Pharmacokinetic evaluation of novel pH-sensitive poly(2-methoxyethyl methacrylate-co-itaconic acid) microgels in rabbits

Novel copolymeric microgels of 2-methoxyethyl methacrylate and itaconic acid have been proposed for pH-responsive oral delivery of therapeutics. In vitro evaluation confirmed the potential of p(MEMA-co-IA) microgels to protect the drug from harsh environment of stomach and to deliver drug in response to pH of the external environment over extended period of time. In the present study, p(MEMA-co-IA) microgels have been evaluated for the pharmacokinetic parameters of model drug, esomeprazole in rabbits. Single-dose noncompartmental study was conducted by oral administration of drug solution and drug-loaded microgel. On comparison, it was found that the microgels have delayed the release of drug to about 2 hr, with decreased C-max, prolonged t(max), increased AUC(0-t,) and prolonged MRT. The differences were statistically significant. In conclusion, p(MEMA-co-IA) microgels have potential for preferential drug delivery into higher pH environment over prolonged period of time.