Physico-chemical stability of valproate sodium in polypropylene syringe for administration in the Intensive Care Unit

Background

The intensive Care Unit (ICU) use drug solutions within higher concentration to avoid fluid overload.

Purpose

To evaluate the physico-chemical stability of concentrated solution of valproate sodium in polypropylene syringe during 30 days at 5 ± 3°C.

Material and methods

Five syringes of 50 ml, containing 20.0 mg/ml of valproate sodium in 0.9 % NaCl were prepared and stored at 5 ± 3°C during 30 days. Immediately after preparation and periodically during the storage, valproate concentrations was measured by a high-performance liquid chromatography (HPLC). Spectrophotometric absorbance at different wavelengths, pH measurement and microscopic observations were also performed.

Results

All solutions were physically stable during the whole period storage at 5 ± 3°C: no color change, turbidity, precipitation or opacity at visual observation. No significant pH variations or optic densities were observed. Any crystals were seen by microscopic analysis. Solutions are considered chemically stable as the lower limit of the 95 % unilateral confidence interval on the mean remained above 90 % of the initial concentration for at least 30 days.

Conclusions

Solutions of valproate sodium 20.0 mg/ml in syringe of 0.9 % NaCl are physically and chemically stable for at least 30 days when stored in syringes at 5 ± 3°C and may be prepared in advanced by a CIVA.