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A high-performance imipramine (IMPR) sensor has been developed  based on metal chalcogenide-carbon composite materials. The antimony telluride-graphite nanofiber (Sb 2 Te 3 -GNF, hereafter SBT-GNF) composite was synthesized by the hydrothermal method and confirmed by X-ray powder diffraction (XRD) pattern. The morphology, crystalline lattice, and chemical states were characterized by HRTEM, SAED, and XPS analysis. The characterizations confirmed the formation of an effective composite, SBT-GNF. The SBT-GNF was fabricated as a disposable sensor electrode with a screen-printed carbon electrode (SPCE) and examined for the detection of IMPR by differential pulse voltammetry (DPV). The electroanalytical results of SBT-GNF are compared with the SBT and GNF, and the rational design of effective composite is discussed. SBT-GNF/SPCE showed a good linear range (0.01‑51.8 μM), sensitivity (1.35 ± 0.1 μA μM -1  cm -2 ), and low LOD (4 ± 2 nM). Moreover, the SBT-GNF/SPCE revealed high selectivity and high tolerance limit against potential interfering compounds in blood serum and urine samples. Therefore, this electrochemical sensor can be applicable for the detection of tricyclic antidepressant drug IMPR in clinical and pharmaceutical analysis.

We developed a biomineral-inspired hybrid material composed of CaCO3 and an organic polymer as a column packing material for HPLC. This material combines a hierarchical mesoporous structure and the functionality of the polymer. The surface of monodispersed mesoporous CaCO3 microspheres was modified with poly(maleic acid-alt-1-octadecene) (PMAcO) comprising hydrophobic alkyl chains and anionic carboxylate groups. PMAcO adsorbed onto the surface of CaCO3 through electrostatic interaction between Ca2+ sites and carboxylate groups, resulting in an octadecene coated microsphere interface. These microspheres were applied as a HPLC column and exhibited reversed-phase retention behavior in the separation of alkylbenzenes. This column showed high alkaline mobile phase resistance compared with the conventionally applied ODS column packing material. Quantitative analysis of the basic antidepressants clomipramine and imipramine spiked into whole blood was achieved with an alkaline mobile phase, demonstrating the potential of the biomineral-inspired material as a HPLC stationary phase for practical applications in routine analyses of basic drugs requiring alkaline mobile phases.

A novel, sensitive, rapid, and simple fluorescent probe has been developed based on green-synthesized carbon dots (CDs). In this work, CDs have been synthesized from valerian root by hydrothermal method. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) results confirm the formation of CDs with sizes of less than 10 nm. Fluorescence quenching of CDs was due to the aggregation of the negative charges of CDs with the positive charge of imipramine (IMI) and was then used as the signal for determination of IMI. In addition, the cytotoxicity of CDs was determined using the MTT assay. The probe responses under optimum conditions were linear in the range of 1.0-200.0 ng mL -1 with a limit of detection of 0.6 ng mL -1 . Afterwards, mesoporous boehmite (MB) was modified with synthesized CDs (CDs/MB). TEM images confirmed MB modification with CDs. In this case, the variations in the fluorescence signal for different concentrations of IMI increased leading to the higher sensitivity for IMI detection. The limit of detection and linear range for determination of IMI with CDs/MB were obtained as 0.2 and 0.5-200.0 ng mL -1 , respectively. To evaluate the fluorescent probe, IMI was measured in real samples. Graphical abstract.

In current work the Fe 3 O 4 magnetic nano-particles anchored to core-shells of SiO 2 which grafted by C 8 /NH 2 dual mixed groups, have been synthesized. The magnetic nano-particles were characterized by scanning electron microscopy, X-ray diffraction spectroscopy, and zeta-potential reader. The resulted nano-particles have spherical structure with diameters in the range of 105 to 110 nm. A magnetic solid phase extraction method was developed for extraction of imipramine and desipramine from human plasma samples under ultrasonic conditions by using of prepared NPs as sorbent. The MNPs were dispersion in plasma under sonicated conditions, accumulated by an external magnetic field and washed with Briton-Robinson buffer-acetonitrile solution (0.05 mol l -1 , pH = 5, 10%V/V). The drugs were removed by methanol and quantified by gas chromatography. The calibration curves (correlation coefficient > 0.99) for IMP and DES were linear in the concentration range of 0.005 to 5 and 0.01 to 4 μg ml -1 , respectively. The LOD, LOQ, intra and inter-day precision values were measured too. The proposed Fe 3 O 4 /SiO 2 /C 8 /NH 2 MNPs could be applied for 3.0 times., (Copyright © 2018. Published by Elsevier B.V.)

Objective: The aim of this study was to explore the serum concentration-effect relation for first-line drugs in neuropathic pain and to determine if efficacy could be increased., Methods: Data from a randomized, placebo-controlled, cross-over trial on imipramine, pregabalin, and their combination in painful polyneuropathy were used. Treatment periods were of 4 weeks' duration, outcome was the weekly median of daily pain rated by a 0 to 10 numeric scale, and drug concentrations were determined by high-performance liquid chromatography., Results: In 47 patients, pain was reduced -1.0 (95% confidence interval [CI], -1.5 to -0.6) by imipramine, -0.4 (95% CI, -0.9 to 0.1) by pregabalin, and -1.6 (95% CI, -2.1 to -1.1) by combination therapy. On monotherapy, there was no difference between responders and nonresponders with respect to concentrations of imipramine (mean, 161 vs. 229 nmol/L, P=0.129) and pregabalin (mean, 9.8 vs. 11.7 μmol/L, P=0.178). There was no correlation between drug concentration and pain reduction for imipramine (r=0.17, P=0.247), whereas there was a marginally, positive correlation for pregabalin (r=0.28, P=0.057). There was no interaction between treatment and concentration classes (imipramine < or ≥100 nmol/L, pregabalin < or ≥10 μmol/L) either for monotherapy or for combination therapy (P=0.161 to 0.797). Isobolographic presentations of reponders with imipramine and pregabalin concentrations during combination therapy did not indicate synergistic interaction., Discussion: There were no important relations between drug concentrations and efficacy, or indication of synergistic interaction between the drugs. It was not concluded that treatment can be improved by measurement of drug concentration of pregabalin.

A rapid and sensitive ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometric (UHPLC-Q-TOF-MS) method was developed for quantification of imipramine, one of the most widely used tricyclic antidepressants, and desipramine, an active metabolite of imipramine, in mouse serum. The developed method included a simple protein precipitation with acetonitrile in 50 μL of serum and analyte separation on an Acquity UPLC BEH C18 column using a gradient elution of acetonitrile with 0.1% formic acid and 20 mM ammonium formate. As a result, the entire analysis time was <20 min including the sample preparation and the LC-MS analysis. The limit of quantification was 5.0 ng mL(-1) for both imipramine and desipramine, and calibration curves were linear over the concentration range of 5.0-1,000.0 and 5.0-250.0 ng mL(-1) for imipramine and desipramine, respectively. Intraday precisions at three levels were 2.2-3.6 and 1.7-4.2% for imipramine and desipramine, respectively, whereas interday precisions were 2.6-5.0 and 2.0-8.4% for imipramine and desipramine, respectively. Accuracy ranged between 93.6 and 106.6% for imipramine and 94.1 and 106.4% for desipramine. Absolute recovery was 96.0-97.6% for imipramine and 87.0-99.5% for desipramine. Finally, the described method was applied to mice administered with imipramine, demonstrating the suitability for quantification of imipramine and desipramine for therapeutic drug monitoring or bioequivalence studies., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Tricyclic antidepressants (TCA) are used to treat major depressive disorder and other psychological conditions. The efficacy of these drugs is tied to a narrow therapeutic window. Inappropriately high drug concentrations can result in serious side effects such as hypotension, tachycardia, or coma. As a result, concentrations of tricyclic antidepressants are routinely monitored to ensure compliance and to prevent adverse side effects by dose adjustments. We describe a method for the determination of concentrations of amitriptyline, desipramine, imipramine, and nortriptyline in human serum using high-performance liquid chromatography coupled to a tandem mass spectrometer with electrospray ionization (HPLC-ESI-MS/MS). The method is rapid, requiring only 3.5 min per analysis. The method requires 100 μL of serum. Concentrations of each TCA were quantified by a calibration curve relating the peak area ratio of each TCA analyte to a deuterated internal standard (amitriptyline-D3, desipramine-D3, imipramine-D3, and nortriptyline-D3). The method was linear from ~70 ng/mL to ~1000 ng/mL for all TCAs, with imprecision ≤ 12%.

