Development of a single-tube, low-cost, analytical process to extract, separate and determine efavirenz and rifampicin plasma concentrations in HIV/TB co-infected patients

Background Tuberculosis (TB) complicating HIV-1 infection is a persistent significant clinical concern, particularly in resource limited settings. Treatment of HIV-infected patients with TB often comprises efavirenz-containing antiretroviral regimens particularly when on TB treatment containing rifampicin. Although rifampicin may reduce EFV concentrations, little is known of the effect of the HIV virus or efavirenz on the pharmacokinetics of rifampicin, particularly in resource limited settings where the burden of disease exists. We aimed to develop a low-cost, simple analytical method for the accurate determination of efavirenz and rifampicin plasma concentrations.