A2bR x A1R x PDE

Main research purpose: This study investigates the pharmacokinetic characteristics of theophylline sustained-release tablets (test preparation, specification: 100 mg) provided by Hunan Shentaichun Pharmaceutical Co., Ltd. and theophylline sustained-release tablets (reference preparation R, trade name: UNICONTM, specification: 100 mg) certified by Nichiyo Co., Ltd. under the same conditions when taken orally once in a single dose in healthy subjects under fasting and postprandial conditions, evaluates the bioequivalence between the two preparations, and provides a basis for the consistency evaluation of the test preparation. Secondary research purpose: Observe the safety of the test preparation theophylline sustained-release tablets (specification: 100 mg) and the reference preparation theophylline sustained-release tablets (trade name: UNICONTM, specification: 100 mg) taken orally once in a single dose in healthy subjects under fasting and postprandial conditions