Andrographolide Micropellets for IBD Colon Targeting
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Solution Overview
Problem
Current treatments for inflammatory bowel disease (IBD), particularly Crohn's disease, lack effective medications with minimal side effects, and existing colon-targeting drug delivery systems face challenges in ensuring drug release at the correct pH levels in the colon due to individual pH variations and instability of enzyme-degraded polymers.
Innovation Solution
Development of an andrographolide enteric targeting micropellet using a dual pH-dependent polymer system, comprising a drug layer with Eudragit S100 and an enteric coating layer with Eudragit L100-55, to achieve controlled release of andrographolide in the colon, ensuring effective treatment of IBD by maintaining the integrity of the polymer membrane and optimizing drug delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single pH-dependent polymer is used for enteric coating, then the drug can be protected from release in the stomach, but the drug may not release at the correct pH level in the colon due to individual pH variations
Solution Approach 1:
The enteric coating system is segmented into two distinct polymer layers: an outer layer comprising Eudragit L100-55 (pH-dependent polymer) and an inner layer comprising Eudragit S100 (pH-independent polymer). This segmentation allows each layer to perform its specific function - the outer layer provides pH-dependent dissolution protection while the inner layer ensures consistent drug release regardless of pH variations, thereby resolving the contradiction between reliability and adaptability.
Solution Approach 2:
The invention uses a composite coating structure combining two different polymer materials with complementary properties. Eudragit L100-55 provides pH-dependent solubility (dissolves at pH≥5.5) while Eudragit S100 provides pH-independent solubility and structural integrity. This composite material approach creates a coating system that is both reliable in protecting the drug in the stomach and adaptable to ensure release in the colon despite individual pH variations.
2Ease of operation
If enzyme-degraded polymers are used for colon targeting, then the drug can be delivered to the colon, but the polymer membrane stability is compromised leading to premature drug release
Solution Approach 1:
The invention extracts and removes the enzyme-degraded polymer component from the coating system and replaces it with pH-dependent polymers (Eudragit L100-55 and Eudragit S100) that are not susceptible to enzymatic degradation. This extraction eliminates the stability problem associated with enzyme-degraded polymers while maintaining the colon-targeting capability through pH-dependent dissolution in the colonic environment.
Solution Approach 2:
The invention changes the degradation parameter from enzyme-dependent to pH-dependent. Instead of relying on enzymatic breakdown which compromises membrane stability, the system uses the pH gradient along the gastrointestinal tract as the triggering parameter for drug release. The Eudragit L100-55 remains stable in the acidic stomach environment and only dissolves at the higher pH of the colon, ensuring both stable membrane integrity and targeted delivery.
3Reliability
If conventional enteric coatings are used, then the drug is protected in the stomach, but the coating may dissolve prematurely in the small intestine due to pH variations among individuals
Solution Approach 1:
The invention introduces a dynamic, multi-layer coating structure where the outer Eudragit L100-55 layer dynamically responds to pH changes by remaining intact in the stomach and dissolving in the colon, while the inner Eudragit S100 layer provides a stable matrix that dynamically releases the drug in response to the outer layer's dissolution. This dynamic structure ensures precise release location control despite individual pH variations in the small intestine.
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 andrographolide enteric targeting micropellet effectively reduces colon inflammation, adhesion, and ulceration, demonstrating improved therapeutic efficacy and stability in treating IBD by ensuring controlled drug release at the appropriate pH levels, thus overcoming the limitations of previous delivery systems.
Implementation Method 1
said enteric coating layer contains the polymer B dissolved under a condition of pH≧5.5
Implementation Method 2
said drug layer contains the andrographolide, a polymer A dissolved under a condition of pH≧7.0
Data Source
AI summary
The present invention relates to an andrographolide enteric targeting micropellet and a method for preparation thereof; furthermore, the present invention also relates to uses of andrographolide and andrographolide enteric targeting micropellets in preparation of a pharmaceutical for treatment of inflammatory bowel disease.