"Patch" Technology is Being Tried for Testosterone and Other Sex Hormones
In response to what a number of experts consider an unmet medical need, transdermal testosterone and combination testosterone/estradiol patches for women are being developed by TheraTech, Inc. (Salt Lake City, Utah), in partnership with Procter and Gamble Co. (Cincinnati, Ohio).
While many people think of testosterone strictly as "the male sex hormone" and estrogen as "the female sex hormone," a small amount of testosterone (about 5 percent the level found in men) is normally produced by a female's ovaries and adrenal glands. Blood levels of testosterone as well as estradiol and progesterone fluctuate in accordance with the menstrual cycle, and experts believe that the balance of these hormones plays a significant role in the health and well-being of women.
A variety of conditions can put women at risk for testosterone deficiency, including natural or surgically induced menopause, adrenal insufficiency, and various medical treatments. Clinical symptoms of testosterone deficiency include decreased libido, a drop in energy and a diminished sense of well-being. Testosterone replacement therapy holds promise not only for reducing these symptoms, but may also improve memory skills in testosterone-deficient females, while helping in the prevention and treatment of osteoporosis.
The goal of testosterone replacement therapy is to restore testosterone to normal physiological levels, yet few options have been available for replacement of natural testosterone at the very low levels produced by healthy young women.
According to Alan Behunin, Manager of Investor Relations, TheraTech, Inc. (Salt Lake City, Utah), one of the benefits of the TheraTech transdermal system for testosterone administration is that it allows delivery and maintenance of very low doses of hormone. "When testosterone is given by injection or orally, there are peaks and valleys in the blood level of the hormone. With the patch system, a consistent blood level is achieved." In addition, since the drug is absorbed directly into the blood stream, much lower dosages can be used. Compliance and convenience are additional benefits.
"We make two transdermal systems," explains Behunin, "With MTX, our matrix patch, a mixture of adhesive, drug and special penetration enhancers are laminated onto a thin film. MTX is used when the amount of drug administered is very low, as with the testosterone preparation for women; for drugs that readily penetrate the skin, such as Nicotine; and for small molecule drugs that are readily absorbed through the skin.
TheraTech's LRS (liquid reservoir system) contains much stronger penetration and permeation enhancers and is used for larger molecule drugs or larger doses, as in the testosterone patch for men. LRS is characterized by a central "bubble" that contains the drug and absorption enhancers in a pharmaceutical gel, and is sealed with concentric rings of adhesive. According to Behunin, TeraTherm's particular area of expertise is in the development of exceptional permeation enhancers. "With transdermal patches, the skin is the limiting factor. The product that best moves the drug through the skin barrier in a controlled and consistent manner is at a distinct advantage."
TheraTech, Inc. specializes in the development and manufacture of a variety of controlled-release drug delivery systems and products, including transdermal patches and oral transmucosal (OTM) systems. Over 20 products are currently in development and 46 patents have been issued or are pending.
TheraTech and P&G already have a successful relationship with their estrogen replacement patch, Alora, launched in the U.S. last May. Their new joint venture, the testosterone patch for women, is nearing the end of Phase II clinical trials designed to evaluate its efficacy in the treatment of decreased libido related to testosterone deficiency. According to Behunin, the study is also tracking the effect of the hormone therapy on bone mass. The new combination product is currently in Phase I trials.
Alan Behunin or Eric Aguiar, M.D., of TheraTech, Inc., Tel: 801-588-6200.
By Laurie McCarthy