Glipizide

glipizide tablets chosen as the reference (containing 5 mg glipizide in total weight of 200 mg, RLD) were purchased from Pfizer Co., Ltd. (Dalian, China). Two batches of glipizide were obtained from Weihai Disu Pharmaceuticals Co., Ltd. (Shandong, China). Reference standards of glipizide (99.5% purity) and gliclazide used as internal standard were obtained from the National Institute for Control of Pharmaceutical and Biological Products (Beijing, China). Lactose monohydrate was purchased from Jiangsu DaoNing Pharmaceutical Co., Ltd. (China). Microcrystalline cellulose, starch and colloidal silicon dioxide were gifted by Anhui Sunhere Pharmaceutical Excipients Co., Ltd.(China). Stearic acid was provided by Huzhou Zhan Wang Pharmaceutical Co., Ltd. (China). Methanol, acetonitrile and formic acid, all with HPLC grade were procured from Fisher (USA). Ammonium acetate (HPLC grade) was purchased from Dikma (Richmond Hill, NY, USA). Deionized-distilled water was used throughout the study.

Peptic ulcer patients with T2DM were treated with 10 mg glipizide daily (Pfizer, Inc., New York, NY, USA) to lower the blood glucose levels, and patients with characteristics of hematemesis or hematochezia were treated with daily injections of 8 units novolin (Novo Nordisk, Bagsvaerd, Denmark). Omeprazole (20 mg; Hainan Haili Pharmaceutical Co. Ltd., Haikou, China) was administered as an antiulcer proton pump inhibitor for 8 weeks in peptic ulcer patients with or without T2DM. In addition, H. pylori infection in peptic ulcer patients was treated with a combination of amoxicillin (0.5 g every 8 h; CSPC Pharmaceutical Group, Shijiazhuang, China), clarithromycin (250 mg every 12 h; Abbott Laboratories, Lake Bluff, IL, USA) and metronidazole (1.2 g daily; Novartis, Basel, Switzerland) for 2 weeks. This treatment regimen was maintained for 8 weeks.