title: Enhanced spectrophotometric determination of Losartan potassium based on its physicochemical interaction with cationic surfactant.
abstract: 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.
authors.affiliation: Analytical Chemistry Department, Faculty of Pharmacy, Misr University for Science & Technology, Al-Motamayez District, P.O. Box 77, 6th of October City, Egypt.
authors.forename: Laila
authors.initials: L
authors.lastname: Abdel-Fattah
authors.affiliation: Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Ain Shams University, Egypt. Electronic address: Lobna.analytical@yahoo.com.
authors.forename: Lobna
authors.initials: L
authors.lastname: Abdel-Aziz
authors.affiliation: Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Ain Shams University, Egypt.
authors.forename: Mariam
authors.initials: M
authors.lastname: Gaied
mesh_terms: D002138:Calibration; D002412:Cations; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D055598:Chemical Phenomena; D019808:Losartan / Q000032:analysis* / Q000737:chemistry*; D008823:Micelles; D013053:Spectrophotometry / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet; D013501:Surface-Active Agents / Q000737:chemistry*; D013607:Tablets
chemical_list: D002412:Cations; D002593:Cetrimonium Compounds; D008823:Micelles; D013501:Surface-Active Agents; D013607:Tablets; D019808:Losartan; D000077286:Cetrimonium
keywords: Binding; CTAB; Losartan potassium; Partition coefficient; Spectrophotometric determination