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Amprolium [1-(4-amino-2-propyl-5-pyrimidinemethyl)-2-methyl-pyridinium chloride hydrochloridel is a basic (quaternary) organic compound. At very low plasma concentration, it is cleared by the kidney at a rate approximating renal plasma flow in the dog. Its renal clearance is not depressed by organic acids (p-aminohippurate or probenecid) but is reduced by the quaternary base, mepiperphenidol. Acetate and pantothenate may influence the clearance of amprolium but, if this is the case, the effect is less than for p-aminohippurate. Its clearance is depressed as urinary pH is increased. The clearance of amprolium was not altered over a substantial range in urine flow at either high or low urinary pH.

The saluretic and uricosuric responses elicited by a novel agent, MK-196, have been studied in a great ape, the chimpanzee. This agent is orally active at very low doses and has a prolonged duration of action. Probenecid does not appear to influence the saluretic and uricosuric properties of MK-196. Net tubular secretion of urate was reduced by MK-196. Urinary pH changes did not compromise the efficacy of this new agent. On a dose basis, MK-196 was more saluretic (and uricosuric) than ethacrynic acid or furosemide and possessed a longer duration of action. Because of the marked natriuresis caused by MK-196, some increase in potassium excretion occurred.