Porous Matrix Sterilization of Microparticles
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Solution Overview
Problem
Current sterilization methods for polymer-based microparticles, such as gamma irradiation and ethylene oxide gas sterilization, can cause degradation and are costly, while heat-based methods are not suitable due to polymer susceptibility, leading to challenges in ensuring the stability and effectiveness of pharmaceutical and cosmetic applications.
Innovation Solution
A porous solid matrix is created by dispersing microparticles in an aqueous solution with a viscosity-inducing polymer and stabilizer, followed by lyophilization, allowing for efficient gas sterilization at lower temperatures, ensuring complete exposure to sterilizing gases like ethylene oxide, thereby maintaining particle stability and integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gamma irradiation is used to sterilize microparticles, then sterilization is achieved, but polymer degradation occurs and molecular weight reduces
Solution Approach 1:
The patent embeds microparticles within a porous matrix of biodegradable polymer and hydrophilic polymer that acts as a protective intermediary. This matrix structure allows sterilizing agents to penetrate and kill microorganisms while the hydrophilic polymer component protects the microparticle-forming polymer from direct contact and degradation, thus maintaining molecular weight and composition stability during sterilization
Solution Approach 2:
The patent changes the physical and chemical parameters of the sterilization process by conducting sterilization at lower temperatures (e.g., 37°C or room temperature) and using alternative sterilizing agents such as ethylene oxide gas or peracetic acid instead of high-energy gamma irradiation. These parameter changes reduce the harshness of sterilization, preventing polymer degradation while still achieving effective sterilization
2Reliability
If ethylene oxide gas sterilization is used, then sterilization is achieved, but the process is costly and complex
Solution Approach 1:
The patent employs a disposable sterile barrier packaging system that can be sterilized using simple, inexpensive methods such as autoclaving or chemical sterilization. This eliminates the need for complex and expensive sterilization equipment, as the packaging itself provides the sterile barrier, allowing the use of cost-effective sterilization processes
Solution Approach 2:
The porous matrix structure serves multiple functions simultaneously: it provides mechanical support for microparticles, enables controlled release, facilitates sterilization by allowing penetratio of sterilizing agents, and maintains stability during storage. This multi-functionality simplifies the overall sterilization process by eliminating the need for separate stabilization and sterilization steps
3Reliability
If heat sterilization is used, then sterilization is achieved, but polymer deformation and degradation occur
Solution Approach 1:
The patent fundamentally changes the temperature parameter of sterilization from high heat (121°C or higher) to low temperature (37°C or room temperature). This parameter change makes the sterilization process compatible with heat-sensitive polymeric materials, preventing thermal degradation, deformation, and molecular weight reduction while still achieving effective sterilization through extended exposure time or use of chemical sterilants
Solution Approach 2:
The hydrophilic polymer matrix acts as a thermal intermediary that protects the microparticle-forming polymer from direct thermal stress. The matrix structure allows heat to be applied more gradually and uniformly, reducing thermal gradients and hot spots that could cause polymer deformation, while the hydrophilic polymer's thermal properties buffer against excessive temperature exposure
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 method allows for reproducible and effective sterilization of microparticles at room temperature or below 50°C, preventing degradation and ensuring the stability of the particles during and after sterilization, while also facilitating easy reconstitution into a uniform suspension, thus improving the stability and efficacy of pharmaceutical and cosmetic applications.
Implementation Method 1
The matrix allows easy penetration of the gas, such as EtO. Therefore, all microparticles are readily exposed to the sterilizing effect of the gas.
Implementation Method 2
lyophilizing the resultant dispersion of step a) to produce a porous polymer matrix upon drying
Data Source
AI summary
Methods of sterilizing microparticles using a porous solid matrix which allows penetration of a sterilizing gas such as EtO to pass through are disclosed. The methods also include preparing a suspension of the sterilized microparticles by reconstituting the porous matrix containing the microparticles.