BIOMEDICAL APPLICATIONS OF RUBBERS AND ELASTOMERS

Headnote

ABSTRACT

This paper discusses recent topics in the biomedical applications of rubbers and elastomers. It focuses on the current problems obtaining materials for implants from manufacturers due to concern about potential liability by raw materials manufacturers. The many problems and opportunities for development of polyurethane and silicone implants are discussed along with a review of a few other rubbers and elastomers used for implants. Some of the many other rubbers and elastomers available in medical grades and used in non-implant biomedical applications are presented.

CONTENTS

I. Introduction....................500

II. Availability of Materials for Long-Term Implants ....................501

A. The DuPont Teflon - Vitek Story....................501

B. Artificial Breasts and the Dow Corning Bankruptcy....................502

C. The Biomaterials Access Assurance Act of 1998....................502

D. The Current Status of Biomaterials Availability....................503

E. So How Do You Buy Polymers for Implants?....................505

III. Other Biomedical Issues That Have Become More Significant....................508

A. Latex Allergic Reactions....................508

B. Transgenic Mice for Carcinogen Testing of New Elastomers....................508

C. Migration of Plasticizers from Biomedical Products....................508

IV. Polyurethanes....................509

A. Implant Applications of Polyurethanes....................509

B. Degradation of Polyurethanes In Vivo....................510

C. Environmental Stress Cracking of Polyurethanes....................511

D. Improved Blood and Tissue Compatibility with Polyurethanes....................512

E. Polyurethane Hybrids....................512

V. Silicone Rubbers....................513

A. Silicones for Artificial Breasts....................513

B. Historical Problems with Silicone Rubber Implants....................514

C. Other Silicone Implants....................514

D. Silicones for Non-Implant Applications....................514

VI. Other Implant Rubbers and Elastomers....................515

A. Drug Delivery Systems....................515

B. Rubber and Elastomers Non-Implant Medical Applications....................516

VII. Summary....................516

VIII. References....................516

I. INTRODUCTION

In the biomedical field, applications for the use of rubbers and elastomers can be divided into internal (in vivo) and external (in vitro) uses. Internal uses can include both short-term applications such as catheters and long-term implants. External applications include skin contact applications that are regulated such as drug infusion patches as well as a much larger number of medical related applications such as disposable gowns for surgeons and operating tables. In terms of dollar volume and pounds of materials used, external uses FAR surpass the amount of material used in implants, even including materials with temporary body contact. However, the rigorous demands of materials used in implants and the many associated regulations and standards coupled with the possible life of death nature of the implants, litigation, sterilization issues, and the sometimes difficult...