Development of a solid phase extraction for 13 'new' generation antidepressants and their active metabolites for gas chromatographic-mass spectrometric analysis

New Method for the Monitoring of Antidepressants in Oral Fluid Using Dried Spot Sampling

The increase in the consumption of antidepressants is a public health problem worldwide, as these are a class of compounds widely used in the treatment of several illnesses, such as depression and anxiety. This work aimed to develop and optimize a method for the quantification of a number of antidepressants and their metabolites (fluoxetine, venlafaxine, O-desmethylvenlafaxine, citalopram, sertraline, and paroxetine) in 100 µL of oral fluid using the dried saliva spots (DSS) sampling approach and gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). The method was validated, presenting linearity within the studied range, with detection and quantification limits ranging between 10 and 100 ng/mL, and coefficients of determination (R²) of at least 0.99 for all analytes. Recoveries were between approximately 13 and 46%. The analysis of precision and accuracy presented acceptable coefficients of variation and relative errors, considering the criteria usually accepted in the validation of bioanalytical procedures. The method herein described is the first to be reported using DSS for the extraction of antidepressants, proving to be a sensitive, simple, and fast alternative to conventional techniques, and capable of being routinely applied in clinical and forensic toxicology scenarios.

Development of a method for assessing the accumulation and metabolization of antidepressant drugs in zebrafish (Danio rerio) eleutheroembryos

Antidepressant drugs are widely used for the treatment of common mental or other psychiatric disorders such as depression, which affect about 121 million people worldwide. This widespread use has contributed to the input of these pharmaceuticals and their metabolites into the environment. The aim of this work was to develop an analytical method to quantify the most widely used antidepressant drugs, selective serotonin reuptake inhibitors (SSRI), and their main metabolites in the environment. For this, a new and reliable miniaturized extraction method based on dispersive SPE cleanup procedure for extraction of SSRI followed by derivatization with n-heptafluorobutyrylimidazole, and detection by GC-MS was developed. The methodology, including a first-order one-compartment model, was then applied to a bioconcentration study in zebrafish (Danio rerio) eleutheroembryos. The results showed low bioaccumulation of these compounds; however, a biotransformation evidence of the parent compounds into their metabolites was observed after 6 h of exposure. These results indicate the need to integrate metabolic transformation rates to fully model and understand the bioaccumulation patterns of SSRI and their metabolites.

Developing and Validating a Fast and Accurate Method to Quantify 18 Antidepressants in Oral Fluid Samples Using SPE and LC-MS-MS

Antidepressant drugs are one of the most widely used medicines for treating major depressive disorders for long time periods. Oral fluid (OF) testing offers an easy and non-invasive sample collection. Detection of antidepressants in OF is important in clinical and forensic settings, such as therapeutic drug monitoring and roadside testing for driving under influence. We developed and validated a comprehensive liquid chromatography-tandem mass spectrometry method for 18 antidepressants (amitriptyline, bupropion, citalopram, clomipramine, cyclobenzaprine, desipramine, desvenlafaxine, doxepin, duloxetine, fluoxetine, imipramine, mirtazapine, nortriptyline, paroxetine, sertraline, trazodone, trimipramine, venlafaxine) in oral fluid collected by Quantisal® oral collection devices. One-half milliliter of Quantisal® OF (125 μL of neat OF) was submitted to solid-phase extraction. The chromatographic separation was performed employing a biphenyl column in gradient mode with a total run time of 5 min. The MS detection was achieved by multiple-reaction monitoring with two transitions per compound. The range for linearity of all analytes was from 10 to 1,000 ng/mL, with a limit of detection of 10 ng/mL. Intra and inter-day accuracy and precision (n = 15) were all within acceptable limits, ±20% error and ±15% relative standard deviation. Analyte recovery at 400 ng/mL concentration (n = 15) ranged from 91 to 129%. Matrix effect ranged from 73.7 to 157%. The internal proficiency test detected all antidepressants with accuracy ranging from 83.1 to 112.1%. The authentic patient sample showed a percentage difference compared to the previously calculated concentration of 86.3-111%. This method provides for the rapid detection of 18 antidepressants and metabolites in OF, which is readily applicable to a routine laboratory.

