Uniform Microsphere Sustained Release Formulation
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Solution Overview
Problem
Biodegradable polymer microspheres with average volume-based particle diameters between 1 μm and 150 μm face challenges in controlled release due to non-uniform distribution of the main agent, leading to initial bursts or incomplete release, as the dispersion state of the main agent within the microsphere is often biased towards the surface or center, or contains empty holes, affecting the release profile.
Innovation Solution
A microsphere with a main agent uniformly dispersed in a polymer matrix, characterized by a variation coefficient of area ratios in four regions of 0.35 or less, ensuring even distribution and absence of empty holes, allowing controlled initial release and sustained release over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the main agent is incorporated in a biodegradable polymer matrix to achieve sustained release, then the release period is extended, but the main agent distribution becomes non-uniform causing initial burst or incomplete release
Solution Approach 1:
The patent applies parameter changes by controlling the molecular weight, composition ratio, and processing conditions of the biodegradable polymer matrix to achieve uniform main agent distribution. By adjusting these parameters, the patent resolves the contradiction between extended release period and distribution uniformity, preventing initial burst while maintaining sustained release capability.
2Speed
If the particle diameter is adjusted to control release rate, then the release profile is modified, but the main agent dispersion state remains unconfirmed and may be non-uniform
Solution Approach 1:
The patent introduces feedback mechanisms by implementing quality control measures that monitor and confirm the main agent dispersion state within the microsphere. Through systematic observation and analysis methods, the patent ensures that the desired dispersion state is achieved before finalizing the release rate control, thus resolving the contradiction between release rate adjustment and dispersion precision.
3Quantity of substance
If conventional microsphere formulations are used, then the initial burst is 10 to 30%, but this cannot be used with medicines requiring concentration control such as insulin and anticancer agents
Solution Approach 1:
The patent applies preliminary action by pre-optimizing the polymer matrix composition and main agent incorporation method before administration. Through preliminary control of the dispersion state and release characteristics, the patent eliminates the initial burst effect that would otherwise compromise concentration control reliability for sensitive medicines like insulin and anticancer agents.
4Stability of the object's composition
If the main agent is biased towards the surface or center of the microsphere, then the release profile becomes abnormal, but confirming the dispersion state requires complex observation methods
Solution Approach 1:
The patent replaces complex mechanical observation methods with simplified analytical approaches. By substituting intricate physical examination techniques with more straightforward analysis methods, the patent enables effective confirmation of main agent dispersion state without requiring overly complex observation systems, thus resolving the contradiction between release profile consistency and observation complexity.
Data Source
AI summary
The present application provides a microsphere in which a main agent is uniformly dispersed in a polymer matrix, wherein an average volume-based particle diameter of the microsphere is 1 μm or more and 150 μm or less, and a variation coefficient of area ratios in four regions is 0.35 or less, wherein the area ratios in four regions are calculated by (s/A)×100(%) wherein the four regions are prepared by preparing a cross section observation sample obtained by cutting the microsphere; observing the cross section observation sample with an electron microscope at a magnification capable of confirming the main agent in the microsphere or a higher magnification; and dividing the electron microscope observation image into four regions; and A is an area of a respective divided region, and s is a sum of cross section areas of the main agent included in the respective divided region. The microsphere of the present invention can appropriately control the initial release amount of the main agent and its release rate during a subsequent release period, and can continuously release the main agent for a predetermined period of time.