In the present investigation an attempt was made to enhance the solubility and dissolution of poorly soluble drug, isotretinoin, by formulating self-nanoemulsifying drug delivery system (SNEDDS). Liquid SNEDDSs were prepared using Transcutol P as oil, Tween 80 as surfactant, and PEG 400 as cosurfactant. Pseudoternary phase diagrams were constructed to identify the efficient self-nanoemulsification region. The formulation with 40% oil (Transcutol P) and 60% surfactant: cosurfactant (Tween 80: PEG 400) ratio of 1 : 1 was optimized based on evaluation parameters for droplet size analysis, self-emulsification capacity, zeta potential, andin vitrodrug release performance. The optimized system contains mean droplet size of 36.60 nm and zeta potential (ζ) −26.73 mV. The optimized formulation A1 was adsorbed onto Fujicalin to produce solid SNEDDS, which exhibited good flow properties and preserved the self-emulsification properties of liquid SNEDDS. The differential scanning calorimetry, FT-IR studies of solid SNEDDS revealed transformation of isotretinoin into molecularly dissolved state in the liquid SNEDDS.In vitrodissolution profiles showed that dissolution rate of ISN from solid SNEDDS was significantly greater as compared to pure drug.

SPHHs were synthesized by solution polymerization tech- nique. The synthesized SPHHs were characterized for tensile strength, swelling behavior, porosity, density, mucoadhesion time, SEM, DSC and FT-IR studies. In vitro drug release study from prepared vaginal formulation based on SPHH was performed in simulated vaginal fluid. Different mathematical models were applied to ascertain the drug release mecha- nism. SPHHs have shown good tensile strength, mucoadhesion time and drug release for 24 hour. SEM images reflected the formation of pores and interconnected capillary channels. The release kinetic of drug from the prepared system was best explained by Korsmeyer-Peppas and Higuchi models and shown anomalous transport. The proposed novel drug de- livery system based on SPHH was successfully prepared and SPHH-DDS might be promising candidate for topical vagi- nal delivery of Metronidazole.