“Vaporization as a ‘Smokeless’ Cannabis Delivery System”
Donald Abrams, M.D., University of California, San Francisco
(vaporization of cannabis) "The aim of this study was to evaluate the use of a vaporization system (the Volcano; VAPORMED® Inhalatoren; Tüttlingen, Germany) as a “smokeless” delivery system for inhaled cannabis. Because of concerns regarding the practicality and palatability of using cannabis cigarettes as a standard treatment, there has been an interest in developing alternative delivery systems. Participants were randomly assigned to receive low, medium, or high dose (1.7, 3.4, or 6.8% tetrahydrocannabinol) cannabis cigarettes delivered by smoking or by the vaporization
system on six study days.
"The full results of this study have been published in the journal Clinical Pharmacology & Therapeutics (Abrams, et al., 2007 – see reference list). Eighteen healthy volunteers were recruited to participate in the research. The analysis indicated that the blood levels of vaporized cannabis are similar to those of smoked cannabis over a six hour period. However, blood concentrations of THC at 30 and 60 minutes after inhalation were significantly higher in vaporized cannabis as compared to smoked cannabis. In addition, carbon monoxide levels were significantly reduced with vaporization compared with smoked cannabis. Fourteen participants preferred vaporization, 2 preferred smoking, and 2 reported no preference. In summary, vaporization of cannabis was found to be a safe mode of delivery, and participants had a preference for vaporization over smoking as a delivery system in this trial."

Source

Center for Medicinal Cannabis Research, "Report to the Legislature and Governor of the State of California presenting findings pursuant to SB847 which created the CMCR and provided state funding," University of California, (San Diego, CA: February 2010), p. 12.
http://cdc.coop/docs/neuropat…