Evaluation of the gastric absorption and emptying of drugs under various pH conditions using a simple intubation method: application to diclofenac

Sodium diclofenac (50 mg) together with [14 C]‐PEG as a non‐absorbable marker were dissolved in 400 ml of water (A), phosphate buffer pH 7.5 (B) or a homogenized meal (C). Each of these was ingested in random order by six volunteers on 3 consecutive days. Some gastric absorption of the drug was established with C but the plasma drug concentration‐ time profiles mainly reflected the process of gastric emptying.