Stability of norfloxacin in an extemporaneously prepared oral liquid

The stability of norfloxacin in an extemporaneously prepared suspension sto red at room temperature and under refrigeration was studied over 56 days. A 20-mg/mL suspension was prepared from commercially available 400-mg norfl oxacin tablets and equal amounts of Ora-Plus and strawberry syrup to make a final volume of 60 mt. Six identical samples of the suspension were prepar ed in amber plastic prescription bottles. Three were stored at room tempera ture (23-25 degreesC) and three under refrigeration (3-5 degreesC). Immedia tely after preparation and at 7, 14,28, and 56 days, the samples were assay ed in duplicate by stabilily-indicating high performance liquid chromatogra phy. The samples were also inspected for color and odor changes and the pH of each sample was determined. At least 93% of tile initial norfloxacin concentration remained throughout the 56-day study period. The color, odor, and pH of all of the samples did not change appreciably. An extemporaneously prepared suspension of norfloxacin 20 mg/mL was stable for at least 56 days when stored at either 23-25 or 3-5 degreesC.