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.

1 .- 94 . (canceled)  
     
     
         95 . A process for the preparation of a preparation comprising an active agent bound to a keratin excipient, wherein said active agent is ionically associated with said sulfonate group, comprising the steps: 
 (a) oxidizing keratin in a first solution comprising a soluble oxidizing agent, such that a portion of the disulfide bonds of said keratin are oxidized to form sulfonic acid residues to obtain an oxidized solid fraction;    (b) separating said oxidized solid fraction from said first solution; contacting said oxidized solid fraction with a second solution comprising a cationic form of an active agent dissolved in a solvent;    (c) maintaining said second solution containing said oxidized solid fraction and said active agent for a time and at a temperature effective to cause an ionic interaction between said sulfonic acid residues and said cationic form of said active agent; and    (d) substantially removing the solvent from said salt solution to obtain a solid preparation.    
     
     
         96 . The process of  claim 95 , further comprising grinding said solid preparation to form a powder.  
     
     
         97 . The process of  claim 95 , wherein said active agent is a pharmaceutical agent or a cosmetic agent capable of forming a cation  
     
     
         98 . The process of  claim 95 , wherein said keratin is obtained from hair, fur, nails, feet, beaks, feathers, horns or hooves.  
     
     
         99 . The process of  claim 95 , wherein said keratin is obtained from hair.  
     
     
         100 . The process of  claim 99 , wherein said hair is human hair.  
     
     
         101 . A preparation made by the process of  claim 95 .  
     
     
         102 . A process for the preparation of a hydratable keratin excipient comprising the steps: 
 (a) oxidizing keratin in a first solution comprising a soluble oxidizing agent, such that a portion of the disulfide bonds of said keratin are oxidized to form sulfonic acid residues to obtain an oxidized solid fraction;    (b) separating said oxidized solid fraction from said first solution; contacting said oxidized solid fraction with a second solution comprising monovalent cations dissolved in a solvent;    (c) maintaining said second solution containing said oxidized solid fraction and said monovalent cations for a time and at a temperature effective to cause an interaction between said sulfonic acid residues and said monovalent cations to obtain a salt solution of said keratin and said monovalent cations; and    (d) substantially removing the solvent from said salt solution to obtain a hydratable keratin solid.    
     
     
         103 . The process of  claim 102 , further comprising grinding said hydratable keratin solid to form a powder.  
     
     
         104 . The process of  claim 102 , further comprising contacting said hydratable keratin with an aqueous solution to form a hydrogel.  
     
     
         105 . The process of  claim 104 , further comprising adding an active agent to said aqueous solution before contacting said hydratable keratin to form said hydrogel.  
     
     
         106 . The process of  claim 104 , further comprising admixing an active agent with said hydratable keratin solid.  
     
     
         107 . The process of  claim 106 , further comprising contacting said admixture of said hydratable keratin and said active agent with an aqueous solution to form a hydrogel.  
     
     
         108 . The process of  claim 104 , wherein said keratin is obtained from hair, fur, nails, feet, beaks, feathers, horns or hooves.  
     
     
         109 . The process of  claim 104 , wherein said keratin is obtained from hair.  
     
     
         110 . The process of  claim 109 , wherein said hair is human hair.  
     
     
         111 . A preparation made by the process of  claim 105 .  
     
     
         112 . A preparation made by the process of  claim 106 .  
     
     
         113 . A process for the preparation of a preparation comprising a cross-linked insoluble oxidized keratin excipient comprising the steps: 
 (a) oxidizing keratin in a first solution comprising a soluble oxidizing agent, such that a portion of the disulfide bonds of said keratin are oxidized to form sulfonic acid residues to obtain an oxidized cross-linked insoluble solid fraction;    (b) separating said oxidized cross-linked insoluble solid fraction from said first solution; and    (c) substantially removing the solvent from said oxidized cross-linked insoluble solid fraction.    
     
     
         114 . The process of  claim 113 , further comprising grinding said oxidized cross-linked insoluble solid fraction to form a powder.  
     
     
         115 . The process of  claim 113 , wherein said keratin is obtained from hair, fur, nails, feet, beaks, feathers, horns or hooves.  
     
     
         116 . The process of  claim 113 , wherein said keratin is obtained from hair.  
     
     
         117 . The process of  claim 116 , wherein said hair is human hair.  
     
     
         118 . A preparation made by the process of  claim 113 .  
     
     
         119 . A liposome preparation comprising a keratin excipient associated with an active agent, wherein said keratin is chemically modified to contain sulfonate groups.  
     
     
         120 . The preparation of  claim 119 , wherein said keratin is derived from hair, fur, nails, feet, beaks, feathers, horns or hooves.  
     
     
         121 . The preparation of  claim 119 , wherein said keratin is derived from hair.  
     
     
         122 . The preparation of  claim 121 , wherein said hair is human hair.  
     
     
         123 . The preparation of  claim 119 , wherein said sulfonate groups are ionically associated with cations.  
     
     
         124 . The preparation of  claim 123 , wherein said cations comprise the cationic form of an active agent.  
     
     
         125 . The preparation of  claim 123  wherein said cations comprise monovalent cations.  
     
     
         126 . The preparation of  claim 125 , wherein said monovalent cations comprise sodium or potassium.  
     
     
         127 . The preparation of  claim 119 , wherein said active agent is the free base of an active agent that may be otherwise formulated as a hydrochloride.  
     
     
         128 . The preparation of  claim 119 , wherein said active agent is a pharmaceutical agent  
     
     
         129 . The preparation of  claim 128 , wherein said pharmaceutical agent is a protein, polypeptide or peptide.  
     
     
         130 . The preparation of  claim 119 , wherein said active agent is a cosmetic agent.  
     
     
         131 . The preparation of  claim 130 , wherein said cosmetic ingredient is a water soluble peptide derived from keratin.  
     
     
         132 . The preparation of  claim 119 , wherein association of said active agent with said keratin excipient provides for the controlled release of said active agent.  
     
     
         133 . The preparation of  claim 119 , wherein said keratin excipient comprises a hydratable keratin.  
     
     
         134 . The preparation of  claim 119 , wherein said keratin excipient is a keratin hydrogel.