GLC determination of meperidinic and normeperidinic acids in urine

A GLC procedure for the determination of meperidinic and normeperidinic acids in human urine is described. After the extraction of any interfering meperidine or normeperidine, the urine samples are dried and the acids are reesterified using ethanol-sulfuric acid. The resulting meperidine and normeperidine are then extracted and quantified. With this method, the urinary excretion of these metabolites was followed in five subjects who received a single meperidine dose of 36 mg/m2 im. This method represents an improvement over the previously described methods for meperidinic and normeperidinic acids and can be applied to clinical situations.