Tiotropium Bromide Propionic Acid Crystalline Form

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Solution Overview

Problem

Tiotropium bromide, a potent anticholinergic for treating respiratory issues like COPD and asthma, requires stable and effective crystalline forms for inhalation administration, where the choice of excipient and particle size are critical for therapeutic efficacy, but existing forms face challenges in maintaining stability and reproducibility, especially at high temperatures.

Innovation Solution

A crystalline compound comprising Tiotropium bromide and propionic acid, with a molar ratio between 1:0.3 to 1:0.7, which forms a stable crystalline matrix that can be mixed with excipients, allowing precise particle size adjustment and maintaining effectiveness even at elevated temperatures, characterized by specific FT-Raman and XRPD patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If Tiotropium bromide is used in inhalable powder formulation with large amount of excipient, then the therapeutic efficacy is achieved at low doses, but the properties of the inhalable powder are significantly influenced by the choice of excipient and particle size

Engineering Contradiction:
Improveamount of excipientVSAvoidproperties of inhalable powder
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the crystalline form of Tiotropium bromide from known forms to a new crystalline form with specific lattice parameters and unit cell dimensions. This parameter change in the crystal structure results in improved properties such as lower moisture content, better flow characteristics, and reduced aerodynamic dispersion forces, thereby resolving the contradiction between using large amounts of excipient and maintaining reliable powder properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite crystalline structure by forming a crystalline compound comprising Tiotropium bromide and propionic acid in a specific molar ratio range (1:0.3 to 1:0.7). This composite crystalline form combines the properties of both components to achieve superior stability, lower moisture content, and improved flow characteristics compared to the parent compound alone

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If the crystalline form of Tiotropium bromide is used to ensure consistent quality, then the stability is improved, but the manufacturing process becomes more complex and less reproducible

Engineering Contradiction:
Improvecrystalline form stabilityVSAvoidmanufacturing process simplicity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent defines specific parameter ranges for the crystalline form including unit cell dimensions (a=5.321Å, b=9.026Å, c=13.307Å), space group (P21/n), and molar ratio of Tiotropium bromide to propionic acid (1:0.3 to 1:0.7). By establishing these precise parameters, the patent ensures consistent crystalline form and quality while providing clear manufacturing guidelines that improve reproducibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses propionic acid as an intermediary substance that forms a crystalline compound with Tiotropium bromide. This intermediary forms a stable crystalline matrix that facilitates the formation of the desired crystalline form during manufacturing, improving both stability and process reproducibility

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of substance

If micronised powder with low moisture content is used to prevent agglomeration, then the transmission into target area is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvemoisture contentVSAvoidparticle size control
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent changes the crystalline form of Tiotropium bromide to a new form with specific lattice parameters that inherently possess lower moisture content and improved flow characteristics. This parameter change in the crystal structure enables the powder to maintain low moisture content and appropriate particle size distribution more easily during manufacturing, reducing the stringency of manufacturing precision requirements

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 crystalline compound provides enhanced chemical and physical stability, allowing for effective storage and administration at high temperatures without decomposition, ensuring consistent quality and reproducibility in pharmaceutical compositions for inhalation.

Implementation Method 1

A crystalline compound comprising Tiotropium bromide and propionic acid, with a molar ratio between 1:0.3 to 1:0.7, which forms a stable crystalline matrix

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 2

maintaining effectiveness even at elevated temperatures, characterized by specific FT-Raman and XRPD patterns

Methodology Applied
Scientific EffectThermal stability:

Data Source

PatentEP2681211B1Crystalline compound comprising tiotropium bromide
Publication Date: 2015.10.07 BILGIC MAHMUT
  • EP2681211B1 patent drawingFigure 1~2
  • EP2681211B1 patent drawingFigure 3
  • EP2681211B1 patent drawing

AI summary

The present invention refers to a crystalline compound comprising a mixture of a compound of formula (I ) (Tiotropium bromide) and propionic acid, or a hydrate thereof, wherein the molar ratio of the compound of formula I and the propionic acid is in the range of from 1:0.3 to 1 :0.7 and a process for obtaining the same.