At the Noven Pharmaceuticals plant in southwest Miami, scientists and technicians use highly specialized machinery to blend prescription medications and adhesives to make layered transdermal patches that release precise quantities of drugs over time after being applied to a patient’s skin.

Noven, a subsidiary of Japan’s Hisamitsu Pharmaceutical, has about 700 employees nationwide and ranks as a relatively small player among pharma giants. Nonetheless, the company, a leading research and development center for medicinal patches, produces a line of specialty pharmaceuticals and is the U.S. market leader in sales of estrogen patches for women.

“By industry standards, Noven is a small company,” said Jeffrey F. Eisenberg, Noven’s Miami-based president and CEO. “But we have a line of specialized products that competes successfully in the U.S. and overseas. We are experts in developing transdermal patches and produce other pharmaceutical products.”

In one key market — estrogen patches for women — Noven holds about a 68 percent share, he added. And the company has a robust research and development department in Miami at work on a variety of new drugs.

Medications may be delivered to patients orally, via injection or through transdermal patches, which can administer drugs slowly over an extended period of time. While Noven makes products other than medicinal patches, it devotes an important share of resources to transdermal patch technology.

“We have a talented group of scientists who are at the forefront of this specialty,” Eisenberg said. “We have M.D.s, PhDs in biology and chemistry and chemical engineers who specialize in pressure-sensitive adhesives and polymer chemistry.”

Noven has won more than 30 U.S. and 100 international patents and is developing several new drugs. The company recently announced it is making progress on studies to evaluate a new, amphetamine-based transdermal patch for treating Attention Deficit Hyperactivity Disorder (ADHD) in children and adolescents. Currently, there is no such patch approved for use with ADHD, the company said.

Noven also has applied to the U.S. Food & Drug Administration for approval of a new oral, non-hormonal medication to treat menopausal hot flashes.

Making patches is a complex process that requires the design and development of an ideal combination of drug, adhesive and backing, Eisenberg said. Patches must be formulated so that they will deliver a safe and effective dose of medication over a period of time and adhere to the skin as required.

At the Noven patch facility, which has the capacity for making 500 million patches per year, active drug compounds are mixed with custom adhesives in large, specialized kettles. The mix of drug and adhesive is then applied to sheets of release liner material under very precise tolerances. Noven removes a blending solvent from the compound and applies the backing material, making a three-layer patch. Laminate rolls subsequently are sent to punching, pouching and packing machines (Patches are punched into different sizes.). All of this occurs under strict quality control procedures and is not open to the public.

Noven was founded in 1987 by Steven Sablotsky, a chemical engineer, who had worked for another pharmaceutical firm and was an expert in transdermal patches. Noven went public in 1988 and operated as a publicly-traded company until it was taken over in 2009 by Hisamitsu, a Japanese pharmaceutical company that also manufactures and markets transdermal patches. (Salonpas, an over-the-counter analgesic patch widely advertised in South Florida, is made by Hisamitsu.)