Simultaneous Quantification of Citalopram and its Main Metabolite, Desmethylcitalopram, in Human Saliva by UHPLC

Background:

This study was designed to develop a reliable method for simultaneous quantita-tion of Citalopram (CIT) and its main active metabolite, Desmethylcitalopram (DCIT), in saliva of patients undergoing treatment with CIT.

Methods:

To compare two procedures of saliva purification, Solid-Phase (SPE) and Liquid-Liquid (LLE) extractions, saliva samples obtained from healthy volunteers were spiked with adequate quantities of CIT and DCIT. Different cartridges were used for SPE, while dichloromethane for LLE. Chromatographic separation and quantitation were carried out by UHPLC with DAD detector using a C-18 column and a mixture of acetonitrile and redistilled water (37:63, v:v) with the addition of formic acid (pH 3.5) as a mobile phase.

Results:

A comparison of both purification procedures showed that the most satisfactory results were obtained by SPE using Discovery C18 cartridge and redistilled water with formic acid (pH 3.5) as a washing solvent. Dichloromethane proved to be the best extractant in LLE. Both procedures enabled the separation of analytes from human saliva with high precision and recovery.

Conclusions:

Validation of the developed UHPLC procedure revealed that, regardless of how the sample was purified, the method was characterized by good linearity (between 10 and 1000 ng/mL), sensitivity, reproducibility, specificity and low values of limits of detection and quantitation. The limits of quantitation were 4.0 and 8.0 ng/mL for SPE and LLE, respectively. The efficiency of the method in therapeutic drug monitoring of CIT and DCIT in saliva of patients was confirmed.

Dispersive liquid-liquid microextraction for the quantification of venlafaxine in environmental waters

The present work describes a new methodology for the detection of the antidepressant venlafaxine (VEN) in aquatic environments using dispersive liquid-liquid microextraction followed by high performance liquid chromatography with fluorescence detection (DLLME-HPLC-FLD). The method developed is fast, low cost, easy to apply, uses a small volume of organic solvents and allows the simultaneous extraction of various samples. The DLLME-HPLC-FLD method presented a linearity range from 25 to 1500 ng L^-1, a detection limit of 24.2 ± 0.2 ng L^-1, and an enrichment factor of 75 ± 4. Recovery tests using solutions of NaCl and humic acids showed that ionic strength and organic matter do not influence the efficiency of the extraction, with extraction recoveries above 77%. Finally, the optimized method was applied to the analysis of water samples from different origins and VEN was only detected in one water sample obtained from a waste water treatment plant (WWTP), which had a concentration of 175 ± 5 ng L^-1. Recovery tests performed in environmental aquatic samples demonstrated that the developed extraction procedure is not influenced by the complex water matrices, with results ranging from 76 to 93%.

Determination of antidepressants in human urine extracted by magnetic multiwalled carbon nanotube poly(styrene-co-divinylbenzene) composites and separation by capillary electrophoresis

Poly(styrene-co-divinylbenzene)-coated magnetic multiwalled carbon nanotube composite synthesized by in-situ high temperature combination and precipitation polymerization of styrene-co-divinylbenzene has been employed as a magnetic sorbent for the solid phase extraction of antidepressants in human urine samples. Fluoxetine, venlafaxine, citalopram and sertraline were, afterwards, separated and determined by capillary electrophoresis with diode array detection. The presence of magnetic multiwalled carbon nanotubes in native poly(styrene-co-divinylbenzene) not only simplified sample treatment but also enhanced the adsorption efficiencies, obtaining extraction recoveries higher than 89.5% for all analytes. Moreover, this composite can be re-used at least ten times without loss of efficiency and limits of detection ranging from 0.014 to 0.041 μg/mL were calculated. Additionally, precision values ranging from 0.08 to 7.50% and from 0.21 to 3.05% were obtained for the responses and for the migration times of the analytes, respectively.

