Pharmacokinetic Interactions Between an Herbal Medicine (African Potato) and Antiretroviral Agents (Lopinavir/Ritonavir)

Inclusion Criteria: * Absence of HIV infection prior to study entry. * Male or female aged 18-60 who are able to provide informed consent. * Subject is within 20%(+/-) of ideal body weight and must weigh at least 550kg * Healthy subjects without evidence of acute or chronic illness including diabetes, hypertension, CAD, psychiatric illnesses, renal or hepatic impairment. * Screening laboratory tests that are normal or deemed not clinically significant by the study physician * Female subjects of childbearing potential must not be pregnant or lactating, must have a negative pregnancy test at screening and must be practicing an adequate method of birth control. Acceptable methods of birth control include use of an intrauterine device (IUD), oral, implanted or injected contraceptives, and barrier methods with spermicide. * Subjects must sign an informed consent that complies with US Regulations (US 21 CFR 50) and the International Conference on Harmonization (ICH) guidelines prior to undergoing any study-related procedures. * Subjects agreed to abstain from consuming grapefruit or its juice for at least 48 hours prior to dosing and throughout the study period until the last blood samples were being obtained. * Subjects agreed to abstain from consuming alcohol /alcoholic beverages for at least 24 hours prior to dosing and throughout the study period until the last blood sample were being obtained. * Subjects agreed to abstain from use of cigarettes and tobacco products for at least 24 hours prior to dosing and throughout the study period until the last blood samples were being obtained. * Subjects who agreed to be available for the entire study period and had the ability to understand and communicate with the investigators and staff. Exclusion Criteria: * Use of illicit drugs or alcohol that could interfere with the completion of the study. * Use of any over- the- counter or prescribed drugs unless approved by the principal investigator or study physician. * Use of drugs that are known to inhibit/ induce CYP450 isozymes or are substrates of CYP3A4, CYP2D6, CYP2C8 enzymes. (use of hormonal contraceptives is permitted except for oral contraceptives) * Pregnant or breast- feeding. * History of acute or chronic illnesses, such as diabetes, hypertension, CAD, psychiatric illnesses, renal or hepatic impairment. * Evidence of acute illness. * Family history of congenital prolongation of QTc interval or with any conditions known to prolong QTc interval, such as cardiac arrhythmias, bradycardia or severe heart disease * History of hypokalemia, hypomagnesemia or hypercholesteremia