Stroma-free haemoglobin solution for infusion: changes during storage.

The stability of experimental haemoglobin solution for infusion (HSI) was investigated during one year storage at temperatures 20 degrees to 25 degrees C, 4 degrees C, -8 degrees to -12 degrees C, and -195.8 degrees C, respectively. Main attention was devoted to the formation of precipitate, oxidation to haemiglobin and general changes in the absorption spectrum between 550 and 650 nm. Changes were almost negligible in HSI samples stored in the frozen state. This procedure now seems the most feasible to keep the HSI injectable for at least one year. Storage at 4 degrees C led to a marked increase of haemiglobin and to changes of the absorption spectrum. Storage at 20 degrees to 25 degrees C caused profound changes of all parameters tested. Addition of EDTA, ascorbic acid or glutathione, or storage in N2 atmosphere under the given conditions failed to increase the stability of HSI. Storage of HSI samples at pH values between 7.0 and 7.8 led to similar results.