Tsugikazu Tomono

Removal of small non-enveloped viruses by nanofiltration.

Background and Objectives  Nanofiltration is one of the most effective virus reduction methods in the manufacturing process of plasma products. However, it is difficult to remove small viruses from high molecular weight protein preparations like immunoglobulin G or factor VIII complex by nanofiltration, because the size of the protein is similar to that of viruses. In order to separate the viruses from these proteins by nanofiltration, it is necessary to change the size of either one. In this study, we report that such non‐enveloped viruses as human parvovirus B19 (B19), human encephalomyocarditis virus (EMC) or porcine parvovirus (PPV) aggregate in the presence of certain kinds of amino acids and could be easily removed by nanofiltration.

Implementation of a 20‐nm pore‐size filter in the plasma‐derived Factor VIII manufacturing process

Background and Objectives  Virus inactivation and removal are important prerequisites to ensure the safety of plasma derivatives. For virus inactivation and removal in our coagulation factor VIII (FVIII) product, CROSS EIGHT M®, the production process consists of solvent–detergent (S/D) treatment, two chromatography steps and virus filtration with a 35‐nm pore‐size filter. However, the clearance of non‐enveloped viruses was not as good as that of enveloped viruses because non‐enveloped viruses are resistant to S/D treatment and are too small to be removed by the filter. In this study, in order to improve the viral safety of the FVIII products, we attempted to replace the 35‐nm pore‐size virus filter with a 20‐nm filter.

A New Intact Immunoglobulin for Intravenous Use Stabilized by Chemically Modified Gelatin Derivatives

Abstract. The stabilization of human immunoglobulin (IgG) by chemically modified gelatins (Haemaccel and Gelofusine) was investigated. The gelatins prevented IgG from aggregation induced by exposure to interfaces and lyophilization. The stabilization effects of the gelatins were significantly larger than those of amino acids or sugars. These investigations led to the large‐scale production of an immunoglobulin preparation for intravenous use in the clinic. The clinical product meets the Japanese minimum requirements for immunoglobulin preparations for intravenous use, and the long‐term preservation of this new freeze‐dried preparation has demonstrated its stability.

Interactions of human serum albumin with a modified poly(vinyl alcohol) gel packing for high-performance liquid chromatography

The interactions of human serum albumin (HSA) with a poly(vinyl alcohol) gel packing (Asahipak GS-520) for high-performance liquid chromatography of proteins were investigated. Under certain conditions, the elution of HSA from the GS-520 column was retarded and its chromatogram was split into two peaks, indicating weak adsorption of HSA onto the gels and also the existence of two subfractions, i.e. human mercapto-albumin (HMA) and human non-mercapto-albumin (HNA). The chromatograms were confirmed to be greatly influenced by the salt composition, the pH, and the temperature of the isocratic mobile phase. It is characteristic for the adsorption of HSA onto the gels to be suppressed at a pH near its isoelectric point. The HSA-gel interaction parameters calculated using an adsorption chromatography theory demonstrate that the adsorption of HSA is caused by enthalpy-driven interactions, which are depressed by lowering the pH, in addition to hydrophobic interactions. Under the recommended chromatographic conditions for high resolution of HMA/HNA, it was found that the HSA samples possessed some subfractions besides HMA and HNA fractions.

Alternating Copolymer Graft Copolymers - XI. Grafting through Matrix Polymerization

The comonomer complexes generatedas a result of the interaction of a donor monomer and an acceptor monomer in the presence of a complexing agent are arrayed in the form of a matrix and undergo radical initiated homopolymerization to yield an alternating copolymer. The array of complexes formed when the copolymerization is carried out in the presence of a polymer which has been precomplexed with a complexing agent undergoes homopolymerization to yield grafted and ungrafted alternating copolymers. Cellulose behaves as a complexing agent per se and, acting as a matrix, promotes the formation of an array of comonomer complexes which homopolymerizes in water to yield grafted and ungrafted alternating copolymers when the water and cellulose contents of the system are maintained within certain Iimits. INTRODUCTION The copolymerization of a strong donor monomer and a strong acceptor monomer, e.g. styrene and maleic anhydride or vinylidene cyanide, yields equimolar, altemating copolymers essentially independent of comonomer feed ratios. The polymerization rnay occur spontaneously at elevated temperatures, in the presence of a free radical precursor or under ultraviolet irradiation. The formation of altemating copolymer has been attributed to the homopolymerization of a comonomer donor-acceptor charge transfer complex, whose concentration is dependent upon temperature and dilution, i.e. concentrations of monomers and reaction medium. The polymerizable species is actually the excited complex, generated spontaneously or thermally when the concentration of ground state complexes is su:fficiently high. Excitation of ground state complexes also occurs in the presence of a free radical precursor as weil as under u. v. irradiation.

Interfacial properties of poly(ethylene glycol)-grafted immunoglobulin G.

塩化シアヌルで活性化したポリエチレンゲリコール (PEG) をグラフト化したヒト免疫グロブリンG (IgG) の界面凝集性・界面活性に及ぼす, PEG分子量, グラフト化量の影響について検討した. IgGの界面凝集性は, グラフトするPEGの分子量, 分子数が増加するほど低下した. 分子量5.600のPEGでは, IgG1分子あたり1分子のPEGをグラフトすると, ほぼ完全に凝集が抑制された. 一方, PEGグラフト化IgG溶液の表面圧は, ヒト血清アルブミンのそれより高く, PEGの分子量・分子数が増加するほど上昇した. このような界面化学的性質は, 界面へのPEGの優先吸着と, 界面領域からのIgG分子の排除に由来するものと解釈された.

ALTERNATING COPOLYMER GRAFT COPOLYMERS—XI. GRAFTING THROUGH MATRIX POLYMERIZATION†

The comonomer complexes generated as a result of the interaction of a donor monomer and an acceptor monomer in the presence of a complexing agent are arrayed in the form of a matrix and undergo radical initiated homopolymerization to yield an alternating copolymer. The array of complexes formed when the copolymerization is carried out in the presence of a polymer which has been precomplexed with a complexing agent undergoes homopolymerization to yield grafted and ungrafted alternating copolymers. Cellulose behaves as a complexing agent per se and, acting as a matrix, promotes the formation of an array of comonomer complexes which homopolymerizes in water to yield grafted and ungrafted alternating copolymers when the water and cellulose contents of the system are maintained within certain limits.