Self-microemulsifying drug delivery system as carrier for the oral delivery of glimepiride: Formulation development, optimization, in-vitro characterization, stability assessment, ex-vivo permeation, and in-vivo antidiabetic activity in albino mice

Aim: The research aimed to design the glimepiride self-micro emulsifying drug delivery system (SMEDDS) for increased oral bioavailability in albino mice by assessing hypoglycemic efficacy.

Materials and Methods: The optimized liquid SMEDDS (L-SMEDDS) prepared by emulsification of Capryol® 90 (oil), Kolliphore® EL (surfactant), and Transcutol® P (co-surfactant) were screened based on their solubility in glimepiride. Adsorption onto Aerosil® 200 Pharma produced solid SMEDDS (S-SMEDDS), and further direct compression was used to manufacture the tablets. The formulations were subjected to droplet size, polydispersity index (PdI), time of emulsification, in-vitro drug release, crystallinity nature, surface morphology, thermal behavior, ex-vivo permeability, and in-vivo hypoglycemic activity in albino mice.

Results: The SMEDDS emulsified in less than 30 sec and had an average droplet size of 22.3 nm with a PdI of 0.296. The solid-state analysis revealed that glimepiride was in a molecular dispersion or amorphous form. In-vitro release experiments demonstrated that glimepiride released more efficiently than plain glimepiride. Both L-SMEDDS and S-SMEDDS did not have any significant differences in terms of release. The ex-vivo and in-vivo studies revealed that SMEDDS possess improved permeability and hypoglycemic activity than plain glimepiride.

Conclusion: The study proved the combination of lipid-based nanosystems with oral dosage forms improved the oral bioavailability of glimepiride SMEDDS.