In vitro inhibitory activities and reversibility of tegoprazan and esomeprazole on porcine gastric H⁺/K⁺-ATPase. (A) The reaction was initiated by adding tegoprazan and esomeprazole to the reaction buffer followed by incubation at 21°C for 30 minutes. Data are presented as the mean ± S.E. of two independent experiments. (B) The washout method assay was employed to confirm the reversible mechanism of action of tegoprazan. Assays were performed using porcine gastric H⁺/K⁺-ATPase in freeze-dried vesicles. Data are presented as the mean ± S.D. of three independent experiments. The significance of differences between means was determined by the Student’s t test. *P < 0.05 vs. control.

Effect of tegoprazan and esomeprazole on gastric acid secretion in pylorus-ligated rats. Tegoprazan (A) and esomeprazole (B) were administered orally 30 minutes before pylorus ligation. Five hours later, the rats were sacrificed, and the gastric contents were collected and pH was measured. Each column represents the mean ± S.D. from five to six rats. The significance of differences between the means was determined by the Mann-Whitney U test. *P < 0.05 vs. vehicle.

Effect of tegoprazan and esomeprazole in a rat model of reflux esophagitis. Reflux esophagitis was surgically induced by ligating both the pylorus and foregut of rat stomach. The rats were laparotomized under anesthesia, and the transitional region between the forestomach and glandular portion, and the duodenum was ligated with a silk thread. Prior to duodenum ligation, tegoprazan and esomeprazole were intraduodenally injected. Four hours after surgery, the gastric contents and esophageal mucosa tissues were collected. (A) Macroscopic appearance of the esophageal mucosa in rats. (B) Gastric contents were collected 4 hours after surgery, and total acid output was calculated. (C) Esophageal mucosal proteins were extracted from mucosa tissues using lysis buffer, and MPO concentration was measured. Each column represents the mean ± S.D. from three rats. The significance of the difference between means was determined by the Student’s t test. *P < 0.05 vs. vehicle.

Effect of tegoprazan and esomeprazole in rat models of gastric ulcer. Acute gastric ulcers were induced by three different inducers. (A) After 30 minutes of tegoprazan and esomeprazole administration on a single day (closed columns) and daily for 5 days (open columns), naproxen was orally administered to each animal three times at 2-hour intervals. Four hours after the last naproxen administration, the rats were sacrificed. (B) After 1 hour of tegoprazan and esomeprazole administration, absolute ethanol was orally administered for 1 hour. (C) Ten minutes after tegoprazan and esomeprazole administration, rats were placed in a restraint cage and immersed in water at 21°C for 4 hours. The ulcer area was analyzed by an image analyzer and the ulcer lesion was calculated per total lesion of the stomach. Each column represents the mean ± S.E. from 6 to 10 rats. The significance of the difference between means was determined by the Mann-Whitney U test. *P < 0.05 vs. vehicle.

Effect of tegoprazan and esomeprazole in a rat model of acetic acid–induced gastric ulcer. The rats were anesthetized with xylazine/ketamine, and the stomach was incised via midline epigastric incision. The antrum was clamped using a sponge forceps, and 100 μl of 60% acetic acid was then injected into the clamped area for 40 seconds. After 2 days, tegoprazan and esomeprazole were orally administered for 5 days. (A) Gastric ulcer area data from 10 rats are presented as the mean ± S.D. The significance of the difference between means was determined by the Mann-Whitney U test. *P < 0.05 vs. vehicle. (B) Gross appearance of gastric mucosa in rats and quantitative analysis.