Radiation preparation of drug carriers for dexamethasone and tegafur based on poly(n-isopropylacrylamide) hydrogels

Abstract

Poly(N-isopropylacrylamide) (PNIPAM) based hydrogels with the lower critical solution temperature (LCST) near the human body-temperature have been obtained from 10% solutions of N-isopropylacrylamide (NIPA) and N,N’-dimethyl acrylamide(DMA) mixture of 90:10 and 85:15 (w/w) by radiation copolymerization and crosslinking using a gamma Co-60 source at a dose of 20 kGy. Water swelling behaviour of the resulting hydrogels was much dependent on the initial ratio of NIPA and DMA. The hydrogels of 85:15 NIPA/DMA was chosen for further investigation for the use as drug cariers.Two kinds of drug carriers were prepared by immerging the hydrogels in solutions containing dexamethasone and tegafur. Then the drug incorporation efficiencies and in-vitro release behaviors of the ingredient were analysed. Loading capacities of the hydrogels were about 48.6 and 95.7 mg per g of dried gel for dexamethasone and tegafur, respectively. The results also revealed that the presence of ions in simulated body fluid and solution temperature much affected to the release behaviors of hydrogels for both dexamethasone and tegafur. Release rates of the ingredients were quite fast for both drug models. These drug-loaded hydrogels were biocompatibility without skin irritation suggesting that they may be used as controlled release drug carriers.