The objective of this study is to evaluate the efficacy of FST-201 compared to Ciprodex in the treatment of acute otitis externa. This trial is designed to enable filing of a New Drug Application in support of FST-201 for the indication of acute otitis externa.

Inclusion Criteria:

• Have a clinical diagnosis of AOE in one or both ears, defined as a clinical score of at least 1 for edema (0-3 scale), 2 for overall inflammation (0-3 scale) and 1 for tenderness (absent=0, present=1).
• Be at least 18 years of age at Visit 1 (Day 1, Screening/Baseline) of either sex and any race.
• Provide written informed consent or parental assent.
• Be willing and able to follow all instructions and attend all study visits

Exclusion Criteria:

All subjects must not:

• Have known sensitivity to any component of the study medications
• Have a current infection requiring systemic antimicrobial treatment
• Have used topical or systemic pain meds on the same day as Screening/Baseline Visit 1 and for the duration of the study.
• Take any systemic (within 30 days) or otic corticosteroids (within 1 days) prior to Screening/Baseline Visit 1
• Current use of topical or systemic non-steroidal or other anti-inflammatory drugs.
• Use any topical otic treatment with alcohol, vinegar, hydrogen peroxide or other astringent medication during the course of the study or on the same day as Screening/Baseline Visit 1
• Have taken any antibiotics within 3 days prior to Visit 1
• Have signs and symptoms of AOE for > 4 weeks at Screening/Baseline Visit 1
• Have a non-intact or perforated tympanic membrane in the enrolled ear
• Have a clinical diagnosis of chronic suppurative otitis media, acute otitis media or acute otorrhea in patients with tympanostomy tubes
• Have a clinical diagnosis of malignant otitis externa
• Have overt fungal AOE
• Have a viral infection of the pinna or tympanic membrane (i.e herpes zoster)
• Have congenital abnormalities of the external auditory canal in the enrolled ear(s)
• Have obstructive bony exostoses in the enrolled ear(s)
• Have mastoid or other suppurative, non-infectious ear disorders (e.g, cholesteatoma)
• Have malignant tumors of the external auditory canal
• Have a history of otologic surgery. Surgery performed more than 1 year prior to Screening/Baseline Visit 1and limited to the tympanic membrane is allowed
• Have seborrheic dermatitis of the external auditory canal
• Have a current or prior history of immunosuppressive disorders
• Have acute or chronic renal insufficiency, hepatitis or diabetes mellitus
• Be pregnant, nursing or planning a pregnancy.