SYNTHESIS AND SURFACE CHARACTERIZATION OF FUNCTIONALIZED POLYLACTIDE COPOLYMER MICROPARTICLES

Microparticles of poly(lactide) (PLac) and its copolymers with the ami no acids, serine (P(Lac-Ser)), and aspartic acid (P(Lac-Asp)), respect ively, were synthesized using the solvent evaporation microemulsion te chnique. Poly(vinyl alcohol) (PVA) was added as a non-ionic surfactant to stabilize the particles. The particle sizes are in the range of 20 0 nm. The surface of the particles was characterized by FTIR transmiss ion spectroscopy under evacuation at room temperature and at 200 degre es C. Hydroxy groups originating from PVA exist on the surfaces of the particles and they were observed at 3506 cm(-1). Free hydroxy groups originating from the serine residue pendant to the copolymer P(Lac-Ser ) backbone were observed at 3396 cm(-1). Also, free carboxylic acid gr oups pendant to the copolymer P(Lac-Asp) backbone, originating from th e aspartic acid residue, were observed at 3387 cm(-1). The appearance of the free hydroxy or carboxylic acid groups in the IR spectra also s howed that these hydrophilic functional groups moved to the surface of the particles in the process of microemulsion. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.