Effect of Polaprezinc, a Novel Anti-ulcer Agent, On the Gastrointestinal Absorption of Antibiotics in Dogs

Polaprezinc is a zinc complex of L-carnosine. Studies on the drug interaction of some antibiotics with polaprezinc in dogs were performed, because of the reported changes in the gastrointestinal absorption of some antibiotics in the presence of di- or tri-valent cations such as aluminium, ferrous and calcium ion. The gastrointestinal absorption of norfloxacin was significantly reduced by coadministration with polaprezinc in dogs, but that of levofloxacin and sparfloxacin not affected. The Cmax and AUC of tetracycline were slightly decreased by polaprezinc treatment. On the other hand, sucralfate, containing aluminium, significantly impaired the absorption of norfloxacin, levofloxacin and sparfloxacin. The effect of sucralfate on the absorption of tetracycline was greater than that of polaprezinc. Differeces between polaprezinc and sucralfate on the absorption of antibiotics may result from different ability of each metal ion for chelate formation with antibiotics. In non-fasted dogs, polaprezinc did not affect the absorption of norfloxacin, levofloxacin and sparfloxacin. The interaction of norfloxacin with polaprezinc was markedly reduced by food. The obtained results indicated that the amount of zinc dissosiated from polaprezinc decreased by pH elevation in stomach due to food intake. Sucralfate severely impaired the absorption of norfloxacin, but slightly that oflevofloxacin and sparfloxacin.