Optimisation and validation of a generic method for the LC assay of six corticosteroids and salicylic acid in dermopharmaceutical forms

Summary A generic method was developed for the liquid chromatographic (LC) assay of six corticosteraids and salicylic acid in different dermatological formulations containing methylparaben and propylparaben or sorbic acid as preservatives. An adequate separation was obtained using octadecylsilica as stationary phase and a mixture of acetonitrile (MeCN) and 25 mM phosphate buffer of pH 3.5 as mobile phase. Segmented gradient elution was applied from 30 to 45% of MeCN in 9.9 minutes, then from 45 to 96% in 19.0 minutes. UV detection was performed at 240 nm. The method was validated. Very good results were obtained with respect to linearity, selectivity, precision and accuracy.