Pharmacological properties of colloidal bismuth subcitrate (CBS, DE-NOL)

In pharmacological ulcer models in rats colloidal bismuth subcitrate (CBS) demonstrated anti-ulcer activity. This was neither a result of an acid neutralizing nor of an acid secretion inhibitory effect. Both in vitro and in vivo, an anti-peptic action was found. At low pH CBS precipitates and was shown to form a coating on the gastric wall especially on the ulcer crater. This coating most likely forms a protective barrier to the peptic activity of gastric juice. Low toxicity was seen following chronic daily administration of high doses of CBS for 3 months to rats and 6 months to dogs. Although the blood levels were more elevated in rats, the tissue bismuth levels were comparable in the two species (except for the caecum). The chief bismuth-excreting organs, the kidneys, showed relatively high concentrations, while the brain-concentrations were extremely low in concordance with the absence of nervous system toxicity.