Solid Microneedle Drug Release via Solvent Casting
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Solution Overview
Problem
Current methods for manufacturing solid microneedles, such as lithography or hot embossing, are expensive and lack stability, and existing processes for molding water-insoluble polymers like PLA are not sufficiently developed, posing safety and quality issues, as well as complexity in drug delivery and potential structural separation risks.
Innovation Solution
A solvent casting method using a water-insoluble polymer like PLA and specific sugars to create microneedles, where the sugar is added in powder form to the polymer solution, allowing for controlled drug release through varying sugar concentrations and forms to achieve rapid or sustained release profiles, and using DMSO as a solvent to enhance safety and reduce bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lithography or hot embossing is used to manufacture solid microneedles, then manufacturing precision and structural integrity are improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent changes the physical state parameters of the polymer material by controlling solvent evaporation to transition from liquid solution to solid microneedle structure. This parameter-based approach replaces complex mechanical lithography processes with a simpler solvent casting method that achieves comparable structural integrity through controlled phase transition rather than mechanical force.
Solution Approach 2:
The patent replaces mechanical manufacturing systems (lithography, hot embossing) with a chemical/solvent-based system. Instead of using mechanical pressure and heat to form microneedles, the invention uses solvent evaporation and polymer crystallization to self-form the microneedle structure, eliminating the need for complex mechanical manufacturing equipment.
2Strength
If water-insoluble polymers like PLA are molded using conventional methods, then structural strength is improved, but manufacturing feasibility and safety decrease due to insufficient process development
Solution Approach 1:
The patent introduces an organic solvent as an intermediary material that enables the processing of water-insoluble polymers. The solvent acts as a temporary medium that dissolves the polymer, allows for microneedle formation through casting, and then evaporates completely, leaving behind the solid microneedle structure. This intermediary approach makes manufacturing water-insoluble polymer microneedles feasible without requiring advanced molding processes.
Solution Approach 2:
The patent performs preliminary dissolution of the water-insoluble polymer in an organic solvent before casting. This preliminary action transforms the insoluble polymer into a workable solution state, enabling subsequent casting and shaping operations. After the microneedle structure is formed and the solvent evaporates, the final product retains the desired strength while the manufacturing process remains simple and feasible.
3Duration of action of moving object
If sugars are added to polymer solution to control drug release, then drug delivery control is improved, but solution homogeneity and processing difficulty worsen
Solution Approach 1:
The patent applies local quality by incorporating sugars at specific locations and concentrations within the microneedle structure to create zones with different drug release characteristics. By strategically placing sugar components in specific regions of the polymer matrix, the invention achieves controlled drug release profiles while maintaining overall solution processability through localized rather than uniform modification.
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 enables the cost-effective production of microneedles with varied physical properties, ensuring stability and safety, allowing for efficient drug delivery with controlled release rates, suitable for both cosmetic and pharmaceutical applications, and is scalable with minimal risk of structural separation.
Implementation Method 1
drying and separating the microneedle from the mold
Data Source
AI summary
The present disclosure relates to a solid microneedle structure prepared using a water-insoluble polymer and a technique for manufacturing the same, wherein the technique can control the drug release rate of the microneedle: a rapid-release type or a sustained release type, the drug included in the microneedle may be various cosmetic or pharmaceutical active ingredients, and the microneedle can have an appropriate release rate suitable for the drug by the method of the invention.