Modification of the association between paroxetine serum concentration and SERT-occupancy by ABCB1 (P-glycoprotein) polymorphisms in major depressive disorder.

BACKGROUND: Selective serotonin reuptake inhibitors (SSRIs) exert substantial variability in effectiveness in patients with major depressive disorder (MDD), with up to 50-60% not achieving adequate response. Elucidating pharmacokinetic factors that explain this variability is important to increase treatment effectiveness. OBJECTIVES: To examine potential modification of the relationship between paroxetine serum concentration (PSC) and serotonin transporter (SERT)-occupancy by single nucleotide polymorphisms (SNPs) of the ABCB1 gene, coding for the P-glycoprotein (P-gp) pump, in MDD patients. To investigate the relationship between ABCB1 SNPs and clinical response. METHODS: Patients had MDD and received paroxetine 20 mg/day. We measured PSC after 6 weeks. We quantified SERT-occupancy with SPECT imaging (n = 38) and measured 17-item Hamilton Depression Rating Scale (HDRS17)-scores at baseline and after 6 weeks (n = 81). We genotyped ABCB1 at rs1045642 [3435C>T], rs1128503 [1236C>T], rs2032582 [2677G>T/A] and rs2235040 [2505G>A]. For our primary aim, we modeled mean SERT-occupancy in an Emax nonlinear regression model with PSC and assessed whether the model improved by genetic subgrouping. For our secondary aim, we used multivariate linear regression analysis. RESULTS: The rs1128503 and rs2032582 SNPs modified the relationship between PSC and SERT-occupancy in both our intention-to-treat and sensitivity analyses at the carriership level. However, we could not detect significant differences in clinical response between any of the genetic subgroups. CONCLUSION: Pharmacokinetic influences of the ABCB1 rs1128503 and rs2032582 represent a potentially relevant pharmacogenetic mechanism to consider when evaluating paroxetine efficacy. Future studies are needed to support the role of ABCB1 genotyping for individualizing SSRI pharmacotherapy.

Obtaining granular activated carbon from paper mill sludge - A challenge for application in the removal of pharmaceuticals from wastewater.

In this work, a granular activated carbon (GAC) was produced using primary paper mill sludge (PS) as raw material and ammonium lignosulfonate (AL) as binder agent. PS is a residue from the pulp and paper industry and AL is a by-product of the cellulose pulp manufacture and the proposed production scheme contributes for their valorisation together with important savings in GAC precursors. The produced GAC (named PSA-PA) and a commercially available GAC (GACN), used as reference material, were physically and chemically characterized. Then, these materials were tested in batch experiments for the adsorption of carbamazepine (CBZ), sulfamethoxazole (SMX), and paroxetine (PAR) from ultra-pure water and wastewater. Even though GACN and PSA-PA possess very similar specific surface areas (SBET) (629 and 671 m2 g-1, respectively), PSA-PA displayed lower maximum adsorption capacities (qm) than GACN for the pharmaceuticals here studied (6 ±â€¯1-44 ±â€¯5 mg g-1 and 49 ±â€¯6-106 ±â€¯40 mg g-1, respectively). This may be related to the comparatively higher incidence of mesopores in GACN, which might have positively influenced its adsorptive performance. Moreover, the highest hydrophobic character and degree of aromaticity of GACN could also have contributed to its adsorption capacity. On the other hand, the performance of both GACs was significantly affected by the matrix in the case of CBZ and SMX, with lower qm in wastewater than in ultra-pure water. However, the adsorption of PAR was not affected by the matrix. Electrostatic interactions and pH effects might also have influenced the adsorption of the pharmaceutical compounds in wastewater.

Development of CT-guided biopsy sampling for time-dependent postmortem redistribution investigations in blood and alternative matrices--proof of concept and application on two cases.

