PLGA Microspheres for Chronic Pain Release Kinetics

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Solution Overview

Problem

Current local anesthetic delivery systems are ineffective for managing chronic postoperative pain, as they fail to provide sustained relief beyond a few days and lack optimization of drug dosing and release kinetics.

Innovation Solution

Biodegradable microspheres composed of poly(lactic-co-glycolic acid) with a 75:25 ratio of polylactic acid to glycolic acid, loaded with 60% bupivacaine, designed to release 75% of the anesthetic within 72 hours and 80-90% within 120 hours, providing linear release kinetics for at least 28 days, thereby addressing chronic pain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If local anesthetics are used through continuous infusion or slow release materials, then the duration of pain relief is extended, but the optimization of drug dosing and release kinetics is insufficient for chronic pain management

Engineering Contradiction:

Improveduration of pain reliefVSAvoideffectiveness for chronic pain

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent optimizes the release kinetics parameters by controlling the polymer composition (PLGA 75:25 ratio), microsphere size (65-75 micrometers), and drug loading concentration (60% bupivacaine) to achieve linear release over 28 days, transforming the delivery system from insufficient slow release to optimized chronic pain management

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite formulation combining biodegradable PLGA polymer with bupivacaine local anesthetic in specific ratios, creating a sustained-release microsphere system that maintains effective drug concentrations for chronic pain treatment beyond the limitations of single-material approaches

Inventive Principle:

Principle #40Composite materials

2Duration of action of moving object

If biodegradable polymer microspheres are used to slowly release local anesthetic, then the duration of action is extended, but uniform distribution and controlled release kinetics are difficult to achieve

Engineering Contradiction:

Improveduration of drug releaseVSAvoiduniform distribution of drug

Core Design Contradiction:

Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The patent achieves uniform distribution by precisely controlling manufacturing parameters including polymer molecular weight, drug loading concentration (60%), microsphere size (65-75 micrometers), and solvent composition, transforming the formulation from non-uniform to uniformly distributed drug-polymer composite

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent ensures homogeneous distribution of bupivacaine throughout the PLGA matrix at the molecular level, creating uniform local drug concentration across all microspheres, which enables predictable and consistent release kinetics throughout the 28-day treatment period

Inventive Principle:

Principle #3Local quality

3Duration of action of moving object

If high concentration of local anesthetic is loaded in microspheres, then the duration of pain relief is extended, but initial burst release occurs reducing control

Engineering Contradiction:

Improveduration of pain reliefVSAvoidcontrol of release kinetics

Core Design Contradiction:

Duration of action of moving objectVSStability of the object's composition

Solution Approach 1:

The patent achieves linear release kinetics by optimizing the polymer-to-drug ratio, using PLGA 75:25 composition with 60% bupivacaine loading, and controlling microsphere physical parameters to eliminate burst release while maintaining 28-day duration of action

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the porous structure of PLGA microspheres with controlled porosity to regulate drug diffusion, allowing sustained release of high concentrations of bupivacaine without initial burst, achieving both extended duration and controlled kinetics through the polymer matrix structure

Inventive Principle:

Principle #31Porous 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 microspheres effectively relieve chronic pain for at least 28 days by maintaining a consistent release of bupivacaine, inhibiting ionic sodium channels in local neurons, and avoiding initial burst release, thus optimizing pain management.

Implementation Method 1

the bupivacaine is released linearly for the first 120 hours

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

the at least one biodegradable polymer is poly(lactic-co-glycolic acid)

Methodology Applied

Scientific EffectBiodegradation: Decomposition (biological)

Implementation Method 3

inhibiting ionic sodium channels in local neurons

Methodology Applied

Scientific EffectIon channel blocking:

Data Source

PatentEP3000463B1Drug loaded microspheres for post-operative chronic pain

Publication Date: 2020.12.09 COVIDIEN LP

Figure 1A~2B
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Figure 5~6B

AI summary

A microsphere is disclosed. The microsphere includes at least one biodegradable polymer and at least one local anesthetic, wherein about 75% of the at least one local anesthetic is released by about 72 hours and from about 80% to about 90% of the at least one local anesthetic is released by about 120 hours, thereby relieving chronic pain for at least 28 days.