Differential-pulse polarography (DPP) determination of betamethasone valerate in dosage form

The electrochemical reduction of betamethasone valerate (BV) in a pharmaceutical formulation containing neomycin has been carried out in Britton-Robinson buffer (BRB) (0.04 mol L-1) by differential-pulse polarography (DPP). BV exhibits a well-defined irreversible reduction peak at -1.03 V/ref. The influence of pH on the reduction of BV was studied in Britton-Robinson buffer (pH range 1.7-10). A method for the analysis of BV in BRB (0.04 mol L-1), which allows quantification over the range 3.9x10(-6)-1.1x10(-4) mol L-1, was proposed and successfully applied to the determination of BV in tablets with mean recovery and relative standard deviation of 100.81% and 0.45%, respectively.