric blindness worldwide. However sub-clinical retinoid deficiencies, protein deficiencies (leading to decreased levels of retinol binding protein) and the long term effects of reversed early childhood and infant deficiencies are not well understood or characterized. Sub-clinical retinoid deficiencies are known to increase the severity of infectious morbidity, exacerbate iron deficient anemia, retard growth and are responsible for one to three million childhood deaths each year10.
Vitamin A deficiency has also been shown to increase inflammatory responses. Vitamin A deficient rats exhibited 43% increased in the number of circulating leukocytes, had a four time higher T-cell proliferative response and a two times higher interferon-gamma production in vitro as compared to control animals. Granulocyte dependent inflammation was increased, the spontaneous release of nitric oxide form the peritoneal phagocytes was five time higher and the number of peritoneal mast cell was 1.5 times higher in vitamin A deficient animals in contrast to control animals11. Dawson, et al. evaluated the effect of marginal vitamin A status on the number and function of natural killer cells in aging Lewis rats. They determined that the cells lytic activity declined with increasing age and decreasing vitamin A supplementation, suggesting that in humans elderly people consuming diets chronically low in vitamin A may be at increased risk for infectious or neoplastic diseases12.
Vitamin A is known to have a positive effect on epithelial integrity and cellular differentiation. Alterations in the epithelial lining of vital organs occur early in deficiency, suggesting an important role for the barrier function. Conjunctival-impression cytology testing can detect the presence of larger irregular keratinized cells and the absence of mucous-secreting goblet cells in vitamin A deficient individuals13. Increases in epithelial cellular stratification and keratinization can lead to decreases in barrier efficacy and subsequent increases in chemotactic substance and microorganism penetration into the epithelium. This is postulated to lead directly to an increase in corneal infiltrate occurrence, accounting for both sterile and non-sterile infiltrates, in affected individuals, as well as the appearance of SEALs due to vulnerable epithelium. Low plasma retinol levels have been shown to be correlated with low retinol binding protein plasma levels (r=0.77) indicating that, while vitamin A deficiency exists in malnourished populations, low retinol levels may be partly related to decreased levels of its carrier protein14,15. Additionally, decreased cellular differentiation and lower goblet cell densities directly impact the amount of mucin-like glycoprotein16 and mucin produced17. Aside from contributing to both the reheology and stability of tear film, mucins also function as a physical barrier and bind microorganisms and immune cells specifically and non-specifically. Therefore, decreases in the production of these substances should also be related to an increase in corneal infiltrate occurrence in vitamin A deficient (or protein deficient) contact lens wearing individuals. Local or systemic vitamin A deficiency (resulting from diet or tobacco use) and protein malnutrition may have a significant influence on the occurrence of both corneal infiltrates and SEALs.
In accordance with the present invention, the retinoid may be administered topically or systemically. If the retinoid is administered locally, it is preferred to administer the retinoid in an ophthalmically compatible solution in the form of a drop.
The retinoid of the invention may be administered dropwise in an ophthalmic solution, or as a mist, gel or ointment. The method of the invention is useful for improving the long-term ophthalmic compatibility of extended wear contact lenses. In a preferred embodiment, the extended-wear contact lenses are silicone hydrogel lenses and the solution is administered dropwise or in the form of a contact lens conditioning solution.
Gels and ointments are particularly preferred for patients wearing rigid gas permeable (RGP) contact lenses, especially continuous-wear RGP lenses and orthokeratology lenses. When used in conjunction with orthokeratology lenses, the retinoid is administered as a gel or ointment to the eye before inserting the orthokeratology lens before sleep at night.
The retinoid may be administered as a coating on a contact lens. For example, the retinoid may be added to a lens care product such as a multipurpose cleaning and disinfecting solution. One example of multipurpose lens care solution is ReNu MultiPlus(trademark) solution produced by Bausch and Lomb, Incorporated of Rochester, N.Y.
The retinoid may also be applied to the contact lens during the contact lens manufacturing process. The contact lens surface may be treated with a retinoid by any suitable means, for example: spreading, dipping or spraying. The mechanism by which the retinoid attaches to the surface of the contact lens is not critical for this invention provided that the retinoid can detach or desorb from the contact lens surface into the epithelium. One example of a useful attachment mechanism to achieve sustained release is covalent bonding between a contact lens surface and a retinol group. Alternatively, the retinoid may be attached to a polymer having both hydrophobic and/or hydrophilic sites. For example, the hydroxyl group of vitamin A palmitate can be attached to a dimethacrylate/glycidyl methacrylate (DMA/GMA) copolymer, which may then be attached to the surface of a contact lens through residual glycidyl groups. In a preferred embodiment, the retinoid is applied to the contact lens in a sustained release form, where, for example, a covalently bound retinoid is hydrolyzed from the lens thus liberating the free retinoid. Alternatively, hydrophobic interactions can be used to bind a hydrophobic retinod, such as vitamin A plamitate, to hydrophobic contact lens material. The vitamin A plamitate would be released from the contact lens in a controlled, sustained manner.
The retinoid may also be administered systemically, i.e., orally or by injection, to provide a normal level of retinoid in the serum. While normal levels of retinoids in the serum are physiologically beneficial, it has been found that such levels do not necessarily take the place of the method of the invention for treating SEALs and corneal infiltrates. For example, protein deficiency has been found to inhibit delivery of systemically administered retinoids to the epithelium. Thus it has surprisingly been found that the method of the invention is effective for treating and/or preventing recurrence of SEALs and corneal infiltrates even when serum retinoid levels would predict that no additional retinoid is needed.
The retinoid is administered in a vehicle within a range of suitable concentrations. At a minimum, the concentration of retinoid is sufficient to improve the integrity of the corneal epithelium. For an ophthalmic solution applied dropwise two to eight times per day, a suitable range of concentrations is from about 200 to about 5000 IU/ml, with the maximum concentration and dosage consistent with ocular comfort. One suitable treatment regimen for an ophthalmic solution containing vitamin A palmitate at a concentration of 1000 IU/ml is one or two drops per eye administered four times per day.
The contact lenses useful in the present invention may comprise rigid materials as well as soft (hydrogel) materials. Hydrogels comprise hydrated, crosslinked polymeric systems containing water in an equilibrium state. Conventional hydrogel lens materials include polymers containing monomers such as 2-hydroxyethyl methacrylate (HEMA), glyceryl methacrylate, N-vinylpyrrolidone (NVP) and N,N-dimethacrylamide.
Flexible ophthalmic lens materials useful in the present invention include silicone hydrogels as well as conventional hydrogels and low-water elastomeric materials. Examples of flexible ophthalmic lens materials useful in the present invention are taught in U.S. Pat. Nos. 5,908,906 to Kxc3xcnzler et al.; 5,714,557 to Kxc3xcnzler et al.; 5,710,302 to Kxc3xcnzler et al.; 5,708,094 to Lai et al.; 5,616,757 to Bambury et al.; 5,610,252 to Bambury et al.; 5,512,205 to Lai; 5,449,729 to Lai; 5,387,662 to Kxc3xcnzler et al. and 5,310,779 to Lai; which patents are incorporated by reference as if set forth at length herein.
U.S. Pat. Nos. 6,037,328, 6,008,317, 5,981,675, 5,981,669, 5,969,076, 5,945,465, 5,914,355, 5,858,937, 5,824,719 and 5,726,733 teach ophthalmic lens materials containing HEMA monomers.
U.S. Pat. Nos. 6,071,439, 5,824,719, 5,726,733, 5,708,094, 5,610,204, 5,298,533, 5,270,418, 5,236,969 and 5,006,622 teach ophthalmic lens materials containing glyceryl methacrylate monomers.
U.S. Pat. Nos. 6,008,317, 5,969,076, 5,908,906, 5,824,719, 5,726,733, 5,714,557, 5,710,302, 5,708,094, 5,648,515 and 5,639,908 teach ophthalmic lens materials containing NVP monomers.
U.S. Pat. Nos. 5,539,016, 5,512,205, 5,449,729, 5,387,662, 5,321,108 and 5,310,779 teach ophthalmic lens materials containing dimethacrylamide monomers.
The preferred conventional hydrogel materials typically contain HEMA, NVP and TBE (4-t-butyl-2-hydroxycyclohexyl methacrylate). Polymacom(trademark) materials, for example the Soflens 66(trademark) brand contact lenses (commercially available from Bausch and Lomb Incorporated of Rochester, N.Y.) are examples of particularly preferred conventional hydrogel materials.
