Related Experiment Video
Updated: Apr 22, 2026

Extraction and Characterization of Surfactants from Atmospheric Aerosols
Published on: April 21, 2017
Enhanced spectrophotometric determination of Losartan potassium based on its physicochemical interaction with
Laila Abdel-Fattah1, Lobna Abdel-Aziz2, Mariam Gaied2
1Analytical Chemistry Department, Faculty of Pharmacy, Misr University for Science & Technology, Al-Motamayez District, P.O. Box 77, 6th of October City, Egypt.
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.
Related Concept Videos
Surface Active Agents
Factors Affecting Dissolution: Drug pKa, Lipophilicity and GI pH
A drug's pKa and the pH of the gastrointestinal (GI) tract play crucial roles...
Factors Influencing Drug Absorption: Physicochemical Parameters
Enhanced drug absorption can be achieved by reducing particle sizes and increasing surface areas, thereby facilitating...
Bioavailability Enhancement: Drug Solubility Enhancement
Protein-Drug Binding: Determination Methods
Indirect methods involve isolating the bound drug from its free form in biological samples such as blood, serum, or plasma. These techniques aim to measure the percentage of drugs bound to proteins. Equilibrium dialysis is a commonly used method where the free drug concentration at equilibrium is measured by separating the bound...
Dose-Response Relationship: Potency and Efficacy

