ANNAPOLIS, Md. (AP) — With Maryland set to make medical marijuana available within weeks, two companies have formed a partnership to study how well vapor-inhalation devices work for patients.

Curio Wellness, of Lutherville, and Wellness Institute of Maryland, of Frederick, will conduct a research-and-development study of cannabis oil-filled vapor inhalation devices, the state health department announced Friday. The devices, also known as vape pens, can be used to vaporize marijuana, or heat it without burning it.

The amount of medical marijuana products are expected to be low at first, the health department said, compared to inventories of products in other state's that allow it. It could take licensed growers and dispensaries several months to reach full inventory, after becoming operational.

"It's also worth noting that, for this study, only the Wellness Institute of Maryland dispensary will be providing products to patients who were pre-selected by the companies," said Brian Lopez, chairman of Maryland's medical marijuana commission. "But all licensed and operational dispensaries are expected to have products available by early December."

So far, 14 marijuana growers and 12 processors have been licensed in Maryland. Six dispensaries also have been licensed.

Medical marijuana will be available in the state for any condition that is severe in which other medical treatments have been ineffective, and if the symptoms "reasonably can be expected to be relieved" by marijuana. Patients with a chronic or debilitating medical condition that causes severe appetite loss, severe or chronic pain, severe nausea, seizures or severe muscle spasms also can have access, as well as people with glaucoma or post-traumatic stress disorder.

Maryland will allow not only physicians but nurse practitioners, dentists, podiatrists and nurse midwives to certify patients as eligible to receive marijuana.

Maryland's medical marijuana program has been delayed by setbacks. The state first approved it in 2013, but the effort stalled because it required academic medical centers to run the programs, and none stepped forward. The law was changed in 2014 to allow doctors certified by a state commission to recommend marijuana for patients with debilitating, chronic or severe illnesses.