AK-FLUORŪ (Fluorescein Injection, USP) is a sterile solution in Water for Injection, of Fluorescein prepared with the aid of Sodium Hydroxide. Hydrochloric Acid and/or Sodium Hydroxide may be used to adjust pH (8.0-9.8). AK-FLUORŪ (fluorescein injection) is used intravenously as a diagnostic aid. The active ingredient exists as a sodium salt of fluorescein and is represented by the chemical structure: