Publications by authors named "Mark Brader"
Preservation of the integrity of macromolecular higher-order structure is a tenet central to achieving biologic drug and vaccine product stability toward manufacturing, distribution, storage, handling, and administration. Given that mRNA lipid nanoparticles (mRNA-LNPs) are held together by an intricate ensemble of weak forces, there are some intriguing parallels to biologic drugs, at least at first glance. However, mRNA vaccines are not without unique formulation and stabilization challenges derived from the instability of unmodified mRNA and its limited history as a drug or vaccine.
View Article and Find Full Text PDFUnderstanding the structure of messenger RNA (mRNA) lipid nanoparticles, and specifically the microenvironment of the mRNA molecules within these entities, is fundamental to advancing their biomedical potential. Here, we show that a permeating cationic dye, thionine, can serve as a cryogenic electron microscopy contrasting agent by binding selectively to encapsulated mRNA without disturbing lipid nanoparticle morphology. Cryo-electron microscopy images identify the mRNA location, revealing that mRNA may exist within solvent-filled cavities or may be substantially lipid associated.
View Article and Find Full Text PDFEvery major biopharmaceutical company incorporates a protein crystallography unit that is central to its structure-based drug discovery efforts. Yet these capabilities are rarely leveraged toward the formal higher order structural characterization that is so challenging but integral to large-scale biologics manufacturing. Although the biotech industry laments the shortcomings of its favored biophysical techniques, x-ray crystallography is not even considered for drug development.
View Article and Find Full Text PDFThe evaluation of stability with respect to particles in prefilled syringes is complicated by the presence of silicone oil. The mobility, colloidal characteristics, and kinetic instability of silicone oil in contact with a protein formulation may be influenced in unpredictable ways by pharmaceutical variables, storage, and handling conditions. To provide insight into the impact of these variables on silicone oil originating specifically from the siliconized prefillable syringe (PFS), a series of studies were conducted at incremental syringe barrel siliconization levels.
View Article and Find Full Text PDFEvaluating prospective protein pharmaceutical stability from accelerated screening is a critical challenge in biotherapeutic discovery and development. Measurements of protein unfolding transitions are widely employed for comparing candidate molecules and formulations; however, the interrelationships between intrinsic protein conformational stability and pharmaceutical robustness are complex and thermal unfolding measurements can be misleading. Beyond the discovery phase of drug development, astute formulation design is one of the most crucial factors enabling the protein to resist damage to its higher order structure-initially from bioprocessing stresses, then from stresses encountered during its journey from the product manufacturing site to the bloodstream of the patient.
View Article and Find Full Text PDFScreening for pharmaceutically viable stability from measurements of thermally induced protein unfolding and short-term accelerated stress underpins much molecule design, selection, and formulation in the pharmaceutical biotechnology industry. However, the interrelationships among intrinsic protein conformational stability, thermal denaturation, and pharmaceutical stability are complex. There are few publications in which predictions from thermal unfolding-based screening methods are examined together with pharmaceutically relevant long-term storage stability performance.
View Article and Find Full Text PDFA simultaneous multiple sample light scattering (SMSLS) prototype instrument was built to simultaneously measure light scattering from many independent monoclonal antibody (mAb) solutions in order to monitor their time-dependent aggregation behavior and to characterize, via absolute Rayleigh scattering ratios, their molecular masses and second, third, and fourth virial coefficients under non-aggregating conditions at concentrations up to 190mg/ml. One stable mAb and another prone to aggregation were studied. Early phase aggregation rates spanned six orders of magnitude over temperatures 30 to 83°C for both mAbs and divided into "Arrhenius" and "Stochastic" regimes.
View Article and Find Full Text PDFWe present evidence that homogeneous submicron particles can influence the growth rate of larger particles upon long-term storage in a temperature-dependent manner. Interferon-beta-1a was thermally stressed at 50°C for 6 h and characterized using nanoparticle tracking analysis (NTA), microflow digital imaging (MFI), and circular dichroism (CD) spectroscopy. This study showed selective formation of submicron particles exhibiting a perturbed protein conformation.
View Article and Find Full Text PDFThere is significant scope for more meaningful evaluation of higher-order structure in defining the quality of biopharmaceutical products [Bush L. 2010. Biopharm Int 23(4):14].
View Article and Find Full Text PDFMonoclonal antibody (mAb) fragmentation can be a widespread problem across the biotechnology industry and there is a current need to better understand the underlying principles. Here, we report an example of a high-purity human IgG1 mAb prepared from CHO cells exhibiting fragmentation that can be attributed to residual proteolytic enzyme activity. The concomitant occurrence of proteolytic and non-proteolytic peptide bond cleavage is shown and the respective fragmentation patterns characterized using high-resolution LC-MS.
View Article and Find Full Text PDFSize-exclusion high-performance liquid chromatography (SE-HPLC, SEC) is the long-standing biopharmaceutical industry standard for quantitation of soluble protein aggregates. Recently, sedimentation velocity analytical ultracentrifugation (SV-AUC) has emerged as a possible orthogonal technique to SEC for soluble aggregate quantitation. Moreover, asymmetrical flow field flow fractionation (AF4) has shown early promise in quantifying protein aggregates, both soluble and insoluble.
View Article and Find Full Text PDFLY307161 is a 31 amino acid analog of glucagonlike peptide-1(7-37)OH susceptible to physical instability associated with pharmaceutical processing. Orthogonal biophysical studies were conducted to explore the origins of this physical instability and to distinguish pharmaceutically desirable states of this aggregating peptide from undesirable ones. Equilibrium sedimentation analysis established that LY307161 exists as a monomer at pH 3, and reversibly self-associates in the pH range 7.
View Article and Find Full Text PDFA series of Cu(II) and Cu(I)/Cu(II) complexes containing the cis-N(amine)(2)S(thiolate)(2) copper complex rac-2 has been synthesized to provide a basis for understanding the charge-transfer spectra of mixed-valence thiolate-bridged Cu(I)/Cu(II) complexes. In combination with Cu(Me(2)-13-N(4)ane), rac-2 yields a monobridged dinuclear homovalent adduct, rac-5, while reaction with CuCl yields the mixed-valance pentanuclear complex rac-6. In the presence of Cu(II)(acac)(2), chiral R,R-1 reacts to form a mixed-valence pentanuclear cation R,R-7.
View Article and Find Full Text PDFThe ability to tailor the release profile of a drug by manipulating its formulation matrix offers important therapeutic advantages. We show here that human insulin can be cocrystallized at preselected ratios with the fully active lipophilically modified insulin derivative octanoyl-N(epsilon)-LysB29-human insulin (C8-HI). The cocrystal is analogous to the NPH (neutral protamine Hagedorn) crystalline complex formed with human insulin, which is commonly used as the long-acting insulin component of diabetes therapy.
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