Pharmaceutical Particle Drying via Glass Transition Modulation
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Solution Overview
Problem
Conventional secondary drying processes for pharmaceutical compositions are slow and energy-inefficient, requiring long times to reduce residual solvent content to acceptable levels, especially as the glass transition temperature of particles increases during solvent removal, hindering mass transfer and evaporation rates.
Innovation Solution
Exposing pharmaceutical particles to a volatile mobility-enhancing agent, such as water or ethanol, reduces the glass transition temperature, enhancing solvent diffusion and mass transfer rates, allowing for quicker and more efficient removal of residual solvent through controlled drying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional secondary drying processes are used to remove residual solvent from pharmaceutical particles, then the residual solvent content is reduced to acceptable levels, but the drying time becomes excessively long and energy consumption increases
Solution Approach 1:
The invention changes the physical-chemical parameters of the drying system by introducing a volatile mobility-enhancing agent that temporarily reduces the glass transition temperature of the particles. This parameter change maintains the particles in a more mobile state during drying, significantly accelerating solvent removal rates while keeping the process energy-efficient and time-effective
2Reliability
If conventional secondary drying processes are used to remove residual solvent from pharmaceutical particles, then the residual solvent content is reduced to acceptable levels, but energy consumption increases
Solution Approach 1:
By temporarily modifying the glass transition temperature through the volatile mobility-enhancing agent, the invention enables solvent removal at lower energy inputs. The particles remain in a more mobile state that facilitates solvent diffusion and evaporation without requiring excessive thermal energy, thus reducing overall energy consumption while achieving the same residual solvent content
3Stability of the object's composition
If the glass transition temperature of particles increases during solvent removal, then the particles become more stable, but mass transfer and evaporation rates decrease
Solution Approach 1:
The invention dynamically adjusts the glass transition temperature during the drying process by introducing a volatile mobility-enhancing agent. This creates a time-dependent system where the Tg is temporarily reduced to enhance mass transfer and evaporation rates, allowing the process to proceed rapidly while maintaining final particle stability once the agent evaporates
Solution Approach 2:
The volatile mobility-enhancing agent induces a temporary parameter change in the glass transition temperature, creating a window of enhanced molecular mobility that accelerates solvent removal. This dynamic parameter adjustment resolves the contradiction between stability and productivity by allowing rapid drying when needed while preserving final product stability
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 process significantly reduces the time required to achieve low residual solvent levels, improving the efficiency of solvent removal and maintaining high mass-transfer rates throughout the drying process.
Implementation Method 1
exposing the particles in a chamber to a volatile mobility-enhancing agent that is different from the solvent, so that the glass-transition temperature of the particles is reduced
Implementation Method 2
removing the stripping gas from the chamber along with at least a portion of the solvent
Implementation Method 3
enhancing solvent diffusion and mass transfer rates
Data Source
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AI summary
A secondary drying process is disclosed for removing residual solvent from drug-containing particles that have been formed by solvent-based processes.