Biodegradable Polymer Microspheres With Cellulose for Sustained Injection
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Solution Overview
Problem
Ethyl cellulose, a safe binder for oral drug formulations, is not suitable for parenteral use, and biodegradable polymers used in parenteral formulations lack the stability and controlled release properties needed for effective drug delivery.
Innovation Solution
A novel microsphere composition combining biodegradable polymers like poly(D,L-lactide-co-glycolide) with ethyl cellulose, formulated to include specific ratios of biodegradable polymer, cellulose-derived material, and therapeutic agents, providing a controlled release mechanism for parenteral administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ethyl cellulose is used in oral drug formulation, then physical integrity and humidity resistance are improved, but it cannot be used in parenteral drug formulation
Solution Approach 1:
The patent combines ethyl cellulose (a non-biodegradable cellulose ether) with biodegradable polymers (PLA, PLGA, or polyanhydrides) to create a composite microsphere system. This composite approach allows the formulation to benefit from ethyl cellulose's physical integrity and humidity resistance while the biodegradable polymer component enables parenteral use through controlled degradation in the body. The synergistic combination resolves the contradiction between stability and adaptability.
2Adaptability or versatility
If biodegradable polymers are used in parenteral formulations, then parenteral compatibility is achieved, but stability and controlled release properties are insufficient
Solution Approach 1:
The patent creates a composite system where biodegradable polymers (providing parenteral compatibility and degradation capability) are combined with ethyl cellulose (providing enhanced stability and controlled release properties). The ethyl cellulose component forms a matrix that modulates drug release kinetics, while the biodegradable polymer ensures compatibility with parenteral administration and ultimate degradation in the body.
3Stability of the object's composition
If ethyl cellulose is combined with biodegradable polymers, then controlled release and stability are improved, but formulation complexity increases
Solution Approach 1:
The patent merges two polymer systems (ethyl cellulose and biodegradable polymers) into a single integrated microsphere formulation. By combining these materials during the microsphere fabrication process, the formulation achieves controlled release and stability benefits while maintaining a unified structure rather than requiring separate delivery systems. The merging of materials into a composite matrix simplifies the overall formulation architecture.
4Strength
If high molecular weight biodegradable polymer is used, then mechanical strength is improved, but degradation rate decreases
Solution Approach 1:
The patent utilizes parameter changes by selecting biodegradable polymers with molecular weights greater than 10,000 Daltons, which provides adequate mechanical strength for microsphere integrity. The controlled release properties are achieved through the specific composition ratio of ethyl cellulose to biodegradable polymer, where the ethyl cellulose content (0.1% to 5% viscosity fraction) modulates the degradation rate and drug release kinetics, balancing strength and degradation requirements.
Data Source
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AI summary
Novel microsphere compositions for use in parenteral formulations are provided. The microspheres comprise a biodegradable polymer of a molecular weight greater than 10,000 daltons, an active therapeutic agent, and a cellulose-derived material such as ethyl cellulose, carboxymethyl cellulose, hydroxypropylmethyl cellulose, or sodium carboxymethyl cellulose. The microsphere compositions decreased deviation in mean microsphere diameter, improved drug entrapment, and improved microsphere stability.