Comparison of electron and chemical ionization modes by validation of a quantitative gas chromatographic-mass spectrometric assay of new generation antidepressants and their active metabolites in plasma

Development of fluorescence probe for spectrofluorimetric determination of viloxazine hydrochloride in pharmaceutical form and rat plasma; additional pharmacokinetic study

Attention deficit hyperactivity disorder (ADHD) is a neurological condition frequently identified in early childhood and frequently co-occurs with other neuropsychological disorders, particularly autism. Viloxazine hydrochloride, a non-stimulant medication, has recently gained approval for treating attention-deficit hyperactivity disorder. This paper describes the first spectrofluorimetric method for precisely measuring the content of viloxazine in pharmaceutical capsules and rat plasma. This method employed NBD-Cl (4-chloro-7-nitrobenzo-2-oxa-1,3-diazole) as a fluorescent probe, which transformed viloxazine in an alkaline environment into a remarkably sensitive fluorescent adduct. Upon excitation at 476 nm, this adduct becomes detectable at a wavelength of 536 nm. The method was validated using ICH criteria, revealing acceptable linearity across a concentration range of 200-2000 ng/ml and high sensitivity with LOD and LOQ values of 46.774 ng/ml and 141.741 ng/ml, respectively. This method was adeptly applied in a pharmacokinetic study of viloxazine in rat plasma following a single oral dose (10 mg/kg), yielding a mean peak plasma concentration (Cmax) of 1721 ng/ml, achieved within 1.5 h. Furthermore, the environmental impact of the technique was assessed using two greenness assessment tools, revealing a notable level of eco-friendliness and sustainability.

Development of a Novel Analytical Method for Determining Trazodone in Human Plasma by Liquid Chromatography Coupled With Mass Spectrometry Coupled With Automatic 2-Dimensional Liquid Chromatograph-Mass Spectrometer Coupler 9500 and Its Application to Therapeutic Drug Monitoring

BACKGROUND

Trazodone (TZD) is a tetracyclic serotonin antagonist and reuptake inhibitor that is used as a second-generation phenylpiperazine antidepressant. However, the plasma concentrations of TZD have shown individual variations in clinical practice. Quantification of TZD plasma concentrations may be an effective and valuable method to balance the clinical efficacy and adverse reactions. This study aimed to establish a novel liquid chromatography coupled with mass spectrometry (LC-MS) assay for measuring TZD concentrations in human plasma for therapeutic drug monitoring (TDM).

METHODS

After protein precipitation with acetonitrile, LC-MS quantification of TZD was performed in the multiple reaction monitoring mode with chromatographic separation using a mobile phase of MeOH and 0.1% formic acid in water. This method validation intends to investigate specificity, sensitivity, linearity, precision, accuracy, recovery, matrix effect, and stability according to United states food and drug administration guidelines.

RESULTS

This method showed good selectivity because no interfering peaks were observed in the plasma samples during the 2-minute run time. The range of the calibration curve was 1-3000 ng/mL. The detection and quantification limits were 0.3 and 1 ng/mL, respectively. The intraday and interday accuracies were 96.5%-103.4%, with precision relative SD% values of <5%, except for the limit of quality. The mean TZD recovery from human plasma was 95.4%-104.5%. Finally, this method was successfully applied to TDM in 20 patients. The TZD plasma concentrations of the patients ranged between 21.5 and 2267.3 ng/mL.

CONCLUSIONS

A novel analytical method was established to measure TZD by LC-MS coupled with an automatic 2-dimensional liquid chromatograph mass spectrometer coupler 9500 (LC-MS/MS-Mate 9500), which is superior to the ordinary LC-MS system in separation, transport, anti-interference, sensitivity, and quantitative analysis stability.