A Novel Liquid-Liquid Extraction for the Determination of Sertraline in Tap Water and Waste Water at Trace Levels by GC-MS

A simple, green and fast analytical method was developed for the determination of sertraline in tap and waste water samples at trace levels by using supportive liquid-liquid extraction with gas chromatography-mass spectrometry. Different parameters affecting extraction efficiency such as types and volumes of extraction and supporter solvents, extraction period, salt type and amount were optimized to get lower detection limits. Ethyl acetate was selected as optimum extraction solvent. In order to improve the precision, anthracene-D10 was used as an internal standard. The calibration plot of sertraline was linear from 1.0 to 1000 ng/mL with a correlation coefficient of 0.999. The limit of detection value under the optimum conditions was found to be 0.43 ng/mL. In real sample measurements, spiking experiments were performed to check the reliability of the method for these matrices. The spiking experiments yielded satisfactory recoveries of 91.19 ± 2.48%, 90.48 ± 5.19% and 95.46 ± 6.56% for 100, 250 and 500 ng/mL sertraline for tap water, and 85.80 ± 2.15% and 92.43 ± 4.02% for 250 and 500 ng/mL sertraline for waste water.

Rapid solid-phase extraction coupled with GC-MS method for the determination of venlafaxine in rat plasma: Application to the drug-drug pharmacokinetic interaction study of venlafaxine combined with fluoxetine

A rapid and sensitive gas chromatography with mass spectrometry method for the determination of venlafaxine in rat plasma has been developed and applied to a drug-drug interaction study of fluoxetine on pharmacokinetics of venlafaxine in rats. Rat plasma was spiked with 2% aqueous ammonia before subjected to preactivated C₁₈ solid-phase extraction columns and eluted with methanol. No endogenous interferences were observed under optimal condition. The calibration curve was linear (R²  = 0.9994) in the range of 10-1000 ng/mL. The quantification limit of venlafaxine in rat plasma was 10 ng/mL. The accuracy was in the range of 85-110%, and the extraction recovery was no less than 50%. Both the intra- and interday precision were 5.0-10.7%. The concentration-time curve showed that plasma concentrations of the coadministration group (group B) were higher than that of single dose group (group A). Both values of C_max (0.069 mg/L) and AUC_0→∞ (0.291 mg h/L) in group B were statistically greater than that of C_max (0.046 mg/L) and AUC_0→∞ (0.181 mg·h/L) in group A (P < 0.05). The results indicated that a significant effect of fluoxetine was shown on the pharmacokinetics of venlafaxine, suggesting that drug-drug interactions are of concern for the treatment of depression with the combined use of venlafaxine and fluoxetine.

Polythiophene-Chitosan Magnetic Nanocomposite as a Highly Efficient Medium for Isolation of Fluoxetine from Aqueous and Biological Samples

Polythiophene/chitosan magnetic nanocomposite as an adsorbent of magnetic solid phase extraction was proposed for the isolation of fluoxetine in aqueous and biological samples prior to fluorescence detection at 246 nm. The synthesized nanoparticles, chitosan and polythiophene magnetic nanocomposite, were characterized by scanning electron microscopy, FT-IR, TGA, and EDAX. The separation of the target analyte from the aqueous solution containing the fluoxetine and polythiophene/chitosan magnetic nanocomposite was simply achieved by applying external magnetic field. The main factors affecting the extraction efficiency including desorption conditions, extraction time, ionic strength, and sample solution pH were optimized. The optimum extraction conditions were obtained as 10 min for extraction time, 25 mg for sorbent amount, 50 mL for initial sample volume, methanol as desorption solvent, 1.5 mL for desorption solvent volume, 3 min for desorption time, and being without salt addition. Under the optimum conditions, good linearity was obtained within the range of 15-1000 μg L(-1) for fluoxetine, with correlation coefficients 0.9994. Furthermore, the method was successfully applied to the determination of fluoxetine in urine and human blood plasma samples. Compared with other methods, the current method is characterized with highly easy, fast separation and low detection limits.

