Search results for "Calibration"
showing 10 items of 890 documents
Spectrophotometric Determination of Hydralazine with 2-Hydroxy-1-naphthaldehyde in Pharmaceuticals
1991
Abstract A new extraction-spectrophotometric method for the determination of hydralazine, based on its reaction with 2-hydroxy-1-naphthaldehyde at 25 °C, is described. The calibration curve was linear between 0.4 and 6 mg/mL of hydralazine. The molar absorbtivity of the product at 408 nm is 40 900 L · mol − 1 · cm − 1 . The method described was applied to the analysis of hydralazine in pharmaceutical preparations containing reserpine, hydrochlorothiazide, bendrofluorthiazine, propranolol, and other substances. The agreement with the U.S.P. XXI method was satisfactory for tablets and injections, but not for pellets.
Determination of lecithin and soybean oil in dietary supplements using partial least squares-Fourier transform infrared spectroscopy.
2008
Lecithin and soybean oil in dietary supplements were determined by Fourier transform infrared spectrometry transmission measurements in dichloromethane in combination with a partial least squares (PLS) regression. Two different PLS models were developed, using 16 synthetic mixtures of analytes in dichloromethane, making measurements in the spectral range from 931.8 to 1252.3 cm(-1) for lecithin and from 911.4 to 1246.9 cm(-1) and 1695.3 to 1774.5 cm(-1) for soybean oil. Seven products from the Spanish market with lecithin concentrations between 21.1% and 99.1% and soybean oil concentrations between 0% and 37.2% were analyzed by the proposed method and the data was compared to a chromatograp…
Flow injection-spectrophotometric determination of metoclopramide hydrochloride.
1997
Abstract The determination of metoclopramide hydrochloride is spectrophotometrically determined by the Bratton-Marshall method in a flow injection assembly. The required nitrite is prepared on-line in the flow assembly by reducing a nitrate solution with the aid of a copperised cadmium solid-phase reactor. The calibration graph is linear over the range 0.5–85 mg l−1, with a relative standard deviation (RSD) of 0.89%, and sample throughput of 51 samples h−1. The method is easy and simple, and it is applied to determination of metoclopramide in some pharmaceutical formulations. The method eliminates the need for frequent preparation of unstable nitrite solutions.
Spectrophotometric determination of nalidixic and pipemidic acids in a flow injection assembly with a solid-phase reactor as a highly stable reagent …
2001
Abstract The flow-injection spectrophotometric determination of nalidixic (I) and pipemidic (II) acids were carried out by reaction with Fe(III) ions entrapped in a polymeric material and filling a packed-bed reactor; the released Fe(III) complexed with the quinolone is monitored at 426 nm. The method worked with a high reproducibility, even when using different reactors, days and solutions. Selectivity of the procedure was tested with different foreign compounds found in human urine as well as in pharmaceutical formulations containing both quinolones; no relevant interferences were observed. The calibration graph for (I) was linear over the range 1–250 μg ml −1 with a relative standard dev…
Calorimetric and structural investigation of the interaction between bovine serum albumin and high molecular weight dextran in water.
2005
This work studies specific interactions between a small globular protein and a highly flexible, branched polysaccharide using differential scanning calorimetry (DSC), circular dichroism (CD), fluorescence, and turbidimetry measurements. It uses the system water/bovine serum albumin (BSA)/dextran (D 2000) as a model. Dextran molecules are able to form interpolymeric complexes with BSA in water at both low and high temperatures if the polysaccharide is in excess and if the protein exists in its associated state. It leads to a partial destabilization of the secondary and tertiary structures of the protein and an additional exposure of the hydrophobic tryptophan residues to the surface of globu…
Local minimizers and gamma-convergence for nonlocal perimeters in Carnot groups
2020
We prove the local minimality of halfspaces in Carnot groups for a class of nonlocal functionals usually addressed as nonlocal perimeters. Moreover, in a class of Carnot groups in which the De Giorgi's rectifiability Theorem holds, we provide a lower bound for the $\Gamma$-liminf of the rescaled energy in terms of the horizontal perimeter.
Development and validation of a micellar liquid chromatographic method to determine three antitumorals in plasma
2017
Aim: A micellar liquid chromatographic method to determine several anticancer drugs (pazopanib, dabrafenib and regorafenib) in plasma was developed and validated by the guidelines of the EMA. Experimental: Plasma samples were directly injected, after a 1/5-dilution in a micellar solution. The drugs were resolved in <18 min using a C18 column. The mobile phase was an aqueous solution of 0.12 M SDS – 2% 1-pentanol, buffered at pH 7. The detection was performed by absorbance at 260 nm. Results: The values of the main validation parameters were: LOD (0.1–1 mg/l), calibration range (0.2–2 to 80 mg/l), accuracy (-12.5 to +11.7%) and precision (<11.9%). Conclusion: The procedure was conduct…
Furosemide assay in pharmaceuticals by Micellar liquid chromatography: study of the stability of the drug.
2000
A simplified high-performance liquid chromatographic procedure is described for the determination of furosemide (4-chloro-N-furfuryl-5-sulphamoylanthranillic acid), which makes use of UV detection, a C18, reversed-phase column, and micellar mobile phases of sodium dodecyl sulphate (SDS) and 1-propanol at pH 3 buffered with phosphate system. The most adequate experimental conditions to handle furosemide solutions in the analytical laboratory are studied. The mixture of furosemide and its degradation products which are formed upon light exposition was resolved with a mobile phase of 0.04 M SDS-2% propanol. Separation of furosemide from its common impurities and the hydrolytic product, 4-chlor…
TERMITE: AnRscript for fast reduction of laser ablation inductively coupled plasma mass spectrometry data and its application to trace element measur…
2017
RATIONALE High spatial resolution Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) determination of trace element concentrations is of great interest for geological and environmental studies. Data reduction is a very important aspect of LA-ICP-MS, and several commercial programs for handling LA-ICPMS trace element data are available. Each of these software packages has its specific advantages and disadvantages. METHODS Here we present TERMITE, an R script for the reduction of LA-ICPMS data, which can reduce both spot and line scan measurements. Several parameters can be adjusted by the user, who does not necessarily need prior knowledge in R. Currently, ten reference m…
Computational Modelling of Public Policy: Reflections on Practice
2018
Computational models are increasingly being used to assist in developing, implementing and evaluating public policy. This paper reports on the experience of the authors in designing and using computational models of public policy (‘policy models’, for short). The paper considers the role of computational models in policy making, and some of the challenges that need to be overcome if policy models are to make an effective contribution. It suggests that policy models can have an important place in the policy process because they could allow policy makers to experiment in a virtual world, and have many advantages compared with randomised control trials and policy pilots. The paper then summari…