Resonance Rayleigh scattering approach based on association complex formation with erythrosine B for determination of venlafaxine, Application to the dosage form and spiked human plasma

The interaction of Venlafaxine Hydrochloride (VLX) with Erythrosine B was investigated by resonance Rayleigh scattering (RRS) spectroscopic technique. In acetate buffer (pH 3.4), erythrosine B reacted with VLX to form 1:1 ion pair complex with concomitant enhancement in RRS intensity which was measured at 330 nm. In addition, the stability constant and the change in free energy of the reaction were estimated. Based on this interaction a new method was developed for the sensitive VLX analysis using Erythrosine B as a probe. The results indicated that this method had a good selectivity in the presence of coexisting compounds. The scattering intensity (ΔI_RRS ) was linearly depended on VLX concentration over the range of 0.04-1.0 μg mL^-1 with determination coefficient (r) of 0.9998. The detection (LOD) and quantitation limits (LOQ) were 0.01 and 0.03 μg mL^-1 , respectively. This method could be suitably employed to the VLX analysis in pharmaceutical capsules and human plasma.

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.

Application of Bar Adsorptive Microextraction for the Determination of Levels of Tricyclic Antidepressants in Urine Samples

This work entailed the development, optimization, validation, and application of a novel analytical approach, using the bar adsorptive microextraction technique (BAμE), for the determination of the six most common tricyclic antidepressants (TCAs; amitriptyline, mianserin, trimipramine, imipramine, mirtazapine and dosulepin) in urine matrices. To achieve this goal, we employed, for the first time, new generation microextraction devices coated with convenient sorbent phases, polymers and novel activated carbons prepared from biomaterial waste, in combination with large-volume-injection gas chromatography-mass spectrometry operating in selected-ion monitoring mode (LVI-GC-MS(SIM)). Preliminary assays on sorbent coatings, showed that the polymeric phases present a much more effective performance, as the tested biosorbents exhibited low efficiency for application in microextraction techniques. By using BAμE coated with C18 polymer, under optimized experimental conditions, the detection limits achieved for the six TCAs ranged from 0.2 to 1.6 μg L-1 and, weighted linear regressions resulted in remarkable linearity (r2 > 0.9960) between 10.0 and 1000.0 μg L-1. The developed analytical methodology (BAμE(C18)/LVI-GC-MS(SIM)) provided suitable matrix effects (90.2-112.9%, RSD ≤ 13.9%), high recovery yields (92.3-111.5%, RSD ≤ 12.3%) and a remarkable overall process efficiency (ranging from 84.9% to 124.3%, RSD ≤ 13.9%). The developed and validated methodology was successfully applied for screening the six TCAs in real urine matrices. The proposed analytical methodology proved to be an eco-user-friendly approach to monitor trace levels of TCAs in complex urine matrices and an outstanding analytical alternative in comparison with other microextraction-based techniques.

Edge plane pyrolytic graphite as a sensing surface for the determination of fluvoxamine in urine samples of obsessive-compulsive disorder patients

There is an increasing demand for fast and sensitive determination of antidepressants in human body fluids because of the present scenario of rising depression cases at the global level. A simple and sensitive voltammetric method using edge plane pyrolytic graphite electrode (EPPGE) as a novel sensor is presented for the determination of antidepressant fluvoxamine in urine and blood plasma samples of obsessive-compulsive disorder (OCD) patients. EPPGE is delineated the first time for this determination. EPPGE exhibited strong electrocatalytic activity and enhanced reduction signal towards the sensing of fluvoxamine. Fluvoxamine gave a well-defined reduction peak at ~ - 670 mV using EPPGE. The fluvoxamine reduction peak current was linear to its concentration in the range 5.00 × 10^-9 - 0.1 × 10^-6 mol L^-1 and the limit of detection was found to be 3.5 × 10^-9 mol L^-1. The pre-eminence of EPPGE over mercury electrodes has been proved in terms of sensitivity and imperative analytical parameters. The pH study reveals the involvement of an equal number of electrons and protons in the reduction reaction mechanism. The frequency study indicated the adsorption controlled irreversible reaction mechanism. The stability and reproducibility of the offered sensor were also found most favorable. The interference study confirmed the optimum selectivity of the proposed sensor. The edge plane pyrolytic graphite sensing platform is recommended as a potential contender for the accurate and fast determination of fluvoxamine in depression medications as well as biological specimens of OCD patients.

