Impurities in Drugs II: Meperidine and Its Formulations

Abstract Three lots of meperidine hydrochloride, seven lots of meperidine tablets, and 41 lots of meperidine injectables were examined for impurities by TLC. Impurities found were ethyl 1-benzyl-4-phenyl-4-piperidinecarboxylate, methyl l-methyl-4-phenyl-4-piperidinecarboxylate, ethyl l-ethyl-4-phenyl-4-piperidinecarboxylatea,n d three unidentified compounds. Not all impurities were found in every lot of drug investigated, and none of the impurities exceeded a concentration of 1% of the meperidine present.