Identification And Quantification Of Verapamil In Blood And Urine

Purpose: To adapt and validate an HPLC method for verapamil determination in blood and urine samples.Materials/Methods: Identification of verapamil and its metabolites was made by means of gas -chromatography, using Agilent 7890B/5977A GC-MS system featuring a DB-1701 column. Quantification was done by means of liquid chromatography on Agilent 1260 series HPLC, equipped with Zorbax Extend-C18 column and both diode-array and fluorescent detection modules. Blood and urine specimens were taken from patients of the Clinic for intensive treatment of acute intoxications and toxicoallergies within the course of their treatment.Results: GC-MS identification of verapamil and its metabolites was carried out after simple liquid-liquid extraction of samples without further chemical derivatization. Adapted HPLC method for quantification require isocratic conditions and mobile phase, consisted of phosphate buffer (pH 2.7; 10 mM) containing 1.5 ml L-1 triethylamine - acetonitrile (70:30, v/v) at 20 degrees C, flow rate 1.0 mL/min and FLD detection (excitation: 203 nm, emission: 320 nm). The method was demonstrated to be linear within the whole region of interest (4.6-4600 ng mL(-1)) with excellent accuracy (101.7-102.2%) and inter day precision (5.81%) as well as good analytical recovery (81.2%) and LOQ (7.0 ng mL(-1)).Conclusion: A precise and easy to use method for verapamil detection and quantification is developed. The method is applicable as a routine procedure in the Laboratory of analytical toxicology for both diagnosis clarification in cases of acute intoxications and therapeutic drug monitoring.