Importance of enterosalivary recirculationin paracetamol pharmacokinetics

PAULA SCHAIQUEVICH; ADA; MODESTO RUBIO

Biopharmaceutics and Drug Disposition

Wiley Interscience

Año: 2002 vol. 23 p. 245 - 249

1099-081X

The contribution of an enterosalivary recirculation (salivarysecretion-swallowed -reabsorption of drug from the gastrointestinal tract) to the values of the pharmacokinetic parameters of paracetamol was studied in a two-way crossover design. Five healthy volunteers took a tablet of paracetamol (500 mg) in two occasions separated by a washout period. The difference between the two treatments consissted of saliva that was allowed or not to be swallowed during the 4 h of study. No statistically signficant differences were found in teh values of the pharmacokinetic parameters between treatments. The half-life time calculated from salivary levels was similar to the values previously reported by other authors. The percent of the oral dose excreted in saliva during 4 h study was very low (0.1%). Secondary peaks appeared in 8 of 10 profiles. The lack of influence of salivary secretion on the pharmaockinetic parameters of paracetamol and the low percent secretd in this fluid suggests that enter-salivary recirculation is a possible physiological phenomenon undergoing after oral administration, but it is not one of the principal phenomenon that defines the pharmacokinetic of the drug. We confirm that working with salivary samples in pharmaockinetic studies of paracetamol is a useful tool.