Uptake and metabolism of the antidepressants sertraline, clomipramine, and trazodone in a garden cress (Lepidium sativum) model

Environmental contamination with pharmaceuticals has received growing attention in recent years. Several studies describe the presence of traces of drugs in water bodies and soils and their impacts on nontarget organisms including plants. Due to these facts investigations of the uptake and metabolism of pharmaceuticals in organisms is an emerging research area. The present study demonstrates the analysis of three selected antidepressants (sertraline, clomipramine, and trazodone) as well as metabolites and transformation products in a cress model (Lepidium sativum). Cress was treated with tap water containing 10 mg/L of the parent drugs. Employing an analytical approach based on high performance liquid chromatography coupled with quadrupole time of flight or Orbitrap mass spectrometry in MS and MS² modes, in total 14 substances were identified in the cress extracts. All three parent drugs were taken up by the cress and translocated from the roots to the leaves in specific patterns. In addition to this, eleven metabolite species were identified. They were generated by hydroxylation, demethylation, conjugation with amino acids, or combinations of these mechanisms. Finally, the inclusion of control cultures in the experimental setup allowed for a differentiation of "true" metabolites generated by the cress and transformation products generated by plant-independent mechanisms.

Correlation of plasma and peritoneal diasylate clomipramine concentration with hemodynamic recovery after intralipid infusion in rabbits

OBJECTIVES

Drug sequestration to an expanded plasma lipid phase has been proposed as a potential mechanism of action for lipid emulsions in lipophilic cardiotoxin overdose. The authors set out to document plasma and peritoneal diasylate clomipramine concentration after resuscitation with lipid emulsion in a rabbit model of clomipramine-induced hypotension.

METHODS

Twenty sedated mechanically ventilated New Zealand White rabbits were allocated to receive either 12 mL/kg 20% Intralipid or 12 mL/kg saline solution, following clomipramine infusion to 50% baseline mean arterial pressure (MAP). Hemodynamic parameters and serum clomipramine concentration were determined to 59 minutes. Peritoneal dialysis with 20% Intralipid or saline solution was evaluated for clomipramine concentration.

RESULTS

Mean arterial pressure was greater in lipid-treated animals as assessed by repeated-measures analysis of variance (F[1,14] = 6.84; p = 0.020). Lipid infusion was associated with elevated plasma clomipramine concentration and reduced initial volume of distribution (Vd; 5.7 [+/-1.6] L/kg lipid vs. 15.9 [+/-7.2] L/kg saline; p = 0.0001). Peritoneal diasylate clomipramine concentration was greater in lipid-treated animals (366.2 [+/-186.2] microg/L lipid vs. 37.7 [+/-13.8] microg/L saline; p = 0.002).

CONCLUSIONS

Amelioration of clomipramine-induced hypotension with lipid infusion is associated with reduced initial Vd and elevated plasma clomipramine concentration consistent with intravascular drug-lipid sequestration. Concomitant peritoneal dialysis with lipid emulsion enhances clomipramine extraction.

Forensic toxicological implication of an autopsy case of mixed drug overdose involving clomipramine, chlorpromazine and flunitrazepam

A case of fatal poisoning involving clomipramine, chlorpromazine and flunitrazepam is presented. Quantitative toxicological analysis showed that the concentrations of clomipramine, chlorpromazine and 7-aminoflunitrazepam (a metabolite of flunitrazepam) in the femoral blood were 3.24 microg/ml, 0.36 Kg/ml and 0.61 microg/ml, respectively, and large amounts of drugs were also detected from the stomach contents. We concluded that the cause of death was due to the combined use of clomipramine, chlorpromazine and flunitrazepam.

