Effects Of Simotinib Hydrochloride On The Ansmembrane Transport Of Intestinal Epithelial Cells

Aim:To study the effects and mechanism of simotinib hydrochloride on the transmembrane transport of intestinal epithelial cells, and explore the reason of its gastrointestinal toxicity. Thus provide guidance for clinical administration of simotinib hydrochloride and also provide the basis for better formulation of EGFR-TKIs to alleviate adverse gastrointestinal effects.Methods:Rats pharmacokinetic model was used to study the effects of simotinib hydrochloride on transmembrane transport. The intestinal passive transmembrane transport was measured by in situ loop assay and Caco-2cell transwell model. Validated HPLC-UV methods were developed to determine the concentrations of the drugs. Real-time PCR and Western blots were applied to detecting the expression changes of cell junction genes. The pharmacokinetic parameters were calculated by WinNonlin6.1and data were analyzed using the statistical software SPSS13.0.Results:The pharmacokinetic studies demonstrated that multiple dosage administration of simotinib hydrochloride reduced the rat body weights by decreasing food intake. The exposure of PepTl substrate cefaclor, valaciclovir and non-substrate acyclovir were significantly upregulated when administrated in combination in rats. Caco-2cell transwell model and in situ loop assay showed simotinib hydrochloride increased the permeability of fluorescein which was used as a paracellular transport marker, but the permeability of passive transcellular marker propranolol was not increased. The low mRNA and protein expression of cell junction gene afadin was observed in Caco-2cells and small intestine of rats after simotinib hydrochloride treatment in real-time PCR and Western blots assay.Conclusion:Simotinib hydrochloride upregulated the intestinal non-selective absorption and increased the exposure of drugs in combination by significantly lowering the expression of cell junction gene Afadin and increasing the paracellular but not the passive transcellular permeability of intestinal epithelial cells. Thus, in clinic the dosage of other drugs should be adjusted when in combination with simotinib hydrochloride to avoid the risk of drug-drug interactions.