Delayed Release Drug Formulation Isolation Layer
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Solution Overview
Problem
Current delayed release formulations for targeting the colon face challenges in achieving rapid drug release, as existing coatings do not effectively accelerate drug release in the intestinal environment, leading to prolonged lag times and inefficient drug delivery.
Innovation Solution
Incorporating an isolation layer between the core and the outer coating, comprising a pH dependently soluble polymeric material and a soluble polymeric material that is soluble in intestinal fluid, which accelerates initial drug release by creating a fluid region that facilitates dissolution and disintegration of the outer layer, thereby speeding up drug release from the core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pH dependent polymeric coating is used to target the colon, then the drug is protected from release in the small intestine, but the drug release in the colon is delayed due to prolonged lag time
Solution Approach 1:
The coating is divided into multiple functional layers: an inner layer containing pH dependent polymeric material (e.g., Eudragit L or S) for colon targeting, and an outer layer containing soluble polymeric material (e.g., HPMC, PVA, or PVP) that accelerates drug release. This segmentation allows each layer to perform its specific function - the inner layer ensures delayed release until colon arrival, while the outer layer accelerates dissolution once in the intestinal environment, thereby reducing lag time without compromising targeting accuracy.
2Productivity
If the outer coating layer dissolves rapidly in intestinal fluid, then drug release is accelerated, but the coating structure loses integrity
Solution Approach 1:
The soluble polymeric material in the outer layer is pre-positioned to dissolve rapidly upon contact with intestinal fluid, creating a fluid region that facilitates subsequent drug release. This preliminary action of the outer layer prepares the environment for accelerated drug delivery without requiring the entire coating structure to maintain integrity during release, as the pH dependent inner layer continues to provide structural support and controlled release functionality.
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 use of an isolation layer significantly reduces the lag time for drug release in the colon, achieving accelerated release compared to formulations without this layer, while also improving stability during storage, ensuring consistent drug delivery.
Implementation Method 1
the outer layer comprises a pH dependently soluble polymeric material which has a pH threshold at about pH 5 or above
Implementation Method 2
the inner layer comprises a soluble polymeric material which is soluble in intestinal fluid or gastrointestinal fluid
Data Source
AI summary
In a delayed release formulation comprising a core containing a drug and a delayed release coating for providing intestinal release, release of the drug in the colon is accelerated by including an isolation layer between the core and the delayed release coating. The delayed release coating comprises an inner layer and an outer layer. The outer layer comprises a pH dependently soluble polymeric material which has a pH threshold at about pH 5 or above. The inner layer comprises a soluble polymeric material which is soluble in intestinal fluid or gastrointestinal fluid, said soluble polymeric material being selected from the group consisting of a polycarboxylic acid polymer that is at least partially neutralised, and a non-ionic polymer, provided that, where said soluble polymeric material is a non-ionic polymer, said inner layer comprises at least one additive selected from a buffer agent and a base.