This paper describes a sample preparation method that complements a previously published liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for acetaminophen and eight structurally-related compounds in human serum (C. Bylda, R. Thiele, U. Kobold, D.A. Volmer. Drug Test. Anal. 2014, 6, 451). The analytes (acetaminophen [APAP] + metabolites acetaminophen-glucuronide [APG], -cysteine [APC], -mercapturate [APM] and -cysteine [APC], structurally similar analogues phenacetin and p-phenetidine, as well as tricyclic antidepressants imipramine and amitryptiline) were extracted from serum using magnetized hyper-crosslinked polystyrene particles. The sample preparation protocol was developed by means of a design of experiments (DoE) statistical approach. Using three representative compounds from the analyte panel with different polarities (high, medium, and low), two screening designs were used to identify factors that exhibited significant impact on recovery of the analytes. These parameters were then optimized to permit extraction of the complete target panel exhibiting a broad range of chemical polarities. Liquid chromatographic separations were achieved by gradient elution using a pentafluorphenyl column with subsequent detection by electrospray ionization-triple quadrupole mass spectrometry in multiple reaction monitoring (MRM) mode. The method was linear over the range 0.1-100 µg/mL for APAP, APG, p-phenetidine and phenacetin, 0.03-50 µg/mL for APS, and 0.01-10 µg/mL for APM, APC, imipramine and amitriptyline, with R(2)  > 0.99. The assay exhibited good precision with CVs ranging from 2 to 9% for all analytes; the accuracy was assessed by comparing two LC-MS/MS methods using a set of 68 patient samples., (Copyright © 2014 John Wiley & Sons, Ltd.)

Therapeutic drug monitoring (TDM) of tricyclic antidepressants (TCAs) is considered useful in patients with major depressive disorder, since these drugs display large individual differences in clearance, and the therapeutic windows of these drugs are relatively small. We developed an assay for determination of amitriptyline (ATP), nortriptyline (NTP), imipramine (IMP), desipramine (DSP) clomipramine (CMP) and desmethyl-clomipramine (DCMP) in dried blood spots (DBS). A fast and robust LC-MS/MS method was developed and analytically validated for simultaneous determination of ATP, NTP, IMP, DSP, CMP, and DCMP in DBS. Six mm circles were punched out from DBS collected on Whatman DMPK-C paper and mixed with acetonitrile: methanol 1:3 containing the internal standard. The extract was analyzed by LC-MS/MS. Total LC-MS/MS runtime was 4.8 min. The assay was linear in the range 20-500 µg/L for all compounds. Overall-assay accuracy and precision were<20% for the lower limit of quantification (LLOQ), except for CMP (CV=22.3%), and <15% at other concentrations. The initial LLOQ was 20 µg/L however for CMP and DMCP it was increased to 40 µg/L. The blood volume per spot did not influence the results, but a low hematocrit (≤ 30%) was associated with a >15% negative bias for all compounds. Punching at the perimeter of the blood spot instead of the center was associated with a positive bias. A good correlation was found between patients plasma and DBS samples of ATP, NTP and DMCP, but not for CMP. In addition, proportional differences were found. This LC-MS/MS method was analytically validated for determination of TCAs in DBS. Future validation will focus on the clinical application of the method., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A liquid chromatography coupled with tandem mass spectrometry method for the quantification of the antispasmodic drug drotaverine in human plasma was developed and validated according to the current bioanalytical guidelines. The internal standard used was imipramine. The separation was performed on a Kinetex C18 50×3mm, 2.6μm column under isocratic conditions using a mobile phase of 65:35 (v/v) formic acid 0.2% (v/v) in water and acetonitrile at 40°C with a flow rate of 0.4ml/min. The detection of drotaverine and the internal standard was performed in multiple reaction monitoring (MRM) mode using an ion trap mass spectrometer with electrospray ionization, operating in positive mode. The human plasma samples (0.24ml) were deproteinized with methanol and aliquots of 4μl from supernatants obtained after centrifugation were directly injected into the chromatographic system. The method shows a good linearity (r(2)>0.997), precision (CV<6.3%) and accuracy (bias<5.4%) over the range of 2.24-448ng/ml drotaverine in plasma. The recovery was between 91 and 98%. The limit of quantification was 2.24ng/ml. The analysis required only a 3.0min run. The developed and validated method for the determination of drotaverine in human plasma was successfully applied in a bioequivalence study, for analyzing approximately 1000 subject's samples., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The method described in this study allows the simultaneous quantification of acetaminophen (APAP) and nine structurally related compounds, namely acetaminophen metabolites and structurally similar analogs (acetaminophen-glucuronide [APG], -sulfate [APS], mercapturate [APM], -cysteine [APC], p-phenetidine, phenacetin), antidote (N-acetylcysteine, NAC), and two tricyclic antidepressants (imipramine and amitryptiline). Due to the relatively high serum concentration levels in the µg/ml range, matrix effects were simply minimized by dilution. The samples were diluted with water and disulfide bonds between serum proteins and analytes reduced using tris(2-carboxyethyl)phosphine. Chromatographic separation of the analytes was achieved by gradient elution using a pentafluorphenyl (PFP) column with subsequent detection by electrospray ionization (ESI) triple quadrupole mass spectrometry in positive and negative ionization multiple reaction monitoring (MRM) modes. Quantification was performed by means of deuterated analogues of the analytes as internal standards. Total run time of the assay was 19 min. The method was fully validated and allowed quantification of the analytes with lower limits of quantification between 50 and 0.5 ng/ml. The calibration curves were linear over the range 0.1-100 µg/ml for APAP, APG, NAC, p-phenetidine and phenacetin, 0.03-50 µg/ml for APS, and 0.01-10 µg/ml for APM, APC, imipramine and amitriptyline with correlation coefficients r(2)  > 0.99. The intra-assay precision was ≤5% for all analytes except NAC (CV < 10%). The inter-day precision was ≤10% for all analytes except NAC (inter-assay precision <11%). This method was used to analyze 77 patient and spiked samples and results were consistent with expected values from a round robin test., (Copyright © 2013 John Wiley & Sons, Ltd.)

