Potential of nanoemulsions for intravenous delivery of rifampicin

The aim of the present study was to develop, characterize and evaluate nanoemulsion formulations for intravenous delivery of rifampicin (RIF). Different oil-in-water (o/w) nanoemulsions were prepared by the aqueous phase titration method. Prepared nanoemulsions were subjected to thermodynamic stability tests for phase separation, creaming, cracking, coalescence or phase inversion and dispersibility test for dilution capacity. Nanoemulsion formulations which passed these tests were characterized in terms of droplet size, viscosity, entrapment efficiency, homogeneity and pH. The selected formulations were subjected to in vitro dissolution studies using a dissolution apparatus-XXIII in dialysis bag. Best results were obtained with the formulation which consisted of 150 mg of RIF, 15% w/w of Sefsol 218, 18.75% w/w of Tween 80, 6.25% w/w of Tween 85 and 60% w/w of normal saline. The optimized formulation was also subjected to stability studies according to the ICH guidelines. The formulation was found to be stable for more than 19 months. These results indicated the potential of nanoemulsions for intravenous delivery of RIF.