Validation of an analytical method for the determination in serum of psychotropic drugs by High-Performance Liquid Chromatography with Diode Array Detection

Background : Inter-individual variability in clinical response to psychotropic drugs remains problematic in management of mental illnesses. The patients differ in their ability to absorb, distribute, metabolize and eliminate drugs due to genetic peculiarities, concurrent disease, age, or concomitant medication Methods : A simple and sensitive high performance liquid chromatography method with ultraviolet  detection was validated for the determination of 27 psychotropic drugs in serum. The analysis by   High-Performance Liquid Chromatography (HPLC) was performed on serum spiked with analyte(s), and prazepam was used as an internal standard. To get validation parameters, analytical results were processed based upon the total error concept using Enoval software. Results : The validated method was linear over the tested dosing intervals with a coefficient of  determination of at least 0.99 for all molecules. The relative standard deviation (%-RSD) and bias were less than 15 % for all validation standards and the recovery varied between 92.7 % and 112.9 %. The accuracy of the method was demonstrated over the used dosing intervals. Conclusion : The method is suitable for both therapeutic drug monitoring and confirmation of drug  poisoning, except for haloperidol, flupentixol and zuclopenthixol where it is only applicable for the  confirmation of intoxication. Key words : Psychotropic drugs, serum, validation, HPLC-DAD