Pharmacokinetics of Lopinavir/Ritonavir at Three Different Doses.

Data during the development of lopinavir/ritonavir showed that lower drug doses had similar efficacy to the standard dose of 400/100mg twice daily. Lower drug doses are also associated with limited toxicity and cost.

The purpose of this study is to assess the pharmacokinetics of plasma lopinavir/ritonavir following administration to male and female HIV-negative volunteers of 400/100mg, 200/150mg and 200/50mg lopinavir/ritonavir twice daily. Each dosing phase will last for 7 days and each phase will be separated by a 7-day wash-out period. Pharmacokinetic evaluations will be made over a 12-hour interval at the end of each dosing phase.

Healthy subjects as determined by their medical history and physical examinations will be eligible to participate in the study. HIV-positive subjects will not be recruited as there is a risk that HIV-resistant mutations will be selected by an experimentally reduced dose of lopinavir/ritonavir. There is no reason to presume that there is any meaningful difference in the metabolic processing of lopinavir/ritonavir between HIV-infected and HIV-uninfected people.

Inclusion criteria

• Subjects must meet all of the following inclusion criteria within 28 days prior to the baseline visit:

• The ability to understand and sign a written informed consent form, prior to participation in any screening procedures and must be willing to comply with all study requirements
• Male or non-pregnant, non-lactating females
• Between 18 to 65 years, inclusive
• Body Mass Index (BMI) of 18 to 35 kg/m2, inclusive.
• Women of childbearing potential (WOCBP) must be using an adequate method of contraception to avoid pregnancy throughout the study and for a period of at least 1 month after the study

Exclusion criteria

• Any significant acute or chronic medical illness
• Evidence of organ dysfunction or any clinically significant deviation from normal in physical examination, vital signs, ECG or clinical laboratory determinations
• Positive blood screen for hepatitis B core and/or C antibodies and/or hepatitis B surface antigen
• Positive blood screen for HIV-1 and/or 2 antibodies
• Current or recent (within 3 months) gastrointestinal disease
• Clinically relevant alcohol or drug use (positive urine drug screen) or history of alcohol or drug use considered by the Investigator to be sufficient to hinder compliance with treatment, follow-up procedures or evaluation of adverse events. Smoking is permitted, but tobacco intake should remain consistent throughout the study
• Exposure to any investigational drug or placebo within 3 months of first dose of study drug
• Consumption of grapefruit, or Seville oranges or any grapefruit or Seville orange containing product within one week of first dose of study drug and for the duration of the study
• Use of any other drugs, including over-the-counter medications and herbal preparations, within two weeks prior to first dose of study drug, unless approved/prescribed by the Principal Investigator as known not to interact with study drugs.
• Females of childbearing potential without the use of effective non-hormonal birth control methods, or not willing to continue practising these birth control methods for at least 30 days after the end of the treatment period
• Previous allergy to any of the constituents of the pharmaceuticals administered in this trial