Compliant dehydrated tissue for implantation and process of making the same

A process for preparing a pliable soft tissue specimen, comprising the steps of:

• (1) treating natural soft tissue obtained from a donor with:
• (a) liquid compositions of gradually increasing concentrations of a polar organic solvent or solvents, until the last of said liquid compositions contains at least approximately 25% by volume of said solvent, or mixture of solvents, the balance being water, the solvent being selected from a group consisting of aliphatic alcohols having 1 to 3 carbons and other water miscible polar organic solvents;
• (b) thereafter with a second liquid composition of aqueous glycerol or of low molecular weight polyethylene glycol having a molecular weight less than approximately 1000 D, the glycerol or the low molecular weight polyethylene glycol, or mixtures thereof being in a concentration range of approximately 10 to 50% by volume, said second liquid composition also containing approximately 3-20% weight by volume of polyethylene glycol of a molecular weight in the range of 6,000 D to 15,000 D and approximately 2 to 75 units per milliliter heparin of a molecular weight greater than approximately 3 KD;
• (2) thereafter briefly immersing the soft tissue in an aqueous heparin solution, and
• (3) thereafter freezing the tissue and lyophilizing the tissue to dryness.