Development and characterization of self-nanoemulsifying drug delivery systems (SNEDDS) of atorvastatin calcium

The main aim of the present investigation is to develop and characterize the self-nanoemulsifying drug delivery systems (SNEDDS) of atorvastatin calcium (ATV) for improving the dissolution thereby oral bioavailability and to minimize the gastric degradation. Naturally occurring different vegetable oils, various surfactants and co-surfactants were studied for ATV solubility to identify the components of SNEDDS. Ternary phase diagrams comprising surfactant, cosurfactant and oil were plotted. In the ternary phase diagrams the area of self-nanoemulsifying region was marked for the compositions that are giving dispersion with a globule size ≤ 200 nm. Effect of drug loading on the phase behavior of selected system was studied. A series of SNEDDS were prepared by selecting from the nanoemulsifying area of 2.5% ATV system. Prepared SNEDDS were evaluated for visual observations, turbidity, effect of pH of the dispersion media on globule size and zeta potential, robustness to dilution and in vitro dissolution study and optimized. FT-IR and DSC were studied for interaction between drug and excipients if any. Forced degradation and accelerated stability studies were conducted for optimized SNEDDS. ATVF 04 and 11 were selected as optimized SNEDDS due to their smaller mean globule size (75.2 and 85.8 nm respectively), lower turbidity values, faster drug release and higher DE values among the other SNEDDS. The optimized ATV SNEDDS were not affected by the pH of dissolution medium. FT-IR study revealed no interaction between drug and excipients used. Forced degradation studies indicated the stability of ATV in the gastric environment. Accelerated stability studies showed no significant changes in the mean globule size, zeta potential, drug content and drug release before and after storage of optimized SNEDDS.