[Effect of nontoxic inhibitors on the nitrosation of drugs under conditions simulating the human stomach]. / Wirkungen einiger nicht-toxischer Inhibitoren auf die Nitrosierung von Arzneimitteln unter simulierten Bedingungen des menschlichen Magens.

ABSTRACT

The influence of sulphamic acid, sulfanilamide, p-aminosalicylic acid and ascorbic acid on the nitrosation behaviour of Analgin (active agent noramidopyrinmethane sulfonate) was investigated in the pH range between 1.2 and 6.0 under simulated conditions of the human stomach. Using a colorimetric measuring method, the three last-mentioned compounds proved suitable as nitrosation inhibitors; preference should be given to ascorbic acid because of its better inhibitory capacity in the very weakly acidic pH range. Sulphamic acid is inadequate because it stimulates nitrosation in this pH range. The distinct inhibitory action of ascorbic acid was verified under simulated conditions of the human stomach in further 9 drugs undergoing nitrosation at different rates, which contain the active agents aminophenazone, clomipramine, imipramine, desipramine, ampicilline, oxacilline, phenoxymethylpenicilline, ethambutole or piperazine. Despite the use of high doses of ascorbic acid, no complete inhibition of nitrosation could be achieved in the majority of drugs investigated.