the order of potency was : 1,3-diethyl-8-phenylxanthine greater than 8-phenyl-theophylline greater than ibmx = 8-p-sulphophenyltheophylline = verrophylline greater than theophylline greater than caffeine greater than enprofylline greater than theobromine greater than pentoxiphylline .
C0000096
ibmx
C0039771
theophylline