Enteric Coating pH Gradient for Rapid Drug Release
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Solution Overview
Problem
Current enteric-coated dosage forms experience a discrepancy between in vitro and in vivo performance, leading to delayed drug release in the distal small intestine, which can result in ineffective therapy and reduced bioavailability due to the delay in releasing active substances at the optimal site of absorption in the upper small intestine.
Innovation Solution
A solid dosage form with an inner coating of partially neutralized anionic polymeric material and an outer enteric coating that is less or not neutralized, designed to disintegrate and release the drug earlier upon entry into the small intestine by creating a pH gradient, ensuring gastric resistance and rapid release at a lower pH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional enteric coatings with low dissolution threshold pH polymers are used, then rapid disintegration is achieved in in vitro tests, but delayed drug release occurs in vivo in the distal small intestine
Solution Approach 1:
The patent applies local quality by creating a pH gradient within the coating structure through selective neutralization. The inner coating layer is partially neutralized to pH 5.0-7.0 while the outer layer remains unneutralized or less neutralized, causing the coating to disintegrate at different pH thresholds in different regions. This enables the dosage form to release drug earlier in the small intestine (pH 5.5-6.5) rather than waiting for distal intestine (pH 6.8-7.4), thereby synchronizing in vitro rapid disintegration with in vivo timely drug release.
2Reliability
If enteric coatings are designed to resist dissolution in stomach, then gastric protection is achieved, but drug release is delayed until distal small intestine
Solution Approach 1:
The patent segments the enteric coating into two distinct functional layers: an inner partially neutralized coating layer that dissolves at lower pH (5.0-7.0) to enable early drug release in the proximal small intestine, and an outer unneutralized or less neutralized layer that provides gastric resistance (stable in pH 1.2-3.0). This segmentation allows the outer layer to protect the drug in the stomach while the inner layer triggers timely disintegration upon entering the small intestine, resolving the contradiction between gastric protection and timely drug release.
3Ease of manufacture
If uniform neutralization of enteric coating is applied, then simplified manufacturing is achieved, but inconsistent drug release performance occurs
Solution Approach 1:
The patent implements local quality by applying different neutralization degrees to different regions of the coating. The inner coating layer is partially neutralized to pH 5.0-7.0 while the outer layer remains unneutralized or less neutralized. This controlled spatial variation in neutralization degree ensures consistent drug release performance by creating a reliable pH gradient that triggers disintegration at the appropriate physiological pH, while still maintaining relatively simple manufacturing through sequential coating processes.
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 dosage form achieves less than 10% drug release in gastric fluid for at least 120 minutes and accelerates drug release at the intestinal pH, ensuring earlier release of the active substance when transferred from the stomach to the intestine, thereby improving bioavailability and therapeutic efficacy.
Implementation Method 1
In the intestine, the pH increases to 5 and above, allowing the carboxylic groups on the polymeric coating materials to ionize, and the polymer coatings to disintegrate or dissolve, releasing their contents.
Implementation Method 2
In the low pH environment of the stomach, the carboxylic groups remain un-ionized, and the polymer coatings remain insoluble.
Data Source
AI summary
The invention provides a gastric resistant, enteric-coated solid dosage form including a core containing a pharmaceutically active ingredient, an inner coating for the core, and an outer enteric coating. The inner coating comprises an anionic polymeric material or a water-soluble neutral polymeric material, and further comprises a water soluble inorganic salt which is not a carbonate or bicarbonates. The outer enteric coating comprises an anionic polymeric material which is less neutralized than the polymeric material comprising the inner coating and disintegrates rapidly at a pH of 5.5 to 7.0 upon entering the small intestine.