Spray Drying Solid Amorphous Dispersion Homogeneity
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Solution Overview
Problem
Current spray drying processes for forming pharmaceutical compositions of solid amorphous dispersions of low-solubility drugs and polymers face challenges in producing homogeneous, dense particles with low residual solvent content, as rapid evaporation leads to small, low-density particles, while slow evaporation can result in phase separation and high residual solvent levels.
Innovation Solution
A spray drying process involving a drying apparatus with controlled atomization and drying gas flow, where the spray solution is sprayed to form droplets less than 500 μm in size, with a drying gas flow rate and temperature managed to maintain the exhaust gas temperature below the solvent's boiling point, ensuring rapid solidification and low residual solvent levels, and recirculation of drying gas to optimize solvent evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rapid evaporation of solvent is used to form homogeneous solid amorphous dispersions, then homogeneity of drug dispersion is improved, but particle density decreases and particle size becomes very small
Solution Approach 1:
The invention changes the physical parameters of the drying process by controlling temperature, pressure, and gas flow rate to achieve rapid solvent removal. Specifically, maintaining drying gas temperature below the solvent boiling point and using high velocity gas flow enables homogeneous particle formation with acceptable density by optimizing the evaporation kinetics without causing excessive particle shrinkage or aggregation.
Solution Approach 2:
The invention employs dynamic control of drying conditions where the drying gas flow rate and temperature are adjusted during the process. The high velocity drying gas creates dynamic conditions that promote rapid solvent evaporation while the continuous adjustment of parameters prevents particle aggregation and maintains homogeneous drug dispersion throughout the particle matrix.
2Volume of stationary object
If slow evaporation of solvent is used to form larger, denser particles, then particle density is improved, but drug phase separation occurs and residual solvent levels increase
Solution Approach 1:
The invention applies the principle of rushing through the intermediate state by using rapid evaporation that quickly transitions the droplet from liquid to solid amorphous state. This rapid transformation skips the intermediate stage where phase separation could occur, directly forming homogeneous solid amorphous dispersions with acceptable density without allowing drug crystallization or phase separation.
Solution Approach 2:
The invention exploits phase transition principles by controlling the evaporation process to transition directly from liquid spray solution to solid amorphous dispersion. By maintaining drying gas temperature below solvent boiling point and using high velocity gas flow, the process achieves rapid solvent removal that prevents crystallization and phase separation, forming homogeneous amorphous particles with improved density.
3Volume of moving object
If slow evaporation of solvent is used to form larger particles, then particle size is improved, but residual solvent content increases leading to non-homogeneous dispersions and reduced productivity
Solution Approach 1:
The invention changes the drying parameters by using high velocity drying gas at controlled temperatures to achieve rapid solvent evaporation. This parameter optimization enables the formation of particles with acceptable size and density while minimizing residual solvent content, thereby improving both product quality and productivity by preventing particle adhesion to dryer surfaces.
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 process produces homogeneous, dense solid amorphous dispersions with higher drug-to-polymer ratios and low residual solvent content, enhancing drug concentration and bioavailability while maintaining efficient production scales.
Implementation Method 1
atomizing the spray solution to form droplets
Implementation Method 2
rapidly evaporating the solvent from the droplets to form the solid amorphous dispersion
Implementation Method 3
A drying gas is flowed through the inlet at a flow rate and a temperature TIN such that the droplets solidify in less than about 20 seconds
Data Source
AI summary
Spray drying processes are used to form pharmaceutical compositions comprising a solid amorphous dispersion of a drug and a polymer.