EFFECT OF AQUEOUS EXTRACT OF CRYPTOLEPIS SANGUINOLENTA ON PHARMACOKINETICS OF CHLOROQUINE
The effect of aqueous extract of Cryptolepis sanguinolenta on the pharmacokinetics of chloroquine was studied in male Sprague-Dawley rats. This study was necessitated as a result of the upsurge in the practice of concurrent administration of antimalarial preparations, most of which contain Cryptolepis sanguinolenta and some orthodox antimalarials in Ghana. Reconstituted freeze dried Cryptolepis sanguinolenta was administered in drinking water at the therapeutic dose of 36 g/kg body weight for two (2) weeks, followed by a single oral dose of chloroquine (15 mg/kg body weight). The Concentration - Time course; Maximum whole blood concentration, Cmax; Time for the maximum concentration, Tmax; Bioavailability; Elimination Rate Constant; Half- life; Clearance; Volume of Distribution and Absorption rate constant were measured. About 86% of chloroquine was recovered during extraction. The results of the study revealed that concurrent administration of Cryptolepis sanguinolenta and chloroquine caused an decrease (p < 0.05) in the absorption rate constant (65.2%), maximum whole blood concentration (43.9%), elimination rate constant (52.0%) and clearance (51.0%) of the later drug, resulting in an increase (p < 0.05) in half-life (109.0%) and bioavailability (99.4%) of the chloroquine in the blood. The findings could therefore partly explain the development of resistance of the plasmodium parasite to chloroquine.