Lipophilic prodrug of paclitaxel: interaction with a dimyristoylphosphatidylcholine monolayer.

Interactions between paclitaxel and its squalenoyl prodrug with dimyristoylphosphatidylcholine (DMPC) monolayer at the air/water interface were studied. Paclitaxel is an antineoplastic drug, largely used as anti-cancer agents. Because its low aqueous solubility, Cremophor EL is used as excipient for its formulation. However, it has been shown that Cremophor causes serious side effects. Several attempts have been made to develop a safer formulation such as the synthesis of lipophilic prodrug. In particular we have synthesized a paclitaxel prodrug obtained by conjugation with 1,1,2-trisnorsqualenoic acid to improve the physico-chemical properties of this antineoplastic drug. The miscibility of these compounds with DMPC monolayer were studied analyzing thermodynamic properties as well as excess Gibbs free energies, compressibility modulus and mixed monolayer isotherms. The results allowed to evaluate the spatial organization of the compounds and suggested that the prodrug can efficiently be incorporated in the DMPC monolayer.