Ferric Citrate Tablets Balancing Dissolution and Mechanical Strength

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Solution Overview

Problem

Existing ferric citrate formulations face challenges in achieving high dissolution rates and mechanical stability due to variations in molar ratios and hydration levels, leading to inconsistent performance in phosphate metabolism management and oral administration.

Innovation Solution

Development of ferric citrate tablets with controlled granule particle size and surface area, optimized binder and lubricant ratios, and a drying process to maintain high surface area per unit mass, resulting in rapid dissolution and improved mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If ferric citrate is prepared with varied molar ratios and hydration levels, then manufacturing flexibility is improved, but dissolution rate and mechanical stability deteriorate

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoiddissolution rate consistency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by establishing specific ranges for molar ratios (1:1 to 1:3 of Fe³⁺ to citrate) and hydration levels (0.5 to 2.0 water molecules per ferric citrate unit). These controlled parameter variations enable manufacturing flexibility while ensuring consistent dissolution rates and mechanical stability through defined compositional boundaries.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system where ferric citrate is combined with specific excipients including binders (1-10% w/w), disintegrants (5-20% w/w), and lubricants (0.5-5% w/w). This composite approach allows the formulation to maintain mechanical integrity and dissolution performance despite variations in ferric citrate composition.

Inventive Principle:
Principle #40Composite materials

2Strength

If ferric citrate tablet contains high binder content, then mechanical strength is improved, but dissolution rate deteriorates

Engineering Contradiction:
Improvemechanical strengthVSAvoiddissolution rate
Core Design Contradiction:
StrengthVSSpeed

Solution Approach 1:

The patent optimizes binder content within the specific range of 1-10% w/w of the total tablet weight. This parameter control ensures sufficient mechanical strength for tablet integrity while preventing excessive binder accumulation that would impede dissolution. The balanced formulation achieves both structural stability and rapid drug release.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs local quality by selecting binders with specific properties (water solubility, binding strength) that provide mechanical support only where needed in the tablet structure, while maintaining high dissolution rates in the ferric citrate active ingredient regions. This spatial differentiation of functions resolves the contradiction between strength and dissolution.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If ferric citrate tablet contains high lubricant content, then ease of tabletting is improved, but mechanical stability deteriorates

Engineering Contradiction:
Improveease of tablettingVSAvoidmechanical stability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent defines lubricant content within the precise range of 0.5-5% w/w of total tablet weight. This parameter optimization ensures adequate lubrication for smooth tabletting operations while preventing excessive lubricant that would compromise mechanical stability and tablet integrity during storage and handling.

Inventive Principle:
Principle #35Parameter changes

4Speed

If ferric citrate particle surface area is increased, then dissolution rate is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvedissolution rateVSAvoidmanufacturing complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The invention applies segmentation by utilizing granule particles with controlled surface area to mass ratio of at least 0.5 m²/g. This particle segmentation increases the total surface area available for dissolution without requiring complex manufacturing equipment or processes. The granulation approach naturally creates high-surface-area particles through simple granulating operations.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2456426B1Ferric citrate dosage forms
Publication Date: 2026.03.18 KERYX BIOPHARMACEUTICALS INC
  • EP2456426B1 patent drawingFigure 1
  • EP2456426B1 patent drawingFigure 2
  • EP2456426B1 patent drawingFigure 3

AI summary

The disclosure relates to ferric citrate tablets and dosage forms.