Objective To investigate biological transport of minocycline by human periodontal ligament fibroblasts（HPDLF）. To verify the hypothesis of delivering medicine to periodontium and the whole body through the root canal. Methods HPDLF and MC3T3- E1 cells were incubated in minocycline solutions. The intracellular antibiotics contents were measured by high performance liquid chromatography（HPLC） and the cell total protein was measured by Bradford protein assay. Results HPLC was an accurate, sensitive method for measurement of the intracellular minocycline. The incubation time and cell property had significant effect on the intracellular minocycline contens（P
