Benzimidazole-7-carboxylate Solid Composition pH Control

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Solution Overview

Problem

Benzimidazole derivatives, particularly compound (I), are unstable in neutral pH ranges commonly used for pharmaceutical preparations, leading to stability and solubility issues that affect their effectiveness and safety as hypertension therapeutic drugs.

Innovation Solution

A solid pharmaceutical composition comprising compound (I) and a pH control agent, such as monosodium fumarate or a combination of fumaric acid and sodium hydroxide, is developed to stabilize and improve the dissolution properties of compound (I) by adjusting the pH range to 2-5, enhancing its stability and solubility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If compound (I) is formulated in neutral pH range (common for pharmaceutical preparations), then the preparation is generally stable and safe, but compound (I) becomes unstable and decomposes

Engineering Contradiction:
Improvestability of compound (I)VSAvoiddecomposition of compound (I)
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the pH parameter of the preparation from neutral (common pharmaceutical range) to acidic range (pH 2-5). This parameter change stabilizes compound (I) by preventing decomposition, while the use of pH control agents ensures the preparation remains safe and effective for administration.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the pH is adjusted to stabilize compound (I), then stability improves, but solubility of compound (I) decreases

Engineering Contradiction:
Improvestability of compound (I)VSAvoidsolubility of compound (I)
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent introduces pH control agents (such as citric acid, tartaric acid, or their salts) as intermediary substances. These agents mediate between the conflicting requirements of stability and solubility by controlling the pH environment to maintain compound (I) stability while preventing excessive solubility loss through buffered acid-base equilibria.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If compound (I) has low solubility to maintain stability, then stability is improved, but dissolution property becomes slow affecting efficacy

Engineering Contradiction:
Improvestability of compound (I)VSAvoiddissolution speed of compound (I)
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent optimizes the pH parameter within the acidic range (pH 2-5) to find the optimal balance point where compound (I) maintains stability while achieving adequate dissolution speed. This parameter optimization ensures both stability and sufficient dissolution for therapeutic efficacy.

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 composition significantly stabilizes compound (I) and improves its dissolution properties, ensuring effective and safe drug delivery by maintaining optimal stability and solubility, as demonstrated through improved drug dissolution profiles and reduced decomposition.

Implementation Method 1

a pH control agent, having a pH of 2 to 5 and being monosodium fumarate or a combination of fumaric acid and sodium hydroxide

Methodology Applied
Scientific EffectpH control:

Implementation Method 2

adjusting the pH range of a solid preparation thereof to a pH range in which the solubility of compound (I) becomes low

Methodology Applied
Scientific EffectpH-dependent solubility:

Data Source

PatentEP2124903B1Solid pharmaceutical composition comprising a benzimidazole-7-carboxylate derivative and a ph control agent
Publication Date: 2019.06.12 TAKEDA PHARMA CO LTD
  • EP2124903B1 patent drawingFigure 1~2
  • EP2124903B1 patent drawingFigure 3

AI summary

The present invention provides a solid pharmaceutical composition containing compound (I) having an angiotensin II receptor antagonistic action and defined in the specification and a pH control agent, which composition is superior in the stability and dissolution property of compound (I).