The postmortem redistribution (PMR) phenomenon complicates interpretation in forensic toxicology. Human data on time-dependent PMR are rare and only exist for blood so far. A new method for investigation of time-dependent PMR in blood as well as in alternative body fluids and tissues was developed and evaluated using automated biopsy sampling. At admission of the bodies, introducer needles were placed in liver, lung, kidney, muscle, spleen, adipose tissue, heart, femoral vein, and lumbar spine using a robotic arm guided by a computed tomography scanner (CT). Needle placement accuracy was analyzed and found to be acceptable for the study purpose. Tissue biopsies and small volume body fluid samples were collected in triplicate through the introducer needles. At autopsy (around 24 h after admission), samples from the same body regions were collected. After mastering of the technical challenges, two authentic cases were analyzed as a proof of concept. Drug concentrations of venlafaxine, O-desmethylvenlafaxine, bromazepam, flupentixol, paroxetine, and lorazepam were determined by LC-MS/MS, and the percentage concentration changes between the two time points were calculated. Concentration changes were observed with both increases and decreases depending on analyte and matrix. While venlafaxine, flupentixol, paroxetine, and lorazepam generally showed changes above 30% and more, O-desmethylvenlafaxine and bromazepam did not undergo extensive PMR. The presented study shows that CT-controlled biopsy collection provides a valuable tool for systematic time-dependent PMR investigation, demanding only minimal sample amount and causing minimal damage to the body.

Paroxetine in Postmortem Fluids and Tissues from Nine Aviation Accident Victims.

Paroxetine is a selective serotonin reuptake inhibitor commonly prescribed for the treatment of depression, obsessive-compulsive disorder, panic disorder, social anxiety disorder and post-traumatic stress disorder. While the use of paroxetine is considered relatively safe, negative side effects, including nausea, drowsiness, insomnia and dizziness, can adversely affect a pilot's ability to safely operate an aircraft. The use of paroxetine may increase suicidal behavior and suicidal ideation. When relying on postmortem specimens for toxicological evaluation, a general understanding of drug distribution throughout postmortem specimens is important. This laboratory has determined the distribution of paroxetine in postmortem tissues and fluids from nine aviation accident fatalities. Specimens were processed using an n-butyl chloride liquid/liquid extraction followed by gas chromatographic/mass spectrometeric analysis. Blood paroxetine concentrations obtained from these cases ranged from 0.019 to 0.865 µg/mL. The distribution of paroxetine, expressed as mean specimen/blood ratio, was 1.67 ± 1.16 urine (n = 4), 0.08 ± 0.04 vitreous humor (n = 6), 5.77 ± 1.37 liver (n = 8), 9.66 ± 2.58 lung (n = 9), 1.44 ± 0.57 kidney (n = 8), 3.80 ± 0.69 spleen (n = 8), 0.15 ± 0.04 muscle (n = 8), 4.27 ± 2.64 brain (n = 7) and 1.05 ± 0.43 heart (n = 8). The large standard deviations associated with the paroxetine distribution coefficients suggest that paroxetine can experience significant postmortem concentration changes.

New validated HPLC methodology for the determination of (-)-trans-paroxetine and its enantiomer in pharmaceutical formulations with use of ovomucoid chiral stationary phase.

A new chromatographic method for the enantioseparation and the determination of (-)-trans-paroxetine and (+)-trans-paroxetine has been developed with the aid of amylose ovomucoid-based chiral stationary phase. The method is faster and five times more sensitive than procedures recommended previously: limit of detection and limit of quantification are 5 and 16 ng/mL, respectively [modified (Ferretti et al. in J Chromatogr B 710:157-164, 1998): 20 and 60 ng/mL]. It was carefully validated and applied for the determination of (-)-trans-paroxetine and (+)-trans-paroxetine in Parogen (Mc Dermott Laboratories Ltd.) and Xetanor (Actavis) coated tablets.

Pharmaceuticals and organic pollution mitigation in reclamation osmosis brines by UV/H2O2 and ozone.

