Separation of phosphorylated nucleoside reverse transcriptase inhibitors by capillary electrophoresis

Capillary electrophoretic (CE) conditions were established to separate multiple nucleoside reverse transcriptase inhibitor triphosphates (NRTI-TPs). These are the active drug forms of nucleoside reverse transcriptase inhibitors (NRTIs) used to treat HIV-infected patients and two NRTIs are always used as part of a three or four drug regimen. Two buffer systems were suitable to separate multiple NRTI-TPs using CE. A carbonate/borate buffer under a positive applied voltage provided for the separation of six different NRTI-TPs of interest. A phosphate buffer, however, under suppressed electroosmotic flow conditions (i.e., low pH) and a negative applied voltage proved to be more effective than the carbonate/borate system. Addition of EDTA to the run buffer improved resolution and overall peak shape of the NRTI-TP. The established experimental conditions can be used to separate multiple NRTI-TPs in peripheral blood mononuclear cells (PBMCs) from human whole blood.