The purpose of this study is to study the safety, tolerability and pharmacokinetics of rifabutin dosing with lopinavir/ritonavir tablets in healthy volunteers.

Inclusion Criteria:

• Adult Male or Female 18-55 yrs.
• Subject has provided written consent.
• Subject is in general good health.
• If female, subject is postmenopausal.
• If female, subject is not pregnant and is not breast-feeding.
• Subject must use birth control methods or be surgically sterile.

Exclusion Criteria:

• Subject is HAV-IgM, HBsAg or HIV Ab positive.
• Positive screen for drugs of abuse, alcohol, or smoking.
• Cannot be on any medication, including over the counter drugs.
• Cannot have previous history of alcohol or drug abuse.
• Cannot have history of any major diseases or disorders.