Triamterene Potassium compounds

Triamterene (31) is a diuretic that has found acceptance because it results in enhanced sodium ion excretion without serious loss of potassium ion or significant uric acid retention. Tautomerism of aminopyrimidines (e.g., 27a and 27b) serves to make the "nonenolized" amine at the 5 position more basic than the remaining amines. Thus, condensation of 27 with benzaldehyde goes at the most basic nitrogen to form 28. Addition of hydrogen cyanide gives the a-aminonitrile (29). Treatment of that intermediate with base leads to the eyelized dihydropirazine compound (30). This undergoes spontaneous air oxidation to afford triamterene (31). ... 

An interesting new development has been the discovery that certain pteridine compounds promote sodium excretion and, at the same time, potassium retention. Clinical studies in hypertensive patients carried out with triamterene indicated that the drug was not in itself sufficiently potent as a natriuretic agent in hypertensive patients to be clinically useful (10). When combined with half-strength doses of hydrochlorothiazide, however, its natriuretic effect was comparable to that obtained with full doses of hydrochlorothiazide but without significant urinary loss of potassium or reduction in serum potassium concentration. Thus, triamterene may represent a beginning in the development of new compounds with more specific natriuretic properties. 

Diuretics represent a heterogeneous class of compounds however, most of them can be measured using conventional absorbance detectors such as UV-analyzers without further derivatization at reasonable detection limits of approximately 0.01-2.0 pg/mL. Increased sensitivity and/or selectivity was reported for the loop diuretics furosemide and bumetanide as well as the potassium sparing diuretics amiloride and triamterene when using fluorescence detection due to the fact that numerous agents co-extracted with diuretics are visualized by means of UV but not fluorescence detection. 

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