title: Determination of nimodipine in the presence of its degradation products and overall kinetics through a stability-indicating LC method.
abstract: The determination of nimodipine in the presence of its degradation products, formed through photolysis, acidic and alkaline hydrolysis, and the drug degradation kinetics under these conditions, was investigated through a validated liquid chromatography method. Separation was achieved using a Phenomenex Luna C18 column (250 × 4.6 mm i.d., 5 µm) with a mobile phase consisting of acetonitrile-methanol-water (55:11:34, v/v/v), at 0.5 mL/min and with ultraviolet detection at 235 nm. The method was considered to be specific, accurate, precise, robust and linear over the concentration range of 5.0 to 35.0 µg/mL. The drug followed a first-order reaction for both hydrolysis and photolysis in methanol, and zero-order for photolysis in acetonitrile and water. The calculated activation energies were 10.899 and 23.442 kcal/mol for alkaline and acidic hydrolysis, respectively. No degradation was observed under thermal and oxidative stress conditions.
authors.affiliation: Programa de Pós-Graduação em Farmácia, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-970, Brasil.
authors.forename: Manoela K
authors.initials: MK
authors.lastname: Riekes
authors.forename: Gabriela S
authors.initials: GS
authors.lastname: Rauber
authors.forename: Gislaine
authors.initials: G
authors.lastname: Kuminek
authors.forename: Monika P
authors.initials: MP
authors.lastname: Tagliari
authors.forename: Simone G
authors.initials: SG
authors.lastname: Cardoso
authors.forename: Hellen K
authors.initials: HK
authors.lastname: Stulzer
mesh_terms: D000704:Analysis of Variance; D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D006851:Hydrochloric Acid; D006868:Hydrolysis; D007700:Kinetics; D016014:Linear Models; D009553:Nimodipine / Q000032:analysis* / Q000737:chemistry; D010782:Photolysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012972:Sodium Hydroxide; D013696:Temperature
chemical_list: D012972:Sodium Hydroxide; D009553:Nimodipine; D006851:Hydrochloric Acid