Προσδιορισμός του αντικαταθλιπτικού φαρμάκου σερτραλίνη και του κύριου μεταβολίτη αυτής σε βιολογικά υγρά με φασματομετρία μάζας: εφαρμογές στην κλινική και δικαστική τοξικολογία

Abstract

Sertraline [(1S,4S)-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-N-methyl-1-naphthyl amine] is a selective serotonin reuptake inhibitors (SSRIs). It is considered to be safe, effective and with well-tolerated adverse effects due to its highly specific affinity to central serotonin uptake sites. It has a wide therapeutic range and shows minimal side effects. Sertraline is used therapeutically mainly to treat the symptoms of depression and anxiety. It is also prescribed for the treatment of obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), premenstrual dysphoric disorder (PMDD), panic disorder (PD) and social phobia/ anxiety disorder. Sertraline is completely, but slowly, absorbed from the gut with a time to peak plasma concentration (Tmax) of 6-8 h, and undergoes extensive first–pass metabolism by the action of different cytochrome subtypes to form desmethyl-sertraline, an active metabolite with longer half-life. Due to its extensive metabolism and its wide distribution to tissues (Vd exceeds 20L/Kg), the plasma concentration of sertraline is very low in humans. At the therapeutic dose of 50 mg/day, the plasma concentration does not exceed 15 κg/L and its terminal half-life in healthy volunteers was reported ranging from 22-32 h. The widespread use of sertraline and its involvement in deliberate or accidental cases of self-poisoning in combination with Therapeutic Drug Monitoring (TDM) requirements led to the development of a rapid, simple, sensitive and specific analytical method for the determination of sertraline in blood by GC-MS. Furthermore, measuring of blood or plasma sertraline concentrations is of great importance in the areas of Clinical and Forensic Toxicology, like in suicide or driving under the influence of drugs cases. TDM is of critical importance in situations where patients under treatment do not respond as expected, in cases of drug interactions with co-medication either with inhibitors or inducers of CYP 450, non-compliance, and in patients at risk, such as elderly, with liver impairment or poor metabolisers. Monitoring of sertraline and its metabolite is of great importance for therapy optimization and dose adjustment, considering the interindividual variability of drug metabolism. The aim of our study was the development, optimization and validation of a new simple, sensitive and rapid method, based on GC/MS for the identification and quantification of sertraline and its major metabolite desmethyl-sertraline in whole blood. This method could be applied in routine toxicological analysis during investigation of clinical and forensic cases. Optimization of the derivatization procedure, Chromatographic conditions and the extraction were performed. SPE using a Bond Elut Certify column, mixed mode sorbent, and derivatization with acylation, HFBA were chosen for the study that allowed the specific and sensitive determination of sertraline and desmethyl-sertraline by GC/MS. Validation of the method was performed by conducting a series of experiments using the specific conditions of the method and the same type of matrix as the intended samples. The following criteria were used to evaluate the GC/MS method: selectivity, specificity, limit of detection (LOD), limit of quantification (LOQ), linearity, precision, accuracy, recovery, robustness and stability according to international criteria. The lack of the interference from endogenous blood compounds (selectivity) was observed and the method has proven to be quite selective. It shows high sensitivity, the limits of detection and quantification for both sertraline and desmethyl-sertraline were 0.30 and 1.00 κg/L, respectively. The calibration curves were linear within the dynamic range of each analyte (1.00-500.0 κg/L) with a correlation coefficient (R2) exceeding 0.991 for both analytes. Absolute recovery ranged from 90.1 to 95.4% for sertraline, and from 84.9 to 107.7% for desmethyl-sertraline. The precision was between 0.832-8.552 and 1.730-8.549%, while the accuracy was in the range of -8.467 to 3.385 and -12.067 ην 9.458% for sertraline and desmethyl-sertraline, respectively. A major strength of the method (robustness) to changes in certain chromatographic conditions and parameters of the pretreatment of biological samples has been proven. Furthermore, the stability of the two substances under different storage conditions and the stability of stock solutions and working were studied. The validated method was applied satisfactory on 10 antidepressant drugs with 3 metabolites other than sertraline and desmethyl-sertraline. The method allowed the simultaneous determination of the 15 substances together at subtherapeutic level. The developed method was also successfully applied to qualitative and quantitative analysis of sertraline and desmethyl-sertraline in routine analysis of actual clinical and forensic cases. The proposed method is suitable for determination of sertraline and desmethyl-sertraline in whole blood samples for pharmacokinetic studies, for therapeutic drug level monitoring in order to adjust sertraline dosage of sertraline patients or for the investigation of forensic cases.