Gastric emptying rates of drug preparations. I. Effects of size of dosage forms, food and species on gastric emptying rates.

The gastric emptying rates of oral dosage forms of different sizes were studied in humans and beagle dogs measuring of marker drugs such as acetaminophen, aspirin and pyridoxal phosphate in plasma or urine. The marker drugs, except acetaminophen, were contained in enteric-coated granules or tablets which did not dissolve in the stomach but dissolved rapidly in the upper intestine. The gastric emptying rate of a dosage form of smaller size was faster than that of a larger size. The gastric emptying rates of dosage forms with different sizes did not correlate with each other inter-individually. The gastric emptying rates of dosage forms of any size were delayed when drugs were administered after taking a meal. The gastric emptying rates of dosage forms were extremely prolonged in beagle dogs after drug administration postprandially, and this restricted the use of beagle dogs as an animal model in bioavailability tests.