Enhancing Oral Performance of Paclitaxel Lipid-Mimic Prodrug via Modulating Type of Fatty Acids.

Owing to the serious clinical side effects of intravenous Taxol, an oral chemotherapeutic strategy is expected to be promising for paclitaxel (PTX) delivery. However, its poor solubility and permeability, high first-pass metabolism, and gastrointestinal toxicity need to be overcome. A triglyceride (TG)-like prodrug strategy facilitates oral drug delivery by bypassing liver metabolism. However, the effect of fatty acids (FAs) in sn-1,3 on the oral absorption of prodrugs remains unclear. Herein, a series of TG-mimetic prodrugs of PTX is explored with different carbon chain lengths and degrees of unsaturation of FAs at the sn-1,3 position in an attempt to enhance oral antitumor effect and to guide the design of TG-like prodrugs. Interestingly, the different FA lengths exhibit great influence on in vitro intestinal digestion behavior, lymph transport efficiency, and up to fourfold differences in plasma pharmacokinetics. The prodrug with long-chain FAs shows a more effective antitumor effect, whereas the degree of unsaturation has a negligible impact. The findings illustrate how FAs structures affect the oral delivery efficiency of TG-like PTX prodrugs and thus provide a theoretical basis for their rational design.

Long chain triglyceride-lipid formulation promotes the oral absorption of the lipidic prodrugs through coincident intestinal behaviors.

Oral administration of chemotherapy agents, such as docetaxel (DTX), is expected to reduce side effects significantly and increase dosing frequency. However, they often suffer from poor oral bioavailability, impeding their oral application. Dietary lipids such as triglycerides favor lymphatic transport nor vein system, bypassing the first-pass metabolism. Inspired by this concept, we developed a triglyceride-like prodrug of DTX (named as OATG) and explored the effect of lipid types on the OATG oral delivery. The plasma profile in rats revealed that long chain triglyceride (LCT)-based lipid formulations (LBLF) were more promising for OATG delivery than medium chain triglyceride (MCT) ones. The OATG LBLF elicited a markedly enhanced absorption compared with oral Taxotere or DTX LBLF, resulting in relative bioavailability 6.11 or 2.47-fold higher, respectively. The coincident intestinal behaviors of lipid excipients and TG-like prodrug facilitate the oral absorption of the prodrug. The effectiveness of the prodrug formulation was also examined in beagles with absolute bioavailability up to 41.08%, in sharp contrast to that of control DTX group (8%). Besides, the OATG oral formulation could be schedule-intensively administrated with no hypersensitivity, gastrointestinal and hematological toxicity. The current strategy provides an effective lipid formulation and a promising chance for chemotherapy at home.

Probing the new strategy for the oral formulations of taxanes: changing the method with the situation.

The first-generation taxanes (including paclitaxel and docetaxel) are widely used for the treatment of various cancers in clinical settings. In the past decade, a series of new-generation taxanes have been developed which are effective in the inhibition of tumor resistance. However, intravenous (i.v.) infusion is still the only route of administration, and may result in serious adverse reactions with respect to the utilization of Cremophor EL or Tween-80 as solvent. Besides, the dosing schedule is also limited. Therefore, oral administration of taxanes is urgently needed to avoid the adverse reactionss and increase dosing frequency. In this review, we first outlined the discovery and development of taxane-based anticancer agents. Furthermore, we summarized the research progress on the oral formulations of taxanes and proposed some thoughts on the future development of oral taxane formulations.