QbD-Driven Development and Validation of a Bioanalytical LC-MS Method for Quantification of Fluoxetine in Human Plasma

The current studies describe the Quality by Design (QbD)-based development and validation of a LC-MS-MS method for quantification of fluoxetine in human plasma using fluoxetine-D5 as an internal standard (IS). Solid-phase extraction was employed for sample preparation, and linearity was observed for drug concentrations ranging between 2 and 30 ng/mL. Systematic optimization of the method was carried out by employing Box-Behnken design with mobile phase flow rate (X1), pH (X2) and mobile phase composition (X3) as the method variables, followed by evaluating retention time (Rt) (Y1) and peak area (Y2) as the responses. The optimization studies revealed reduction in the variability associated with the method variables for improving the method robustness. Validation studies of the developed method revealed good linearity, accuracy, precision, selectivity and sensitivity of fluoxetine in human plasma. Stability studies performed in human plasma through freeze-thaw, bench-top, short-term and long-term cycles, and autosampler stability revealed lack of any change in the percent recovery of the drug. In a nutshell, the developed method demonstrated satisfactory results for analysis of fluoxetine in human plasma with plausible utility in pharmacokinetic and bioequivalence studies.

Determination of selective serotonin reuptake inhibitors in biological samples via magnetic stirring-assisted dispersive liquid–liquid microextraction followed by high performance liquid chromatography

This work reports an efficient, quick and low-cost procedure for the determination of serotonin reuptake inhibitors (SSRIs) in low concentration levels in biological fluids.

Quantification of 33 antidepressants by LC-MS/MS--comparative validation in whole blood, plasma, and serum

In the present study, a liquid chromatography-mass spectrometry (LC-MS/MS) multi-analyte approach based on a simple liquid-liquid extraction was developed for fast target screening and quantification of 33 antidepressants in whole blood, plasma, and serum. The method was validated with respect to selectivity, matrix effects, recovery, process efficiency, accuracy and precision, stabilities, and limits. In addition, cross-calibration between the three biosamples was done to assess the impact of the different matrices on the calibration. Whole blood, plasma, and serum (500 μL each) were extracted twice at pH 7.4 and at pH 10 with ether-ethyl acetate (1:1). Separation, detection, and quantification were performed using LC-MS/MS with electrospray ionization in positive mode. For accuracy and precision, full calibration was performed with ranges from subtherapeutic to toxic concentrations. The approach was sensitive and selective for 33 analytes in whole blood and 31 analytes in plasma and serum and accurate and precise for 30 of the 33 tested drugs in whole blood, 31 in plasma, and 28 in serum. Cross-calibration was successful only for 13 analytes in whole blood and 16 analytes in serum calculated over a calibration curve made in plasma, 12 analytes in whole blood and 15 analytes in plasma calculated over a calibration curve made in serum, and 10 analytes in plasma and 15 analytes in serum calculated over a calibration curve made in whole blood.

Exposures to a selective serotonin reuptake inhibitor (SSRI), sertraline hydrochloride, over multiple generations: changes in life history traits in Ceriodaphnia dubia

Selective serotonin reuptake inhibitors (SSRIs) have been reported to range from low parts per trillion to parts per billion levels in surface waters, wastewater effluents, and sediments. These low levels have led to concern for their potential long-term risks to the survival, growth, and reproduction of aquatic organisms. We investigated the acute and chronic effects of sertraline on the life history traits of Ceriodaphnia dubia over the course of three generations under environmentally realistic concentrations. Acute toxicity of sertraline in C. dubia offspring resulted in a 48h median effective concentration of 126µgL(-1). Under chronic exposure, the lowest concentration to affect fecundity and growth was at 53.4µgL(-1) in the first two generations. These parameters become more sensitive during the third generation where the LOEC was 4.8µgL(-1). The median effective concentrations (EC50) for the number of offspring per female, offspring body size, and dry weight were 17.2, 21.2, and 26.2µgL(-1), respectively. Endpoints measured in this study demonstrate that chronic exposure of C. dubia to sertraline leads to effects that occur at concentrations only an order of magnitude higher than predicted environmental concentrations. However, this study also demonstrates that multigenerational effects should be considered in chronic exposure studies because standard toxicity tests do not account for increases in sensitivity in successive generations to toxicants.

