Tissue re-distribution of budesonide in rats co-administrated with curcumin by ultra performance liquid chromatography-tandem mass spectrometry.

Budesonide (BUD), a locally acting glucocorticoid with low side effects, is recommended in several Crohn's disease (CD) drug treatment guidelines as the first choice for early treatment. Nevertheless, the extensive first-pass effect mediated by P-glycoprotein (P-gp) and Cytochrome P450 3A4 (CYP3A4) leads to low bioavailability and limits further applications. Curcumin (CUR), a natural polyphenol derived from turmeric, has been found to influence the in vivo processes of drugs by affecting the activity of P-gp and CYP3A4. However, the pharmacokinetic interactions between BUD and CUR remains elusive, so an ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous determination of BUD and CUR in the tissue. The results showed that the area under the concentration-time curve 0 to time (AUC0→t) of BUD in the colon and kidney increased by approximately 32.35% and 39.03% respectively in the co-administered group compared to the single-drug group, while the small intestine, liver and plasma decreased by 80.03%, 67.34% and 24.34% respectively compared to the single-drug group. Therefore, long-term treatment with CUR can increase the concentration of BUD in the colonic area without increasing its systemic exposure, thus potentially reducing the incidence of side effects.