Authors:Rui Macêdo, Antonio Gouveia de Souza, Ana Miriam, and Carvalho Macêdo
A study was made of the thermal behavior of the starting materials, their mixtures and the resulting mebendazole tablets.
The thermal curves were obtained with a Shimadzu thermobalance, model TGA-50, using an air flow of 50 mL min−1 and a heating rate of 10°C min−1 in the temperature interval 30–900°C. The reaction constant velocities for the mebendazole salt and tablets were determined
isothermally, using the Arrhenius expression. The thermal stability of mebendazole tablets is lower than that of the mebendazole
salt, due to the presence of starch and lactose in the composition. Analysis of the data reveals that thermogravimetry is
a powerful tool in pharmaceutical technology and quality control.
Authors:R.-R. Durón, L. C. Almaguer, A. De J. Garza-Juárez, Ma. De La Luz, Salazar Cavazos, and N. Waksman-De-Torres
Use of thin-layer chromatography (TLC) for quality control of herbal medicinal products (HMPs) is very useful for determining and comparing the compositions of such products. In Mexico, HMPs are sold as herbal dietary supplements, and there is no legislation regarding their quality control. Heterotheca inuloides, Citrus aurantium, Peumus boldus, Equisetum arvense, Eucalyptus globulus, Ginkgo biloba, Mentha piperita, Aloe vera, Salvia officinalis, and Cassia senna are some of the major commercial products obtained from plants in this region. In this paper we describe the effectiveness of TLC methods for quality control of several commercial products containing plants and their extracts. We used one or several specific markers for each type of plant. In only 20% of the 40 commercial products that were analysed did the chromatographic characteristics of the respective plants match those of the specific respective marker compounds. These results highlighted a problem arising from the lack of regulation of these products. The proposed TLC methods are simple, sensitive, and specific, and can be used for routine quality control of raw herbal products and formulations of the plants tested. The results obtained emphasize the need to develop simple and reliable analytical methods that can be performed in any laboratory for the purpose of quality control of dietary supplements or commercial herbal products sold in Mexico.
Authors:E. Pączkowska, D. Smukowska, E. Tratkiewicz, and P. Białasiewicz
A simple and accurate reversed phase high-performance liquid chromatography (HPLC) method has been developed for the estimation of uniformity of dosage units, and delivered dose uniformity tests of fluticasone propionate and salmeterol xinafoate in samples obtained during the fine particle mass determination, using C8 Luna (2) 100A 100 × 4.6 mm, 5 micrometer particle size in gradient mode, with mobile phase comprising of buffer solution: 0.6% trifluoroacetic acid solution in water-tetrahydrofurane (8:2 v/v) and acetonitrile-methanol (1:1 v/v) in the ratio of 60:40 v/v. The flow rate was 1.5 mL min−1, and the detection was monitored by ultraviolet (UV) detector at 239 nm and 250 nm. Linearity was observed in the concentration range of 0.025–4.8 μg mL−1 for salmeterol xinafoate and 0.04–32.5 μg mL−1 for fluticasone propionate (R2 > 0.999). The recovery in the range from 98.2% to 102.7% and relative standard deviation (RSD) ≤ 2.2% demonstrated accuracy and high precision of the method. The quantification limit at an injection volume of 40 μL was 0.04 μg mL−1 for fluticasone propionate and 0.025 μg mL−1 for salmeterol xinafoate. The developed and validated method can be successfully applied for simultaneous quality control of dry powder inhalation products containing salmeterol xinafoate and fluticasone propionate in pharmaceutical industry.
Analytical quality control is needed to ascertain the reliability of results from all types of analysis, including activation analysis. Thea priori precision has to be combined with the statistics of counting in order to reach a state of statistical control. The Analysis of Precision is used to verify the absence of unknown sources of variability and to ascertain the absence of systematic biases or calibration errors by analyzing samples or reference materials with accurately known content or actual samples by an independent method.
Authors:X. Li, J. Xu, Y. Jiang, L. Chen, Y. Xu, and C. Pan
High-performance liquid chromatography with a hydrophilic-interaction liquid chromatographic (HILIC) column has been successfully used to retain and separate the polar phosphonic herbicides glyphosate and glufosinate. Online electrospray tandem ion-trap mass spectrometric and DAD detection were used. The effects on the separation of mobile phase acetonitrile content, buffer concentration, and flow rate, and of column temperature, were investigated. With UV-visible detection at 195 nm, LOQ were <850 mg kg−1, showing the method is suitable for product quality control of these herbicides alone or in combination. Tandem mass spectrometric conditions were optimized for ion-trap detection. Quantification was by use of selected reaction monitoring transitions m/z 168 → 150 in negative-ion mode for glyphosate and m/z 182 → 136 in positive-ion mode for glufosinate. Limits of detection (LOD; S/N > 3) were 0.20 and 0.16 ng for glyphosate and glufosinate, respectively, and the respective limits of quantification (LOQ; S/N = 10) were 0.02 and 0.05 mg kg−1. Sample derivatization was not necessary to achieve low detection limits in residue analysis in this study. Recovery from watermelon, spinach, potato, tomato, radish-root, and water fortified with the herbicides ranged from 63.6 to 107.3% and relative standard deviations were <15.3%.
Bioassay group of Indira Gandhi Centre for Atomic Research at Kalpakkam carries out routine surveillance of all radiation workers at the Centre by both whole-body counting and excreta analysis for assessing internal contamination. Various quality control measures adopted and experience gained in participating in inter-laboratory comparisons is highlighted.
Quality control, as applied in normal activation analysis by the simultaneous analysis of well-characterized quality control
samples, blanks and sometimes duplicates, cannot fully be applied in large sample analysis. Well characterized control samples
are, e.g., not available at the size of large samples. Different approaches have to be developed to monitor and to control
sources of errors in this new type of chemical analysis. Some of the measured sample parameters dealing with gamma-ray and
neutron attenuation can only vary between well known values of elemental constants. These parameters can much easier be determined
in large sample analysis than with samples in the milligram range, thus offering an outlook for direct verification of the
quality of the related correction algorithms. Some examples are given here from experience with the kg-scale neutron activation
analysis at the facilities in Delft.
A kit-like procedure is described for the labelling of Hippuran by exchange in a melt with carrier-free iodide-123 directly
formed from the decay of123Xe. Decay and subsequent melting for 15 min at 180°C are performed in one and the same ampoule. This results in a transfer
of 95% of the123I-activity into Hippuran with a residual123I-content of <1.0%. Quality control is based on thin-layer chromatography. Contaminants are discussed and a comparison is
made with commercial preparations of Hippuran-131I.