One significant disadvantage of using reverse osmosis (RO) for reclamation purposes is the need to dispose of the RO retentates. These retentates contain a high concentration of micropollutants, effluent organic matter (EfOM) and other inorganic constituents, which are recalcitrant to biological treatment and may impact the environment. The occurrence of 11 pharmaceuticals (concentrations ranging from 0.2 to 1.6 µg L(-1)) and their mitigation in RO retentates by a UV/H2O2 process and ozonation was studied using a wide range of oxidant dosages. Eleven pharmaceuticals were identified at. Initial observed kinetic constants (kobs) were calculated for the different pharmaceuticals. Other typical wastewater parameters were also monitored during the UV/H2O2 and ozonation reactions. The range for kobs was found to be 0.8-12.8L mmol O3(-1) and 9.7-29.9 L mmol H2O2(-1) for the ozonation and UV/H2O2 process, respectively. For ozonation, Atenolol, Carbamazepine, Codeine, Trimethoprim and Diclofenac showed the lowest initial kobs (in the order mentioned). Atenolol and Carbamazepine appeared as the most ozone resistant pharmaceuticals, exhibiting the lowest percentage of elimination at low ozone doses. On the other hand, despite the non-selectivity of HO, differences in the initial kobs were also observed during the UV/H2O2 process. Trimethoprim, Paroxetine and Sulfamethoxazole exhibited the lowest initial kobs values (in the order mentioned). Trimethoprim and Paroxetine also exhibited the lowest percentage removal when low H2O2 doses were assayed. The compounds that were identified as problematic during ozonation were more efficiently removed by the UV/H2O2 process. UV/H2O2 generally appeared to be a more efficient technology for removing pharmaceuticals from RO brines compared to ozonation.

Paroxetine hydrochloride.

Paroxetine hydrochloride (3S-trans)-3-[(1,3-benzodioxol-5-yloxy)methyl]-4-(4-fluorophenyl)-piperidine hydrochloride (or (-)-(3S,4R)-(4-(p-fluorophenyl)-3-[[3,4-(methylenedioxy)-phenoxy]methyl]piperidine hydrochloride), a phenylpiperidine derivative, is a selective serotonin reuptake inhibitor. Paroxetine is indicated for the treatment of depression, generalized anxiety disorder, obsessive-compulsive disorder, panic disorder, posttraumatic stress disorder, and social anxiety disorder. The physicochemical properties, spectroscopic data (1D and 2D NMR, UV, FT-IR, MS, PXRD), stability, methods of preparation and chromatographic methods of analysis of pharmaceutical, and biological samples of paroxetine are documented in this review. Pharmacokinetics, metabolism, and pharmacological effects are also discussed.

Development and validation of a method for the analysis of paroxetine HCl by circular dichroism.

A simple, rapid, and sensitive method for the analysis of paroxetine, in tablets as well as the pure drug, by circular dichroism is described. The method was validated for repeatability, linearity, limit of detection, limit of quantification, and recovery according to the International Conference on Harmonization guidelines. Excellent results were obtained, within the globally accepted validation reference values, particularly taking into account the low concentration levels investigated. This is the first report of the quantitation of paroxetine, a chiral drug, without previous separation of the analyte. Additionally, the solid state CD spectrum of PXT was obtained.

Comparison of two extraction methods for the determination of selective serotonin reuptake inhibitors in sewage sludge by hollow fiber liquid-phase microextraction.

This paper presents two procedures for the determination of four selective serotonin reuptake inhibitors (citalopram, paroxetine, fluoxetine, and sertraline) and one metabolite (norfluoxetine) in sewage sludge utilizing three-phase hollow fiber liquid-phase microextraction (HF-LPME). First, direct HF-LPME was used for extraction, clean-up, and preconcentration. The pharmaceuticals were extracted from slurry samples into an organic phase and then back-extracted into an aqueous phase in the lumen of the hollow fiber. Second, a procedure combining pressurized hot water extraction and HF-LPME for clean-up and preconcentration was developed for the same analytes and matrix. The extracts were subsequently analyzed by liquid chromatography-mass spectrometry. For direct HF-LPME, limits of detection were between 1 and 12 ng g(-1) (dry weight) and the relative standard deviation (RSD) values were 3-12%. For the second method, limits of detection were approximately 6 ng g(-1) for all the compounds and RSD values were 8-12%. The methods were validated by comparison of results for the same samples. Sewage sludge from a Swedish wastewater treatment plant was analyzed by both methods; average concentrations were similar for citalopram, paroxetine, and fluoxetine with values of approximately 530, 40, and 200 ng g(-1) , respectively.

