Silica Hydrogel Depot for Antiviral Sustained Release

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Solution Overview

Problem

Current treatments for chronic viral infections, such as Hepatitis B, require long-term daily administration of antiviral drugs, leading to patient compliance challenges and increased risk of drug resistance due to treatment breaks, and existing formulations are invasive and associated with systemic side effects.

Innovation Solution

A biodegradable silica hydrogel composite incorporating a nucleotide or nucleoside analogue reverse transcriptase inhibitor, designed to be non-flowing at rest but shear-thinning upon injection, allowing for minimally invasive, long-term delivery of antiviral drugs through a prefilled syringe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If daily oral self-administration or daily injections are used for antiviral drug therapy, then therapeutic effect is maintained, but patient compliance deteriorates due to strong commitment requirements and treatment burden

Engineering Contradiction:
Improvetherapeutic effectVSAvoidpatient compliance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The drug delivery system segments the total drug dose into controlled release portions through silica microparticles embedded in a hydrogel matrix, enabling sustained release over multiple weeks rather than requiring daily administration. This segmentation of delivery time points reduces patient burden while maintaining continuous therapeutic effect.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hydrogel composite is prepared in advance with encapsulated antiviral drugs in a controlled release formulation, allowing a single injection to provide sustained drug release over several weeks. This preliminary preparation eliminates the need for frequent patient visits and injections, significantly improving compliance while maintaining therapeutic reliability.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If treatment breaks occur due to patient compliance issues, then patient compliance improves temporarily, but drug resistance increases and recurrence is likely

Engineering Contradiction:
Improvepatient complianceVSAvoidtherapeutic effect
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The silica hydrogel composite provides continuous antiviral drug release over an extended period (several weeks) through controlled diffusion and degradation mechanisms. This continuous action eliminates treatment gaps that would otherwise occur with daily dosing, preventing drug resistance while maintaining patient compliance through reduced administration frequency.

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If frequent injections are administered to maintain therapeutic levels, then therapeutic effect is ensured, but patient compliance deteriorates due to invasive procedures

Engineering Contradiction:
Improvetherapeutic effectVSAvoidpatient compliance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The total drug delivery period is segmented into a single injection event that releases drug continuously over several weeks, rather than multiple injection events occurring daily or weekly. This temporal segmentation reduces the number of invasive procedures while maintaining continuous therapeutic drug levels through controlled release from the hydrogel matrix.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If long-term depot formulations are developed to reduce injection frequency, then patient compliance improves, but formulation complexity increases

Engineering Contradiction:
Improvepatient complianceVSAvoidformulation complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The formulation uses a composite system combining silica microparticles containing encapsulated antiviral drugs with a silica sol that forms a hydrogel network. This composite structure provides controlled drug release through multiple mechanisms (diffusion, degradation) while maintaining a relatively simple overall formulation that can be prepared and administered as a single injectable product, balancing complexity with extended release functionality.

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 silica hydrogel composite provides stable, long-term antiviral drug delivery with reduced side effects and improved patient compliance by enabling less frequent injections through thin needles, maintaining therapeutic levels for extended periods while minimizing burst release and immune reaction.

Implementation Method 1

said hydrogel composite is non-flowing and structurally stable when stored at rest and shear-thinning when shear stress is applied by injection

Methodology Applied
Scientific EffectShear-thinning: Shear Thinning

Implementation Method 2

Sol-gel derived silica microparticles with encapsulated drugs can be combined with a silica sol to form an injectable hydrogel depot composite for controlled delivery of antiviral drugs

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3365020B1Hydrogel composite depot formulation
Publication Date: 2019.07.17 DELSITECH
  • EP3365020B1 patent drawingFigure 1~2
  • EP3365020B1 patent drawingFigure 3~4
  • EP3365020B1 patent drawingFigure 5~6

AI summary

This invention relates to a depot formulation comprising a biodegradable silica hydrogel composite incorporating a nucleotide or nucleoside analogue reverse transcriptase inhibitor, wherein the silica hydrogel composite is obtainable by mixing silica particles comprising said nucleotide or nucleoside analogue reverse transcriptase inhibitor and having a maximum diameter of ≤ 1 000 μm, as such or as a suspension, with silica sol wherein the hydrogel composite is non-flowing and structurally stable when stored at rest and shear-thinning when shear stress is applied by injection. The present invention also relates to use of the depot formulation for treatment of chronic viral infections and prevention of chronic viral reinfection. The present invention further relates to a prefilled syringes comprising said depot formulation.