Stability of Extemporaneously Prepared Sodium Benzoate Oral Solution

Purpose: Sodium benzoate (NaC7H5O2), a common food preservative, is the salt form of benzoic acid. It is used as an alternative treatment in patients with hepatic encephalopathy or urea cycle disorders as it is believed help stimulate ammonia removal via a non-urea cycle based pathway. Despite its use, sodium benzoate is not an FDA approved medication and has no commercially available oral formulations, although an IV formulation is available in combination with sodium phenylacetate (Ammonul®). The objectives of this study were to prepare a sodium benzoate solution and determine the stability of an extemporaneously prepared oral solution over a 90-day period. Methods: An oral solution of sodium benzoate was prepared and a 1 ml sample was withdrawn from each bottle immediately after preparation and at 7 and 14 days and assayed for drug concentration by stability-indicating high performance liquid chromatography. Stability of sodium benzoate solution will be defined as maintenance of greater than or equal to 90 percent of the initial concentration. Results: The sodium benzoate maintained 96% and 93% of the initial concentrationt at 7 and 14 days, respectively. Therefore, sodium benzoate oral solution in cherry syrup is stable for a minimum of 14 at room temperature