Abstract

A simple, inexpensive, environmentally friendly, sensitive, and selective spectrophotometric method was developed for the determination of salbutamol sulfate (SAL) in its pure form and in pharmaceutical preparations. The method is based on the chlorination reaction of salbutamol sulfate using sodium hypochlorite to form a chloro-derivative of SAL and the excess (unreacted) sodium hypochlorite was subsequently removed by treatment with nitrite ion. The color development occurs through the oxidation of iodide by the chloro-derivative of SAL to iodine in the presence of starch, which leads to form a blue colored product, and its absorbance was measured at 568 nm. Under the optimized reaction condition, a linear relationship was obtained over the concentration range of 1-17 µg mL⁻¹ and obeyed Beer’s law with a determination coefficient (R²) = 0.9992. The molar absorptivity and Sandell’s sensitivity were found to be 2.81×10⁴ L mol-1 cm⁻¹ and 2.05 ×10⁻² µg cm-2, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were 0.113 µg mL⁻¹ and 0.379 µg mL⁻¹, respectively. The proposed method was successfully applied for the determination of SAL in pure form and in various pharmaceutical preparations, including tablets, syrups, and inhalation solution, yielding satisfactory recovery percentages ranging from 98.9 % to 100.4 % and without interference from common excipients, thus confirming the possibility of adopting this method in routine analytical laboratories.

Keywords: salbutamol sulfate (SAL), sodium hypochlorite, starch, chlorination reaction, spectrophotometry

Article language: En