5 vs 10-Minute Chewing of Caffeinated Gum: Plasma Caffeine Pharmacokinetics

This is a within-subject, repeated-measures, two-visit, fixed-sequence study comparing two chewing durations of caffeinated gum (5 minutes vs 10 minutes). Participants attend two visits on separate days with at least 48 hours between visits to minimize carryover effects. The order is fixed: the 5-minute chewing condition is completed at Visit 1 and the 10-minute chewing condition at Visit 2.

At each visit, participants receive approximately 300 mg of caffeine via commercially available caffeinated chewing gum (three pieces; about 100 mg per piece). Venous blood samples are collected to measure plasma caffeine concentration over time. Samples are obtained at baseline (0 minutes), during chewing (5 minutes in both conditions and 10 minutes only in the 10-minute condition), and after chewing at 30, 50, 60, 80, 90, 120, and 180 minutes. Plasma caffeine is quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

The plasma caffeine concentration-time profile is used to derive pharmacokinetic outcomes, including peak plasma caffeine concentration, time to peak concentration, exposure from 0 to 180 minutes, and the duration that plasma caffeine remains at or above 90% and 80% of the individual peak concentration.

The study was approved by the Ege University Faculty of Medicine Medical Research Ethics Committee, and written informed consent was obtained from all participants prior to participation.

Inclusion criteria

• Male, 18-35 years
• Good general health
• No regular use of medications or substances
• Habitual daily caffeine intake ≤300 mg/day

Exclusion criteria

• Habitual daily caffeine intake >300 mg/day
• Failure to participate in any study measurements
• Failure to comply with required test and measurement protocols
• Experiencing adverse effects from caffeine during the compliance period