Medicated catamenial tampon

Abstract

A medicated catamenial tampon, comprising a resilient foam corpus and a medicament-bearing hydrophobic non-woven overwrap which is permeable to catamenial fluids, adapted for non-menstrual as well as menstrual delivery of medicant to control and treat vaginal area disorders.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an improved medicated catamenial tampon, characterized by enhanced delivery and vaginal retention of medicament, which may be comfortably inserted and withdrawn for treatment during both menstrual and non-menstrual periods.

The normal healthy state of the lower female genital organs is maintained by a delicate balance of hormonal, cytologic and bacterial factors which develop at puberty. This balance is easily disrupted, making the vagina and related organs unusually susceptible to infectious disease. Such infection is generically known as vaginitis. Although the conditions conducive to vaginitis are not fully understood, it is believed that the danger of infection increases during menstruation. At this time during the female cycle a slightly alkaline pH is frequently established with attendant sloughing of epithelial tissue. Such conditions favor the overgrowth of putrefactive microorganisms, introduced, for example, through careless handling of catamenials, resulting in severe inflammation.

One of the primary obstacles to effective control and treatment of vaginitis is the difficulty of delivering adequate dosages of medicament to the afflicted areas during the non-menstrual period. Since, as previously discussed, the likelihood of vaginitis increases during menstruation, the usual approach to treatment concentrates on controlling the infection at that time. However, even when controlled during menstruation, potentially infectious microorganisms continue to survive into the non-menstrual cycle. These "residual" microorganisms, unless controlled, are free to cause continuing inflammation or reoccurrence of infection during subsequent menstrual and non-menstrual periods. The folded convoluted structure of the vagina makes delivery of medication difficult and painful, particularly during non-menstrual periods when the naturally lubricating and spreading catamenial fluids present during menstruation are nearly absent.

Heretofore, vaginitis has been treated by a variety of medicant delivery techniques. For example, medicaments in the form of ovules have been introduced by hand; medicaments in the form of foams or ointments have been introduced by syringe; and medicaments have been introduced by impregnation on catamenial devices. Since vaginitis tends to flare up most noticeably during menstruation, the use of medicated tampons has received particular attention as a convenient form of treatment.

The prior art has suggested a variety of medicated, wrapped and unwrapped, catamenial tampons. The predominant approach has been to impregnate the tampon corpus with medicament. A less common approach has been to overwrap the tampon corpus with a medicament-impregnated covering. U.S. Pat. No. 3,091,241 to W. R. Kellett exemplifies this latter approach. In any event, previously known medicated tampons suffer several shortcomings. In particular, such medicated tampons are fabricated from compressed absorptive fibers. Accordingly, such tampons are essentially rigid cylindrical tubes designed to reform in the vaginal cavity when wetted by absorbed catamenial fluid. Their rigid structure, however, makes non-menstrual use both painful and ineffective.

Accordingly, it is the primary object of the instant invention to provide a compliant comfortable medicated tampon, having enhanced medicament delivery and retention, which can be worn during both menstrual and non-menstrual periods of the female cycle.

It is a further object of the instant invention to provide a medicated tampon which can be easily and painlessly inserted, worn, and withdrawn.

These and other objects are achieved by the instant invention as will become readily apparent from the following disclosure.

SUMMARY OF THE INVENTION

Objects of the present invention are achieved by providing a medicament-bearing catamenial tampon, comprising: a resilient foam corpus having a modulus of compression which allows it to be reformed following insertion to conform to the irregularities of the vaginal wall; and a medicament-bearing hydrophobic non-woven overwrap which is permeable to vaginal fluids, wherein said medicament comprises a safe and effective amount of a therapeutically active agent for control of vaginal disorders and a vaginal fluid-soluble binding lubricant having a melting point of from about 38.degree. to 50.degree.C.

BRIEF DESCRIPTION OF THE DRAWINGS

The several features of the present invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 represents a cross sectional view of a preferred medicated tampon, as described herein, housed in a tubular inserter; and

FIG. 2 represents a cut-away perspective view of a preferred medicated tampon, as described herein.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention, broadly speaking, is based upon the unexpected discovery that an improved medicated catamenial tampon can be prepared by providing a medicament bearing catamenial tampon, comprising: a resilient foam corpus having a modulus of compression which allows it to be reformed following insertion to conform to the irregularities of the vaginal wall; and a medicant bearing hydrophobic non-woven overwrap which is permeable to vaginal fluids, wherein said medicament comprises a safe and effective amount of a therapeutically active agent for control of vaginal disorders and a vaginal fluid-soluble binding lubricant having a melting point of from about 38.degree. to about 50.degree.C.

A medicated tampon to be fully satisfactory for present purposes must be acceptable to the user, and effective in treating vaginal disorders. To be acceptable to the user, it must be, among other things, aesthetically pleasing, easily and unobtrusively carried, comfortably inserted and removed, and absorptive. To be effective in treating vaginal disorders, the tampon must be able to deliver medication directly to the afflicted areas during both menstrual and non-menstrual periods and must promote vaginal retention of the medication. Since the superlatives of some of these aspects tend to be mutually exclusive, a consumer acceptable and effective medicated tampon must be a balance of all of these traits.

