Under attack

London, Oct. 3: Fake ?Viagra? tablets made by Indian companies and sold illegally via the Internet could, in certain circumstances, induce heart attacks in men, according to new research at London University.

It is unclear, however, whether the Indian-made tablets really are harmful or whether the Pfizer Corporation, which makes the anti-impotence drug Viagra, is fighting to retain its domination of the worldwide lucrative market.

So far, there has been no comment by Indian companies which are trying to enter the market for anti-impotence drugs, so it is confusing as to whether the west is attempting scare tactics or its concern is genuine. However, it is clearly a breach of law to pass off Viagra substitutes as Viagra, which has been hailed as a wonder drug since it appeared on the market.

The latest research, presented recently at the British Pharmaceutical Conference in Manchester, came after the Medicines and Healthcare Products Regulatory Agency revealed that three batches of counterfeit drugs had entered the UK supply.

Prof. Tony Moffat, of London University, said that 100 tablets, which had arrived from countries including India, Singapore and Malta, had been tested. The pills cost around ?20 for four (in the US, Viagra is distributed to pharmacies in 30 tablet bottles and the retail price works out to $10 per tablet).

When the fake samples from the last test batch of around 30 tablets were sent to Pfizer, the company confirmed they were fakes, Prof. Moffat said.

Commenting on the proportion of Sildenafil, the active ingredient in Viagra, Moffat said: ?Most of the samples contained Sildenafil in much lower quantities than the real pills.?

He then sounded a stark warning: ?But if they had contained a much larger amount of Sildenafil, there is a possibility that a man could suffer a heart attack.?

The London University team did tests on samples of ?Viagra? bought online and analysed them using a new technique called near infrared (NIR) microscopy to check the ingredients.

The technique produces an ?image map? of thousands of spectra from a tablet sample, making it possible to identify the components in the tablet and the amount.

The researchers were shocked to discover that half the samples were probably fakes.

The researchers targeted websites which did not contain addresses or indicate where the drugs were coming from. The new tests allow researchers to focus in on particle size and distribution within the tablet which provide a clue to the tablet?s origin.

In this latest study research, Dr Nic Wilson, of London University, concentrated on Viagra, which is widely available over the Internet and is a major target for counterfeiters.

She said that NIR microscopy ?gives another layer of information. For example, a counterfeit tablet may contain lactose as an ingredient in the tablet bulk, whereas the authentic tablet does not. NIR spectroscopy (the old method of testing) could only show that the tablets are different, while NIR microscopy could actually identify the likely presence of lactose?.

Using the technique on known counterfeit tablets, the researchers found that most contained less of the active ingredient Sildenafil than bona fide Viagra.

The fake tablets were found to contain ingredients different from those in the genuine Viagra.

Wilson said: ?We don?t know that ?wrong? components will be harmful, but the user runs the risk of poor quality and possible toxicity, not to mention the fact there is a high probability that the tablets may have no clinical effect.?

The tablets almost have fingerprints which allow the country of origin to be identified.

?Once counterfeit tablets have been identified, their images can be added to a database,? explained Wilson. ?When other suspect tablets are seized and later identified as fakes, they can then be compared with the known counterfeits present in the database.?

She added: ?The identity of the components in the newly identified counterfeits and their distribution within the tablet can be compared with those in the database. This will help to link different sources of counterfeit tablets and to monitor the movements of batches of counterfeit tablets. It will therefore help the regulatory authorities and the pharmaceutical companies in the fight against the counterfeit medicine trade.?

The British research comes against the background of similar findings in America. An investigation by the Manhattan District Attorney?s office that began in January 2001 and went on for 17 months uncovered four supply streams of counterfeit Viagra ? three from China and one from India.