Determination of total iron in food samples after flow injection preconcentration on polyurethane foam functionalized with N,N-bis(salicylidene)-1,3-propanediamine.

A highly selective flow injection sorption system was developed for the fast determination of total iron in food samples. Iron (III) was reduced to iron (II) by ascorbic acid and preconcentrated on a mini-column packed with polyurethane foam (PUF) functionalized with N,N-bis(salicylidene)-1,3-propanediamine (SPDA). The retained Fe (II) was eluted with hydrochloric acid and subsequently reacted to 2,4,6-tri(2'-pyridyl)-1,3,5-triazine (TPTZ) then measured at 593 nm. The procedure has resulted preconcentration factor 36, sample frequency 20 h(-1) and detection limit 18 µg L(-1). The precision (RSD) was found to be 5.7% and 3.1% at concentration levels 0.1 and 5.0 µg mL(-1) iron (II), respectively. Finally, the method was successfully applied to determination of total iron in reference material and food samples.

Cationic polyelectrolyte copolymer modified polyurethane foam for flow injection preconcentration and separation of trace amounts of ß-lactam antibiotics.

A more sensitive flow injection preconcentration method has been developed for the determination of four ß-lactam antibiotics (BLAs) namely cefaclor, cefotaxime, amoxicillin and ampicillin in urine, pharmaceuticals and milk. A mini-column packed with PUF functionalized with the cationic polyelectrolyte, poly(N-chloranil N,N,N',N'-tetramethylethylene diammonium dichloride) PCTDD, was utilized for selective preconcentration. The detection limits with this method were 3.3, 3.8, 5.1 and 7.0 ng mL(-1) and enrichment factors were 38, 21, 39, and 36 for cefaclor, cefotaxime, amoxicillin and ampicillin, respectively with a sample throughput of 12 h(-1) for all BLAs. Moreover, the BLAs were successfully separated by isocratic elution using a micellar mobile phase. Application of the method developed has resulted in recovery values in the range 95%-109% (RSD≤8.7), 83%-99% (RSD≤9.7) and 91%-103% (RSD≤4.0) for urine, pharmaceuticals and milk samples, respectively.

Determination of molybdenum in extracts of soil and sewage sludge CRMs after fractionation by means of BCR modified sequential extraction procedure.

A modified three-step sequential extraction procedure proposed by the Commission of European Communities Bureau of Reference (BCR) was applied to certified reference materials of three different soil groups (rendzina, luvisol, and cambisol) and sewage sludge of different compositions originating from a municipal water treatment plant in order to assess potential mobility and the distribution of molybdenum in the resulting fractions. In the soils examined, molybdenum was present almost entirely in the mineral lattice, the content of molybdenum in the fractions of the studied reference materials of sludges was predominant in the fraction, represents Mo bound to organic matter and sulphide. The internal check of accuracy was performed on the results of the sequential extraction by comparing of the extractable amounts of molybdenum in the sequential procedure with the results of the pseudototal digestion of original samples. The recovery ranged from 96 to 101% and the precision (RSD) in the extracts was below 10%.

[Therapeutic drug monitoring (TDM) of psychotropic drugs: a consensus guideline of the AGNP-TDM group]. / Le dosage plasmatique des médicaments psychotropes a des fins thérapeutiques: recommandations du groupe d'experts AGNP-TDM.

In psychiatry, therapeutic drug monitoring (TDM) is an established procedure for most psychotropic drugs. However, as its use in everyday clinical practice is far from optimal, the AGNP-TDM group has worked out consensus guidelines to assist psychiatrists and laboratories involved in drug analysis. Based on a thorough analysis of available literature, 5 levels of recommendation were defined with regard to TDM of psychoactive drugs, from 1) (strongly recommended) to 5) (not recommended). A list of indications for TDM, alone or in combination with pharmacogenetic tests is presented. Instructions are given with regard to preparation of TDM, analytical procedures, reporting and interpretation of results and the use of information for patient treatment. Using the consensus guideline will help to ensure optimal clinical benefit of TDM.

The AGNP-TDM expert group consensus guidelines: therapeutic drug monitoring in psychiatry.