To achieve an optimum balance of desirable properties, the medicated tampon of the present invention comprises two critical structural components. Referring to FIGS. 1 and 2, the medicated tampon 15 of the present invention comprises a reslient foam corpus 10 and a medicament-bearing hydrophobic non-woven overwrap 11.

The Foam Corpus

The resilient foam corpus 10 can be prepared from a variety of materials in a variety of shapes. However, in order to insure delivery of medication to the afflicted area of the vagina and in order to conform to the surface of the vagina when worn either menstrually or non-menstrually, the foams suitable for use herein should have a modulus of compression which allows the tampon to be reformed following insertion to conform to the irregularities of the vaginal wall. In other words, suitable foams will expand, when dry, to substantially fill the vaginal cross-section. The term "dry-expansion" as used herein is intended to describe that property of suitable foams which allows the tampon corpus to conform to the vagina without relying on the actions of fluids to release compression set which may have taken place within the tampon prior to insertion. Dry-expanding foams allow the medicated tampon to be worn non-menstrually yet achieve adequate vaginal contact so as to insure delivery of medication to afflicted areas.

Suitable preferred dry-expanding foams used as tampon corpus 10 should have a dry modulus of compressibility as defined in ASTM Test D1564, Compression Load Deflection Test (Suffix D), of from abut 0.2 pounds per square inch to about 0.6 pounds per square inch, preferably about 0.4 pounds per square inch, and a wet modulus of compressibility to attain 75 percent of the original dry thickness ranging from about 0.1 to 0.3 psi, preferably about 0.2 psi. The ASTM Compression Load deflection Test consists of measuring the load necessary to produce a 25 percent compression over the entire top area of the foam specimen. In addition, suitable preferred foams should have a shape modulus of compression, i.e., the unidirectional pounds force required to deform the tampon to its collapsed state, such that the tampon will assume its collapsed state under the forces exerted within the vagina. The shape modulus should be greater than about 0.05 pounds so the tampon has some tendency to maintain its shape when compressed. The shape modulus should not be greater than about 1.0 pound because then the tampon becomes too difficult to deform and retains its round cross section which is not as good for tampon performance because the vaginal walls do have some beam strength and do not drape perfectly; therefore, if the vagina is not fully distended by a tampon, a greater percentage of the vaginal wall is in contact with a collapsed, i.e., flattened, tampon than is in contact with an uncollapsed, i.e., round, tampon, due to the vaginal wall contilevering beyond the lateral edges of the tampon. The shape modulus is dependent upon the density and elasticity of the material and the shape of the tampon.

In addition to the above-described dry-expansion properties, suitable foams for use herein are preferably mensesphilic, i.e., have surface characteristics such that vaginal fluids tend to spread readily or spontaneously on the surface and in the capillaries of the foam. As previously discussed, the vagina is most susceptible to infection during menstruation. Thus, it is desirable to utilize a vaginal fluid-absorbent tampon corpus as a convenient vehicle for the medicament-bearing overwrap. Since vaginal fluids are primarily aqueous solutions, materials onto and into which it spreads readily could be loosely described as hydrophilic. Hydrophilicity, and thus mensesphilicity, is fully detailed in the American Chemical Society publication entitled Contact Angle, Wettability and Adhesion, edited by Robert F. Gould (1964), incorporated herein by reference. In general, hydrophilicity is defined by contact angles, and surface tensions of the fluids and solids involved.

The contact angle is defined as the angle formed between two planes as measured in the liquid, i.e., the plane tangent to the liquid air interface at the point of liquid-air-solid mutual contact and the plane of liquid-solid contact at the liquid-air-solid mutual contact. The smaller this angle is, the less is the force required to spread the liquid and at a contact angle of zero, the fluid tends to spread spontaneously and without limit on the surface of the solid. In general, materials having a contact angle between them of less than 90.degree. can be described as -philic (attractice toward each other) and those having angles greater than 90.degree. between them as -phobic (repellent toward each other). Therefore, a mensesphilic material can be definitely but broadly defined as one with which menstrual fluid makes a contact angle of less than 90.degree..

The contact angle between a fluid and a solid, and consequently the philicity or phobicity of the solid for the liquid, is related to the ratio between the surface tension of the fluid and the solid. In practice, the method for determining surface tension of the solid is to compare contact characteristics of the solid against various liquids. This method is more completely described on p. 12, et seq., of the above mentioned publication. The value derived from this method is usually called the critical surface tension of the solid. If the ratio is greater than 1:1, i.e., the surface tension of the fluid is greater, the solid is -phobic. If the ratio is less than 1:1, i.e., the surface tension of the solid is greater, the solid is -philic. As the ratio becomes smaller, the solid is more and more -philic.

Menstrual fluid has a surface tension range of about 35 to 60 dynes per centimeter. It will have a contact angle of less than 90.degree. and will tend to spread spontaneously on a solid which has a critical surface tension value greater than its surface tension.

