Enhanced Oral Bioavailability of Atorvastatin via Oil-in-Water Nanoemulsion using Aqueous Titration Method

Atorvastatin, a highly lipophilic anti-hyperlipidemic drug, has poor oral bioavailability (14%) due to hepatic first pass effect. The present study aimed at developing an optimal oral nanoemulsion formulation containing an atorvastatin using different proportions of oil and surfactant systems for enhancing its oral bioavailability. Pseudoternary phase diagrams were constructed by aqueous titration technique and various nanoemulsion formulations were prepared. Formulations selected from the o/w nanoemulsion region were subjected to various thermodynamic stability and dispersibility tests. Optimized formulations were evaluated for various physicochemical characterization tests. The in vitro dissolution studies revealed that release of atorvastatin from nanoemulsion was faster than the conventional tablet (Ozovas ) and pure drug suspension. The formulation used for assessment of bioavailability contained 15% of oil (Oleic acid), 18% mixture of surfactants (Tween 80 and Brij 35), 6% of co-surfactant (ethanol) and 61% of double distilled water. The absorption of atorvastatin from nanoemulsion resulted in 2.87and 2.38-fold increase in bioavailability as compared to conventional tablet and pure drug suspension respectively. Thus, the study confirmed that the nanoemulsion formulation can be used as a possible alternative to traditional oral formulation of atorvastatin to improve its bioavailability.