Structural advantage of polaprezinc (Z-103) as a chelate compound. Comparison with a combination of its relative compound on various experimental models of gastric lesions in rats

In order to clarify the structural advantage of polaprezinc(Z-103) as a chelate compound, the anti-ulcer effects of Z-103 were compared with a combination of zinc sulfate and L-carnosine (mixture), substances related to Z-103, on various experimental models of gastric lesions in rats. Z-103, but not mixture, prevented the gastric lesions induced by absolute ethanol at 4 hr after oral administration. The inhibitory effect of Z-103 was observed until 5 hr after administration. The efficacy of Z-103 was more potent than those of mixture on indomethacin induced gastric lesions and acetic acid induced gastric ulcers. Z-103 (3-30 mg/kg) also prevented the development of gastric lesions on water-immersion stress model, in a dose dependent manner. However, mixture at a dose equivalent to Z-103 had less potentency than that of Z-103 in this model. Zinc sulfate and mixture, but not Z-103, were produced a transmucosal potential difference reduction. These results indicate that Z-103 possesses the structural advantage as a chelate compound on durable effect, increase in pharmacological effect and maintain gastric integrity for the damage with zinc.