Stability of Low-Dose Vancomycin Hydrochloride in Heparin Sodium 100 IU/mL

Abstract

Objective:

To determine the stability of low-dose vancomycin hydrochloride 25 μg/mL and preservative-free heparin sodium 100 IU/mL stored at room temperature versus refrigerated temperature for 100 days.

Design:

A prospective, controlled pharmacologic study.

Materials:

The test article (V-H) was prepared by mixing vancomycin hydrochloride 25 μg/mL in heparin sodium 100 IU/mL. The antibiotic control (V) was the same dose of vancomycin in NaCl 0.9% only The heparin control (H) was commercially available 100 IU/mL vials of this agent.

Methods:

Half of the test and control solutions were stored at room temperature (28 °C) and half were kept in a refrigerator (4 °C). On study days 0, 1, 14, 30, 63, and 100, the concentration of vancomycin was measured by Emit. The functional activity of heparin was determined on identical days by the activated partial thromboplastin time (aPTT) assay.

Results:

Sixty-three days after preparation, the refrigerated V-H solution maintained over 90% of its original vancomycin concentration; in contrast, the V-H solution kept at room temperature had a 21% reduction in its antibiotic concentration. All V-H and V solutions had a significant (p = 0.01) drop in their vancomycin concentrations after 100 days of storage. There was no significant change in the measured aPTT of the V-H and H solutions stored in the refrigerator versus room temperature for 0 versus 100 days (p = 0.35 and p = 0.41, respectively).

Conclusions:

An admixture of vancomycin hydrochloride 25 μg/mL and heparin sodium 100 IU/mL is stable for up to 63 days when stored at 4 °C.