Leuprolide Microparticles With Controlled Release and Low Initial Burst

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Solution Overview

Problem

Current LHRH agonists like leuprolide acetate have a short half-life and require frequent administration due to rapid blood concentration decrease, leading to excessive initial release and potential side effects, necessitating the development of sustained-release formulations that maintain effective drug exposure.

Innovation Solution

Microparticles containing leuprolide and a biodegradable polymer with controlled release rates, uniform size distribution, and a weight ratio of 1:2 to 1:10, produced using a microchannel process to ensure sustained drug release for a month or more.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If leuprolide acetate is administered via conventional subcutaneous or intramuscular injection, then the drug can be delivered systemically, but the blood concentration decreases rapidly and the half-life is short, requiring frequent daily administration

Engineering Contradiction:
Improvehalf-lifeVSAvoidadministration frequency
Core Design Contradiction:
Duration of action of moving objectVSEase of operation

Solution Approach 1:

The drug is segmented into microparticles with specific size distribution (D10: 20-40 μm, D50: 40-60 μm, D90: 60-80 μm), where the segmented particle structure enables sustained release over 4 weeks or more while maintaining systemic delivery capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The microparticles are pre-formulated with controlled release characteristics before administration, creating a reservoir that gradually releases leuprolide acetate over an extended period, eliminating the need for frequent re-administration

Inventive Principle:
Principle #10Preliminary action

2Duration of action of moving object

If sustained release formulations are developed to reduce administration frequency, then the duration of action is extended to 4 weeks or more, but excessive release of leuprolide occurs at the initial stage when blood concentration is measured

Engineering Contradiction:
Improveduration of sustained releaseVSAvoidexcessive initial release
Core Design Contradiction:
Duration of action of moving objectVSObject-generated harmful factors

Solution Approach 1:

The particle size parameters are precisely controlled within specific ranges (D10: 20-40 μm, D50: 40-60 μm, D90: 60-80 μm) to optimize the balance between initial release rate and sustained release duration, preventing excessive initial release while maintaining therapeutic effectiveness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The release rate is made dynamic through the biodegradable polymer matrix, which gradually degrades over time to control drug release, allowing high initial release when needed followed by sustained lower-level release over 4 weeks or more

Inventive Principle:
Principle #15Dynamics

3Reliability

If leuprolide acetate is released rapidly at the initial stage to exhibit therapeutic effect, then the drug effect is achieved, but the blood concentration decreases rapidly afterward requiring daily administration

Engineering Contradiction:
Improvetherapeutic effectVSAvoidblood concentration maintenance
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The microparticle formulation ensures continuous drug release over 4 weeks or more through the gradual degradation of the biodegradable polymer matrix, maintaining therapeutic blood concentration levels without interruption or need for frequent re-administration

Inventive Principle:
Principle #20Continuity of useful action

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 microparticles provide controlled release of leuprolide, preventing excessive initial release, reducing side effects, and maintaining therapeutic effects for an extended period without daily administration.

Implementation Method 1

containing leuprolide and a biodegradable polymer

Methodology Applied
Scientific EffectBiodegradation: Decomposition (biological)

Data Source

PatentEP4420657B1Microparticles containing leuprolide, and preparation method thereof
Publication Date: 2026.02.18 INVENTAGE LAB INC
  • EP4420657B1 patent drawingFigure 1~2
  • EP4420657B1 patent drawingFigure 3~4
  • EP4420657B1 patent drawingFigure 5

AI summary

The present invention provides microparticles containing leuprolide and a method for producing the same. When the microparticles are administered by injection, they may lower pain due to their small size, control the release rate of leuprolide at a target site, prevent excessive release of leuprolide at an initial stage, enable exposure to a sufficient amount of the drug to exhibit the effect of leuprolide, and exhibit the effect of leuprolide for 1 month or more. The present invention also provides a method for producing microparticles, in which the microparticles have a uniform particle size and a smooth surface and may exhibit the effect of releasing leuprolide sustainably over a long period of time.