Metformin Hydrochloride Enteric Coating for pH-Dependent Release
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Solution Overview
Problem
Existing enteric-coated metformin hydrochloride preparations face contradictions in release characteristics, with some ensuring efficacy and safety through rapid release and others through slower release, lacking consistent clinical verification, and often result in adverse reactions and reduced bioavailability.
Innovation Solution
An enteric-coated preparation of metformin hydrochloride with specific drug release characteristics: dissolution rate not higher than 15% in pH 4.5 medium within 120 minutes and not lower than 85% in pH 6.8 medium within 20 minutes, maintaining gastrointestinal tolerance and hypoglycemic efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If enteric-coated preparation releases drug rapidly in intestinal fluid (pH 6.8), then hypoglycemic efficacy is ensured, but gastrointestinal adverse reactions increase
Solution Approach 1:
The patent applies parameter changes by precisely controlling the dissolution rate parameters: limiting dissolution in pH 4.5 medium to ≤15% within 120 minutes and ensuring dissolution in pH 6.8 medium reaches ≥85% within 20 minutes. This quantitative parameter control resolves the contradiction by optimizing the balance between maintaining efficacy and reducing gastrointestinal irritation.
Solution Approach 2:
The patent implements dynamics by creating a time-dependent release profile where the coating layer progressively dissolves at different rates under different pH conditions. The dynamic dissolution behavior adapts to the gastrointestinal environment, initially resisting dissolution in acidic stomach conditions then rapidly releasing the drug in the alkaline intestinal environment, thereby resolving the efficacy-safety contradiction.
2Object-affected harmful factors
If enteric-coated preparation delays drug release to reduce adverse reactions, then gastrointestinal tolerance improves, but bioavailability decreases
Solution Approach 1:
The patent uses parameter changes by optimizing the dissolution rate parameters to ensure that despite the delayed release mechanism, the drug achieves ≥85% dissolution in pH 6.8 medium within 20 minutes. This parameter optimization ensures sufficient bioavailability while maintaining the protective delayed-release function that improves gastrointestinal tolerance.
Solution Approach 2:
The enteric coating layer acts as an intermediary that mediates between the drug and the gastrointestinal environment. It protects the drug from premature release in the stomach while facilitating controlled release in the intestine, thereby improving tolerance without significantly compromising bioavailability through its optimized dissolution characteristics.
3Object-affected harmful factors
If enteric-coated preparation uses slower release rate, then adverse reactions are reduced, but clinical efficacy verification becomes inconsistent
Solution Approach 1:
The patent resolves the inconsistency by establishing specific dissolution rate parameters as quality standards: ≤15% dissolution in pH 4.5 within 120 minutes and ≥85% dissolution in pH 6.8 within 20 minutes. These quantified parameters provide consistent control over the release profile, ensuring both reduced adverse reactions and reliable clinical efficacy across different preparations.
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 preparation reduces adverse reactions and maintains hypoglycemic efficacy, improving patient compliance by allowing administration before, during, or after meals, with bioavailability comparable to immediate-release formulations.
Implementation Method 1
the dissolution rate of the biguanide compound in the enteric-coated preparation in a pH 4.5 medium within 120 minutes is not higher than 15%, and the dissolution rate of the biguanide compound in a pH 6.8 medium within 20 minutes is not lower than 85%
Data Source
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AI summary
The invention provides a new enteric-coated preparation of metformin hydrochloride, which is an oral dosage form made of a therapeutically effective amount of a biguanide compound and a pharmaceutically acceptable excipient, characterized in that the said enteric-coated preparation of metformin hydrochloride has a dissolution rate of no more than 15% in a pH 4.5 medium within 120 minutes, and a dissolution rate of no less than 85% in a pH 6.8 medium within 20 minutes, preferably a dissolution rate of no more than 7.5% in a pH 4.5 medium within 120 minutes, and a dissolution rate of no less than 85% in a pH 6.8 medium within 15 minutes. The enteric-coated preparation of metformin hydrochloride with the drug dissolution technical requirements of the present invention improves the gastrointestinal tolerance of metformin hydrochloride without reducing or even improving the hypoglycemic efficacy, reduces adverse reactions caused by the drug, and can be taken before, after or during meals, thereby improving the compliance of patients with medication.