Intestinal transport mechanism and in vivo anticancer efficacy of a solid oral formulation incorporating an ion-pairing complex of pemetrexed with deoxycholic acid derivative

Abstract

Objective

The rational combination of immunotherapy with standard chemotherapy shows synergistic clinical activities in cancer treatment. In the present study, an oral powder formulation of pemetrexed (PMX) was developed to enhance intestinal membrane permeability and investigate its application in metronomic chemotherapy in combination with immunotherapy.

Methods

PMX was ionically complexed with a bile acid derivative (N^α-deoxycholyl-l-lysyl-methylester; DCK) as a permeation enhancer and mixed with dispersing agents, such as poloxamer 188 (P188) and Labrasol, to form an amorphous oral powder formulation of PMX/DCK (PMX/DCK-OP).

Results

The apparent permeability (P_app) of PMX/DCK-OP across a Caco-2 cell monolayer was 2.46- and 8.26-fold greater than that of PMX/DCK and free PMX, respectively, which may have been due to the specific interaction of DCK with bile acid transporters, as well as the alteration of membrane fluidity due to Labrasol and P188. Furthermore, inhibition of bile acid transporters by actinomycin D in Caco-2 cell monolayers decreased the P_app of PMX/DCK-OP by 75.4%, suggesting a predominant role of bile acid transporters in the intestinal absorption of PMX/DCK-OP. In addition, caveola/lipid raft-dependent endocytosis, macropinocytosis, passive diffusion, and paracellular transport mechanisms significantly influenced the permeation of PMX/DCK-OP through the intestinal membrane. Therefore, the oral bioavailability of PMX/DCK-OP in rats was 19.8%±6.93%, which was 294% higher than that of oral PMX. Moreover, an in vivo anticancer efficacy study in B16F10 cell-bearing mice treated with a combination of oral PMX/DCK-OP and intraperitoneal anti-PD1 exhibited significant suppression of tumor growth, and the tumor volume was maximally inhibited by 2.03- and 3.16-fold compared to the oral PMX/DCK-OP and control groups, respectively.

Conclusion

These findings indicated the therapeutic potential of a combination of low-dose oral chemotherapy and immunotherapy for synergistic anticancer efficacy.

Keywords:

• pemetrexed
• bile acid derivative
• oral powder formulation
• intestinal membrane permeability
• oral delivery
• oral metronomic chemotherapy

Supplementary material

Figure S1 In vitro cytotoxic effect of Act D on Caco-2 cells.

Notes: Cell viability was measured using WST-8 and the growth of Caco-2 cells compared to the untreated control group. All data are expressed as means ± standard deviation (n=6).

Abbreviation: Act D, actinomycin D.

Acknowledgment

This study was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) funded by the Korean Government Ministry of Science and ICT (MSIT; NRF-2017M3A9F5029656).

Disclosure

The authors report no conflicts of interest in relation to this work.