CHITOSAN/MONTMORILLONITE COMPOSITES AS MATRICESFOR PROLONGED DELIVERY OF SOME NOVEL NITRIC OXIDE DONORCOMPOUNDS BASED ON THEOPHYLLINE AND PARACETAMOL

摘要

Chitosan-montmorillonite nanocomposite hydrogels were prepared by crosslinking chitosan nanocomposites with glutaraldehyde. The following types of clays have been used: Cloisite 15A, Cloisite 93A, Dellite HPS and Dellite 67G. The swelling behaviour of the crosslinked hydrogels containing nanoparticles was followed in acidic media with pH = 2.2. These hydrogels have been loaded with paracetamol, theophylline, two xanthine derivatives 7-[2-hydroxy-3-(4-acethyl-amino-phenoxy)-propyl]-8-R-1,3-dimethyl-xanthine derivatives (with R=H and NO2 for D1 and respectively D2) and two corresponding new nitric oxide donors (NO-donors) as 7-[2-nitroxyacethyl-oxy-3-(4-acethyl-amino-phenoxy)-propyl]-8-R-l,3-dimethyl-xanthine compounds (R=H, NO2 for 65 and respectively 77 compounds), their controlled release being also evaluated in an acidic solution (pH = 2.2) simulating gastric fluid. The swelling and release kinetics was studied. It has been established that almost all releases involve a non-Fickian or an anomalous transport mechanism.