High-Yield Method of Production of Freeze-Dried Purified Factor Viii by Blood Banks

The influence of heparin alone or in conjunction with calcium chloride on the coagulation assay for factor VIII, on the stability of factor VIII in blood and in plasma, and on the recovery of factor VIII in cryoprecipitate and in an intermediate purity concentrate was investigated. A stabilizing effect of heparin and calcium on factor VIII activity in blood and plasma could be confirmed. We were, however, unable to make use of the higher activity that can, under certain circumstances, be recovered in the cryoprecipitates; this was mainly due to the poor solubility of cryoprecipitates prepared from heparinized blood. Heparin (or the absence of a calcium chelator) also interferes with the recovery of plasma components other than factor VIII.

Section: Introductionmentioning

confidence: 99%

Influence of Heparin and Calcium Chloride on Assay, Stability, and Recovery of Factor VIII

Morgenthaler¹,

Zuber²,

Friedli³

1985

“…Citrate was also reported to have a marked stabilising effect on chromatographically purified factor VIII [29], a finding which helped to establish its use at a concentration of 20 nrMin the final product formulation [30], Virtually all manufacturers of factor VIII concentrate have adopted this concentration, exceptions being Smith et al [31 ], who used lOmM citrate, and Liu et al [7], who used a phos phate buffer. Various other additives have been utilised to aid factor VIII stability or product formulation includ ing heparin [32][33][34], glycine [14,34] and sugars [26,34,35], process stream to maintain a constant concentration of ionised calcium, while retaining the standard citrate con centration used by almost all manufacturers of factor VIII concentrates. In doing this we were concerned that some form of activation might be induced and the discrepancy between one-stage and two-stage assay results gave fur ther emphasis to this concern.…”

Section: Discussionmentioning

confidence: 99%

Studies on the Stability of VIII:C during the Manufacture of a Factor VIII Concentrate for Clinical Use

Foster¹,

Dickson²,

McQuillan³

et al. 1988

The stability of VIII:C was investigated by monitoring samples taken at different points from a routine process for the manufacture of factor VIII concentrate and by examining the stabilising influence of a number of product formulations. Loss of VIII:C over process-finishing procedures (formulation, 0.22 µm filtration, dispensing) was associated with a citrate-induced inactivation which could be prevented by controlling the ionised calcium concentration of the solution. These results were obtained using a one-stage clotting assay but were not observed using a two-stage assay. No evidence for activation was found in vitro (e.g. by FPA generation and VIII:C stability) and the yield increase suggested by the one-stage assay was supported by results from a controlled clinical evaluation.

“…Recent reports [10,11] suggest that re placement of citrate anticoagulant with hep arin, or recalcification of citrated plasma under the protection of heparin [13] greatly enhances factor VIII yield, possibly by sta bilising the factor VIII molecule, preventing enzymic degradation or possibly by assisting cryoprecipitation. Such modifications can readily be incorporated into an automated plasmapheresis system and studies along these lines are already underway in this centre.…”

Section: Discussionmentioning

confidence: 99%

Pilot Study for Large-Scale Plasma Procurement Using Automated Plasmapheresis

Robinson¹,

Penny²,

Smith³

et al. 1983

A pilot study for large-scale automated plasmapheresis using the Haemonetics Model 50 machine was undertaken in the Yorkshire Region of the United Kingdom to determine the viability of such a programme for national self-sufficiency in fresh plasma procurement for factor VIII concentrate production. The study was designed to resolve three areas of concern; donor safety and recruitment; a cost analysis, and the choice of anticoagulant for optimum factor VIII yields. The results show that large-scale automated plasmapheresis could safely and economically produce high-quality source plasma necessary for national self-sufficiency.