Figure 1.

Effects of (a) pre-incubating CEM, CEM_E1000 (E1000) and CEM_VBL (VBL) cells with various concentrations (0–30 µM) of unlabelled lopinavir (LPV) followed by the addition of [¹⁴C]LPV and (b) co-incubating the cells with [¹⁴C]LPV followed by the addition of various concentrations (0–30 µM) of unlabelled LPV on the accumulation of [¹⁴C]LPV. Bars indicate mean ± SD (n = 4, with four independent observations from cultured CEM and its variant cells). Results are expressed as the CAR, being the ratio of the amount of [¹⁴C]LPV associated with the cell pellets to the amount in a similar volume of medium after incubation. P values of *P < 0.05, **P < 0.01 and ***P < 0.001 indicate statistically significant differences in the CAR of [¹⁴C]LPV between control and drug-treated samples.