BIODEGRADABLE COMB POLYESTERS - PART-1 - SYNTHESIS, CHARACTERIZATION AND STRUCTURAL-ANALYSIS OF POLY(LACTIDE) AND POLY(LACTIDE-CO-GLYCOLIDE) GRAFTED ONTO WATER-SOLUBLE POLY(VINYL ALCOHOL) AS BACKBONE

To overcome discontinuous or polyphasic drug release rates of parenter al delivery systems (PDSs) for peptides and proteins, typical for line ar polyesters, novel biodegradable brush-like poly(lactide) and poly(l actide-co-glycolide) (PLG) grafted onto water-soluble poly(vinyl alcoh ol) (PVA) as backbone were investigated. These polymers were synthesiz ed by ring-opening melt polymerization using stannous octoate as catal yst. The branched PVA-PLGs were characterized by 1D- and 2D-n.m.r. spe ctroscopy and other methods, such as i.r., g.p.c., d.s.c. and static l ight scattering. The incorporation of the backbone and the comb struct ure was demonstrated by H-1- and C-13-n.m.r. spectra, as well as by li ght scattering studies. The physico-chemical properties, such as molec ular composition and architecture, molecular weight, degree of crystal linity, melting point and glass transition point, could be systematica lly adjusted to the requirements of drug delivery. Therefore, this new class of biodegradable polymers has considerable potential as a PDS. (C) 1998 Elsevier Science Ltd. All rights reserved.