High-vacuum condensation drying of proteins from the frozen state

Abstract

1. Methods are described for the preservation by desiccation from the frozen state of large volumes of protein, both in bulk and in ampoules.2. The principle is one of high-vacuum condensation drying, utilizing liquid air for quantities up to 250 c.c. or refrigerator evaporator coils for quantities up to 5 l. Desiccators, not manifolds, are used throughout.3. Use is made of an accurate automatic control of heat to the frozen material. By recording this heat input a visual record is obtained indicating when the end-point of desiccation has been reached, and, furthermore, it is possible to calculate from this record the approximate percentage dryness of the material at any period of desiccation.4. The control of the apparatus is such that within stated limits the conditions of desiccation can be altered at will.5. In this form of apparatus obstruction to the flow of water vapour is so small that plugged containers may be used, thus preventing contamination of the material while it is being dried.6. In its final form the apparatus is entirely automatic and the running costs are extremely low.7. Suggestions are made for designing forms of apparatus to meet many requirements.

Past meets present: Reviving 80‐year‐old Canadian dried serum from World War II and its significance in advancing modern freeze‐dried plasma for prehospital management of haemorrhage

“…8 Meanwhile Cambridge University researchers Ronald Greaves and Muriel Adair developed large-scale reliable methods of mechanically refrigerated freeze-drying. 9,10 Their work developed freeze-drying facility in the United Kingdom that became operational in 1940, playing a pivotal role in producing an additional 500 000 dried plasma bottles. 9,10 Towards the end of the war, hepatitis transmission from pooled dried plasma and serum became a concern, and rose to 21% during the Korean War, which led to its discontinuation as irradiation methods failed to eliminate pathogens.…”

“…9,10 Their work developed freeze-drying facility in the United Kingdom that became operational in 1940, playing a pivotal role in producing an additional 500 000 dried plasma bottles. 9,10 Towards the end of the war, hepatitis transmission from pooled dried plasma and serum became a concern, and rose to 21% during the Korean War, which led to its discontinuation as irradiation methods failed to eliminate pathogens. 8,11 Resuscitation using whole blood is ideal because it contains red blood cells (RBCs; oxygenation), platelets (primary haemostasis) and plasma (secondary haemostasis and maintains blood volume).…”

A pressure-operated safety circuit for use in high-vacuum serum-drying plants

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The successful operation of the Greaves-Adair (1939) and similar processes for drying blood serum by sublimation from the frozen state depends on the maintenance of an adequate vacuum in the desiccating chamber. If the pressure in the region of the refrigerated condenser coils should rise materially above the operating range of 0 10-0 05 mm.

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The Concentration and Drying of Plasma

“…in twentyfour hours. Greaves and Adair (1936) have described a simple method for the desiccation of small amounts of serumn, using a high vacuum and phosphorus pentoxide as a desiccant later (1939) they described a large-scale apparatus which is capable of drying 5 litres, either in bulk or in ampoules, the serum being frozen and the moisture distilled into a condensing system cooled with refrigerator coils at -450 C. Their paper contains a very full description of the physico-chemical aspects of the drying process. From the accounts given by the different workers it would appear that there is no difficulty in producing small amounts of sterile dried serum on a laboratory scale, but the drying of large volumes requires considerable capital expenditure in apparatus.…”