Synthesis of pH and temperature sensitive hydrogels and modelling of drug release behavior

Recent years, due to their remarkable properties, studies upon hydrogels in many fields and particularly in medical science for drug release are gained great importance. In this study, by using thermosensitive NIPA monomer and pH sensitive AAc as comonomer, poly(NIPA-co-AAc) microgels were synthesized by free radical emulsion polymerization. Then, poly(NIPA-co-AAc) interpenetrated networks (IPN) hydrogels were prepared by free radical solution polymerization in the presence of poly(NIPA-co-AAc) microgels. The synthesized IPN gels in glass tube were cut into pieces in cylindrical shapes. Investigations were made on synthesized IPN hydrogel swelling and results show that swelling degree increases when AAc amount increases in the gel. Also the effects of pH and temperature on swollen hydrogel at equilibrium were studied. During two days a synthesized dry IPN poly(NIPA-co-AAc) hydrogel was immersed in 200 ppm riboflavin B2 vitamin solution for drug loaded by swelling. The amount of drug absorbed into the matrix of the hydrogel was 21.33mg/g riboflavin drug and the releases were made in different pH and temperature mediums. The drug release results show that the release was dependent on pH and temperature. Drug release modeling was made by response surface methodology (RSM)-centralcomposite design of Design Expert-10 software (trial-version) and artificial neural networks (ANNs) in MATLAB. Best performance was found on ANNs results.