ENZYMATIC ASSAY OF SALBUTAMOL IN BULK AND TABLET DOSAGE FORMS

Abstract

Enzymatic methods for determining compounds are a key technology in quantification of various analytes of chemical and biochemical interests have found wide range of applications in clinical diagnosis, medical treatment, biochemical research and industrial purposes because of their high specificity and rapidity. The present work is an attempt to develop three novel spectrophotometric methods for the determination of salbutamol in bulk and in its pharmaceutical dosage forms. The proposed methods are based on the oxidative coupling of salbutamol with 3-Methylbenzothiazoline-2-one hydrazone (method M1), Aniline (method M2) and 4 – Aminoantipyrine (method M3) in the presence of hydrogen peroxide and horseradish peroxidase to produce a colored complex having absorption maxima at 450 nm, 480 nm and 490 nm, respectively. The reaction conditions were optimized to obtain maximum color intensity. The absorbance was found to increase linearly with increasing the concentration of salbutamol; the systems obeyed the Beer’s law in the range 2–12 $\mu$g/ml for methods M1 & M2 and 5–30 $\mu$g/ml for method M3. The correlation coefficient values were found to be 0.9985 (M1) and 0.9987 (M2 & M3). Sandell's sensitivity is calculated as 0.02247, 0.00943 and 0.04950 $\mu$g/cm²/0.001 abs. unit for methods M1, M2 and M3, respectively. Results of analysis of these methods were validated statistically and by recovery studies. The method is applied to the marketed tablet formulation. The percentage relative standard deviations are 0.568-0.884, 0.493-0.713 and 0.503-0.692 for methods M1, M2 and M3, respectively. The accuracy was examined by performing recovery studies and was found to be 97.25-

• (M1), 99.0-101.25 (M2) and 97.50-102.25 (M3). No interference was observed from common excipients present in pharmaceutical formulations. The developed methods are simple, sensitive and reproducible and can be used for routine analysis of salbutamol in bulk and tablet dosage