This page was written in HTML by Pascale Hazel. If you have any comments, please mail me.

The 2D molecules were drawn using chemdraw.

I used the following databases to find information about sildenafil :

Beilstein Crossfire where the search for the 2D structure of sildenafil gave one hit: information about the synthesis was found in the Bioorganic & Medicinal Chemistry Letters, Vol 6, pp. 1819-1824, 1996.

BIDS, the Bath Information Delivery Service gave many hits, but not that many were actually that useful. It was very easy to use though and the fact that the results of searches could be e-mailed increased its efficiency.

The Libertas System with the Imperial College library was used to find the references found above.

I also tried using The Merck index, although this was not very successful. It was not as user friendly as the other search engines, and I did not find it very helpful to find references.

The CambridgeSoft Chemfinder system did give a bit of information on the structure of sildenafil, but it did not actually have any physical data on the molecule.

I also searched the internet for more information. This was quite successful. There is a lot of information about sildenafil on the net because it is much talked about at the moment. I visited the Pfizer site which gave a lot of information about the tests that had enabled to establish the effectiveness of the drug, and also had lots of information about the side effects of the drug and the precautions it is necessary to take. The IBM patent search was used to find the patent deposited for Viagra. It gave a lot of information about the synthesis and especially about the reagents that could be used for all the steps of the reaction. I did not reproduce all of this information here, but it is quite interesting to read.

There is a lot of information about Viagra on the site of the Centre for Drug Evaluation and Research which is run by the US Food and Drug Administration.
There is also some information on Viagra on the Nitric Oxide: Basic Research and Clinical Applications, Extensive Abstracts site, which has some useful diagrams about how an erection works.
Another site which had a lot of information about Viagra, was written by a graduate student at the Medical College of Virginia.
I also found the Chemistry home page very useful because it contained lots of 3D images of sildenafil and related molecules.
The Time magazine has an interesting and diverting article about Viagra, The Viagra Craze. It is not exactly scientific but it's a good read.

Several search engines were used to look for information on Viagra on the web, but the most useful two were found to be Hotbot and metacrawler.

This webpage was designed to be efficient and fast. It loads rapidly and the simplicity means that people are not distracted from the contents of the page. I chose a white background so that the text was easy to read.