Fusidic Acid Crystalline Form Stability

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Solution Overview

Problem

Current solid forms of fusidic acid, such as the marketed hemihydrate, have stability and bioavailability issues due to polymorphism, affecting solubility, dissolution rate, and hygroscopicity, which impact its effectiveness in treating infectious diseases.

Innovation Solution

A novel crystalline form of fusidic acid is developed, characterized by specific Fourier Transform (FT)-NIR, FTIR-ATR, and X-ray powder diffraction spectra, offering improved stability and bioavailability through a controlled crystallization process involving solvents like acetonitrile and ethanol, resulting in a thermodynamically more stable anhydrous form.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the marketed hemihydrate form of fusidic acid is used, then it is available for clinical application, but it exhibits stability issues and bioavailability problems due to polymorphism

Engineering Contradiction:
ImprovestabilityVSAvoidbioavailability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by transforming fusidic acid from the hemihydrate solid form to an anhydrous crystalline form through controlled crystallization processes. This changes the physical and chemical parameters of the drug substance, resulting in improved stability while maintaining or enhancing bioavailability through optimized dissolution properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transitions by converting fusidic acid from a hydrated crystalline phase (hemihydrate) to an anhydrous crystalline phase. This phase transition eliminates the instability associated with the hemihydrate form while producing a more stable anhydrous form with improved pharmaceutical properties.

Inventive Principle:
Principle #36Phase transitions

2Productivity

If different crystal forms of fusidic acid are used, then solubility and dissolution rate can be optimized, but polymorphism causes variability in hygroscopicity and stability

Engineering Contradiction:
Improvedissolution rateVSAvoidhygroscopicity
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent employs parameter changes by systematically varying crystallization conditions (solvent type, temperature, concentration) to produce a specific anhydrous crystalline form of fusidic acid. This controlled parameter change results in a crystal form with optimized dissolution rate and reduced hygroscopicity compared to other polymorphic forms.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention converts the potential harm of polymorphism (which causes variability in hygroscopicity and stability) into a benefit by deliberately selecting and controlling the crystallization process to produce a specific anhydrous crystal form. This form eliminates the adverse effects of unwanted polymorphism while retaining the advantages of optimized dissolution and stability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the anhydrous crystalline form is produced through controlled crystallization, then stability and bioavailability are improved, but the process requires specific solvents and conditions

Engineering Contradiction:
ImprovestabilityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes phase transitions as the core mechanism for producing the anhydrous crystalline form. By controlling the phase transition from dissolved state to crystalline precipitate through systematic variation of crystallization parameters, the process achieves improved stability and bioavailability while maintaining operational simplicity.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The invention applies parameter changes in a controlled and systematic manner during crystallization. By adjusting parameters such as solvent composition, temperature, and concentration in a stepwise fashion, the process achieves the desired anhydrous crystal form without requiring overly complex equipment or procedures.

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 novel crystalline form exhibits enhanced stability and bioavailability, maintaining effectiveness in treating infectious diseases by optimizing solubility and dissolution rates, and can be converted back to the marketed hemihydrate form for specific applications.

Implementation Method 1

a novel crystalline form of fusidic acid and a process for the preparation of said crystalline fusidic acid

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP1945654B1Preparation of an antibiotic crystalline fusidic acid
Publication Date: 2015.08.19 LEO PHARMA AS
  • EP1945654B1 patent drawingFigure 1
  • EP1945654B1 patent drawingFigure 2
  • EP1945654B1 patent drawingFigure 3

AI summary

The present invention relates to processes for the crystallisation and for the preparation and isolation of a novel crystalline form of fusidic acid, to the use of said processes in the manufacture of pharmaceutical formulation or medicament, and to the use of said crystalline fusidic acid form for the treatment of bacterial infections.