TGA Internet site archive

The content on this page and other TGA archive pages is provided to assist research and may contain references to activities or policies that have no current application. See the full archive disclaimer.

Fifty years of independent expert advice on prescription medicines

Book pagination

12 February 2014

Quality and bioavailability

In the late 1960s it became apparent that a lack of studies measuring bioavailability - how much medicine gets into the blood and how quickly this happens - could have significant clinical impact.

An example of this was when reports were received in 1968 concerning overdose symptoms in Australians and New Zealanders taking the anticonvulsant medicine phenytoin sodium.

These patients had taken the correct number of capsules, and the capsules contained the correct quantity of medicine, yet their blood contained excessive concentrations of the active medicine. It was discovered that all of the overdosing events occurred with a new formulation, in which one of the inactive ingredients had been changed.

With this new understanding of how much bioavailability can vary between products and how important this is clinically, ADEC set out some circumstances in which all companies would be required to provide bioavailability data.

Sir John Lewtas

Sir John Lewtas (Jock) Frew OBE, MD, FRCP, FRACP, FACP, fourth chair, 1982-1985

Sir John was one of the last of the honorary physicians of the Royal Melbourne Hospital, and described himself as a 'relic' of the honorary system. Sir John had an interest in Malaysia and Singapore, having been a prisoner of war there, and was an Honorary Fellow of the Academy of Medicine of Singapore.

Data fabrication

The importance of bioavailability was well established in the eighties, but these studies cost companies money; the temptation to invent data proved too much for one company.

A special meeting of ADEC was convened in 1986 when this company's fraud was discovered, which affected a total of 33 medicines. ADEC recommended that repeat bioavailability studies should be required within the year, and this resulted in 13 of the medicines being removed from the Australian market.

This reinforced the importance of regulating the quality and bioavailability of medicines. The best way to provide expert advice on such issues was considered to be a separate group of experts, so a working group was set up, with a subcommittee formally established in 1989.

Today, the Pharmaceutical Subcommittee makes recommendations on the pharmaceutical chemistry, quality control, bioavailability and pharmacokinetics of prescription medicines.

Book pagination