Development and validation of kinetic and atomic absorption spectrophotometric methods for the determination of salbutamol sulfate

Abstract

Two sensitive kinetic and atomic absorption spectrophotometric (AAS) methods were developed for the determination of salbutamol sulfate (SLS) in its dosage forms. The kinetic method was based on the bromination reaction of the drug by bromine generated in situ by the reaction of bromate with bromide in acidic medium. The reaction was followed spectrophotometrically by measuring the decrease of bromine color at 380 nm. The reaction was carefully studied and optimized. Under optimum conditions, the stoichiometry and the order of the reaction were determined. The initial rate and fixed time methods were utilized for the determination of salbutamol sulfate concentrations. The AAS method depended on the oxidation of iron(II) with excess bromine from the bromination reaction of the drug. A new method for separation of iron(III) was used. Then iron(II) in the aqueous layer was aspirated into an air–acetylene flame and determined by AAS. The linear ranges for the proposed methods were 2.0–10.0 and 0.2–2.0 μg mL⁻¹ with detection limit of 0.30 and 0.012 μg mL⁻¹ for kinetic and AAS, respectively. The proposed methods were validated; the mean recovery ranges from 98.0 to 102.0% with RSD < 2.1%. Common excipients did not interfere with the measurements of SLS. The methods were successfully applied to determine SLS in dosage forms; there was no significant difference between the proposed methods and official one.