Artemether-lumefantrine nanostructured lipid carriers for oral malaria therapy: Enhanced efficacy at reduced dose and dosing frequency.

Artemether-lumefantrine (ARM-LFN) is a World Health Organization (WHO) approved fixed-dose combination having low solubility and poor oral bioavailability. Nanostructured lipid carriers (NLC) were developed to enhance the oral efficacy of this combination using the microemulsion template technique. They were characterized for drug content, entrapment efficiency, size distribution, in vitro release, antimalarial efficacy, and toxicity. The NLC showed sustained drug release. The recommended adult therapeutic dose is 80mg ARM and 480mg LFN (4 tablets) twice a day, which amounts to 160mg ARM and 960mg LFN daily. ARM-LFN NLC given once a day at 1/5 of therapeutic dose (16mg ARM and 96mg LFN) showed complete parasite clearance and 100% survival in Plasmodium berghei-infected mice. 33% of the mice treated with marketed tablets twice a day at the therapeutic dose showed late-stage recrudescence. Thus, NLC showed enhanced efficacy at 1/10 of the daily dose of ARM-LFN. The 10-fold reduced daily dose was formulated in two soft gelatin capsules thus reducing the number of units to be taken at a time by the patient. The capsules showed good stability at room temperature for a year. The NLC were found to be safe in rats. The biocompatible NLC developed using an industrially feasible technique offer a promising solution for oral malaria therapy.