Abdel-Fattah Laila, Abdel-Aziz Lobna, Gaied Mariam
Analytical Chemistry Department, Faculty of Pharmacy, Misr University for Science & Technology, Al-Motamayez District, P.O. Box 77, 6th of October City, Egypt.
Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Ain Shams University, Egypt.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Feb 5;136 Pt B:178-84. doi: 10.1016/j.saa.2014.09.007. Epub 2014 Sep 28.
In this study, a simple and sensitive spectrophotometric method was developed for determination of Losartan potassium (LST K), an angiotensin-II receptor (type AT1) antagonist, in presence of cationic surfactant cetyltrimethylammonium bromide (CTAB). The physicochemical interaction of LST K with CTAB was investigated. The effect of cationic micelles on the spectroscopic and acid-base properties of LST K was studied at pH 7.4. The binding constant (Kb) and the partition coefficient (Kx) of LST K-CTAB were 1.62×10(5) M(-1) and 1.38×10(5); respectively. The binding of LST K to CTAB micelles implied a shift in drug acidity constant (ΔpKa=0.422). The developed method is linear over the range 0.5-28 μg mL(-1). The accuracy was evaluated and was found to be 99.79±0.509% and the relative standard deviation for intraday and interday precision was 0.821 and 0.963; respectively. The method was successfully applied to determine LST K in pharmaceutical formulations.
在本研究中，开发了一种简单且灵敏的分光光度法，用于在阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）存在下测定血管紧张素II受体（AT1型）拮抗剂氯沙坦钾（LST K）。研究了LST K与CTAB的物理化学相互作用。在pH 7.4条件下，研究了阳离子胶束对LST K光谱和酸碱性质的影响。LST K - CTAB的结合常数（Kb）和分配系数（Kx）分别为1.62×10(5) M(-1)和1.38×10(5)。LST K与CTAB胶束的结合意味着药物酸度常数发生了变化（ΔpKa = 0.422）。所开发的方法在0.5 - 28 μg mL(-1)范围内呈线性。对准确度进行了评估，结果为99.79±0.509%，日内和日间精密度的相对标准偏差分别为0.821和0.963。该方法成功应用于药物制剂中LST K的测定。
