Atmospheric Spray Freeze Drying for Biologically Active Powders
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Solution Overview
Problem
Current methods for drying pharmacologically active compositions, such as proteins and vaccines, are costly and inefficient, leading to protein degradation and short shelf lives due to heat sensitivity and the need for cryoprotectants, with lyophilization being slow and expensive and spray drying causing structural degradation.
Innovation Solution
The method involves spraying a carrier liquid containing a powder-forming ingredient into a chamber, freezing the droplets, and drying them using a controlled gas flow at atmospheric pressure, with a low initial gas flow to prevent accumulation and a higher flow for efficient drying, maintaining biological activity and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lyophilization is used to dry heat-sensitive materials, then biological activity is preserved, but the process is slow and expensive
Solution Approach 1:
The invention changes the operating pressure parameter from vacuum (lyophilization) to atmospheric pressure, and changes the temperature parameter from very low (lyophilization) to controlled elevated temperatures. This allows rapid drying while maintaining biological activity through the unique combination of atmospheric pressure operation and controlled temperature profiling that prevents protein degradation
Solution Approach 2:
The invention utilizes controlled phase transitions of water (liquid to vapor) at atmospheric pressure through controlled heating, rather than sublimation under vacuum. The process controls the phase transition rate to achieve rapid drying while preventing protein denaturation through appropriate temperature management
2Productivity
If spray drying is used to dry materials, then drying speed is improved, but protein structural degradation occurs due to heat
Solution Approach 1:
The invention dynamically adjusts the gas flow rate and temperature throughout the drying process. The gas flow rate increases from initial low flow to higher flow rates as drying progresses, and temperature is dynamically controlled to prevent protein degradation while maintaining rapid drying. This dynamic control allows the process to achieve both high productivity and protein structural integrity
Solution Approach 2:
The invention implements feedback control by monitoring the drying process and adjusting gas flow rate and temperature accordingly. The system responds to drying progress and material state to optimize both drying speed and protein preservation, preventing structural degradation while maintaining high productivity
3Ease of manufacture
If conventional drying methods are used, then equipment cost is reduced, but additional processing steps are required
Solution Approach 1:
The invention merges multiple processing steps (drying, powder formation, and flowability enhancement) into a single atmospheric spray drying operation. The process produces free-flowing powders directly without requiring separate grinding, milling, or sieving steps, thereby simplifying the overall manufacturing process while using relatively simple equipment
4Productivity
If high gas flow rate is used during spraying, then drying efficiency is improved, but frozen particles accumulate
Solution Approach 1:
The invention dynamically adjusts the gas flow rate during the drying process. Initially, a lower gas flow rate is used to prevent accumulation of frozen particles and ensure proper particle distribution. As drying progresses and particles become more stable, the gas flow rate is increased to enhance drying efficiency. This dynamic adjustment resolves the contradiction between drying efficiency and particle distribution 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
This approach effectively maintains biological activity of dried powders for long durations at a lower economic cost, avoiding the drawbacks of existing methods by ensuring efficient drying and minimizing protein degradation.
Implementation Method 1
freezing the liquid droplets into frozen particles
Implementation Method 2
drying them using a controlled gas flow at atmospheric pressure
Data Source
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AI summary
Methods of preparing dried powders of biologically active compositions are disclosed. They are designed to provide dried material that maintains biological activity at low economic cost. Compositions made by the above methods are also described.