Objective: To compare the efficacy of plasma level-targeted dose imipramine and high-dose venlafaxine in depressed inpatients in a randomized double-blind study., Methods: The study included 85 patients with a diagnosis of major depressive episode according to the DSM IV criteria and a 17-item Hamilton Rating Scale for Depression (HAM-D) score ≥ 17. Patients were randomized to imipramine or venlafaxine. The dose of imipramine was adjusted for each patient to a predefined blood level of 200-300 ng/ml. The dose of venlafaxine was increased gradually to 300-375 mg/day. Efficacy was evaluated after 7 weeks of treatment., Results: The mean age of the study group was 54.5 (range 29-82) years. There was no significant difference according to the primary outcome criterion of a ≥50% reduction on the HAM-D score: 17 of 43 (39.5%) patients on imipramine were responders compared to 21 of 42 (50%) patients on venlafaxine. When considering remission as outcome criterion (HAM-D score ≤ 7), 10 of 43 (23.3%) patients on imipramine were remitters compared to 15 of 42 (35.7%) patients on venlafaxine; again, no significant difference. When analysing a subpopulation of patients without psychotic features, with remission as outcome criterion, a significant difference was found: 5 of 34 (14.7%) patients on imipramine were remitters compared to 12 of 31 (38.7%) patients on venlafaxine., Conclusions: The present study used optimal doses in depressed inpatients and showed that venlafaxine is at least equal in efficacy to imipramine. The results in the subgroup without psychotic features indicate a possible superiority of venlafaxine., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

An Amberlite XAD-2 (XAD2) and titanium dioxide nanoparticles (TNPs) modified glassy carbon paste electrode (XAD2-TNP-GCPE) was developed for the determination of imipramine (IMI), trimipramine (TRI) and desipramine (DES). The electrochemical behavior of these molecules was investigated employing cyclic voltammetry (CV), chronocoulometry (CC), electrochemical impedance spectroscopy (EIS) and adsorptive stripping differential pulse voltammetry (AdSDPV). After optimization of analytical conditions using a XAD2-TNP-GCPE electrode at pH 6.0 phosphate buffer (0.1 M), the peak currents were found to vary linearly with its concentration in the range of 1.30 × 10(-9) to 6.23 × 10(-6) M for IMI, 1.16 × 10(-9) to 6.87 × 10(-6) M for TRI and 1.43 × 10(-9) to 5.68 × 10(-6) M for DES. The detection limits (S/N = 3) of 3.93 × 10(-10), 3.51 × 10(-10) and 4.35 × 10(-10) M were obtained for IMI, TRI and DES respectively using AdSDPV. The prepared modified electrode showed several advantages such as a simple preparation method, high sensitivity, very low detection limits and excellent reproducibility. The proposed method was employed for the determination of IMI, TRI and DES in pharmaceutical formulations, blood serum and urine samples.

Background and Purpose: Recent studies indicate that efflux of antidepressants by the multidrug resistance transporter P-glycoprotein (P-gp) at the blood-brain barrier (BBB) may contribute to treatment-resistant depression (TRD) by limiting intracerebral antidepressant concentrations. In addition, clinical experience shows that adjunctive treatment with the P-gp inhibitor verapamil may improve the clinical outcome in TRD. Therefore, the present study aimed to investigate the effect of P-gp inhibition on the transport of the tricyclic antidepressant imipramine and its active metabolite desipramine across the BBB., Experimental Approach: Intracerebral microdialysis in rats was used to monitor brain levels of imipramine and desipramine following i.v. imipramine administration, with or without pretreatment with one of the P-gp inhibitors verapamil or cyclosporin A (CsA). Plasma drug levels were also determined at regular intervals., Key Results: Pretreatment with either verapamil or CsA resulted in significant increases in imipramine concentrations in the microdialysis samples, without altering imipramine plasma pharmacokinetics. Furthermore, pretreatment with verapamil, but not CsA, led to a significant elevation in plasma and brain levels of desipramine., Conclusions and Implications: The present study demonstrated that P-gp inhibition enhanced the intracerebral concentration of imipramine , thus supporting the hypothesis that P-gp activity restricts brain levels of certain antidepressants, including imipramine. These findings may help to explain reports of a beneficial response to adjunctive therapy with verapamil in TRD., (© 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.)

Recent advances in electromembrane extraction (EME) methodology calls for effective and accessible detection methods. Using imipramine and clomipramine as model therapeutics, this proof-of-principle work combines EME with gas chromatography analysis employing a flame ionization detector (FID). The drugs were extracted from acidic aqueous sample solutions, through a supported liquid membrane (SLM) consisting of 2-nitrophenyl octyl ether (NPOE) impregnated on the walls of the hollow fiber. EME parameters, such as SLM composition, type of ion carrier, pH and the composition of donor and acceptor solutions, agitation speed, extraction voltage, and extraction time were studied in detail. Under optimized conditions, the therapeutics were effectively extracted from different matrices with recoveries ranging from 90 to 95%. The samples were preconcentrated 270-280 times prior to GC analysis. Reliable linearity was also achieved for calibration curves with a regression coefficient of at least 0.995. Detection limits and intra-day precision (n=3) were less than 0.7 ng mL(-1) and 8.5%, respectively. Finally, method was applied to determination and quantification of drugs in human plasma and urine samples and satisfactory results were achieved., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Situations in which multiple outcomes and predictors of different distributional types are collected are becoming increasingly common in biopharmaceutical practice, and joint modeling of mixed types has been gaining popularity in recent years. Evaluation of various statistical techniques that have been developed for mixed data in simulated environments necessarily requires joint generation of multiple variables. This article is concerned with building a unified framework for simulating multiple binary and normal variables simultaneously given marginal characteristics and association structure via combining well-established results from the random number generation literature. We illustrate the proposed approach in two simulation settings where we use artificial data as well as real depression score data from psychiatric research, demonstrating a very close resemblance between the specified and empirically computed statistical quantities of interest through descriptive and model-based tools.

The potential use of surface Raman enhanced spectroscopy (SERS) for confirmatory identification and the semi-quantitative analysis of selected tricyclic antidepressants (TCAs) is examined utilizing a conventional silver colloid. Raman and SERS spectra of aqueous solutions of imipramine (Imi) and its metabolite, desipramine (Des), were recorded as the function of concentration using NIR excitation. A good linear correlation is observed for the dependence of the SERS signal at 684 cm(-1) (R(2) = 0.9997) on Imi concentration over the range of 0.75-7.5 μM. The limit of detection of imipramine in the silver colloidal solution is 0.98 μM. SERS spectra of Imi and Des were also recorded for blood plasma samples without prior purification as well as after the use of standard solid phase extraction. All spectra show the characteristic spectral profile of the molecules and moreover, stronger signal enhancement is observed for Imi in the "raw" samples as opposed to Imi extracted from a biological matrix.

Background: A new concept for simple and generic automation of dried blood spot (DBS) analysis is evaluated. Flow-through desorption of the blood spot is coupled online to SPE and MS/MS without using a LC column. Blood, spiked with a mixture of test compounds is spotted on paper, dried and then desorbed by means of a prototype clamping device., Results: Conditions for extraction and chromatography on a single SPE cartridge were optimized with respect to clean-up, separation and ionization suppression. Addition of internal standard using loop-injection upstream of the clamped blood spot was examined and proved to be simple and reliable. Validation results for the 1-1000 ng/ml range are well within acceptance criteria for bioanalysis., Conclusion: Results demonstrate feasibility of the DBS SPE-MS/MS concept for efficient automation of the entire DBS analysis workflow.

