Selected aspects of the Analytical Chemistry of Amlodipine, a widely used long acting Calcium antagonist

Abstract

Amlodipine is a poly-substituted 1,4-dihydropyridine with activity as a calcium antagonist. The drug inhibits the transmembrane influx of calcium ions into vascular smooth muscles and cardiac muscles; therefore, it is prescribed in the treatment of hypertension and angina pectoris. Amlodipine, which is official in all the recognized pharmacopeias, has been in clinical use during the last 30 years. The drug is currently available as the besylate and to a lesser extent, as the maleate salt.Discussed in this article is the analytical chemistry of amlodipine, from the perspective of the modern concepts of drug purity control and the need of stability indicating assays for quality assurance purposes. Hence, the synthesis and stability of the heterocycle, as well as the preparation of impurities and their determination in different scenarios are presented. Other specific aspects such as phase transitions, as well as the determination of genotoxic impurities, the enantiomers of the drug and compounds resulting from compatibility with excipients and other substances, are also discussed.