Author Archives: Douglas Nesta

Aggregation from Shear Stress and Surface Interaction: Molecule-Specific or Universal Phenomenon?

Exposure to solid–liquid and air–water interfaces during production, freezing and thawing, shipment and storage of protein therapeutics may be a contributing factor in their degradation (e.g., aggregation, fragmentation) (1, 2). Surface exposure, particularly during manufacturing processes, often is accompanied by various degrees and durations of shear stresses originating from fluid flow and acting on proteins at interfaces. The magnitude and duration of shear rates depends on velocity gradients within each solution and varies significantly among manufacturing steps. On the low…

Evaluating Freeze–Thaw Processes in Biopharmaceutical Development – Small-Scale Study Designs

Regulations mandate that biopharmaceutical product quality be controlled throughout manufacturing, storage, transportation, and delivery to patients (1). Operations often include freezing and thawing of a bulk drug substance, dilution of that purified substance to a target concentration, filtration, filling into a selected container–closure system, additional processing (e.g., lyophilization), inspection, packaging, storage, transport, and delivery (2). Freezing is a common processing step used to maintain stability and quality of a drug substance during development and production of biopharmaceutical products. It is…

Formulation Effects on Opalescence of a High-Concentration MAb

    Monoclonal antibodies (MAbs) are increasingly formulated at concentrations >100 mg/mL as a means to deliver a high dose in a low volume (1,2). Such high-concentration solutions are commonly opalescent (3,4), an undesirable characteristic of biopharmaceutical products for several reasons. Although it may be only aesthetic, opalescent products are not considered pharmaceutically “elegant.” Of more serious concern, opalescence may be a precursor to aggregation and indicate a propensity toward decreased product stability or quality. The term opalescent refers to…