Development of an HPLC method for the monitoring of tricyclic antidepressants in biofluids

A simple, rapid and sensitive HPLC method was developed and validated for the determination of four tricyclic antidepressants (TCAs): amitriptyline, doxepin, clomipramine (CLO) and imipramine, in pharmaceutical formulations and biological fluids. A Kromasil C(8 )analytical column (250 x 4 mm, 5 microm) was used for the separation, with a mobile phase consisting of 0.05 M CH(3)COONH(4) and CH(3)CN (45:55 v/v) delivered at 1.5 mL/min isocratically. Quantification was performed at 238 nm, with bromazepam (1.5 ng/microL) as the internal standard. The determination of TCAs in blood plasma was performed after protein precipitation. Urine analysis was performed by means of SPE using Lichrolut RP-18 Merck cartridges providing high absolute recoveries (> 94%). Direct analysis of urine was also performed after two-fold dilution. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity. Repeatability (n = 5) and between-day precision (n = 5) revealed RSD <13%. Recoveries from biological samples ranged from 91.0 to 114.0%. The absolute detection limit of the method was calculated as 0.1-0.6 ng in blood plasma and 0.2-0.5 ng in extracted urine or 0.4-0.7 in diluted urine. The method was applied to real samples of plasma from a patient under CLO treatment.

Supported liquid membranes in hollow fiber liquid-phase microextraction (LPME) – Practical considerations in the three-phase mode

In this work, three-phase liquid-phase microextraction (LPME) based on a supported liquid membrane (SLM) sustained in the wall of a hollow fiber was investigated with special focus on optimization of the experimental procedures in terms of recovery and repeatability. Recovery data for doxepin, amitriptyline, clomipramine, and mianserin were in the range of 67.8-79.8%. Within-day repeatability data for the four basic drugs were in the range of 4.1-7.7%. No single factor was found to be responsible for these variations, and the variability was caused by several factors related to the LPME extractions as well as to the final HPLC determination. Although the volume of the SLM varied within 0.4-3.1% RSD depending on the preparation procedure, and the volume of the acceptor solution varied within 4.8% RSD, both recoveries and repeatability were found to be relative insensitive to these variations. Thus, the handling of microliters of liquid in LPME was not a very critical factor, and the preparation of the SLM was accomplished in several different ways with comparable performance. Reuse of hollow fibers was found to suffer from matrix effects due to built-up of analytes in the SLM, whereas washing of the hollow fibers in acetone was beneficial in terms of recovery, especially for the extraction of the most hydrophobic substances. Several of the organic solvents used in the literature as SLM suffered from poor long-term stability, but silicone oil AR 20 (polyphenylmethylsiloxane), 2-nitrophenyl octyl ether (NPOE), and dodecyl acetate (DDA) all extracted with unaltered performance even after 60 days of storage at room temperature.

Determination of fluoxetine, fluvoxamine, and clomipramine in pharmaceutical formulations by capillary gas chromatography

A simple and fast capillary gas chromatographic method with flame ionization detection is proposed for the simultaneous determination of fluoxetine, fluvoxamine, and clomipramine without a prederivatization. The reported method is the first one that allows the determination of three selective serotonin reuptake inhibitors. Optimal conditions for the quantitative separation were investigated: column head pressure (80 kPa), injector and detector temperatures (260 and 250 degrees C), time and temperature for the splitless step (0.75 min and 60 degrees C), size of sample (2 microL), and oven temperature program, providing analysis times shorter than 10 min. Aspects such as the stability of the solutions, linearity, accuracy, and precision are examined in order to validate this method. Peak purity and detection and quantitation limits are also assessed using mass selective detection. The scope of the validated method is tested in the analysis of pharmaceutical preparations, with recoveries between 97.5 and 102.5% with regard to their nominal contents.

Nonaqueous capillary electrophoretic separation and thermo-optical absorbance detection of five tricyclic antidepressants and metabolism of amitriptyline by Cunninghamella elegans

We developed a technique based on nonaqueous capillary electrophoresis and laser-based thermo-optical absorbance detection to assay five antidepressants with similar structures and mass-to-charge ratios. A mixture of methanol and acetonitrile with ammonium acetate was essential to achieve baseline resolution of these compounds. We investigated the effects of ammonium acetate concentration, temperature, applied voltage, and capillary length on separation efficiency. The nonaqueous capillary electrophoresis and laser-based thermo-optical absorbance detection technique was used to study the metabolism of amitriptyline by Cunninghamella elegans. Sample preparation procedures were simplified for fast screening of the parent drug and its metabolites. Reproducible electropherograms were obtained from replicate cultures of C. elegans growing in the presence of amitriptyline.

