Physicochemical stability of 20 mg/mL amiodarone hydrochloride oral suspension in SyrSpend® SF PH4 (liquid)

Abstract Objectives Amiodarone hydrochloride is a class III antiarrhythmic drug indicated for the treatment of ventricular and supraventricular tachycardias. Oral amiodarone is only available in a tablet dosage form, which is not suitable for pediatric use. The stability of amiodarone hydrochloride suspension at 5 mg/mL was assessed in SyrSpend® SF PH4 (liquid) but oral amiodarone is typically given as a loading dose of 10–15 mg/kg/day for 4–10 days and then reduced to a maintenance dose of 5 mg/kg/day, making the 20 mg/mL concentration a better option. A hospital preparation of 20 mg/mL amiodarone hydrochloride oral suspension was developed. The purpose of this study was to determine the physicochemical stability of a 20 mg/mL amiodarone hydrochloride oral multidose suspension in a commercial compounding excipient, SyrSpend® SF PH4 (liquid) at ambient temperature and under dark conditions. Methods Three batches of oral suspension were prepared using amiodarone hydrochloride powder and SyrSpend SF PH4 (liquid). The suspensions were stored at room temperature and protected from light (amber glass vials). A sample was withdrawn from each bottle immediately after preparation and at 1, 2, 5, 10, 15, 30, 60, and 90 days. After additional dilution to an expected concentration of 100 μg/mL with methanol, the samples were assayed in triplicate using a stability-indicating high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection. The physicochemical properties (pH, osmolality, amiodarone concentration, macroscopic changes) were assessed over 90 days at each day of analysis. Stability was determined by evaluating the percentage of the initial concentration remaining at each time point and defined as retention of at least 95% of the initial concentration of amiodarone hydrochloride. Results After 90 days, the study showed that amiodarone hydrochloride concentrations did not go below 95% of the initial drug concentration. Neither degradation products nor changes of physicochemical properties were detected. Conclusions Compounded oral suspensions of 20 mg/mL amiodarone hydrochloride in SyrSpend® SF PH4 (liquid) were stable for at least 90 days when stored in amber glass bottles at room temperature.