Preparation and in vitro characterization of self-nanoemulsified drug delivery system (SNEDDS) of all-trans-retinol acetate

Purpose: To prepare a self-nanoemulsified drug delivery system (SNEDDS) of all-trans-retinol acetate, with enhanced dissolution and better chance of oral absorption. Method: All-trans-retinol acetate SNEDDS was prepared using different concentrations of soybean oil (solvent) Cremophor EL (surfactant) and Capmul MCM-C8 (co-surfactant). Particle size and turbidity of the SNEDDS were determined after adding water to the oily solution. Dissolution profile of SNEDDS filled in hydroxyl propyl methyl cellulose (HPMC) capsules was determined by using water in USP apparatus 2. Ternary phase diagrams were constructed to identify the self-nanoemulsified region. The SNEDDS were evaluated by the visual observation, turbidity in nephrometric turbidity units (NTU), mean particle size (mum) and Fourier transformed-infrared spectroscopy (FT-IR). SNEDDS were thermally characterized using differential scanning calorimetry (DSC) to ensure the compatibility of the SNEDDS ingredient. Results: From the data obtained in this work, it was clear that surfactant to co-surfactant ratio has the main impact on the physical characteristics of the emulsion formed. The optimum surfactant to co-surfactant ratio was found to be 2:1 (37.5-50% for Cremophor EL, and 18.75-25% for Capmul MCM-C8). With this ratio, the resultant nanoemulsions obtained have a particle size range of 0.103-0.051 mum, turbidity range of 18.12-2.18 NTU and t(30) values (cumulative% all-trans-retinol acetate dissolved in 30 min) of 90.42-99.5. Also the thermograms obtained from DSC experiments showed that there is no incompatibility or interaction between the SNEDDS ingredients (soybean oil, Cremophor EL, and Capmul MCM-C8) and all-trans-retinol acetate. Conclusion: The present study revealed that the self-nanoemulsified drug delivery system of all-trans-retinol acetate increased its dissolution rate and has the potential to enhance its bioavailability without interaction or incompatibility between the ingredients. (C) 2004 Elsevier B.V. All rights reserved.