Background Omeprazole by intravenous infusion is occasionally warranted in children during episodes of acute upper gastrointestinal bleeding. This is to ensure the continued suppression of stomach acid to reduce the of risk of rebleeding.

Methods Current practice in UK paediatric intensive care units varies, but the use of 160 mg/1.73 m³ over 24 hours has previously been reported.¹ This is commonly prepared as a 0.8 mg/ml solution changed either at 12 or 24 hrs after preparation depending on reference source used.^2-3 The current practice of using a 0.8 mg/ml (40 mg/50 ml) is off label and not endorsed by manufacturers who recommend a maximum concentration of 0.4 mg/ml³.

Following these recommendations would lead to a fluid load of 400 ml/1.73 m² which is likely to be significant. Excess fluid intake has been shown to correlate with increased oxygenation index and increased PICU stay.⁴

The aim of this study is to provide stability data for using 0.8 mg/ml for intravenous infusion which is currently in wide spread despite use a lack of published lack of data in this area.

Methods A series of analytical techniques were performed to assess physical and chemical stability. Test solutions were pre pared by reconstituting Losec® (Omeprazole) 40 mg powder for infusion and diluting to either 50 ml or 100 ml in 0.9% sodium chloride.

Reverse phase HPLC analysis was conducted at 0 hrs, 10 hrs and 24 hrs. Particle size was assessed using a zeta potential analyser at 15-minute intervals over 60 minutes.

Results At both 40 mg/50 mL and 40 mg/100 mL the concentration of omeprazole remained at 101% and 100% after 10 hours respectively. However, significant degradation was seen at 24 hours as concentrations reduced to 60% and 55% respectively.