Water has a high surface tension which is about 72 dynes per centimeter and would be apt to spread spontaneously only on solids with critical surface tensions higher than 72 dynes per centimeter unless the solid's surface had changed through an interaction with the water. Therefore, hydrophilicity is not a precise definition with respect to the affinity of a solid for menstrual fluid. The contact angle between menstrual fluid and a solid or the ratio between the surface tension of the menstrual fluid and the critical surface tension of the solid is definitive of their mutual affinity and tendency toward spontaneous wetting. Since the surface tension of water is higher than that of menstrual fluid, any solid which is hydrophilic is also usually mensesphilic.

Although flexible polyurethane foams in general can be used herein to form the tampon corpus 10, there are drastic differences in performance between tampons having the tampon corpus prepared from conventional mensesphobic flexible polyurethane foams and mensesphilic flexible polyurethane foams. The differences are sufficiently great that mensesphilic polyurethane foams are highly preferred. Even within mensesphilic polyurethane foams there is a wide variation in performance; and it is most preferred to use mensesphilic polyurethane foams having good wet swell properties since the total volume of vaginal fluids which can be contained by a tampon corpus is related to its eventual size and yet one prefers to have a tampon of minimal size for ease of insertion. Minimal size is especially important where one uses an inserter of the type that requires the tampon to be pushed out through a cylindrical portion of the inserter (see FIG. 1). Another desirable quality is low compression set when radially compressed within an inserter since dry expansion after insertion provides better bypass control as well as medicant delivery. It is, of course, desirable to use foams having a minimum content of extraneous soluble materials since the product may be retained in the body for a considerable period of time and retained soluble extraneous materials could interfere with the desired therapeutic value of the medicated tampon.

In general, the flexible polyurethane foams used in the preferred embodiment of this invention will be prepared from a reaction mix comprising a polyhydroxy compound which will be, at least in part, a polyether but which may be also, in part, a polyester, and mixtures of polyester and polyether compounds. The following patents, all of which are incorporated herein by reference, disclose mensesphilic polyurethane foams which are especially desirable. Joerg Smabeth, et al., U.S. Pat. No. 3,586,648, patented June 22, 1971; Alexis Archipoff, et al., U.S. Pat. No. 3,573,234, patented Mar. 30, 1971; Joerg Sambeth, et al., U.S. Pat. No. 3,560,416, patented Feb. 2, 1971; Charles H. Hofrichter, et al., U.S. Pat. No. 3,463,745, patented Aug. 26, 1969; Stanley I. Cohen, et al., U.S. Pat. No. 3,457,203, patented July 22, 1969; Joerg Sambeth, et al., U.S. Pat. No. 3,451,954, patented July 22, 1969; Joerg Sambeth, et al., U.S. Pat. No. 3,451,953, patented June 24, 1969; Joerg Sambeth, et al., U.S. Pat. No. 3,432,448, patented Mar. 11, 1969; Rudolf Merten, et al., U.S. Pat. No. 3,388,081, patented June 11, 1968; Bernard Rabussier, U.S. Pat. No. 3,385,803, patented May 28, 1968; James A. Calamari, U.S. Pat. No. 3,164,565, patented Jan. 5, 1965; Morris V. Shelanski, et al., U.S. Pat. No. 3,098,048, patented July 16, 1963; Carl V. Strandskov, U.S. Pat. No. 3,042,631, patented July 3, 1962; Fritz Schmidt, et al., U.S. Pat. No. 3,007,883, patented Nov. 7, 1961; Harold L. Elkin, U.S. Pat. No. 2,965,584, patented Dec. 20, 1960; Erwin Windemuth, et al., U.S. Pat. No. 2,948,691, patented Aug. 9, 1960; Elekal, British Pat. No. 1,180,316, patented Feb. 4, 1970, Vereinigt Papierwerke Schickedanz & Co., French Pat. No. 1,350,709, patented Dec. 23, 1963.

Other mensesphilic polyurethane foams can also be used, including the foams disclosed in the following patents which are also incorporated herein by reference. George Shkapenko, et al., U.S. Pat. No. 3,535,143, patented Oct. 20, 1970; John G. Simon, et al., U.S. Pat. No. 3,508,953, patented Apr. 28, 1970; Whitney R. Adams, et al., U.S. Pat. No. 3,458,338, patented July 29, 1969; John R. Caldwell, et al., U.S. Pat. No. 3,418,066, patented Dec. 24, 1968; Joerg Sambeth, et al., U.S. Pat. No. 3,413,245, patented Nov. 26, 1968; Lyle W. Colburn, U.S. Pat. No. 3,404,095, patented Oct. 1, 1968; Fred W. Meisel, et al., U.S. Pat. No. 3,382,090, patented May 7, 1968; Yvan Landler, et al., U.S. Pat. No. 3,326,823, patented June 20, 1967; Ming Chih Chen, U.S. Pat. No. 3,249,465, patented May 3, 1966; Sotirios S. Beicos, U.S. Pat. No. 3,149,000, patented Sept. 15, 1964; John Bugosh, et al., U.S. Pat. No. 3,094,433, patented June 18, 1963; Karl Goldann, U.S. Pat. No. 2,998,295, patented Aug. 29, 1961; Marvin J. Hurwitz, et al., U.S. Pat. No. 2,990,378, patented June 27, 1961; John Bugosh, U.S. Pat. No. 2,920,983, patented Jan. 12, 1960; and William R. Powers, et al., U.S. Pat. No. 2,900,278, patented Aug. 18, 1959.