Silicone hydrogels generally have a water content greater than about five weight percent and more commonly between about ten to about eighty weight percent. Materials are usually prepared by polymerizing a mixture containing at least one silicone-containing monomer and at least one hydrophilic monomer. Either the silicone-containing monomer or the hydrophilic monomer may function as a crosslinking agent (a crosslinker being defined as a monomer having multiple polymerizable functionalities) or a separate crosslinker may be employed. Applicable silicone-containing monomeric units for use in the formation of silicone hydrogels are well known in the art and numerous examples are provided in U.S. Pat. Nos. 4,136,250; 4,153,641; 4,740,533; 5,034,461; 5,070,215; 5,260,000; 5,310,779; and 5,358,995.
A preferred silicone hydrogel material comprises (in the bulk monomer mixture that is copolymerized) 5 to 50 percent, preferably 10 to 25, by weight of one or more silicone macromonomers, 5 to 75 percent, preferably 30 to 60 percent, by weight of one or more polysiloxanylalkyl (meth)acrylic monomers, and 10 to 50 percent, preferably 20 to 40 percent, by weight of a hydrophilic monomer. In general, the silicone macromonomer is a poly(organosiloxane) capped with an unsaturated group at two or more ends of the molecule. In addition to the end groups in the above structural formulas, U.S. Pat. No. 4,153,641 to Deichert et al. discloses additional unsaturated groups, including acryloxy or methacryloxy. Fumarate-containing materials such as those taught in U.S. Pat. Nos. 5,512,205, 5,449,729, and 5,310,779 to Lai are also useful substrates in accordance with the invention. Preferably, the siliconene macromonomer is a silicon-containing vinyl carbonate or vinyl carbamate or a polyurethane-polysiloxane having one or more hard-soft-hard blocks and end-capped with a hydrophilic monomer.
The suitable monomers that form hydrogels useful in the present invention include, for example, acids such as acrylic and methacrylic acid, amides such as N,N-dimethyl acrylamide, N,N-dimethyl methacrylamide, cyclic lactams such as N-vinyl-2-pyrrolidone and poly(alkene glycol)s functionalized with polymerizable groups. Examples of useful functionalized poly(alkene glycol)s include poly(diethylene glycol)s of varying chain length containing monomethacrylate or dimethacrylate end caps. In a preferred embodiment, the poly(alkene glycol) polymer contains at least two alkene glycol monomeric units. Still further examples are the hydrophilic vinyl carbonate or vinyl carbamate monomers disclosed in U.S. Pat. Nos. 5,070,215, and the hydrophilic oxazolone monomers disclosed in U.S. Pat. No. 4,910,277. Other suitable hydrophilic monomers will be apparent to one skilled in the art. In a particularly preferred embodiment, the hydrophilic monomers used in the contact lens material are capable of forming a stable complex with a cationic polysaccharide.
Rigid ophthalmic lens materials include rigid-gas-permeable (xe2x80x9cRGPxe2x80x9d) materials. RGP materials typically comprise a hydrophobic crosslinked polymer system containing less than 5 wt. % water. RGP materials useful in accordance with the present invention include those materials taught in U.S. Pat. Nos. 4,826,936 to Ellis; 4,463,149 to Ellis; 4,604,479 to Ellis; 4,686,267 to Ellis et al.; 4,826,936 to Ellis; 4,996,275 to Ellis et al.; 5,032,658 to Baron et al.; 5,070,215 to Bambury et al.; 5,177,165 to Valint et al.; 5,177,168 to Baron et al.; 5,219,965 to Valint et al.; 5,336,797 to McGee and Valint; 5,358,995 to Lai et al.; 5,364,918 to Valint et al.; 5,610,252 to Bambury et al.; 5,708,094 to Lai et al.; and 5,981,669 to Valint et al. U.S. Pat. No. 5,346,976 to Ellis et al. teaches a preferred method of making an RGP material. The patents mentioned above are incorporated by reference as if set forth at length herein.

Method for enhancing integrity of epithelium using retinoic acid


An apparatus for removing tissue and/or other material from a patient, particularly a breast of a patient, is provided. The apparatus generally includes a handpiece and a tissue removal mechanism connected thereto. The tissue removal mechanism includes a cannula having an open distal tip and an outer diameter of less than about 5 mm, or less than about 2 mm. The mechanism further includes a rotatable element having a distal portion with helical threading. The distal portion of the rotatable element extends beyond the open distal tip of the cannula in order to allow tissue to prolapse between turns of the helical threading. The apparatus is designed to draw soft tissue into the cannula upon rotation of the rotatable element and without the need for supplemental sources of aspiration.

The present invention relates generally to medical devices, and, more particularly, to micro-invasive devices and methods for removing breast tissue for biopsy and treatment.
The medical industry is constantly evolving through the adaptation of improved pharmaceutical, biotechnology, and medical device products and procedures. Techniques and technologies are being developed to treat internal areas of the body through less invasive means.
It is often desirable and frequently necessary to remove a portion of tissue from humans and other animals, particularly in the diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions and other diseases or disorders. Typically, in the case of cancer, when the physician establishes by means of procedures such as palpation, x-ray or ultrasound imaging that suspicious circumstances exist, a biopsy is performed to determine whether the cells are cancerous. Biopsy may be done by an open or percutaneous technique. Open biopsy removes the entire mass (excisional biopsy) or a part of the mass (incisional biopsy). Percutaneous biopsy, on the other hand, is usually done with a needle-like instrument and may be either a fine needle aspiration (FNA) or a core biopsy. In FNA biopsy, individual cells or clusters of cells are obtained for cytologic examination and may be prepared such as in a Papanicolaou smear. In core biopsy, as the term suggests, a core or fragment of tissue is obtained for histologic examination which may be done via a frozen section or paraffin section. The type of biopsy utilized depends in large part on circumstances present with respect to the patient and no single procedure is ideal for all cases. However, core biopsy is extremely useful in a number of conditions and continues to be used frequently by the medical profession.
To arrive at a definitive tissue diagnosis, intact tissue is needed from an organ or lesion within the body. In most instances, only part of the organ or lesion need be sampled. However, the portions of tissue obtained must be representative of the organ or lesion as a whole. In the past, to obtain tissue from organs or lesions within the body, surgery had to be performed to locate, identify and remove the tissue. With the advent of medical imaging equipment (x-rays and fluoroscopy, computed tomography, ultrasound, nuclear medicine, and magnetic resonance imaging) it has become possible to identify small abnormalities even deep within the body. However, definitive tissue characterization still requires obtaining adequate tissue samples to characterize the histology of the organ or lesion. For example, mammography can identify non-palpable (not perceptible by touch) breast abnormalities earlier than they can be diagnosed by physical examination. Most non-palpable breast abnormalities are benign; some of them are malignant. When breast cancer is diagnosed before it becomes palpable, breast cancer mortality can be reduced. However, it is often difficult to determine if pre-palpable breast abnormalities are malignant, as some benign lesions have mammographic features which mimic malignant lesions and some malignant lesions have mammographic features which mimic benign lesions. Thus, mammography has its limitations. To reach a definitive diagnosis, tissue from within the breast must be removed and examined under a microscope. Early biopsy techniques for reaching a definitive tissue diagnosis for non-palpable breast disease required a mammographically guided localization, either with a wire device, visible dye, or carbon particles, followed by an open, surgical biopsy utilizing one of these guidance methods to lead the surgeon to the non-palpable lesion within the breast.
Open surgical breast biopsies have many drawbacks. They can be disfiguring, expensive and are imperfect. Open surgical biopsies also carry a small mortality risk (due to the risks of anesthesia) and a moderate morbidity rate (including bleeding, infection, and fracture or migration of the localizing wire). In cases where multiple lesions are present in the breast, a surgeon is reluctant to biopsy each lesion due to the large tissue mass that must be extracted with each lesion. The most convenient lesion may be taken which most often results in an incomplete diagnosis.
Percutaneous breast biopsy techniques are more desirable in many instances, particularly in light of modern imaging techniques which are able to pinpoint non-palpable tissue masses in the breast and consequently, the increased frequency of biopsies that are necessary for diagnosis of these tissue masses. A well known instrument used quite extensively for core biopsies in the past is manufactured by Travenol Laboratories of Deerfield, Ill., and is sold under the mark xe2x80x9cTRU-CUT.xe2x80x9d This manual biopsy instrument at one time enjoyed as much as 98% of the market for such devices. As disclosed in U.S. Pat. No. 3,477,423, the instrument comprises a two-piece assembly: an outer cutting cannula mounted to one hub member and an inner stylet with a sampling notch ground into it mounted to a second hub, with the hubs being slidably interlocked. The instrument is assembled and placed into the body with the outer cutting cannula just to the rear of a lancet point or beveled distal end of the stylet. Upon inserting the device up to or in front of the area to be biopsied, advancement of the assembly is halted. The stylet is manually advanced distally of the cannula with the cannula held stationery. Upon advancement of the stylet, the specimen notch is exposed. Tissue surrounding the stylet prolapses into the specimen notch and the cutting cannula is then manually advanced distally over the stylet, slowly shearing off the tissue entrapped in the stylet""s specimen notch. The instrument is then either (a) withdrawn and the stylet advanced distally to expose the tissue for preparation for study or (b) left in place and only the stylet is proximally removed from within the cannula so a determination of successful sampling may be made. If the sampling was not successful, the stylet may be reinserted into the cannula, which remains positioned within the patient, and an attempt to reposition the assembly of stylet and cannula and repeat sampling can be made.
