QUANTIFICATION OF CAFFEINE AND ITS MAIN METABOLITE PARAXANTHINE FROM DRIED BLOOD SPOTS (DBS) AFTER DIFFERENT FORMS OF ORAL CAFFEINE ADMINISTRATION

INTRODUCTION: Caffeine is a widespread ergogenic aid used in mass sport as well as in competitive sport. To alter athletic performance, it is used in many forms: as caffeinated drinks, caffeine anhydrous or caffeinated chewing gums.Studies have already shown a difference in plasma pharmacokinetics after consumption of caffeinated chewing gum and caffeine capsules (Kamimori et al., 2002). Over the last years the number of caffeine containing supplements in diverse administration forms have significantly increased. Consequently, the aim of the study is to investigate their different mechanisms of action. For this purpose, the influence of five different administration forms on the caffeine and paraxanthine blood concentration were analyzed.METHODS: 200 mg caffeine in five application forms was administered to 16 healthy young adults in a randomized cross-over design:capsule, tablet, drinking ampule, chewing gum and pouches. Samples were taken in form of 20 μl Dried Blood spots (DBS) at 16 different points in time in a two-hour time frame after caffeine administration. Samples were analyzed by a validated UHPLC-MS/MS method. Area under the curve (AUC), maximum concentration (cmax), time to maximum concentration (tmax) and change from baseline to cmax (cmax) were calculated using Excel 2019 . Shapiro-Wilk test for normality of data, parametric and non-parametric tests were calculatedusing SPSS 28.RESULTS: Data evaluation show highly intra- and interindividual differences depending on baseline concentration and administration form. Classification of three groups based on baseline caffeine concentration were made. One-way ANOVA analysis revealed significant differences (p<.001) between group 1 baseline concentration < 1 μg/ml) and group 3 (baseline concentration > 10 μg/ml). Tukey post-hoc analysis showed a significantly increased cmax in three out of five administration forms and a significantly increased AUC in all administration forms for higher baseline concentration (group 3) (p < .05) .Total cmax is highest after tablet ingestion (405 ± 155μg/ml) and tmax is shortest after pouche administration (31 ± 19 min). Steadily increasing paraxanthine concentrations demonstrate a constant rise in metabolization rate of caffeine shortly after ingestion.CONCLUSION: The results of this study support recent findings that caffeine absorption and metabolism vary depending on administeredform of caffeine. It confirms that absorption is fastest, when already beginning through buccal mucosa. Baseline caffeine concentration significantly influences the rate of caffeine absorption and maximal caffeine concentration after the ingestion of 200mg caffeine.These findings should be taken into consideration whenever athletes use caffeine to enhance sports performance.
ReferencesKamimori, et al. (2002), The rate of absorption and relative bioavailability of caffeine administered in chewing gum versus capsules tonormal healthy volunteers. Int J. Pharm., 234(1), 159–167