title: High-performance liquid chromatography of xanthines. Effects of N-methyl and C-8 hydroxyl substitution on the retention times.
abstract: The capacity factors of 26 xanthine derivatives were measured by reversed-phase high-performance liquid chromatography. N-Methyl substitution increased the capacity factor and the related lipid solubility. The descending order of the increase in capacity factor by the N-methyl group is: N-1 methyl greater than N-3 methyl greater than N-7 methyl greater than N-9 methyl. C-8 hydroxylation reduces the capacity factor in the xanthines. The reduction factor is 3.34 in xanthines with N-3 methyl substitution, 2.41 in xanthines with N-1 and/or N-7 methyl substitution and 1.68 in xanthines with N-9 methyl substitution.
authors.affiliation: Department of Clinical Pharmacy, Saint Radboud Hospital, University of Nijmegen, The Netherlands.
authors.forename: T B
authors.initials: TB
authors.lastname: Vree
authors.forename: L
authors.initials: L
authors.lastname: Riemens
authors.forename: P M
authors.initials: PM
authors.lastname: Koopman-Kimenai
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D006900:Hydroxylation; D008745:Methylation; D012995:Solubility; D014970:Xanthines / Q000032:analysis*
chemical_list: D014970:Xanthines