Nano scale self-emulsifying oil based carrier system for improved oral bioavailability of camptothecin derivative by P-Glycoprotein modulation

Irinotecan is a camptothecin derivative with low oral bioavailability due to active efflux by intestinal P-glycoprotein receptors. Hence, no oral formulation is marketed for Irinotecan till date. However, an optimized Self micro emulsifying drug delivery system (SMEDDS), formulated to produce nano range oil droplets by using P-gp modulator excipients can tackle the issue and elevate the systemic availability of Irinotecan. The present work focuses on the development of SMEDDS for Irinotecan and evaluation of its in vitro, ex vivo and in vivo potentials. The SMEDDS were developed using Capmul MCM-C8, Cremophor EL and Pluronic L-121 as oil, surfactant and co-surfactant respectively and has good oil carrying capacity (30%) with competence to produce nano-scale oil droplets (130 ± 2.13 nm) on spontaneous emulsification. A much deeper penetration to the intestine was observed with SMEDDS by using confocal laser scanning microscopy (CLSM). Flow-cytometric studies also revealed the greater uptake of fluorescent probe in Caco-2 cell-lines with the use of SMEDDS. Biochemical estimation of LDH from the intestinal tissues treated with SMEDDS and free drug suspension confirmed that the developed formulation is safe for use. Furthermore, the AUC 0 → t of Irinotecan from the optimized SMEDDS formulation was found to be 4 folds higher than that from Irinotecan suspension on oral administration. The optimized SMEDDS formulation was found to be capable of maintaining the sustained plasma drug level of Irinotecan with better bioavailability.