A simple HPLC method for the simultaneous determination of two selective serotonin reuptake inhibitors and two serotonin-norepinephrine reuptake inhibitors in hair, nail clippings, and cerebrospinal fluid.

A novel and simple high-performance liquid chromatography method has been developed for the simultaneous determination of two selective serotonin reuptake inhibitors (fluoxetine and paroxetine) and two serotonin-norepinephrine reuptake inhibitors (venlafaxine and duloxetine) in alternative samples of toxicological interest such as hair, nail clippings, and cerebrospinal fluid (CSF). The separation was achieved on a Hichrom Kromasil 100-5C(18) (250 × 4.6 mm) 5 µm column by using ammonium acetate (0.05 M)-acetonitrile (59:41% v/v) as the mobile phase, delivered isocratically at a flow rate of 1.3 mL/min, within ca. 10 min. Ultraviolet detection at 235 nm was used for monitoring the eluting analytes. Validation was performed in terms of linearity, selectivity, accuracy, precision, and stability. Correlation coefficients were greater than 0.9954. The limits of quantitation ranged between 0.3 and 2.1 ng/µL for all analytes in the liquid matrix (CSF), while the respective values were in the range of 0.3-3.6 ng/mg for solid matrices (hair and nail clippings), with an injection volume of 20 µL. Repeatability and intermediate precision (relative standard deviation, RSD%) were less than 16.6%. The method was successfully applied to actual hair and nail samples from a patient under fluoxetine treatment.

Spectrofluorimetric determination of paroxetine HCl in pharmaceuticals via derivatization with 4-chloro-7- nitrobenzo-2-oxa-1,3-diazole (NBD-Cl).

A sensitive and simple spectrofluorimetric method has been developed and validated for the determination of the antidepressant paroxetine HCl (PXT) in its dosage forms. The method was based on coupling reaction of PXT with 4-chloro-7-nitrobenzo-2- oxa-1,3-diazole (NBD-Cl) in an alkaline medium (pH 8) to form a highly fluorescent derivative that was measured at 530 nm after excitation at 460 nm. The factors affecting the formation and stability of the reaction product were carefully studied and optimized. The fluorescence-concentration plot is rectilinear over the range 0.2-6 µg/mL with LOD of 0.08 µg/mL and LOQ of 0.24 µg/mL respectively. The method was applied to the analysis of commercial tablets and the results were in good agreement with those obtained using the reference method. The mean percentage recoveries for paxetin and xandol tablets were 101.27 ± 1.79 and 101.33 ± 1.19 respectively. A proposal of the reaction pathway was postulated.

A study on the mechanisms by which minocycline protects against MDMA ('ecstasy')-induced neurotoxicity of 5-HT cortical neurons.

3,4-Methylenedioxymethamphetamine (MDMA, 'ecstasy') is a selective 5-HT neurotoxin in rat brain which has been shown to produce acute neuroinflammation characterized by activation of microglia and release of interleukin-1beta (IL-1beta). We aimed to determine whether or not minocycline, a semi-synthetic tetracycline antibiotic capable of inhibiting microglial activation, could prevent the inflammatory response and reduce the toxicity induced by MDMA. Adult male Dark Agouti rats were given minocycline twice a day for 2 days (45 mg/kg on the first day and 90 mg/kg on the second day; 12-h apart, i.p.). MDMA (12.5 mg/kg; i.p.) was given after the third minocycline injection and animals were killed either 1 h later for the determination of NFkappaB binding activity, 3 h later for the determination of IL-1beta, 24 h later for the determination of microglial activation or 7 days later for the determination of [(3)H]-paroxetine binding as a measure of 5-HT neurotoxicity. MDMA increased NFkappaB activation, IL-1beta release and microglial activation both in the frontal cortex and in the hypothalamus and 7 days later produced a reduction in the density of 5-HT uptake sites in both these brain areas. Minocycline prevented the MDMA-induced increase in NFkappaB activation, IL-1beta release and microglial activation in the frontal cortex and prevented the 5-HT neurotoxicity 7 days later. However, in the hypothalamus, in spite of preventing MDMA-induced microglial activation, minocycline failed to prevent MDMA-induced NFkappaB activation, IL-1beta release and neurotoxicity. This suggests that the protective mechanism of minocycline against MDMA-induced neurotoxicity in frontal cortex involves inhibition of MDMA-induced NFkappaB activation possibly through a reduction in IL-1beta signalling.

