Absorbable Coatings: Structure and Drug Elution

Abstract

Drug delivery from biodegradable polymer coatings is becoming an important area of research for applications including medical devices. In this work, we probe the impact of polymer chemistry and solvent evaporation rate on drug morphology and the subsequent elution from biodegradable polymer systems. Two different formulations of poly(lactic-glycolic-acid) (PLGA) polymers are used in combination with tetracycline (TC) to fabricate coatings using two different solvent evaporation rates. We have conducted elution studies to quantify the release behavior of tetracycline (TC) at the first 2-3 days of dissolution. Significantly we have correlated the drug release kinetics with the drug microstructure of TC/PLGA coating using atomic force microscopy (AFM) and laser scanning confocal microscopy (LSCM). These results suggest that polymer chemistry affects the rate of water absorption and drug dissolution which in turn alters the rate of TC release during the early stages of drug elution.