Adjustable Capillary Drug Delivery for Bone Fractures

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Solution Overview

Problem

Existing drug delivery systems for treating bone fractures are limited by the inability to replace active ingredients, require complex removal, and have inefficient drug release profiles, leading to high financial and treatment costs for periprosthetic infections.

Innovation Solution

A device comprising capillaries with removable cores, an intermediate piece, and a guide system that allows for the localized and adjustable application of pharmaceutical fluids, enabling easy insertion and removal without damaging bone tissue, and allowing for repeated drug delivery over several hours to days.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional drug carriers (non-absorbable or absorbable sponges) are used for local antibiotic application, then the active ingredient is delivered to the fracture site, but the active ingredient cannot be replaced or supplemented once implanted and the drug release is limited by diffusion principles

Engineering Contradiction:
Improveability to replace or supplement active ingredientVSAvoidcomplexity of removal and reapplication
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The device is divided into separate components: a removable capillary containing the active ingredient, a carrier body, and a closure system. This segmentation allows the capillary to be removed and replaced with a new one containing different antibiotics, enabling adaptation without removing the entire implant system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The capillary is inserted into the carrier body, forming a nested structure where the capillary (inner element) can be independently removed and replaced while the carrier body remains in place. This nested design simplifies the replacement process compared to complete system removal.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Duration of action of moving object

If drug release is based on diffusion through solid carriers, then the drug is delivered passively, but large amounts of active ingredient are only released in the first few hours

Engineering Contradiction:
Improveduration of drug releaseVSAvoidamount of active ingredient released
Core Design Contradiction:
Duration of action of moving objectVSQuantity of substance

Solution Approach 1:

The system transitions from passive diffusion to active controlled release by introducing a liquid carrier medium that can be dynamically introduced and pressurized. This allows the active ingredient to be released on demand over extended periods rather than relying solely on concentration gradients.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A liquid carrier medium is introduced into the carrier body and pressurized to force the active ingredient through the capillary walls and into the fracture site. This hydraulic mechanism enables controlled, sustained release of large quantities of drug over multiple days.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Ease of operation

If complex removal procedures are used for traditional drug carriers, then complete removal of implant material is achieved, but surgical intervention and treatment time are increased

Engineering Contradiction:
Improveease of removalVSAvoidsurgical intervention time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The capillary containing the active ingredient is designed to be extractable from the carrier body through a simple withdrawal motion. This allows the drug reservoir to be replaced without removing the entire implant system, significantly reducing surgical intervention time.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The capillary is pre-loaded with active ingredient before implantation. Once implanted, only the capillary needs to be accessed and replaced, not the entire system. This preliminary preparation simplifies subsequent maintenance and drug replacement procedures.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If non-absorbable or absorbable drug carriers are implanted, then local antibiotic delivery is achieved, but the treatment cannot be adapted during the healing process

Engineering Contradiction:
Improveability to adapt treatment protocolVSAvoidcomplexity of system structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The carrier body serves multiple functions: it houses different capillaries containing various antibiotics, provides structural support, and enables repeated drug delivery. This multi-functionality allows adaptation of treatment protocols without requiring completely different implant systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system transitions from a static, fixed-composition carrier to a dynamic system where the active ingredient can be changed by replacing capillaries. This dynamic capability allows treatment adaptation based on healing progress and infection status.

Inventive Principle:
Principle #15Dynamics

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

Enables localized and adjustable drug delivery directly to bone fractures, preventing microbial colonization, reducing treatment complexity, and minimizing surgical intervention, while allowing for easy removal and adaptation of treatment protocols.

Implementation Method 1

The capillary (1) allows for the conveyance of a pharmaceutical fluid into the fracture

Methodology Applied
Scientific EffectLiquid flow through capillary:

Implementation Method 2

a manually removable core (9) arranged in the cavity of the at least one capillary (1) and the intermediate piece (5), which closes at least 50% of the cross-sectional area of the at least one opening (2) of the at least one capillary (1)

Methodology Applied
Scientific EffectPhysical occlusion:

Data Source

PatentEP3831426B1Device for local application of pharmaceutical fluids
Publication Date: 2025.07.09 HERAEUS MEDICAL GMBH
  • EP3831426B1 patent drawingFigure 1
  • EP3831426B1 patent drawingFigure 2
  • EP3831426B1 patent drawingFigure 3

AI summary

The invention relates to a device for the local application of pharmaceutical fluids, the device comprising at least one capillary (1) with at least one opening (2) in the region of the distal end (3) of the at least one capillary (1), a hollow intermediate piece (5) which is permeably connected to the at least one capillary (1), a guide (6) for guiding the intermediate piece (5) which has a distal support (7) for resting on the patient, and a fixing element (8) for fixing the intermediate piece (5) to the guide (6), wherein the fixing element (8) allows the intermediate piece (5) to be fixed in various positions relative to the guide (6), and the fixing prevents displacement of the intermediate piece (5) relative to the guide (6). The invention also relates to a method for preparing such a device.