Formulation, antimalarial activity and biodistribution of oral lipid nanoemulsion of primaquine.

Primaquine (PQ) is one of the most widely used antimalarial and is the only available drug till date to combat relapsing form of malaria especially in case of Plasmodium vivax and Plasmodium ovale. Primaquine acts specifically on the pre-erythrocytic schizonts which are concentrated predominantly in the liver and causes relapse after multiplication. However application of PQ in higher doses is limited by severe tissue toxicity including hematological and GI related side effects which are needed to be minimized. Lipid nanoemulsion has been widely explored for parenteral delivery of drugs. Primaquine when incorporated into oral lipid nanoemulsion having particle size in the range of 10-200 nm showed effective antimalarial activity against Plasmodium bergheii infection in swiss albino mice at a 25% lower dose level as compared to conventional oral dose. Lipid nanoemulsion of primaquine exhibited improved oral bioavailability and was taken up preferentially by the liver with drug concentration higher at least by 45% as compared with the plain drug.