Essential Chemistry and Biochemistry Associated with Low Temperature and Freezing - Freeze-drying of Pharmaceuticals and Biopharmaceuticals - page 51

Figure 3 A comparison of the effects of freezing and salt exposure at room temperature
on the haemolysis of erythrocytes. Salt concentrations corresponding to de-
creasing temperatures are indicated; constructed from data by Lovelock 53
injury'', 53 and often attributed to ice crystals, is in fact a concentration
damage that can equally well be induced at ambient temperature and
concentrations equivalent to those produced by freezing the solution to
the equivalent temperature. The comparison in Figure 3 graphically
shows that, when a suspension of human red blood cells in isotonic
saline solution is frozen to -81C, the solution has been freeze-concen-
trated to 2.5 M. Upon thawing, a 50% haemolysis is observed. The same
result is obtained by incubating the cells in 2.5 M of NaCl at ambient
temperature. 54 The damage to the cells should therefore be referred to
more correctly as ''concentration injury''. It must, however, be realised