Press Coated Tablet Erodible Barrier for Delayed Release
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Solution Overview
Problem
Existing delayed release tablets often fail to release active pharmaceutical ingredients effectively in areas of the GI tract with poor motility, viscous or solid luminal contents, or limited water availability, due to rupture mechanisms that may not fully open or trigger release after passing the intended delivery site.
Innovation Solution
A press-coated tablet with a delayed release layer comprising a wax and a combination of two or more grades of low-substituted hydroxypropyl cellulose (L-HPC) provides a controlled erosion mechanism for sustained release of active ingredients over several hours, independent of the core formulation or location in the GI tract.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rupture mechanism is used for delayed release, then the tablet can be designed to open after swelling, but the release may be physically impeded in areas of the GI tract with poor motility, viscous or solid luminal contents, or faecal compaction
Solution Approach 1:
The patent replaces the mechanical rupture mechanism with a chemical erosion mechanism. The barrier layer is designed to gradually erode through chemical interaction with GI fluids, transforming the release mechanism from a mechanical swelling-burst system to a chemical dissolution system that is less dependent on mechanical forces and more adaptable to various GI conditions.
Solution Approach 2:
The patent changes the fundamental parameter of the release mechanism from mechanical (swelling and rupturing) to chemical (erosion and dissolution). By formulating the barrier layer with specific materials and ratios, the system achieves controlled chemical erosion that provides reliable delayed release while adapting to different GI tract environments without requiring mechanical opening.
2Reliability
If a polymer membrane based release barrier is used, then controlled release can be achieved, but the construction becomes complex and expensive and commonly utilise solvents for processing
Solution Approach 1:
The patent employs a simple, inexpensive barrier layer formulation using common pharmaceutical excipients (wax and disintegrant) that can be easily processed without complex equipment or solvent systems. This straightforward construction replaces complex polymer membrane technologies with a simpler, more economical approach that achieves controlled release through basic erosion mechanisms.
Solution Approach 2:
The patent extracts and eliminates the complex polymer membrane component from the barrier construction, retaining only the essential functional elements (wax and disintegrant) needed for controlled erosion. This simplification removes the need for complex processing solvents and manufacturing equipment while maintaining the core controlled release function.
3Ease of manufacture
If a single grade of L-HPC is used in the barrier layer, then the formulation is simple, but the control over the release delay period is limited
Solution Approach 1:
The patent segments the L-HPC component into multiple grades with different erosion rates and functional characteristics. By combining at least two different grades of L-HPC in the barrier layer, the system achieves more precise control over the release delay period, as each grade contributes differently to the overall erosion profile and drug release timing.
Solution Approach 2:
The patent creates a composite barrier layer formulation that combines multiple grades of L-HPC with different properties (erosion rates, binding characteristics) to achieve optimized controlled release. This composite approach allows fine-tuning of the release profile by adjusting the ratio and selection of different L-HPC grades, providing superior control over the delay period while maintaining formulation feasibility.
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
This approach offers a wider range of control over the delay period and ensures steady, reproducible release, overcoming the limitations of traditional swell and rupture mechanisms, and can be used for timed dosing regimens such as night-time dosing or treatment of conditions like insomnia or morning stiffness.
Implementation Method 1
L-HPC is not soluble in water and instead absorbs water, thereby expanding in volume
Implementation Method 2
the disintegrant swelling on exposure to liquid and causing a surface weakening in the release barrier
Implementation Method 3
the barrier starts to erode at the tablet surface, and gradually continues until all of the barrier layer is removed
Data Source
AI summary
A press coated tablet for delayed release of an active ingredient comprising: (a) a core comprising one or more active ingredients, and; (b) an erodible delayed release barrier surrounding the core and comprising a wax and two or more grades of L-HPC, wherein the wax and L-HPC are provided in a weight ratio of wax to L-HPC of from 30%:70% to 70%:30%. The invention also relates to a method of making the press coated tablet.