Formulation and Stability Study of Omeprazole Oral Liquid Suspension for Pediatric Patients

Objectives: To develop and to study the physicochemical and microbiological stability of omeprazole liquid oral formulations used as therapeutic agent in many acid-related disorders, for pediatric use. Furthermore, to optimize and validate a stability-indicating high-performance liquid chromatography (HPLC) method for the analysis of omeprazole in the studied formulations. Method: Oral liquid suspensions of omeprazole were prepared at 2 mg/mL using crushed omeprazole pellets (formulation A) and pure omeprazole (formulation B) with a complete vehicle including humectant, suspending, sweetening, antioxidant, and flavoring agents. Samples were stored at 4°C and 25°C. Omeprazole content of each formulation was analyzed in triplicate using micro-HPLC at 0, 3, 7, 14, 30, 60, 90, 120, and 150 days. Other parameters were also determined, such as appearance, pH, resuspendibility, and viscosity. Microbiological studies were conducted according to the United Stated Pharmacopeia (USP) guidelines for non-sterile products. Results: Formulation A stayed physicochemical and microbiologically stable at refrigerated (4°C) conditions during at least 150 days and it only stayed stable during 14 days at 25°C. Formulation B was stayed physicochemical and microbiologically stable at refrigerated (4°C) conditions at least 90 days, but it is not recommended to store at 25°C for more than 1 day. Conclusions: Formulation A and formulation B can be stored for at least 150 and 90 days, respectively, at refrigerated conditions. Formulation A can be stored at room temperature for 14 days. Both formulations are perfectly suitable for pediatric patients who are usually notable to swallow solid oral formulations. The proposed analytical method was suitable for the study of stability of different formulations.