Multilayer pH-Dependent Coating for Controlled Bicarbonate Release
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Solution Overview
Problem
Current pharmaceutical compositions fail to effectively release bicarbonate in the acidic environment of the stomach and duodenum, leading to uncontrolled and early release of active agents, which is not suitable for treating acid-base balance disturbances in the upper part of the small intestine.
Innovation Solution
A pH-dependent gradual sustained release pharmaceutical composition with a multilayer polymer coating, comprising cationic and anionic polymer layers, is developed to resist acidic pH and release bicarbonate in a controlled manner at pH 4.5 to 5.5, ensuring gradual and sustained release in the duodenum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple polymer coating is used to protect bicarbonate in the stomach, then the coating must be resistant to acidic pH, but this prevents controlled release in the duodenum where pH is only slightly acidic
Solution Approach 1:
The coating is divided into multiple functional layers: an inner enteric coating resistant to gastric acid that dissolves at duodenal pH, and an outer pH-dependent coating that dissolves at higher pH. This segmentation allows each layer to perform its specific function - protecting bicarbonate in the stomach while enabling controlled release in the duodenum
Solution Approach 2:
The patent uses a composite coating structure combining different polymer materials with distinct pH-dependent properties. The inner layer uses enteric polymers that dissolve at pH 5-6, while the outer layer uses pH-dependent polymers that dissolve at pH 6.5-7.5, creating a composite system that provides both gastric protection and controlled duodenal release
2Reliability
If bicarbonate is released early in the stomach, then the coating resistance is compromised, but this causes uncontrolled release and gas formation that worsens gastric distension
Solution Approach 1:
The enteric coating is designed to preemptively prevent bicarbonate release in the gastric environment by maintaining coating integrity at low pH. This preliminary protective action prevents the harmful reaction between bicarbonate and gastric acid that would cause uncontrolled gas formation and gastric distension
Solution Approach 2:
The pH-dependent outer coating layer acts as an intermediary that controls the timing and location of bicarbonate release. It prevents direct contact between the inner enteric coating and the gastric environment, allowing the system to maintain coating integrity while preparing for controlled release in the duodenum
3Quantity of substance
If the coating dissolves at low pH to release bicarbonate early, then bicarbonate availability increases, but this prevents targeted delivery to the duodenum where it is needed
Solution Approach 1:
The coating system provides different dissolution properties at different locations: the inner enteric coating dissolves specifically at duodenal pH (5-6) while remaining intact in the stomach, and the outer pH-dependent coating dissolves at higher pH in the jejunum. This local quality differentiation ensures bicarbonate is released exactly where needed in the upper small intestine
4Manufacturing precision
If a multilayer pH-dependent coating system is used to achieve controlled release, then release precision is improved, but the device complexity increases
Solution Approach 1:
The complex release profile is achieved by segmenting the coating into distinct functional layers, each with a specific pH dissolution threshold. This segmentation simplifies the manufacturing process compared to creating a single complex coating, as each layer can be applied and optimized independently to achieve the desired multi-stage release pattern
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 composition effectively increases the pH in the duodenum, alleviating acid load and preventing digestive disorders by providing bicarbonate directly to the duodenum, thus addressing bicarbonate deficiencies and promoting optimal digestion and absorption.
Implementation Method 1
the coating of the first type of microparticles is resistant to acidic pH below a well defined first pH threshold value but disrupts above this pH threshold value
Implementation Method 2
bicarbonate can be used orally for the neutralization of the gastric acid
Data Source
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AI summary
The invention concerns a pH-dependent gradual sustained release composition for increasing the pH in the upper part of the small intestines. Particles of the composition are provided with a multilayer polymer coating of specific structure which ensures the gradual release of the active agent in the range of pH 4.5 to 5.5. A process for preparing said composition is also claimed.