Such a technique using this basic design of a biopsy instrument is referred to as a manual technique. One drawback to the manual technique is that it requires a great deal of manual dexterity and motor coordination, along with the use of both hands, to advance the stylet while maintaining the position of the cannula and then to maintain the position of the stylet while advancing the cannula. Another drawback is that the cannula is advanced relatively slowly, resulting in an extremely poor cutting action and allowing the surrounding tissue an opportunity to collapse, thus making no use of the stored kinetic energy in the material being severed. Further disadvantages are encountered when the tissue volume to be sampled contains areas of higher density than that of surrounding tissue, such as areas of calcification commonly associated with certain types of cancerous growths. A manually inserted sampling device is often incapable of penetrating the denser area of tissue which merely deflects the course of the cannula/stylet structure around the dense area and into the more compliant surrounding tissue. In the late 1980""s, two different stereotactic guidance systems were modified to allow the guiding portion of each system to accommodate spring powered devices such as the Biopty(copyright) (Bard Radiology) gun. As used herein, the term xe2x80x9cgunxe2x80x9d is used to refer to a tissue sampling device designed for xe2x80x9cone-handedxe2x80x9d operation. A feature common to many of these devices is the shape of the device being adapted to fit the hand of a medical practitioner with a pistol-like grip, complete with a triggering mechanism. Free-hand ultrasound guidance techniques were also developed to guide the Biopty(copyright) gun to breast lesions detected by ultrasound.
With image-guided percutaneous core breast biopsy, it should be possible to greatly reduce the number of open, surgical breast biopsies performed. However, there are limiting factors with image-guided breast biopsies. Conventional, manually operated two-step devices are awkward to manipulate, and the tissue samples obtained thereby are often unsatisfactory.
A variety of automatic and semiautomatic biopsy instruments have been developed which are spring loaded gun-type devices. A biopsy gun currently used is described in U.S. Pat. No. Re. 34,056, entitled xe2x80x9cTISSUE SAMPLING DEVICE,xe2x80x9d issued to Lindgren et al. Additional examples of biopsy gun devices are disclosed in U.S. Pat. Nos. 4,600,014 and 4,958,625.
Such devices use a design comprising a handle held in a physician""s palm, and a guide tube extending forwardly of the handle. A cannula is slidably disposed within the guide tube and is movable from within the guide tube forwardly out of the distal end of the guide tube. A sampling stylet is telescopically disposed within the cannula and projects from the rear of the handle. In an automatic mode of operation, the cannula, when in the retracted position, is spring loaded by means of a compressed spring. A release lever, which works against the compressed spring, is activated to release compression of the spring which then expands and pushes the cannula outwardly over the stylet. This instrument, as stated, requires two handed operation. Also, since the stylet is not removable proximally from within the handle, the entire instrument must be withdrawn to obtain access to the sample.
A fully automatic instrument manufactured by Radiplast, Inc. of Sweden is described in U.S. Pat. No. 4,699,154. This instrument comprises a reusable, spring-loaded box-shaped housing or handpiece, which activates a disposable cannula and stylet set. Both the stylet and cannula are activated in rapid succession. The instrument has the advantage of reducing the dexterity and motor coordination necessary in the use of manual devices and also eliminates the slow cutting action of the manually advanced cannula, replacing it with a very quick, clean cut. This instrument, however, also has its drawbacks. First, the reusable handpiece is very large, heavy, cumbersome, and expensive. They are also typically spring-powered devices and must be manually cocked with some sort of plunger bar. Such xe2x80x9ccockingxe2x80x9d of the gun requires considerable force and the gun must be cocked for each biopsy cut. When actuated, the springs provided in the gun accelerate the needles until a mechanical stop position is reached which can create a loud snapping noise and jerking motion which is a problem both to the physician and the patient. A further drawback is encountered in automatically activating both the stylet and the cannula, as opposed to activating the stylet manually, in that the rapid speed at which the cannula follows the stylet into the tissue does not allow much tissue to collapse into the specimen notch, limiting the size of the sample.
U.S. Pat. No. 5,183,054, entitled xe2x80x9cACTUATED BIOPSY CUTTING NEEDLE WITH REMOVABLE STYLET,xe2x80x9d issued to Burkholder et al., discloses a biopsy device having a tubular cannula through which a stylet, having a stylet cavity near the distal end, is placed. The stylet is removable from the cannula and removed from the biopsy device through the housing so that the tissue sample obtained by the biopsy device may be manually retrieved while the cannula remains in place within the patient, near the area being sampled. Thereafter, the stylet may be reinserted through the housing and cannula into the patient""s tissue where additional tissue samples may be obtained. In this way, trauma to the tissue that ordinarily occurs upon reinsertion of the cannula and stylet is minimized.
U.S. Pat. No. 5,234,000, entitled xe2x80x9cAUTOMATIC BIOPSY DEVICE HOUSING A PLURALITY OF STYLETS,xe2x80x9d issued to Hakky et al. describes a biopsy device for taking a plurality of samples of tissue from a living being. The device comprises a housing having a portion arranged to be held by a person using the device, a cannula having a proximal portion and a distal portion and being coupled to the housing. A plurality of stylets are located in the housing, with each of the stylets having a proximal end, a distal end, and a tissue receiving notch located adjacent the distal end. Each stylet is individually propelled through the cannula into the body so that a portion of the tissue prolapses into the notch.
There currently exists a need for a more effective microsurgical device for obtaining a sample of breast tissue from a patient.
New apparatus and methods for removing breast tissue and/or other material from a human breast have been discovered. The present invention provides apparatus, for example, micro-invasive apparatus, to remove tissue or other material from a target area of a breast to provide one or more benefits, such as diagnostic benefits, therapeutic benefits and the like.
The apparatus of the invention are useful for removing unwanted, diseased, or even healthy bodily materials, for example, tissues, for medical treatment and/or therapeutic purposes. Advantageously, the present invention is suitable for use in many surgical settings and is suitable for performing various material removal procedures using methodologies, for example, in terms of methods of introducing the apparatus into the body and removing the apparatus from the body, which are substantially analogous to conventional surgical techniques. Necessary or desirable adaptations of the apparatus of the present invention for specific medical treatment, e.g., diagnostic, and therapeutic purposes will be readily appreciated by those of skill in the art.
Accordingly, apparatus for removing tissue from a target area of a breast are provided. In one broad aspect, the apparatus comprise a handpiece and a tissue removal element connected or coupled thereto. The tissue removal element includes a cannula, for example, a substantially rigid or flexible cannula, and a rotational element disposed in the cannula. The rotational element is connected to a source of rotational energy, for example, a motor. The rotational element is disposed at least partially in the cannula. The cannula includes an open distal tip structured to be placed in a breast, and preferably a proximal end connected, for example, removably connected, to the handpiece. The tissue removal element is structured and effective to draw breast tissue or other material from the target area or site, for example, into the open distal tip, in response to, for example, as a result of, rotation of the rotational element relative to the cannula.
In one embodiment, the rotational element is structured to at least assist in drawing material from a breast into the cannula. For example, the rotational element and the cannula cooperatively engage to form or create a source of suction sufficient to draw the tissue or other material into the cannula in response to rotation of the rotational element relative to the cannula. Advantageously, the cannula, in particular the interior hollow space formed or defined by the cannula, and the rotational element are sized and positioned, relative to each other, to create a source of suction or pumping action in response to the rotational element rotating relative to the cannula. Without wishing to limit the invention to any particular theory of operation, it is believed that this functioning of the cannula/rotational element combination is at least somewhat analogous to the functioning of a pump, for example, a pump based on the principles of the xe2x80x9cArchimedes"" screwxe2x80x9d, causing the material to be drawn or pulled or pumped into the open distal tip of the cannula and through the cannula in being removed from the target area of the human/animal body.
Preferably, the suction/pumping action created or formed by the cannula/rotational element combination is itself sufficient and effective so that no other, for example, no additional or supplemental, source of suction or pumping action is employed, needed or required to effectively remove material from the target area in accordance with the present invention.
In one embodiment of the invention, the rotational element includes a shaft and one or more outwardly extending projections, for example threads, preferably having a substantially helical configuration. Advantageously, the rotational element includes a distal portion with such projections or threads. The proximal portion of the rotational element may or may not include such projections or threads. In a very useful embodiment, the proximal portion is substantially free of such projections or threads.
