Stability of propranolol hydrochloride suspension compounded from tablets

The stability of a propranolol hydrochloride suspension compounded from commercially available tablets was studied. Propranolol hydrochloride 10-mg tablets were triturated to a powder and incorporated into a commercially available suspension vehicle to yield a suspension with a theoretical propranolol hydrochloride concentration of 1 mg/mL. The suspension was divided into portions and stored in amber glass bottles at either room (25 degrees C) or refrigerated (2 degrees C) temperature for four months. The concentration of propranolol hydrochloride in the samples was determined by a stability-indicating, high-performance liquid chromatographic (HPLC) assay at 0, 30, 60, 90, and 120 days. Also at these times, the pH of the samples was measured, and the samples were inspected visually for evidence of microbial growth and ease of resuspension. The concentration of propranolol hydrochloride in the samples remained within 90% of the initial concentration throughout the study period. No important changes in the pH of the samples and no visible evidence of microbial growth were noted. This extemporaneous suspension of propranolol hydrochloride compounded from commercially available tablets is stable for at least four months when stored at room or refrigerated temperature.