Existence of antimalarial formulations with low bioavailability in Tanzania

• Published in: Tropical doctor Vol. 36; no. 2; p. 93
• Main Authors: Minzi, Omary M S, Massele, Amosy, Justin-Temu, Mary, Ericsson, Orjan, Gustafsson, Lars L
• Format: Journal Article
• Language: English
• Published: England 01-04-2006
• Subjects: Adult; Antimalarials - pharmacokinetics; Area Under Curve; Biological Availability; Cross-Over Studies; Drug Combinations; Drugs, Generic - pharmacokinetics; Female; Humans; Malaria, Falciparum - drug therapy; Male; Middle Aged; Pyrimethamine - pharmacokinetics; Quality Control; Single-Blind Method; Sulfadoxine - pharmacokinetics; Tanzania; Therapeutic Equivalency; Tanzania
• ISSN: 0049-4755
• DOI: 10.1258/004947506776593512

The main objective of this work was to assess the relative bioavailability of two tablet formulations containing sulfadoxine/pyrimethamine (SP) and marketed in Tanzania. Twelve healthy volunteers were randomized to receive a single oral dose of three SP tablets each containing 500 mg sulfadoxine (SDX) and 25 mg pyrimethamine (PYR) in a form of either A (a locally manufactured SP tablet formulation, manufactured by a local pharmaceutical industry in Tanzania) or B (Fansidar), Hoffmann La Roche, Basel, Switzerland, an innovator's SP) after an overnight fasting. Serial blood samples (100 microL) were collected from a finger prick in duplicate up to 10 days and dried on Whatman filter paper. The samples were assayed for SDX and PYR using high-performance liquid chromatographic methods. Pharmacokinetic parameters of SDX and PYR were estimated by single compartment method. The pharmacokinetics of formulation A--maximum plasma concentration, the areas under the plasma concentration--time curve and the relative bioavailability (A versus B) were significantly lower than those of formulation B (P < 0.1). These observed differences indicate bioinequivalence between the two products.