Keratin-Based Powders and Hydrogel for Pharmaceutical Applications

Abstract

A hydratable, highly absorbent keratin solid fiber or powder capable of absorbing a large weight excess of water may be produced by partially oxidizing hair keratin disulfide bonds to sulfonic acid residues and reacting the sulfonic acid residues with a cation. The neutralized suspension can be filtered, washed, and dried, leaving keratin solid which can be shredded into fibers and further ground into powder. Addition of water to the solid produces a hydrogel. The powder or hydrogel may be useful as an absorbent material, as a therapeutic for skin, or as an excipient. The keratin materials can be incorporated into nonwoven films. The hydrogel can be used as a biocompatible viscoelastic filler for implant applications. Another use for the absorbent keratin and keratin hydrogel is as an excipient in pharmaceutical and cosmetic applications.

Description

RELATED APPLICATIONS [0001] The present application is a continuation of U.S. Ser. No. 10 / 409,018, filed Apr. 8, 2003, which is a divisional of U.S. patent application Ser. No. 09 / 638,643 filed Aug. 13, 2000, now U.S. Pat. No. 6,544,548, which is a continuation-in-part of U.S. patent application Ser. No. 09 / 587,157 filed Jun. 5, 2000, which is a continuation-in-part of U.S. patent application Ser. No. 09 / 528,893 filed Mar. 20, 2000, which is a continuation-in-part of U.S. patent application Ser. No. 09 / 512,918, filed Feb. 25, 2000 which is a continuation-in-part of U.S. patent application Ser. No. 09 / 394,782 filed on Sep. 13, 1999. All of the listed patents and applications are incorporated into this application in their entirety by reference for all purposes.FIELD OF THE INVENTION [0002] The present invention is related generally to a keratin composition and method for making same. Specifically, the present invention relates to an absorbent keratin powder or fiber. More specificall...

AI Technical Summary

Benefits of technology

[0011] The resulting solid may then be suspended in a non-aqueous solvent and the pH may be adjusted upward with base—conveniently to at least neutral pH. Preferred solvents for this second solution do not include more than about 20 volume percent water, as the water may hydrolyze the peptide backbone during processing. Preferred solvents would include alcohols such as methanol, ethanol, or propanol, for example, and would also include non-aqueous polar, water-miscible solvents such as acetone and tetrahydrofuran, for example. An effective solvent should be able to solvate a Lewis base and should also be able to provide a medium able to keep the keratin sufficiently swelled to allow ionic associations or interactions between the base cations and anionic sulfonic acid groups in the keratin. Small amounts of water will assist in this regard, so blends of the aforementioned solvents in combination with water up to 20 volume percent may be used. Preferred bases include, but are not limited to sodium hydroxide, potassium hydroxide and ammonium hydroxide, which, as is known in the art, would yield or produce sodium, potassium and ammonium cations, respectively, upon entering solution.

[0050] Keratin excipient preparations may also include other compounds such as diluents, fillers, lubricants, stabilizers, binders and gelants. Diluents and fillers are added to increase bulk formation, and lubricants to reduce friction during the tableting or other formulation process. Binders are used in tableting and provide the cohesiveness necessary for bonding together the ingredients under compression. They also increase the strength of the compressed tablet and decrease its friability, leading to an improvement in the both appearance and mechanical characteristics.

Problems solved by technology

In the case of chemically treated absorbent materials and films, depending on the chemicals, the leachate may be irritating and is not believed to be beneficial.

Skin contact with urine can also occur and result in irritation.

This type of irritation may exacerbate diaper rash problems.