親水性セグメント化ポリウレタンウレアからの抗菌剤徐放挙動

Abstract

Blood-compatible segmented polyurethaneureas were evaluated as drug delivery matrices using crystal violet (CV), benzethonium chloride (AC) and acrinol (AC) as model drugs. The polymers were synthesized from ABA-type triblock copolyethers as prepolymers, where A stands for poly (oxyethylene) and B for poly (oxytetramethylene). Microphase separation was observed in the polyurethaneureas, including drug-doped ones. CV dissolved more in the hard segment domains than in the soft segment matrix, whereas BC easily dissolved in the soft segment matrix. AC dissolved in both phases. The drug release behaviors from these polymer films were analysed by the exponent relation Mt/M∞=ktn, where k and n are constants and Mt/M∞ is the fraction of drug released until time, t. The constant k increased with poly (oxyethylene) content, i.e. with the increase of swelling in water. The constant n was found to be ca. 0.5 in many samples, which suggests that the release of drugs from these polymers is explained by the Fickian diffusion model. However, the mechanism became non-Fickian with the increase of swelling of the devices in CV and BC systems. This observation seems to be due to the heterogeneous dissolution of drug in the microphase separated structure.