Functional integrity of intravenous immunoglobulin following irradiation with a virucidal dose of gamma radiation

Application of Formulation Principles to Stability Issues Encountered During Processing, Manufacturing, and Storage of Drug Substance and Drug Product Protein Therapeutics

The field of formulation and stabilization of protein therapeutics has become rather extensive. However, most of the focus has been on stabilization of the final drug product. Yet, proteins experience stress and degradation through the manufacturing process, starting with fermentaition. This review describes how formulation principles can be applied to stabilize biopharmaceutical proteins during bioprocessing and manufacturing, considering each unit operation involved in prepration of the drug substance. In addition, the impact of the container on stabilty is discussed as well.

Free radical studies of components of the extracellular matrix: contributions to protection of biomolecules and biomaterials from sterilising doses of ionising radiation

The purpose of the current review is show how the principles and techniques of radiation chemistry have enabled the direct reactions of free radicals with biomolecules and biomaterials to be investigated at the molecular level. In particular, the review focusses on the free radical-induced fragmentation of glycosaminoglycans. Glycosaminoglycans are large linear polysaccharides consisting of repeating disaccharide units and are important components of the extracellular matrix (ECM) either in free form (hyaluronan) or as a component of proteoglycans. Oxidative damage of the extracellular matrix components by either enzymatic or non-enzymatic pathways may have implications for the initiation and progression of a range of human diseases. These include arthritis, kidney disease, cardiovascular disease, lung disease, periodontal disease and chronic inflammation. Oxidative damage to hyaluronan by reactive oxidative species and thus the potential mechanism of damage to the ECM and its role in human pathologies is reviewed with particular focus on damage initiated by potential in vivo free radicals such as superoxide, carbonate and hydroxyl radicals. Such knowledge has also allowed radiation protecting systems to be developed so that sterilising doses of radiation can be delivered to sensitive biomolecules such as proteins and glycosaminoglycans, and also to sensitive biomaterials such as tissue allografts.

Recovery and purification process development for monoclonal antibody production

Hundreds of therapeutic monoclonal antibodies (mAbs) are currently in development, and many companies have multiple antibodies in their pipelines. Current methodology used in recovery processes for these molecules are reviewed here. Basic unit operations such as harvest, Protein A affinity chromatography, and additional polishing steps are surveyed. Alternative processes such as flocculation, precipitation, and membrane chromatography are discussed. We also cover platform approaches to purification methods development, use of high throughput screening methods, and offer a view on future developments in purification methodology as applied to mAbs.

Impact of irradiation and immunoglobulin G concentration on absorption of protein and immunoglobulin G in calves fed colostrum replacer

The objective of this study was first to evaluate whether irradiation treatment of a commercial colostrum replacer (CR) affected acquisition of passive immunity. If the irradiation treatment negatively affected the acquisition of passive immunity, the second objective was to evaluate whether an increased total IgG mass, in a single feeding of CR derived from bovine serum fractions, could compensate for this effect. Acquisition of passive immunity was assessed by 24-h serum IgG levels, serum protein levels, apparent efficiency of absorption (AEA) of IgG, and the ability to prevent failure of passive transfer (FPT) in day-old dairy calves fed a single feeding of CR. Single-dose packs of CR were sent to a commercial irradiation facility for electron-beam irradiation at 3 to 7 kGy (low irradiation) or 15 to 20 kGy (high irradiation). Fifty-six Holstein, Jersey, or crossbred calves were randomly assigned to 1 of 5 treatments: 1) 130 g of IgG (460 g of CR), no irradiation; 2) 130 g of IgG (460 g of CR), low irradiation; 3) 160 g of IgG (518 g of CR), low irradiation; 4) 190 g of IgG (575.4 g of CR), low irradiation; and 5) 130 g of IgG (460 g of CR), high irradiation. All CR were reconstituted in water and mixed in a household blender to a constant solids concentration of 18.7%. Increasing doses of irradiation (130 g of Ig with no, low, or high irradiation) resulted in a linear decrease in 24-h serum IgG and AEA of IgG, and increased the percentage of calves with FPT. Increasing the IgG mass in the CR (130, 160, and 190 g of Ig with low irradiation) resulted in a linear increase in 24-h serum IgG and serum total protein levels, and a linear decrease in AEA of IgG. There was no effect of increasing the mass of IgG fed on the percentage of calves with FPT. The correlation between serum IgG and serum total protein at 24 h was positive; however, at 24 h the irradiation treatments reduced the serum IgG-to-serum total protein ratio. In this study, CR isolated from bovine serum, providing 130 g of IgG in the first feeding and receiving either no irradiation or a low irradiation treatment, was sufficient to prevent FPT in calves.

