Simultaneous determination of enalapril, felodipine and their degradation products in the dosage formulation by reversed-phase high-performance liquid chromatography using a Spherisorb C8 column
1995; Elsevier BV; Volume: 707; Issue: 2 Linguagem: Inglês
10.1016/0021-9673(95)00349-r
ISSN1873-3778
AutoresXue‐Zhi Qin, Joe DeMarco, Dominic P. Ip,
Tópico(s)Antibiotics Pharmacokinetics and Efficacy
ResumoA reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the simultaneous determination of enalapril and its two degradation products, enalaprilat (diacid, hydrolytic degradation product of enalapril) and enalapril-DKP (cyclization of enalapril); and felodipine and its degradation product, H152/37 (oxidation of felodipine) in the combined enalapril/felodipine (5 mg/5 mg) formulation. Using a Spherisorb C8 column with a CH3CN-0.001 M KH2PO4 (pH 2) (35:65, v/v) mobile phase, these compounds were well separated from each other, and also from maleic acid and the excipients in the formulation. The method was demonstrated to be precise, accurate, specific and robust. Optimization of the separation in terms of mobile phase composition is crucial to the method development, which is discussed in detail. It is proposed that under the experimental conditions used, the retention of felodipine, DKP and H152/37 is governed by the reversed-phase partitioning process whereas that of enalapril and diacid is governed by both the partitioning and the cation-exchange process with residual silanols.
Referência(s)