Detection of Lamivudine and Emtricitabine in Urine using a Modified Pyrimidine Assay

Abstract

Monitoring the adherence of patients taking highly-active anti-retroviral therapy (HAART) and Pre-Exposure Prophylaxis (PrEP) is a key step in treating an HIV infection. Since current monitor methods are non-direct there is a need for assays that directly verify the presence of active drug in the patient. In this work we modified an existing assay for the detection of cytosine to sense the presence of lamivudine (3TC) in spiked urine and emtricitabine (FTC) in water. 3TC and FTC is reacted with bromine and barium hydroxide to generate a colored precipitate in less than an hour indicating the presence of active drug. The current detection limit of the 3TC assay is 870uM in water and 2mM in urine. This assay can be applied in clinics to monitor patient adherence without the need for expensive equipment such as HPLC.