The role of ascorbate and histidine in fibrinogen protection against changes following exposure to a sterilizing dose of γ-irradiation

Sodium ascorbate and histidine were employed to protect fibrinogen against modifications followed by a gamma-irradiation process that could potentially inactivate the blood-borne viruses in plasma-derived products. Fibrinogen was irradiated (50 kGy total dose, on dry ice) using a 60Co source. Samples were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blot. Carbonyl groups were measured by the 2,4-dinitrophenylhydrazine-coupled method, and the fibrinogen clotting activity was assessed by different functional assays. In irradiated fibrinogen, the carbonyl group concentration was elevated three-fold versus control; and moderate fragmentation of largely Aalpha and Bbeta chains was revealed. The rate of thrombin-catalyzed fibrinogen polymerization was inhibited (average 50%) with normal fibrinopeptide release and with a minor decrease of total clottable fibrinogen and alpha-polymer formation. Ascorbate reduced the incorporation of carbonyls to the fibrinogen molecule (by > 50% at 50 mmol/l; P < 0.001). Contrary to ascorbate, which alone delayed the fibrinogen polymerization rate, histidine abolished irradiation-induced inhibition of fibrinogen polymerization (by 80% at 50 mmol/l; P < 0.001). In conclusion, even though ascorbate effectively protects fibrinogen from oxidation due to its adverse effects on fibrinogen function, it may not serve as a suitable radioprotective. On the contrary, the first definite evidence is provided that radiation-sterilized fibrinogen in the presence of histidine greatly retains its clotting capability.

Haemostatic properties of human plasma subjected to a sterilizing dose of gamma irradiation in the presence of ascorbate

The objective was to study the effects of gamma irradiation, in the presence of sodium ascorbate, on coagulation/fibrinolytic activity of fresh frozen plasma to be applied to inactivate the transfusion-transmitted viruses in plasma-derived products. Plasma was irradiated (50 kGy total dose, on dry ice) using a 60Co source. The plasma proteins were analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and western blot and the following parameters estimated: prothrombin time, functional fibrinogen concentration, thrombin-induced fibrinogen polymerization, plasminogen activity, and tissue-type plasminogen activator-induced conversion of plasminogen to plasmin. In irradiated plasma a moderate fragmentation of the most labile plasma proteins was found. The prothrombin time was prolonged (1.5-fold), functional fibrinogen was significantly reduced (60%), fibrinogen polymerization was impaired, plasminogen was predominantly maintained (90%) and tissue-type plasminogen activator-induced conversion of plasminogen to plasmin was unchanged. Ascorbate (25 mmol/l) raised the level of functional fibrinogen in irradiated plasma (to 50%; P=0.0245) and slightly accelerated its polymerization. The small protective effect of ascorbate might be due to inhibition of the radiation-induced fibrinogen oxidation and/or fragmentation but addition of other antioxidants/stabilizers would be crucial when a high irradiation dose, an effective treatment for inactivation of the most resistant viruses, is applied.

Future of antibody purification

Antibody purification seems to be safely ensconced in a platform, now well-established by way of multiple commercialized antibody processes. However, natural evolution compels us to peer into the future. This is driven not only by a large, projected increase in the number of antibody therapies, but also by dramatic improvements in upstream productivity, and process economics. Although disruptive technologies have yet escaped downstream processes, evolution of the so-called platform is already evident in antibody processes in late-stage development. Here we perform a wide survey of technologies that are competing to be part of that platform, and provide our [inherently dangerous] assessment of those that have the most promise.

Virus safety of intravenous immunoglobulin: future challenges

Patients with immunodeficiencies or some types of autoimmune diseases are dependent on safe therapy with intravenous immunoglobulins. State-of-the-art manufacturing processes provide a high safety standard by incorporating virus elimination procedures into the manufacturing process. Based on their mechanism, these procedures are grouped into three classes: partitioning, inactivation, and removal based on size. Because of current socioeconomic and ecological changes, emerging pathogens continue to be expected. Such pathogens may spread very quickly because of increased intercontinental traffic. Severe acute respiratory syndrome-coronavirus and the West Nile virus are recent examples. Currently, it is not possible to predict the impact such a pathogen will have on blood safety because the capacity for a globally coordinated reaction to such a threat is also evolving. The worst-case scenario would be the emergence of a transmissible, small, nonenveloped virus in the blood donor population. Examples of small nonenveloped viruses, which change host and tissue tropism, are discussed, with focus on parvoviridae. Although today's immunoglobulins are safer than ever, in preparation for future challenges it is a high priority for the plasma industry to proactively investigate such viruses on a molecular and cellular level to identify their vulnerabilities.