New nonextractive and highly sensitive high-performance liquid chromatographic method for determination of paroxetine in plasma after offline precolumn derivatization with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole.

New nonextractive and simple offline precolumn derivatization procedures have been proposed, for the first time, for the trace determination of paroxetine (PXT) in human plasma by HPLC with fluorescence detection. Trimetazidine (TMZ) was used as an internal standard. Plasma samples were treated with acetonitrile for protein precipitation and then derivatized with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole in borate buffer of pH 8 at 70 degrees C for 30 min. Separations of the derivatized PXT and TMZ were performed on a Nucleosil CN column using a mobile phase consisting of acetonitrile-10 mM sodium acetate buffer (pH 3.5)-methanol (47 + 47 + 6, v/v) at a flow rate of 1.0 mL/min. The derivatized samples were excited at 470 nm and monitored at an emission wavelength of 530 nm. Under the optimum chromatographic conditions, a linear relationship with good correlation coefficient (r = 0.9998, n = 7) was found between the peak area ratio and PXT concentrations in the range of 5-600 ng/mL. The LOD and LOQ were 1.37 and 4.14 ng/mL, respectively. The intraday and interassay precisions were satisfactory; the RSD did not exceed 4.2%. The accuracy of the method was proved by recovery of PXT from spiked human plasma at levels of 97.28-104.38 +/- 0.41-3.62%. The proposed method had high throughput, as the analysis involved a simple sample pretreatment procedure and short run time (< 10 min). The results demonstrated that the method would have a great value when it is applied in the therapeutic monitoring of PXT.

Depletion of selective serotonin reuptake inhibitors during sewage sludge composting.

Sewage and sewage sludge is known to contain pharmaceuticals, and since sewage sludge is often used as fertilizer within agriculture, the reduction of the selective serotonin reuptake inhibitors (SSRIs) Citalopram, Sertraline, Paroxetine, Fluvoxamine and Fluoxetine during composting has been investigated. Sewage sludge was spiked with the SSRIs before the composting experiment started, and the concentration of the SSRIs in the sludge during a 21 day composting period was measured by liquid phase microextraction (LPME) and high-performance liquid chromatography-mass spectrometry. All the SSRIs had a significant decrease in concentration during the composting process. The highest reduction rates were measured for Fluoxetine and Paroxetine and the lowest for Citalopram. In addition three out of four known SSRI metabolites were found in all the samples, and two of them showed a significant increase in concentration during the composting period.

Rapid HPLC method for the simultaneous monitoring of duloxetine, venlaflaxine, fluoxetine and paroxetine in biofluids.

A simple and rapid HPLC method is developed for the determination of two serotonin-norepinephrine-reuptake inhibitors (duloxetine and venlaflaxine) and two selective serotonin-reuptake inhibitors (fluoxetine and paroxetine) in human biofluids. Separation was performed on an Inertsil ODS-3 column (250 x 4.0 mm, 5 µm) with acetonitrile-ammonium acetate (0.05 M, 41:59 v/v) at 235 nm, within 7 min. SPE on Oasis(®) HLB cartridges was applied for the isolation of analytes from biofluids. The developed methodology was validated in terms of sensitivity, linearity, accuracy, precision, stability and selectivity. Relative standard deviation was less than 10.4%. Limit of detection was 0.2-0.6 ng/µl in blood plasma and 0.1-0.8 ng/µl in urine. The method was successfully applied to biofluids from a patient under duloxetine treatment.