Therapeutic Drug Monitoring (TDM) is a valid tool to optimise pharmacotherapy. It enables the clinician to adjust the dosage of drugs according to the characteristics of the individual patient. In psychiatry, TDM is an established procedure for lithium, some antidepressants and antipsychotics. In spite of its obvious advantages, however, the use of TDM in everyday clinical practice is far from optimal. The interdisciplinary TDM group of the Arbeitsgemeinschaft fur Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) has therefore worked out consensus guidelines to assist psychiatrists and laboratories involved in psychotropic drug analysis to optimise the use of TDM of psychotropic drugs. Five research-based levels of recommendation were defined with regard to routine monitoring of plasma concentrations for dose titration of 65 psychoactive drugs: (1) strongly recommended, (2) recommended, (3) useful, (4) probably useful and (5) not recommended. A second approach defined indications to use TDM, e. g. control of compliance, lack of clinical response or adverse effects at recommended doses, drug interactions, pharmacovigilance programs, presence of a genetic particularity concerning the drug metabolism, children, adolescents and elderly patients. Indications for TDM are relevant for all drugs either with or without validated therapeutic ranges. When studies on therapeutic ranges are lacking, target ranges should be plasma concentrations that are normally observed at therapeutic doses of the drug. Therapeutic ranges of plasma concentrations that are considered to be optimal for treatment are proposed for those drugs, for which the evaluation of the literature demonstrated strong evidence. Moreover, situations are defined when pharmacogenetic (phenotyping or genotyping) tests are informative in addition to TDM. Finally, practical instructions are given how to use TDM. They consider preparation of TDM, analytical procedures, reporting and interpretation of results and the use of information for patient treatment. Using the consensus guideline will help to ensure optimal clinical benefit of TDM in psychiatry.

Therapeutic monitoring of psychotropic drugs: an outline of the AGNP-TDM expert group consensus guideline.

TDM of psychotropic drugs is widely used, but there is little consensus regarding its optimal use in the clinical context. This prompted a multidisciplinary group comprised of clinical biochemists, clinical pharmacologists, and psychiatrists of the AGNP (Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie) to provide a consensus guideline. This will allow clinical psychiatrists, practitioners, and laboratory directors involved in psychopharmacotherapy to optimize TDM of antidepressants, antipsychotics, and opioid substituents. Recommendations are also given on the combined use of TDM and pharmacogenetic tests.

In vivo efficacy in airway disease models of N-(3,5-dichloropyrid-4-yl)-[1-(4-fluorobenzyl)-5-hydroxy-indole-3-yl]-glyoxylic acid amide (AWD 12-281), a selective phosphodiesterase 4 inhibitor for inhaled administration.

N-(3,5-Dichloro-pyrid-4-yl)-[1-(4-fluorobenzyl)-5-hydroxy-indole-3-yl]-glyoxylic acid amide (AWD 12-281) is a highly potent and selective phosphodiesterase 4 (PDE4) inhibitor that was designed to have a metabolic profile that was optimized for topical administration. The aim of the current study was to explore the pharmacological profile of intratracheally administered AWD 12-281 in different models of asthma and chronic obstructive pulmonary disease (COPD) in comparison with steroids. To assess the anti-inflammatory potential of AWD 12-281, the antigen-induced cell infiltration in bronchoalveolar lavage fluid (BALF) of Brown Norway rats was determined. AWD 12-281 (ID50 of 7 microg/kg i.t.) as well as beclomethasone (0.1microg/kg i.t.) suppresses late-phase eosinophilia when administered intrapulmonary. Furthermore, AWD 12-281 has also strong anti-inflammatory properties when tested in lipopolysaccharide-induced acute lung neutrophilia in Lewis rats (ID50 of 0.02 microg/kg i.t.), ferrets (ID50 of 10 microg/kg i.t.), and domestic pigs (2-4 mg/pig i.t. or 1 mg/kg i.v.). In pigs, AWD 12-281 was as effective as beclomethasone (0.4 mg/pig i.t.) and dexamethasone (0.28 mg/kg i.v.), although at 3 to 10 times the dosage. The bronchodilatory activity of AWD 12-281 was assessed in sensitized guinea pigs. AWD 12-281 (1.5 mg/kg i.t., 1-h pretreatment) inhibited allergen-induced bronchoconstriction by 68% (parameter airway resistance). In sensitized BP-2 mice AWD 12-281 abolished the allergen-induced bronchial hyperresponsiveness and eosinophilia in BALF, showing dose dependence. When given orally, i.v. or i.t., AWD 12-281 has a considerably lower emetic potential than cilomilast in ferrets and roflumilast in pigs. When given topically by inhalation, no emesis could be induced in dogs up to the highest feasible dose (15 mg/kg in 50% lactose blend). These results indicate that AWD 12-281 is a unique potential new drug for the topical treatment of asthma and COPD.

