ORIGINAL ARTICLE Formulation and evaluation of self-emulsifying orlistat tablet to enhance drug release and in vivo performance: factorial design approach Mukund Maruti Gade 1 & Pramod Jayadevappa Hurkadale 1 # Controlled Release Society 2016 Abstract The purpose of the present research work was to formulate, evaluate, and optimize self-emulsifying orlistat tablet to enhance drug release followed by in vivo antiobesity activity in Wistar rats. Initially, the solubility of orlistat was determined in different natural oils, surfactant, and co-surfactants. Self-emulsifying drug delivery system (SEDDS) was prepared by using castor oil, Tween 80, and Capryol PGMC as compo- nents. Liquid SEDDS evaluated for globule size and emulsification time. A 3 2 full factorial design was uti- lized for the optimization purpose. Formulation variables such as quantity of oil (X1) and ratio of surfactant to co-surfactant (X2) were investigated for their effect on globule size and emulsification time. Optimized formu- lation with minimum globule size was freeze-dried which further compressed into the tablet. Finally, opti- mized formulation evaluated for the in vitro drug release study followed by weight losing potential in Wistar rats. Globule size and emulsification time for the optimized formulation were found to be 96.4 ± 8.5 nm and 26 ±4 s, respectively. Fourier transform infra red spectros- copy (FTIR) studies indicated that there was no interac- tion between drug and excipients. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) study revealed that there was the conversion of crystalline orlistat to the amorphous form. Orlistat release from the self-emulsifying tablet formulation was faster with higher weight reduction potential in Wistar rats than the marketed formulation. Increased in vitro drug re- lease with considerable in vivo weight loss by self- emulsifying tablet suggests that the SEDDS could serve as potential formulation strategy for orlistat. Keywords Orlistat . Self-emulsifying drug delivery system (SEDDS) . Freeze-drying . Self-emulsifying tablet Introduction Recently, self-emulsifying drug delivery system (SEDDS) attracted substantial attention of the re- searchers due to its inbuilt ability to carry drug candi- date in dissolved form/state at the site of absorption or action, which is pre-requisite for the drug candidate to be absorbed by biological membrane. SEDDS is defined as an isotropic mixture of the oil, surfactant, and co- surfactant/solvent of natural or synthetic origin, which may be in solid or liquid form. These are anhydrous liquid mixtures called as pre-concentrates. SEDDS spreads easily in the gastrointestinal tract whereas intes- tinal motility provides agitation, which results into the self-emulsification. SEDDS is thermodynamically highly stable system, which is able to form a spontaneous emulsion. Therefore, SEDDS has emerged as the effec- tive drug delivery system, which helps to enhance sol- ubility and bioavailability of water-insoluble active pharmaceutical ingredients [1–3]. SEDDS is reported to have less inter- and intra-subject variability in plasma drug level on administration. Self-emulsifying drug de- livery system is one of the popular formulation * Mukund Maruti Gade mukundgade09@gmail.com 1 Department of Pharmaceutical Biotechnology, KLE University’ s College of Pharmacy, Nehrunagar, Belagavi 590010, Karnataka, India Drug Deliv. and Transl. Res. DOI 10.1007/s13346-016-0289-8