Formulation and Clinical Evaluation of Sodium Benzoate Oral Solution for the Treatment of Urea Cycle Disorders in Pediatric Patients

Background: Sodium benzoate, a common food preservative, is used in the treatment of patients with urea cycle disorders (UCDs) as it stimulates ammonia removal by a non-urea cycle–based pathway. Despite its use in the clinical routine, no commercially available oral formulations currently exist. Liquid formulation is normally well accepted in pediatric age and allows precise dosage according to the children’s needs. Aims: (1) To prepare an oral sodium benzoate solution in different tastes and determine its stability, palatability, and tolerability and (2) to describe the long-term follow-up of two pediatric patients with UCDs treated with our formulation. Methods: We prepared five oral solutions of sodium benzoate (200 mg/ml) by adding different flavoring agents. We measured drug concentration in the samples by high-performance liquid chromatography (HPLC). We evaluated palatability and tolerability with adult volunteers. Long-term drug compliance and metabolic control were appraised in two pediatric patients. Results: All the oral solutions remained stable at room temperature along the 96-day test period, and they were well tolerated. The mint-flavored solution resulted the most palatable and preferred by adult volunteers. We report good drug compliance and good metabolic outcomes for both pediatric patients during the entire follow-up. Conclusions: Our study highlighted the stability and tolerability of flavored sodium benzoate oral solutions. These solutions were well accepted during a long-term follow-up and guaranteed a good metabolic control. Since taste attributes are critical to ensure acceptable medication adherence in the pediatric age, flavored liquid formulations of sodium benzoate may be an efficient strategy to achieve therapeutic outcomes in UCD pediatric patients.