Therapeutic drug monitoring of tricyclic antidepressants: how does it work under clinical conditions?

Therapeutic drug monitoring (TDM) of tricyclic antidepressants (TCA) is established in the treatment of depression to optimize outcome and safety. However, there are few reports on TDM under naturalistic clinical conditions. In the present study, we investigated a TDM group (TDM) and a randomly assigned parallel group without TDM (no-TDM) while on TCA treatment. Serum levels were analyzed in both cohorts, but feedback and dose recommendation were only provided for the TDM group. Serum levels of TCA were assessed by high-performance liquid chromatography (HPLC). The outcome was measured weekly using the Hamilton Depression Rating Scale (HAMD), the Clinical Global Impressions Scale (CGI), and the UKU side-effect scale. 84 patients with depressive disorder according to DSM-IV were recruited in three centers (TDM, n = 43; no-TDM, n = 41; mean age 49.9 +/- 13.2 years, 63.1 % female). Patients were treated with either amitriptyline (n = 69) or doxepin (n = 15); the mean dosage at endpoint was 126 +/- 35 mg and 155 +/- 47 mg, respectively. The mean study duration was 21 +/- 8 days. Both groups improved according to HAMD (from 25.2 +/- 8.4 at baseline to 12.0 +/- 7.4 at endpoint) and CGI scores (68 % responders). Moderately severe or severe side effects occurred in 16 % of patients. Adequate dose adjustment was significantly higher in the TDM group (60 % vs. 46 %, p < 0.05); this led to a significantly higher rate of therapeutic serum levels in the TDM group (58 % vs. 44 %, p < 0.05). Direct effects of TDM were not found for effectiveness. Therapeutic TCA serum levels over weeks one to three, however, were associated with significantly better outcome at endpoint (p < 0.05) as measured with changes in the HAMD or CGI response rates from baseline to endpoint. Finally, considerable side effects occurred significantly more often when serum levels were above the therapeutic range (27 % vs. 11 %; p < 0.01). We conclude that treating depression with TCA can be optimized by early TDM, which is superior to clinical judgment on its own. Since the psychiatrists in charge were less than completely "compliant" to the recommendations provided together with serum levels, the effect could be more pronounced than this study shows. The results encourage further studies in order to optimize antidepressant pharmacotherapy when using TDM appropriately.

Increased surfactant protein D in rat airway goblet and Clara cells during ovalbumin-induced allergic airway inflammation.

BACKGROUND: Structural remodelling of airways in asthma that follows inflammation may be affected by surfactant protein D (SP-D)-mediated effects on the immune response. OBJECTIVE: To determine potential sites of SP-D interaction with the pulmonary immune response, we examined the distribution of immunoreactive SP-D in an experimental model of allergen-induced airway inflammation using immunohistochemistry, biochemical methods and in situ hybridization. METHODS: The experimental model used subcutaneous injection of ovalbumin in adult rats, which induced an airway response to inhaled nebulized ovalbumin. Three groups of rats (ovalbumin, ovalbumin + dexamethasone and saline) were challenged thrice weekly for 3 weeks. A fourth group of seven rats (naive) were taken from the same delivery of rats as the other groups. Lungs were then lavaged to determine total cell count, eosinophil count, ovalbumin-specific IgE by enzyme-linked immunosorbent assay and SP-D by immunoblot. Tissue samples were fixed and embedded, and sections were studied for the infiltration of eosinophils and for expression of SP-D protein by histochemistry and mRNA by in situ hybridization. RESULTS: Ovalbumin induced perivascular and peribronchiolar eosinophilia which could be prevented by dexamethasone treatment. In addition, the ovalbumin-specific IgE levels in serum and bronchoalveolar lavage fluid of ovalbumin-challenged animals were enhanced. Increased amount of SP-D in lavage and tissue, particularly in type II pneumocytes, in Clara cells and, surprisingly, in hyperplastic goblet cells of inflamed lungs was found. SP-D mRNA was detected in goblet cells as well as in type II pneumocytes and Clara cells. Dexamethasone treatment did not affect level of SP-D immunoreactivity. CONCLUSION: SP-D accumulation is increased in this model of allergen-induced eosinophilia, both in upper and lower airways. The increase is unaffected by dexamethasone.

