Pharma & Specialty Chemical Standards

Cycloserine, IUPAC name (2R,4R)-4-amino-2-hydroxy cyclopentane carboxylic acid, is a cyclic amino acid derivative with molecular formula C5H9NO3 (molecular weight 131.13 g/mol). Structurally, it features a five-membered ring containing hydroxyl and amino groups, classifying it as a D-alanine analog. It is a second-line antitubercular agent, effective against multidrug-resistant Mycobacterium tuberculosis. Cycloserine exhibits moderate water solubility and a pKa of ~2.5. Its mechanism involves competitive inhibition of alanine racemase and D-alanyl-D-alanine ligase, disrupting bacterial cell wall peptidoglycan synthesis. Key physicochemical properties include a melting point of 200–205°C and amphoteric behavior due to ionizable carboxyl and amino groups.