Abstract: The invention relates to an improvement in a conventional method for the determination of uric acid involving uricase/catalase/aldehyde dehydrogenase, resulting in the formation of produced NAD(P)H as a measure of the initial uric acid present, which improvement comprises adding at least one compound selected from oxalates, malonic acid mono-lower alkyl esters, trihaloethanols, pyrazole, pyridine, substituted pyrazole and pyridine wherein the substituents are selected from lower alkyl and halogen, pyridine carboxylic acids, pyridine carboxylic acids substituted with a lower radical, pyridine carboxylic acid amides and pyridine carboxylic acid lower alkyl esters, thiourea, isobutyramide and chelate-forming complexing agents, in order to suppress disturbance-causing creep reactions in said method. Reagents containing such additive compounds are also provided.

Abstract: Porous tablets are produced by mixing the tablet components with a liquid solvent which is inert towards the components of the tablet and which freezes at a temperature from about -30 to +25.degree. C, the solvent constituting about 5 to 80% by weight of the total mixture, introducing the mixture into an inert cooling medium at a temperature low enough to solidify the solvent, pressing the mixture including the solidified solvent into tablets at a temperature below the freezing point of the solvent, and then evaporating the solvent from the tablets. Advantageously the solvent is water, cyclohexane, benzene and/or tert.-butanol, optionally containing alcohol. The tablets readily disintegrate in liquid.