Metformin Hydrochloride Enteric-Coated Tablets with pH-Triggered Release

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Solution Overview

Problem

Existing enteric-coated metformin hydrochloride preparations have inconsistent and unverified release characteristics, leading to contradictory efficacy and safety outcomes, with some causing rapid release that may reduce bioavailability and increase adverse reactions, while others provide sustained release that may not effectively target intestinal absorption, and clinical efficacy is often inaccurately measured.

Innovation Solution

A metformin hydrochloride enteric-coated tablet with specific drug release characteristics: dissolution rate not higher than 15% in pH 4.5 medium within 2 hours and not less than 85% in pH 6.8 medium within 20 minutes, achieved by controlling the onset dissolving point of the enteric coating material and weight gain in coating, ensuring rapid release in the intestine without excessive gastric release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If enteric-coated metformin hydrochloride preparations are designed to delay drug release in the stomach, then gastrointestinal adverse reactions are reduced, but the release characteristics become inconsistent and clinical efficacy is compromised

Engineering Contradiction:
Improvegastrointestinal adverse reactionsVSAvoidrelease characteristics consistency
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the dissolution rate parameters of the enteric coating: not more than 15% dissolution in pH 4.5 medium within 2 hours and not less than 85% dissolution in pH 6.8 medium within 20 minutes. These specific parameter ranges ensure consistent release characteristics while maintaining the enteric coating function to reduce gastrointestinal adverse reactions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent establishes a feedback mechanism through rigorous dissolution testing and quality control to verify that each batch of enteric-coated tablets meets the specified release parameters. This feedback loop ensures consistent release characteristics across production batches while maintaining the therapeutic efficacy and safety profile.

Inventive Principle:
Principle #23Feedback

2Productivity

If rapid release is achieved in intestinal fluid to ensure effective release, then bioavailability is improved, but gastrointestinal adverse reactions may increase

Engineering Contradiction:
Improvedrug release speedVSAvoidgastrointestinal adverse reactions
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating different dissolution rates at different locations (pH environments): slow dissolution in acidic stomach environment (pH 4.5, ≤15% in 2 hours) and rapid dissolution in neutral intestinal environment (pH 6.8, ≥85% in 20 minutes). This spatial differentiation of release characteristics ensures rapid intestinal release for bioavailability while preventing gastric release that causes adverse reactions.

Inventive Principle:
Principle #3Local quality

3Reliability

If sustained release is implemented to avoid toxic side effects, then safety is improved, but the drug may not effectively target intestinal absorption

Engineering Contradiction:
Improvesafety profileVSAvoidintestinal release efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by designing a time-dependent and pH-dependent release system: the enteric coating remains intact during gastric residence time, then rapidly dissolves upon encountering intestinal pH conditions. This dynamic response ensures the drug is released quickly when it reaches the absorption site, maintaining both safety and intestinal release efficiency.

Inventive Principle:
Principle #15Dynamics

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 tablet improves gastrointestinal tolerance and maintains hypoglycemic efficacy, reducing adverse reactions such as nausea and abdominal discomfort, and is bioequivalent to immediate-release formulations.

Implementation Method 1

the onset dissolving point of the enteric coating material is a pH value of 5.0 to 6.0

Methodology Applied
Scientific EffectpH-dependent solubility:

Implementation Method 2

the dissolution rate of metformin hydrochloride in a pH 6.8 medium within 20 minutes is not less than 85%

Methodology Applied
Scientific EffectpH-triggered dissolution:

Data Source

PatentEP4620459A1Metformin hydrochloride enteric-coated tablet
Publication Date: 2025.09.24 YAYAN (TIANJIN) BIOMEDICAL TECHNOLOGY CENTER (LLP)
  • EP4620459A1 patent drawingFigure 1~2
  • EP4620459A1 patent drawingFigure 3~4
  • EP4620459A1 patent drawingFigure 5~6

AI summary

The invention provides a metformin hydrochloride enteric-coated tablet, which is composed of a tablet core containing a therapeutically effective amount of metformin hydrochloride and an enteric coating layer wrapping the tablet core. The dissolution rate of metformin hydrochloride in a pH 4.5 medium within 2 hours is not higher than 15%, and the dissolution rate of metformin hydrochloride in a pH 6.8 medium within 20 minutes is not lower than 85%. The present invention obtains the metformin hydrochloride enteric-coated tablet with the specific drug release characteristics by controlling the disintegration time of the tablet core, the enteric coating material with the specific onset dissolving point and the weight gain in coating. Compared with the common metformin hydrochloride preparation (such as Glucophage) or the metformin hydrochloride enteric-coated tablet with other release characteristics, the tolerability and compliance of the metformin hydrochloride enteric-coated tablet said in the present invention are improved without reducing the hypoglycemic efficacy.