The secrets of female Viagra
2/20/13

The announcement of the development of a testosterone nasal spray (a ‘Female Viagra’!) by a team from Liège, aimed at improving women’s sex life, was lucky enough to attract the attention of the media. But for the researchers, for whom Tefina (its name) only represents a small part of their activity, an experiment such as this is almost routine: the University of Liège’s Laboratory of pharmaceutical technology and biopharmacy carries out a great deal of innovative research that is far more complex than the development of this nasal spray. But why this particular route of administration? The contraceptive pill is taken orally, so why not testosterone?

It was a strange turn of fate that thrust the University of Liège’s Laboratory of pharmaceutical technology and biopharmacy into the spotlight. It was the announcement of the development of a testosterone nasal spray (a ‘Female Viagra’!) by the team from Liège, aimed at improving women’s sex life, that was lucky enough to attract the attention of the media. But for the researchers, for whom Tefina (its name) only represents a small part of their activity, this experience was slightly frustrating. “Our discipline is relatively unknown; it’s rarely mentioned in the press", admits Professor Brigitte Evrard, who manages the laboratory and faced her baptism of fire in front of journalists. “And yet we carry out a lot of innovative research that is far more complex than the development of this nasal spray”(read the box). Let’s take this opportunity then to discover the discipline of pharmaceutical technology which actually has a great many ramifications. And for the red thread, what if we were to take... the development of a nasal spray?

Why not orally?

First of all, why this particular routeof administration? The contraceptive pill is taken orally, so why not testosterone? The fact is that any drug taken via the traditional oral route passes through the digestive system, where it is absorbed through the network of veins that drain the intestines and end up in the liver via the portal vein. The liver is our main detoxification centre: it metabolises all the foreign molecules that arrive in it to prepare them to be excreted either into the intestines (a sort of ‘return to sender’) or via the kidneys. This system called the ‘first-pass effect’ provides an excellent barrier against poisoning... but it is also responsible for a considerable loss in the efficacy of the majority of drugs we swallow. In the case of hormones such as testosterone, oestrogen, etc., the first-pass effect is significant.   This is especially true for the contraceptive pill, which means it has to be administered in high doses so that a sufficient amount reaches the blood stream. Oral administration, which seems the obvious choice, isn't always the most effective.

(EN)voies-administrationThere are more interesting alternative routes – one of the key areas of research of the laboratory of Pharamaceutical Technology in Liège – that circumvent the compulsory passage through the liver. Such is the case for transdermal (patches, gels), inhalational (puffers, inhalations), rectal (suppositories), intrauterine and vaginal (hormone-based coils, vaginal rings), sublingual (because the oral mucous membrane isn’t subservient to the portal vein system), and of course transnasal routes. For instance, in the case of hormones for contraceptive purposes, using the vaginal ring that gradually releases an oestroprogestative combination allows the dose administered by the mini pill to be reduced by 20. And in the case of testosterone, where the mannish side effects - hyperpilosity, a husky voice – are highly undesirable in women, high doses must be avoided at all costs. Therefore, with a ratio of 1 to 20, oral administration is clearly not the best solution.

Page : 1 2 3 4 next