1,720,964 research outputs found
Simultaneous high-performance liquid chromatographic determination of olanzapine and lamotrigine in plasma of bipolar patients
No full textAn original method based on the use of high-performance liquid chromatography with both coulometric and diode array detection has been developed for the therapeutic drug monitoring of patients with bipolar disorders being treated with olanzapine and lamotrigine. Chromatographic separation was achieved on a reversed-phase C8 column (150 x 4.6 mm internal diameter, 5 microm) using a mobile phase composed of methanol (27%) and a 50.0 mmol/L, pH 3.5 phosphate buffer (73%). For the analysis of olanzapine and its main metabolite, N-desmethylolanzapine, a coulometric detector was used, with electrode 1 set at -200 mV and electrode 2 at +500 mV. Lamotrigine was determined using a diode array detection at 220 nm. The two detectors were connected in series. For the analysis of biological samples, a clean-up procedure was implemented by means of solid-phase extraction using phenyl cartridges and eluting the analytes with methanol; only a small volume of plasma (150 microL) was needed to analyze both olanzapine and lamotrigine. Linear responses were obtained between 0.1 and 50.0 ng mL(-1) for olanzapine, 0.1 and 25.0 ng mL(-1) for N-desmethylolanzapine, and between 0.25 and 10.0 microg mL(-1) for lamotrigine. The extraction yield values were always higher than 90% for all the analytes, with precision (expressed as relative standard deviation values) lower than 3.4%. The method was applied successfully to some human plasma samples drawn from bipolar patients undergoing combined therapy with the two drugs. Satisfactory values for accuracy were obtained, with mean recovery higher than 91%. Thus, the method appears suitable for the investigation of the chemical-clinical correlations in patients receiving therapy with olanzapine and lamotrigine
Simultaneous high-performance liquid chromatographic determination of olanzapine and lamotrigine in plasma of bipolar patients
No full textRapid HPLC analysis of the antiepileptic lamotrigine and its metabolites in human plasma
No full textDetermination of selected phenothiazines in human plasma by solid-phase extraction and liquid chromatography with coulometric detection.
No full textA new analytical method, based on liquid chromatography with coulometric detection, has been developed and applied to the determination of selected phenothiazines (chlorpromazine, promazine, fluphenazine and levomepromazine) in human plasma. The drugs were separated on a Discovery pentafluorophenylpropyl column, using a mobile phase composed of acetonitrile (32%) and a pH 1.9 phosphate buffer (68%). Promethazine was used as the internal standard. Detection was carried out at an oxidation potential of +0.500 V. A novel clean-up procedure was developed by means of solid-phase extraction, using cyanopropyl cartridges, which gave good extraction yield for all the analytes, with absolute recovery values higher than 91.0%. The detector response was linear over a plasma concentration range of 0.5-250.0 ng mL(-1) for chlorpromazine, promazine and levomepromazine and of 0.2-4.0 ng mL(-1) for fluphenazine. Precision results, expressed by the intra-day and the inter-day relative standard deviation values, were good, being lower than 3.9%. Accuracy data were satisfactory as well. The method has been successfully applied to the analysis of drug plasma levels of psychiatric patients undergoing therapy with selected phenothiazine
Thromboembolic disease developing during oral contraceptive therapy in young females with antiphospholipid antibodies.
No full textRapid HPLC analysis of the antiepileptic lamotrigine and its metabolites in human plasma
No full textA liquid chromatographic method with diode array detection (DAD) has been developed for the analysis of the antiepileptic agent lamotrigine (LTG) and its metabolites, lamotrigine 2-N-glucuronide and 2-N-methylated in plasma samples. The analytes were separated on a C8 RP column, using a mobile phase composed of methanol and a 0.45 mM, pH 3.5 phosphate buffer containing 0.17% triethylamine (24:76 v/v). Melatonin was used as the internal standard (IS). The DAD detector was set at 220 nm for the detection of all the analytes. A simple protein precipitation with methanol guaranteed high extraction yield values (>90%) and good purification from matrix interference. Good linearity was obtained in the 0.1-15.0 microg/mL range for LTG and lamotrigine 2-N-glucuronide and in the 0.1-2.0 microg/mL range for lamotrigine 2-N-methylated. The analytical method was validated in terms of precision, extraction yield, and accuracy. These assays gave RSD% values for precision always lower than 4.3% and mean accuracy higher than 80%. The method seems to be suitable for the analysis of plasma samples from patients treated with Lamicta
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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