PREPARATION, SWELLING CHARACTERISTICS AND EVALUATION OF HYDROGELS FORSTOMACH SPECIFIC DRUG-DELIVERY

The development of pH sensitive, biocompatible and biodegradable hydro gels as novel drug delivery systems was carried out to achieve localiz ed drug delivery. Poly[N-vinyl pyrrolidone-acrylic acid]-polyethylene glycol (Poly[NVP-AA]-PEG) interpolymer type systems were prepared by f ree radical polymerization. Azobisisobutyronitrile (AIBN) was used for initiating the polymerization and N,N '' methylene bisacrylamide was employed as a crosslinking agent. The concentration of initiator and c rosslinking agent were varied and the reaction parameters were optimiz ed. The obtained poly[NVP-AA]-PEG hydrogels were fully characterized b y fourier transform infrared spectroscopy (FT-IR), differential scanni ng calorimetry (DSC): thermogravimetric analysis (TGA) and optical mic roscopy (OPM). The equilibrium swelling studies were carried out in si mulated gastric fluid (SGF) of pH 1.2 and simulated intestinal fluid ( SIF) of pH 6.8. The gels were swollen extensively in SIF when compared 13 SGF. The influence of pH on the swelling of the hydrogel was also studied in buffers of varying pH. 5-Fluorouracil (5-FU) was loaded and the in vitro release studies were carried out in SGF. The results of: his study suggest that poly [NVP-AA]-PEG hydrogels could be useful for localized delivery of drugs in the stomach. (C) 1997 Elsevier Science B.V.