Nanoflow liquid chromatography/mass spectrometry (nano-LC/MS) has attracted increasing interest in virtue of high sensitivity, low sample consumption, and minimal matrix effect. In this work a HPLC-Chip/quadrupole time-of-flight (Q-TOF) MS device with a new ultra-high capacity small molecule chip (UHC-Chip) which features a 500 nL enrichment column and a 150 mm × 75 μm analytical column, was evaluated with a drug mixture covering a wide range of polarities. Excellent chromatographic precision with 0.1-0.5% RSD for retention time and 1.7-9.0% RSD for peak area, low limit of detection, good chip-to-chip reproducibility and linearity were obtained by using this UHC-Chip. Compared with the standard HPLC-Chip with 40 nL trapping column, the UHC-Chip showed higher enrichment capability and hence gave a higher response in signal detection. Additionally, 4-30 times increase in sensitivity was obtained compared with conventional LC/MS, which indicated that UHC-Chip/MS was a valuable tool for the quantitative analysis of low level impurities and degradation products in pharmaceuticals. Moreover, satisfactory results obtained from trace drug analysis of serum samples further proved its practicality and potential for use in drug testing and development., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Milnacipran is a specific serotonin and norepinephrine reuptake inhibitor, which has been widely used against major depressive episodes. In this study, cardiovascular effects of milnacipran were assessed in comparison with those of a typical tricyclic antidepressant imipramine using the halothane-anesthetized dogs. Milnacipran (n = 6) or imipramine (n = 6) was intravenously administrated in three escalating doses of 0.1, 1 and 10 mg/kg over 10 min with a pause of 20 min between the doses. Clinically relevant plasma concentrations were obtained after 0.1-1 mg/kg of milnacipran in this study, whereas therapeutic dose and plasma concentration of imipramine were reported to be similar to those of milnacipran. The low and middle doses of milnacipran hardly affected cardiohemodynamic or electrophysiological variables except that they slightly increased vascular tone and ventricular contraction, whereas same doses of imipramine delayed repolarization process without affecting the other variables. The high dose of both milnacipran and imipramine induced similar extent of negative chronotropic, inotropic and dromotropic effects together with vasoconstriction and repolarization delay. Thus, the effects of milnacipran may be more selective for cardiohemodynamics than for repolarization delay, whereas reverse will be true for imipramine, supporting lack of clinical report of patients with milnacipran-induced long QT syndrome unlike imipramine.

CYP2C19 converts the tricyclic antidepressant imipramine to its active metabolite desipramine, which is subsequently inactivated by CYP2D6. The novel CYP2C19*17 allele causes ultrarapid metabolism of CYP2C19 substrates. We genotyped 178 depressed patients on imipramine for CYP2C19*17, and measured steady-state imipramine and desipramine plasma concentrations. Mean dose-corrected imipramine plasma concentration was significantly dependent on CYP2C19 genotype (Kruskal-Wallis test, P=0.01), with circa 30% lower levels in CYP2C19*17/*17 individuals compared with CYP2C19*1/*1 (wild-type) patients. The mean dose-corrected imipramine+desipramine plasma concentrations and imipramine/desipramine ratios were not significantly different between genotype subgroups (Kruskal-Wallis tests, P>or=0.12). In a multivariate analysis, we found a significant, but limited effect (P=0.035, eta(2)=0.031) of the CYP2C19*17 genotype on imipramine+desipramine concentrations. Although the CYP2C19*17 allele is associated with a significantly increased metabolism of imipramine, CYP2C19*17 genotyping will, in our view, not importantly contribute to dose management of patients on imipramine therapy guided by imipramine+desipramine plasma concentrations.

Depression and anxiety frequently occur together or in extension of each other. According to a previous study in depressed inpatients, a high trait anxiety level correlated with a positive response to the diazepam test (DT) and a low trait anxiety level with a negative response to the test. The aim of this study is to investigate whether positive reaction to the DT is related to a positive response to fluvoxamine and whether a negative reaction to the test is related to positive response to imipramine. The DT was performed in 130 patients diagnosed with a depressive disorder. Following the DT, the patients were randomly assigned to double-blind treatment with either imipramine or fluvoxamine. Doses of both antidepressants were adjusted to attain predefined blood levels, and the outcome was evaluated 4 weeks after attaining these blood levels. Twenty-two patients had a positive response to the DT, whereas 108 patients had a negative response. Although a positive DT is correlated with a high level of trait anxiety, no differences in depressive symptomatology and antidepressant response were found between patients with a positive and a negative DT.

A rapid LC coupled with electrospray ionization (ESI) MS/MS method was developed and validated for the quantification of paroxetine in heparinized human plasma. The plasma samples were prepared by the solid-phase extraction method without drying or reconstitution. Elution was done with 0.5 mL 0.2% (v/v) formic acid in methanol-acetonitrile (65 + 35, v/v). The analyte and the internal standard (IS; imipramine hydrochloride) were chromatographed on a BDS Hypersil C18 column. The analyte was analyzed by LC/MS/MS with only 1.7 min run time. An ESI interface was chosen for ionization of the analyte from the sample matrix. Selected reaction monitoring mode for detection of paroxetine and the IS were achieved by using m/z 330.17/192.10 and 281.13/86.14, respectively. The LC retention times for paroxetine and imipramine were 0.94 and 1.05 min, respectively. The method was linear in the concentration range of 0.5-80.0 ng/mL with r > or = 0.9995. Recovery of paroxetine and imipramine ranged from 90 to 95%. The assay has been successfully applied to bioequivalence study samples for estimation of paroxetine in healthy human subjects.

Binding by the drug imipramine to the protein human serum albumin (HSA) was studied by using high-performance affinity chromatography. The association equilibrium constants and number of binding sites for imipramine with HSA were first estimated by utilizing frontal analysis. Imipramine was found to have one major binding site on HSA with an association equilibrium constant of 1.6 x 10(5) M(-1) at pH 7.4 and 37 degrees C, as well as a second group of weaker and non-specific binding regions (8-9 mol/mol HSA) with an average association equilibrium constant of 1.5 x 10(3) M(-1). Competition studies based on zonal elution were performed to identify the location of the major binding site for imipramine on HSA. Imipramine was found to have direct competition with L-tryptophan, which indicated that imipramine was interacting with Sudlow site II, or the indole-benzodiazepine site of HSA. No competition or allosteric effects were noted between imipramine and warfarin, a probe for Sudlow site I or the warfarin-azapropazone site of HSA. The association equilibrium constant found for imipramine at its site of competition with L-tryptophan also agreed with the value that was obtained for the major binding site of imipramine in the frontal analysis studies. These results confirmed that Sudlow site II was the location of the major binding site for imipramine on HSA. These results gave good agreement with previous observations made in the literature and should provide a more detailed description of how imipramine is transported in blood and of how it may interact with other drugs in the body.

Introduction: Verapamil is a calcium channel blocker that also inhibits the P-glycoprotein (Pgp) membrane transporter. We have found that administration of verapamil with a recognised antidepressant improves clinical outcome in previously treatment resistant cases despite the fact that verapamil does not possess inherent antidepressant activity. In this study we examined the hypothesis that the antidepressant-like effects of verapamil are mediated through its blockade of the Pgp transporter in the blood brain barrier (BBB)., Methods: Following pre-treatment with verapamil (20 mg/kg) or a saline solution male Sprague Dawley rats were injected with imipramine (15 mg/kg). Two hours later, the animals were sacrificed, trunk blood collected and brain regions dissected out. High performance liquid chromatography (HPLC) was used to quantitate antidepressant drug concentrations in all samples., Results: Verapamil pre-treatment significantly elevated imipramine concentrations in all brain regions studied. The effect was most pronounced in the brainstem and frontal cortex where we observed in excess of a doubling in the brain region: serum ratios., Conclusion: Our results verify inhibition of Pgp as a potential mechanism of action for verapamil during treatment resistant depression. The implications of these findings are discussed in the context of novel treatment strategies in depression.

