Search

Introduction: PF-06439535 (bevacizumab-bvzr; Zirabev®) is a bevacizumab biosimilar. The stability profile and functional activity of PF-06439535 after dilution for intravenous infusion was evaluated following extended storage conditions. Methods: PF-06439535 drug product was diluted in 0.9% sodium chloride to produce final concentrations of 1.4 and 16.5 mg/mL of PF-06439535, representing clinically relevant low and high doses for intravenous infusion. Three drug product lots and three infusion bag types (polyolefin, ethylene vinyl acetate, and polyvinyl chloride) were tested. To simulate the potential preparation and administration conditions encountered in a clinical setting, prepared drug solutions were initially stored at 25 ± 5°C for 24 ± 2 h, and then at 5 ± 3°C for up to 6 weeks. Extended storage was followed by storage at 25 ± 5°C for 24 ± 2 h before testing. Physicochemical and biological stability were evaluated according to visual characteristics and pH, protein concentration, particulate content, the proportions of molecular weight variants and charge variants, and relative potency. A wide range of analytical techniques optimized for PF-06439535 assessment were employed, such as size-exclusion chromatography, non-reducing sodium dodecyl sulfate capillary electrophoresis, cation-exchange chromatography, far-UV circular dichroism spectroscopy, differential scanning calorimetry, and an in vitro cell-based bioassay. Results: For all concentrations, drug product lots, infusion bag types, and time points tested, there were no significant changes in protein concentration and no notable differences in visual characteristics (color, clarity, and visible particulates). The abundance of molecular weight variants and charge variants remained stable over the 6-week study period. There were no stability concerns with regard to sub-visible particles. There were no significant changes in primary, secondary, or tertiary structure. Finally, the in vitro relative potency of PF-06439535 was maintained throughout the study period. Conclusions: The stability and biological activity of PF-06439535 was maintained after dilution and storage for up to 6 weeks at 2–8°C, demonstrating the integrity of diluted PF-06439535 under extended in-use conditions. [ABSTRACT FROM AUTHOR]

Introduction: The stability and functional activity of the trastuzumab biosimilar PF-05280014 (trastuzumab-qyyp; TrazimeraTM), was assessed under extended in-use conditions. Methods: PF-05280014 was diluted in 0.9% sodium chloride to final concentrations of 0.2 mg/mL and 4 mg/mL in 3 different types of infusion bags (polyolefin, ethylene vinyl acetate, and polyvinyl chloride). Infusion bags containing diluted PF-05280014 were stored at 25 ± 5° C for 24 h, before storage at 5 ± 3° C for 0, 1, 2, 4, or 6 weeks. Following extended storage, samples of PF-05280014 were removed from the infusion bags and stored at 25 ± 5° C for 24 h before biophysical and functional characterization. In addition to the visual characteristics of each sample at the various time points, the stability of PF-05280014 was assessed using a variety of biophysical techniques, including size-exclusion high-performance liquid chromatography, non-reducing sodium dodecyl sulfate capillary electrophoresis, cation-exchange chromatography, peptide mapping, far-UV circular dichroism spectroscopy, and differential scanning calorimetry. The functional activity of PF-05280014 was evaluated using a cell-based growth inhibition assay. Results: For all PF-05280014 concentrations, time points and infusion bags tested, there were no significant differences in visual characteristics or in protein concentration. The were no significant changes in the relative abundance of molecular weight or charge variants throughout the 6-week study period. Similarly, there were no significant changes in primary structure or in secondary structure content during the study. The relative potency of PF-05280014 was also maintained throughout the 6-week period. Conclusions: The stability and functional activity of PF-05280014 was maintained following dilution in 0.9% sodium chloride and storage for up to 6 weeks at 2–8° C. [ABSTRACT FROM AUTHOR]

RAMPED-UP NMR method is presented which generates simple spectra, which are easy to interpret, and allows several proteins to be screened simultaneously. The ability of three different proteins to be analyzed simultaneously for binding to two different ligands is demonstrated.

The drug discovery process relies on characterizing structure-activity relationships, since specific ligand-target interactions often result in important biological functions. Measuring diffusion coefficients by nuclear magnetic resonance spectroscopy is a useful way to study binding, because changes can be detected when a small ligand interacts with a macromolecular target. Diffusion coefficients can be miscalculated, however, due to magnetization transfer between the receptor and ligand. This transferred nuclear Overhauser effect (trNOE) disrupts the observed signal decay due to diffusion as a function of the experimental diffusion time. Since longer diffusion times also selectively edit free ligand signal, the measured diffusion coefficients become biased toward the fraction of bound ligand. Despite this discrepancy, under these experimental conditions, the trNOE selectively influences the measured signals of binding ligands and can be used to gain insight into ligand-protein interactions. These phenomena have been studied for caffeine and L-tryptophan, which bind to human serum albumin, and the antimalarial agent trimethoprim, which interacts with dihydrofolate reductase. The results provide insight into the nature of ligand-protein binding and are thus useful for elucidating the molecular features of the ligand that interact with the protein.

Results reveal that the hydrogen bond network contributed by the first 15 amino acid residues of aporubredoxin or their interaction with other parts of the protein confer thermostability to the bacterial apo- and holoaporubredoxins.

A complete relative stereochemistry of an organic molecule with five stereocenters is determined by the use of Residual Dipolar Couplings (RDCs) in combination with molecular order matrix calculations. The stereochdmical assignments of the stereocenters obtained by using only RDC is in perfect agreement with the X-ray crystallographic study.

Research has been conducted on six-membered chairlike rings. The method developed for determination of the relative structure elements in these rings is described.

Diffusion-based NMR techniques are widely used in the pharmaceutical industry for a variety of methods like screening of chemical mixtures or determining the structures of bound ligands without physical separation. Diffusion deviation is a good method for characterization of the ligand isotope and to build epitope map diffusion, data was collected with a long diffusion time.

Residual dipolar couplings (RDCs), induced by aligned cosolutes, have revolutionized biomolecular three-dimensional structures prediction, which has led to the development of different methods of predicting alignment tensors making RDCs easier to interpret. Studies are conducted to create a different approach to derive an expression for the alignment tensor induced by a neutral as well as a dilute cosolute.