Search results for "quantitative analysis"
showing 10 items of 304 documents
Qualitative and quantitative analysis of the phenazepam tablets 12 years after manufacturing
2007
Role of hydrophobicity on the monoamine receptor binding affinities of central nervous system drugs: a quantitative retention-activity relationships …
2004
Abstract Biological action and activity reflect an aspect of the fundamental physicochemical properties of the bioactive compounds. As an alternative to classical QSAR studies, in this work different quantitative retention–activity relationships (QRAR) models are proposed, which are able to describe the role of hydrophobicity on the binding affinity to different brain monoamine receptors (H 1 -histamine, α 1 -noradrenergic and 5-HT 2 -serotonergic) of different families of psychotherapeutic drugs. The retention of compounds is measured in a biopartitioning micellar chromatography (BMC) system using Brij-35 mobile phases. The adequacy of the QRAR models developed is due to the fact that both…
Structure and Evolution of a European Parliament via a Network and Correlation Analysis
2016
We present a study of the network of relationships among elected members of the Finnish parliament, based on a quantitative analysis of initiative co-signatures, and its evolution over 16 years. To understand the structure of the parliament, we constructed a statistically validated network of members, based on the similarity between the patterns of initiatives they signed. We looked for communities within the network and characterized them in terms of members’ attributes, such as electoral district and party. To gain insight on the nested structure of communities, we constructed a hierarchical tree of members from the correlation matrix. Afterwards, we studied parliament dynamics yearly, wi…
Study of various indicating redox systems on the indirect flow-injection biamperometric determination of pharmaceuticals
1999
Abstract The reversible redox couples (Fe(III)/Fe(II); Ce(IV)/Ce(III); Fe(CN) 6 3– /Fe(CN) 6 4− ; I 2 /I − ; Br 2 /Br − and VO 3 − /VO 2+ ) were studied as indicating redox systems for biamperometric determination of paracetamol in a flow injection assembly. Considering the selectivity of assayed systems against excipients and antioxidants that typically are presented in pharmaceutical formulations (e.g. sucrose, glucose, ascorbic acid and hydrogen sulphite) the systems Fe(III)/Fe(II) and VO 3 − /VO 2+ were selected for the determination of the drug. The sample was injected into a carrier which merged with the oxidant stream where the drug was oxidised by excess oxidant. The observed signal…
Quantitative atomic force microscopy
2017
A variety of atomic force microscopy (AFM) modes is employed in the field of surface science. The most prominent AFM modes include the amplitude modulation (AM) and the frequency modulation (FM) mode. Over the years, different ways for analyzing data acquired with different AFM modes have been developed, where each analysis is usually based on mode-specific assumptions and approximations. Checking the validity of the seemingly different approximations employed in the various analysis methods can be a tedious task. Moreover, a straightforward comparison of data analyzed with different methods can, therefore, be challenging. Here, we combine the existing evaluation methods which have been sep…
Short-Term Stability of Lysergic Acid Diethylamide (LSD), N-Desmethyl-LSD, and 2-Oxo-3-hydroxy-LSD in Urine, Assessed by Liquid Chromatography–Tandem…
2002
Lysergic acid diethylamide (LSD) is one of the most potent hallucinogenic agents known. Recently, data on emergency department episodes related to the use of drugs commonly thought as “club drugs” have also included LSD (1). Confirmation of LSD use by testing biological fluids is still an analytical challenge because of its extensive, rapid metabolism and its instability (2)(3)(4). After ingestion of a typical street dose (40–120 μg), the concentration of LSD in urine falls to <1 μg/L within a few hours (2)(5)(6). Recently, N -desmethyl-LSD (nor-LSD) and 2-oxo-3-hydroxy-LSD (O-H-LSD) have been identified as LSD metabolites in human urine (7)(8). Measured nor-LSD concentrations were reported…
Time-Gated Raman Spectroscopy for Quantitative Determination of Solid-State Forms of Fluorescent Pharmaceuticals
2018
Raman spectroscopy is widely used for quantitative pharmaceutical analysis, but a common obstacle to its use is sample fluorescence masking the Raman signal. Time-gating provides an instrument-based method for rejecting fluorescence through temporal resolution of the spectral signal and allows Raman spectra of fluorescent materials to be obtained. An additional practical advantage is that analysis is possible in ambient lighting. This study assesses the efficacy of time-gated Raman spectroscopy for the quantitative measurement of fluorescent pharmaceuticals. Time-gated Raman spectroscopy with a 128 X (2) X 4 CMOS SPAD detector was applied for quantitative analysis of ternary mixtures of sol…
Quantitative structural analysis of trabecular alveolar bone in the mandible by multidetector computed tomography: Differences according to tooth pre…
2019
Background and objective: There is a lack of quantitative measures of the quality of alveolar trabecular bone, an important factor in implantology. This study aimed to develop a method of objectively assessing the quality of trabecular bone by means of image processing and structural analysis of multidetector computed tomography images and to establish differences between tooth types and tooth presence/absence. Materials and methods: We analyzed 20 patients who underwent multidetector computed tomography to evaluate mandibular bone and tooth positioning. Image analysis included automatic segmentation of the mandible, obtainment of sections perpendicular to the dental arch, and structural an…
Food and Environment: Trace Element Content of Hen Eggs from Different Housing Types
2013
AbstractEleven trace elements (Ba, Cu, Fe, Mn, Ni, Pb, Rb, Se, Sr, V, Zn) were quantitatively determined in hen egg samples collected from different poultry housing types (large-scale poultry farms, organic farms and domestic farms) over the territory of Latvia. Samples were wet digested and quantitatively analysed by total reflection X-ray fluorescence spectrometry (TXRF). The accuracy of analytical method was verified with analysis of certified reference material NCS ZC73017 (GSB-10)-Apple. The most variable range of concentrations and the highest content of elements were determined for hen egg samples derived from organic farms, while egg samples from domestic farms and poultry farms mos…
Analysis of Diuretics in Urine by Column-Switching Chromatography and Fluorescence Detection
1997
The potential of column-switching chromatography and fluorescence detection for the analysis of diuretics in urine is evaluated. Sample cleanup and chromatographic parameters have been optimized to achieve maximum sensitivity for the detection and quantification of some relevant diuretics. On the basis of these studies, an on-line procedure for the simultaneous determination of amiloride, furosemide, bumetanide and triamterene is presented. The linearity, precision, accuracy and sensitivity of the method are discussed. The utility of the described approach has been tested by analysing urine samples obtained after administration of bumetanide.