The Use of Physical and Animal Models to Assess Bioavailability

Drug Absorption by Sublingual and Rectal Routes

“…Rectal gut-wall metabolism and metabolism by micro-organisms in the rectal lumen may decrease bioavailability, but there is very little information on this, although gut-wall metabolism is known to be very important in the upper part of the gastrointestinal tract for some drugs (Curry, D'Mello and Mould, 1970;Rivera-Calimlin et al, 1971;Barr, 1972;Dollery and Davies, 1972;Conway et al, 1973). Although this latter process is not likely to be important in the rectal wall, metabolism by microorganisms may be significant for some drugs, especially when hydrolytic and reductive reactions occur (Scheline, 1973).…”

The Neonatal and Juvenile Pig in Pediatric Drug Discovery and Development

“…Some of the earliest works including the pig (or its tissues) as a model for human pharmacology go back to the early sixties, when the effects of chlorpromazine on the activity of pig plasma cholinesterase [104] or the PK of oxazepam in pig were assessed [105]. Around 10 years later, the Canadian Federal Food and Dug Directorate started a series of works to evaluate the absorption of several drugs such as phenylbutazone, sulfisoxazole and sulfadiazine in pigs in order to evaluate their potential use in PK and toxicology studies [106]. In the same decade, more research characterizing the response of pigs (among other species) to different pharmacological molecules was published [107][108][109][110][111].…”

Which drugs should we be testing for bioavailability [editorial]?

“…This test would also act as a quality control for batch-to-batch variations. All these checks would need a reference standard and the requirements of the latter have been outlined (Barr, 1972 35,000 finished medicinal products obtained licences of right, because they had been on the market beforehand. They were not subjected to scientific scrutiny, but it was always implied, and the EEC directives now require, that these licences will be reviewed at a later date.…”