Formulation and evaluation of transdermal nanogel for delivery of artemether.

Artemether (ART) is second to artesunate in being the most widely used derivatives of artemisinin in combination therapy of malaria. Nanostructured lipid carrier (NLC) formulations were prepared following our previous report using optimized ART concentration of 0.25 g dissolved in 5% w/v mixture of solid (Gelucire 43/01 and Phospholipon 85G) and liquid (Transcutol) lipids at 90 °C. An aqueous surfactant phase at 90 °C was added (dropwise) under magnetic stirring (1000 rpm) for 5 min. The pre-emulsion was speedily homogenized at 28,000 rpm for 15 min and further probe sonicated at 60% amplitude (15 min). Resultant sample was cooled at room temperature and frozen at - 80 °C prior to lyophilization. The freeze-dried sample was used for solid-state characterization as well as in the formulation of transdermal nanogels using three polymers (Carbopol 971P, Poloxamer 407, and Prosopis africana peel powder) to embed the ART-NLC, using ethanol as a penetration enhancer. Transdermal ART-nanogels were characterized accordingly (physical examination, pH, drug content, rheology, spreadability, stability, particle size and morphology, skin irritation, in vitro and ex vivo skin permeation, and analysis of permeation data), P < 0.05. Results indicated that ART nanogels showed good encapsulation, drug release, pH-dependent swelling, stability, and tolerability. Overall, ART nanogels prepared from Poloxamer 407 showed the most desirable drug permeation, pH, swellability, spreadability, viscosity, and transdermal antiplasmodial properties superior to PAPP-ANG > C971P-ANG. A two-patch/week concurrent application of the studied nanogels could offer 100% cure of malaria as a lower-dose (50 mg ART) patient-friendly regimen devoid of the drug's many side effects.