Death from undiagnosed glioblastoma multiforme and toxic self-medication presenting with concurrent dysfunctional behavior.

We encountered a decedent with an unexpected glioblastoma multiforme. A 61-year-old retired African-American woman was found dead in her home, fully clothed in her bathtub, with a pillow under her head. At autopsy, the brain showed a glioblastoma multiforme. Toxicology showed elevated hydrocodone, propoxyphene, acetaminophen, and positive paroxetine. The presence of a brain tumor likely caused a severe headache. The use of her medications could have indicated a reaction to the escalating pain of the brain trauma, and overuse could be consistent with escalating pain or loss of rational thought processes. The present case is interesting in that it had evidence of behavioral dysfunction that could be related to the brain tumor, and death arising from the glioblastoma multiforme (cerebral hemorrhage and edema) with concurrent multiple drug intoxication.

Stability-indicating high performance thin layer chromatography determination of Paroxetine hydrochloride in bulk drug and pharmaceutical formulations.

A simple selective precise and stability-indicating high performance thin layer chromatographic method of analysis of Paroxetine hydrochloride both as a bulk drug and in formulations was developed and validated. The method employed TLC (Thin Layer Chromatography) aluminum precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of butanol:acetic acid:water (8:2:0.5, v/v/v). This system was found to give compact spots for Paroxetine HCl (Rf, retardation factor, value-0.48+/-0.02). Paroxteine HCl was subjected to acid and alkali hydrolysis, oxidation and photodegradation, where the degraded product was well separated from the pure drug. Densitometric analysis of Paroxetine hydrochloride was carried out in the absorbance mode at 295 nm. The linear regression analysis data for the calibration spots showed good relationship with (regression) r2 = 0.9903 in the amount range of 300-1500 ng (nanogram) per spot. The mean value of co-relation co-efficient, slope and intercept were 0.9903+/-0.001, 5.38+/-0.058 and 182.5+/-2.16 respectively. The method was validated for precision, recovery and robustness. The limits of detection and quantitation were 50 and 150 ng, respectively. The drug does not undergo degradation with oxidation, but gets affected in acidic and alkaline conditions. The acid and alkali degradation showed extra peaks at 0.4 and 0.08 Rf, respectively. This indicates that the drug is susceptible to acidic and alkaline medium. As the method could effectively separate the drug from its degradation products, it can be employed as a stability-indicating one.

Analysis of paroxetine, fluoxetine and norfluoxetine in fish tissues using pressurized liquid extraction, mixed mode solid phase extraction cleanup and liquid chromatography-tandem mass spectrometry.

Recent studies have shown that selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine are accumulated in the tissues of fish as a result of discharges of pharmaceuticals into surface waters from municipal wastewater treatment plants. In this study, an analytical method based on liquid chromatography with atmospheric pressure chemical ionization and tandem mass spectrometry (LC-APCI-MS/MS) was developed and validated for the determination of residues of paroxetine, fluoxetine and its active metabolite, norfluoxetine, in fish tissue. The procedure for sample preparation includes extraction of tissue by pressurized liquid extraction (PLE), followed by cleanup on a mixed-mode solid phase extraction (SPE) cartridge, Oasis MCX. With the optimized method, matrix interferences were reduced and recoveries >85% were obtained. The limits of quantitation (LOQ) determined by analysis of spiked fish tissue were 0.24, 0.07, and 0.14 ng/g wet weight for paroxetine, fluoxetine and norfluoxetine, respectively. This method was successfully applied to the analysis of samples of fish collected from Hamilton Harbour in Ontario, Canada, which is an urbanized and industrialized embayment of Lake Ontario. These analyses showed that the three analytes were present in fish tissues at concentrations up to approximately 1 microg/kg wet weight.