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Current Perspectives and Methods for the Characterization of Natural Medicines
Published in Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg, Promising Drug Molecules of Natural Origin, 2020
Muthusamy Ramesh, Arunachalam Muthuraman, Nallapilai Paramakrishnan, Balasubramanyam I. Vishwanathan
Chromatography is a major method for the separation of bioactive products from natural resources. This technique works based on the distribution of molecules in different phases. The natural compounds are distributed into two different phases, i.e. stationary phase and mobile phase. Based on the relative distribution of the chemical constituents, the constituents are separated. Chromatography is functioning by different methods: (i) column/adsorption chromatography; (ii) partition chromatography; (iii) paper chromatography; (iv) thin-layer chromatography; (v) gas-liquid chromatography; (vi) gas-solid chromatography; and (vii) ion-exchange chromatography. The parameters such as retention factor, selectivity, efficiency, retention time, and peak area are investigated for the structural characterization of marine products based on chromatography. Different types of chromatography techniques employed in the isolation and characterization of phytochemicals and marine constituents are tabulated in Table 2.1.
Standardization of Herbal Drugs
Published in Ravindra Kumar Pandey, Shiv Shankar Shukla, Amber Vyas, Vishal Jain, Parag Jain, Shailendra Saraf, Fingerprinting Analysis and Quality Control Methods of Herbal Medicines, 2018
Ravindra Kumar Pandey, Shiv Shankar Shukla, Amber Vyas, Vishal Jain, Parag Jain, Shailendra Saraf
Chromatography (mostly column and gas) is recommended as the principal method for the determination of pesticide residues; column and gas chromatography (GC) are most frequently used. These methods may be coupled with mass spectrometry (MS). Impurities present in herbal drugs are removed by partition and/or adsorption chromatography, and individual pesticides are measured by GC, MS or GC-MS. WHO has laid down general limits for pesticide residues in medicine (De Smet, 1997; WHO, 1996, 1998).
Biological Applications of Total Internal Reflection Fluorescence
Published in R. Michael Gendreau, Spectroscopy in the Biomedical Sciences, 1986
Seth A. Darst, Channing R. Robertson
The interactions of macromolecules with solid surfaces are complex and not well characterized but are of considerable importance in a number of biological applications. For example, the first step in the complicated process of thrombogenesis, either on natural or foreign surfaces in contact with blood, is recognized to be the adsorption of plasma proteins.1–3 In addition, many laboratory analytical assays and separation techniques rely on the adsorption of proteins to solid surfaces. These include adsorption chromatography for the separation of proteins4 and immunoadsorbent assays.5 Furthermore, the surface diffusion of nonspecifically adsorbed macromolecules is thought to enhance binding with specific cell-surface receptors.6 Also, the interactions between macromolecules associated with cell membranes and solid surfaces or with other membranes are of obvious importance throughout the field of cellular biology. These are just a few selected instances where macromolecule/surface interactions play a predominant role.
In vitro and in silico assessment of the developability of a designed monoclonal antibody library
Published in mAbs, 2019
Adriana-Michelle Wolf Pérez, Pietro Sormanni, Jonathan Sonne Andersen, Laila Ismail Sakhnini, Ileana Rodriguez-Leon, Jais Rose Bjelke, Annette Juhl Gajhede, Leonardo De Maria, Daniel E. Otzen, Michele Vendruscolo, Nikolai Lorenzen
Early screening is further challenged by the quality and quantity of antibody candidates available at the early stages of development, which are commonly prepared in minute amounts, low concentrations and relatively low purity. These factors may cause large errors and issues of measurement reproducibility.10 Consequently, these screening methods do not attempt to directly measure properties such as solubility, aggregation and viscosity, but they rather aim to determine parameters that are easier to measure and considered to be predictive of these properties. For example, non-specific interactions of antibodies with polyclonal immunoglobulin G (IgG) antibodies assessed using cross-interaction chromatography (CIC) have been found to correlate with solubility16 and in vivo clearance rates.18 It has also been reported that the monomer-retention time in standup monolayer adsorption chromatography (SMAC) depends on the non-specific interaction of antibodies with the column matrix, and tends to correlate with antibody precipitation and aggregation,14 while estimates of the apparent hydrophobicity from hydrophobic interaction chromatography (HIC) correlate with aggregation10,13 and in vivo clearance.19 Furthermore, reversible self-association from affinity-capture self-interaction nanoparticle spectroscopy (AC-SINS) has been found to predict viscosity, solubility issues20–23 and in vivo clearance.15
Blueprint for antibody biologics developability
Published in mAbs, 2023
Carl Mieczkowski, Xuejin Zhang, Dana Lee, Khanh Nguyen, Wei Lv, Yanling Wang, Yue Zhang, Jackie Way, Jean-Michel Gries
Other more commonly used characterization tools, such as HIC, can assess hydrophobicity, which is commonly associated with nonspecific binding and overall “stickiness”.19 Other methods reported to assess potential nonspecific interactions are CIC and standup monolayer adsorption chromatography.187,188 If assays recently shown to be predictive of nonspecific interactions have not been implemented into a developability workflow, standard process and analytical approaches may offer clues. For example, the therapeutic molecule may bind nonspecifically to purification and analytical resins or possess high surface hydrophobicity revealed computationally or experimentally by HIC.34 This information can then be considered when deciding a lead.
An accelerated surface-mediated stress assay of antibody instability for developability studies
Published in mAbs, 2020
Marie R.G. Kopp, Adriana-Michelle Wolf Pérez, Marta Virginia Zucca, Umberto Capasso Palmiero, Brigitte Friedrichsen, Nikolai Lorenzen, Paolo Arosio
In addition to CIC, we applied stand-up monolayer adsorption chromatography (SMAC) and SMAC* to evaluate the nonspecific interactions of mAbs with different chromatographic surfaces.14,62 Retention times are inversely related to the colloidal stability of mAbs, meaning that mAbs prone to precipitation or aggregation exhibit longer retention times on the column. Of all developability assays, these two assays correlated the highest with the HNSSA (SMAC*: rp = 0.82, rs = 0.87; p ≤ 0.01, SMAC: rp = 0.89, rs = 0.90; p ≤ 0.01, Figure 5).