Evaluation of in vitro drug release, pH change, and molecular weight degradation of poly(L-lactic acid) and poly(D, L-lactide-co-glycolide) fibers

Biodegradable fibers of poly( (L)- lactic acid) ( PLLA) and poly( (D), (L)- lactide- co- glycolide) ( PLGA) that encapsulated a water- soluble drug were created by a patented technique consisting of wet- spinning a water- in- oil emulsion. These fibers are 2.4% by mass drug, which is slowly released, making these fibers potential candidates for implantation as drug delivery devices and/ or tissue- engineering substrates. Drug release kinetics and changes in molecular weight were investigated over time. This study demonstrated that drug release rates and molecular weight degradation are a function of the amount of aqueous phase added as an emulsion during fabrication. The type of polymer used ( PLLA or PLGA) determines the molecular weight degradation rates, but has little effect on drug release kinetics.