The antimalarial drug dihydroartemisinin: Formulation design and challenges in drug development

Abstract

Malaria is an important cause of death and illness in children and adults, especially in tropical countries. Artemisinin-based combination therapy is currently the gold standard of antimalarial therapy, recommended in the WHO Guidelines. Artemisinin, also called qinghaosu, is naturally occurring sesquiterpine lactone endoperoxide isolated from the traditional Chinese medicinal plant qinghao. Artemisinin shows a potent antimalarial activity against resistant strains of Plasmodium falciparum and cerebral malaria. Artemisinin and its derivatives are metabolized to an active metabolite, dihydroartemisinin (DHA). DHA is an effective antimalarial drug, especially against the tolerant species of Plasmodium falciparum. Unfortunately, DHA possesses poor water solubility, leading to low bioavailability. There are many attempts to improve the dissolution and bioavailability of DHA such as inclusion complexation with cyclodextrins, solid dispersion, nanosuspension, microfluidization, micronization, and surfactant addition. Some reports on dosage form design, formulation and processing of DHA formulations and delivery systems are presented and discussed.