Application of HPLC-DAD and spectrophotometric continuous wavelet transform methods for simultaneous determination of amoxicillin and diclofenac in their pure and capsule dosage forms

Abstract

Two methods have been developed and validated for simultaneous determination of amoxicillin sodium and diclofenac sodium in their pure and combined pharmaceutical dosage forms. The first method was HPLC-DAD; the chromatographic separation and resolution has been carried out using a reversed phase BDS Hypersil C18 column with a mobile phase consisting of methanol : acetonitrile : water : orthophosphoric acid (60 : 30 : 9 : 1 by volume), at a flow rate of 1 mL minute⁻¹ and UV detection at 250 nm. The retention times were found to be 3.906 and 6.997 minutes for amoxicillin and diclofenac respectively. The second method was continuous wavelet transform (CWT), which is based on derivative calculation of spectrophotometric spectral data of both drugs in their binary mixture, and the zero crossing point for amoxicillin and diclofenac was found to be at 233 and 247 nm, respectively. The results obtained were statistically compared to reference methods and there were no significant differences between the proposed methods and the reference methods regarding the accuracy and precision. The method was validated according to ICH guidelines and the results were satisfactory.