Formulation and Pharmacokinetics of Thermosensitive Stealth® Liposomes Encapsulating 5-Fluorouracil - Inserm - Institut national de la santé et de la recherche médicale Access content directly
Journal Articles Pharmaceutical Research Year : 2015

Formulation and Pharmacokinetics of Thermosensitive Stealth® Liposomes Encapsulating 5-Fluorouracil


PURPOSE: We optimize the encapsulation and investigate the pharmacokinetics of 5-Fluorouracil (5-FU) delivered by thermosensitive stealth(®) liposomes (TSLs) designed to trigger drug release upon hyperthermia using focused ultrasound (FUS). METHODS: 5-FU was encapsulated into liposomes made of 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine/cholesterol/1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-PEG2000 either as a free molecule or complexed with copper-polyethylenimine. Heat-triggered drug release was evaluated using either a water bath or FUS. Formulation cytotoxicity was assessed on HT-29 cell line by MTS assay. Pharmacokinetics and biodistribution of 5-FU were evaluated in HT-29-tumor bearing mice. RESULTS: 5-FU was easily encapsulated using the lipid hydration method (encapsulation efficacy of 13%) but poorly retained upon dilution. 5-FU complexation with copper-polyethylenimine improved 5-FU retention into liposomes and allowed to obtain an encapsulation efficacy of 37%. At 42°C, heat-triggered 5-FU release from TSLs was 63% using a water bath and 68% using FUS, within 10 min, whereas it remained below 20% for the non-thermosensitive formulation. The MTS assay revealed that formulation toxicity arose from 5-FU and not from the excipients. In addition, 5-FU complex encapsulation into TSLs induces a reduction of the IC50 from 115 down to 49 μM. Pharmacokinetics reveals a longer circulation of encapsulated 5-FU and a more important body exposure, although tumor passive targeting is not significantly higher than free 5-FU. CONCLUSIONS: Complexation of 5-FU with copper-polyethylenimine appears an interesting strategy to improve 5-FU retention into TSLs in vitro and in vivo. TSLs allow heat-triggered release of the drug within 10 min at 42°C, a reasonable time for future in vivo experiments.
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Dates and versions

inserm-02438401 , version 1 (14-01-2020)



Chantal Al Sabbagh, Nicolas Tsapis, Anthony Novell, Patricia Calleja-Gonzalez, Jean-Michel Escoffre, et al.. Formulation and Pharmacokinetics of Thermosensitive Stealth® Liposomes Encapsulating 5-Fluorouracil. Pharmaceutical Research, 2015, 32 (5), pp.1585-1603. ⟨10.1007/s11095-014-1559-0⟩. ⟨inserm-02438401⟩
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