A New Vehicle that Increases the Efficacy of Antimalarial Drugs

 A study led by Dr. Xavier Fernández-Busquets, researcher at ISGlobal, and published in the Journal of Controlled Release, describes a new strategy for the efficient delivery of antimalarial drugs. The strategy, based on lipid vesicles (liposomes) studded with antibodies against red blood cells (also called erythrocytes), allows the drug to enter the cell, infected or not, and destroy the parasite at the very moment of invasion. The project was performed in collaboration with researchers from GlaxoSmithKline.

The majority of drugs against the malaria parasite (Plasmodium sp.) are not soluble in water and thus are rapidly metabolized in the liver.  This is compensated through the administration of increased doses, although it is not easy to find a balance between high overall amounts causing toxic effects and low local amounts leading to selection of resistant parasites.  Therefore, it is urgent to find alternative drug delivery approaches that increase their half life or target them specifically to the infected cells. In this study, the researchers loaded chloroquine and primaquine (two antimalarial drugs) into liposomes covered by an antibody that specifically recognizes a cell surface protein expressed by erythrocytes, the target cells of Plasmodium.   

The results show that such immunoliposomes display a high specificity for erythrocytes and mediate drug release into the cell. Using a malaria mouse model, they show that immunoliposomes were much more efficient in clearing the parasite, as compared to the free drug or to liposomes without antibodies. The authors propose that the immunoliposome effect is both therapeutic and prophylactic, since the antibody recognizes all erythrocytes and can therefore target the drug to erythrocytes even before its invasion by the parasite.  

Dr. Fernández-Busquets is also affiliated to the Institute of Bioengineering of Catalonia (IBEC) and the Institute of Nanoscience and Nanotechnology  of the University of Barcelona (IN2UB).   

Reference:

Moles E, Urbán P, Jiménez-Díaz MB, Viera-Morilla S, Angulo-Barturen I, Busquets MA, Fernàndez-Busquets X. Immunoliposome-mediated drug delivery to Plasmodium-infected and non-infected red blood cells as a dual therapeutic/prophylactic antimalarial strategy. J Control Release. 2015. Jul 28;210:217-29.