(1S)-Calcitriol (1α,25-Dihydroxy-3-epi-vitamin-D3) is a natural metabolite of 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3). (1S)-Calcitriol exhibits potent vitamin D receptor (VDR)-mediated actions such as inhibition of keratinocyte growth or suppression of parathyroid hormone secretion[1]. 3‐epi‐Calcitroic acid is an end product of (1S)-Calcitriol (1α,25-Dihydroxy-3-epi-vitamin-D3; 3‐epi‐1a,25(OH)2D3) metabolism by rat CYP24A1[1]. [1]. Steve Y Rhieu, et al. Metabolic stability of 3-epi-1α,25-dihydroxyvitamin D3 over 1 α 25-dihydroxyvitamin D3: metabolism and moleculardocking studies using rat CYP24A1. J Cell Biochem. 2013 Oct;114(10):2293-305.
Celecoxib carboxylic acid is an inactive metabolite of the COX-2 inhibitor celecoxib .1,2It is formed from celecoxib primarily by the cytochrome P450 (CYP) isoform CYP2C9. 1.Liu, H., Huang, X., Shen, J., et al.Inhibitory mode of 1,5-diarylpyrazole derivatives against cyclooxygenase-2 and cyclooxygenase-1: Moleculardocking and 3D QSAR analysesJ. Med. Chem.45(22)4816-4827(2002) 2.Kim, S.-H., Kim, D.-H., Byeon, J.-Y., et al.Effects of CYP2C9 genetic polymorphisms on the pharmacokinetics of celecoxib and its carboxylic acid metaboliteArch. Pharm. Res.40(3)382-390(2017)