Stability of levofloxacin in an extemporaneously compounded oral liquid

The stability of levofloxacin in an extemporaneously compounded oral liquid was studied. A suspension of levofloxacin 50 mg/mL was prepared from commercially available 500-mg levofloxacin tablets and equal amounts of Ora-Plus and Strawberry Syrup, NF, to make a final volume of 60 mL. Six identical volumes of the suspension were prepared in amber plastic prescription bottles. Three bottles were stored at 23-25 degrees C, and three were stored at 3-5 degrees C. Immediately after preparation and at 8, 15, 29, and 57 days, samples were visually inspected and assayed in duplicate by high-performance liquid chromatography; pH was also determined. At least 99% of the initial levofloxacin concentration remained in all samples throughout the study period. The color, odor, and pH of all the samples did not change appreciably. An extemporaneously compounded oral liquid formulation of levofloxacin 50 mg/mL in a 1:1 mixture of Ora-Plus and Strawberry Syrup, NF, was stable at 23-25 or 3-5 degrees C for up to 57 days.