Multi-Chamber Microwave Vacuum Drying for Sterile cGMP Production

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Microwave vacuum-drying of pharmaceutical biologic materials at a large scale is difficult to comply with current Good Manufacturing Practice (cGMP) regulations due to issues with particle generation, controlled drying, and chamber cleaning and sterilization.

Innovation Solution

A microwave vacuum dryer with a multi-chamber design, including a loading, drying, and unloading chamber, equipped with vacuum pumps, magnetrons, and gaskets for sterilization, allows for controlled and reproducible drying while meeting cGMP standards, using a semi-continuous or batch mode operation with tray transport systems and inert gas backfilling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If microwave vacuum-drying is used for large-scale pharmaceutical biologic materials, then drying speed and product quality are improved, but compliance with cGMP regulations becomes difficult due to particle generation and sterilization issues

Engineering Contradiction:
Improvedrying speedVSAvoidcGMP compliance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The drying chamber is divided into multiple zones with separate doors (first door for loading, second door for drying chamber access, third door for unloading). Each chamber (loading, drying, unloading) can be independently sealed and sterilized, allowing the drying process to continue while other chambers are being cleaned or sterilized, thus maintaining cGMP compliance without sacrificing productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Double gaskets are installed at each door interface: an outer gasket that provides the primary seal and an inner gasket that provides a secondary seal. This intermediary sealing system ensures reliable containment of the vacuum environment and prevents particle contamination, meeting cGMP requirements while maintaining efficient drying operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If single gasket sealing is used in microwave vacuum dryer, then device complexity is reduced, but sterile boundary protection and vacuum sealing reliability are insufficient for cGMP environments

Engineering Contradiction:
Improvegasket configurationVSAvoidsterile boundary protection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The sealing system is segmented into two distinct gaskets: an outer gasket for primary sealing and an inner gasket for secondary sealing and sterile boundary protection. This segmentation provides redundant protection against contamination while maintaining vacuum integrity, essential for cGMP compliance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The double gasket system provides a backup sealing mechanism that compensates for potential failures or leaks in the primary seal. This prior cushioning ensures that sterile boundaries are maintained even if one gasket fails, preventing particle generation and contamination during the drying process.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If multi-chamber design with multiple doors is implemented, then cGMP compliance through controlled sterilization is achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvesterilization controlVSAvoidchamber configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The dryer is divided into functionally independent chambers (loading chamber, drying chamber, unloading chamber) that can be separately sterilized and maintained under different conditions. This segmentation allows each chamber to be optimized for its specific function while meeting cGMP sterilization requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

While one chamber is being sterilized or cleaned, the drying chamber can continue its operation, and other chambers can be prepared for the next cycle. This continuous operation maintains productivity despite the increased complexity of multiple chambers and sterilization procedures.

Inventive Principle:
Principle #20Continuity of useful action

4Object-generated harmful factors

If automatic door operation is used for second and third doors, then particle generation is minimized during transfer, but control system complexity increases

Engineering Contradiction:
Improveparticle generationVSAvoidcontrol system
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

Automatic door operation systems act as intermediaries that precisely control the opening and closing sequences of the second and third doors. This automated control minimizes the time chambers are open to the environment, reducing particle generation during transfers, while the control system manages the added complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables efficient, continuous or semi-continuous manufacturing of pharmaceutical products like live virus vaccines, ensuring compliance with cGMP regulations by minimizing particle generation and facilitating thorough cleaning and sterilization.

Implementation Method 1

the drying is done under reduced pressure

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

Microwave vacuum-drying is a drying method that can be employed to dehydrate pharmaceutical biologic materials

Methodology Applied
Scientific EffectMicrowave radiation: Microwave Radiation

Implementation Method 3

a condenser in communication with the drying chamber

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP4161690B1Apparatus and method of microwave vacuum drying sterile products
Publication Date: 2026.03.11 MERCK SHARP & DOHME LLC
  • EP4161690B1 patent drawingFigure 1
  • EP4161690B1 patent drawingFigure 2~3
  • EP4161690B1 patent drawingFigure 4

AI summary

A microwave vacuum dryer includes a loading chamber and a first vacuum pump in communication with the loading chamber, a first door separating the loading chamber from an external environment, a drying chamber adjacent the loading chamber, a second vacuum pump in communication with the drying chamber, and a condenser in communication with the drying chamber, a second door separating the loading chamber and the drying chamber, an unloading chamber adjacent the drying chamber and a third vacuum pump in communication with the unloading chamber, a third door separating the drying chamber from the unloading chamber, a fourth door separating the unloading chamber from the external environment, and a microwave chamber having a plurality of magnetrons, the microwave chamber positioned on a different plane from the loading and unloading chambers and adjacent the drying chamber.