History of Viagra

The diamond shaped blue pill Landa Pharmacy Viagra, which is responsible for giving a whole new perception of sexuality to the modern society, has a similarly interesting history behind its invention. The inventors of Viagra actually wanted to invent a medicine for the cure of cardio-vascular diseases, but fortunately or unfortunately, they developed a medicine which could reverse impotence or erectile dysfunction for the first time.

An extraordinary Side effect of an ordinary Drug

In the year 1991, employees of Pfizer at Sandwich, Kent discovered that chemical compounds belonging to the pyrazolopyrimidinone class were useful in treating heart problems like angina or chest pain. During clinical trials under the direction of Ian Osterloh it was found that the drug had little or insignificant effect on angina. But during this phase, an unexpected side effect of this medicine was observed. Sildenafil could improve and sustain a man’s penile erection. Pfizer than stopped the research on Sildenafil as heart medication and initiated investigation on it for penile erection.

The Invention and the Inventors

The names and status of the original inventors or the non-inventors of drugs manufactured by Pfizer are secrets that every employee of the company has to maintain. However, in spite of such high levels of secrecy, Peter Dunn and Albert Wood are given the dues for the process that facilitated the invention of Viagra by the British Press.

The names of these two scientists appeared on Pfizer’s patent application paper (WOWO9849166A1) for the manufacturing process of Sildenafil Citrate. But it was only in the year 1991 that the potency of Sildenafil to cure angina was discovered by Andrew Bell, Dr David Brown and Dr Nicholas Terrett. In fact Terrett was named in the 1991 patent for the use of Sildenafil as a treatment for heart problems, and he is thereby recognized as the ‘father of Viagra’. In the words of Dr. Terrett, “Basically me and my team discovered how useful the drug might be… they (Wood and Dunn) created a way of mass producing it only.

And again it was Nicholas Terrett and his colleague Peter Ellis in 19994, who discovered that the drug can be very effective in enhancing the flow of blood to the penile region in patients suffering from erectile dysfunction while they were investigating on the utility of Sildenafil as a heart medicine. Sildenafil was found to increase the muscle relaxing effects of nitric oxide, a chemical that generally gets released when a person is sexually stimulated. The smooth relaxation of the muscle in the penis facilitates higher rate of blood flow and helps in producing an erection.

Dunn and Wood worked on the critical nine-step process to synthesize a Sildenafil compound into a pill at that particular point of time. However, the patent name Viagra as the first prescription pill for the treatment of impotence or erectile dysfunction was approved by the FDA on March 27, 1998.

As it happens often in the pharmaceutical industry, Pfizer doesn’t reward or recognize any particular scientist as the inventor of Viagra. The company claimed that it was a common effort, with lots of scientists or inventors being a part of the entire process to produce Viagra. And with the economy of space in the patent application, only names of the heads of departments are listed.

Nonetheless, Dr Simon Campbell, who until recently was the Senior Vice President of Medicinal Discovery at Pfizer and oversaw Viagra’s development, was considered to be the inventor of Viagra®, by the American Press.

The Nine-step Process to Synthesize a Sildenafil (Viagra)

Methylation of 3-propylpyrazole-5-carboxylic acid ethyl ester with hot dimethyl sulfate

Hydrolysis with aqueous NaOH to free acida Nitration with oleum/fuming nitric acid

Carboxamide formation with refluxing thionyl chloride/NH4OHa Reduction of nitro group to amino Acylation with 2-ethoxybenzoyl chloride Cyclization Sulfonation to the chlorosulfonyl derivative Condensation with 1-methylpiperazine.

Empirical formula = C22H30N6O4S

Molecular weight = 474.5

Solubility = 3.5 mg/ml in water.

Sales and Success of Viagra

With the annual sales of Viagra hitting the $1 billion mark in 1999-2001, Viagra began to be considered as one of the highest money grossing prescription drugs it has ever produced. In a report published on July 10 1998 in the New York Times, the sale of the erectile dysfunction drug propelled in increasing the second-quarter profit margin of Pfizer by a whopping 38%.

The profits of Pfizer rose dramatically after the introduction of Viagra in the ED drug market, with the revenue climbing 25 % from $2.91 Billion to $3.63 Billion in late April. The company share value had a gradual growth on the New York Stock Exchange, with shares increasing by $2.50 a share to $166. In fact, Pfizer went ahead, encouraged by the growth and reported its second-quarter earnings earlier than the date, analysts were expecting.