Cost-Effective Potentiometric Platforms Modified with Multi-Walled Carbon Nanotubes (MWCNTs) and Based on Imprinted Receptors for Fluvoxamine Assessment

A simple, efficient and reliable analytical method was developed and used for the determination of the fluvoxamine drug (FLV) in pharmaceutical preparations and biological fluids. The method is based on the cost-effective screen-printed platform for the potential transduction of the drug. Host-tailored molecular imprinting polymer (MIP) was integrated with the potentiometric platform as a recognition receptor, in which FLV, acrylamide (AAm), ethylene glycol dimethacrylate (EGDMA) and acetonitrile were used as a template, functional monomer, cross-linker, and solvent, respectively. MIP particles were dispersed in plasticized poly (vinyl chloride) (PVC) and the membrane was drop-casted on carbon screen-printed electrode. The MIP, in addition to non-imprinted polymers (NIP), was characterized and the binding experiment revealed high affinity and adsorption capacity of MIP towards FLV. The proposed sensor displayed near-Nernstian cationic slope of 55.0 ± 0.8 mV/decade (r² = 0.999) with a low detection limit of 4.8 × 10⁻⁶ mol/L over a wide pH range (3.0–8.5). The electrochemical features of the proposed sensors including electrochemical impedance spectroscopy (EIS) and chronopotentiometry measurements (CP) in the presence of multi-walled carbon nanotubes (MWCNTs) as a solid contact transducer were also investigated. The applications of the proposed sensor for the determination of FLV in different dosage forms with recovery values (98.8%–101.9%) and (97.4%–101.1%), respectively compared with the reference HPLC method with acceptedFandt-student tests values at the 95% confidence level.

Spectroscopic methods to analyze drug metabolites

Drug metabolites have been monitored with various types of newly developed techniques and/or combination of common analytical methods, which could provide a great deal of information on metabolite profiling. Because it is not easy to analyze whole drug metabolites qualitatively and quantitatively, a single solution of analytical techniques is combined in a multilateral manner to cover the widest range of drug metabolites. Mass-based spectroscopic analysis of drug metabolites has been expanded with the help of other parameter-based methods. The current development of metabolism studies through contemporary pharmaceutical research are reviewed with an overview on conventionally used spectroscopic methods. Several technical approaches for conducting drug metabolic profiling through spectroscopic methods are discussed in depth.

Current state of bioanalytical chromatography in clinical analysis

Chromatographic methods have become popular in clinical analysis in both routine and research laboratories.

Preparation of a magnetic molecularly imprinted polymer for the selective adsorption of chlordiazepoxide and its determination by central composite design optimized HPLC

Core–shell magnetic molecularly imprinted polymer nanoparticles (MMIP-NPs) were prepared and applied in the extraction of chlordiazepoxide from various samples.

Toxicokinetics, disposition and metabolism of fluoxetine in crabs

The disposition and metabolism of fluoxetine in the European shore crab and the Dungeness crab were assessed. Crabs received intracardiac doses of either 0.13 μg/kg or 0.5 mg/kg fluoxetine, respectively. In addition, fluoxetine was administered to Metacarcinus cancer by oral gavage at 7.8 mg/kg. The distribution of fluoxetine was quantified in haemolymph and digestive gland for both crabs, as well as brain, muscle, and testis of Carcinus maenas, over 12 days. The metabolite norfluoxetine, was also measured in C. maenas. Fluoxetine was mainly found in lipid rich tissues. Distribution coefficients increased for digestive gland until three days after fluoxetine administration and then decreased until the end of the observations. The highest distribution coefficients were obtained for brain. Norfluoxetine displayed continuously high levels in digestive gland and brain. The strong decrease in fluoxetine and the concomitant increase in norfluoxetine demonstrates that decapod crustaceans metabolise fluoxetine into the more biologically active norfluoxetine. Fluoxetine levels in the haemolymph of M. cancer declined within 20 h, but showed a second peak 25 h later, suggesting remobilisation from tissues sequestering the compound. The steady state volume distribution and the total body clearance of fluoxetine were high, consistent with high diffusion of fluoxetine into the peripheral tissues and biotransformation as an important elimination pathway. Oral administration of fluoxetine prolonged its half-life in M. cancer, but bioavailability was low. These results confirm the high distribution into nervous tissue, extensive biotransformation into the highly active norfluoxetine and a half-life similar to that observed in vertebrates.

