Pharma & Specialty Chemical Standards

Cholecalciferol, IUPAC name (3S,5Z,7E,9E,11Z,13E,15Z,17R)-3,7,11,15-tetramethyl-9-(2-methylpropyl)-2,4,6,8,10,12,14,16-octadecaoctaene-1,18-diol, is a secosteroid with molecular formula C27H44O (molecular weight 384.64 g/mol). Structurally, it features a tetracyclic steroid nucleus with four methyl groups and a side chain containing conjugated double bonds. Therapeutically, it regulates calcium homeostasis, treating hypocalcemia, osteoporosis, and rickets. It is fat-soluble (logP ~5.5), hydrophobic, and stable under light. Mechanism involves hepatic and renal hydroxylation to calcitriol, which binds vitamin D receptors to enhance intestinal calcium/phosphate absorption and modulate bone remodeling. Its long hydrocarbon chain contributes to membrane permeability and slow systemic clearance.