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Updated: May 14, 2026

Preparation, Administration, and Assessment of In Vivo Tissue-Specific Cellular Uptake of Fluorescent Dye-Labeled Liposomes
Published on: July 30, 2020
[Cellular uptake of TPS-L-carnitine synthesised as transporter-based renal targeting prodrug]
1Department of Pharmacy, West China Hospital, Sichuan University, Chengdu 610041, China.
Objective:
To synthesize transporter-based renal targeting prodrug TPS-L-Carnitine and to determine its cellular uptake in vitro.
Methods:
Triptolide (TP) was conjugated with L-carnitine using succinate as the linker to form TPS-L-Carnitine, which could be specifically recognized by OCTN2, a cationic transporter with high affinity to L-Carnitine and is highly expressed on the apical membrane of renal proximal tubule cells. Cellular uptake assays of the prodrug and its parent drug were performed on HK-2 cells, a human proximal tubule cell line, in different temperature, concentration and in the presence of competitive inhibitors.
Results:
TPS-L-Carnitine was taken up into HK-2 cells in a saturable and temperature- and concentration-dependent manner. The uptake process could be inhibited by the competitive inhibitors. The uptake of TPS-L-Carnitine was significantly higher than that of TP at 37 degrees C in the same drug concentration. TPS-L-Carnitine was taken through endocytosis mediated by transporter.
Conclusion:
TPS-L-Carnitine provides a good renal targeting property and lays the foundation for further studies in vivo.
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