Countering the fakers

ROGER JEWSBURY, Head of the department for chemical and biological sciences at the University of Huddersfield, looks at the drug-faking menace

Counterfeiting is big business — a fake Rolex will tell the time, at least for a few weeks, but a counterfeit medicine can leave you seriously ill . . . or worse.

The sums involved are staggering. Recently, 5,000 packets of counterfeit flu prevention and treatment medicine Tamiflu were seized with a value of £500,000.

They were easy to spot as they were labelled “Generic Tamiflu” — there is no such product.

Counterfeit medicines are not often spotted so easily and chemical analysis is required. Analytical chemists look for what should be there — the “active ingredient” — as well as for what shouldn’t, which might be toxic.

Counterfeiting drugs is not new. “The Third Man”, written just after the Second World War by Graham Greene, was about the search for a counterfeit penicillin smuggler in Vienna. Counterfeiting has increased rapidly in recent years, particularly in the developed world but also in Britain. There have been cases of deaths because of poisonous ingredients or the absence of an active drug.

In 1998, 33 children died in India after taking a cough syrup which contained toxic diethylene glycol, used in the manufacture of plastics. This compound has also been found in toothpaste — in 2007, it was found in fake toothpaste sold at a car boot sale in Derbyshire. So how can analytical chemists check the authenticity of the composition?

A simple chemical test that generates a colour by reaction with the active ingredient might be used. Malaria is a deadly disease that could affect 40 per cent of the world’s population and anti-malarial drugs are a major target of counterfeiters. These drugs have chemical groups which react with other chemicals to form dyes with a colour characteristic of the drug. This colour test was introduced a few years ago but testers have to remain alert.

The counterfeiters started to use about 20 per cent of the real drug to attempt to fool the test, but these tablets would not protect from malaria.

Some compounds are regularly subject to counterfeiting, and a technique known as near infra-red spectroscopy can be used.

Coloured compounds absorb light — which is why we see their colour — but colourless chemicals will also absorb light in the infra-red region, which is just outside the range that the human eye can see. The pattern of this infra-red absorption is characteristic of the components of the tablet. In the case of the much counterfeited Viagra, a database has been established of products from all eight Pfizer factories that manufacture Viagra pills around the world. No illicit manufacturer can exactly replicate the Pfizer process and so other tablets have a different pattern of infra-red absorption and can be identified. Tablets that do not contain the magic ingredient may not be dangerous but will certainly disappoint! Some ‘blue pill copies’ have been found to contain the active ingredient at three times the recommended amount and these could be dangerous.

Another, relatively inexpensive, technique called thin layer chromatography or “TLC” is used where a database does not exist. TLC is similar in principle to the way black ink separates into different colours when an ink blot is absorbed slowly onto blotting paper. In TLC, the different chemicals separate as they travel along an absorbent layer attached to a plate. Many pharmaceutical chemicals are colourless and we might need to treat the plate to ‘see’ the chemical components.

All these tests can be carried out in a mobile laboratory. The Chinese authorities do just that to counter the fakers. Alternatively, samples can always be sent to a large laboratory such as is found in some universities such as Huddersfield for comprehensive analysis using the most modern techniques.