Injectable PLA Microspheres With Uniform Size and Water Dispersibility
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Solution Overview
Problem
PLA microspheres in medical applications suffer from agglomeration, poor dispersibility in water, and inconsistent degradation rates, leading to challenges in injection and controlled drug release.
Innovation Solution
A preparation method involving spray drying of a solution comprising an oil phase with PLA, an organic solvent, and an aqueous phase with surfactants and macromolecular substances, followed by homogeneous emulsification and controlled drying conditions, results in uniform, injectable PLA microspheres with stable degradation rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional PLA microsphere preparation methods are used, then the microspheres can be formed, but they suffer from agglomeration and poor dispersibility in water, making them difficult to inject
Solution Approach 1:
The patent introduces surfactants as intermediary substances that mediate between the hydrophobic PLA microspheres and the aqueous environment. The surfactants adsorb onto the microsphere surfaces, providing hydrophilic groups that improve water dispersibility while maintaining microsphere integrity and injectability.
Solution Approach 2:
The patent modifies surface parameters of the PLA microspheres by controlling emulsification conditions, drying parameters, and surfactant concentrations. These parameter changes alter the surface properties to reduce agglomeration tendency and improve dispersibility without compromising the microspheric structure needed for injection.
2Manufacturing precision
If single PLA microspheres are used, then they can be prepared simply, but the degradation rate is slow in early stage and accelerates in later stage, which is not conducive to control of drug dosage
Solution Approach 1:
The patent creates composite microsphere systems by combining PLA with other materials during emulsification. This composite structure modifies the degradation profile to achieve more uniform drug release rates, preventing the burst release effect while maintaining manufacturing feasibility through integrated preparation processes.
Solution Approach 2:
The patent applies different materials or coatings to specific regions or surfaces of the microspheres to create localized properties that control degradation. This allows different parts of the microsphere system to degrade at different rates, achieving overall uniform drug release while keeping the bulk preparation process relatively simple.
3Manufacturing precision
If homogeneous emulsification is performed at high rotational speed for extended time, then uniform microspheres are obtained, but production efficiency is reduced
Solution Approach 1:
The patent performs preliminary emulsification at high speed to establish uniform droplet distribution, then maintains uniformity with lower speed agitation. This preliminary high-energy action creates the initial uniform structure that prevents aggregation during subsequent processing, reducing total processing time while maintaining microsphere uniformity.
Solution Approach 2:
The patent uses periodic or pulsed emulsification cycles with alternating high and low speed phases. The high-speed pulses create uniform droplets periodically, while lower-speed intervals allow controlled coalescence and reduce energy consumption, achieving uniform microspheres with improved overall production efficiency.
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 method produces microspheres with controlled particle sizes, good biocompatibility, and consistent degradation rates, enabling effective drug delivery and mass production, overcoming issues of agglomeration and inconsistent release.
Implementation Method 1
performing homogeneous emulsification on the spray solution to obtain an emulsified spray solution
Implementation Method 2
drying the emulsified spray solution to obtain the injectable PLA microspheres
Data Source
Figure 1
AI summary
A preparation method and an application of injectable polylactic acid (PLA) microspheres are provided, which relate to the field of biomedical technologies. The preparation method of the injectable PLA microspheres include: S01, preparing a spray solution; S02, performing homogeneous emulsification on the spray solution to obtain an emulsified spray solution; and S03, drying the emulsified spray solution. The spray solution includes an oil phase and an aqueous phase, and a weight ratio of the oil phase and the aqueous phase is 1-10 : 1-10. The oil phase includes PLA and an organic solvent, and the aqueous phase includes a surfactant, macromolecular substances and deionized water. A particle size of the injectable PLA microspheres is basically below 60 µm, and the injectable PLA microspheres have a complete form, are independent of each other, do not exhibit agglomeration and have good biocompatibility, which can satisfy the requirement of the injection.