The distal portion of the rotational element, in a useful embodiment, extends beyond the open distal tip or inlet of the cannula, for example, by a distance in a range of about 0.02 inches to about 1 inch beyond the open distal tip of the cannula. For example, the distal portion may extend a distance equal to at least about one-half of the spacing between adjacent projections or threads. The rotational element distal portion may extend a distance equal to more than about one spacing, for example, about two spacings or more between adjacent projections or threads beyond the open distal tip of the cannula. More specifically, the rotational element advantageously further includes an elongated shaft having a proximal portion which is substantially smooth to allow sufficient annular space between the shaft and cannula for removal of material.
The cannula may be of any suitable size. However, in order to obtain the reduced invasiveness benefits of the present invention, it is preferred that the cannula size have an outer diameter of no greater than about 5 mm and more preferably about 2.0 mm or smaller.
It has unexpectedly been found that the present apparatus including such small size cannulas not only provide for reduced, or even micro, invasive procedures (which reduce surgical trauma and promote healing) but also are effective in removing materials from a body to achieve therapeutic benefits, for example, therapeutic removal of healthy or diseased breast tissue, fluidic cystic materials, soft tissue tumors, and the like.
In one embodiment of the invention, the open distal tip of the cannula is angled or is beveled with respect to a longitudinal axis of the cannula. Alternatively, the open distal tip is substantially perpendicular with respect to the longitudinal axis of the cannula.
The present apparatus advantageously includes a tissue collection chamber in communication, for example, fluid communication, with the cannula and structured to collect and contain material, for example breast tissue, that is passed through the cannula. The collection chamber preferably is structured to facilitate quantification and/or other analysis of the removed material. In one particularly useful embodiment, the collection chamber comprises a substantially transparent conical section removably engaged to a housing of the handpiece and preferably circumscribing a portion, for example, the proximal portion of the shaft of the rotational element.
The cannula and/or the rotation element, preferably both, advantageously are structured to be manually deformable, for example, to enable the physician to alter the normal configuration, for example, the normal substantially straight configuration, thereof to create a curved configuration if desired, for example, to deal with the material removal application at hand.
In another broad aspect of the present invention, methods of removing material from a breast of a human or an animal are provided. Such methods comprise placing into a breast of a human or an animal a cannula having an open distal tip and a rotational element disposed at least partially in the cannula and rotating the rotational element relative to the cannula, thereby at least assisting in drawing a material from the breast into the open distal tip of the cannula. The method preferably further comprises passing the material from the breast through the cannula. Apparatus in accordance with the present invention described herein, can be advantageously employed in accordance with the present methods.
The cannula used in accordance with the present methods preferably have outer diameters of about 5 mm or less, or about 2.0 mm or less.
The placing step of the present methods preferably includes percutaneously introducing the cannula into the human or animal breast, and positioning the open distal tip of the cannula in close proximity to the material to be removed. The cannula and rotational element preferably are sized and positioned relative to each other so that the rotating step is effective in drawing the material from the breast of a human or an animal into the open distal tip of the cannula. Preferably, the material from the breast is removed without applying additional suction or aspiration to the open distal tip of the cannula.
In one very useful embodiment, the rotating of the rotational element relative to the cannula is effective to draw the material into the cannula as a substantially single, continuous often times substantially cohesive piece. Thus, although some shearing and/or cutting of the material to be removed may occur in accordance with the present invention, for example, so that the removed material is compatible with the space within the cannula through which the material is to be moved proximally, the present apparatus and methods preferably are not based on cutting or chopping the material to be removed into small discrete segments.
The present methods preferably further comprise collecting the material removed and/or observing and/or otherwise testing the material removed.
Any suitable material can be removed from the body of a human or an animal using the present apparatus and/or methods. Preferably, such material to be removed can be effectively removed using the present apparatus and/or methods without employing or requiring additional suction or aspiration, beyond that formed or created by the rotation of the rotational element relative to the cannula.
Advantageously, the material to be removed is soft and/or semi-solid and/or a viscous flowable material and/or a material which is at least somewhat free to move toward a source of lower pressure or suction.
Incorporated herein by this specific reference are U.S. patent application for Micro-invasive Tissue Removal Device, having Serial No. 10/093,775, filed on even date herewith, and commonly assigned herewith, and U.S. patent application for Micro-invasive Nucleotomy Device and Method, having Serial No. 10/093,774 filed on even date herewith, and commonly assigned herewith.
Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent.


Improved reactive absorbent solutions for absorbing gaseous components are provided by incorporating weakly dissociating compounds in liquid absorbents. When the gaseous component to be dissolved is acid-forming, the absorbent solution should be alkaline, the weakly dissociated compound should be a weak acid or salt thereof, and the pH of the solution should approximate the pK.sub.A of the acid. When the gaseous component is base-forming, the liquid absorbent should be acidic, the weakly dissociating compound should be a weak base, and the pOH of the solution should approximately match the pK.sub.B of the weak base. The weakly dissociated compounds are 1 to 20 times more effective in increasing absorption rates, than additions of equivalent amounts of the primary acidic or basic reactants. Where the absorbed gas is desorbable, the addition of the weakly dissociating compounds has similar effects in increasing the rate of desorption.

This invention deals with improvements in the absorption of gases, using improved gas absorbents. More particularly it involves improvements in the absorption of gases which form ions upon dissolution in aqueous media.
A large number of gas absorption operations or processes have long been known. Generally they comprise contacting a liquid with a gas in order to transfer a soluble component from the gas phase to the liquid absorbent. Typically, the gas and liquid are contacted countercurrently in plate towers, packed beds, wetted wall columns, spraying systems, or mixers of various types. The intent may be to purify the gas stream, to recover gaseous products or reactants, to react the gaseous component with a material in the absorbent or with the absorbent itself, or to recover the gaseous component for other reasons.
The absorption of a gas into a liquid is caused by the diffusion of solute molecules into the liquid from the gas/liquid interface. Such diffusion is brought about by the random thermal motions of the molecules. Its effect is to redistribute the molecules from regions of higher to regions of lower concentration. It is common to speak of a concentration "driving force" as causing diffusion. This driving force at a given temperature is generally given for gas/liquid systems in terms of the difference between the amount of the component in the gas, as measured by its partial pressure, and the equilibrium pressure for a given amount of gas in the liquid. If the partial pressure of the gas is higher than the equilibrium pressure there will be absorption; if lower, desorption of the gas. Advantage is usually taken of this relationship in regenerating the absorbent liquid and recovering the dissolved gas. For example, gas can be absorbed in a liquid at high pressure, after which the saturated liquid can be exposed to low pressure which will allow the gas to come out of solution.
Where the gaseous component reacts in the absorbent solution, the number of moleucles of the component in solution is reduced as they are consumed by the reaction. Since the reaction reduces the amount of the component in the liquid, the driving force for diffusion of the component into the liquid is enhanced. A large number of processes of this type are known industrially. See Danckwerts, "Gas Liquid Reactions," pp 1 - 5 (McGraw Hill:1970). Some of the more familiar of these include the removal of carbon dioxide from gaseous mixtures by absorption in aqueous alkaline solutions, the removal of sulfur dioxide from flue gases and polluted atmospheres in caustic solutions, the absorption of ammonia in acid solutions, the absorption of hydrogen sulfide in alkali solutions, and others, such as the absorption of cyanic or acetic acid in basic solutions, or the absorption of gaseous organic amines in acid solution.
Because of the enhanced driving force obtained, systems in which the solute reacts in the absorbent are more efficient in absorbing the solute than systems which depend only on the solute's solubility in the absorbent. The controlling factors in reacting or enhanced absorption are the reaction rate and the diffusion rate. Where the reaction takes place slowly, the reaction rate may be the controlling factor in determining the rate of absorption. If the rate of reaction is relatively fast, as in most instances, the absorption rate is controlled by the resistances of the reactants to the diffusion necessary to bring the reactants together. The most common way to increase the rate of absorption in reactive absorbents is to increase the concentration of the reactant in the absorbent. For example, if the gaseous component reacts with OH.sup.- ions in aqueous absorbents, the reaction rate is increased by making the absorbent highly alkaline.
With non-reactive absorbent systems the solute or absorbate can be rather easily stripped or desorbed from the absorbent by purely physical processes. In reaction enhanced systems a second chemical reaction may be required to liberate the absorbed material. Where the first reaction is reversible this is usually not objectionable, since desorption can usually be achieved by placing the solute-bearing absorbent in a physical state which favors the operation of the first reaction in reverse, e.g., by removing unreacted solute from the system. In some instances however, desorption can only be obtained by addition of further reactants to the system or by other, more drastic measures.
