STATISTICAL OPTIMIZATION OF A REVERSED-PHASE LIQUID-CHROMATOGRAPHIC METHOD FOR THE DETERMINATION OF AMILORIDE AND METHYCLOTHIAZIDE IN TABLETS

A quantitative high-performance liquid chromatographic method in which amiloride is separated from methyclothiazide on a C-18 column with de tection al 286 nm was developed with the aid of the 'window diagram' t echnique of Laub and Purnell. The effect of simultaneously varying the pH and methanol to water ratio in the mobile phase were studied to op timize the separation. The method was applied to the quantitative anal ysis of Lometazid tablets. The powdered tablets were extracted with me thanol, containing phenacetin as the internal standard, and assayed by comparison of peak heights after liquid chromatography.