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Evidence-Based Complementary and Alternative Medicine
Volume 2013, Article ID 324618, 6 pages
Research Article

Effect of the African Traditional Medicine, Sutherlandia frutescens, on the Bioavailability of the Antiretroviral Protease Inhibitor, Atazanavir

1Division of Pharmaceutics, Faculty of Pharmacy, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa
2Biopharmaceutics Research Institute, Rhodes University, P.O. Box 94, Grahamstown 6140, South Africa

Received 15 July 2013; Revised 5 November 2013; Accepted 6 November 2013

Academic Editor: Zhong Zuo

Copyright © 2013 Adrienne C. Müller et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The objective of this study was to investigate the effect of Sutherlandia frutescens (SF) on the bioavailability of atazanavir (ATV) in twelve healthy male subjects. During Phase I (Day 1), subjects ingested a single dose of ATV and blood samples were drawn before dose and at 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 5.0, 6.0, 9.0, 12, 18, and 24 hours after dose. From Day 3 to Day 14, a single dose of milled SF was administered twice daily to each subject. During Phase II, Day 15, subjects ingested single doses of ATV and SF. Blood samples were drawn as previously described. Plasma was harvested from blood samples and the concentration of ATV therein was determined. For each phase, the mean ATV plasma concentration-time profile was plotted and the means of and for ATV were computed. The geometric mean ratios and confidence intervals (CIs) for and were 0.783 (0.609–1.00) and 0.801 (0.634–1.01), respectively. The CIs for both PK parameters fell below the limits of the “no-effect” boundary, set at 0.8–1.25, indicating that SF significantly reduced the bioavailability of ATV. This may potentially result in subtherapeutic plasma concentrations and thus reduced anti-HIV efficacy of ATV.