In general, it is preferred to prepare the tampon corpus 10 from a mensesphilic foam which is at least partially mensesphilic by virtue of the reactants; but it is also desirable in many instances to add additional mensesphilic materials to the foam to increase either the mensesphilicity of the foam or the ability of the foam to hold liquid and resist compressive failure, i.e., squeeze out. A mensesphilic, polyurethane foam used should have a critical tension of at least about 60 dynes per centimeter and preferably greater than about 72 dynes per centimeter.

As stated before, it is especially desirable for the foam to have good wet swell properties, i.e., undergo wet swell at one atmosphere of pressure, being at least about 25 percent and preferably about 100 percent. A minimum wet swell of about 25 percent is necessary to appreciate advantages of wet swell. Examples of polyurethane foams which have good wet swell properties include those disclosed in U.S. Pat. No. 3,164,565, referred to hereinbefore and Morris V. Shelanski, et al., U.S. Pat. No. 3,098,048, patented July 16, 1963; those disclosed hereinafter in FOAMS I, II, and III; and the product sold commercially as Scott Hydro-Foam.sup.TM by Scott Paper Company Foam Division, Eddystone, Pa. As discussed hereinbefore, it is desirable to remove extraneous materials from these foams, for example, by washing them with water, to avoid any irritant or toxicity problems that these extraneous materials may cause.

The following FOAMS I, II, and III are mensesphilic foams which are preferred for use as the tampon corpus 10 of the medicated tampons of this invention. They were made from a polyether polyol having an appreciable level of polyethylene oxide built into the molecule. For this purpose, a polyether incorporating 40-60 wt. percent polyethylene oxide and 60-40 percent polypropylene oxide seems to be about optimum.

FOAM I

An intimate mixture of

INGREDIENT PARTS BY WEIGHT COMMENT __________________________________________________________________________ Polyether Polyol.sup.1 100.00 Non-ionic Surfactant.sup.2 15.00 Wetting agent n-Ethyl Morpholine 0.10 Foaming catalyst Stannous Octoate (T-9) 0.40 Polymerization catalyst Silicone Surfactant.sup.3 4.00 Foam stabilizer Water 4.50 Blowing agent __________________________________________________________________________ .sup.1 Dow SA-1421 available from Dow Chemical Company, Midland, Michigan .sup.2 Polyethylene glycol .sup.3 Silicone L-532 available from Union Carbide, Charleston, West Virginia

was prepared at room temperature. These ingredients were mixed in a food type blender at high speed for about 1 minute. Then 48.3 parts by weight of toluene di-isocyanate (TDI), comprising 80 percent 2,4 and 20 percent 2,6 isomers, were quickly added and mixed at high speed in the blender for 2 to 5 seconds. The entire mixture was then poured quickly into a form wherein the foaming proceeded. Upon completion of the foaming, within 90 seconds, the gelled foam was further cured in an oven at 250.degree.F. for 2 hours. This post cure is necessary for small batches but not for large batches. The foam thus formed was flexible, resilient, and mensesphilic.

FOAM II

A polyurethane foam was prepared using the procedure of FOAM I, but instead of 48.3 parts by weight of TDI, 38 parts by weight were used. The procedure used for pouring, foaming, and post-foaming cure was the same as in FOAM I.

The foam thus formed was flexible, resilient, mensesphilic, and wet swelling.

FOAM III

A polyurethane foam was prepared using the procedure of FOAM I, but instead of 48.3 parts by weight of TDI, 52 parts by weight were used. The procedure used for pouring, foaming, and post-foaming cure was the same as in FOAM I.

The foam thus formed was flexible, resilient mensesphilic, and wet swelling.

In addition to the above formulations, acceptable foams for use as tampon corpus 10 can be made in the complete absence of the non-ionic surfactant, n-ethyl morpholine, and silicone surfactant. By the same token, the levels of foaming catalyst, polymerization catalyst, and foam stabilizer may be increased to several times the values stated while still producing a wet swellable mensesphilic foam. The amount of water may be varied from 0 to 9 parts per hundred as a method of varying the density of the foam. Similarly, an organic blowing agent such as Freon-11 may be used instead of water/TDI yielding CO.sub.2 as the blowing agent.

Having thus described the principal characteristics of suitable foams for use as the tampon corpus 10, it is clear that a variety of tampon corpus configurations may be readily adapted for use herein. For example, the commonly assigned U.S. Pat. No. 3,815,601 granted June 11, 1974, entitled "Catamenial Aggregate Absorbent Body", and U.S. Pat. No. 3,794,029, granted 2/26/74 to B. A. Dulle (incorporated herein by reference) disclose resilient foam tampons which are suitable for use herein as tampon corpus 10. The above-mentioned U.S. Pat. No. 3,815,601 dicloses a particularly preferred tampon corpus configuration, wherein the corpus comprises a plurality of discrete foam pieces rather than a unitary body. Various other suitable configurations will be readily apparent to those skilled in the art.

