Amorphous Drug Crystallization via Surfactant Mediation
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Solution Overview
Problem
Current methods for converting amorphous forms of drugs, such as everolimus, into crystalline forms for medical devices are limited in terms of efficiency and stability, particularly in forming microcrystals with desirable morphology and size for effective drug delivery.
Innovation Solution
A method involving the combination of a nucleation initiator, a surfactant solution, and an amorphous form of a drug in a solvent mixture like ethyl acetate and heptane, followed by incubation to form crystalline microcrystals, with optional steps of filtering, washing, and drying to produce shelf-stable microcrystals free of surfactants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used to convert amorphous drugs to crystalline forms, then the process is simpler, but the efficiency and stability of forming microcrystals with desirable morphology and size are limited
Solution Approach 1:
A surfactant is introduced as an intermediary substance to mediate the crystallization process. The surfactant interacts with both the amorphous drug particles and the solvent, facilitating the formation of microcrystals with controlled morphology and size. This intermediary enables efficient crystallization while maintaining processability, resolving the contradiction between productivity and complexity.
Solution Approach 2:
The method employs systematic changes in crystallization parameters including temperature, solvent composition, surfactant concentration, and incubation time to optimize microcrystal formation. By carefully controlling these parameters, the process achieves high efficiency and stability in producing microcrystals with desirable properties, overcoming the limitations of conventional approaches.
2Reliability
If amorphous form of drug is used, then the drug can be easily processed, but the stability and suspension properties are insufficient for effective drug delivery
Solution Approach 1:
The method utilizes controlled phase transition from amorphous to crystalline state to improve drug stability. By inducing crystallization through surfactant-mediated processes, the drug transforms from the less stable amorphous form to the more stable crystalline microform, enhancing reliability while maintaining manufacturability through controlled processing conditions.
Solution Approach 2:
The crystallization process produces segmented microcrystals with specific size ranges rather than large crystalline structures. This segmentation into micro-scale particles maintains ease of processing and suspension properties while significantly improving stability and drug delivery effectiveness compared to the amorphous form.
3Reliability
If microcrystals with specific dimensions are formed, then the coating stability and application performance are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The surfactant-mediated crystallization process enables self-organization of drug molecules into microcrystals with consistent dimensions. The surfactant creates a controlled microenvironment that guides crystal growth, allowing the system to self-regulate and produce uniform microcrystals without requiring extremely precise external control, thus improving coating stability while managing manufacturing precision requirements.
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 effectively converts amorphous everolimus into crystalline microcrystals with specific dimensions, enhancing stability and suspension properties, making them suitable for drug-coated medical devices with improved coating stability and application.
Implementation Method 1
combining a nucleation initiator, a surfactant solution, and an amorphous form of a drug to form a drug precursor dispersion/suspension; and incubating the drug precursor dispersion/suspension to allow the drug to convert from the amorphous form to a crystalline form
Implementation Method 2
combining a nucleation initiator, a surfactant solution, and an amorphous form of a drug to form a drug precursor dispersion/suspension
Data Source
AI summary
Methods are disclosed including methods for crystallizing a material such as a drug. An example method may include combining a nucleation initiator, a surfactant solution, and an amorphous form of a drug to form a drug precursor dispersion/suspension. The method may also include incubating the drug precursor dispersion/suspension to allow the drug to convert from the amorphous form to a crystalline form.