The inactivation and clearance of the tricyclic antidepressant imipramine is dependent on CYP2D6 activity. First, CYP2C19 converts imipramine into the active metabolite desipramine, which is then inactivated by CYP2D6. This retrospective single center study aimed to prove whether CYP2C19 and ample CYP2D6 genotyping (taking into consideration four null alleles and three decreased-activity alleles) could be used to predict imipramine and desipramine plasma concentrations in depressed patients, and whether genotype-based drug dose recommendations might assist in the early management of imipramine pharmacotherapy. In 181 subjects with major depressive disorder, drug doses were recorded, imipramine and desipramine plasma concentrations were monitored and CYP2C19 (*2) and CYP2D6 genotype (*3, *4, *5, *6, *9, *10, *41 and gene duplication) were obtained, yielding graded allele-specific CYP2D6 patient groups. Desipramine and imipramine+desipramine plasma concentration per drug dose unit, imipramine dose at steady state, and imipramine dose requirement significantly depended on CYP2D6 genotype (Kruskal-Wallis test, P<0.0001). Mean (+/-s.d.) drug dose requirements were 131 (+/-109), 155 (+/-70), 217 (+/-95), 245 (+/-125), 326 (+/-213), and 509 (+/-292) mg imipramine/day in carriers of 0, 0.5, 1, 1.5, 2, and >2 active CYP2D6 genes, respectively. Our protocol for CYP2D6 genotyping will thus importantly aid in the prediction of imipramine metabolism, allowing for the use of an adjusted starting dose and faster achievement of predefined imipramine+desipramine plasma levels in all genetic patient subgroups. Therefore, therapeutic efficacy and efficiency may be improved, the number of adverse drug reactions decreased, and hospital stay reduced.

The paper describes the effect of amantadine addition to imipramine therapy in patients suffering from treatment-resistant unipolar depression who fulfilled DSM IV criteria for major (unipolar) depression. Fifty patients were enrolled in the study on the basis of their histories of illness and therapy. After a 2-week drug-free period, 25 subjects belonging to the first group were treated only with imipramine twice daily (100 mg/day) for 12 weeks, and 25 subjects belonging to the second group were treated with imipramine twice daily (100 mg/day) for 6 weeks and then amantadine was introduced (150 mg/day, twice daily) and administered jointly with imipramine for the successive 6 weeks. Hamilton Depression Rating Scale (HDRS) was used to assess the efficacy of antidepressant therapy. Imipramine did not change the HDRS score after 3, 6 or 12 weeks of treatment when compared with the washout (before treatment). The addition of amantadine to the classic antidepressant reduced HDRS scores after 6-week joint treatment. Moreover, the obtained pharmacokinetic data indicated that amantadine did not significantly influence the plasma concentration of imipramine and its metabolite desipramine in patients treated jointly with imipramine and amantadine, which suggests lack of a pharmacokinetic interaction. The obtained results indicate that joint therapy with an antidepressant and amantadine may be effective in treatment-resistant unipolar depression.

Solid-phase microextraction coupled to liquid chromatography and mass spectrometry (SPME-LC-MS) was used to analyze tricyclic antidepressant drugs desipramine, imipramine, nortriptyline, amitriptyline, and clomipramine (internal standard) in plasma samples. SPME was performed by direct extraction on a PDMS/DVB (60 microm) coated fiber, employing a stirring rate of 1200 rpm for 30 min, pH 11.0, and temperature of 30 degrees C. Drug desorption was carried out by exposing the fiber to the liquid chromatography mobile phase for 20 min, using a labmade SPME-LC interface at 50 degrees C. The main variables experimentally influencing LC-MS response were evaluated and mathematically modeled. A rational optimization with fewer experiments was achieved using a factorial design approach. The constructed empirical models were adjusted with 96-98% of explained deviation allowing an adequate data set comprehension. The chromatographic separation was realized using an RP-18 column (150 mm x 2.1 mm, 5 microm particles) and ammonium acetate buffer (0.01 mol/l, pH 5.50) : acetonitrile (50 : 50 v/v) as mobile phase. Low detection levels were achieved with electrospray interface (0.1 ng/ml). The developed method showed specificity, linearity, precision, and limit of quantification adequate to assay tricyclic antidepressant drugs in plasma.

Singlet oxygen generated in a reaction between N-bromosuccinimide and hydrogen peroxide was used for the chemiluminescence oxidation of imipramine. A strong chemiluminescence signal was observed when imipramine was mixed with N-bromosuccinimide and hydrogen peroxide under an alkaline condition. The chemiluminescence signal was linearly dependent on the concentration of imipramine in the range of 0.01 - 1.0 mg/L. The detection limit was 0.005 mg/L imipramine and the relative standard deviation was 1.5% for a 0.4 mg/L imipramine solution in 11 repeated measurements. The proposed method was successfully applied to the determination of imipramine in tablets, human plasma and urine samples.

Objective: Up to 15% of depression patients eventually present with treatment-resistant or refractory depression (TRD), a condition that causes significant social and economic burdens. Our paper aims to summarize the current medical literature on the conceptual and methodologic issues involved in the definition, assessment, and staging of TRD., Method: We reviewed the recently published medical literature to identify papers that specifically discuss TRD. For this, we searched MEDLINE, EMBASE, and PsycINFO for potentially relevant English-language articles published between January 1996 and June 2006., Results: Recent methodologic and conceptual advances have contributed to the achievement of an acceptable level of theoretical consensus on the general meaning of TRD. Accordingly, depression is usually considered resistant or refractory when at least 2 trials with antidepressants from different pharmacologic classes (adequate in terms of dosage, duration, and compliance) fail to produce a significant clinical improvement. Regarding diagnostic assessments, an accurate and systematic evaluation should be made to elicit the potential role of several contributing factors, such as medical and psychiatric comorbidity., Conclusion: Recently, 3 staging methods for TRD have been described, but they currently require extensive empirical support. Future research on TRD should include prospective studies addressing the validity of the proposed criteria, the impact of depression comorbid with other psychiatric disorders and (or) physical conditions, and the possible predictors o treatment outcome. There is an important and clear need for studies that empirically test current definitions, assessment strategies, and staging methods of TRD.

Simple, sensitive, and reproducible off-line solid-phase microextraction and liquid chromatography (SPME/LC) methods are described for the determination of seven anticonvulsants and tricyclic antidepressants in human plasma. Factorial design and simplex methodology were applied in the optimization of the SPME procedure for tricyclic antidepressants analyses. Important factors in the SPME efficiency are discussed, such as the fiber coatings (both lab-made and commercial), extraction time, pH, ionic strength, influence of plasma proteins, and desorption conditions. The development of the lab-made fiber coatings, namely, octadecylsilane, aminosilane, and polyurethane, are further described and applied to anticonvulsants analyses. The investigated plasmatic range for the evaluated anticonvulsants, using CW-TPR fiber, were the following: phenylethylmalonamide (3.00-40.0 microg mL(-1)), phenobarbital (5.00-40.0 microg mL(-1)), primidone (3.00-40.0 microg mL(-1)), carbamazepine and carbamazepine-epoxide (2.00-24.0 microg mL(-1)), phenytoin (2.00-40.0 microg mL(-1)), and lamotrigine (0.50-12.0 microg mL(-1)). The antidepressants' linear plasmatic concentration ranged from 75.0 to 500 ng mL(-1) for imipramine, amitriptyline, and desipramine, and from 50.0 to 500 ng mL(-1) for nortriptyline, being in all cases, the limit of quantification represented by the lowest value. The precision (interassays) for all investigated drugs in plasma sample spiked with different concentrations of each analyte and submitted to the described procedures were lower than 15%. The off-line SPME/LC methodologies developed allow anticonvulsants and antidepressants analyses from therapeutic to toxic levels for therapeutic drug monitoring.

