Nanoparticles as Drug Carriers—a New Strategy That Could Limit the Development of Resistance in Malaria Parasites

A study carried out by researchers from CRESIB, ISGlobal's research centre, and the Institute for Bioengineering of Catalonia (IBEC) has demonstrated that an antimalarial drug encapsulated in nanoparticles—chloroquine salts in polyamidoamine polymers (AGMA1 and ISA23)—is significantly more effective in vivo than free drug and can therefore help to limit the development of drug resistance. The study, which was published in the Journal of Controlled Release, indicates that the nanoparticles is capable of recognising a number of Plasmodium species, making their potential scope as adjuvants for malarial drugs broader than that of other carriers.

Current malaria therapies require strategies capable of selectively delivering drugs to the cells parasitised by Plasmodium. In this study, researchers have explored the usefulness of the polymeric nanosystems AGMA1 and ISA23 as adjuvants for antimalarial drugs that selectively target the pathogen. The polymeric salt AGMA1 also has antimalarial activity, which is demonstrated by its inhibition of the growth of Plasmodium falciparum in vitro. The study showed that both polymers bind preferentially to Plasmodium-infected red blood cells compared to uninfected cells. Moreover, they are capable of recognising widely divergent species, such as P falciparum and Plasmodium yoelii, malaria parasites that infect humans and mice, respectively. Intraperitoneal administration of 0.8 mg/kg of chloroquine as either AGMA1 or ISA23 salts cured P yoelii-infected mice, whereas control animals treated with twice as much free drug did not survive.

Xavier Fernàndez Busquets, the ISGlobal researcher who led the study, explains that "these polymers which can encapsulate antimalarial drugs have low toxicity, high biodegradability and selective internalisation into Plasmodium-infected red blood cells targeting species as divergent as human and rodent malarias. All this makes them promising candidates in the field of therapeutic antimalarials."

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