The stability of calcitonin salmon in calcitonin salmon nasal spray at elevated temperatures was studied. Vials of calcitonin salmon nasal spray (2200 IU/mL) were stored for three days at 25, 40, or 60 degrees C or for three days at the same temperatures followed by two weeks at 5 degrees C and two additional weeks at 25 degrees C. Concentrations of calcitonin salmon and calcitonin C (a degradation product) were determined relative to a calcitonin salmon reference standard by high-performance liquid chromatography. Calcitonin salmon was stable under all study conditions except initial storage at 60 degrees C followed by two weeks at 5 degrees C and two weeks at 25 degrees C. The stability results were the same when determinations were made in terms of calcitonin C, which exceeded a 5% concentration only for samples stored for the extended period after initial storage at 60 degrees C. Calcitonin salmon remained stable in nasal spray after being stored for three days at 25 or 40 degrees C followed by two weeks at 5 degrees C and two weeks at 25 degrees C. Stability was lost during extended storage after initial storage at 60 degrees C.