We present a fatal imipramine poisoning. Quantitative analysis of imipramine and its metabolite, desipramine, was performed by high-performance liquid chromatography. The concentrations of imipramine and desipramine were 18.67 microg/mL and 6.21 microg/mL in heart blood and 6.90 microg/mL and 1.77 microg/mL in the femoral venous blood, respectively. We concluded that the cause of death was due to imipramine poisoning.

The effect of aging on steady-state plasma concentrations of citalopram (CIT) and desmethylcitalopram (DCIT) was investigated in 128 depressive patients treated with 10-80 mg/day CIT. They were separated into three groups, with age up to 64 years (mean age+/-S.D.: 47+/-12 years; n=48), between 65 and 79 years (72+/-1 years; n=57), and from 80 years or older (84+/-1 years; n=23). Body mass index (BMI), renal and hepatic functions were similar in the three groups. A large interindividual variability of plasma levels of CIT (16-fold) and DCIT (12-fold) was measured for a given dose. The mean plasma levels of CIT corrected for a 20 mg daily dose were 55% higher in the very elderly (>=80 years) patients (65+/-30 ng/ml; p<0.001) and 38% higher in the elderly (65-79 years) patients (58+/-24 ng/ml; p<0.001) when compared to the adult patients (42+/-17 ng/ml). DCIT mean plasma level was 38% higher (p<0.05) in the group of very elderly patients (22+/-10 ng/ml) when compared to the adult patients (16+/-9 ng/ml). As a consequence, the mean plasma concentration of CIT+DCIT was 48% higher in the very elderly patients (86+/-36 ng/ml; p<0.001) and 33% higher in the elderly patients (77+/-28 ng/ml; p<0.001) when compared to the adult patients (58+/-21 ng/ml). Age correlated significantly with CIT (r=0.43, p<0.001), DCIT (r=0.28, p<0.01), and CIT+DCIT plasma levels (r=0.44, p<0.001), and thus accounts for 18% of the variability of CIT plasma levels, with no influence of gender. The recommended dose reduction of CIT in elderly patients seems therefore justified.

The effect of joint administration of imipramine (IMI) and magnesium (Mg) on antidepressant-like activity was studied in mice using forced swim test (FST). Mg doses ineffective per se (5 and 10 mg/kg) given jointly with IMI also at ineffective doses (10 and 15 mg/kg) resulted in a potent reduction in the immobility time. Since these combined treatments did not influence locomotor activity, the antidepressant-like activity was not due to non-specific behavioral activation. Moreover, we estimated the effect of joint administration of magnesium and IMI in FST on serum and brain magnesium, IMI and its active metabolite desipramine (DMI) concentrations in mice. Swim stress (mice subjected to FST) increased the magnesium concentration in serum and decreased it in the brain compared to naive animals. Moreover administration of IMI increased (normalized) magnesium brain concentration, without influence on the serum level. Joint administration of IMI and magnesium did not influence magnesium (compared with FST) or IMI and DMI (compared with IMI treatment alone) concentrations in both examined tissues. The present data demonstrated an enhancement of the antidepressant-like effect by joint administration of IMI and magnesium in the FST, and further indicate the particular role of magnesium in the antidepressant action. Since there was no increase in IMI, DMI or magnesium concentration after joint administration of magnesium and IMI, the data suggest that pharmacodynamic rather than pharmacokinetic interaction between magnesium and IMI is accountable for behavioral effect in the FST.

A micellar liquid chromatographic (MLC) procedure was developed for the clinical monitoring of imipramine and its active metabolite, desipramine. The determination of these highly hydrophobic substances was carried out after direct injection of the serum samples using a mobile phase composed of 0.15 m SDS--6% (v/v) pentanol buffered at pH 7, pumped at 1.5 mL/min into a C(18) column (250 x 4.6 mm), and electrochemical detection at 650 mV. Using this MLC method, calibration was linear (r > 0.995) and the limits of detection (ng/mL) were 0.34 and 0.24 for imipramine and desipramine, respectively. Repeatabilities and intermediate precision were tested at three different concentrations in the calibration range and a CV (%) below 2.2 was obtained. In this MLC procedure, the serum is determined without treatment, thus allowing repeated serial injections without changes in retention factors, and reducing the time and consumables required to carry out the pretreatment process. The assay method can be applied to the routine determination of serum imipramine and its metabolite in therapeutic drug monitoring., ((c) 2004 John Wiley & Sons, Ltd.)

The in vitro permeation studies of imipramine hydrochloride (IMH) reported earlier from our laboratory showed that a combination of menthol (2.5% w/v) and oleic acid (2.5% w/v) worked well in terms of safety and efficacy. The main objective of this study was to evaluate the in vivo performance of this combination; in order to do that, penetration enhancers were incorporated in a hydro-alcoholic gel of hydroxypropylmethyl cellulose along with IMH and used as the drug matrix in a reservoir transdermal patch. A stability study of IMH gel was performed at 40 degrees C/75% RH for 2 months. The results of this study indicate that gels of IMH stored at 40 degrees C/75% RH turned yellow brown in 2 months and the small change in viscosity of gel at 40 degrees C/75% RH had an insignificant effect on the release rate of IMH from the gel (p>0.05). The in vivo performance of the gel was tested in rats using a reservoir transdermal patch, which consisted of a backing membrane, drug matrix and retaining membrane with an area of 12.5 cm2. Plasma concentrations of 3 microg/ml of IMH were achieved and in a histopathological study 24 h occlusion was found to be safe., (Copyright 2004 John Wiley & Sons, Ltd.)

Objective: To compare the efficacy of imipramine and fluvoxamine in inpatients from two centers suffering from a depressive disorder according to DSM IV criteria., Methods: The study included 141 patients with a depressive disorder according to DSM IV criteria. After a drug-free and placebo run-in period of 1 week, patients were randomized to imipramine or fluvoxamine; doses of both drugs were adjusted to a predefined target blood level. Efficacy was evaluated 4 weeks after attaining predefined adequate plasma level., Results: The mean age of the study group (47 males, 94 females) was 51.8 (range 19-65) years. Of these 141 patients, 56 had episode duration longer than 1 year, 48 had mood congruent psychotic features, and 138 patients received medication. Seven patients did not complete the medication trial. The total number of patients using concurrent medication was 12/138 (8.6%). On the primary outcome criteria patients on imipramine improved significantly better on the change of illness severity score of the CGI (chi2 exact trend test=4.089, df=1, P=-0.048). There was no significant difference in 50% or more reduction on the HRSD, the other primary outcome criterion. On the secondary outcome criteria the mean reduction of the HRSD scores was significantly larger in the imipramine group than in the fluvoxamine group (mean difference=3.1, standard error (SE)=1.4, t=2.15, df=136, P=0.033). There was no significant difference in the number of patients with an HRSD < or =7 at the final evaluation., Conclusions: In depressed inpatients imipramine is more efficacious than fluvoxamine. Both drugs were well tolerated by all patients.

