Contribution of Intravenous Administration Components to Subvisible and Submicron Particles Present in Administered Drug Product.

Particulate matter present in drug products intended for parenteral administration to patients is typically monitored and controlled in the finished drug product to minimize potential risks to patients. In contrast to particulates found in drug products, the current study evaluated particulates representative of materials and operations typically used in the dose preparation and administration of drug products. A comprehensive assessment of intrinsic and extrinsic sources of subvisible and submicron particulates arising from materials associated with subcutaneous and intravenous dose preparation and administration was conducted. In particular, particles arising from disposable syringes, commercial sterile diluents, and intravenous supplies were quantitated using established methods for subvisible (light obscuration, flow imaging) and submicron particles (resistive pulse sensing). Each of these sources contributed varying amounts of particulates; therefore, owing to sources from materials required for administration, it is inadequate to assume that the total particulate load delivered to patients arises solely from the drug product. Careful consideration of the administration method and supplies used can improve the predictability of particulate levels present in dose preparations or administration volumes.

Quantification and characterization of subvisible proteinaceous particles in opalescent mAb formulations using micro-flow imaging.

Micro-flow imaging (MFI) has been shown to be more sensitive than light obscuration (LO) methods for measuring subvisible proteinaceous particles in protein formulations. Given the potential challenges in detecting particulates in opalescent mAb formulations, the accuracy of MFI to size and count particles in opalescent solutions was investigated and compared to LO and membrane microscopy methods. Proteinaceous monoclonal antibody (mAb) particles, generated either by chemical denaturation or agitation stress, polystyrene and glass particles were used as model systems for measurements in opalescent mAb solutions. The sizing and counting accuracies of MFI were unaffected by the opalescence of the medium. Using glass particles as a model system for proteinaceous particles, MFI was able to detect relatively low particle concentrations (approximately 10/mL) in opalescent solutions. MFI showed excellent linearity (R(2) = 0.9969) for quantifying proteinaceous particles in opalescent solutions over a wide range of particle concentrations (approximately 20-160,000/mL). Analyses of MFI particle image intensities revealed significant differences in the transparency of proteinaceous particles as a function of their size and mode of generation. LO method significantly underestimated proteinaceous particles, particularly those in the 2-10 microm size range. The less opaque proteinaceous particles were relatively more underestimated by the LO method in opalescent solutions.

A new scaleable freeze-thaw technology for bulk protein solutions.

A new method of freeze-thaw is described using experimental data obtained from freezing of purified rhGH (recombinant human growth hormone). The method is based on freezing protein solutions in rectangular rather than cylindrical containers. It is hypothesized that the change in container geometry allows for linear scale-up of the freeze-thaw operation based on equivalency of temperature-time profile. The hypothesis is tested using freeze-thaw data from a miniature (30 ml) and a 2.4 litre container. Computational fluid dynamics techniques are used to simulate the freeze process and the simulations are compared with experimental results. Protein quality is assessed as a function of freeze conditions using dynamic light scattering, circular CD, size-exclusion and reverse-phase HPLC measurements. The results demonstrate the applicability of the new approach. Freezing of rhGH solution at concentrations of approx. 30 mg/ml is shown to be possible with no damage to the molecule for up to five cycles of freeze-thaw. A nitrogen blast chest-freezer is designed and evaluated as part of the process. The refrigeration system and the freeze-thaw method can be used to freeze-thaw bulk protein solutions for development work and has the potential for transfer to manufacturing.

Biophysical signatures of noncovalent aggregates formed by a glucagonlike peptide-1 analog: a prototypical example of biopharmaceutical aggregation.

LY307161 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 7.5-10.5. Causative factors for physical instability related to lyophilization conditions were investigated. Solution pH, acetonitrile content, and concentration of the peptide prior to lyophilization each impacted physicochemical properties of the resultant powders. A comparative study of two powder samples exhibiting physicochemically disparate properties established that LY307161 forms soluble noncovalent aggregates. FT-IR analyses in the solid and solution states identified a prominent band at 1657-1659 cm(-1) attributed to alpha-helix structure. Noncovalent soluble aggregate exhibited characteristic bands at 1615 and 1698 cm(-1) indicative of intermolecular beta-sheet structure. An agitation-induced, precipitated solid form of LY307161 exhibited a different FT-IR signature indicative of a conformationally distinct species. Circular dichroism and fluorescence spectroscopy, together with dynamic light scattering measurements and dye-aggregate complexation, provided additional insights into the distinctions between aggregated and native LY307161.