Methods: Transdermal nicotine patches (Nicorette 15 mg.16 h-1) were administered to 7 healthy volunteers. Nicotine concentrations in gastric juice were monitored for 8 h via a naso-gastric tube and so was nicotine in saliva and plasma.
Results: Nicotine accumulated in gastric juice, the average concentration being 60.6-times higher than in plasma. In saliva, too, the concentration was higher than in plasma, the average ratio being 10.5. These results strongly suggested ion-trapping of nicotine base in the acidic gastric juice and possibly also in the acinar cells, followed by active secretion. It is hypothesised that accumulation in saliva occurs via a similar mechanism. Pretreatment with omeprazole did not increase the pH to a sufficiently high degree to test the hypothesis that the accumulation of nicotine in gastric juice was pH dependent.
Conclusion: Transdermal administration of nicotine produced a high intragastric concentration. The clinical consequence of this effect of long-term nicotine replacement therapy during smoking cessation is unclear.