Dissolution Tests of Hydrochlorothiazide and Spironolactone in Commercial Tablets: Comparison of Spectroscopic and High Performance Liquid Chromatography Methods

Murat ŞÜKÜROĞLU*,^o, Figen TIRNAKSIZ**, Okan ATAY*
* Gazi University, Faculty of Pharmacy, Department of Pharmacautical Chemistry, Etiler - 06330 - Ankara

**Gazi University, Faculty of Pharmacy, Department of Pharmacautical Technology, Etiler - 06330 - Ankara

^oCorresponding Author

Summary

Two spectroscopic methods (absorbance ratio and Vierordt) were compared with high performance liquid chromatography (HPLC) for quantitative determination in dissolution tests of hydrochlorothiazide (HCT) and spironolactone (SPL) in commercial tablets. A 260 nm wavelength was chosen as the isosbestic point in the absorbance ratio method, and absorbance ratios of A₂₆₉/A₂₆₀ nm for HCT and A₂₄₂/A₂₆₀ nm for SPL were used for calculation of regression equations. For the Vierordt method, A₁¹ values (1%, 1 cm) calculated at 242 nm and 269 nm for both substances were used for quantitative analysis of HCT and SPL.
In the HPLC method, simultaneous determination of HCT and SPL from dissolution medium was achieved using the mobile phase containing water-methanol-phosphate buffer (71:25:4 v/v/v), pH: 3.1 + 0.1, in a Luna 5 um Cjg (250 x4.6 mm) reversed phase column. Mefruside was chosen as the internal standard and PDA detection was carried out at 286 nm (flow rate 0.7 mL.min^-1). Dissolution tests in commercial tablets were carried out according to USP XXVI paddle method in 0.1 N HCl containing 0.1% sodium lauryl sulfate at 75 rpm at 37 ± 0.5°C. Comparison of the dissolution data from the HPLC and two spectroscopic methods indicated that spectroscopic and HPLC methods snowed good correlation. Therefore, it was concluded that both spectroscopic method as well as HPLC can be used for routine analysis of HCT and SPL in dissolution tests of commercial tablets.

Key Words :
Hydrochlorothiazide-spironolactone, absorbance ratio, Vierordt, HPLC.