DIFFERENT MOLECULAR-WEIGHT CHITOSAN MICROSPHERES - INFLUENCE ON DRUG LOADING AND DRUG-RELEASE

Influence of chitosan molecular weight on drug loading and drug releas e of drug-loaded chitosan microspheres was studied. Chitosans of 70,00 0 (LC), 750,000 (MC), and 2, 000, 000 (HC) molecular weight were emplo yed alone or as mixtures (HC/LC 1:1-1:2 w/w). Ketoprofen (ket) was cho sen as the model drug to be encapsulated. Microspheres characterized b y different theoretical polymer/drug ratios were prepared (2:1, 1:1, 1 :2 w/w). Satisfactory ket contents were obtained for all batches of ch itosan microspheres with the theoretical polymer/drug ratio 1:2 w/ w; microspheres made of HC/LC (1:2 w/w) were characterized by good drug c ontent and encapsulation efficiency independent by polymer/drug ratio. Prepared chitosan microparticulate delivery systems can modulate ket release within 48 hr. Microspheres consisting of HC/LC (1:2 w/w) were the most suitable formulation in controlling drug release.