Biological Response after 14-Day Cannabidiol and Propylene Glycol Inhalation in Sprague-Dawley Rats.

Area of Science:

• Toxicology
• Cannabinoid Research
• Respiratory Health

Background:

• Cannabidiol (CBD) is a popular phytocannabinoid with potential therapeutic uses.
• Consumption is mainly via ingestion or inhalation, but inhalation toxicology is understudied.
• Previous research focused on oral CBD toxicity, leaving inhalation effects largely unknown.

Purpose of the Study:

• To investigate the toxicological effects of inhaled cannabidiol (CBD) in Sprague Dawley rats.
• To evaluate dose-response relationships for CBD inhalation at high concentrations.
• To determine the safety margin of inhaled CBD relevant to typical consumer product usage.

Main Methods:

• CBD formulated in propylene glycol was aerosolized and inhaled by rats (nose-only exposure).
• Rats were exposed to varying concentrations and durations, with doses significantly exceeding typical human consumption.
• Biological responses were assessed through clinical signs, blood chemistry, hematology, organ weights, and histopathology.

Main Results:

• Nasal inflammatory and necrotic responses were observed at the highest inhaled CBD doses.
• Limited laryngeal and lung findings occurred, primarily at higher exposure levels.
• No histological changes were found in organs outside the respiratory tract.

Conclusions:

• High-dose inhaled CBD can induce dose-dependent histological changes in the respiratory tract, particularly the nose.
• A substantial safety margin exists for inhaled CBD at doses relevant to over-the-counter vape products.
• The no observable adverse effect levels for nasal and lung tissues were determined to be 2.8 and 10.6 mg/kg CBD, respectively.