Supercritical Crystallization of Limus Macrolides for Bioavailability
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Solution Overview
Problem
The oral use of immunosuppressive macrolides from the 'limus' family, such as tacrolimus and sirolimus, is limited by their low and variable bioavailability due to their insolubility in biological media, and existing formulations face challenges with stability and conversion to a stable, crystalline form for pharmaceutical use.
Innovation Solution
A pharmaceutical composition comprising fine crystalline particles of immunosuppressive macrolides from the 'limus' family captured on pharmaceutically acceptable excipients, produced using a supercritical pressure fluid process that avoids solvents and surface modifiers, ensuring stability and improved bioavailability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If immunosuppressive macrolides are formulated in conventional forms, then manufacturing is simpler, but bioavailability is low and variable due to insolubility
Solution Approach 1:
The patent changes the physical state parameter of the macrolide from conventional forms to fine crystalline particles with specific size ranges (D10 < 5 μm, D50 < 2 μm, D90 < 10 μm). This parameter change in particle size and crystallinity improves solubility and bioavailability while maintaining manufacturing feasibility through controlled crystallization processes
Solution Approach 2:
The patent creates a composite formulation by combining fine crystalline macrolide particles with specific excipients including water-soluble polymers and cyclodextrins. This composite approach enhances the insoluble macrolide's bioavailability through improved dissolution characteristics without compromising manufacturing simplicity
2Reliability
If nanonization is used to improve solubility, then apparent solubility increases, but particles are unstable and tend to agglomerate
Solution Approach 1:
Instead of nanonization, the patent optimizes particle size parameters to a specific range (D50 between 0.5-5 μm) that balances solubility enhancement with physical stability. The fine crystalline form with controlled size distribution improves apparent solubility while avoiding the agglomeration problems associated with nanoscale particles
Solution Approach 2:
The patent introduces water-soluble polymers and cyclodextrins as intermediary substances that interact with the fine crystalline macrolide particles. These intermediaries prevent particle agglomeration and maintain dispersion stability, allowing the system to achieve both improved solubility and particle stability
3Reliability
If mechanical grinding is used to reduce particle size, then solubility improves, but crystallinity changes and amorphous form is produced which is less stable
Solution Approach 1:
The patent employs controlled crystallization parameters including temperature, solvent selection, and cooling rates to produce fine crystalline particles directly without mechanical grinding. This approach maintains the crystalline structure (preserving stability) while achieving the desired fine particle size (improving solubility) through phase transition control
Solution Approach 2:
The patent replaces mechanical grinding processes with chemical/physical crystallization methods. Instead of using mechanical force to reduce particle size, the invention uses controlled crystallization from solution to directly form fine crystalline particles, thereby maintaining crystallinity and long-term stability while achieving improved solubility
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 composition achieves enhanced bioavailability and stability of immunosuppressive macrolides, with improved dissolution rates and long-term chemical stability, addressing the limitations of existing formulations.
Implementation Method 1
a) a first step of extraction of the immunosuppressive macrolide from a source comprising the immunosuppressive macrolide, using a supercritical pressure fluid
Implementation Method 2
b) a second step of crystallisation of fine crystalline particles of the immunosuppressive macrolide from the solution obtained in step a)
Data Source
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AI summary
The invention relates to a Limus family immunosuppressive macrolide carrier/material formulation, as well as to an orally administered pharmaceutical composition containing same.