Biodegradable Antibiotic Thread for Osteomyelitis Treatment

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Solution Overview

Problem

Existing bead-shaped antibiotic release systems for treating osteomyelitis require a second procedure for removal, causing patient strain and additional costs, and often involve matrices that are difficult to produce or cause undesirable side effects due to degradation products.

Innovation Solution

A biodegradable thread with bead-shaped moldings of antibiotic salts like gentamicin palmitate or tobramycin stearate, pressed and annealed onto the thread without additional matrix formers, allowing for controlled release of antibiotics without a separate removal procedure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bead-shaped antibiotic release systems made of polymethyl methacrylate and zirconium dioxide are used, then the antibiotic release system is stable and effective, but a second procedure for removal is required causing patient strain and additional costs

Engineering Contradiction:
Improveantibiotic release effectivenessVSAvoidpatient burden from removal procedure
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the material parameters from non-biodegradable polymethyl methacrylate to biodegradable polyesters (polyglycolic acid, polylactic acid, poly-caprolactone). This parameter change allows the implant to degrade naturally in the body over time, eliminating the need for a second removal procedure while maintaining the antibiotic release function throughout the degradation period.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a disposable, biodegradable implant that performs its function and then naturally degrades without requiring removal. The bead-shaped carriers made of biodegradable polymers serve their antibiotic delivery purpose and then are safely metabolized by the body, similar to a disposable system that eliminates the need for recovery procedures.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Duration of action of moving object

If matrices such as polymethyl methacrylate are used for antibiotic incorporation, then the antibiotic release is controlled, but the matrices are difficult to produce or cause undesirable side effects due to degradation products

Engineering Contradiction:
Improvecontrolled antibiotic release durationVSAvoidmatrix production difficulty
Core Design Contradiction:
Duration of action of moving objectVSEase of manufacture

Solution Approach 1:

The patent changes the matrix material parameters from polymethyl methacrylate to biodegradable polyester polymers. These alternative materials offer comparable controlled release properties but with easier processing characteristics and biocompatible degradation products that are metabolized through natural physiological pathways, avoiding the harmful side effects of acrylic-based materials.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite bead structures combining biodegradable polyester matrices with antibiotic agents. The composite nature allows optimization of both drug release kinetics and material biocompatibility, using the polyester framework to control release while avoiding the manufacturing complexities and toxic degradation issues of traditional acrylic matrices.

Inventive Principle:
Principle #40Composite materials

3Duration of action of stationary object

If calcium sulfate is used as a matrix for antibiotic incorporation, then the antibiotic release system is biodegradable, but seroma formation is sometimes observed when larger amounts are implanted

Engineering Contradiction:
ImprovebiodegradabilityVSAvoidseroma formation
Core Design Contradiction:
Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the biodegradable matrix material from calcium sulfate to polyester polymers (polyglycolic acid, polylactic acid, poly-caprolactone). These polyester materials provide similar biodegradability but with different degradation kinetics and byproducts that do not trigger seroma formation, offering a safer alternative for larger implant volumes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs biodegradable polyester matrices that naturally degrade and are metabolized by the body without causing adverse reactions like seroma formation. The material serves its temporary drug delivery function and then safely disappears through natural physiological processes, avoiding the complications associated with calcium sulfate degradation.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 solution provides a stable, biodegradable antibiotic depot that avoids matrix-related issues, ensures controlled antibiotic release, and is metabolically safe, reducing the need for a second surgical intervention and minimizing side effects.

Implementation Method 1

pressed onto the biodegradable thread and then annealed at 50 - 70 ° C

Methodology Applied
Scientific EffectAnnealing: Annealing

Implementation Method 2

dissolved. The active ingredient is released by the action of blood or wound secretion

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 3

form pore systems from which the active ingredient can diffuse out

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP1820496B1Method of manufacturing a medical device for implantation
Publication Date: 2011.10.12 HERAEUS KULZER GMBH

AI summary

Form bodies (F1) comprises at least one member of the antibiotic salts (S1), gentamicin myristate, gentamicin palmitate, gentamicin stearate, tobramycin myristate, tobramycin palmitate, tobramycin stearate, amikacin myristate, amikacin palmitate, amikacin stearate, vancomycin palmitate, vancomycin stearate, ramoplanin palmitate, ramoplanin stearate, levofloxacin palmitate, levofloxacin stearate, ofloxacin palmitate, ofloxacin stearate, moxifloxacin palmitate, moxifloxacin stearate, clindamycin almitate or clindamycin stearate. Independent claims are included for the following: (1) medical device for implantation, comprising form bodies (F1) arranged on a biodegradable filament at a distance of 1-25 mm; and (2) manufacturing a device involving pressing form bodies of at least one antibiotic salt (S1) onto a filament and subsequently heat-treating at 50-70[deg]C.