Vaporization of Cannabinoids: a Preferable Drug Delivery Route

Tod H. Mikuriya, M.D.

Oral vs Inhaled

While cannabis used medicinally has generally utilized the oral route, certain difficulties have been recognized since its introduction to western medicine by O'Shaughnessey in 1839. The most common entry in the Surgeon General's List, 19th century precursor to the Indicus Medicus described overdose. While not physically harmful, the mental effects were alarming.

While the oral cannabis ingestion using gradual upward titration may take days, oral cannabis' absorbtion rates vary, depending on motility and contents of the gastrointestinal tract. Inhaled cannabis by contrast produces much more rapid onset of effect (within minutes compared with hours), reliable effect, and accurate autotitration.

The current use of cigarette or pipe for the inhaling of cannabinoids is recognized as delivering numerous irritants and possible carcinogens along with the desired active principles to the tracheobronchial tree and oral cavity. Vaporization separates out the more therapeutic chemical components from the crude plant or resin impurities and breakdown products of pyrrolysis.

The vaporization temperature range is significantly below the flash point and pyrrolytic temperature of cannabinoids and non-cannabinoid components of crude cannabis.

Table 1

Some Chemical Constituents of Cannabis and their Vaporization Temperatures*

Compound Boiling Point

Degrees Centigrade Degrees Fahrenheit
Tetrahydrocannabinols 155-157 311-314.6
Cannabinols 185 365
Cannabidiols 187-190 368.6-374.0

There are some 421 identified compounds in cannabis, 61 of which are cannabinoids. All of these compounds are pyrrolyzed into numerous degradation products which are delivered to the respiratory tract through the process of smoking.**

Any mitigation of irritation to the oral cavity and tracheobroncheal tree in the delivery of active principles of cannabis- especially in the chronic marijuana user would be inherently safer. For the immunocompromised, debilitated, or in respiratory distress possibly life saving.

A program to study the physical and therapeutic properties including asthma which would utilize the therapeutic properties of the drug without the drawback of the irritation to the lungs.

Systematic evaluation of specific vaporization temperature ranges is required to better differentiate and characterize the optimal combinations of cannabinoids for different symptoms and conditions.

Draft 4

12/16/93

*Merck Index Eighth Edition 1968

**Turner, Marijuana and Health Report of a Study by a Committee of the Institute of Medicine National Academy Press, Washington DC 1982 page 14

Addendum: the latest edition of the Merck Index 1989 lists the boiling point of delta 1,9 Tetrahydrocannabinol as 200 degrees centigrade.