Patch To Deliver Marijuana Chemicals

[Guest Urbanhog]

Patch To Deliver Marijuana Chemicals

 

Everyone's heard of medicated patches for quitting smoking or replacing hormones.

 

But a University of Kentucky pharmacy researcher is working to create a first-of-its- kind prescription patch to deliver marijuana -like chemicals to ease nausea and stimulate appetite in people with AIDS and cancer.

 

Three years ago, Audra Stinchcomb's patch idea earned the first funding -- $361,000 -- awarded to marijuana -related research by the American Cancer Society.

 

"This is pioneering work," said David Ringer, scientific program director for the American Cancer Society. "It's a very novel use of cannabinoids."

 

The patch would be a breakthrough because it could administer beneficial marijuana chemicals without the need for inhaling the illegal plant. Smoking marijuana for medicinal purposes is outlawed in most states.

 

Stinchcomb's patch will use synthetic cannabinoids -- active marijuana compounds created in a chemist's lab -- not stuff directly extracted from the illicit plant. Last year, Stinchcomb applied for a patent related to the technology.

 

"It's a very hot area of drug development," said Peter Crooks, a UK pharmacy professor who specializes in new drug discovery. "The potential is enormous."

 

Once initial studies are complete, human testing could follow. If all goes well, the patch could be commercially available in five years.

 

Cannabinoids have significant potential for pain treatment related to neuropathy, a common type of nerve damage, which isn't well controlled with current medications, Crooks said. The compounds also could be used for treatment of depression, Alzheimer's, Parkinson's disease and more.

 

"They're much safer as drugs," said Stinchcomb, 37, who arrived at UK in 2001 from the Albany College of Pharmacy in New York. "You never hear of people being stoned to death." Researchers think cannabinoids don't have the significant side effects -- dependency, nausea, vomiting -- that occur with morphine-based drugs now common in pain treatment.

 

Though not well known, a cannabis-based prescription capsule has been available in the United States for more than 15 years. Marinol (dronabinol), approved by the FDA in 1985, treats nausea, vomiting and severe loss of appetite from chemotherapy or AIDS.

 

"When this drug has been taken by capsule, it can have a good effect," Ringer said. "But if they can't keep the capsules down, it won't work."

 

Marinol is made from a synthetic form of THC, delta 9-tetrahydrocannabinol, a main intoxicating chemical in marijuana .

 

The natural compounds in marijuana are used as a sort of template by laboratory chemists to create synthetic cannabinoids, which are considered more controllable for medical use than plant extracts.

 

Researchers have found more than 400 chemicals in marijuana , about 60 of them cannabinoids, such as THC. Stinchcomb's three labs are evaluating about a dozen synthetic cannabinoids for possible use in the patch.

 

Cannabinoid research limited

 

Though this type of cannabinoid delivery may be new, medicines have long been derived from plants. It's estimated that about 25 percent of all U.S. prescription drugs are made from plant extracts or ingredients synthesized from plants. Among them are common pain drugs, including aspirin, morphine and codeine.

 

Despite tremendous interest from the pharmaceutical industry, academic researchers shy away from cannabinoid work, Crooks said.

 

"Researchers are scared to death of being looked at as 'the pot doctor,'" said Mary Lynn Mathre, a registered nurse, addictions specialist and organizer of the National Clinical Conference on Cannabis Therapeutics.

 

Research with marijuana -related compounds or any drug classified as a Schedule 1 controlled substance requires a government permit, inspection by the U.S. Drug Enforcement Administration, security checks of the facility and lab staff and other requirements. The red tape involved also discourages some researchers, Mathre said.

 

Still, cannabinoid research is becoming more common.

 

A THC-based rectal suppository is in development at the University of Mississippi, and researchers at Virginia Commonwealth University are looking into THC's potential to reduce dependence for people on long-term morphine therapy. Other researchers are developing inhalers, vaporizers and lozenges that are placed under the tongue.

 

Benefits of patches

 

Patches are popular because patients don't have to remember to take medication and the drug absorbs slowly into the body, reducing some side effects. Stinchcomb's specialty is transdermal medications, which are drugs that can be applied through the skin.

 

"This has some real potential for therapeutic application," said Richard Musty, executive director for the International Cannabinoid Research Society, which now has more than 200 member researchers. Stinchcomb's patch work has been presented at two of its annual conferences.

 

It is not as simple as placing a drug on the skin.

 

"The main challenge is the skin itself," Stinchcomb said. "The skin is designed to keep bad stuff out of the body."

 

She tests compounds to see how well they absorb into human skin. The compounds are applied to test skin patches -- leftovers from tummy tuck operations, which arrive on ice weekly from a government research tissue bank.

 

Compounds and patches will also be evaluated on the buttery skins of live, hairless guinea pigs and pigs.

 

"It's the best match to human skin," Stinchcomb said.

 

Patches eliminate the "first pass" effect. Medications applied through the skin aren't processed in the stomach, so less medication is needed and less is absorbed by the liver.

 

Less medication to the liver would be a significant benefit for two other Stinchcomb studies. She is formulating medicated patches to treat alcoholism, and alcoholism that occurs with nicotine addiction.

 

Naltrexone (ReVia) tablets were first used to treat heroin addiction, and since 1995 have been used to reduce alcohol cravings. Giving the medication by patch could help lower potential liver damage for a group already at high risk.

 

The two naltrexone studies earned research grants of about $2 million from the National Institutes of Health -- an incredible amount of funding for a young researcher, said Crooks. Crooks and Stinchcomb are collaborating on the naltrexone studies.

 

"She's going to be a star," Crooks said of Stinchcomb. "In five to 10 years, she'll be a key faculty member. I hope we are able to keep her."

 

Barbara Isaacs, Lexington Herald-Leader

(859) 231-3576 or 1-800-950-6397, Ext. 3576, or bisaacs@herald-leader.com.