VOLTAMMETRIC STUDY OF SALBUTAMOL AND APPLICATION TO ITS DETERMINATIONIN A TABLET DOSAGE FORM AND DISSOLUTION PROFILES FOR THE DOSAGE FORM

The oxidative voltammetric behaviour of salbutamol at a glassy carbon electrode surface has been studied using cyclic voltammetry and differ ential pulse voltammetry. Oxidation of the drug was effected in a sing le irreversible, adsorption-controlled step in phosphate buffer. The p rocess was found to be dependent on the ionic strength and the pH of t he supporting electrolyte. The response was evaluated with respect to accumulation time, scan rate and other variables. Using differential p ulse voltammetry following electrochemical pretreatment of the electro de surface, the drug yielded a well-defined voltammetric response in p hosphate buffer, pH 5.0, at +0.75 V (vs SCE). This process could be us ed to determine salbutamol concentrations in the range 8 x 10(-7) M to 8 x 10(-5) M with a detection limit of 2 x 10(-7) M. The method was a pplied, without any interferences from the excipients, to the determin ation of the drug in a tablet dosage form and in drug dissolution stud ies. The absolute recovery for salbutamol was greater than 95% at the concentration levels studied, and reproducible voltammetric signals we re obtained with a relative standard deviation of 2.4% for n = 7 at a concentration level of 8 x 10(-5) M.