Comparison of oral bioavailability of acetaminophen one and two glass water administration in healthy volunteers

Background and objective: Acetaminophen as an analgesic and antipyretic drug has good absorption in the gastrointestinal tract.Bioavailability is a measure of the amount of an administered dose that reaches the bloodstream. It is known that the efficacy of a drug depends on its dosage form and route of administration. The purpose of this study was to compare the oral bioavailability of acetaminophen one and two glass water administration in healthy volunteers. Method and materials: This study was approved by the Ethics Committee of Babol University of Medical Sciences (Babol, Iran). In this clinical trial study, we included 20 healthy volunteers. A single dose of acetaminophen (a 500 mg tablet) was administered using the imported acetaminophen with 1 glass water and acetaminophen with 2 glass water in the first and second groups, respectively. Exclusion criteria included taking any medication in the previous two days. Blood samples were taken at 0, 1, 2, 4 and 8-hour intervals after receiving the dose. Acetaminophen blood levels were measured using the HPLC method. The HPLC method used the following specifications: C18 column (4.6 mm x 25 mm), UV detector wavelength of 240 nm and flow rate 1ml/min. Data were fit in a one-compartment PK model using P-Pharm 1.5 software and analyzed under statistical tests.Finding: Pharmacokinetic (PK) data analysis from the two groups showed that the half-life of acetaminophen was 140.72 min in the group 1 and 126.29 min for group 2; Statistically, no significant differences between this groups in PK parameters were recorded as we compared (p> 0.05). Significant differences in mean of acetaminophen concentrations at 1h after taking the drug between groups 1 and 2 were Statistically recorded (p < 0.05). The maximum concentrations of acetaminophen in blood samples were measured 10.918±3.09 at 1h after taking the drug in group 2. The maximum concentrations of acetaminophen in blood samples were measured 8.738 ±4.49 at 2h after taking the drug in group 1. The area under the blood levels curve were 47.04 and 48.05μgmin/ml in group 1 and 2. Conclusion: According to the results, in the tablet group with 2 glass water, acetaminophen concentration achieves the maximum levels in less time compared with tablet group with 1 glass water.Studies have shown that more water consumption causes the drug to transit faster from stomach to small intestine, therefore we suggest that more water should be administered in cases of pain and fever to achieve quick drug efficacy.

کلیدواژه ها:

Pharmacokinetics ، Acetaminophen ، HPLC ، Kinetic Modeling