The Medicament-Bearing Overwrap

The second critical component of the present invention is a medicament-bearing hydrophobic non-woven overwrap which is permeable to vaginal fluids. Referring again to FIGS. 1 and 2, the resilient foam corpus 10 of tampon 15 is wholly encased within the overwrap 11 which has applied to its surfaces a medicament 12. The overwrap can be formed from an essentially rectangular piece of material by bringing two opposite edges of the rectangular piece together to form a tube having a longitudinal seam which is secured by any of numerous well-known methods, such as sewing or glueing. One end of the tube can then be gathered radially inwardly and fastened to form a closure, such as distal end 13. This closure can be held by any of many various well-known means such as glueing, sewing, or tying with a string. At this stage the overwrap is tubular with distal end 13 closed and proximal end 16 open. The foam corpus is then placed within the overwrap and the proximal end 16 is gathered radially inwardly and fastened to form a closure. Thus, the overwrap 11 wholly encases the foam corpus 10.

A withdrawal string 14 is attached to the overwrap of the assembled tampon. The withdrawal string 14, of course, provides a means of withdrawing the tampon from the vagina following delivery of the medicant or when soiled, whichever occurs first.

The fit of overwrap 11 about the tampon corpus 10 is preferably loose to a degree rather than tight and can be described by a packing factor or a volume-length factor in conjunction with an overwrap cross-sectional area. It is advantageous to make the overwrap 11 somewhat loose about the tampon corpus 10 so that the overwrap is essentially unstressed. A loose overwrap makes the tampon look and feel fluffy and soft, i.e., aesthetically pleasing. A loose overwrap also promotes absorption characteristics and insertion, wearing, and removal comfort.

The fit of the overwrap 11 about the corpus 10 also affects ejection force such that, with equal amounts of absorbent material, the ejection force is generally lower if the packing factor is higher, i.e., if the overwrap fit is tighter. For this reason and others explained hereinafter, the looseness of overwrap 11 about corpus 10, i.e., packing factor, is critical to achieve an optimum balance of certain desirable tampon characteristics. A loose overwrap about a tampon corpus of low modulus of compression to give a packing factor within a range defined infra will promote removal comfort, i.e., lack of discomfort when the tampon is removed from a vagina. Removal comfort is enhanced because the corpus will compress to conform to the introital orifice; thus dilation of the introitus during removal is gradual and easier due to the low modulus of the tampon corpus. Thus, since the introitus is a constricting band of muscles which can be dilated, a soft, comfortable tampon will take on a wedge shape having a gradually increasing diameter to gradually dilate the introitus, rather than sharply dilating the introitus, to enhance the removal comfort of the tampon. Removal comfort is particularly desirable inasmuch as the medicated tampons herein are intended for use during non-menstrual periods.

The looseness of the overwrap can be more precisely defined in terms of a volume packing factor. The volume packing factor is the volume of the corpus divided by the maximum volume enclosable by the overwrap, i.e., cubic inches of foam corpus per cubic inches within the overwrap. The volume of absorbent material as used in the packing factor can be calculated for any specific tampon by dividing the weight of the corpus by the density. A weight packing factor can also be determined for tampons of this invention by dividing the weight of the corpus 10 by the maximum volume enclosable by the overwrap 11.

A tampon which will conform and gradually ease the introitus open to promote removal comfort should have a packing factor which will allow some conformation by the corpus to the introital opening, but not be loose enough to permit the corpus to shift to the rearmost portion of the overwrap as the tampon is withdrawn. A shift to the rearmost portion of the overwrap of too much of the corpus 10 could allow an accumulation at the rear of the tampon which would require an abrupt dilation of the introitus and increased removal discomfort.

The material used as the overwrap in this invention preferably is a soft, flexible, vaginal fluid permeable non-woven material having small apertures therethrough and a wet tensile strength in the machine direction of at least 250 grams per inch. A biodegradable material is desirable for the overwrap because it will enhance the destructability of disposed tampons. Two nonwoven fabrics which have functioned well as the overwrap and are believed to be biodegradable are: Dexter X-2172, a nonwoven fabric consisting of approximately a 60:40 cotton:rayon blend, saturation bonded with a mixture of HA8 and HA 24, Rohm & Haas acrylic binders, said fabric having a measured weight of about 0.6 to 0.7 ounce per square yard and being hydrophobic and available from C. H. Dexter & Sons Co., Windsor Locks, Conn., and Viskon, a 100% rayon, nonwoven, line-bonded material, which is hydrophilic, has a measured weight of about 0.47 ounce per square yard, and is available from Chicopee Mills, 1450 Broadway, New York, N.Y. Reemay, a hydrophobic, spunbonded, low basis weight, polyester nonwoven fabric having a measured weight of about 0.4 ounce per square yard and available from E. I. DuPont de Nemours, Wilmington, Del., is another nonwoven which has performed satisfactorily as an overwrap for tampons of this invention. Use of a highly hydrophobic material as the overwrap with a highly absorptive absorbent body can be advantageous in that it insulates the vaginal wall from collected menses and thus maintains, during menstruation, the slightly acidic condition of the vagina which exists during non-menstrual times.

