Development and Evaluation of Liquid and Solid Self-microemulsifying Drug Delivery System of Lovastatin

Abstract

Aim: The present investigations was aimed to improve the solubility, dissolution rate and ultimately the bioavailability of a poorly water soluble BCS class II drug Lovastatin, by formulating it as self-microemulsifying drug delivery system (SMEDDS). Materials and Methods: Liquid SMEDDS of the drug were formulated using Labrafil M 1944, Acrysol EL 135 and Lauroglycol as oil, surfactant and co-surfactant respectively. The prepared systems were characterized for self-emulsification time, robustness to dilution, % transmittance, globule size and thermodynamic stability. Ternary phase diagrams were plotted to identify the area of microemulsification. The optimized liquid SMEDDS was transformed into free flowing powder using Neusilin US2 as the adsorbent. Results and Discussion: Self microemulsifying powder retained the self microemulsifying property of the liquid SMEDDS. Differential scanning calorimetric and X-ray powder diffraction studies confirmed solubilization of the drug in the lipid excipients and or transformation of crystalline form of the drug to amorphous one in solid-SMEDDS. This was supported by scanning electron microscopy studies which did not show evidence of precipitation of drug on the surface of the carrier. In-vitro dissolution studies revealed enhanced release of the drug from solid-SMEDDS as compared to pure drug and the marketed formulation. Similarly the in-vitro absorption studies revealed significant enhancement in drug release from the SMEDDS as compared to plain drug suspension. Conclusion: It can be concluded that the SMEDDS formulation of Lovastatin has the potential of improved delivery of the lipophilic drug and is amenable to development of solid dosage form using Neusilin US2 as the porous carrier.