Long-term effects of tricyclic antidepressants on norepinephrine kinetics in humans.

The nature of the discrepancy between short-term pharmacokinetic data (hours) on the one hand and long-term pharmacodynamic effects and the clinical latency of therapeutic amelioration on the other hand by tricyclic antidepressants is still unclear. A relapsed sensibilization of neuronal, immunologic, and endocrinologic systems by changes in receptor sensitivity has been proposed. However, the discrepancy may have a strong influence on many aspects of antidepressive therapy in humans. The aim of our study was to demonstrate long-term pharmacodynamic effects by single-dose antidepressive treatment in humans by measuring heart rate parameters in response to neurochemical parameters. 25 young healthy probands, divided into three treatment groups (amitriptyline, n = 10; clomipramine, n = 10; placebo, n = 5), were challenged by a noradrenaline infusion test at baseline and one and 21 days after a single dose of antidepressant. Heart rate and blood pressure as well as plasma levels of antidepressants and of noradrenaline and adrenaline were measured in response to noradrenaline infusion test. Noradrenaline infusion rate to reach an increase in blood pressure of RR > 30 mmHg was significantly decreased for both antidepressants on day 1. The same effect was true for the amitriptyline group on day 21. Furthermore, pretreated probands respond to antidepressants in a different way when compared to untreated probands. Like depressed patients under therapy they respond with a dramatic increase in sensitivity of the alphal-adrenergic receptor. We could demonstrate that the long-term pharmacodynamic effects have a strong influence on antidepressive therapy. A prolonged pharmacodynamic effect influences further clinical studies as well as our thinking about adverse drug effects. In clinical studies, washout periods may be to short to overcome the benefits of a previous medication. Adverse drug effects are often seen during periods when drugs were changed. The negative effect may be due to an additional effect of both medicaments.

[Non-fatal effect of highly toxic amitriptyline level after suicide attempt. A case report]. / Nichtletale Wirkung hochtoxischer Amitriptylin-Spiegel nach Suizidversuch. Ein Fallbericht.

Pharmacotherapeutic intervention in psychiatric patients often bears the risk of drug abuse for suicide attempts. Especially intoxication with tricyclic antidepressants, e.g., amitriptyline, may cause severe complications such as cardiac arrhythmia. Even under intensive care conditions, 2-3% of intoxicated patients still die. Here, we report on a depressed female patient who, thanks to timely and intense intervention, survived a suicide attempt with amitriptyline despite highly toxic plasma levels.

The loudness dependency of the auditory evoked N1/P2-component as a predictor of the acute SSRI response in depression.

RATIONALE: A serotonergic dysfunction is supposed to play a pathogenetic role in depression, but there is a considerable number of non-responders in the acute treatment of depression with serotonergic agents like SSRI. Thus, an indicator of central serotonergic activity could lead to a more specific pharmacological treatment of depression. In animal and human data there is a growing amount of evidence that a strong loudness dependency of late auditory evoked potentials (LDAEP) is an indicator of low serotonergic activity and vice versa. OBJECTIVE: In 29 depressive inpatients (DSM-III-R diagnosis 296.x in 28 patients, 300.4 in one patient), the hypothesis was tested that a strong LDAEP prior to treatment can predict a better clinical outcome under SSRI treatment over 4 weeks. RESULTS: Patients with a strong pre-treatment LDAEP had a significantly greater decrease of depressive symptoms (Hamilton Scale for Depression) after 4 weeks than patients with a flat LDAEP. Significantly more responders fell into the group with a high LDAEP. Contrary to what might be expected, a second recording in a subsample of 19 patients after 4 weeks of treatment failed to show changes in the LDAEP. CONCLUSION: Our finding confirms the hypothesis that a strong LDAEP, indicating a low serotonergic activity, is related to a favorable response to acute SSRI treatment in depression. The LDAEP is a promising tool for the prediction of response to serotonin agonists in depression and it seems to be of clinical importance.