Determination of fluvoxamine maleate in human urine and human serum using alkaline KMnO4 -rhodamine B chemiluminescence

The flow-injection chemiluminescence (FI-CL) behavior of a gold nanocluster (Au NC)-enhanced rhodamine B-KMnO₄ system was studied under alkaline conditions for the first time. In the present study, the as-prepared bovine serum albumin-stabilized Au NCs showed excellent stability and reproducibility. The addition of trace levels of fluvoxamine maleate (Flu) led to an obvious decline in CL intensity in the rhodamine B-KMnO₄ -Au NCs system, which could be used for quantitative detection of Flu. Under optimized conditions, the proposed CL system exhibited a favorable analytical performance for Flu determination in the range 2 to 100 μg ml^-1 . The detection limit for Flu measurement was 0.021 μg ml^-1 . Moreover, this newly developed system revealed outstanding selectivity for Flu detection when compared with a multitude of other species, such as the usual ions, uric acid and a section of hydroxy compounds. Additionally, CL spectra, UV-visible spectroscopes and fluorescence spectra were measured in order to determine the possible reaction mechanism. This approach could be used to detect Flu in human urine and human serum samples with the desired recoveries and could have promising application under physiological conditions.

Determination of clozapine, and five antidepressants in human plasma, serum and whole blood by gas chromatography-mass spectrometry: A simple tool for clinical and postmortem toxicological analysis

In this study, we describe a simple and rapid method for the determination of the antipsychotic drug clozapine and five commonly co-administered antidepressants - bupropion, mirtazapine, sertraline, clomipramine and citalopram - in serum, plasma and whole blood. Sample preparation includes solid phase extraction of analytes and determination of drug concentrations by gas chromatography-mass spectrometry without any derivatization steps. The method was fully validated according to international criteria and can be successfully applied for routine analyses. Correlation coefficients of calibration curves for the tested drugs in the three specimens were in the range 0.9977-0.9999. Intra-day and inter-day precisions ranged from 0.81-7.85% and 3.60-12.91% respectively for the studied analytes and matrices. Recoveries were satisfactory for different concentrations of each drug in each specimen allowing accurate determinations in the range from sub-therapeutic to toxic levels. The presented method shows acceptable sensitivity, linearity in wide concentration ranges (sub-therapeutic, therapeutic, supra-therapeutic/toxic levels), it is simple and rapid and it is applicable for qualitative and quantitative routine toxicological analyses of clinical and postmortem cases.

Wastewater treatment plant effluent alters pituitary gland gonadotropin mRNA levels in juvenile coho salmon (Oncorhynchus kisutch)

