Manufacturing process of anti-thrombin III concentrate: viral safety validation studies and effect of column re-use on viral clearance

Virus and chlorine adsorption onto guanidine modified cellulose nanofibers using covalent and hydrogen bonding

Unsafe drinking water leads to millions of human deaths each year, while contaminated wastewater discharges are a significant threat to aquatic life. To relieve the burden of unsafe water, we are in search of an inexpensive material that can adsorb pathogenic viruses from drinking water and adsorb toxic residual chlorine from wastewater. To impart virus and chlorine removal abilities to cellulosic materials, we modified the primary hydroxyl group with a positively charged guanidine group, to yield guanidine modified cellulose derivatives. Microcrystalline cellulose (MC) bearing covalently bonded guanidine hydrochloride (MC-GC) and hydrogen-bonded guanidine hydrochloride (MC-GH) were synthesized, and electrospun into nanofibers after blending with the non-ionogenic polyvinyl alcohol (PVA), to produce large pore sized, high surface area membranes. The MC-GC/PVA and MC-GH/PVA nanofibers were stabilized against water dissolution by crosslinking with glutaraldehyde vapor. The water-stable MC-GC/PVA mats were able to remove more than 4 logs of non-enveloped porcine parvovirus (PPV) and enveloped Sindbis virus and reached 58% of chlorine removal. The MC-GC/PVA nanofibers demonstrated better performance for pathogen removal and dechlorination than MC-GH/PVA nanofibers. This first study of MC-GC/PVA electrospun mats for virus removal shows they are highly effective and merit additional research for virus removal.

Virus elimination during the recycling of chromatographic columns used during the manufacture of coagulation factors

Various chromatographic procedures are used during the purification and manufacture of plasma products such as coagulation factors. These steps contribute to the overall safety of such products by removing potential virus contamination. Virus removal by two affinity chromatography procedures, i.e. monoclonal antibody chromatography and metal chelate chromatography (immobilised metal ion affinity chromatography), used during the manufacture of the high purity factor VIII (Replenate®) and factor IX (Replenine®-VF), respectively, has been investigated. In addition, as these columns are recycled after use, the effectiveness of the sanitisation procedures for preventing possible cross-contamination, has also been investigated. Both chromatographic steps proved effective for eliminating a range of model enveloped and non-enveloped viruses by 4 to >6 and 5 to >8 log for the monoclonal and metal chelate columns, respectively. The effectiveness of the relatively mild column sanitisation conditions used, i.e. ethanol for factor IX and acetic acid for factor VIII, was confirmed using non-spiked column runs. The chemicals used contributed to virus elimination by inactivation and/or by physical removal of the virus. In summary, these studies demonstrate that potential virus contamination between chromatographic runs can be prevented when an effective column recycling and sanitisation procedure is included.

[Role of antithrombin iii in cardiac surgery]

Coagulation of blood is of multidisciplinary interest. Cardiac surgery produces major changes in the delicate balance between pro-and anti-coagulant serum factors. The role of antithrombin iii has been analysed after finding evidence that associated decreased levels of protein activity to postoperative morbidity and mortality. Supplementing exogenous antithrombin is considered with the aim of optimising outcomes. Its intrinsic anticoagulant and anti-inflammatory properties have stimulated a growing interest, and suggests new lines of research.

Safety of the production process of SURFACEN(®) to inactivate and remove virus

SURFACEN(®) is a biological product produced from pig lungs. Since these animals can be potential sources of microbial pathogens such as viruses, the manufacturing process of this product should guarantee safety from health hazards. The SURFACEN(®) production procedure is capable of effective viral clearance (inactivation/removal) by involving two stages of organic solvent extraction followed by acetone precipitation and heat treatment. In this study, we evaluated the clearance capacity of these four stages for a wide range of viruses by performing spiking experiments. Residual contamination was assessed using a Tissue Culture Infectious Dose assay (log10 TCID50). The validation study demonstrated that, for all viruses tested, the TCID50 titers were reduced by more than 2 log10 in each stage. Total log reduction values achieved were between ≥17.82 log10 and ≥27.93 log10, depending on the virus physical properties, titer, and the number of processing stages applied. Results indicated that the production procedure of SURFACEN(®) can inactivate or remove contaminant viruses from the raw material.

Validation of model virus removal and inactivation capacity of an erythropoietin purification process

Human erythropoietin (hEpo) production requires mammalian cells able to make complex post-translational modifications to guaranty its biological activity. As mammalian cell can be reservoir of pathogenic viruses and several animal origin components are usually used in the cultivation of mammalian cells, hEpo contamination with viruses is something of great concern. As consequence, this study investigated the viral removal and inactivation capacity of a recombinant-hEpo (rec-hEpo) purification process. Canine parvovirus, Human poliovirus type-2, Bovine viral diarrhea virus and Human immunodeficiency virus type-1 were used for measuring process viral removal and inactivation capacities. In conclusion, this study corroborated that the assessed rec-hEpo purification process has enough capacity (5.0-19.4 Logs) for removing and inactivating these model viruses and sodium hydroxide demonstrated to be a robust sanitization solution for chromatography columns (5.0 (PV-2)-6.7 (CPV) Logs).

Binding Aedes aegypti densonucleosis virus to ion exchange membranes

Experimental and numerical results for binding Aedes aegypti densonucleosis virus (AeDNV) using anion and cation exchange membranes are presented. AeDNV particles are adsorbed by anion and cation exchange membranes providing the virus particles and membranes are oppositely charged. Q membranes which are strongly basic anion exchangers were the most effective. Dynamic and static capacities for Q membranes were found to be similar. A numerical model is proposed which assumes a log normal pore size distribution. By estimating the required parameters from static binding experiments, the model may be used to calculate the breakthrough curve for virus adsorption.