Acetaminophen In Samples Research Articles

A novel sensor based on electrochemical polymerization of diglycolic acid for determination of acetaminophen

Diglycolic acid (DA) polymer was coated on glassy carbon (GC) electrode by cyclic voltammetry (CV) technique for the first time. The electrochemical performances of the modified electrode were investigated by CV and electrochemical impedance (EIS). The obtained electrode showed an excellent electrocatalytic activity for the oxidation of acetaminophen (ACOP). A couple of well-defined reversible electrochemical redox peaks were observed on the ploy(DA)/GC electrode in ACOP solution. Compared with bare GC electrode, the oxidation peak potential of ACOP on ploy(DA)/GC electrode moved from 0.289V to 0.220V. Meanwhile, the oxidation peak current was much higher on the modified electrode than that on the bare GC electrode, indicating DA polymer modified electrode possessed excellent performance for the oxidation of ACOP. This kind of capability of the modified electrode can be enlisted for the highly sensitive and selective determination of ACOP. Under the optimized conditions, a wide linear range from 2×10−8 to 5.0×10−4M with a correlation coefficient 0.9995 was obtained. The detection limit was 6.7×10−9M (at the ratio of signal to noise, S/N=3:1). The modified electrode also exhibited very good stability and reproducibility for the detection of ACOP. The established method was applied to the determination of ACOP in samples. An average recovery of 100.1% was achieved. These results indicated that this method was reliable for determining ACOP.

The Electrochemical Behavior of Acetaminophen on Multi‐Walled Carbon Nanotubes Modified Electrode and Its Analytical Application

A multi‐walled carbon nanotubes modified glassy carbon electrode (MWNTs/GCE) was fabricated, and the electrochemical behaviors of acetaminophen (ACOP) were investigated on the MWNTs/GCE. The results showed that MWNTs exhibited excellent electrocatalytic effects on the reaction of ACOP by accelerating the electron transfer rate. Cyclic voltammetry (CV) was used to explore the electrochemical redox mechanism of ACOP on the MWNTs/GCE and differential pulse voltammetry (DPV) was taken to determine ACOP in samples, respectively. The results showed that the oxidative peak currents were linear with the concentration of ACOP in the range of 4.0×10−7–1.5×10−4 mol l−1 with the detection limit 1.2×10−7 mol l−1. The MWNTs/GCE showed satisfactory stability, selectivity, and it can be used to quantify ACOP in effervescent dosage real samples.

Kinetics of acetaminophen absorption and gastric emptying in man.

Eight healthy male volunteers ingested an aqueous solution containing acetaminophen (20 mg/kg) and a nonabsorbable isotopic marker. The concentrations of unconjugated acetaminophen in samples of blood plasma taken at frequent intervals were measured by gas-liquid chromatography. The data points followed a smooth curve in most cases and were fitted to the classical two-compartment pharmacokinetic model to obtain KA, the apparent first-order rate constant for absorption from the gastrointestinal tract. Gastric emptying was measured simultaneously from serial scintiscans of the subject's abdomen. The subjects were also studied after intramuscular injection of meperidine (150 mg) and pentazocine (60 mg) with and without naloxone (1.2 mg). The acetaminophen absorption curves and gastric emptying patterns were consistent with negligible absorption from the stomach. A new model is proposed in which the conventional single compartment used to represent the gastrointestinal tract is replaced by two compartments: one represents the stomach and the other the small intestine, from which absorption occurs rapidly. Pharmacokinetic analysis using this model showed good agreement in all cases, and provided an estimate of KA, the first-order rate constant for drug transfer from the intestinal lumen into the systemic circulation. The mean half-time for transfer was 6.8 +/- 0.9 min. As expected, KA was greater than KG (the first-order rate constant for gastric emptying), showing that gastric emptying was rate-limiting in the absorption of acetaminophen. The value of KA was greater than KA and the two were not related. The value of KA was not equal to KG in most studies because gastric emptying was not a single exponential process.