The above nonwoven fabrics have no noticeable apertures therein, but some materials having noticeable apertures have been used satisfactorily. The purpose of keeping the apertures small is to prevent small pieces of corpus 10 from escaping through the overwrap 11, and to prevent edges or corners of larger pieces from projecting through the overwrap. The nominal and potential apertures, i.e., opened areas or areas encompassed by adjacent fibers in the overwrap should not exceed a size which will prevent corpus 10 from escaping from the overwrap or from protruding therethrough such as to interfere with the ejection force of the tampon from a tubular inserter. some foam-like materials, e.g., polyurethane, have a high coefficient of friction with inserter materials like polyethylene or paperboard. The static coefficient of friction of polyurethane with polyethylene is about 1.05. Therefore, the nominal and potential apertures within the overwrap should be no greater than the smallest pieces of corpus 10. The potential apertures can be much larger than the nominal apertures when the crossover points within the overwrap are not bonded. It has been found that a woven overwrap having an interfiber distance of about one-eighth inch in both directions and having no attachment at the crossover points is not acceptable in that the ejection force from a telescoping tubular inserter for that tampon is increased. It has been found that overwraps having apertures with diameters as large as one-sixteenth inch, when the tampon corpus 10 is an aggregate of foam pieces of sizes from about one-sixteenth to about three-eighths inch, do not prove detrimental to the functioning of the tampon.

It is believed desirable to maintain the exterior surface of the tampon 15 as smooth and having as low a coefficient of friction as possible for at least two reasons: to achieve a low ejection force, i.e., the force required to eject the tampon from a tubular inserter, and to prevent scraping of the soft, tender tissue within the vagina during insertion, wearing, and removal. In general, the resilient foam corpus has a higher coefficient of friction than the overwrap material and, therefore, any protrusion through the overwrap would result in an increase in the ejection force and the scraping of the tissue within the vagina.

The overwrap should have a static coefficient of friction with the interior of the inserter of less than about 0.40, and preferably less than about 0.37, to provide acceptable ejection forces with larger tampons of this invention. Overwraps having a coefficient substantially higher than 0.40 result in ejection forces which are substantially higher and prove to be objectionable by users.

The overwrap 11 should have strength characteristics so as to prevent the nonwoven material from rupturing during removal or from vaginal pressures while in vivo. The overwrap should have a wet tensile strength in the machine direction of at least about 250 grams per inch. The minimum wet internal tearing resistance as measured by TAPPI Standart T 414 ts-65 in the machine direction for the overwrap should be about 100 grams to tear 16 plies 2 inches to prevent the overwrap from tearing during removal of the tampon from the vagina.

A material which has worked well as a withdrawal string 14 is a waterproofed cotton string having a 5/3 ply and a 9 pound tensile strength. Such a string is available from Bibb Manufacturing Company, Macon, Ga., under the name of 5/3 ply Sno-Spun bleach 108 cotton.

Any string sufficiently strong to withstand removal forces can be used as the withdrawal string 14. The polyester strings generally have a higher tensile strength and can be used if a stronger string is desired. Polyester strings are available from UniRoyal Fiber & Textile, Division UniRoyal, Incorporated, 350 Columbia Road, Winnsboro, S.C. 29180.

Referring once more to FIGS. 1 and 2, overwrap 11 has applied to its surface a therapeutically active medicament composition 12 comprising an agent for control of vaginal area disorders, and the vaginal fluid soluble binding lubricant having a melting point of from about 38.degree. to about 50.degree. C.

The term "agent for control of vaginal area disorders" is intended to include any of the wide variety of therapeutic agents which are suitable as topical treatments for vaginal area disorders. A complete and thorough survey of suitable agents can be found in Benign Diseases of the Vulva and Vagina by Gardner, et al. (1968), incorporated herein by reference. Naturally, the choice of agent is not critical to the present invention and depends principally upon the nature of the disorder and the severity of affliction. In general, suitable agents are antibiotic, antiseptic, and/or anesthetic.

The following table is intended to exemplify various suitable agents for control of the three principal forms of vaginitis.

TABLE I ______________________________________ Agents for Control of Vaginitis Form of Vaginitis Controlling Agent ______________________________________ (1) Candidiasis Gentian violet Nystatin Candicidin Chlordantoin Amphotericin B Propionic acid and salts Corticosteroids Hydrocortisone Fluocinolone acetonide Flurandrenolone (2) Trichomoniasis Metronidazole Polymyxin B Acetarsone Furazolidone Diiodohydroxyquin (3) Haemophilus Oxytetracycline vaginalis vaginitis Sulfonamides Sulfisoxazole Sulfadiazine Nitrofurazone ______________________________________

For purposes of the present invention, the selected therapeutic agent is adhered to the tampon overwrap 11 by dissolving or suspending the agent in a binding lubricant, which is in turn applied to the tampon overwrap. The medicament compositions may be applied to the overwrap by any of a wide variety of techniques such as dipping, impregnating, spraying, or painting.