While reactive gas absorption systems are much more efficient than purely physical absorption methods, they continue to suffer from a number of difficulties. The normal way to increase absorption rate in reactive systems is to load into the absorbent a greater amount of the reactants which act on the gas. Since such reactants are normally strong acids or bases, this addition results in extremely acidic or extremely alkaline absorbent solutions, which can cause significant corrosion problems with the operating equipment. Further, there is a very real limit as to how high the rate can be increased in such a manner, and the limits imposed by economics are even more stringent. In effect, this means that using reasonably efficient absorbent solutions, e.g. alkaline solutions of a pH of about 12, in presently available equipment, results in the non-absorption of a significant amount of the gaseous component, e.g. sulfur dioxide, which may then be released to pollute the atmosphere. In some cases, other more exotic and expensive systems must be used in order to further reduce the component content of the gas stream. In other cases such further processes are either too expensive or not available, and other restrictions, such as restrictions on burning high sulfur fuels, must be imposed. Other problems exist because of low or inadequate desorption rates in those processes where the solute or the absorbent are recovered or regenerated by desorption.
Accordingly, it is an object of the present invention to provide improved systems for gas absorption. It is a further object to provide systems for gas absorption in which the rate of absorption is substantially increased over certain previously known absorption systems. It is a further object to provide a gas absorption system in which the problems of handling highly concentrated acidic or basic absorbents can be avoided without any substantial loss in absorption. It is a further object to provide a gas absorption system in which the corrsion of the absorption equipment by the absorbent is minimized. It is a further object to provide gas absorption systems which operate at a substantially reduced cost compared to previously known systems. It is a still further object to provide absorbents which give high rates for absorbing such industrial pollutants as sulfur dioxide, hydrogen sulfide, nitrous oxide and other pollutants from the air, and thus provide greater ability to clean and maintain the environment. It is a further object to provide absorbent solutions which not only aid in the rate of absorption, but also aid in the rate of desorption, when the absorbent and/or the solute is to be recovered.
These and other objects and advantages, which will be apparent upon consideration of this disclosure or practice of this invention, are made possible by the use of certain absorbent systems described more fully below.
In accordance with the present invention the rate of absorption of gaseous compounds which react with hydrogen or hydroxyl ions to form ionic specie in aqueous solution is increased by addition of a weakly dissociated compound chosen and added in such an amount that the molar concentration of the hydrogen or hydroxyl ions is approximately numerically equal to the dissociation constant of the weakly dissociated compound. Where the gaseous compound reacts in water to form an acid, the solution in which it is dissolved should be basic and the weakly dissociated compound should be a weak acid or preferably the salt of a weak acid, the pK.sub.A of which approximately matches the pH of the alkaline solution. Where the gaseous component dissolves in water to form a basic solution, the absorbent solution should be acidic, and the weakly dissociated compound should be a weak base or preferably the salt of a weak base whose pK.sub.B matches approximately the pOH of the solution.
The rate increases obtained through the present invention are quite surprising. Depending upon the physical characteristics of the absorbing system and the reactants used, absorption rate increases obtained by addition of the weakly dissociating compound can be from one to as high as 15 or 20 times the rate increase obtained by the addition of an equivalent amount of the primary reactant. For example, in the absorption in sulfur dioxide in aqueous alkali, the normal method of increasing the absorption rate would be by adding an amount e.g. 0.05 mol/l, of additional alkali. The addition of that same amount of a weak acid, the pK.sub.A of which approximately matches the pH of the solution, will normally result in a rate increase which is at least equal to, and as high as 15 to 20 times that caused by addition of further alkali. This discovery allows the use of much less caustic or corrosive absorbents to get the same or even higher rates of absorption. Moreover, the rate increases obtained through the present invention and those obtained by addition of primary reactant are substantially additive, so that if it is more important to absorb greater amounts of the solute than it is to prevent corrosion, a compound with a very low dissociation constant can be used in conjunction with highly concentrated acidic or alkaline solutions to obtain substantially higher absorption rates than were previously possible.
As indicated above, the same or similar results can be obtained by the addition of a weakly dissociating base or its salts to acidic absorbents used to absorb base-forming gaseous components, in which case the pOH of the absorbent is preferably made to match the pK of the weakly dissociating base. Because of the greater industrial importance of systems in which alkaline absorbents are used to absorb acid-forming gases, such systems will be discussed in greater detail, it being understood that equivalent benefits will be obtained from the invention in the acidic absorbent systems.
As a practical matter, the weakly dissociating compound is normally added in the form of its salt, the alkali metal and alkaline earth metal salts being preferred. In alkaline absorbents, for example, the weak acid is normally added as its salt, since addition in acid from decreases the alkalinity of the absorbent slightly, However, rate increases are obtained in either event, and addition in acid form may be preferred in some cases.
Preferably the weak acid has a dissociation constant such that its pK is greater than 7, and the absorbent system is selected and/or adjusted so that the pH of the absorbent is approximately equal to the pK of the weak acid. Of course, in industrial systems such as packed beds, the pH of the absorbent may have considerable variation at different points in the system, e.g. between the top of the bed, where it contacts the gas stream for the first time, and the bottom of the bed, where the absorbent has absorbed a considerable amount of the gaseous component. In such instances, best results are normally obtained where the system is selected and/or adjusted so that the pK of the weak acid used is approximately midway between the pH's encountered at the top and the bottom of the column. With some solute/ absorbent systems, however, there may be a pH at which the driving force is minimized. The point at which this minimum occurs is often referred to as the pinch point. When the system has such a pinch point, it normally is preferable to choose a weak acid having a pK.sub.A which is at or near the pH of the pinch point.
Preferably the pH dos not differ from the pK of the acid by more than 1.5 units in alkaline absorbents according to the invention, more preferably not by more than 1.0 units. The highest absorption rates are obtained when the pH of the absorbent is equal to the pK of the acid, plus or minus 0.5 units.
The particular weak acid or salt thereof to be used depends upon the particular system under consideration. As indicated above, the pK of the acid should be above 7.0 although some benefits can be obtained in slightly alkaline absorbents by using a weak acid having a pK somewhat below 7.0, e.g. as low , as 6.0. Acids having pK's between about 8 and 13 are generally preferred in accordance with the present invention, with those having pK's of 9.5 to 12 being highly preferred. It should be noted that absorbent systems having their pH centered on pK's of 9 or higher become increasingly corrosive, and corrosiveness is one of the properties of the absorbent which it is desired to avoid. As indicated previously, the corrosiveness should be balanced against the desired speed of reaction. Organic acids are usable provided that the organic radical does not react or break down to an unacceptable degree under conditions faced in the process. Suitable acids or salts thereof include arsenic acid H.sub.3 A.sub.s O.sub.4 (pK.sub.2 = 6.98, pK.sub.3 = 11,50), arsenious acid HA.sub.s O.sub.3 (pK = 9.22), boric acid H.sub.3 BO.sub.3 (pK.sub.1 = 9.24, pK.sub.2 = 12.74 pK.sub.3 = 13.8), carbonic acid H.sub.2 CO.sub.3 (pK.sub. 2 = 10.25), germanic acid H.sub.2 GeO.sub.3 (pK.sub.1 = 8.5-9.5, pK.sub.2 = 12.72), hydrosulfuric acid H.sub.2 S (pK.sub.1 = 6.88, pK.sub.2 = 14.15), hypobromous acid HBrO (pK = 8.62), hypochlorous acid HClO (pK = 7.50), hypoiodous acid HIO (pK = 10.64), phosphoric acid, H.sub.3 PO.sub.4 (pK.sub.2 = 7.20, pK.sub.3 = 12.36), pyrophosphoric acid H.sub.4 P.sub.2 O.sub.7 (pK.sub.4 = 8.21), silicic acid, H.sub.2 SiO.sub.3 (pK.sub.1 = 9.77, pK.sub.2 = 11.80), and sulfurous acid, H.sub.2 SO.sub.3 (pK.sub.2 = 7.20). Aluminum hydroxide (pK = 12.2) can act as either a weak acid or a weak base. Weak acids which may themselves form gases which may desorb when faced with radical changes in pH, such as carbonic acid, sulfurous acid, hydrogen sulfide, etc., are not preferred as the weak acid in the absorbents of the present invention. Most highly preferred for the purpose of this invention is phosphoric acid and salts thereof, particularly the tertiary salts for very fast absorption rates in very alkaline solutions. At lower pH's, e.g. 8 - 9, pyrophosphoric acid salts also give particularly stable, non corrosive absorbent solutions yet also having high absorption rates. Generally, the amount of weak acid used in the absorbent may vary over wide ranges. Preferably it is present in about 0.05 to 1 mole per mole of base, more preferably from 0.2 to 0.5 moles per mole of base.
It has also been found that the presence of the weak acid in the alkaline absorbent not only aids in the absorption of the gas, but actually aids in the desorption of the gas when the absorbent is rejuvenated. Thus in those systems where it is desired to remove a gas from one stream and deal with it in a more concentrated form somewhere else, the addition of the weak acid aids in the reuse of the absorbent by providing high rates of absorption in the absorption step and high rates of desorption in the step where the gas is removed from the absorbent.