It is well known that endocrine disrupting compounds (EDCs) present in wastewater treatment plant (WWTP) effluents interfere with reproduction in fish, including altered gonad development and induction of vitellogenin (Vtg), a female-specific egg yolk protein precursor produced in the liver. As a result, studies have focused on the effects of EDC exposure on the gonad and liver. However, impacts of environmental EDC exposure at higher levels of the hypothalamic-pituitary-gonad axis are less well understood. The pituitary gonadotropins, follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh) are involved in all aspects of gonad development and are subject to feedback from gonadal steroids making them a likely target of endocrine disruption. In this study, the effects of WWTP effluent exposure on pituitary gonadotropin mRNA expression were investigated to assess the utility of Lh beta-subunit (lhb) as a biomarker of estrogen exposure in juvenile coho salmon (Oncorhynchus kisutch). First, a controlled 72-h exposure to 17α-ethynylestradiol (EE2) and 17β-trenbolone (TREN) was performed to evaluate the response of juvenile coho salmon to EDC exposure. Second, juvenile coho salmon were exposed to 0, 20 or 100% effluent from eight WWTPs from the Puget Sound, WA region for 72h. Juvenile coho salmon exposed to 2 and 10ng EE2L(-1) had 17-fold and 215-fold higher lhb mRNA levels relative to control fish. Hepatic vtg mRNA levels were dramatically increased 6670-fold, but only in response to 10ng EE2L(-1) and Fsh beta-subunit (fshb) mRNA levels were not altered by any of the treatments. In the WWTP effluent exposures, lhb mRNA levels were significantly elevated in fish exposed to five of the WWTP effluents. In contrast, transcript levels of vtg were not affected by any of the WWTP effluent exposures. Mean levels of natural and synthetic estrogens in fish bile were consistent with pituitary lhb expression, suggesting that the observed lhb induction may be due to estrogenic activity of the WWTP effluents. These results suggest that lhb gene expression may be a sensitive index of acute exposure to estrogenic chemicals in juvenile coho salmon. Further work is needed to determine the kinetics and specificity of lhb induction to evaluate its utility as a potential indicator of estrogen exposure in immature fish.

The pharmacokinetics of mianserin suppositories for rectal administration in dogs and healthy volunteers: a pilot study

BACKGROUND

We formulated mianserin suppositories for the treatment of delirium and evaluated their pharmacokinetics by measuring plasma drug concentrations in dogs and healthy human volunteers.

METHODS

Mianserin suppositories were prepared by a melting technique using Tetramide® tablets and Witepsol H-15 as the suppository base. Pharmacokinetics of this 30-mg mianserin preparation were evaluated in three beagle dogs and three healthy adult males, in line with ethics committee approval. Plasma mianserin levels were determined using gas chromatography-mass spectrometry.

RESULTS

In dogs, the maximum plasma mianserin concentration (Cmax) was 1.3 ± 0.4 ng/mL, the time to Cmax (tmax) was 5.5 ± 4.3 h, and the area under the plasma concentration-time curve from 0 to 24 h (AUC0-24) was 18.9 ± 1.9 h・ng/mL. In humans, the Cmax was 14.6 ± 6.3 ng/mL, the tmax was 8 h, and the AUC0-24 was 266 ± 103 h・ng/mL.

CONCLUSIONS

The current study characterized the pharmacokinetics of mianserin suppositories in dogs and humans. As compared to oral administration, the suppositories produced a lower Cmax and a delayed tmax, although AUC0-24 values were comparable. It will be necessary to identify an appropriate dose that produces an adequate plasma mianserin concentration for effective and safe clinical use.

TRIAL REGISTRATION

UMIN000013853.

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.

High performance liquid chromatographic determination of ultra traces of two tricyclic antidepressant drugs imipramine and trimipramine in urine samples after their dispersive liquid-liquid microextraction coupled with response surface optimization

Dispersive liquid-liquid microextraction (DLLME) coupled with high performance liquid chromatography by ultraviolet detection (HPLC-UV) as a fast and inexpensive technique was applied to the determination of imipramine and trimipramine in urine samples. Response surface methodology (RSM) was used for multivariate optimization of the effects of seven different parameters influencing the extraction efficiency of the proposed method. Under optimized experimental conditions, the enrichment factors and extraction recoveries were between 161.7-186.7 and 97-112%, respectively. The linear range and limit of detection for both analytes found to be 5-100ng mL(-1) and 0.6ng mL(-1), respectively. The relative standard deviations for 5ng mL(-1) of the drugs in urine samples were in the range of 5.1-6.1 (n=5). The developed method was successfully applied to real urine sample analyses.