In a preferred embodiment, the medicament composition is applied to a portion of the overwrap surface, thereby assuring that the absorptive properties of the tampon are not hindered and that the tampon will perform adequately when worn during menstruation. Although longitudinal stripes of medicament, see FIGS. 1 and 2, are suitable, it is clear that the medicament may be applied to the tampon in essentially any geometric pattern which will leave a portion of the overwrap uncoated to assure adequate absorption for menstrual use. In general, it has been found suitable to apply medicament to no more than 50% of the overwrap surface area.

As used herein, the term "binding lubricant" is intended to include various select surface active waxes, uniquely characterized temperature a high solubility in the physiological fluids of the vagina and a melting point slightly above the normal body temeprature of the vagina.

It has been discovered that proper selection of the binding lubricant is critical to optimum delivery of the therapeutic agent to the afflicted vagina area. Although not wishing the be bound by theory, it is believed that by selecting a binding lubricant which solubilizes in vaginal fluid, it is possible to effect, in essence, a sustained-release of the active agent. In other words, the therapeutic agent, being intimately associated with the binding lubricant, is released from the tampon overwrap 11 in a relatively continuous flow as the binding lubricant is solubilized in the vagina. In order to achieve a sustained-release of active, the binding lubricant should have a solubility in vaginal fluid of from about 0.5 grams of binding lubricant per cubic centimeter of vaginal fluid (hereinafter expressed as gm/cc) to about 10 gm/cc, preferably about 1 gm/cc. As previously noted, vaginal fluid is an aqueous solution, thus vaginal fluid is analogous to isotonic saline in solubilization properties. It is therefore acceptable to assume that solubility of the binding lubricant in isotonic saline, within the desired range, is a suitable measure of solubility in vaginal fluid, within the desired range.

In addition to solubility characteristics, suitable binding lubricants should have a melting point slightly above normal body temperature in the vagina. As previously noted, non-menstrual use of the instant medicated tampon, which is essential to efficacious treatment of vaginal disorders, emphasizes the importance of comfortable insertion of the tampon. Suitable binding lubricants when warmed to body temperture exist in an amorphous state between solid and liquid which enables the binding lubricant to adhere to the tampon overwrap, yet lubricate vaginal surfaces.

Thus, the medicated tampon of the present invention can be comfortably inserted during non-menstrual periods to achieve continuous treatment of the disorder. As is well known, normal body temperature in the vagina is 37.degree.C. Accordingly, suitable binding lubricants should have a melting point of from about 38.degree. to about 50.degree.C, preferably 42.degree. to 45.degree.C.

Preferred binding lubricants are innocuous, inert, nonvolatile materials having a pH in dilute solution near normal non-menstrual vaginal pH. Vaginal pH generally varies within the range of 3.8 to 4.2. Accordingly, preferred binding lubricants have a pH in dilute solution of from about 3.5 to about 7.0, preferably about 4.0.

Preferred binding lubricants include, for example, the following surface active waxes: polyethylene glycol having an average molecular weight of 1,540; polyethylene glycol having an average molecular weight of 4,000; polyethylene glycol having an average molecular weight of 6,000; polyethylene-4-sorbitan monostearate; polyoxyl 40 stearate; mixtures thereof; and mixtures thereof with polyethylene glycol having an average molecular weight of 1,000. Suitable mixtures include, for example, 75 percent by weight polyethylene glycol having an average molecular weight of 1,000 and 25 percent by weight polyethylene glycol having an average molecular weight of 4,000; and 70 percent by weight polyethylene glycol having an average molecular weight of 1,540 and 30 percent by weight polyethylene glycol having an average molecular weight of 6,000. Polyethylene glycol having an average molecular weight of 1,540 is an especially preferred binding lubricant.

Efficacious concentrations of the agent in the medicament composition will vary depending upon such considerations as the disorder being treated, the severity of affliction, and the potency of the agent. Accordingly, the concentrations of constituents in suitable medicament compositions cannot be predicted on other than an individual basis. However, one skilled in the art will readily perceive suitable medicament composition formulations for individual circumstances. Thus, the concentration of agent in the medicant compositions herein is left to routing evaluation and determination. As a general guideline, the medicant compositions suitable for use in the present invention comprise from about 0.1 percent to about 10.0 percent by weight of the therapeutic agent, and from about 90.0 percent to about 99.9 percent by weight of the binding lubricant.

The tampon of this invention can be inserted into a vagina via a telescoping tube type inserter, as is well known to those of ordinary skill in the tampon art. One such inserter having inwardly tapering flexible segments at the leading end to form a normally closed, smooth, openable, leading end is shown in FIG. 1 with the tampon 15 of FIG. 2 held therein. The inserter used with the tampon of this invention was molded from polyethylene, but can also be made of other materials well known to men of ordinary skill in the tampon inserter art. The tampon 15 is resiliently compacted and maintained in that condition before and during insertion by placing it in the tubular inserter 17. Resiliently compacted as used herein means compressed to a degree such that the absorptive body takes on a readily releasable temporal set, i.e., a set which dissipates in the absence of fluids after the tampon is ejected from a constraining means such as an inserter. The overwrap 11 of the tampon 15 is in contact with the inner surface of the inserter 17. An ejecting means, such as the ejector 18, removes a tampon from the inserter. In the embodiment of FIG. 1, ejector 18 pushes against the rear end of tampon 15 to move it forward in the inserter, open the closure at the forward end of the inserter and expel the tampon from the inserter 17.

