Determination of pKa values of some antihypertensive drugs by liquid chromatography and simultaneous assay of lercanidipine and enalapril in their binary mixtures
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Tarih
2010
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier B.V.
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
In this study, pKa values were determined using the dependence of the retention factor on the pH of the mobile phase for three ionizable substances, namely, enalapril, lercanidipine and ramipril (IS). The effect of the mobile phase composition on the ionization constant was studied by measuring the pKa at different methanol-water mixtures, ranging between 50 and 65% (v/v), using LC-DAD method. Two simple, accurate, precise and fully validated analytical methods for the simultaneous determination of enalapril and lercanidipine in combined dosage forms have been developed. Separation was performed on an X-Terra RP-18 column (250 mm × 4.60 mm ID × 5 ?m) at 40 °C with the mobile phase of methanol-water 55:45 (v/v) adjusted to pH 2.7 with 15 mM orthophosphoric acid. Isocratic elution was performed in less than 12 min with a flow rate of 1.2 mL min-1. Good sensitivity for the analytes was observed with DAD detection. The LC method allowed quantitation over the 0.50-20.00 ?g mL-1 range for enalapril and lercanidipine. The second method depends on first derivative of the ratio-spectra by measurements of the amplitudes at 219.7 nm for enalapril and 233.0 nm for lercanidipine. Calibration graphs were established for 1-20 ?g mL-1 for enalapril and 1-16 ?g mL-1 lercanidipine, using first derivative of the ratio spectrophotometric method. Both methods have been extensively validated. These methods allow a number of cost and time saving benefits. The described methods can be readily utilized for analysis of pharmaceutical formulations. The methods have been applied, without any interference from excipients, for the simultaneous determination of these compounds in tablets. There was no significant difference between the performance of the proposed methods regarding the mean values and standard deviations. © 2010 Elsevier B.V. All rights reserved.
Açıklama
Anahtar Kelimeler
Determination, Enalapril, Lercanidipine, Liquid Chromatography, Ramipril
Kaynak
Talanta
WoS Q Değeri
N/A
Scopus Q Değeri
Q1
Cilt
82
Sayı
4
Künye
Gumustas, M., Şanlı, S., Şanlı, N., & Ozkan, S. A. (2010). Determination of pKa values of some antihypertensive drugs by liquid chromatography and simultaneous assay of lercanidipine and enalapril in their binary mixtures. Talanta, 82(4), 1528-1537.
