PMC

Chromatograms for ZDV (top) and 3TC (middle) obtained from an HIV-infected individual. The solution was processed throughout the complete procedure, and AZdU was used as the internal standard (bottom). Retention times for ZDV, 3TC, and AZdU were 3.08, 3.41, and 2.72 min, respectively. Chromatographic conditions are described in Materials and Methods. The y axis is the ion intensity obtained for each compound.

Calibration standard curve for 3TC-TP constructed from standard solutions (4, 21, 43, 85, and 128 pmol) and passed through the complete methodology. The data plotted represent the average of two determinations for each concentration. Error bars reside within the points if not shown. The equation describing the complete range is y = 0.121x − 0.018, with a regression coefficient (r) of 0.998.

Intracellular pharmacokinetic profile for 3TC-TP (top) and ZDV-TP (bottom) from five HIV-infected patients. Patients stayed overnight at the University of Puerto Rico-Clinical Research Center facilities, and samples were collected at predose (time zero) and 1, 2, 4, 8, 12, 16, and 24 h postdose. The line represents the median value for each time point.