The tampon, used in the inserter, forces open the segments at the forward end of the inserter. The inserter 17 is inserted into the vagina and the tampon 15 is ejected from the outer tube by pushing the ejector 18 so that it telescopes within the inserter 17. The inserter 17, with the ejector 18 therein, is removed from the vagina after the tampon 15 has been fully ejected from inserter 17 and deposited within the vagina.

The following example is intended to illustrate a suitable, preferred embodiment of the invention concept; and is not intended to limit the scope of the invention herein.

EXAMPLES

MEDICATED CATAMENIAL TAMPON

A medicament composition was prepared by agitating 2.30 grams of nystatin of potency 5007 units per milligram of "as is" nondried powder having a moisture content of 3.9 percent, a therapeutic agent for control of vaginal area disorders, and 50.0 grams of polyethylene glycol having an average molecular weight of 1,540 in a Waring Blender. The resulting composition was applied, in four equidistant longitudinal stripes one-fourth inch in width, to the overwrap of a resilient foam catamenial tampon comprising an aggregate of individual pieces of absorbent foam material, said aggregate being encased within the flexible fluid permeable overwrap. The foam material, described hereinbefore as Foam I, was characterized by a dry modulus of compression at 25 percent compression in the range of 0.2 to about 2.0 pounds per square inch. The tampon overwrap consisting of a hydrophobic nonwoven polyester fabric having a wet tensile strength in the machine direction of about 250 grams per inch.

The resulting medicated catamenial tampon is used in treating vaginal area disorders during both the menstrual and non-menstrual periods of the female cycle with good results.

The following binding lubricants are substituted for polyethylene glycol having an average molecular weight of 1,540 in the above-described medicament composition and substantially equivalent results are achieved: polyethylene glycol having an average molecular weight of 4,000; polyethylene glycol having an average molecular weight of 6,000; polyethylene-4-sorbitan stearate; polyoxyl 40 stearate; a mixture of 70 percent by weight of polyethylene glycol having an average molecular weight of 1,540 and 25 percent by weight of polyethylene glycol having an average molecular weight of 4,000; a mixture of 70 percent by weight of polyethylene glycol having an average molecular weight of 1,540 and 30 percent by weight of polyethylene glycol having an average molecular weight of 6,000; a mixture of 10 percent by weight of polyethylene-4-sorbitan monostearate, 15 percent by weight of polyoxyl 40 stearate, and 75 percent by weight of polyethylene glycol having an average molecular weight of 1,540; a mixture of 70 percent by weight of polyethylene glycol having an average molecular weight of 1,000 and 30 percent by weight of polyethylene glycol having an average molecular weight of 6,000; and the like.

The following therapeutic agents for control of vaginal disorders are substituted for nystatin in the abovedescribed medicament composition with comparable results: gentian violet; candicidin; chlordantoin; amphotericin B; propionic acid and salts; corticosteroids such as hydrocortisone, fluocinolone acetonide, and flurandrenolone; metronidazole, polymyxin B; acetarsone; furazolidone; diiodohydroxyquin; oxytetracycline; sulfonamides such as sulfisoxazole and sulfadiazine; and nitrofurazone.

The overwrap of the above described tampon is replaced by overwraps consisting of Dexter X-2172 and Viskon, respectively, with substantially equivalent results. The foam employed in this example is replaced with Foam II and Foam III, respectively, with similar results.

Claims

What is claimed is:

1. A medicated catamenial tampon, comprising: a resilient mensesphilic polyurethane foam corpus having a dry modulus of compressibility of from about 0.2 lbs. per. sq. in. to about 0.6 lbs. per sq. in., a wet modulus of compressibility of from 0.1 psi to about 0.3 psi, a shape modulus of compression of from about 0.05 lbs. to about 1.0 lbs., and a critical surface tension of at least 60 dynes per centimeter; and a medicamentbearing hydrophobic non-woven overwrap which is permeable to vaginal fluids, wherein said medicament comprises a safe and effective amount of a therapeutically active agent for control of vaginal disorders and a vaginal fluid-soluble binding lubricant having a melting point within the range of from 42.degree. to about 45.degree.C.

2. A medicated tampon according to claim 1 wherein said overwrap comprises a hydrophobic non-woven tissue having a wet tensile strength in the machine direction of at least 250 grams per inch.

3. A medicated tampon according to claim 1 wherein said therapeutically active agent is nystatin.

4. A medicated tampon according to claim 1 wherein said binding lubricant is selected from the group consisting of polyethylene glycol having an average molecular weight of 1,540, polyethylene glycol having an average molecular weight of 4,000, polyethylene glycol having an average molecular weight of 6,000, polyethylene-4-sorbitan monostearate, polyoxyl 40 stearate, mixtures thereof, and mixtures thereof with polyethylene glycol having an average molecular weight of 1,000.

5. A medicated tampon according to claim 4 wherein said binding lubricant is polyethylene glycol having an average molecular weight of 1,540.