Study of paracetamol 1-g oral solution bioavailability.

The aim of this work was to assess paracetamol bioavailability after administering 1 g in oral solution. Eighteen healthy volunteers were selected for this open-label study. A total of 15.4 ml of Gelocatil Oral Solution (Laboratorios Gelos, S.L.), corresponding to 1 g of paracetamol, were administered to fasting subjects. Blood samples were collected at 0 min, 10 min, 20 min, 30 min, 45 min, 1 h, 1.5 h, 2 h, 3 h, 4 h, 6 h, 8 h, 10 h and 12 h. Paracetamol plasma concentrations were determined by reverse-phase high-performance liquid chromatography. The study was conducted without deviations from protocol. Pharmacokinetic data from 18 subjects were allowed for estimating fast and high-paracetamol bioavailability: t(max) 20 min (10-45) [median (range)], C(max) 24. 3 mg/l (6.5) [mean (standard deviation)], AUC(0-t) 64.0 mg h/l (16.1) and AUC(0-00) 68.1 mg h/l (17.9). These results are comparable to those described for Gelocatil Oral Solution given at a 650 mg dose and for immediate release Gelocatil 650 mg tablets. Absorption speed was very fast, similar to that described for other oral-solution formulations, which provides an immediate onset of pain and fever relief. The results of this study show suitable bioavailability for 1 g Gelocatil Oral Solution, with fast-absorption speed that provides an immediate onset of pain and fever relief.