Core-Shell Microspheres for Tunable Drug Release
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a challenge in accurately controlling the rate of release of substances from encapsulated particles, particularly in introducing a delay period for release to ensure effective delivery at the desired location, which is crucial for sequential delivery of multiple substances or cyclic delivery of hormones.
Innovation Solution
The development of core-shell microspheres comprising a core of poly(D,L-lactic-co-glycolic acid) (PLGA) and a shell of poly(L-lactic acid) (PLLA), where the first polymer forms continuous pathways through the shell, allowing for controlled release by degrading at different rates, enabling tunable delayed release profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single polymer matrix is used for substance release, then the release mechanism is simple, but the ability to control release rate and introduce delay period is limited
Solution Approach 1:
The particle is segmented into distinct functional zones: a core region containing the substance to be released, and a shell region comprising a polymer matrix. This segmentation allows different regions to perform different functions - the core holds the substance while the shell controls the release rate through its polymer composition and degradation characteristics.
Solution Approach 2:
Different polymer materials are used in different regions of the particle to create local quality variations. The shell region uses a polymer matrix with specific degradation properties that differ from the core region, enabling localized control over substance release characteristics in the shell while maintaining substance containment in the core.
2Loss of time
If the polymer degrades rapidly, then the substance is released quickly, but a delay period cannot be achieved
Solution Approach 1:
The degradation rate of the polymer matrix is controlled by changing its molecular weight and composition parameters. By selecting polymers with higher molecular weights and appropriate chemical compositions, the degradation rate is reduced to enable a delay period before substance release begins, while still allowing for controlled release over the desired duration.
3Duration of action of stationary object
If the polymer molecular weight is low, then the degradation and release are fast, but sustained release is difficult to achieve
Solution Approach 1:
The molecular weight of the polymer matrix is increased to slow down degradation and enable sustained release over extended periods. Additionally, the polymer composition is optimized to balance degradation rate with release duration, allowing the substance to be released gradually over weeks or months rather than days.
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 allows for precise control over the release lag time and rate of therapeutic substances, enabling long-term sustained release and sequential delivery of multiple substances, enhancing the effectiveness of treatments such as pain relief and glaucoma management.
Implementation Method 1
a shell surrounding said core and comprising the first polymer and a second polymer, said second polymer being less rapidly degradable than the first polymer
Data Source
AI summary
The specification describes a substance comprising a plurality of microparticles. The microparticles comprise a core comprising a first polymer and a shell surrounding said core and comprising the first polymer and a second polymer, wherein the second polymer is less rapidly degradable than the first polymer. A process for making the microparticles and uses of the microparticles are also described.