Without wishing to be bound by theory, it is believed that the absorption rate is increased, at least in part, because of the buffering action of the weak acid at or near the gas/liquid interface. Although the reactions of the gas component with hydroxyl ions greatly speeds the absorption rate, it is believed that when the gas is contacted with known alkaline absorbents, concentration gradients are built up as to both H.sup.+ and OH.sup.- content in the liquid near the liquid/gas interface. The OH.sup.- content at the interface is lower than the OH.sup.- content in the bulk of the liquid absorbent, because the hydroxyl ions are consumed, almost as soon as they become available, by the incoming SO.sub.2 molecules. Likewise, because of the reaction of the SO.sub.2 molecules with water, yielding H.sup.+ and HSO.sub.3.sup.- ions, there is a higher concentration of H.sup.+ ions in the liquid at the interface than in the bulk of the liquid. The reaction rate is decreased because both the SO.sub.2 and the H.sup.+ compete for reaction with whatever OH.sup.- becomes available via diffusion to the interface from the bulk of the liquid absorbent, or from dissociation of water molecules at the liquid/gas interface. The higher concentration of H.sup.+ also tends to repress the dissociation of water in the liquid.
When the weak acid of the present invention is present in the system and excess H.sup.+ becomes available, either from the dissociation of water or from the direct reaction of the acidforming gas with water, the anion of the weak acid (A.sup.-) consumes that excess by reacting with it to form the undissociated weak acid molecule (HA). The weak acid anion does not ordinarily react with the acid forming gas molecules, which are therefore left free to react with available OH.sup.- ions and thus speed absorption. The available OH.sup.- ions are also increased, because the removal of the excess H.sup.+ ions by the weak acid tends to spur dissociation of water.
The desorption stage of the cycle involves the buildup of similar, albeit opposite, gradients, and the weak acid is believed to speed desorption by reducing those gradients in a similar manner. Thus the low concentration or partial pressure of the gaseous component in the desorption gas phase forces the reaction with occurred during absorption to reverse, producing gas molecules and Oh.sup.- ions at the interface. A buildup of Oh.sup.- ions occurs at the interface, which slows down that reverse reaction. When a weak acid is present in the liquid, it decreases the OH.sup.- concentration at the interface by dissociating because of the lower H.sup.+ concentration to form H.sup.+ and A.sup.-. The H.sup.+ thus produced reacts with the excess OH.sup.- to form water, the OH.sup.- concentration gradient is reduced and the desorption reaction rate is increased because of the lower OH.sup.- concentration at or near the interface.
As mentioned above, the present invention is also applicable to the absorption of base-forming gas in acid absorbents, in which case a weakly dissociating base (pK.sub.b above 7, preferably 8 - 13) is incorporated in the absorbent. As also mentioned above, in that case the weak base is chosen so that its pK.sub.b approximately matches the desired pOH of the system, preferably the pOH being within 1.5 units, more preferably within plus or minus 0.5 - 1.0 units of the pK.sub.b. The amount of weak base used may be similar to the amounts of weak acid used in the other system, e.g. 0.05 to 1.0 mole per equivalent preferably 0.2 to 0.5 mole per equivalent of acid in the absorbent. Suitable weak bases include aniline (pK.sub.b = 9.42), beryllium hydroxide, (pK.sub.b = 10.30), hydroxylamine (pK.sub.b = 7.97), o- and p- phenylenediamine (pK = 9.63, 7.96 respectively), phenylhydrazine (pK = 8.80), piperazine (pK = 8.43); pyridine (pK = 8.77) and the o-, m-, and p-toluidenes (pK = 9.48, 9.26 and 8.70 respectively), or aluminum hydroxide, as mentioned above, with hydroxylamine being preferred. It is believed that the weak base in this system works mainly upon the liquid near the liquid/gas interface, in a manner analogous to that described above for the basic absorbent system.
It is particularly surprising that addition of buffer to the reactive absorbents of the present invention has such a pronounced effect on the absorption, in view of the fact that many of the gases absorbed therein themselves produce buffers upon dissolution. For example, when sulfur dioxide is dissolved in alkaline solution, bisulfite ions are produced by reaction between sulfur dioxide and hydroxyl ions, or between the sulfur dioxide and water. The bisulfite ion is itself a weak acid with a dissociation constant of about 6.24 .times. 10.sup.-8, for the following reaction: EQU HSO.sub.3.sup.- .revreaction. H.sup.+ + SO.sub.3 .sup.=
the bisulfite ion acts as a buffer, resisting changes in pH, since if excess hydrogen ions appear in the system, the above equation is driven to the left and they are consumed. If excess hydroxyl ions appear in the system, they react with and thus remove the hydrogen ions, driving the above equation to the right. It was not expected that the presence of an additional, different buffering compound in an absorbent which already contained a buffer would produce the substantial increases in absorption rate obtained through the present invention.
It should be noted that certain weak acids have been used in absorbents for absorbing carbon dioxide in aqueous media, albeit they were used for other reasons, and/or in considerably different systems. It has been known, for example to include amounts of arsenities or hypochlorites in such absorbents in order to catalyze the rather slow reaction of carbon dioxide in alkaline absorbents. See, e.g., Danckwerts, supra at 244 - 247. However, the use of such catalysts has been restricted to carbon dioxide systems, and no appreciable buffering effect would have been obtained from them, since in order to be useful catalysts they had to be essentially completely ionized. Id., at 245-46. Also, in Edsall and Wyman, "Biophysical Chemistry," Vol. I: 561-71, the authors reported a study of an attempt to simulate the ability of blood to desorb carbon dioxide in the lungs, using an imidazole buffer having a pK.sub.A of about 7.4. It was concluded that carbon dioxide absorbents containing a buffering weak acid were more efficient in taking up and giving off carbon dioxide than a simple bicarbonate system. However, the disclosure of Edsall et al. was strictly confined to the rather peculiar CO.sub.2 system, and only that system which approximated actual physilogical conditions of pH, strength, etc. It is indicated in Edsall et al. that the effect was optimally obtained for acids having pK.sub.a 's of 7 - 8, and minimal effects were indicated for pK.sub.a 's greater than 9. There was no suggestion that the same effects could be obtained in other-than-CO.sub.2 systems and no reason why the effect was obtained is given so that one might deduce that buffers might be useful in other systems. In German Patent No. 2,215,429, issued Oct. 5, 1972 to Celanese Corporation, (corresponding to later issued French 2,132,034) there is disclosed what is said to be an improved absorbent for carbon dioxide, comprising 0.6 to 4.0 moles of boric acid per mole of potassium hydroxide. This patent is strictly limited to a CO.sub.2 -KOH-H.sub.3 BO.sub.3 system at low pH.sub.3 s and no suggestion of utility in other systems is derivable from the patent. In sum, none of the prior art discloses or suggests the present invention. See Danckwerts, supra at 129, where it is indicated that in the aqueous absorption of SO.sub.2, the absorption rate is decreased by addition of acid or of axcess NaHSO.sub.3.


A packaged effervescent product is provided which includes a sachet surrounded by an outer package film sealing the sachet against water vapor transmission. The sachet is a cosmetic article which includes an effervescent cleansing composition of an acid material such as citric add and an alkaline material such as sodium bicarbonate. The composition is held within the sealed sachet or pouch. At least one wall of the pouch is water permeable. The outer package film is formed of a material which must have a breathability for carbon dioxide. Any carbon dioxide generated during storage is thereby allowed to slowly diffuse into the atmosphere while still minimizing the amount of water which may enter the package.

1. Field of the Invention
The invention concerns a packaged cosmetic effervescent cleansing product.
2. The Related Art
Cosmetic products are continuously being sought which differentiate themselves from competitors in some manner. Breakthroughs can arise through a difference in product form. A product form departure has been described in U.S. Pat. No. 6,063,390 (Farrell et al.). A wiping article is therein described which includes an effervescent cleanser composition held within a pouch formed from a pair of substrate sheets. At least one of those substrate sheets is required to be water permeable. The effervescent composition is a mixture of an add material such as citric add and alkaline material such as sodium bicarbonate. Water contact causes the combination to effervesce. Skin benefit agents and a dry surfactant may be formulated within the composition.
Maintenance of product stability is a major challenge with this product form.
U.S. Pat. No. 6,063,390 suggests that the wiping article or pillow be packaged within a moisture impermeable outer package such as a laminated foil bag to prevent activation of the effervescent system during storage.
While working with the disclosed system, the present applicants found that outer packaging for moisture penetration prevention aggravated another problem. Adventitious moisture within the formulation, rather than merely seepage from the environment, caused a certain level of effervescence to occur. Carbon dioxide gases were thus generated. The outer packaging intended as a moisture barrier now represented a hindrance to elimination of built up carbon dioxide gases.
