Formulation and evaluation of solid self-microemulsifying drug delivery system for azilsartan medoxomil

This study aimed to develop solid self-microemulsifying drug delivery system (S-SMEDDS) for solubility enhancement of azilsartan medoxomil (AZL). Ternary phase diagrams were constructed using surfactant: co-surfactant at 1:0, 1:1, 1:2 and 2:1 ratios. Initially, the oils, surfactants and co-surfactants were screened. The drug–soya lecithin complexes were prepared and characterized for complexation percentage, complex solubility, and partition coefficient. The liquid SMEDDS were prepared and evaluated for thermodynamic stability, self-emulsification efficiency and time, viscosity, size and polydispersibility index, zeta potential, drug loading, and in vitro dissolution. Further, the solid SMEDDS were formulated and evaluated for morphological characterization, and thermal behavior. The solid SMEDDS were filled with hard gelatin capsule and accessed for in vitro drug release profile. S-SMEDDS containing Syloid^® XDP 3150 had highest adsorption capacity. Self-emulsification time, drug loading and percentage transmittance were 25 ± 1.23 s, 99.20 ± 0.11% and 99.3 ± 0.1%, respectively. Particle size, polydispersibility index and zeta potential were 201.0 nm, 0.544 and -19.7 mV, respectively. S-SMEDDS had good flow property, spontaneous self-microemulsification property and improved in vitro dissolution profile of AZL when compared to pure AZL.