The invention relates to a novel injectable liquid formulation of paracetamol, comprising an aqueous solvent, a buffer agent with a pKa between 4.5 and 6.5, an isotonic agent and the dimer of paracetamol of formula (I), a method for preparation of said formulation and the use of said dimer for the stabilisation of a liquid paracetamol pharmaceutical formulation.
Enzyme Immobilized Magnetic Nanoparticles for In-Line Capillary Electrophoresis and Drug Biotransformation Studies: Application to Paracetamol
作者:Donghui Yu、Pierre Van Antwerpen、Stephanie Patris、Bertrand Blankert、Jean-Michel Kauffmann
DOI:10.2174/138620710791516058
日期:2010.7.1
Enzyme Immobilized Magnetic Nanoparticles (EMNPs) were injected and magnetically retained, as a microreactor, in the capillary of a capillary electrophoresis (CE) setup with UV detection. The enzyme horseradish peroxidase (HRP) was chemically immobilized onto commercially available magnetic 300 nm diameter nanoparticles. Paracetamol (acetaminophen: N-acetyl-p-aminophenol), a common analgesic drug, was used as model drug compound. The enzymatic reaction was studied in-line by CE in 12.5 mM phosphate buffer pH 7.4 containing 20 mg/ml sulfated-β- cyclodextrin and 0.1 mM hydrogen peroxide. By means of the developed setup, the apparent Michaelis Menten constant between HRP and acetaminophen (APAP) was determined as Km app = 53±5 μM. This approach was found to be of interest for enzyme kinetics studies with short time resolution condition. Based on our results and from the literature data, it was possible to infer that the in-line generated product was an APAP dimer. Higher enzyme immobilized beads loading in the CE setup generated the APAP dimer with two additional minor peaks likely attributing to APAP trimer and tetramer. N-acetyl- p-benzoquinone imine (NAPQI) was not generated during APAP short time migration through the in-line microreactor.