PARACETAMOL ABSORPTION FROM DIFFERENT SITES IN THE HUMAN SMALL-INTESTINE

Site-specificity in the small intestinal absorption of paracetamol was investigated using a segmental intestinal steady state perfusion tech nique (triple-lumen tubing system) combined with simultaneous measurem ents of serum drug concentrations. Dissolved paracetamol was perfused over 160 min into different parts of the small intestine (65-210 cm be yond the teeth). Each of the four healthy subjects was studied twice w ith a proximal and a more distal site of perfusion. Serum drug concent rations were similar after proximal and distal perfusions. Mean drug a bsorption rates calculated from intestinal aspirate concentrations wer e similar in both parts of the intestine-proximal: 869 mu g 30 cm(-1) min(-1) (95% CI: 659-1079) vs distal: 941 mu g 30 cm(-1) min(-1) (794- 1088). The absorption rate was related directly to the amount of parac etamol perfused per unit time as well as to the rate of transmucosal w ater fluxes.