Formulation of nanoemulsion: a comparison between phase inversion composition method and high-pressure homogenization method

Abstract There is lot of confusion in the literatures regarding the method of production of nanoemulsion. According to some authors, only the methods using high energy like high-pressure microfluidizer or high-frequency ultra-sonic devices can produce actual nanoemulsions. In contrast to this concept, one research group reported for the first time the preparation of nanoemulsion by a low-energy method. Later on many authors reported about the low-energy emulsification method. The purpose of this work is to formulate, evaluate and compare nanoemulsions prepared using high-energy as well as low-energy method. Nanoemulsions formulated were based on the phase inversion composition technique (low energy method) and were selected from the ternary phase diagram based on the criterion of their being a minimum concentration of Smix used in the formulation. For high-pressure homogenization method (high energy method) Design-Expert software was used, and the desirability function was probed to acquire an optimized formulation. No significant difference (p > 0.05) was observed in the globule size of formulations made by each method, but the value of poly-dispersibility index between the two methods was found to be extremely significant (p < 0.001). A very significant difference (p < 0.001) was observed in the drug release from formulations made by each method. More than 60% of the drug was released from all the formulations in the initial 2 h of the dissolution study.