Evaluation of excipient potentials of Irvingia wombolu fats and Moringa oil in rifampicin-loaded lipospheres: in vitro-in vivo characterisation

The aims of the study were to investigate the excipient potentials of two natural lipids from Irvingia wombolu and Moringa oleifera in rifampicin-loaded lipospheres. Lipospheres were formulated using different ratios of structured lipid matrices comprising of Phospholipon 90H (P90H) and Irvingia wombolu fats (IWF), and Phospholipon 90G (P90G) and Moringa oil (MO), respectively. Different in vitro test were studied including the particle size, encapsulation efficiency (EE), stability of formulations in simulated gastric fluid (SGF, pH 1.2), in vitro drug release, minimum inhibitory concentrations (MIC) and in vivo release. Results showed spherical particles within the size limit for lipospheres. Highest EE of 91.6 % was obtained. The lipospheres protected rifampicin against acidic degradation in the stomach (p < 0.05) and exhibited in vitro release of about 71.9 % at 12 h. In vivo release showed that the formulations had significantly higher in vivo absorption than the pure rifampicin sample (p < 0.05) and also showed higher antibacterial properties against Bacillus subtilis and Escherichia coli (p < 0.05). Rifampicin-loaded lipospheres had sustained release properties and could be used for once daily administration.