More Than A Patch-Up Job
Apr 28 2004
By John Ives

For 10 years they have been the accessory of choice for any smoker serious about quitting.

But now patches are moving beyond nicotine replacement to treat new groups of people in need of an alternative to their
daily pills or painful injections.

The first contraceptive patch, Evra, was introduced in the UK last summer after success in America, and new products
for diabetics and depressives are expected in the US within the next year.

Those products will join a market now worth as much as £4.5 billion in global sales, according to analysts Greystone
Associates, and expected to grow rapidly in coming years as the technology continues to develop.

Dr Robert Donnelly, medical director of Evra maker Janssen-Cilag, says there is growing interest in patches in the
pharmaceuticals world and predicts a bright future for the little sticky strips.

"More and more companies are investigating this area as a way for delivering medication," he says. "I'm confident there
will be more.

"By and large patients seem to quite like the idea of having a patch on the skin. It might sound paradoxical, but it
seems a little less like having to take a medicine."

:: HOW IT WORKS

Today's skin patches work by releasing a reservoir of medicine through the skin and straight into the blood stream,
without the discomfort of injections.

However, only small molecules such as nicotine or estradiol (COR) - the chemical used in hormone replacement therapy
(HRT) patches - can be absorbed through the skin, meaning scientists have had to come up with new ways to deliver their
drugs.

Professor Adrian Williams, an expert in transdermal drug delivery at the University of Bradford, explains: "The skin is
designed to keep the outsides out and the insides in, so trying to get any medicines in is very difficult.

"Things like nicotine patches and hormone replacement therapy patches have been massively successful, but these
products came to the market eight or 10 years ago and then there was a stop.

"Now, instead of looking at what drugs they could deliver through the skin, drugs firms are starting to look at the
conditions that need to be treated. For example, diabetes is difficult to treat because of all the injections, so it
would be nice to have that patch.

"And Parkinson's - if you have a tremor it's difficult to take oral medication, so a patch is easier."

In order to get larger chemicals like insulin through the skin, patches are now being developed with tiny needles one-
tenth of a millimetre in length, just big enough to pierce the protective outer layer of skin without reaching the
body's pain receptors.

Drugs firms are also developing small pumps to force medicine through the skin, while small electrical currents could
also play a similar role, says Professor Williams.

Welsh firm Starbridge Systems is one of the manufacturers working on 'micropump' patches to deliver insulin.

Chief executive Joseph Cefai says: "The pump will be small, cheap and effective and also simple to use, which will be
particularly beneficial to people who have developed diabetes in later years - those who are old or have poor sight or
mobility.

"And because the pump will allow them to accurately control their insulin doses, they will be able to get back to
normal life, eating, sleeping and exercising as they wish."

Professor Williams says in the future even more conditions will be treated simply by putting on a patch.

"Hopefully the next thing will be to treat things like attention deficit disorder, or Parkinson's, where it's going to
be hard to regulate doses.

"Then five, 10 or 20 years down the line one of the great aims would be to do vaccinations by the skin. Quite a lot of
effort has been going on in that field."

:: WHAT'S AVAILABLE?

HRT - Hormone replacement therapy was the first treatment to use patches, and the products have now been available for
more than 20 years. The patches deliver a dose of female hormone estradiol, and will generally be used to treat the
symptoms of the menopause.

NICOTINE: Over-the-counter patches such as Nicorette, NiQuitin and Nicotinell have proved hugely popular with people
struggling to stop smoking. A steady stream of nicotine helps ease smokers' cravings and wean them off the habit.

PAIN RELIEF: Duragesic, the leading pain relief patch, generated global sales of 1.63 billion dollars last year. It
delivers a powerful drug called Fentanyl, and is primarily used to help ease the pain suffered by cancer patients.

COSMETIC: Acne patches and cleansing and moisturising strips for the face are becoming more common, and anti-wrinkle
patches are also available.

OTHER: Patches to treat angina have been available for several years, and then there are contraceptive patches, patches
to treat motion sickness, and male testosterone patches. You can even find dieting patches and breast enhancement
patches, although their benefits may not always be scientifically proven.

:: PROS

Patches can deliver a slow, steady dose of the drug over a period of up to a week, making them far better for people
too busy or just too forgetful to stick to a daily course of pills.

Pills will often carry higher doses than necessary because some of the medicine will be broken down in the stomach.
Patches can deliver a more accurate amount.

Delivering drugs straight into the blood stream via a patch can avoid some side effects of pills, ranging from nausea
or diarrhoea to potential damage to your liver.

Patches are a pain-free alternative to needles, and a valuable resource in treating the thousands of people with an
aversion to needles and injections.

CONS

Some wearers can develop skin rashes where the patch is applied. If the rash becomes serious, you should contact your
doctor and may have to seek alternatives.

It can take longer for drugs delivered by a patch to take effect, meaning it's unlikely they will ever be used to offer
quick relief from complaints like headaches.

SOURCE: ic Solihull.co.uk, UK
http://tinyurl.com/3x4eg

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