Chromatographic Application on a Calixarene Stationary Phase: A Novel HPLC Determination of Flumethasone Pivalate and Salicylic Acid in Their Binary Mixture and Ointment Dosage Form after Two Steps Extraction
Present study reported for the first time about a new, simple, fast, robust and accurate, routine HPLC method for simultaneous quantification of Flumethasone Pivalate and salicylic acid in bulk powder and in an ointment dosage form. Chromatographic analysis was carried out on Calixarene stationary phase after two steps extraction. Water was used in first step for extraction of salicylic acid because the excipients in the ointment interfere with salicylic acid determination upon extraction with organic solvent. After that the residue was extracted with organic solvent for Flumethasone Pivalate. Acetonitrile and H2O in the ratio of 70:30 at flow rate of 1 mLmin 1 and 40 degC were applied as isocratic binary mobile phase. Detection was done at 240 nm. Limits of detection and quantitation for both analytes were 0.125 and 0.250 ug mL 1 respectively. The recovery values of this method were 98.99 0.66% and 97.50 1.33% for salicylic acid and Flumethasone Pivalate, respectively. The effect of small variations in temperature, flow rate, detection wavelength, acetonitrile percentage in mobile phase and injection volume was studied to determine the robustness of the method. The proposed method was found to be robust.