On-line nonaqueous capillary electrophoresis and electrospray mass spectrometry of tricyclic antidepressants and metabolic profiling of amitriptyline by Cunninghamella elegans

An on-line nonaqueous capillary electrophoresis-electrospray mass spectrometry (ESI-MS) technique was developed using a commercial ion spray interface. The nonaqueous capillary electrophoresis ESI-MS system was used to profile tricyclic antidepressants of similar structures and mass-to-charge ratios. We found that pure methanol can be used as a sheath liquid to obtain stable ion spray from nonaqueous capillary electrophoresis. The flow rate of the coaxial nebulizing gas affected baseline signals, separation efficiency, and migration times. Other nonaqueous capillary electrophoresis operating conditions and electrospray parameters were optimized for enhanced baseline separation and high sensitivity detection. The effect of sample stacking on separation and detection was evaluated. The calculated detection limits were approximately 3 pg injected onto the capillary. ESI mass spectra of tricyclic antidepressants from a single quadrupole MS were obtained and elucidated. The information was used to propose fragmentation pathways of the tricyclic antidepressants. The method was also used to analyze the metabolites of amitriptyline produced by the fungus Cunninghamella elegans. Sixteen metabolites were detected and most of them were tentatively identified as demethylated and/or hydroxylated, and/or N-oxidized products.

Postmortem clomipramine: therapeutic or toxic concentrations?

Postmortem blood and liver concentrations of clomipramine were determined in ten cases by high performance liquid chromatography (HPLC). Blood concentrations ranged from 0.21 to 4.9 mg/L, and liver concentrations from 7.0 to 320 mg/kg. Two cases associated with clomipramine toxicity were clearly differentiated from other cases by the analysis of liver. The concentrations of clomipramine in these two cases were 3.3 and 1.8 mg/L in blood, and 280 and 320 mg/kg in liver. The liver concentrations were 10 to 30 fold greater in the deaths associated with drug toxicity compared with the other cases. One case, where cardiac blood was collected in place of femoral blood, showed a high blood concentration (4.9 mg/L), but an arguably therapeutic liver concentration (13 mg/kg). The analysis of femoral blood together with liver provides the best guide as to the significance of post-mortem clomipramine concentrations.

High-performance liquid chromatography of clomipramine and metabolites in human plasma and urine

An isocratic, high-performance liquid chromatography method has been developed for simultaneous determination of the tricyclic antidepressant clomipramine and six metabolites: desmethylclomipramine, 2- and 8-hydroxy-clomipramine, 2- and 8-hydroxydesmethylclomipramine and didesmethyl-clomipramine in plasma and urine. In addition, clomipramine N-oxide was determined in the unconjugated fraction of urine. The method is based on a three-step liquid-liquid extraction, the chromatographic eluent was 30% acetonitrile and 70% aqueous sodium perchlorate solution, pH 2.5, and the UV detection was performed at 220 nm. The method was applied to the analysis of samples followed by oral doses of clomipramine to patients and healthy volunteers.

Post-mortem drug redistribution--a toxicological nightmare

Detailed human case data is presented to illustrate the dramatic extent of the phenomenon of post-mortem drug redistribution. The data suggests that there is a post-mortem diffusion of drugs along a concentration gradient, from sites of high concentration in solid organs, into the blood with resultant artefactual elevation of drug levels in blood. Highest drug levels were found in central vessels such as pulmonary artery and vein, and lowest levels were found in peripheral vessels such as subclavian and femoral veins. In individual cases, in multiple blood samples obtained from ligated vessels, concentrations of doxepin and desmethyldoxepin ranged from 3.6 to 12.5 mg/l and 1.2 to 7.5 mg/l, respectively; amobartital, secobarbital and pentobarbital from 4.3 to 25.8 mg/l, 3.9 to 25.3 mg/l and 5.1 to 31.5 mg/l respectively; clomipramine and desmethylclomipramine from 4.0 to 21.5 mg/l and 1.7 to 8.1 mg/l, respectively and flurazepam 0.15 to 0.99 mg/l; imipramine and desipramine from 4.1 to 18.1 mg/l and 1.0 to 3.6 mg/l, respectively. We conclude that this poorly studied phenomenon creates major difficulties in interpretation and undermines the reference value of data bases where the site of origin of post-mortem blood samples is unknown.

