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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.
Design of Bioresponsive Polymers
Published in Deepa H. Patel, Bioresponsive Polymers, 2020
Anita Patel, Jayvadan K. Patel, Deepa H. Patel
A quick system meant for the parting of oligomeric as well as polymeric moieties is GPC, also called size exclusion chromatography that is based upon the division of variations in molecular size in solution. For finding out the molecular weight distribution of synthetic polymers, GPC is an appropriate technique. With a view to find out the quantity of sample emerging, at the last part of the column a concentration detector is situated [69]. Furthermore, detectors possibly will be used to constantly find out the molecular weight of moieties eluting as of the column. An amount of solvent flow is as well observed to make available ways of distinguishing the molecular size of the eluting moieties. If required additional separation systems like high performance, liquid chromatography can be employed [69].
Mass Spectrometric Analysis
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Combined LC-MS should complement GC-MS by enabling the identification or quantitation of analytes that are either too labile or nonvolatile for gas chromatography. This is particularly desirable in veiw of the wide usage and advanced state of development of liquid chromatography. The major obstacle encountered in the development of LC-MS is the efficient transfer of solute to the mass spectrometer with minimal chromatographic solvent. This problem is compounded by the popular use of aqueous solvents and buffering salts used in the chromatography of polar solutes.
Stability of trastuzumab during nanomedicine formulation using SEC-HPLC coupled with polyacrylamide gel electrophoresis
Published in Pharmaceutical Development and Technology, 2023
Yu Gao, Andrew N. Shelling, David Porter, Euphemia Leung, Zimei Wu
The aim of this study was to assess the stability and degradation pathways of trastuzumab under various stress conditions including mechanical stress, repeated freeze-and-thaw, pH and temperature as well as measuring its long term storage stability. First, a simple and sensitive SEC high performance liquid chromatography (SEC-HPLC) method was developed and validated. F(ab)’ of trastuzumab was obtained by pepsin digestion followed by reduction with 2-mercaptoethylamine, and used to investigate the specificity of the SEC-HPLC method. Reconstituted lyophilised Herceptin (21 mg/ml in Water for Injection) and its dilutions (0.21 and 2.1 mg/ml) for clinical use were subjected to commonly applied experimental procedures during nanoparticle development; and the structural integrity after the stress conditions were investigated using the validated SEC-HPLC method along with SDS-PAGE. Lastly, the physicochemical stability of trastuzumab at −80 °C, 4 °C, 25 °C and 37 °C were assessed for up to 12 months using the two analytical methods; and the anti-proliferation stability of the solution stored at 4 °C based on the manufacturer’s recommendation for clinical settings was evaluated on a HER2 positive BT-474 breast cancer cell line. Compared with the existing reports (Kaiser and Kramer 2011; Pabari et al. 2011; Nalenz et al. 2018), trastuzumab was challenged to different pH, and covered a broader concentration range for an extended period of time in this study
Subacute oral toxicology and toxicokinetics of pterostilbene, a novel Top1/Tdp1 inhibiting anti-tumor reagent
Published in Drug and Chemical Toxicology, 2023
Changcheng Sun, Ying Li, Yutian Zhang, Haoyan Huang, Huili Chen, Jiaqin Chen, Luyao Han, Xiang Chen, Xijing Chen, Yongjie Zhang
A C18 column (150 × 2.0 mm, 2.1 µm, Shimadzu, Kyoto, Japan, VP-ODS) was used to analyze the plasma samples. Liquid chromatography was carried out using an ultra-high-performance liquid chromatography (UPLC) system (LC30A, Shimadzu, Kyoto, Japan). The isocratic elution was as performed by 80% water containing 5 mM ammonium acetate and 20% acetonitrile as mobile phase. The flow rate was maintained at 0.4 mL/min. UPLC was equipped with a triple quadrupole tandem mass spectrometer (AB Sciex 4000, Framingham, MA). Pterostilbene and chlorzoxazone (IS) were detected using negative mode and multiple reaction monitoring (MRM) with the transitions of m/z 255.10 → 240.10 and 168.0 → 132.1, respectively. Data processing and system control was performed with the analysis software version 1.6.3 (AB Sciex, Framingham, MA).
Accuracy of substance exposure history in patients attending emergency departments after substance misuse; a comparison with biological sample analysis
Published in Clinical Toxicology, 2023
Ishita Virmani, Alberto Oteo, Michael Dunn, Daniel Vidler, Clair Roper, Jane Officer, Gareth Hardy, Paul I. Dargan, Michael Eddleston, Jamie G. Cooper, Simon L. Hill, Rebecca Macfarlane, Liza Keating, Mark Haden, Simon Hudson, Simon H. L. Thomas
Toxicity resulting from substance misuse (sometimes called recreational drug use/misuse) is a common reason for emergency department (ED) presentations and hospital admissions [1,2]. Knowledge of the substances involved helps to interpret clinical features, anticipate the predicted clinical course, and inform appropriate monitoring and management decisions, including in some cases the administration of antidotes. Urine drug screening using immunoassays is sometimes performed, but has substantial limitations, including low sensitivity and specificity and, in particular, may not detect new psychoactive substances (NPS) [3], although methods have been developed to detect some specific compounds [4]. While liquid chromatography-mass spectrometry can be very sensitive for detecting substances of misuse, it is time consuming and expensive to perform. As a result, real-time analytical information is rarely available at the time of presentation, so the history provided by the patient or other witnesses is often the only source of information on substances involved. Research and surveillance studies of reported substance use, important for developing national drug control policies [5], may also rely on unvalidated user accounts for exposure information.