It is an object of the present invention to provide an outer package for a pouch containing an effervescent composition wherein the package not only will prevent moisture from penetrating to the composition but allows for release of any carbon dioxide gases which may be generated during storage.
Other objects of the present invention would become more readily apparent from consideration of the following summary and detailed description.
It is to be noted that the subsequently described invention is broader than the objects or technical problems it is directed to solve.
A package cosmetic article is provided for cleansing body surfaces, the article including:
a pouch formed of walls, with at least one of the walls being water permeable, the pouch being sealed along all its perimeter; and
an effervescent cleanser composition in the form of an anhydrous dry solid being positioned within the pouch, the composition including:
(i) from about 1 to about 80% of an alkali material; and
(ii) from about 0.5 to about 80% of an acid material;
wherein the pouch is sealed within an outer package formed of a film having breathability for carbon dioxide.
It has been discovered through the present invention that outer packaging for cosmetic effervescent articles based on reaction of alkaline and acid materials must not only be a barrier protection from water vapor but also must be a breathable material allowing escape of any generated gases, especially carbon dioxide. Thus, the invention provides a sealed outer packaging material formed of a film having breathability. For purposes of this invention, breathability can be measured by ASTM D3985 intended to measure oxygen permeability but also useful for correlation to carbon dioxide permeability. When operated at 23xc2x0 C./0% Relative Humidity, carbon dioxide gas permeability should range from about 100 to about 3,000, preferably from about 150 to about 2,000, more preferably from about 200 to about 1500 cc per 100 square inches per 24 hours. Among preferred materials for the outer sealing package film are polypropylene, polyethylene, polyvinyl chloride and polycarbonate. Polypropylene is most preferred. The materials may be employed as a single layer or as a series of laminated layers. Some of the layers may be formed of a material other than the preferred types, but with proviso that the composite film meets the requirement for carbon dioxide breathability. Film thicknesses may range anywhere from about 0.1 to about 5 mil, preferably from about 0.5 to about 3 mil, optimally from about 1 to about 2.5 mil.
Another feature of films suitable for the outer package material is that they have a Vapor Transmission Rate for water according to DIN 53122 (measured at 23xc2x0 C./85% Relative Humidity) which ranges from about 0.001 to about 0.3, preferably from about 0.005 to about 0.1, more preferably from about 0.01 to about 0.1 grams per 100 square inches per 24 hours.
Most preferably, the film for the outer package material will be transparent. The sachet article will be viewable by a consumer through the transparent outer package. Aesthetics are therefore improved. Heat seals or adhesives may be employed along edges of the film to ensure a good seal.
Cosmetic wiping articles of the present invention when contacted with water billow to many times (more than 10 but often more than 40 times) their dry size when activated by water. The effervescent cleansing system exudes copious amounts of lather. A plumped xe2x80x9cpillowxe2x80x9d arises from the effervescent action. By careful control of the acidic and alkaline components, a squeaky clean rinsed feeling is felt on a user""s skin.
A component of compositions for generating effervescence within the pouch is that of an acidic material. Suitable for this purpose are any adds present in dry solid form. Especially appropriate are C2-C20 organic mono- and poly-carboxylic adds and especially alpha- and beta-hydroxycarboxylic acids; C2-C20 organophosphorus acids such as phytic acid; C2-C20 organosulfur acids such as toluene sulfonic add; and peroxides such as hydrogen peroxide. Typical hydroxycarboxylic acids include adipic, glutaric, succinic, tartaric, malic, maleic, lactic, salicylic and citric acids as well as acid forming lactones such as gluconolactone and glucarolactone. Most preferred is citric acid. Also suitable as acid material may be encapsulated acids. Typical encapsulating material may include water soluble synthetic or natural polymers such as polyacrylates (e.g. encapsulating polyacrylic acid), cellulosic gums, polyurethane and polyoxyalkylene polymers. By the term xe2x80x9cacidxe2x80x9d is meant any substance which when dissolved in deionized water at 1% concentration will have a pH of less than 7, preferably less than 6.5, optimally less than 5. These adds preferably at 25xc2x0 C. are in solid form, i.e. having melting points no less than 25xc2x0 C. Concentrations of the add should range from about 0.5 to about 80%, preferably from about 10 to about 65%, optimally from about 20 to about 45% by weight of the total composition.
Another component for generating the effervescent compositions of this invention within the pouch is that of an alkaline material. The alkaline material is a substance which can generate a gas such as carbon dioxide, nitrogen or oxygen, i.e. effervesce, when contacted with water and the acidic material. Suitable alkaline materials are anhydrous salts of carbonates and bicarbonates, alkaline peroxides (e.g. sodium perborate and sodium percarbonate) and azides (e.g. sodium azide). Preferably the alkaline material is sodium or potassium bicarbonate. Amounts of the alkaline material may range from about 1 to about 80%, preferably from about 5 to about 49%, more preferably from about 15 to about 40%, optimally from about 25 to about 35% by weight of the total composition.
By the term xe2x80x9canhydrousxe2x80x9d is meant the presence of no more than 10%, preferably no more than 3.5% and optimally no more than 1% water by weight of the total composition. Water of hydration is not considered to be water for purposes of the anhydrous definition. However, it is preferred to minimize, preferably to eliminate any water of hydration.
Advantageously the combined amount of acidic and alkaline materials will be at least about 1.5%, preferably from about 40 to about 95%, optimally from about 60 to about 80% by weight of the total composition.
An optional but useful component of the compositions according to the present invention may be that of a dry surfactant, preferably a dry surfactant solid at 20xc2x0 C. Most suitable for the present invention is sodium cocoyl isethionate. Other useful surfactants include sodium methyl cocoyl taurate and sodium lauryl sulfate. Surfactants may be of the anionic, cationic, nonionic, amphoteric, zwitterionic varieties and combinations thereof. Amounts of the dry surfactant may range from about 0.1 to about 30%, preferably from about 1 to about 30%, optimally from about 8 to about 15% by weight of the total composition.
A variety of skin benefit agents may be included to improve afterfeel properties. Advantageously these substances will be available as anhydrous dry powders. Alternatively these substances may be liquids deposited upon or into a powdered substrate (e.g. sodium bicarbonate or zeolite) to achieve a resultant dry flowing powder. Within the skin benefit agent scope are several categories of materials. These include emollients, antiaging actives, antibacterials and fungicides, skin lighteners, sunscreens and combinations thereof. Amounts of the skin benefit agents may range from about 0.001 to about 30%, preferably from about 0.1 to about 20%, more preferably from about 0.5 to about 10%, optimally between about 1 and about 5% by weight of the total composition.
Emollients may be in the form of natural or synthetic esters, silicone oils, hydrocarbons, starches, fatty acids and mixtures thereof. Typically the emollient may range in concentration from about 0.1 to about 35% by weight of the total composition.
Silicone oils may be divided into the volatile and nonvolatile variety. The term xe2x80x9cvolatilexe2x80x9d as used herein refers to those materials which have a measurable vapor pressure at ambient temperature. Volatile silicone oils are preferably chosen from cyclic or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to 5, silicon atoms.
Linear volatile silicone materials generally have viscosities less than about 5 centistokes at 25xc2x0 C. while cyclic materials typically have viscosities of less than about 10 centistokes.
Nonvolatile silicone oils useful as an emollient material include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers. The essentially non-volatile polyalkyl siloxanes useful herein include, for example, polydimethyl siloxanes with viscosities of from about 5 to about 100,000 centistokes at 25xc2x0 C. Among the preferred non-volatile emollients useful in the present compositions are the polydimethyl siloxanes having viscosities from about 10 to about 400 centistokes at 25xc2x0 C.
Among the ester emollients are:
(1) Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms. Examples thereof include isoarachidyl neopentanoate, isononyl isonanonoate, oleyl myristate, oleyl stearate, and oleyl oleate.
(2) Ether-esters such as fatty acid esters of ethoxylated fatty alcohols.
(3) Polyhydric alcohol esters. Ethylene glycol mono and di-fatty acid ester, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200-6000) mono- and di-fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol poly-fatty esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol esters.
(4) Wax esters such as beeswax, spermaceti, myristyl myristate, stearyl stearate and arachidyl behenate.
(5) Sterols esters, of which cholesterol fatty add esters are examples thereof.
(6) Triglycerides such as sunflower seed oil, maleated sunflower seed oil, borage seed oil and safflower oil.
Hydrocarbons suitable as emollients include petrolatum, mineral oil, isoparaffins and hydrocarbon waxes such as polyethylene.
Starches are also suitable emollients. Typical of this class is tapioca and arabinogalactan.
Fatty acids may also be suitable as emollients. The fatty acids normally have from 10 to 30 carbon atoms. Illustrative of this category are pelargonic, lauric, myristic, palmitic, stearic, isostearic, hydroxystearic, oleic, linoleic, ricinoleic, arachidic, behenic and erudc acids.
