Niosomes for enhanced oral delivery of pioglitazone: in vitro characterization and in vivo evaluation.

Abstract

Objectives: The aim was to investigate oleic acid and nigella oil modified niosomes as novel carriers for enhanced pioglitazone (PGZ) oral delivery.

Methods: PGZ was encapsulated into niosomes of cholesterol, tween 80, and span 60 before (F1) and after incorporation of nigella oil (F2) or oleic acid (F3) as membrane fluidizers. Niosomes were characterized for morphology, size, zeta potential, PGZ entrapment, and release. Hypoglycemic effect was also assessed.

Key findings: Vesicles were spherical recording size values of 286.4, 111.3, and 137.5 nm for F1, F2, and F3 niosomes, respectively. The zeta potential predicted good stability of niosomes. The lipophilic nature of PGZ resulted in more than 99% entrapment into niosomes. PGZ niosomes significantly boosted rate and extent of hypoglycemic activity compared with the unprocessed PGZ. This is clear from the Tmax, which was 3.6, 1.5, 0.87, and 0.62 h for control, F1, F2, and F3, respectively. This was associated with increase in the area above hypoglycemia curve, which was 655.8, 1613.6, 1617.2, and 1764.9 mg h/dl for the same formulations, respectively.

Conclusion: Vesicular structure is responsible for enhanced oral bioavailability and drug release is not the limiting factor. Fluidizing material showed potential contribution in enhanced efficacy but requires future verification.