Tricyclic antidepressants (TCA) are the best-documented treatment of neuropathic pain. TCAs have a pronounced interindividual pharmacokinetic variability and a narrow therapeutic index. The aim of this study was to characterize the plasma concentration-effect relationship of imipramine in neuropathic pain and to determine the usefulness of therapeutic drug monitoring (TDM) of TCA treatment in a population with noncancer chronic pain. To do this, 83 patients with chronic noncancer neuropathic pain were included. Information on previous use of TCA was collected, and patients were tested for the presence of hyperalgesia. Pain intensity and pain relief were recorded, and the Short Form McGill Pain Questionnaire and Major Depression Inventory were completed before and during a TDM-based imipramine treatment. Imipramine dose was increased in steps of 25 mg/d every second week, and blood samples were taken at every dose. Endpoints were best possible pain relief, unacceptable side effects, or insufficient pain relief despite plasma drug level > 500 nmol/L. Dose range used was 10-300 mg/d. The study showed that imipramine 75 mg/d caused a 36-fold interindividual variation in steady-state plasma drug concentrations. In 46 responders (global pain relief > 25%) the plasma drug concentration at which an individual maximal analgesic effect was obtained ranged from 50 to 1400 nmol/L, but for the majority it was below 400 nmol/L. The concentration-effect relationship was similar for patients with central versus peripheral neuropathic pain and independent of the presence of hyperalgesia. Previous treatment failure with non-TDM TCA treatment was not a predictor of poor response to TDM-based treatment. In conclusion, there is a pronounced interindividual variability in concentration-effect relationship for imipramine treatment in neuropathic pain, but the majority of patients obtain a maximal analgesic effect at drug levels below 400 nmol/L. The concentration-effect relationship is similar for patients with central and peripheral neuropathic pain. Further studies are needed to document if TDM improves pain relief; however, TDM reduces the risk for toxicity.

Treatment outcome in patients with neuropathic pain (NP) is often variable and disappointing. We tested the hypothesis that patients with clear evidence of nervous system lesion respond better to pharmacological treatment with documented effect on NP than patients with poor or no evidence of nervous system lesion. Furthermore, we examined whether specific symptoms or signs were associated with treatment outcome. A total of 214 patients with suspected non-cancer NP were divided into four groups with graded evidence of nervous system lesion based on medical history, bedside sensory examination, quantitative sensory tests, electrophysiology, and neuroimaging. Patients were treated with imipramine guided by plasma-drug concentrations. Gabapentin 2400 mg/day was given in case of treatment failure or if imipramine treatment was not possible. Two hundred patients completed the study. Global pain relief was similar in the four groups. There was no association between evidence of nervous system lesion and treatment outcome. Classical NP signs: abnormal temporal summation, cold and brush allodynia, and abnormal sensibility to temperature were also unrelated to outcome. Treatment outcome was similar in peripheral and central definite NP. Neither definite evidence of nervous system lesion nor abnormal sensory phenomena seems to predict for good outcome of therapy with imipramine or gabapentin in patients with suspected neuropathic pain.

1. Animal experiments have shown nitric oxide synthase inhibitors to have antidepressant-like properties. However, the effects of clinically available antidepressants on nitric oxide production in the brain remain unclear. In the present study, we examined whether imipramine, a conventional antidepressant, changes the levels of type-II nitric oxide synthase mRNA and nitrate, a final nitric-oxide-oxidation product measurable in vivo, in the rat brain. 2. Type-II nitric oxide synthase mRNA was detected using a reverse transcription-polymerase chain reaction method and nitrate was measured with a combination of high-performance liquid chromatography and the Griess reaction. 3. In untreated rats, type-II nitric oxide synthase mRNA was not detected in the hypothalamus, hippocampus, cerebral cortex, brain stem, or cerebellum. However, after 28-day oral administration of imipramine, it was detected in every brain region tested. Nitrate levels in the hypothalamus and cerebral cortex increased after 28-day treatment. In the hypothalamus, nitrate levels increased dose-dependently. These dose-dependent nitrate level changes were prevented by pretreatment with a nitric oxide synthase inhibitor. Moreover, the preventive effect of NG-nitro-L-arginine methyl ester was reversed by coadministration of L-arginine, a nitric oxide substrate. 4. These results suggest that chronic imipramine treatment induces nitric oxide synthase gene expression in the brain, followed by augmented NO production.

In the present study, we examined the effects of imipramine (IMI) and metyrapone (MET) given alone or in combination of IMI and MET in the forced swimming test in rats. We also measured pharmacokinetic parameters: the level of IMI and its metabolite, desipramine (DMI), in the rat plasma and brain (1 h after the forced swimming test). The present studies indicate that MET (50 mg/kg) reduced immobility time. Combined treatment with MET (50 mg/kg) and IMI (5 or 10 mg/kg) produced stronger antidepressant-like effect than either of drugs given alone. Sulpiride (dopamine D2/3 antagonist), or WAY 100635 (5-HT1A antagonist) but not prazosin, (alpha1-adrenergic antagonist), at doses ineffective in the forced swimming test, inhibited an antidepressant-like effect induced by co-administration of IMI with MET. The active behaviors in that test did not reflect an increase in general activity, since combined administration of IMI and MET failed to alter the locomotor activity of rats, measured in the open field test. MET elevated the concentrations of IMI and DMI in plasma, and the total drug concentration (IMI + DMI) was doubled by MET. In the brain, MET enhanced the concentration of IMI, but decreased that of DMI, consequently, the brain IMI/DMI ratio increased twice. The total drug concentration in the brain (IMI + DMI) was not changed significantly by MET treatment. The obtained results suggest that dopamine D2/3 and 5-HT1A receptors may contribute to the mechanism of synergistic action of IMI and MET in the forced swimming test in rats, and that pharmacokinetic interaction should not have a substantial impact on the MET-induced potentiation of IMI effect, observed in vivo. These findings may be of particular importance to pharmacotherapy of drug-resistant depression.

Unlabelled: 34 patients with diagnosis of depressive episode (ICD-10) were treated for 8 weeks with tricyclic antidepressants (TCA) 22 patients were treated with clomipramine 75-175 mg daily, 11 with imipramine 75-150 mg and 1 with amitriptyline 150 mg. Following parameters were analysed: plasma concentration (FPIA, HPLC), pharmaco-EEG (spectrum power for delta, theta, alfa1, 2, beta 1, 2, 3 by the use of FFT), clinical improvement (HAMD, HARS, SGI, SERS). 50% reduction in HAMD was regarded as improvement., Results: No relationship between mental state and plasma concentration of TCA was found, initial results in SERS were prognostic for the course of treatment, pharmaco-EEG was typical for antidepressants after two weeks of treatment and reflects clinical improvement and stabilization of plasma concentration. Comparing the plasma concentration of TCA measured by the use of FPIA and HPLC method may be useful for the implementation of monitoring therapy.

Background: The circadian variations of the serotonin reuptake sites were studied in 16 patients meeting DSM-IV criteria for major depression with melancholia, either with (n=8) or without (n=8) psychotic symptomatology., Method: The [3H]imipramine binding sites were measured in platelet samples., Results: While no statistically significant difference was found between the morning (09:00 h) and evening (21:00 h) [3H]imipramine B(max) values in the control group, both the non-delusional and delusional melancholic patients showed higher evening than morning B(max) values, which were only statistically significant in the former. When both diagnostic groups were compared, the delusional patients showed significantly lower [3H]imipramine binding values than the non-delusional patients both in the morning and evening samples. Within the non-delusional depressed patients, those individuals with mood circadian variation, assessed by the 18th item of the HDRS, showed significantly lower B(max) values than those without mood variation. Lowest morning and evening B(max) values were noted in the delusional depressed group without mood variations., Conclusions: These results suggest that delusional depressions might have a different neurobiological substrate with loss of chronobiological rhythms.

