Formulation of oral pharmaceutical dosage forms containing crude extracts of artemisia annua

Résumé

Artemisia annua is an asiatic plant with curative properties against malaria, containing artemisinin. This active compound, and its derivatives are the last few antimalarial drugs that remain effective against multidrug resistant strains of Plasmodium falciparum. But they are very expensive and not accessible to poor African countries.

The aim of this study is to obtain effective pharmaceutical dosage forms against malaria, starting from extracts of Artemisia annua cultivated in Benin.

Several extraction methods were compared based on the extraction yield of artemisinin and antiplasmodial activity tests. Artemisinin was quantified in each extract by an HPLC method with derivatization of artemisinin in Q260. The extraction yield of artemisinin was the highest by using Soxhlet extraction with petroleum ether 40-60 (0,262%). The infusion method led to the weakest extraction yield (0,194%). Intermediate results were obtained for maceration in oil ether (40-60) process (0,199%) and in the mixture water/ ethanol (50/50) (0,227%). The antiplasmodial tests in vitro were carried out by the method of Delhaes et al and revealed that maceration in water/ethanol would be most effective with a IC50 equal to 2,849 and very near to the results of the artemisinin as a reference (IC50 = 2,731). The hydro-alcoholic extract was evaporated in order to obtain a dry powder for the preparation of two oral drug dosage forms (hard gelatin capsules and oral suspension). These two formulations were tested for content uniformity, stability, and microbiological properties and all the tests were found to be conform to the Pharmacopeias recommendations.

The use of crude extracts of the plant can give cheaper and efficient medicines containing artemisinin and also other compounds of the plant with antipyretic properties and which can potentiate artemisinin antimalarial activity.

Keywords: Herbal medicinal products, Pharmaceutical dosage forms, drugs made with plants.