Vancomycin: stability in syringes

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Chemical stability and microbiological potency of intravenous
vancomycin hydrochloride in polypropylene syringes for use in
the neonatal intensive care unit

Study objectives : To determine the chemical stability and microbiological potency of “almost” ready-to-use vancomycin solutions in polypropylene syringes at a concentration of 5 mg/mL in both 5% glucose and 0.9% sodium chloride at 4°C and 25°C, for use in the neonatal intensive care unit.

Methods: Ten-millilitre syringes were filled using aseptic techniques with a solution of vancomycin, covering body weights of 500 g to 3 kg at a dosage of 15mg/kg, prepared by reconstitution and dilution of commercially available vancomycin hydrochloride powder (Vancocin) and kept at 4°C and 25°C, respectively. At various storage times, the chemical stability was determined using a high-performance liquid chromatography method and the microbiological potency was assayed according to the European Pharmacopoeia 2002. Arbitrarily, 56 day samples at 4°C were brought to 25°C and analyzed after 48 hours to simulate ward conditions. The standards were the T0 solution kept at -70°C and the International Vancomycin Reference Standard.

Results: The vancomycin was found to be chemically and microbiologically stable at 4°C for 6 months. Losses were important after 14 days at 25°C in both cases. The samples subjected to simulated ward conditions were stable for 48 hours at 25°C. A shelf life of 6 months was proposed.

Conclusions: Syringes of low dose vancomycin manufactured and supplied by the pharmacy can be stored in the neonatal intensive care unit refrigerator for use in emergency situations thus avoiding calculation and dilution errors and reducing the risk of bacterial contamination. The solution brought to 25°C must be used within 48 hours.

References: This work was presented as a poster at the 8th congress of the European
Association of Hospital Pharmacists, Florence, Italy, 2003.

Dr Pascal Bonnabry, Head of pharmacy, Pharmacy Department University Hospitals of Geneva (HUG). William Griffiths, PharmD, Jocelyne Favet, PhD, Ho Ing, PharmD, Farshid Sadeghipour, PhD, Pascal Bonnabry, PhD