SUMMARY
There are a number of methods for determination of diclofenac sodium in medicines; however, they all differ by analytical methods involved depending on the drug dosage form. The aim of the study was to develop the universal HPLC-method for determination of diclofenac sodium, which would be suitable for quantitative determination of this active pharmaceutical ingredient (API) in various dosage forms. In our study a chromatograph 2695 with a photodiode array detector 2996 (Waters Corp., USA) and the column containing the C18 phase with the particle size of 5 mm, ER-182 balances (AND company, Japan), measuring glassware of class A were used. Validation of the method has been conducted in accordance with the requirements of the State Pharmacopoeia of Ukraine (SPhU). The HPLC-method for determination of diclofenac sodium in different drug dosage forms and UPLCvariant of this method for conducting rapid measurements have been developed. Validation of the methods proposed has been conducted, their suitability for determining diclofenac sodium in different drug dosage forms, as well as the insignificant effect of the sample preparation on the analysis results have been proven. The analysis of various medicines has been performed; the possibility of using the methods developed for the analysis of existing medicines based on diclofenac sodium has been proven.