Polarographic behaviour and determination of beclomethasone dipropionate

The polarographic behaviour of beclomethasone dipropionate in Britton-Robinson buffers containing 40% methanol as a solubilizer has been studied. Over the pH range 1.8–12, a cathodic wave was produced, which was characterised as being irreversible, diffusion controlled and free from adsorption phenomena. The number of electrons involved in the reduction was found through comparative study with spironolactone. Using direct current polarographic mode, the limiting current concentration plot is rectilinear over the range 2.5 × 10^–5 to 4 × 10^–4 mol/1 with a detection limit of 2.5 × 10^–6 mol/1. A method has been developed for the determination of the drug in aerosols and creams, the results being in agreement with those obtained by the official method.