The serotonin syndrome scale: first results on validity.

As a modification of the diagnostic criteria of the serotonin syndrome proposed by Sternbach, we developed the Serotonin syndrome scale for the operationalized assessment of both the presence and the severity of the core symptoms of the serotonin syndrome. In a first study on the validity of this scale, the relationships between the serotonin syndrome score (SSS) and both the paroxetine plasma levels (n = 42) and the loudness dependence of the auditory evoked potentials (LDAEP; n = 24) were investigated in depressed patients treated with paroxetine. A strong LDAEP is supposed to indicate low central serotonergic neurotransmission, and vice versa. The SSS was positively related to paroxetine plasma levels and negatively to the LDAEP. Both results support the validity of the serotonin syndrome scale. Using a SSS > 6 as diagnostic criterion, mild serotonin syndromes were diagnosed in 5 of our 42 patients. The Serotonin syndrome scale may become a useful tool for clinicians and scientists dealing with the serotonin syndrome.

Unstable anticoagulation in the course of amitriptyline treatment.

A potential drug-drug interaction between the tricyclic antidepressant amitriptyline and the oral anticoagulant phenprocoumon, causing intensified hypo- and/or hyperprothrombinemic effects, was investigated. In seven patients simultaneously receiving amitriptyline and phenprocoumon the course of the Quick values and the amitriptyline and phenprocoumon dosages were registered. The resulting data represented graphically was additionally compared with data and diagrams gained from a control group of seven phenprocoumon patients not receiving amitriptyline. Whereas in the control group the average Quick values (or the target International Normalized Ratio) lay within the required therapeutic range, massive fluctuations were seen in the amitriptyline-treated patients. These fluctuations did not disappear until the amitriptyline medication was discontinued. Whether our findings are actually due to a clinically relevant drug-drug interaction needs to be investigated in further controlled studies based on a larger number of patients, the more so as no comparable investigations and only few references to this subject are to be found in the literature. Should an amitriptyline influence on the frequently prescribed coumarin derivative be proven, an increased risk of rethrombosis or bleeding complications in patients receiving both amitriptyline and phenprocoumon would appear to be indicated.

Determination of gaseous nitrogen in gas mixtures using low pressure microwave induced plasma emission spectrometry.

A microwave induced plasma emission spectrometer operating at low energy (30 W) and low plasma gas pressure (2.5.10(-2) Pa) has been used for the quantitative measurement of molecular nitrogen in natural gases. The samples have been introduced into the plasma using a counterflow principle to produce emission spectra of diatomic molecular fragments in low excitation states (advantage: minimized interferences). The N(2) concentration has been determined by measuring the intensity of the N(2)-line at 337.13 nm (C(3)Pi(u)-B(3)Pi(g)-system; (0,0)vibrational transition) and of the NH-line at 336.03 nm (A(3)Pi(i)-X(2)Sigma(-)-system; (0,0)-vibrational transition). A linear correlation between concentration and signal intensities has been obtained in the range of 0.00% to 14.24% (v/v). The method possesses a detection limit of 0.01 ppm (v/v) for the determination of N(2), and a reproducibility of 1.33% (RSD).

Assay for maprotiline in human serum with improved sensitivity and selectivity.

The use of a photoreactor and fluorescence detection enables measurement of the tetracyclic antidepressant drug 3-(9,10-dihydro-9,10-ethanoanthracene-9-yl)-N-methylpropylamine (maprotiline) with a sensitivity of 100 pg/ml serum. This detection system is highly specific and enables the measurement of very low concentrations in the presence of high concentrations of other drugs that are often found in patient samples. The mean free portions of maprotiline and desmethylmaprotiline were found to be 2.2% and 1.5%, respectively.

Schizophrenic patients treated with high dose phenothiazine or thioxanthene become deficient in polyunsaturated fatty acids in their thrombocytes.

