Five years after the adulterated heparin scandal that claimed the lives of dozens of people in the US alone, the FDA has published final guidance on monitoring supplies of the ingredient.

In 2008 various pharma companies - including Baxter and B Braun Medical - were forced to recall products containing China-sourced heparin contaminated with oversulphated chondroitin sulphate (OSCS), which led to serious allergic reactions and the deaths of more than 150 people in the US alone.

The case was the most high-profile example of economically-motivated adulteration to date, and was believed to have been prompted by a swine shortage in Asia which made pig intestines - the raw material from which heparin is extracted - extremely scarce.

On investigation it emerged that the heparin API was laced with cheaper OSCS to fool quality control labs, as the contaminant was indistinguishable from heparin using the standard identity testing recommended at the time. All told more than 20 different suppliers - mostly based in China - were implicated in the complex supply chain for the contaminated API.

The FDA's final guidance marks the culmination of a great deal of work refining quality control measures to ensure that adulteration of contamination on this scale, would in future be picked up before patients are harmed.

The document lays out methods to test the quality of bulk, unrefined heparin on top of those set out in the US Pharmacopeia (USP), which were themselves updated last year in light of the scandal, and also provides advice for drugmakers on how to ensure the sources they use for heparin - including the manufacturer of crude heparin and any repackers and distributors who handle it before receipt and use - are reliable.

In addition to setting out requirements for OSCS testing, it also advises the use of additional testing to make sure heparin is sourced from pigs and not other animals, particularly cows which could pose the risk of patients being exposed to infectious agents such as transmissible spongiform encephalopathies (TSEs).

The FDA came under some criticism in the wake of the heparin scandal for not doing enough to ensure that drugs and ingredients sourced from overseas are sufficiently safe.

The incident prompted a major change in the agency's approach to regulating the pharmaceutical supply chain in an increasingly globalised marketplace, for example allying with other regulatory authorities around the world on inspections, building information-sharing systems and intelligence sharing.

It has also been progressively opening up offices in other countries, including three in China and two apiece in India, Africa, South America and Europe.