Salt Forms for Pulmonary Drug Stability

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Solution Overview

Problem

Current pharmaceutical formulations of 4-(dimethylamino)butyl 2-(4-((2-amino-4-methyl-6-(pentylamino)pyrimidin-5-yl)methyl)phenyl)acetate lack stability and suitable form for pulmonary or nasal administration, requiring improvement in chemical and physical stability and particle size for effective delivery.

Innovation Solution

Development of disaccharin, difumaric acid, di-1-hydroxy-2-naphthoic acid, and benzoic acid salts that form crystalline materials with enhanced stability and crystallinity, allowing for formulation as a dry powder with a high fine particle fraction for deep lung delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the active compound is formulated for pulmonary administration, then deep lung delivery and absorption are enhanced, but chemical and physical stability during storage deteriorates

Engineering Contradiction:
Improvepulmonary delivery efficiencyVSAvoidchemical and physical stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by converting the active compound into salt forms with different physicochemical properties. Specifically, salts such as the disaccharin salt, difumaric acid salt, di-1-hydroxy-2-naphthoic acid salt, and benzoic acid salt are prepared, each exhibiting improved stability characteristics compared to the free base form. This chemical form modification allows the compound to maintain stability during storage while still enabling effective pulmonary delivery when administered.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material strategies by formulating the active compound salts with carrier materials suitable for pulmonary administration. The stable salt forms can be combined with inhalation-grade carriers to create dry powder formulations that maintain both stability during storage and deliverability to deep lung regions, thus resolving the contradiction between stability and ease of pulmonary operation.

Inventive Principle:
Principle #40Composite materials

2Productivity

If the active compound is micronised to achieve high fine particle fraction, then deep lung absorption is increased, but manufacturing complexity and processing difficulty increase

Engineering Contradiction:
Improveabsorption rateVSAvoidmicronisation process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-converting the active compound into stable salt forms before the micronisation process. This preliminary chemical transformation improves the compound's properties (such as flow characteristics and crystallinity), which in turn facilitates the subsequent micronisation process and reduces its complexity. The stable salts can be more readily processed into fine particle fractions suitable for deep lung delivery without requiring overly complex manufacturing steps.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If stable crystalline forms are obtained, then handling and shelf-life are improved, but formulation flexibility is reduced

Engineering Contradiction:
Improveshelf-lifeVSAvoidformulation flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent demonstrates universality by developing multiple different salt forms of the active compound (disaccharin salt, difumaric acid salt, di-1-hydroxy-2-naphthoic acid salt, benzoic acid salt). Each of these salt forms provides stable crystalline characteristics that improve handling and shelf-life, while the variety of salt options maintains formulation flexibility. Different salts can be selected based on specific formulation requirements, thus achieving both reliability and adaptability.

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

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 salts exhibit improved solid-state chemical stability under high temperature and humidity conditions and maintain stability when mixed with common carriers like lactose, enabling effective storage and enhanced absorption through deep lung delivery.

Implementation Method 1

Development of disaccharin, difumaric acid, di-1-hydroxy-2-naphthoic acid, and benzoic acid salts that form crystalline materials with enhanced stability and crystallinity

Methodology Applied
Scientific EffectCrystallisation: Crystallisation

Data Source

PatentEP2435412B1Saccharin, fumaric acid, 1-hydroxy-2-naphthoic acid and benzoic acid salts of 4-(dimethylamino)butyl 2-(4-((2-amino-4-methyl-6-(pentylamino)pyrimidin-5-yl)methyl)phenyl)acetate
Publication Date: 2016.01.27 SUMITOMO PHARMA CO LTD
  • EP2435412B1 patent drawingFigure 1
  • EP2435412B1 patent drawingFigure 2
  • EP2435412B1 patent drawingFigure 3

AI summary

The invention provides salts of 4- (dimethylamino) butyl 2- (4- ( (2-amino-4-methyl-6- (pentylamino) pyrimidin-5-yl ) methyl ) phenyl ) acetate (compound (I)), pharmaceutical compositions containing them and their use in therapy.