CONTROLLED DELIVERY OF THERAPEUTICS FROM MICROPOROUS MEMBRANES .1. FABRICATION AND CHARACTERIZATION OF MICROPOROUS POLYURETHANE MEMBRANES CONTAINING POLYMERIC MICROSPHERES

This paper describes a process for the inclusion of polymer microspher es in microporous polyurethane tubes and membranes. These composites w ere fabricated via a spray, phase-inversion technique using Cardiothan e(TM) 51, a medical grade polyurethane, and either spray-dried poly(D, L-lactide-co-glycolide 50:50) microspheres or commercially available f luorescent polystyrene-latex microspheres. Characterization of the pol yurethane membranes was performed using Fourier-transform infrared spe ctroscopy, differential scanning calorimetry, dynamic mechanical analy sis, hydraulic permeability testing, scanning electron microscopy, and visible and fluorescence light microscopy. The results indicated the feasibility of layering microspheres throughout the microporous membra ne or wall of the microporous tube, and the potential of such composit e structures for local delivery of bioactive substances. (C) 1997 Else vier Science Limited.