STABILITY STUDY OF NANOPARTICLES OF POLY(EPSILON-CAPROLACTONE), POLY(D,L-LACTIDE) AND POLY(D,L-LACTIDE-CO-GLYCOLIDE)

The objective was to evaluate the stability of nanoparticles prepared with poly(epsilon-caprolactone), poly(D,L-lactide) and poly(D,L-lactid e-co-glycolide) polymers and stored at different temperatures and in d ifferent media. The stability parameters studied were molecular weight and crystallinity of the polymer, nanoparticle size and pH. The resul ts show that the stability of polymeric nanoparticles depends on (i) t he type of polymers with the following increasing order of polymer sta bility: PLA25GA50 < PLA37.5GA25 < PLA50 = PCL, (ii) the storage temper ature: PCL and PLA50 nanoparticles can be kept at 4 degrees C and RT d uring one year, while PLA37.5GA25 and PLA25GA50 nanoparticles have to be stored at 4 degrees C, and (iii) the storage conditions: buffering or freeze-drying nanoparticles improves stability. (C) 1996 Elsevier S cience Limited