Correlation of serum and salivary levels of pentoxifylline.

Twelve healthy volunteers were treated with 400 mg pentoxifylline at 1000 and 2200 hours in a randomized crossover design with a washout period of 1 week. Serum and saliva samples were analyzed for unchanged pentoxifylline by high-performance liquid chromatography. Saliva to serum ratios and pharmacokinetic parameters of pentoxifylline were calculated. Significant (p < 0.05) correlation between serum and salivary levels of pentoxifylline was observed for the treatments at 1000 and 2200 hours. Although the mean saliva/serum ratios of pentoxifylline in the postabsorption phase were found to be higher for the 2200-hour treatment than the 1000-hour treatment, this difference was not statistically significant (p > 0.05). Further, no significant (p > 0.05) difference was noted between the mean pharmacokinetic parameters of pentoxifylline whether computed through serum or through salivary levels for either treatment. Hence, saliva can be used in place of serum/plasma in pharmacokinetic and interaction studies of pentoxifylline.