Optimization of solid-self nanoemulsifying drug delivery system for solubility and release profile of clonazepam using simplex lattice design

The objective of the present work was to improve solubility and dissolution release properties of clonazepam (CNZ) from solid-self nanoemulsifying drug delivery system (S-SNEDDS). Liquid SNEDDS (L-SNEDDS) of CNZ was a system consisted of sunflower oil, Tween 80 and PEG 600 as vehicle, surfactant and co-surfactant, respectively. The L-SNEDDS were systematically optimized using simplex lattice design. The selected independent variables were % of sunflower oil (X 1 ), % of PEG 600 (X 2 ) and % of Tween 80 (X 3 ) and dependent variables were droplet size (Y DS ) and polydispersity index (Y PDI ). S-SNEDDS were prepared by simple adsorption technique using Aerosil ® 200 as inert solid carrier. Both L-SNEDDS and S-SNEDDS showed significantly improved in vitro drug release and ex-vivo permeation than pure drug. Solid state characterization (DSC, X-RD and SEM) studies revealed that complete conversion of crystalline CNZ to amorphous form in optimized SNEDDS formulation. FT-IR studies revealed that there was no chemical interaction between drug and excipients. Accelerated stability studies revealed that there was no significant changes in physical appearance, emulsification time, droplet size, PDI, assay and dissolution release profile before and after storage. The obtained results illustrate the perspective use of S-SNEDDS for the oral delivery of poorly water soluble drugs.