Can I freeze the unused portion of the reconstituted collagenase and use it at a later time?

Yes.

Internal studies have shown the reconstituted collagenase is stable as a frozen solution between -15 to -25°C for at least 1 year as long as no other protease enzymes have been added to the collagenase solution. For ensured stability it is best to minimize the volume used for dissolution and reconstitute with water or a phosphate-free buffer. Additional studies have shown the reconstituted collagenase was successfully frozen and thawed three times as a concentrated solution with no apparent loss of potency as assessed by the CDA assay.