Monolithic Polysaccharide Punctal Plugs for Sustained Drug Delivery

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Solution Overview

Problem

Current treatments for ocular pathologies face challenges in administering therapeutic agents in sufficient quantities and duration due to limited diffusion across the cornea and rapid depletion by ocular fluids, leading to high drug concentrations and side effects with frequent topical applications, while existing punctal plugs are short and require removal.

Innovation Solution

Development of a long, flexible, and erodible punctum plug made of high-molecular-weight polysaccharides with added plasticizers, capable of making a 90-degree turn within the canaliculus for controlled drug delivery and tear retention, allowing for a one-time use and easy removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If frequent topical applications of therapeutic agents are used, then sufficient drug concentration is achieved, but side effects increase and patient burden increases

Engineering Contradiction:

Improvedrug concentrationVSAvoidside effects

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The punctal plug is inserted beforehand to establish a controlled drug delivery system in the lacrimal drainage pathway. This preliminary action allows the drug to be released continuously over time, eliminating the need for frequent topical applications and reducing associated side effects while maintaining therapeutic efficacy

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The punctal plug acts as an intermediary device between the drug reservoir and the ocular surface. It controls and modulates drug delivery through the lacrimal drainage system, providing sustained release at therapeutic concentrations without the peaks and valleys associated with frequent topical dosing

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If existing short punctal plugs are used, then insertion is simple, but they require removal and do not provide sufficient retention

Engineering Contradiction:

Improveinsertion simplicityVSAvoidplug retention duration

Core Design Contradiction:

Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The punctal plug incorporates a hydrophilic section with specific local properties that enable it to interact with the lacrimal drainage system. This localized functional region provides anchoring through capillary action and hydrophilic interactions, allowing the plug to remain in place long-term without requiring removal while maintaining ease of initial insertion

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The plug utilizes changes in material properties, specifically the hydrophilic section's interaction with aqueous environments, to transition from a simple insertable device to a long-term retained implant. The parameter change in wettability and capillary action enables sustained retention without complicating the insertion procedure

Inventive Principle:

Principle #35Parameter changes

3Duration of action of moving object

If long punctal plugs are used to avoid anatomical bends, then tear retention is improved, but device complexity increases

Engineering Contradiction:

Improvetear retention durationVSAvoidplug structure complexity

Core Design Contradiction:

Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The punctal plug incorporates a flexible hydrophilic section that can bend and conform to the anatomical course of the lacrimal drainage system. This flexibility allows the long plug to navigate anatomical bends and turns while maintaining structural integrity, providing sustained tear retention without requiring complex rigid structures or multiple components

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The plug is constructed as a composite device with distinct sections having different properties: a hydrophobic section for insertion and a hydrophilic section for retention and drug delivery. This composite structure enables the long plug to achieve both anatomical compatibility and functional performance without increasing overall device complexity

Inventive Principle:

Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The punctum plug provides sustained drug delivery and tear retention, reducing the need for frequent applications and minimizing side effects by ensuring controlled release and easy removal, thus alleviating the burden on patients.

Implementation Method 1

capillary action and hydrophilic interactions, allowing the plug to remain in place long-term

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

capillary action and hydrophilic interactions, allowing the plug to remain in place long-term

Methodology Applied

Scientific EffectHydrophilic interaction: Hydrophile

Implementation Method 3

controlled release of a drug or non-active molecule to a desired ocular target tissue

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS12453653B2Materials and methods for punctal plugs

Publication Date: 2025.10.28 GLAUKOS CORP

AI summary

A punctum plug or lacrimal insert is constructed of a monolithic material, such that the punctum plug is configured to turn approximately 90 degrees upon insertion into a canaliculus of an eye. The punctum plug or lacrimal insert may include high-molecular-weight polysaccharide and added plasticizers.