Fly larvae: a new toxicological method of investigation in forensic medicine

Toxicological analyses on a putrefied cadaver are sometimes difficult to achieve because of the absence of blood and urine. In this study, maggots, living material, are proposed as a new medium of investigation in forensic medicine. Five drugs (triazolam, oxazepam, phenobarbital, alimemazine, and clomipramine) were identified and assayed in some tissues of a putrefied cadaver and in the maggots found on and in the body.

Pharmacokinetic patterns of repeated administration of antidepressants in animals. I. Implications for antinociceptive action of clomipramine in mice

The pattern of repeated administration of antidepressants in animals varies from one study to another, making comparison of results difficult. We propose a means of standardizing the pattern of administration for any particular animal, based on a pharmacokinetic study of the antidepressant [here clomipramine (CMI)] in that animal. The plasma half-life (127 min) in the Swiss CD1 mouse was used as a basis for chronic administration, which was strictly every half-life as in clinical use. Daily administration is thus merely repeated acute administration. The antinociceptive action of CMI was compared under four sets of conditions of injection: single, chronic, daily and closely repeated (every 40 min). The antinociceptive effect obtained after an acute injection of CMI (10 or 20 mg/kg i.p.) was increased 2-fold after five chronic injections. Closely repeated injections gave a more marked effect than chronic administration, and daily administration was ineffective. The time course of the antinociceptive action correlated with that of blood and brain levels of CMI and its monodemethylated derivative. The enhancement of the antinociceptive action observed after chronic and closely repeated administration was shown not to be due to any modification of motor activity. It was suppressed by naloxone. Comparison with results reported in the literature shows the benefit of using a well-defined pattern of administration.

Determination of clomipramine and its hydroxylated and demethylated metabolites in plasma and urine by liquid chromatography with electrochemical detection

A procedure for the determination of clomipramine and its 8-hydroxy, demethyl, 8-hydroxydemethyl and didemethyl metabolites in plasma and urine by high-performance liquid chromatography with electrochemical detection is described. A 1-ml plasma or urine sample is made alkaline with a carbonate buffer (pH 9.8) and extracted with 20% ethyl acetate in n-heptane. After back-extraction into an acid phosphate buffer (pH 2.4), an aliquot is injected into a 5-microns ion-paired reversed-phase column and eluted with a mobile phase containing a phosphate buffer with tetramethylammonium chloride-acetonitrile (57:43). The detection is coulometric with a first cell at +0.40 V, a second at +0.73 V and a guard cell set at 0.75 V for oxidation of the mobile phase. The method provides recoveries in the general range of 80-110% and a day-to-day precision of 3.7-8.8%, depending on the compound. The minimum quantifiable level for all compounds was 0.2 ng/ml with a 20-microliters injection. Steady-state plasma concentration data and urinary levels are reported for 24 depressed patients receiving daily either 75-150 mg orally or 50-75 mg by infusion.

A fatal overdose with clomipramine

A death attributed to self administration of toxic amounts of clomipramine is reported. Analysis of post mortem blood showed clomipramine at a concentration of 540 ng/mL and its active metabolite, N-desmethylclomipramine, at a concentration of 580 ng/mL. The corresponding concentrations of the parent compound and metabolite in the urine were only 350 ng/mL and 700 ng/mL, respectively. These blood results are construed to represent minimum lethal concentrations for the two combined compounds.

Determination of clomipramine and desmethyl-clomipramine in plasma or urine by the double-radioisotope derivative technique

A double radioisotope derivative method was developed for the determination of clomipramine and desmethyl-clomipramine in plasma or urine. After addition of 14C-labeled clomipramine and desmethyl-clomipramine as internal standards and extractive isolation of both compounds, desmethyl-clomipramine is acetylated with [3H]acetic anhydride. The [3H]acetamide is separated from clomipramine by thin-layer chromatography and its radioactivity is measured. Clomipramine, extracted from the cilica gel, is reacted with trichloroethyl chloroformate. The urethane is saponified and decarboxylated. The resulting desmethyl-clomipramine is acetylated with [3H]acetic anhydride. The [3H]acetamide is purified by thin-layer chromatography and its radioactivity is measured. The sensitivity of the method is 15 mug/liter for clomipramine and 2 mug/liter for desmethyl-clomipramine. Its specificity was made sure by a cross-check with a gas chromatography-mass spectrometry technique.