Publications by authors named "Grant E Frahm"

Article Synopsis
  • The development of stable reference standards for nanoparticle sizing is essential for consistent cross-laboratory studies and methodology transfer.
  • During the study, no significant changes in particle size were observed when reconstituting cross-linked albumin nanoparticles from a lyophilized state, whether they contained dodecanoic acid or not.
  • Stability over six months at -80 °C was confirmed through various analyses, showcasing the reproducibility of the reconstitution process across different technicians and labs.
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Product excipients are used to confer a number of desirable properties on the drug substance to maintain or improve stability and facilitate drug delivery. This is especially important for products where the active pharmaceutical ingredient (API) is a recombinant protein. In this study, we aimed to determine if excipients and formulation conditions affect the structure and/or modulate the dynamics of the protein API of filgrastim products.

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We have previously identified extensive glycation, bound fatty acids and increased quantities of protein aggregates in commercially available recombinant HSA (rHSA) expressed in Oryza sativa (Asian rice) (OsrHSA) when compared to rHSA from other expression systems. We propose these differences may alter some attributes of nanoparticles fabricated with OsrHSA, as studies have associated greater quantities of aggregates with increased nanoparticle diameters. To determine if this is the case, nanoparticles were fabricated with OsrHSA from various suppliers using ethanol desolvation and subsequent glutaraldehyde cross-linking.

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Microflow digital imaging (MDI) has become a widely accepted method for assessing sub-visible particles in pharmaceutical formulations however, to date; no data have been presented on the utility of this methodology when formulations include opaque vaccine adjuvants. This study evaluates the ability of MDI to assess sub-visible particles under these conditions. A Fluid Imaging Technologies Inc.

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Human serum albumin (HSA) is a versatile and important protein for the pharmaceutical industry (Fanali et al., Mol. Aspects Med.

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Article Synopsis
  • Different expression systems for producing recombinant human proteins can lead to significant variability in chemical modifications, affecting their structure, stability, and immunogenicity, especially in plant-based systems.
  • Studies on recombinant human serum albumins (rHSA) produced in Asian rice showed extensive characterization compared to plasma-derived and yeast-expressed albumins, revealing concerns about heterogeneity and high molecular weight aggregates.
  • Analysis techniques such as LC-MS and circular dichroism indicated higher glycation levels and structural changes in rHSA from rice, highlighting supplier and lot variations that could impact product quality.
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Context: At elevated temperatures, studies have shown that serum albumin undergoes irreversible changes to its secondary structure. Anionic fatty acids and/or anionic surfactants have been shown to stabilize human serum albumin (HSA) against thermal denaturation through bridging hydrophobic domains and cationic amino acids residues of the protein.

Objective: As albumin can readily interact with a variety of liposomes, this study proposes that cardiolipin delivered via 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes can improve the thermal stability of recombinant HSA produced in Saccharomyces cerevisiae (ScrHSA) in a similar manner to anionic fatty acids.

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Previous studies have demonstrated that liposome-protein interactions can result in changes to the thermal stability of the protein. We utilized far-UV circular dichroism spectropolarimetry and fluorescence spectroscopy to investigate the interaction of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes with two recombinant human serum albumins (rHSA). We demonstrate that rHSA expressed in Oryza sativa (OsrHSA) has improved secondary structure thermal stability compared to rHSA expressed in Pichia pastoris (PprHSA).

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