Low Temperature Drying for Drug-Polymer Compositions
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Solution Overview
Problem
Existing methods for removing solvents from drug-containing polymeric compositions used in implantable medical devices often result in solvent residue or degradation of therapeutic drugs, particularly at high temperatures, which compromises the efficacy and safety of the devices.
Innovation Solution
A method involving low-temperature drying processes, such as lyophilization, supercritical fluid extraction, and azeotropic extraction, is employed to reduce solvent content in drug-containing polymeric compositions to less than 10,000 ppm without degrading the therapeutic agents, using temperatures below 60°C and pressures suitable for preserving drug potency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature drying is used to remove solvent, then solvent removal efficiency is improved, but therapeutic drug degradation occurs
Solution Approach 1:
The patent changes the temperature parameter from high temperature (60-110°C) to low temperature (below 60°C, preferably 25-45°C) drying conditions. This parameter change enables effective solvent removal while preventing thermal degradation of the thermally unstable amorphous therapeutic drugs, thus resolving the contradiction between solvent removal efficiency and drug stability
Solution Approach 2:
The patent employs a composite drying approach that combines conventional drying methods with low temperature drying methods. This composite approach achieves both efficient solvent removal and drug preservation by utilizing the complementary strengths of different drying techniques while avoiding the weaknesses of each individual method
2Reliability
If ambient temperature drying is used, then drug content is preserved, but solvent removal efficiency is insufficient
Solution Approach 1:
The patent optimizes the temperature parameter by using low temperature (below 60°C, preferably 25-45°C) rather than ambient temperature, combined with controlled humidity and air flow conditions. This parameter optimization achieves both drug content preservation and significantly improved solvent removal efficiency compared to ambient drying
3Reliability
If low temperature drying is used, then drug stability is maintained, but solvent residue remains higher than desired
Solution Approach 1:
The patent uses a composite drying system that combines conventional drying methods with low temperature drying methods. This composite approach achieves both drug stability maintenance and reduced solvent residue by utilizing the complementary strengths of different drying techniques, where conventional drying provides initial solvent removal and low temperature drying provides final solvent reduction while preserving drug integrity
Solution Approach 2:
The patent implements a continuous multi-stage drying process that progressively removes solvent at optimized temperature conditions. This continuous action ensures thorough solvent removal while maintaining drug stability through controlled, sequential drying stages rather than single-step processing
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 approach effectively minimizes solvent residue while maintaining the integrity and potency of therapeutic agents, enhancing the safety and efficacy of drug delivery from implantable medical devices by ensuring controlled and sustained drug release.
Implementation Method 1
the solvent(s) contained in the polymeric film can be gradually removed by evaporation under ambient conditions
Implementation Method 2
treating the drug-containing polymeric composition using a low-temperature drying process at a processing temperature of less than 60° C.
Implementation Method 3
A method involving low-temperature drying processes, such as lyophilization
Implementation Method 4
A method involving low-temperature drying processes, such as lyophilization, supercritical fluid extraction
Implementation Method 5
A method involving low-temperature drying processes, such as lyophilization, supercritical fluid extraction, and azeotropic extraction
Data Source
AI summary
The present invention relates to a process for reducing solvent contents in drug-containing polymeric compositions. Specifically, the solvent contents in the drug-containing polymeric compositions are first reduced by one or more conventional drying methods, to a range from about 0.5 wt % to about 10 wt % of the total weight of the polymeric composition. Subsequently, the drug-containing polymeric compositions are further treated by one or more low temperature (i.e., having processing temperatures of less than 60° C.) drying methods for further reduction of the solvent content to less than 10,000 ppm.