pH responsive PAIAm-g-PIPA microspheres: Preparation and drug release

✍ Scribed by Xiongwei Li; Yushu Huang; Jing Xiao; Changhong Yan

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 488 KB
• Volume: 55
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1995.070551308

✦ Synopsis

Poly(N-isopropylacrylamide) (PIPA) was synthesized by radical polymerization with 2,2'azobisisobutyronitrile (AIBN) as an initiator and 3-mercaptopropionic acid (MPA) as a chain-transfer reagent in methanol (MeOH) at 70°C for 7 h. The resultant PIPA was grafted to polyallylamine hydrochloride (PAlAm -HCl) by amide formation under the influence of water-soluble carbodiimide l-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC). The graft polymer was made into microspheres (MS) by chemical crosslinking. The pH-responsive drug release of the graft polymer microspheres was examined by releasing phenobarbital natrium (PN), which was carried on the microspheres by physical adsorption. A dynamic dialysis technique was used in the drug-release experiment and the drug-release-rate constants reflecting the drug release characteristic of polymer microspheres were obtained by constituting a mathematical model. The results indicated that the homopolymer PAlAm microspheres and the copolymer PAIAm-g-PIPA microspheres are both pH responsive to release P N and that in the neutral pH condition the release rate is the slowest.