Optimized Artemether-loaded Anhydrous Emulsion.

Objective: The objectives of this study were to identify stable anhydrous emulsions via pseudo ternary phase diagram, optimize artemether-loaded batches using factorial design and subsequently evaluate the antimalarial activity. Methodology: Using labrasol®, triacetin® and lauroglycol 90® as the surfactant, oil and co-surfactant respectively, pseudo ternary phase diagram was generated from the quantitative titration of water with the anhydrous emulsion. Stable combinations from the phase diagram were subjected to a 23 full factorial experimental design. The 22 softwaregenerated formulations were experimentally formulated and characterized for droplet size, polydispersity index, viscosity and thermodynamic stability. Droplet size was chosen and subsequently fitted into the Response column of the software, thus prompting the generation of graphs and Desirability table of 125 predicted formulations. Out of the 125 predictions, three with the least droplet sizes (less than 100 nm) were adjudged as optimized batches. Subsequently, they were formulated, converted to powder by adsorption on magnesium aluminum metasilicate and evaluated. Antimalarial effectiveness of the drug-loaded formulation was also investigated. Results: Triacetin® most significantly (P<0.05) contributed to droplet size variation. The droplet size of the experimental formulations approximated that of the statistical predictions. The anhydrous emulsions (AEs) were powderable and the granulations rated fair and passable according to Carr’s scale. Artemether-loaded anhydrous emulsion (AE) demonstrated highest antimalarial activity. Conclusion: We therefore conclude that optimization proved a useful tool for the identification of excipient proportions with optimal effects.