Formulation and Evaluation of Capsules From Azadirachta indica and Khaya senegalensis for Malaria Treatment

Malaria is a major public health problem, prevalent in Africa and endemic in Ghana. Besides the use of artemisinin combination therapy, plant medicine is well‐recognised and accepted in Ghana. Decoctions of Azadirachta indica (AI) leaves and Khaya senegalensis (KS) stem bark are traditionally used for treating malaria. However, these decoctions are bitter, bulky and unstable compared to solid dosage forms. This study sought to formulate decoctions from these plants into capsules to tackle these setbacks. The maximum wavelength of absorption and the amount per dose of both plants’ decoctions (120 mL) were determined. Four absorbents (bentonite, magnesium carbonate, microcrystalline cellulose and kaolin) at four concentrations (25, 50, 75 and 100 mg/dose) were used to formulate the decoctions into granules. The granules were assessed to select the best extract‐absorbent granules for encapsulation and quality assessment. Antiplasmodial activity and cytotoxicity of the formulated capsules were also determined. AI containing 35 mg/dose of kaolin with a percentage release of 97.31 ± 0.74% and good flow properties was encapsulated. KS containing 50 mg/dose of bentonite with a percentage release of 97.54 ± 0.88% and good flow properties was encapsulated. Formulated capsules from both plants passed all quality control tests performed, with disintegration times of 10.01 ± 0.34 and 4.48 ± 0.23 min, and cumulative drug release of 78.13 ± 0.37% and 95.63 ± 1.00%, for AI and KS, respectively. AI (IC 50 , 2.74 ± 0.70 μg/mL) and KS (IC 50 , 24.37 ± 4.19 μg/mL) had good to moderate antiplasmodial activity (IC 50 ≤ 50 μg/mL) using the SYBR green assay. Cytotoxicity studies also indicated that both AI and KS were selective for the Plasmodium parasite. The formulated capsules could therefore be used as an alternative to their bitter decoctions.