Determination of paroxetine in blood and urine using micellar liquid chromatography with electrochemical detection

Paroxetine is a potent selective serotonin reuptake inhibitor used for the treatment of depression and related mood disorders. A micellar liquid chromatographic method was developed for the determination of paroxetine in serum and urine. Detection of paroxetine was carried out using a C18 column and a mobile phase of 0.15 M sodium dodecyl sulfate, 6% 1-pentanol at pH 3 (buffer salt 0.01 M NaH2PO4) running under isocratic mode at 1.0 mL/min and electrochemical detection at 0.8 V. The analyte was eluted without interferences in <15 min. The proposed methodology was validated under the guidelines of the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use in matrix in terms of specificity, linearity (r(2) > 0.9999; 0.5-5 μg/mL range), accuracy (88-97.5%, recovery), repeatability (RSD < 0.54%), intermediate precision (RSD < 0.54%), limit of detection and quantification (0.001 and 0.005 μg/mL, respectively) and robustness (RSD < 3.63%). Developed method was successfully applied to real blood and urine samples as well as in spiked serum and urine samples. The developed method was specific, rapid, precise, reliable, accurate, inexpensive and then suitable for routine analysis of paroxetine in monitorized samples.

Simultaneous Screening of 177 Drugs of Abuse in Urine Using Ultra-performance Liquid Chromatography with Tandem Mass Spectrometry in Drug-intoxicated Patients

Objective

The demand for rapid and broad clinical toxicology screening methods to identify drugs of abuse and medicinal drugs is increasing steadily. Liquid chromatography-tandem mass spectrometry (LC-TMS) is increasingly used to screen for drugs of abuse and to identify a wide range of drugs and metabolites in clinical samples. We revised a high-throughput and rapid ultra-performance (UP) LC-TMS method for simultaneous screening of 177 of the most prevalent medicinal drugs and drugs of abuse in urine and validated the quality of performance using system suitability mixture (SSM) and quality control (QC) materials.

Methods

We assessed the limits of detection (LOD) using high concentrations of the test substances. The method was applied to 473 urine samples obtained from patients intoxicated with drugs who visited the emergency center.

Results

The retention time, peak area, and total ion chromatogram of the SSM and QC materials were within the acceptance criteria of the pre-defined acceptance interval. The LODs were <62 ng/ml for 12 commonly encountered drugs. In total, 418 patients (88.4%) tested positive for one or more medicinal drugs or drugs of abuse. Twenty-eight drugs were detected over ten times; the most commonly detected were zolpidem, ephedrine, paracetamol, and chlorpheniramine.

Conclusion

The UPLC-TMS method provided excellent performance for simultaneous screening of a large number of the drugs of abuse in urine samples. We conclude that this robust technique is useful for screening for a large number of drugs and for rapid screening of the most commonly encountered substances in emergency cases.

Magnetic solid phase extraction of mefenamic acid from biological samples based on the formation of mixed hemimicelle aggregates on Fe(3)O(4) nanoparticles prior to its HPLC-UV detection

A novel and sensitive solid phase extraction method based on the adsorption of cetyltrimethylammonium bromide on the surface of Fe3O4 nanoparticles was developed for extraction and preconcentration of ultra-trace amounts of mefenamic acid in biological fluids. The remarkable properties of Fe3O4 nanoparticles including high surface area and strong magnetization were utilized in this SPE procedure so that a high enrichment factor (98) and satisfactory extraction recoveries (92-99%) were obtained using only 50mg of magnetic adsorbent. Furthermore, a fast separation time (about 15min) was achieved for a large sample volume (200mL) avoiding time-consuming column-passing process of conventional SPE. A comprehensive study on the parameters effecting the extraction recovery such of the amount of surfactant, pH value, the amount of Fe3O4 nanoparticles, sample volume, desorption conditions and ionic strength were also presented. Under the optimum conditions, the method was linear in the 0.2-200ngmL(-1) range and good linearity (r(2)>0.9991) was obtained for all calibration curves. The limit of detection was 0.097 and 0.087ngmL(-1) in plasma and urine samples, respectively. The relative standard deviation (RSD %) for 10 and 50ngmL(-1) of the analyte (n=5) were 1.6% and 2.1% in plasma and 1.2% and 1.9% in urine samples, respectively. Finally, the method was successfully applied to the extraction and preconcentration of mefenamic acid in human plasma and urine samples.

