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Diurnal effect on caffeine clearance
M Hashiguchi1, A Fujimura, K Ohashi
1Department of Clinical Pharmacology, Medical School of Oita, Japan.
Journal of Clinical Pharmacology
|February 1, 1992
Summary
Caffeine clearance in saliva is unaffected by administration time. This suggests that plasma caffeine clearance may also remain consistent, regardless of whether caffeine is consumed during the day or night.
Area of Science:
- Pharmacokinetics
- Chronopharmacology
Background:
- Caffeine is a widely consumed stimulant with known pharmacokinetic properties.
- Understanding how the timing of caffeine intake affects its metabolism is crucial for accurate dosing and predicting its effects.
Purpose of the Study:
- To investigate whether the time of day (day vs. night) influences caffeine clearance in saliva.
- To explore potential implications for plasma caffeine clearance based on urinary metabolite ratios.
Main Methods:
- A crossover study involving nine healthy subjects who received 300 mg of caffeine orally.
- Saliva samples were collected at multiple time points (0.5 to 8 hours) post-administration.
- Urine was collected for 8 hours to analyze metabolite ratios.
Main Results:
- No significant differences were found in caffeine clearance rates in saliva between the day and night trials.
- Urinary molar ratios of key caffeine metabolites (AFMU + 1X + 1U/17U) did not differ significantly between the two administration times.
Conclusions:
- Caffeine clearance in saliva is not significantly affected by the time of oral administration.
- These findings suggest that plasma caffeine clearance may also be independent of dosing time, as indicated by stable urinary metabolite profiles.