Anti-Xa Stability of Diluted Enoxaparin for Use in Pediatrics

William E. Dager, Robert C. Gosselin, Jeffery H. King, Cinda L. Christensen, John T Owings, Edward C. Larkin

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


BACKGROUND: The use of enoxaparin in low-weight pediatric patients is becoming common practice. Anti-Xa stability of unit-dose syringes prepared after dilution beyond one day is presently unknown. OBJECTIVE: To evaluate the anti-Xa stability of diluted enoxaparin stored in glass vials and tuberculin syringes. METHODS: Four separate batches of enoxaparin were diluted with sterile water to a final concentration of 20 mg/mL (2000 IU/mL) and aliquoted into plastic 1-mL syringes containing 6 mg (0.3 mL) or maintained in the glass vial. Syringes were stored at room temperature or under refrigeration. The glass vial used for diluting was stored at room temperature. The anti-Xa activity was measured on the date of preparation to 4 weeks. Statistical comparisons determined whether differences in anti-Xa activity in diluted enoxaparin are affected by the storage medium or temperature. A paired t-test was used to determine any significant differences between the anti-Xa activity on date of preparation (baseline) and subsequent time periods, with p < 0.05 considered statistically significant. RESULTS: The mean baseline anti-Xa activity was 2607 IU/mL (95% CI 2300 to 2914). No measurable decrease occurred in diluted enoxaparin anti-Xa activity in the glass vial maintained over the 4-week period. Compared with the glass vial, room temperature and refrigerated syringe samples had trending decreases of anti-Xa activity at weeks 3 and 4, but did not reach statistical significance. CONCLUSIONS: A nonsignificant decrease in anti-Xa activity occurred starting at day 22 for the diluted enoxaparin in tuberculin syringes, regardless of storage temperature. Storage up to 4 weeks of diluted enoxaparin in glass or prefilled syringes does not result in a statistically significant loss of anticoagulant potential, as measured by anti-Xa activity.

Original languageEnglish (US)
Pages (from-to)569-573
Number of pages5
JournalAnnals of Pharmacotherapy
Issue number4
StatePublished - Apr 2004


  • Enoxaparin
  • Low-molecular-weight heparin
  • Pediatrics
  • Stability

ASJC Scopus subject areas

  • Pharmacology (medical)
  • Pharmacology, Toxicology and Pharmaceutics(all)


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