Evaluation of Pharmacokinetics, Biodistribution, and Antimalarial Efficacy of Artemether-Loaded Polymeric Nanorods

Artemether oily injection is recommended for the treatment of severe malaria by the intramuscular route. The major limitations of the artemisinin combination therapy are erratic absorption from the injection site and high dosing frequency due to a very short elimination half-life of the drug. Advanced drug delivery systems have shown significant improvement in the current malaria therapy; the desired drug concentration within infected erythrocytes is yet the major challenge. Recently, we have reported the fabrication of artemether-loaded polymeric nanorods for intravenous malaria therapy which was found to be biocompatible with THP-1 monocytes and rat erythrocytes. The objective of the present study was the evaluation of pharmacokinetics, biodistribution, and antimalarial efficacy of artemether-loaded polymeric nanorods. Scanning electron microscopy and confocal microscopy studies revealed that both nanospheres and nanorods were adsorbed onto the surface of rat erythrocytes after an incubation of 10 min. After intravenous administration to rats, artemether nanorods showed higher plasma concentration and lower elimination rate of artemether when compared with nanospheres. The biodistribution studies showed that, at 30 min, the liver concentration of DiR-loaded nanospheres was higher than that of DiR-loaded nanorods after intravenous administration to BALB/c mice. The in vitro schizont inhibition study showed that both nanorods and nanospheres exhibited concentration-dependent parasitic inhibition, wherein at lower concentrations (2 ppm), nanorods were more effective than nanospheres. However, at higher concentrations, nanospheres were found to be more effective. Nanorods showed higher chemosuppression on day 5 and day 7 than nanospheres and free artemether when studied with the Plasmodium berghei mouse model. Moreover, the survival rate of P. berghei infected mice was also found to be higher after treatment with artemether nanoformulations when compared with free artemether. In conclusion, polymeric nanorods could be a promising next-generation delivery system for the treatment of malaria.