Preparation and in vitro evaluation of pH sensitive GMAª²dextran hydrogels

    WU Hong, ZHANG Zhenª²Xi, WU Daoª²Cheng, REN Bo, SU Dan, ZHANG Kun

    1Ministry of Education Key Laboratory of Biomedical Information Engineering, School of Life Science & Technology, Xi¬ðan Jiaotong University, Xi¬ðan 710049, China, 2Department of Chemistry, School of Pharmacy, Fourth Military Medical University, Xi¬ðan 710033, China, 3Department of Anesthesiology, PLA 302 Hospital, Beijing 100039, China

    ¡¾Abstract¡¿ AIM: To prepare the biodegradable pHª²sensitive hydrogels for controlled drug delivery and to study its intelligent drugª²release characteristics. METHODS: Hydrogels were obtained by radical copolymerization of aqueous solution of glycidyl methacrylate derivatived dextran (GMAª²dex) with acrylic acid (AAc) using ammonium peroxydisulfate (APS) and N,N,N,Nª²tetramethylethylenediamine (TEMED) as an initiation system. The degree of GMA substitution (DS) was determined by 1Hª²NMR. The hydrogels were subjected to equilibrium swelling studies in enzymeª²free simulated gastric and intestinal fluids (SGF and SIF). The release profiles of Pingyangmycin (PYM)ª²entrapped hydrogels in vitro were established in enzymeª²free SGF and SIF. RESULTS: The DS of GMA was 10.5 and the swelling studies clearly indicated that these hydrogels were more swollen in SIF than those in SGF. The release of PYM from the hydrogels was much faster in SIF. After 24 h, about 22% and 43% of the entrapped drug were released in SGF and SIF, respectively. CONCLUSION: The swelling and drug release of Poly (GMAª²dex/AAc) hydrogels are strongly dependent on the pH value. ......