Related Experiment Video
Updated: Jun 8, 2026

High-throughput Screening of Chemical Compounds to Elucidate Their Effects on Bacterial Persistence
Published on: February 23, 2021
Comparison of systemic and otic administration of ofloxacin
Elena Koulich1, Peter S Roland, Karen S Pawlowski
1Department of Otolaryngology HNS, University of Texas Southwestern Medical Center, Dallas UT Southwestern, Dallas, Texas 75390-9035, USA. Elena.Koulich@utsouthwestern.edu
Objectives:
To assess the feasibility of delivering ofloxacin across the intact tympanic membrane; to compare middle ear bioavailability of ofloxacin after otic and systemic administrations; to determine distribution of otically delivered ofloxacin to other tissues.
Study Design:
A prospective, controlled animal study.
Methods:
Rats underwent surgery wherein the middle ear cavity was opened and filled with saline. An equivalent amount of ofloxacin was delivered intraperitoneally or into the external ear canal. Saline within the middle ear was sampled and completely replaced in 15-minute intervals for 3 hours. Blood was collected twice after the initial application of ofloxacin for high-performance liquid chromatography (HPLC). Animals were sacrificed 3 hours after the initial addition of ofloxacin; the temporal bones were harvested for histological analysis; urine and colon mucosa were collected for HPLC analysis.
Results:
Both systemic and otic applications led to a comparable accumulation of ofloxacin in the middle ear over the 3-hour period after the initial administration. The pharmacokinetics of ofloxacin penetration into the middle ear was sporadic and subject-dependent. Both methods of administration led to drug accumulation in blood serum, urine, and colonic mucosa.
Conclusions:
Topical application of ofloxacin to the intact tympanic membrane allows for drug penetration into the middle ear space. Similar middle ear ofloxacin levels could be achieved with systemic and topic applications, but drug concentrations were inconsistent. The accumulation of ofloxacin in other tissues suggests applications designed to be ototopical may also result in systemic absorption.
Related Concept Videos
Ophthalmic Drug Delivery Systems
Dosage Interval and Administration Route: Determination Methods
Pharmaceutical Alternatives: Stability-Related Therapeutic Nonequivalence
Routes of Drug Administration: Overview
Enteral administration refers to drugs absorbed through the gastrointestinal tract. They can be swallowed (perorally), placed under the tongue (sublingually), or on the inner lining of the cheeks (buccally). Perorally administered drugs take time to be absorbed and have a slower onset of action. The rectal route is another form of enteral administration, which allows for...
Inhibitors of Bacterial DNA Synthesis
Routes of Drug Administration: Parenteral
The intravenous route (IV) of drug administration can be further categorized into two types. The bolus injection administers the entire dose rapidly, while an intravenous infusion slowly delivers smaller doses steadily.
The IV route is often...

