title: Thermal analysis applied to verapamil hydrochloride characterization in pharmaceutical formulations.
abstract: Thermogravimetry (TG) and differential scanning calorimetry (DSC) are useful techniques that have been successfully applied in the pharmaceutical industry to reveal important information regarding the physicochemical properties of drug and excipient molecules such as polymorphism, stability, purity, formulation compatibility among others. Verapamil hydrochloride shows thermal stability up to 180 degrees C and melts at 146 degrees C, followed by total degradation. The drug is compatible with all the excipients evaluated. The drug showed degradation when subjected to oxidizing conditions, suggesting that the degradation product is 3,4-dimethoxybenzoic acid derived from alkyl side chain oxidation. Verapamil hydrochloride does not present the phenomenon of polymorphism under the conditions evaluated. Assessing the drug degradation kinetics, the drug had a shelf life (t90) of 56.7 years and a pharmaceutical formulation showed t90 of 6.8 years showing their high stability.
authors.affiliation: Departamento de Química, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, Belo Horizonte, MG, Brazil.
authors.forename: Maria Irene
authors.initials: MI
authors.lastname: Yoshida
authors.forename: Elionai Cassiana Lima
authors.initials: EC
authors.lastname: Gomes
authors.forename: Cristina Duarte Vianna
authors.initials: CD
authors.lastname: Soares
authors.forename: Alexandre Frinhani
authors.initials: AF
authors.lastname: Cunha
authors.forename: Marcelo Antonio
authors.initials: MA
authors.lastname: Oliveira
mesh_terms: D002121:Calcium Channel Blockers / Q000032:analysis / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002853:Chromatography, Liquid; D004355:Drug Stability; D005079:Excipients / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D044366:Transition Temperature; D014700:Verapamil / Q000032:analysis / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D002121:Calcium Channel Blockers; D005079:Excipients; D014700:Verapamil