The development and validation of a turbulent flow-liquid chromatography-tandem mass spectrometric method for the simultaneous quantification of citalopram, sertraline, bupropion and hydroxybupropion in serum

OBJECTIVES

Depression is a rapidly growing issue in the United States. There are many drug classes that may be used to treat depression, including the selective serotonin-reuptake inhibitors (SSRIs) citalopram (Celexa®) and sertraline (Zoloft®), as well as the aminoketone bupropion (Wellbutrin®). However, therapeutic efficacy and treatment success is often variable, requiring changes in dosing regimens or drug selection. Methods for drug quantification can become important tools in the assessment of drug efficacy to optimize treatment regimens. Here, we present a turbulent flow-liquid chromatography-tandem mass spectrometric (TFC-MS/MS) method for the robust, simultaneous quantification of citalopram, sertraline, bupropion and its active metabolite, hydroxybupropion (OH-bupropion).

DESIGN AND METHODS

Serum spiked with the aforementioned antidepressants, along with their corresponding isotopically labeled internal standards was subjected to protein precipitation. Samples were injected onto a TFC column for on-line solid phase extraction and a Hypersil Gold C18 column for chromatographic separation. Detection was achieved using a TSQ Vantage mass spectrometer. Assay validation followed FDA bioanalytical guidelines.

RESULTS

The analytical measuring range for all analytes spanned from 5 to 1000ng/mL. Intra- and inter-assay precision across four quality control levels were ≤9.2% and ≤14.8%, respectively. A comparison to other LC-MS/MS methods resulted in a strong correlation with correlation coefficients ranging from 0.9929 to 0.9971. Carryover, stability, recovery, matrix effects, extraction and processing efficiency were also deemed acceptable in accordance with FDA recommendations.

CONCLUSIONS

The development and validation of this TFC-MS/MS method allow for the robust and high-throughput quantification of commonly prescribed antidepressants.

Potassium permanganate-acridine yellow chemiluminescence system for the determination of fluvoxamine, isoniazid and ceftriaxone

Based on the oxidation of acridine yellow by permanganate in basic medium, a new chemiluminescence system was developed for the sensitive determination of some important drugs. The remarkable inhibiting effect of fluvoxamine, ceftriaxone and isoniazid on this reaction was applied to their detection. A possible mechanism was proposed for this system based on chemiluminescence emission wavelengths and experimental observations. Under optimum conditions, calibration graphs were obtained for 1 × 10(-9) to 1 × 10(-6) mol/L of fluvoxamine; 2 × 10(-8) to 8 × 10(-6) mol/L of ceftriaxone and 5 × 10(-8) to 4 × 10(-5) mol/L of isoniazid. This proposed method was satisfactorily used in the determination of these drugs in pharmaceutical samples and human urine and serum.

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.

Spectrofluorimetric determination of sertraline in dosage forms and human plasma through derivatization with 9-fluorenylmethyl chloroformate

BACKGROUND

Sertraline is primarily used to treat major depression in adult outpatients as well as obsessive-compulsive, panic and social anxiety disorders in both adults and children. A survey of the literature reveals that most of the reported methods are either insufficiently sensitive or tedious and require highly sophisticated and dedicated instrumentation. The proposed method is considered to be specific for determination of SER in presence of its metabolite (deaminated form).

RESULTS

A sensitive, simple and specific spectrofluorimetric method was developed for the determination of sertraline (SER) in pharmaceutical formulations and biological fluids. The method is based on its reaction with 9-fluorenylmethyl chloroformate (FMOC-Cl) in borate buffer of pH 8.0 to yield a highly fluorescent derivative peaking at 315 nm after excitation at 265 nm. The different experimental parameters affecting the development and stability of the reaction product were carefully studied and optimized. The fluorescence concentration plot was rectilinear over the range of 0.05-1.0 μg mL-1 with a lower detection limit of 5.34 × 10-3 μg mL-1 and limit of quantitation of 0.016 μg mL-1.

CONCLUSIONS

The proposed method was successfully applied to the analysis of commercial tablets and the results obtained were in good agreement with those obtained using the reference method. Furthermore, the method was applied for the determination of SER in spiked and real human plasma. The mean % recovery (n = 3) was 94.33 ± 1.53 and 92.00 ± 2.65, respectively. A proposal of the reaction pathway was postulated.