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Drug Substance and Excipient Characterization
Published in Dilip M. Parikh, Handbook of Pharmaceutical Granulation Technology, 2021
Parind M. Desai, Lai Wah Chan, Paul Wan Sia Heng
In liquid chromatography, the affinity of the material for the solid stationary phase in a column governs the time taken by the material to elute from the column. The time of elution is used to identify the material. Solutions of the drug, excipient, and drug–excipient mixture are prepared and injected separately into the column. The concentration of the material that elutes from the column is detected and plotted against time to give a chromatogram. If there is interaction between the drug and excipient, the complex formed will exhibit an elution time different from those of the individual components (Figure 3.14). Similarly, gas chromatography may be used for volatile components.
Gas Chromatographic Analysis
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Gas chromatography, by definition, includes those separations that involve gas as the mobile phase. Two primary categories are gas-solid chromatography and gas-liquid chromatography (GLC), which involve solids or liquids, respectively, as stationary phases packed in columns. In the former case, the analyte is adsorbed by the solid, and in the latter the analyte dissolves in the stationary liquid. The volatility of the analyte effects partitioning as more gas is passed along the column. The preponderance of GC methods involving antibiotics are by GLC.
Adulteration of Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Gas chromatography is one of the most widely deployed methods in analytical chemistry to investigate organic sample material due to its simple ease of use, the ready availability of sophisticated inexpensive instrumentation, and the large amount of qualitative and quantitative information that can be retrieved if the appropriate configuration is employed. Especially the high separation efficiency for volatiles makes GC very suitable to investigate complex mixtures and sample matrices. But for some applications, the separation performance is not sufficient when it comes to very complex mixtures like odors, flavors, crude oil products, and foodstuff. Co-elution with other analytes or sample matrix elements causes problems in detection and quantitation especially when the analytes differ greatly in their concentration. This problem can be solved by cutting out the co-eluting part of the chromatogram and a subsequent second chromatographic separation of the excised effluent preferably on a stationary phase of different polarity. This technique, called heart-cutting or two-dimensional GC (2D GC or GC-GC), is done with the help of a diverting valve or a Deans switch. The sought-after substances are then resolved in the second GC column.
Tea extracts differentially inhibit Streptococcus mutans and Streptococcus sobrinus biofilm colonization depending on the steeping temperature
Published in Biofouling, 2020
Mi-Ah Kim, Jae-Hwan Kim, Ok Hyung Nam
To determine the phytochemical profiles, tea extracts with different steeping temperatures were subjected to GC-MC analysis as previously described with modification (Gressler et al. 2012). The methanol extract sample was processed by speed vacuum and derivatization with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA; Sigma Aldrich, St Louis, MO, USA). GC-MS analysis was performed using a QP2010 gas chromatograph coupled with a mass spectrometer (Shimadzu, Milan, Italy) at an electron ionization voltage of 70 eV. Gas chromatography was conducted in the temperature-programmed mode with a Restek column (0.25 mm, 30 m; XTI-5). The initial column temperature was set at 70 °C for 3 min with increased linearly at 10 °C/min up to 300 °C, and then the temperature was held for 5 min. The temperature of the injection port was 280 °C, and the GC/MS interface was maintained at 290 °C. The helium carrier gas flow rate was 1.0 ml min−1.
Using online content uniformity measurements for rapid automated process development exemplified via an X-ray system
Published in Pharmaceutical Development and Technology, 2019
Bernhard Wagner, Thomas Brinz, Johannes Khinast
Machines for the online gravimetric weighing are commercially available from several manufactures and can detect the capsule weight within the RAPD concept. Compared to this, a CU check requires much more effort and equipment. On the one hand, there are the analytical techniques like for example HPLC (high performance liquid chromatography), TLC (thin layer chromatography), or GC (gas chromatography). These techniques require an elaborated sample preparation before the content can be determined. The measurements take a certain time and the content cannot be measured in-line within the capsule production. Thus, an integration into the RAPD would be challenging, as a requirement is a fast measurement of the samples in an automated way. Possibly, the measurements can be automated (e.g. Saitoh and Yoshimori 2008) or executed offline. However, significant time and effort is required.
Chemical composition, anti-toxoplasma, cytotoxicity, antioxidant, and anti-inflammatory potentials of Cola gigantea seed oil
Published in Pharmaceutical Biology, 2019
O. Atolani, H. Oguntoye, E. T. Areh, O. S. Adeyemi, L. Kambizi
Chromatographic separation of the compounds was performed on a gas chromatograph. Aliquot (1 µL) of the sample was injected into an Agilent 6890 N (Agilent, Palo Alto, CA) coupled to an Agilent 5975 MS mass spectrometer detector, using a Zebron AB-MultiResidue II (30 by 0.25 mm ID, 0.25 µm film thickness) column (Part No. 7HG-G016-11). The oven temperature program was maintained at 100 °C for 2 min, ramped at 15 °C/min to 180 °C held for 0 min, ramped at 5 °C/min to 250 and held for 3 min and finally at 20 °C/min to 320 °C held for 12 min. The total run time was 40 min. The carrier gas was helium at a flow rate of 1.2 mL/min and the injector temperature was maintained at 200 °C and operated in a splitless mode. The Mass spectral data were recorded on a MSD operated in full scan mode (35–600 m/z) with both the ion source and quadruple temperatures maintained at 240 °C and 150 °C, respectively. The transfer line temperature was maintained at 200 °C. Solvent Delay was held at 5.00 min. The compounds were identified on the basis of fragment pattern obtained and comparison of the retention time with that of authentic samples injected.