ABSTRACT
Aminopyrine and its metabolites, including 3-hydroxymethyl-2-methyl-4-dimethylamino-1-phenyl-3-pyrazoline-5-one which is a hydroxylated metabolite of aminopyrine, were separated on a reversed-phase (C8) Radial-Pak column using a mobile phase of methanol-triethylamine-water (30:1:69) adjusted to pH 5.40 with acetic acid. Detection of the peak was performed by an ultraviolet detector at 254 nm. By the rapid and simple method, aminopyrine hydroxylation as well as aminopyrine N-demethylation in liver microsomes can be examined simultaneously.
Subject(s)
Aminopyrine/metabolism , Microsomes, Liver/metabolism , Pyrazolones , Aminopyrine/analogs & derivatives , Aminopyrine/isolation & purification , Ampyrone/isolation & purification , Animals , Biotransformation , Chromatography, High Pressure Liquid , Dipyrone/analogs & derivatives , Dipyrone/isolation & purification , Hydroxylation , Methylation , Microsomes, Liver/enzymology , RatsABSTRACT
Thin-layer chromatographic (TLC) methods were developed for pharmacokinetic studies of major metamizole metabolites in serum and urine. These methods proved practicable, selective, accurate and sensitive with detection limits as follows: 4-methylaminoantipyrine 0.6 micrograms/ml serum and 2.0 micrograms/ml urine; 4-aminoantipyrine 0.16 micrograms/ml serum and 1.0 micrograms/ml urine; 4-acetylaminoantipyrine 0.14 micrograms/ml serum and 0.6 micrograms/ml urine; 4-formylaminoantipyrine 0.12 micrograms/ml serum and 1.0 micrograms/ml urine. Samples of 250 microliter suffice for TLC analysis. Following chromatographic separation, detection is performed in the ultraviolet range at 265 nm. Serum and urine levels were determined following a single oral dose of 1 g of metamizole sodium to eight volunteers. These results were compared with those following an accidental overdose of 49 g.
Subject(s)
Aminopyrine/analogs & derivatives , Dipyrone/metabolism , Pyrazolones , Adolescent , Aminopyrine/isolation & purification , Ampyrone/analogs & derivatives , Ampyrone/isolation & purification , Chromatography, Thin Layer , Dipyrone/analogs & derivatives , Dipyrone/isolation & purification , Dipyrone/poisoning , Female , Half-Life , Humans , KineticsABSTRACT
A simple reversed-phase high-performance liquid chromatographic pre-column technique for investigation of drug metabolism is described. This rapid method circumvents the "classical" sample purification via extraction by direct purification and enrichment of the sample on the pre-column. Almost 100% recovery of a drug (aminopyrine) and its metabolites from biological fluids is achieved. This is in strong contrast to "classical" sample preparation which allows a recovery of 30-100% depending on the polarity of the investigated compound. The procedure described has been successfully applied to the investigation of the metabolic pattern of aminopyrine in rat plasma and cell incubation media.
