Gastric emptying of liquids is delayed by co-ingesting solids: a study using salivary paracetamol concentrations

Abstract

Background: Paracetamol concentrations in plasma, a frequently used index of gastric emptying (GE) of liquids, are closely correlated with those in saliva. GE of liquids is delayed by co-ingesting solids. No researchers have used salivary paracetamol concentrations to show this phenomenon. The aim of this study was to elucidate whether salivary paracetamol concentrations can detect the food-induced delay in liquid GE.

Methods: Paracetamol absorption was measured twice in five healthy male volunteers. Following an overnight fast, they received 10 mg/kg paracetamol in 200 ml water alone on one occasion, and received this solution after consuming a 400 kcal-containing cookie on another occasion. After thorough rinsing of the month, 1 ml saliva was obtained, simultaneously with 2 ml blood, at 0, 0.25, 0.5, 0.75, 1.0, 2.0, 3.0, 4.0, and 6.0 h after paracetamol intake. The peak concentration (C(max)), the time to C(max) (t(max)), the area under the curve (AUC), and C(max)/AUC in plasma were calculated. Salivary C(max) and t(max) were also determined.

Results: Plasma C(max) and AUC were not significantly different between the two occasions. In contrast, significant differences in plasma t(max) and C(max)/AUC ( P < 0.05) established the food-induced delay in GE. Salivary t(max) could detect the delayed GE, whereas salivary C(max) could not.

Conclusions: Salivary t(max) can document the solid meal-induced delay in liquid GE.