Comparison of serum cortisol concentrations in clinically normal dogs after administration of freshly reconstituted versus reconstituted and stored frozen cosyntropin.

OBJECTIVE

To evaluate the biological stability of reconstituted cosyntropin after storage at -20 C for 2, 4, and 6 months.

DESIGN

Prospective study.

ANIMALS

10 clinically normal dogs.

PROCEDURE

Serum cortisol concentrations in dogs were determined before and 1 hour after administration of freshly reconstituted cosyntropin (synthetic ACTH) or cosyntropin that had been reconstituted and stored frozen at -20 C in plastic syringes for 2, 4, and 6 months. Cosyntropin was administered at 5 micrograms/kg (2.3 micrograms/lb) of body weight, i.v.

RESULTS

Baseline serum cortisol concentrations were similar at each sampling time. Compared with the effects of freshly reconstituted cosyntropin, administration of cosyntropin that had been frozen did not have a significantly different effect on serum cortisol concentrations.

CLINICAL IMPLICATIONS

Cosyntropin can be reconstituted and stored frozen at -20 C in plastic syringes for 6 months with no adverse effects on bioactivity of the polypeptide.