Ligand-Modified Ferric Iron Phosphate Binders

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Solution Overview

Problem

Current phosphate binders for hyperphosphatemia, such as aluminum, calcium, and iron compounds, face issues like toxicity, non-specific binding, gastrointestinal side-effects, and low patient compliance, with existing materials having limitations in efficacy and safety.

Innovation Solution

Development of ligand-modified ferric poly oxo-hydroxy materials, specifically ferric iron compositions with carboxylic acid ligands like adipate, which form a solid phase with reproducible physico-chemical properties for enhanced phosphate binding and removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If aluminium-based phosphate binders are used to bind dietary phosphate, then phosphate binding efficacy is improved, but tissue accumulation and systemic toxicity occur

Engineering Contradiction:
Improvephosphate binding capacityVSAvoidtissue accumulation and systemic toxicity
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical parameters of the binder by using ferric iron oxo-hydroxides with controlled particle size, surface area, and surface chemistry characteristics. These parameter changes enable effective phosphate binding while avoiding the toxic accumulation associated with aluminium-based binders, as iron is better tolerated by the body.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs composite material characteristics by creating ferric iron oxo-hydroxide materials with specific surface modifications and controlled physical properties. This composite approach allows the material to achieve both high phosphate binding capacity and improved safety profile compared to pure aluminium compounds.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If large quantities of calcium-based phosphate binders are administered to bind phosphate, then phosphate binding efficacy is improved, but hypercalcemia and tissue calcification are aggravated

Engineering Contradiction:
Improvephosphate binding capacityVSAvoidhypercalcemia and tissue calcification
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The invention changes from calcium-based to iron-based materials, fundamentally altering the chemical composition parameter. Ferric iron oxo-hydroxides provide effective phosphate binding without contributing to hypercalcemia or calcium-based tissue calcification, directly resolving the harmful effects associated with calcium binder overuse.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If sevelamer is used to bind dietary phosphate, then phosphate binding occurs, but non-specific binding requires large doses leading to low patient compliance

Engineering Contradiction:
Improvephosphate binding capacityVSAvoidpatient compliance
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The invention optimizes the physical and chemical parameters of the iron oxo-hydroxide material, specifically controlling particle size distribution, surface area, and surface chemistry. These parameter changes enhance phosphate binding efficiency per unit mass, reducing the total dose required and thereby improving patient compliance compared to non-specific binders like sevelamer.

Inventive Principle:
Principle #35Parameter changes

4Quantity of substance

If soluble iron compounds are used to bind phosphate, then phosphate binding efficacy is improved, but gastrointestinal side-effects occur due to redox activity

Engineering Contradiction:
Improvephosphate binding capacityVSAvoidgastrointestinal side-effects
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The invention utilizes the phase transition from soluble to insoluble form by employing ferric iron oxo-hydroxides, which are insoluble materials. This phase change eliminates the redox activity problems associated with soluble iron compounds, as the insoluble form does not release free iron ions in the gastrointestinal tract, thereby preventing gastrointestinal side-effects while maintaining phosphate binding efficacy.

Inventive Principle:
Principle #36Phase transitions

5Quantity of substance

If existing phosphate binders are used, then phosphate binding occurs, but limitations in efficacy and safety prevent ideal treatment

Engineering Contradiction:
Improvephosphate binding capacityVSAvoidsafety and efficacy
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The invention systematically optimizes multiple parameters of the iron-based binder including particle size, surface area, surface chemistry, and crystallinity. These parameter changes collectively enhance both the efficacy (phosphate binding capacity) and reliability (safety profile) of the treatment, overcoming the limitations of existing phosphate binders.

Inventive Principle:
Principle #35Parameter changes

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 ligand-modified ferric iron compositions demonstrate superior phosphate binding capacity and safety, effectively reducing serum phosphate levels with improved patient compliance and reduced side-effects compared to existing treatments.

Implementation Method 1

The ability to bind phosphate by iron oxo-hydroxides is known in the art... ferric iron compositions... can bind phosphate in in vitro and in in vivo studies

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP2320884B1Phosphate binding materials and their uses
Publication Date: 2016.07.13 MEDICAL RESEARCH COUNCIL
  • EP2320884B1 patent drawingFigure 1
  • EP2320884B1 patent drawingFigure 2a~2b
  • EP2320884B1 patent drawingFigure 3~4

AI summary

Phosphate binding materials and compositions comprising them which are solid ligand-modif ied poly oxo-hydroxy metal ion materials are disclosed that are based on ferric iron oxo- hydroxides modified with carboxylic acid ligands, or ionised forms thereof. These materials are made and tested in the examples provided in the application to demonstrate that they can bind phosphate in in vitro and in in vivo studies.