Total fatty acids were analysed in thrombocytes of schizophrenic patients treated with a "high dose" or "low dose" monotherapy of neuroleptic drugs phenothiazine or thioxanthene. The ratio of the very long chain fatty acid hexacosanoic acid to the long chain fatty acid docosanoic acid (C26:0/C22:0) increased in the "high dose" and "low dose" groups as compared to healthy untreated controls (P less than 0.05). The polyunsaturated fatty acid arachidonic acid decreased in the "high" and "low dose" groups (P less than 0.01 and P less than 0.05). The polyunsaturated fatty acids alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid were not detectable in most of the "high dose" schizophrenic patients, however, they were found in the "low dose" group and in the controls. There was a negative correlation between the daily dosage of phenothiazine and the percentages of the polyunsaturated fatty acids arachidonic acid and alpha-linolenic acid+eicosapentaenoic acid+docosahexaenoic acid in thrombocytes (r = -0.87, P less than 0.01 and r = -0.81, P less than 0.01). Two patients of the "high dose" group with an especially high and long lasting monotherapy of neuroleptics were nearly devoid of polyunsaturated fatty acids in their thrombocytes. Untreated schizophrenic patients exhibited a fatty acid pattern in their thrombocytes not markedly different from that of the healthy untreated control group. We conclude that neuroleptic drugs phenothiazine or thioxanthene can alter the fatty acid pattern of thrombocytes.

Influence of neuroleptics on the metabolism of tricyclic antidepressants--in vitro experiments with rat liver microsomes.

The influence of two neuroleptics--the phenothiazine perazine and the butyrophenone haloperidol--on the metabolism of the tricyclic antidepressants amitriptyline (AMI), imipramine (IMI), and chlorimipramine (CMI) was studied in vitro in isolated liver microsomes of female Sprague-Dawley rats. The rats were pretreated over 10 days with either NaCl solutions or with 1, 3, and 10 mg/kg haloperidol or 5 and 15 mg/kg perazine, respectively. The microsomal fraction was incubated with various concentrations of antidepressants. The drugs and their metabolites were analyzed by high-performance liquid chromatography (HPLC). Neither pretreatment with haloperidol nor perazine had any significant influence on the demethylation and N-oxidation activity of the microsomes. Benzylic 10-hydroxylation of AMI or IMI or 10- and 11-hydroxylation of CMI was inhibited significantly by pretreatment with perazine, as was 2-hydroxylation of IMI and CMI, whereas 8-hydroxylation of CMI was not influenced. The inhibition was dose dependent. With haloperidol, only the high dose of 10 mg/kg caused a significant inhibition of benzylic 10-hydroxylation, whereas phenolic hydroxylation was not influenced. The inhibition was much lower than for perazine. Comparing the results with pharmacokinetic studies in humans revealed a good agreement in metabolic pathways. The study could therefore be important in the choice of neuroleptic drugs in combination therapy.

Comparison of the metabolism of the three antidepressants amitriptyline, imipramine, and chlorimipramine in vitro in rat liver microsomes.

The metabolism of the tricyclic antidepressants amitriptyline (AMI), imipramine (IMI), chlorimipramine (CMI) and some of their metabolites was studied in vitro in isolated liver microsomes of female Spraque-Dawley rats. Nine metabolites of AMI, seven metabolites of IMI, and 11 metabolites of CMI were quantitatively determined with high-performance liquid chromatography. The main metabolic reactions, mediated by an NADPH generating system, were hydroxylation, demethylation, and N-oxidation. The ratio of these reactions was different for the three drugs. AMI was hydroxylated more than CMI and CMI more than IMI. The order for demethylation was CMI greater than AMI = IMI, the order for N-oxidation IMI greater than CMI less than or equal to AMI. The substrate dependence of metabolism was investigated. Demethylation and N-oxidation increased proportionally to increasing substrate concentrations, whereas formation of hydroxylated metabolites became saturated (in the concentration range of 10(-6)-10(-5) M). The in vitro metabolism was compared with the in vivo metabolism in humans, reflected by the plasma concentrations of these drugs and their metabolites. A good agreement in metabolic pathways was found.