The influence of temperature on the degradation rate of LactoSorb copolymer.

Heat is one of the fundamental forces that influence the rates of chemical reactions. The hydrolysis of an absorbable polymer is a function of many factors, both material-related and implant-site-related, including temperature. There is variance in temperature among patients as well as among various animals in which degradation studies are performed. This study investigated the influence of temperature on hydrolysis and found that a variance from 37 degrees C to as little as 2 degrees C can affect the rate of hydrolysis of a PGA/PLLA copolymer about 25-30%, with the rate increasing with increasing temperature. As most animals of biomedical interest have a body temperature on the order of 1-3 degrees C greater than that of humans, it is possible that animal testing may be "worst case"; that is, strength loss may be accelerated in animals relative to that in human patients. Also, variation of body temperature within the human population may contribute to some variance in the rate of hydrolysis from person to person; however, other influences may minimize this effect and make it difficult to observe clinically.