Regional deposition of inhaled 11C-nicotine vapor in the human airway as visualized by positron emission tomography

Clin Pharmacol Ther. 1995 Mar;57(3):309-17. doi: 10.1016/0009-9236(95)90156-6.


The deposition of 11C-nicotine in the respiratory tract from a nicotine vapor inhaler was studied by means of positron emission tomography (PET) in an intrasubject comparison of six healthy smokers using two modes of inhalation: one with shallow, frequent inhalations ("buccal mode") and one with deep inhalations ("pulmonary mode"). An average of 15% of the radioactivity was released from the vapor inhaler after 5 minutes of inhalation. Approximately 45% of the dose released was found in the oral cavity. A significant amount of radioactivity, 10%, was observed in the esophagus, suggesting transfer of a major fraction of the dose to the stomach. Only a minor fraction, 5%, was found in the lungs, followed by 2% in the bronchi and 1% in the trachea. The deposition in the oral cavity closely followed a linear pattern during the 5 minutes of inhalation and was followed by a rapid elimination from the oral cavity, with an average half-life of 18 minutes. Only 8% of the dose released remained in the oral cavity 45 minutes after the end of inhalation. On the other hand, the dose fraction of about 14% distributed into the body tissue compartment at the end of inhalation had risen to 60% at that late time point. No statistically or clinically important differences were observed between the buccal and the pulmonary mode of inhalation in either deposition pattern or elimination rates.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Inhalation
  • Adult
  • Carbon Radioisotopes
  • Humans
  • Male
  • Middle Aged
  • Mouth / diagnostic imaging*
  • Nebulizers and Vaporizers
  • Nicotine / administration & dosage*
  • Nicotine / pharmacokinetics*
  • Respiratory System / diagnostic imaging*
  • Tomography, Emission-Computed*


  • Carbon Radioisotopes
  • Nicotine