Table 1.
Kinetic Constantsa for Clarithromycin Transport by SCC-25 Cells and Gingival Fibroblasts
Cell type | Km (μg/ml) | Vmax (μg/min/106) | Cellular/Extracellular concentration ratio |
---|---|---|---|
SCC-25 cell line | 227 ± 20 b | 381 ± 29.5 b | 3.3 ± 0.28 c |
gingival fibroblasts | 78.4 ± 7.2 b | 264 ± 32.1 b | 37.9 ± 2.6 c |
Km (Michaelis constant) and Vmax (maximum transport velocity) were determined by Lineweaver-Burk analysis of transport activity assayed in the presence of several different concentrations of clarithromycin (8 to 50 μg/ml) during the rapid initial phase of uptake (first 3 minutes). The Cellular/Extracellular concentration ratio was determined in medium containing 2 μg/ml clarithromycin. The data represent the mean ± SEM of four experiments with SCC-25 cells and three experiments with gingival fibroblasts.
Values within columns are significantly different (P < 0.05, t-test)
Values within columns are significantly different (P < 0.05, Mann-Whitney rank sum test)