Antiaging actives are also useful as skin benefit agents. Included within this category are vitamins, retinoids and combinations thereof. Amounts of these materials may range from about 0.001 to about 20% by weight of the total composition. Suitable vitamins include ascorbic acid, Vitamin B6, Vitamin B12, tocopherol as well as salts and C1-C20 esters thereof. Suitable retinoids include retinoic acid as well as its C1-C22 esters and salts, retinol and C1-C22 fatty esters of retinol including retinyl linoleate.
Another class of antiaging actives are the alpha- and beta-hydroxycarboxylic acids and salts thereof. Representative of this group are glycolic acid, lactic add, malic add, hydroxyoctanoic acid and mixtures of these as well as their salts. Suitable salts are the alkalimetal, ammonium and C1-C10 alkanol ammonium salts.
Antibacterials and fungicidals may also be included as skin benefit agents. Representative of these categories are triclosan, triclocarban, hexetidene, gluconates, zinc salts (e.g. zinc citrate and zinc phenolsulfonate) and combinations thereof.
Skin lighteners may also be included under the skin benefit agents. Typical of this category are niacinamide, kojic acid, arbutin, vanillin, ferulic acid and esters thereof, resorcinol, hydroquinone, placental extract and combinations thereof.
Sunscreens may also be included as skin benefit agents. Particularly preferred are such materials as ethylhexyl p-methoxycinnamate, available as Parsol(copyright) MCX, and benzophenone-3, also known as Oxybenzone. Inorganic sunscreen actives may be employed such as microfine titanium dioxide, polyethylene and various other polymers. Amounts of the sunscreen agents will generally range from 0.1 to 30%, preferably from 2 to 20%, optimally from 4 to 10% by weight.
Adjunct functional agents may also be incorporated into compositions of the present invention. These include electrolytes, thickeners and mixtures thereof. Amounts of these substances may range from about 0.1 to about 20%, preferably from about 0.3 to about 10%, optimally between about 0.5 and about 5% by weight of the total composition.
Electrolytes may be selected from alkali, alkaline earth or ammonium salts of phosphates, silicates, halides, sulphates and mixtures thereof. Typical phosphates are potassium polymetaphosphate, sodium tripolyphosphate, sodium tetrapyrophosphate, sodium or potassium pyrophosphate and sodium hexametaphosphate. Most preferred is potassium polymetaphosphate available as Lipothix 100B(copyright) which is a 70:30 mixture of potassium polymetaphosphate and sodium bicarbonate, available from Lipo Chemicals, Inc., Paterson, N.J. Preferred sulphates are the magnesium sulphates.
Thickeners which may improve afterfeel properties on skin include inorganic or organic substances. A particularly preferred inorganic thickener is sodium magnesium silicate commercially available as Optigel SH(copyright). Organic thickeners include alginic acid as well as sodium and calcium alginates, sodium carboxymethyl cellulose, hydroxypropyl methylcellulose, hydroxypropyl cellulose, hydroxyethyl cellulose and combinations thereof. Most preferred is alginic acid commercially available as Kelacid(copyright) from Sud-Chemie Rheologicals, Louisville, Ky. Alginic acid is highly effective at removing the slimy feel associated with deposits of alkaline material which are not fully rinsed away from the skin. Amounts of the thickener may range from about 0.1 to about 20%.
Polysaccharides useful in this invention are dry solid anhydrous substances such as sorbitol, sugars, (such as trehalose) starches, modified starches (e.g. aluminum octenyl succinate) and mixtures thereof. Most preferred is sorbitol.
Deposition aids may also be incorporated in compositions of the present invention. These assist in depositing skin benefit agents onto the skin surface. Particularly effective are cationic monomers and polymers for this purpose.
Most preferred for purposes of this invention are Polymer JR and cationic guar gums such as Jaguar C13S(copyright) which is guar hydroxypropyltrimonium chloride. Amounts of the deposition aid may range from about 0.01 to about 1%, preferably from about 0.05 to about 0.5%, optimally from about 0.1 to about 0.3% by weight.
Advantageously an emotive agent such as a fragrance and/or botanical extract are included with the effervescent cleansing composition. Fragrances and botanicals are often liquids. For this reason it is necessary to uniformly distribute and allow absorption of liquid components into the solid powder. One method of best achieving this is to spray these liquids onto the solids. Amounts of the fragrance and/or botanicals combined may be at levels from abut 0.1 to about 3%, preferably from 0.5 to 2%, optimally from 0.8 to 1.5% by weight of the total composition.
The term xe2x80x9cfragrancexe2x80x9d is defined as a mixture of odoriferous components, optionally mixed with a suitable solvent diluent or carrier, which is employed to impart a desired odor. Particular preferred odoriferous components are cyclic and acyclic terpenes and terpenoids. These materials are based upon isoprene repeating units.
Preservatives can desirably be incorporated into the cosmetic compositions of this invention to protect against the growth of potentially harmful microorganisms. Suitable traditional preservatives for compositions of this invention are alkyl esters of para-hydroxybenzoic acids. Other preservatives which have more recently come into use include hydantoin derivatives, propionate salts, and a variety of quaternary ammonium compounds. Cosmetic chemists are familiar with appropriate preservatives and routinely choose them to satisfy the preservative challenge test and to provide product stability. Particularly preferred preservatives are phenoxyethanol, methyl paraben, propyl paraben, imidazolidinyl urea, sodium dehydroacetate and benzyl alcohol. The preservatives should be selected having regard for the sue of the composition and possible incompatibilities between the preservatives and other ingredients in the emulsion. Preservatives are preferably employed in amounts ranging from 0.01% to 2% by weight of the composition.
Natural vegetable materials from renewable resources are often desirable in cosmetic compositions. For instance, cosmetic compositions of the present invention may include beta-glucan derived from oats, commercially available under the trademark Microat SF from Nurture Inc., Missoula, Mont.
Colorants may also be included in compositions of the present invention. These substances may range from about 0.05 to about 5%, preferably between 0.1 and 3% by weight.
Effervescent cleansing compositions of this invention will be placed within a pouch formed between a first and second flexible substrate sheet, preferably at least one of these being a flexible sheet At least one of the sheets must be water permeable, most preferably both sheets should have water permeability. For definitional purposes, first and second sheets can be folded-over panels of a single unitary sheet Suitable materials for forming sheets may be rayon, polyester, polyethylene, polypropylene, cotton or any combination thereof. These sheets may be woven or non-woven. Most preferred is a non-woven rayon. Cellulosic paper fiber substrates are best not employed because of their insufficient wet-strength although they may be blended with other fibers referenced above; it is important that the substrate sheets are not readily torn open through consumer rubbing of the article. Unlike laundry sachet articles, pouches of the present invention should not rupture to allow dispersion of their granular contents into wash water. Rather it is intended for all cleanser composition components to exit by dissolution through the permeable walls of the pouch.
Skin surfaces against which articles of the present invention are useful include face, body, scalp, axilla and even legs/feet. When the article is a foot cleanser, it would be advantageous for the pouch on one of its sides to be coarse while the second of the sheets may be soft and gentle. An abrasive non-woven flexible sheet in a foot cleanser product is useful for rubbing against calluses while the second sheet of the pouch remains smooth.
Articles according to the present invention may be formed in the following manner. Constituents of the effervescent cleansing composition are placed into a dry mill or similar apparatus and blended until a uniformally distributed powder results. Thereafter, fragrance/botanical component as a Phase B is sprayed into the dry mill with concurrent agitation of the powdered composition.
A continuous roll of first substrate sheet is unwound from a source roll over a moving conveyer belt. The effervescent cleansing composition is placed into a hopper positioned over the conveyer belt. A discrete charge of powdered composition is regularly placed on the first substrate sheet at a location directly under a nozzle of the hopper. A second substrate sheet is then in register placed over that of the loaded first substrate sheet. At this point all four corners defining a rectangle or square are sealed in register trapping the effervescent cleansing composition within. Cutters then separate one sealed section from another thereby forming the wiping article.
Ultrasonic welding may be employed as an alternative to heat-sealing of the first and second substrates together. Thread stitching, glue application or other closure mechanisms may also be utilized.
One or more of the wiping articles are then packaged, within an outer packaging film sheet which meets the water and carbon dioxide Vapor Transmission Rate hereinabove described. Particularly useful are polypropylene clear transparent films. A single sheet of such film is wrapped around the sachet wiping article and the edges of the film are heat sealed to enclose the sachet.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material are to be understood as modified by the word xe2x80x9caboutxe2x80x9d.
The term comprising is meant not to be limiting to any subsequently stated elements but rather to encompass non-specified elements of major or minor functional importance. In other words the listed steps, elements or options need not be exhaustive.

Packaged cosmetic effervescent cleansing pillow

Unilever Home and Personal Care USA, division of Conopco, Inc.