Development and characterization of exendin-4 loaded self-nanoemulsifying system and <i>in vitro</i> evaluation on Caco-2 cell line.

Aim of this study was to develop exendin-4 and exendin-4/chymostatin loaded self-nanoemulsifying drug delivery system (SNEDDS). Surfactants and co-surfactants were mixed, oil phase containing exendin-4 or exendin-4/chymostatin was added dropwise for SNEDDS. Short term physical stability test was performed prior to the release, lipolysis and permeability studies. SNEDDS containing ethyl oleate: Cremophor EL: Labrasol: propylene glycole (15:42.5:21.25: 21.25) were selected for release and intestinal permeability studies for suitable parameters and physical stability test results. SNEDDS were obtained which yielded Grade B nanoemulsions having droplet size below 25 nm. release studies showed that 73.79% of the peptide was released for 2 h at pH 6.8. Both exendin-4 and exendin-4/chymostatin loaded SNEDDS were non-toxic to Caco-2 cells. Permeability coefficients of both exendin-4 loaded SNEDDS and exendin-4/chymostatin loaded SNEDDS were higher than exendin-4 solution. Intestinal permeability of exendin-4 has been improved by SNEDDS formulations.