Active metabolites as antidepressant drugs: the role of norquetiapine in the mechanism of action of quetiapine in the treatment of mood disorders

Active metabolites of some antipsychotic drugs exhibit pharmacodynamic and pharmacokinetic properties that may be similar to or differ from the original compound and that can be translated by a different profile of responses and interactions to clinical level. Some of these antipsychotics' active metabolites might participate in mechanisms of antidepressant activity, as m-chlorophenylpiperazine (aripiprazole), 9-OH-risperidone and norquetiapine. Norquetiapine exhibits distinct pharmacological activity from quetiapine and plays a fundamental role in its antidepressant efficacy. In this review, we analyze the differential pharmacological aspects between quetiapine and norquetiapine, both from the pharmacokinetic and pharmacodynamic perspectives (affinity for dopaminergic, noradrenegic, and/or serotonergic receptors, etc.), as well as differential neuroprotective role. The pharmacological differences between the two drugs could explain the differential clinical effect, as well as some differences in tolerability profile and drug interactions. The available data are sufficient to arrive at the conclusion that antidepressant activity of quetiapine is mediated, at least in part, by the active metabolite norquetiapine, which selectively inhibits noradrenaline reuptake, is a partial 5-HT1A receptor agonist, and acts as an antagonist at presynaptic α2, 5-HT2C, and 5-HT7 receptors.

A fast, sensitive and simple method for mirtazapine quantification in human plasma by HPLC-ESI-MS/MS. Application to a comparative bioavailability study

In the present study a simple, fast, sensitive and robust method to quantify mirtazapine in human plasma using quetiapine as the internal standard (IS) is described. The analyte and the IS were extracted from human plasma by a simple protein precipitation with methanol and were analyzed by high-performance liquid chromatography coupled to an electrospray tandem triple quadrupole mass spectrometer (HPLC-ESI-MS/MS). Chromatography was performed isocratically on a C(18), 5 µm analytical column and the run time was 1.8 min. The lower limit of quantitation was 0.5 ng/mL and a linear calibration curve over the range 0.5-150 ng/mL was obtained, showing acceptable accuracy and precision. This analytical method was applied in a relative bioavailability study in order to compare a test mirtazapine 30 mg single-dose formulation vs a reference formulation in 31 volunteers of both sexes. The study was conducted in an open randomized two-period crossover design and with a 14 day washout period. Since the 90% confidence interval for C(max) , AUC(last) and AUC(0-inf) were within the 80-125% interval proposed by the Food and Drug Administration and ANVISA (Brazilian Health Surveillance Agency), it was concluded that mirtazapine 30 mg/dose is bioequivalent to the reference formulation, according to both the rate and extent of absorption.

A fully validated method for the simultaneous determination of 11 antidepressant drugs in whole blood by gas chromatography-mass spectrometry

Antidepressant drugs are widely used for the treatment of depression and other psychiatric disorders and as a result they are involved in numerous clinical and forensic cases. The aim of this study was the development, optimization and validation of a simple, specific and sensitive GC/MS method for the simultaneous determination of 11 antidepressant drugs and 4 of their metabolites (amitriptyline, citalopram, clomipramine, fluoxetine, fluvoxamine, maprotiline, desmethyl-maprotiline, mirtazapine, desmethyl-mirtazapine, nortriptyline, paroxetine, sertraline, desmethyl-sertraline, venlafaxine and desmethyl-venlafaxine) in whole blood. The combination of solid-phase extraction with derivatization using heptafluorobutyric anhydride efficiently reduced matrix effect and improved sensitivity of the method. In this assay, protriptyline was used as internal standard. Absolute recovery values for all analytes were ranged from 79.2 to 102.6%. LODs and LOQs were found to be between 0.30-1.50 μg/L and 1.00-5.00 μg/L, respectively. The calibration curves were linear (R(2)≥0.990) within the range of 5.00-1000 μg/L for all analytes. Accuracy expressed as the % E(r) was found to be between -12.3 and 12.2%. Precision expressed as the % RSD was found to be less than 11.7% for all antidepressants. The developed method proved to be suitable for routine work and it was used to successfully analyze more than 2500 clinical and forensic blood samples.