Related Experiment Video
Updated: Jun 10, 2025
10:02
Use of Rabbit Eyes in Pharmacokinetic Studies of Intraocular Drugs
Published on: July 23, 2016
32.0K
A First-Passage Model of Intravitreal Drug Delivery and Residence Time-Influence of Ocular Geometry, Individual
Patricia Lamirande1, Eamonn A Gaffney1, Michael Gertz2
1Wolfson Centre for Mathematical Biology, Mathematical Institute, Andrew Wiles Building, University of Oxford, Oxford, United Kingdom.
Investigative Ophthalmology & Visual Science
|October 16, 2024
Summary
Mathematical modeling shows ocular drug residence time depends on eye size and injection site. This helps optimize intravitreal injection frequency for retinal disease treatments.
Area of Science:
- Ocular pharmacokinetics and drug delivery research.
- Biomedical engineering and mathematical modeling.
- Ophthalmology and retinal disease therapeutics.
Background:
- Recurrent intravitreal injections are standard for retinal diseases.
- Minimizing injection frequency requires understanding ocular drug residence time.
- Mathematical modeling can identify factors influencing drug disposition in the eye.
Purpose of the Study:
- To model vitreal diffusion of therapeutics in nonclinical species.
- To investigate the impact of ocular anatomy and injection site on drug disposition in human eyes.
- To identify factors influencing ocular drug residence time.
Main Methods:
- Utilized a first-passage time approach to model drug transport and elimination.
- Constructed 3D ocular geometries for multiple species (mouse, rat, rabbit, monkey, human).
- Derived a scaling relationship for comparing experimental ocular half-lives.
Main Results:
- Ocular drug residence time is dependent on eye size and injection location.
- Posterior vitreous delivery increased half-life and retinal permeation.
- Anterior exit was the primary elimination route; posterior pathway contribution varied by species.
Conclusions:
- Experimental variability in ocular half-life is linked to anatomical differences and injection sites.
- Posterior pathway permeability may explain species-specific pharmacokinetic differences.
- Modeling provides insights for optimizing intravitreal drug delivery strategies.
Related Concept Videos
01:22Drug Delivery: Miscellaneous Routes
329
Drug delivery methods like oral inhalation, nasal sprays, transdermal patches, eye drops, intravitreal injection, and rectal administration provide localized effects with reduced toxicity.
Oral inhalation and nasal sprays swiftly transfer drugs across the respiratory epithelium's mucosal layer. Inhaled glucocorticoids and bronchodilators directly target lung conditions such as asthma, while fluticasone nasal spray mitigates allergic rhinitis.
Transdermal patches transport drugs...
Oral inhalation and nasal sprays swiftly transfer drugs across the respiratory epithelium's mucosal layer. Inhaled glucocorticoids and bronchodilators directly target lung conditions such as asthma, while fluticasone nasal spray mitigates allergic rhinitis.
Transdermal patches transport drugs...
329
01:19One-Compartment Open Model for IV Bolus Administration: General Considerations
166
The one-compartment model is a pharmacokinetic tool that models the body as a single, uniform compartment, facilitating the understanding of drug distribution and elimination. This model is particularly beneficial for intravenous (IV) bolus administration, where the drug rapidly circulates throughout the body.
The drug's presence in the body is defined by an equation representing the difference between the rates of drug entry and exit. Key parameters—elimination rate constant,...
The drug's presence in the body is defined by an equation representing the difference between the rates of drug entry and exit. Key parameters—elimination rate constant,...
166
01:12One-Compartment Open Model for Extravascular Administration: Zero-Order Absorption Model
68
Extravascular administration, such as oral or intramuscular routes, is a non-invasive drug delivery method, often preferred for ease and patient compliance. A key factor here is absorption, which dictates how quickly and effectively the drug enters the bloodstream from the administration site. Absorption follows either zero-order or first-order kinetics.
Zero-order absorption maintains a steady rate irrespective of the amount of drug left to be absorbed, making it a constant process. In the...
Zero-order absorption maintains a steady rate irrespective of the amount of drug left to be absorbed, making it a constant process. In the...
68
01:15Non-Oral Extravascular Drug Absorption Routes
201
Non-oral extravascular routes, which encompass sublingual, buccal, topical, intramuscular, and inhalation methods, primarily utilize passive diffusion to transport drugs into the systemic circulation. The absorption rates and effectiveness of these routes depend on the drug's physicochemical properties, as well as the patient's anatomical and pathophysiological state.
Lipophilic drugs that are stable at salivary pH (6) and exhibit minimal binding to the oral mucosa are absorbed more...
Lipophilic drugs that are stable at salivary pH (6) and exhibit minimal binding to the oral mucosa are absorbed more...
201
01:16Drug Delivery: Overview
278
The selection of a drug's delivery route depends upon its physicochemical properties, including lipid or water solubility and ionization, as well as the therapeutic requirement, such as immediate or sustained effect. These routes can be divided into three primary categories: enteral, parenteral, and topical.
Enteral delivery involves administering drugs directly through swallowing, sublingual placement, or buccal application. Orally administered drugs predominantly navigate the...
Enteral delivery involves administering drugs directly through swallowing, sublingual placement, or buccal application. Orally administered drugs predominantly navigate the...
278
01:25Routes of Drug Administration: Parenteral
1.9K
The administration of drugs via parenteral routes allows for direct drug introduction into the systemic circulation, resulting in high bioavailability because the medication bypasses the harsh conditions of the gastrointestinal tract and hepatic metabolism.
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...
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...
1.9K