VitriBlast™ contains hSA and it is most likely that DMSO oxidizes hSA into dimers and/or oligomers since it has an oxidative effect and thereby creating disulfide bridges. The reaction is rather slow but, if DMSO and hSA exist together for a longer time, it is likely that these bonds are created.

Every hSA protein contains a free cystein which could be oxidized. hSA also contains several internal disulfide bridges which could be opened and reclosed at another position, or react with another hSA-molecule (tiol-disulfide exchange) due to the effect of DMSO. This could lead to a number of different combinations of hSA with an oligomer of hSA as the result.

Regardless of whether dimers or oligomers are created, hSA is changed to such a degree that it would not function properly as an excipient, since its tertiary structure is so different from native hSA.

In short: DMSO inhibits the function of hSA in the medium, although only if added to VitriBlast™ earlier than just prior to use.

References

Recovery and purification of highly aggregation-prone disulfide-containing peptides: Application to islet amyloid polypeptide

Andisheh Abedini, Gagandeep Singh a, Daniel P. Raleigh

Analytical Biochemistry 351 (2006) 181–186

SOLVATION EFFECTS IN HUMAN SERUM ALBUMIN RADIOLYSIS IN THE PRESENCE OF DIMETHYL SULFOXIDE

V. K. Pogorelyi, V. N. Barvinchenko,and V. V. Turov.

Teoreticheskaya i Eksperimental'naya Khimiya 26 ( 1988 ) 107-110. Translated January-February, 1990. Original article submitted August 18, 1988