the effect on caffeine accumulation appears to be independent of the nature of the n3 substituent and its absence in rats given 1,3-disubstituted xanthines ( 1,3-dsx ) instead of 1,3,8-tsx suggests that the presence of the c8-methyl group in the latter compounds is responsible for the accumulation phenomenon .
C0006644
caffeine
C0043318
xanthines