Composite Coating for Colon-Targeted Delayed Release Formulations
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Solution Overview
Problem
Existing drug formulations for delivering drugs to the colon face challenges such as premature drug release in the small intestine and excessive swelling of polysaccharide coatings, leading to inefficient drug delivery and potential drug loss in upper gastrointestinal regions.
Innovation Solution
A method involving a core coated with an outer layer containing an enzymatically degradable polymer, a film-forming enteric polymer with a pH threshold of about pH 6 or above, and an organic anti-tack agent, which enhances gastric resistance and facilitates faster drug release in the colon by utilizing colonic bacterial enzymes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polysaccharide coatings are used for colonic drug delivery, then the drug can be delivered to the colon via bacterial enzyme degradation, but the coating swells excessively in aqueous media leading to premature drug release in the upper gastrointestinal regions
Solution Approach 1:
The patent combines polysaccharide (enzymatically degradable polymer) with film-forming enteric polymer to create a composite coating. The polysaccharide provides colonic-specific degradation while the enteric polymer forms a stable film that prevents excessive swelling and premature drug release in upper GI regions, resolving the contradiction between reliable colonic delivery and drug loss prevention
Solution Approach 2:
The patent modifies the physical and chemical parameters of the coating system by controlling the molecular weight, degree of substitution, and composition ratio of polysaccharide and enteric polymer. These parameter changes optimize the coating's stability in aqueous media while maintaining enzymatic degradability in the colon, preventing premature release while ensuring targeted delivery
2Ease of operation
If polymer coatings dissolve or disintegrate at pH 5 or above to achieve small intestine release, then the drug is released in the small intestine, but this prevents targeted delivery to the colon
Solution Approach 1:
The patent changes the pH threshold parameter of the coating from pH 5 (small intestine release) to pH 6 or above (colon release). This is achieved by selecting enteric polymers with higher dissolution pH thresholds and adjusting the coating composition, thereby shifting the release location from small intestine to colon while maintaining a simple dissolution mechanism
Solution Approach 2:
The coating system automatically responds to the pH environment in the gastrointestinal tract, dissolving at pH 6 or above when it reaches the colon. The polymer's intrinsic pH-dependent solubility properties enable self-regulated drug release without additional complex mechanisms, achieving both ease of operation and reliable colonic targeting
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 method results in improved gastric resistance and faster drug release profiles in the colon, ensuring targeted drug delivery and minimizing drug loss in the upper gastrointestinal tract.
Implementation Method 1
a film-forming enteric polymer having a pH threshold of about pH 6 or above
Implementation Method 2
an enzymatically degradable polymer which is degradable by colonic bacterial enzymes
Data Source
AI summary
A method produces a coatable core for a delayed release drug formulation for oral administration, to deliver a drug to the colon. The method involves forming a core containing a drug. An outer layer coating preparation is formed by combining a first aqueous preparation of an enzymatically degradable polymer, which is degradable by colonic bacterial enzymes; a second aqueous preparation of a film-forming enteric polymer having a pH threshold of about pH 6 or above; and an organic anti-tack agent. The core is then coated with the outer layer coating preparation to form an outer layer coated core.