Stability of proton pump inhibitors for use in hypersensitivity evaluation

Serious adverse drug reactions, including anaphylaxis and hypersensitivity reactions to proton pump inhibitors (PPIs), have been reported and are expected to rise as a result of their widespread use and over-the-counter availability. Relevant physicochemical stability information of PPIs for use in drug hypersensitivity evaluation is virtually unavailable. Appropriate shelf life determination of PPIs for skin testing will improve patient safety and streamline allergy testing procedures.

We studied the physicochemical stability of PPIs in plastic syringes.

PPIs' chemical stability was determined as a function of percentage of initial concentration remaining by a validated stability-indicating high-performance liquid chromatography method. Physical stability was monitored for the presence of precipitation, haziness, and color change by visible spectrophotometry and pH shift.

At refrigerated temperature, esomeprazole and omeprazole at 40 mg/mL and 4 mg/mL were stable for up to 7 days, while pantoprazole was stable for 7 and 2 days at 40 mg/mL and 4 mg/mL, respectively. At room temperature, esomeprazole and omeprazole at 40 mg/mL and 4 mg/mL, and pantoprazole at 4 mg/mL were stable for up to 2 days. Rabeprazole 20 mg/mL and 2 mg/mL were unstable at room temperature.

Aseptically prepared 40 mg/mL and 4 mg/mL esomeprazole and omeprazole, and 40 mg/mL pantoprazole have a maximum shelf life of 7 days when stored at 2°C to 8°C. At room temperature, aseptically prepared 40 mg/mL and 4 mg/mL esomeprazole and omeprazole, and 4 mg/mL pantoprazole can be used within 2 days of preparation, while 20 mg/mL and 2 mg/mL rabeprazole should be prepared fresh and used within 24 hours.