title: Reversed-phase liquid chromatographic investigation of UV-absorbing low-molecular-weight compounds in saliva.
abstract: The reversed-phase mode of high-performance liquid chromatography was used to determine the intra- and inter-individual levels of UV-absorbing low-molecular-weight compounds in saliva. Many of the compounds known to occur in serum were also found in saliva; however, concentrations in saliva are lower. Both the intra- and inter-individual levels of these compounds vary significantly; in most cases, the inter-individual variance is 2-3 times the intra-individual variance. Caffeine and its metabolites in saliva are also reported. A greater number of metabolites were found in the saliva of habitual coffee drinkers. After caffeine was administered orally, paraxanthine, theobromine, theophylline, 1-methylxanthine, and 1-methyluric acid were found in the saliva of an individual who did not drink coffee regularly. In this subject, the serum half-life for caffeine was 3.49 h and the saliva half-life was 3.27 h. The half-life of caffeine in an habitual coffee drinker who had refrained from caffeine products for four days was 4.39 h.
mesh_terms: D002110:Caffeine / Q000097:blood / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D006801:Humans; D008970:Molecular Weight; D012463:Saliva / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet; D013805:Theobromine / Q000032:analysis; D013806:Theophylline / Q000032:analysis; D013997:Time Factors
chemical_list: D002110:Caffeine; D013806:Theophylline; D013805:Theobromine; C021183:1,7-dimethylxanthine