Novel Drug Delivery Approach via Self-Microemulsifying Drug Delivery System for Enhancing Oral Bioavailability of Asenapine Maleate: Optimization, Characterization, Cell Uptake, and In Vivo Pharmacokinetic Studies

Asenapine maleate (AM)-loaded self-microemulsifying drug delivery system (AM-SMEDDS) was prepared to increase its oral bioavailability. AM-SMEDDS was developed using Capryol 90, Cremophor EL, and Transcutol HP as oil, surfactant, and cosurfactant, respectively, by spontaneous emulsification method. Pseudoternary diagram showed maximum region at 3:1 ratio of Cremophor EL/Transcutol HP. The AM-SMEDDS showed globule size and zeta potential of 21.11.2nm and -19.31.8mV, respectively. Globules were found to be of spherical shape and uniformly distributed by transmission electron microscopy. In vitro drug release study showed 99.2 +/- 3.3% of drug release at the end of 8h in phosphate buffer pH 6.8. Ex vivo drug release study showed only 15% of drug diffusion through stomach and similar to 85% drug was diffused through intestinal membrane. Confocal and flow cytometry study showed that cellular uptake of coumarin-6 loaded SMEDDS was significantly enhanced by Caco-2 cells as that of coumarin-6 solution. The relative bioavailability of AM-SMEDDS was found to be 23.53 times greater than AM suspension. Intestinal lymphatic transport study using Cycloheximide(CHX) showed that the AUC(total) of AM-SMEDDS reduced about 35.67% compared with that without the treatment ofCHX indicating involvement of lymphatic system in intestinal absorption of AM-loaded SMEDDS. These findings demonstrated the potential of SMEDDS for oral bioavailability improvement of AM via lymphatic uptake.