Drug Delivery System with Segmented Core and Shell
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Solution Overview
Problem
Current drug delivery systems for treating glaucoma and raised intraocular pressure face challenges in maintaining a constant and therapeutically effective drug concentration due to variable release kinetics and systemic side effects, particularly with topical administration methods.
Innovation Solution
A drug delivery system comprising a core and shell, where the core is made of a hydrolytically degradable polyesteramide copolymer with pendant ester and acid functionalities, and the shell is made of a hydrolytically degradable polymer that degrades via auto-accelerated kinetics, providing a controlled and prolonged release of the drug.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If topical administration of eye drops is used to treat glaucoma, then the drug can be easily administered to the eye, but the drug concentration becomes variable and intermittent due to overflow, tear washout, and patient compliance issues
Solution Approach 1:
The invention segments the drug delivery system into multiple components: a reservoir containing the drug, a rate-controlling membrane that regulates drug release, and a biocompatible housing. This segmentation allows the drug to be released in a controlled, steady manner rather than through variable topical administration, resolving the contradiction between ease of administration and concentration stability.
Solution Approach 2:
The rate-controlling membrane acts as an intermediary between the drug reservoir and the ocular environment. It mediates the drug release process by allowing controlled diffusion of the drug at a constant rate, eliminating the variability caused by tear washout and patient compliance issues while maintaining ease of administration through a single implantation procedure.
2Duration of action of stationary object
If polymer matrix systems are used for sustained drug release, then prolonged release can be achieved, but maintaining constant drug concentration within the therapeutic window becomes difficult due to non-linear release kinetics
Solution Approach 1:
The invention separates the drug storage function (reservoir) from the drug release control function (membrane). This segmentation allows the membrane to be specifically designed for linear, constant-rate release while the reservoir provides sustained drug supply, achieving both prolonged duration and constant concentration that polymer matrix systems cannot simultaneously provide.
Solution Approach 2:
The invention changes the release mechanism parameter from diffusion through a degrading polymer matrix (non-linear kinetics) to diffusion through a non-degrading rate-controlling membrane (linear kinetics). This parameter change enables constant drug concentration maintenance over an extended duration, resolving the contradiction between duration and concentration constancy.
3Productivity
If the shell degrades via auto-accelerated kinetics, then the drug release rate increases over time, but this may cause a burst release effect that exceeds therapeutic requirements
Solution Approach 1:
The invention segments the system into an inner reservoir and an outer shell with different degradation characteristics. The inner reservoir provides sustained drug supply while the outer shell with auto-accelerated degradation provides controlled release enhancement over time. This segmentation allows the beneficial productivity increase from auto-accelerated degradation while preventing harmful burst release through the reservoir-membrane architecture.
Solution Approach 2:
The invention applies different degradation qualities to different parts of the system: the rate-controlling membrane has non-degrading or slow-degrading properties for stable initial release, while the outer shell has auto-accelerated degradation for enhanced long-term release. This local quality differentiation resolves the contradiction between productivity and release profile control.
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 system achieves a prolonged and constant release of the drug, maintaining therapeutic levels for up to three months with minimal systemic side effects, effectively managing glaucoma and other conditions associated with raised intraocular pressure.
Implementation Method 1
the core is made of a hydrolytically degradable polyesteramide copolymer with pendant ester and acid functionalities
Implementation Method 2
the shell is made of a hydrolytically degradable polymer that degrades via auto-accelerated kinetics
Data Source
AI summary
The present invention relates to a drug delivery system comprising a core and a shell in which the core comprises a hydrolytically degradable polymer X which polymer backbone comprises pendant ester and acid functionalities and in which the shell comprises a hydrolytic degradable polymer Y. The hydrolytic degradable polymers X and Y are different polymers. Polymer X further comprises amino-acids in the polymer backbone and degrades via zero order degradation kinetics for a period of at least 3 months. Polymer Y degrades via auto-acceleration degradation kinetics.