Triiodothyronine (T3) has been shown to accelerate and potentiate the clinical response to tricyclic antidepressant (TCA) treatment in depressive disorders. The neurobiological mechanisms underlying these therapeutic effects of T3 are still unknown. Since brain serotonin (5-HT) changes have been implicated in the mode of action of TCA drugs, the effects of a chronic (7 or 21 days) administration of imipramine (10 mg/kg/day) and of a low dose of T3 (4 microg/kg/day), given alone or in combination, were investigated on the density of midbrain 5-HT transporters and of hippocampal 5-HT(1A) and cortical 5-HT(2A) receptors in adult Wistar rats. Neither single nor combined administration of imipramine and T3 for 7 days modified the density of 5-HT transporters and of 5-HT(1A) receptors. On day 21, the combination did not change imipramine- or T3-induced decrease in 5-HT transporter density whereas it prevented imipramine-induced increase in 5-HT(1A) receptor density. Whatever the treatment duration, imipramine-T3 combination potentiated imipramine-induced decrease in 5-HT(2A) receptor density. On both day 7 and day 21, T3 given alone had no effects on the density of 5-HT(1A) and 5-HT(2A) receptors. These data indicate that T3 is able to modulate the long-term adaptive changes which occur at the postsynaptic level of 5-HT neurotransmission after antidepressant treatment.

Objective: To validate use of high-performance liquid chromatography (HPLC) in determining imipramine concentrations in equine serum and to determine pharmacokinetics of imipramine in narcoleptic horses., Animals: 5 horses with adult-onset narcolepsy., Procedure: Blood samples were collected before (time 0) and 3, 5, 10, 15, 20, 30, and 45 minutes and 1, 2, 3, 4, 6, 8, 12, and 24 hours after IV administration of imipramine hydrochloride (2 or 4 mg/kg of body weight). Serum was analyzed, using HPLC, to determine imipramine concentration. The serum concentration-versus-time curve for each horse was analyzed separately to estimate pharmacokinetic values., Results: Adverse effects (muscle fasciculations, tachycardia, hyperresponsiveness to sound, and hemolysis) were detected in most horses when serum imipramine concentrations were high, and these effects were most severe in horses receiving 4 mg of imipramine/kg. Residual adverse effects were not apparent. Value (mean +/- SD) for area under the curve was 3.9 +/- 0.7 h X microg/ml, whereas volume of distribution was 584 +/- 161.7 ml/kg, total body clearance was 522 +/- 102 ml/kg/h, and mean residence time was 1.8 +/- 0.6 hours. One horse had signs of narcolepsy 6 and 12 hours after imipramine administration; corrresponding serum imipramine concentrations were less than the therapeutic range., Conclusions and Clinical Relevance: Potentially serious adverse effects may be seen in horses administered doses of imipramine that exceed a dosage of 2 mg/kg. Total body clearance of imipramine in horses is slower than that in humans; thus, the interval between subsequent doses should be longer in horses.

The hypoalgesic effect of single oral doses of 100 mg imipramine and 125 mg codeine was evaluated in a randomised, placebo-controlled, double-blind, 3-way cross-over experiment including 18 healthy volunteers. Pain tests were performed before and 90, 180, 270, 360 and 450 min after medication. The tests included determination of pain tolerance thresholds to pressure, pain detection/tolerance thresholds to single electrical sural nerve stimulation and pain summation at tolerance threshold to repetitive electrical sural nerve stimulation (temporal summation) and pain experienced during the cold pressor test, rated as peak pain intensity, pain average intensity and discomfort. Compared to placebo, imipramine significantly increased pressure pain tolerance threshold (P = 0.03) and increased pain tolerance threshold (P = 0.05) and pain summation threshold (P = 0.03), but not pain detection threshold to electrical stimulation. Imipramine did not cause significant changes in pain perception during the cold pressor test. Codeine significantly increased pressure pain tolerance threshold (P = 0.02), pain detection (P = 0.04) and pain tolerance threshold (P = 0.01) and pain summation threshold (P = 0.02) to electrical stimulation. In addition, codeine reduced the pain experienced during the cold pressor test (P = 0.04-0.003). It is concluded that both imipramine and codeine inhibit temporal pain summation, whereas only codeine reduces cold pressor pain. Pain summation may be a key mechanism in neuropathic pain. Imipramine has a documented effect on such pain conditions on temporal summation. The present study showed that codeine also inhibits temporal summation, which is in line with the clinical observations indicating that opioids relieve neuropathic pain.

Objective: To evaluate the effects of continuous hormone replacement therapy (HRT) regimens on platelet-tritiated ((3)H-) imipramine binding (Bmax) and mood., Design: Prospective randomized study., Setting: University hospital., Patient(s): Sixty postmenopausal patients., Intervention(s): Randomization to 3 months of daily treatment with tibolone and conjugated equine estrogen (CEE).625 mg combined either with 2.5 or 5 mg of medroxyprogesterone acetate (MPA). The inclusion criteria-matched patients declined for HRT were prescribed daily alendronate. Pre- and posttreatment blood sampling for Bmax and mood evaluation with the Beck Depression Inventory (BDI) and the State-Trait Anxiety Inventory (STAI) were done., Main Outcome Measure(s): Pre- and posttreatment Bmax and mood scores., Result(s): As compared with baseline, both CEE+MPA regimens and tibolone significantly increased Bmax. The comparisons of percent change from baseline Bmax for the CEE+MPA and tibolone groups were similar. All three HRT regimens improved the BDI significantly, while there were no significant changes in the STAI. In the alendronate group, there were no significant changes in both pre- and posttreatment Bmax and mood scores., Conclusion(s): Continuous treatment with CEE+MPA and tibolone increases platelet (3)H-imipramine binding and improves mood. Mood-enhancing effects of tibolone may occur through the serotonergic system, as is the case with estrogen.

A chip-based capillary electrophoresis/mass spectrometry (CE/MS) system is described for the on-chip separation and coupled electrospray detection of selected small drug molecule compounds. These studies include the quantitative determination of carnitine and acetylcarnitine in analytical standard solutions as well as imipramine and desipramine in fortified human plasma samples. A clinical human plasma sample was also analyzed following the normal administration of desipramine to a volunteer, and the parent drug was determined using the described chipbased CE/MS technique. In each instance, stable isotope-incorporated internal standards were used. The chip-based CE system was microfabricated from glass and coupled to a micro ion spray device constructed in-house. The atmospheric pressure ionization system employed in this work was a PE Sciex API III tandem triple quadrupole system operated in the selected ion monitoring (SIM) mode. The results from the work reported here demonstrate the feasibility for carrying out rapid (30 s) chipbased quantitative CE/MS determinations of samples containing small-molecule compounds. Using SIM CE/ MS techniques, the described API III quadrupole system provided acceptable ion current electropherograms from subpicomole levels of the targeted compounds loaded onto the chip. The corresponding electropherograms for the standard solution of carnitines at the 1-500 microg/mL level were obtained via SIM CE/MS techniques (R2 > 0.99). In addition, analyses of fortified samples of imipramine desipramine were measured relative to their corresponding d3 internal standards to obtain calibration curves ranging from 5 to 500 microg/mL in human plasma (R2 > 0.99). The intra-assay precision ranged from 4.1 to 7.3% RSD. The intra-assay accuracy ranged from 94.0 to 104%. These results demonstrate the feasibility for on-chip CE separation and electrospray mass spectrometric determination in applications for bioanalytical measurements for these important compounds in synthetic mixtures and human plasma extracts.