Ellab Tracksense Pro logger for LYOPHILIZATION

Mô tả

Ellab Tracksense Pro logger for LYOPHILIZATION

Real time wireless datalogging in Freeze Drying Applications

Brand: Ellab – Denmark

Introduction:
Lyophilization (Freeze drying) is a process in which water is removed from a  product under extremely low temperatures using a vacuum. To control this process it is essential that accurate temperature measuring systems are used. A wireless system is preferred
over cable based system to avoid jeopardizing the integrity of the high vacuum utilized in the freeze drying chamber. Depending on the logger, the Sky Module has a temperature range of -80° to 140° C and allows real-time data to be viewed while the application is running.
Both product and shelf temperatures can be monitored simultaneously using Ellab fl exible sensors. This combined with their high durability makes TrackSense® loggers and sensors a unique solution to this challenging application.

Freeze drying (or lyophilization) is a technique used to remove water from a solution to leave a dry ‘cake’ as an end product. The dry product is much more stable than a solution. The reduced weight and volume is a big advantage and the removal of the water does not change the activity of the product. This technique involves freezing the product on a shelf to very low temperatures, typically –40 to –50°C, applying a vacuum and then slowly heating the product to ensure the ice turns into vapor and this removes the water content from product by a process called sublimation.

The critical parameters during freeze-drying are temperature (product and shelf) and pressure. These measurements are usually recorded with every cycle to determine when the product is dry. In addition to monitoring each cycle, freeze driers also require regular validation. This will generally involve temperature mapping of the shelves in the chamber, condenser cool down test, system evaluation test (Vacuum Pull-Down) to test Vacuum pumping system efficiency and Vacuum integrity test to show quality of seals, as well as validation of steam supplies for SIP system.

As freeze drying is a rather expensive process most products being processed are within the pharmaceutical and biotechnology area where companies often use freeze-drying to increase the shelf life of products, such as vaccines and other injectables. By removing the water from the material and sealing the material in a vial, the material can be easily stored, shipped, and later reconstituted to its original form for injection.

You can still find lyophilization performed in other areas :

Food industry (example: freeze dried fruits, astronaut food supplies, instant coffee).

Technological industry:
• In chemical synthesis to make them more stable, or easier to dissolve in water for subsequent use.
• In bioseparations as a late-stage purification procedure to remove solvents.
In bacteriology to conserve special strain.

Conservation and preservation industry:
• Flowers
• Animals
• Water damaged books and documents

The Ellab solution:
The Tracksense® Pro wireless system covers the complete process including vial preparation,vial probing and shelf measurements throughout the Lyophilization process, as well as the required between-batch CIP/SIP validations. Using wireless data loggers eliminates the need for feed-throughs and thermocouples, thus avoiding possible leaks and saving hours of valuable time during installation and set up.
PROCESS EQUIPMENT

A freeze dryer consists of three main components: sample chamber, condenser and a vacuum pump system. Depending on what should be dried, the sample chamber that is directly connected to the condenser and vacuum pump is designed with an appropriate number of shelves which can be moved up and down if closing of vials is requested. This is called the stoppering arrangement. There are essentially two categories of freeze-dryers: batch and continuous dryers.

Batch freeze dryers are designed either for bulk drying where product is distributed onto trays or vial drying where product is dispensed into flasks(vials) using special rubber stoppers with vapor “escape” holes (slots). The benefit of this container is that the product can be easily reconstituted by simply adding liquid. For both systems batch monitoring can be done either by using the E-Val Flex cabled system or TrackSense® wireless loggers. Due to the fact that maintaining a high vacuum is essential for all lyophilization processes, the use of wireless loggers is highly recommended. A configuration with Pro-X loggers, low temperature multi channel flexible sensors in combination with the SKY module and Access Point outside chamber is an ideal solution. Due to the high vacuum (~ 0.005 hPa) only wireless loggers with Ellab Vacuum Sensor can be used to monitor the Vacuum Level.

Continuous freeze dryers are designed for vial drying and complete filling, loading and unloading systems which are integrated in the freeze dryer design. This allows fully automatic and sterile manufacturing with in-between batch sterilization (SIP) of the freeze dryer. This will exclude the use of cabled systems but again Pro-X loggers fitted with low temperature multi channel flexible sensors is recommended. To cover the SIP part of the process, standard multi channel flexible sensors are needed. The SKY option can be advantageous if distances are not too long.

CHALLENGES

As product volume can be very small it is essential that the sensor that measures sample temperature during processes can be introduced without jeopardizing the integrity and thus very slim temperature sensors are needed. Ellab has developed a range of low temperature flexible sensorswith a diameter of only 1.2 mm which can be easily inserted in the vial through the rubber stopper. For chamber validation a contact puck made of brass is available to secure paramount contact between the shelf and sensor ensuring correct readings. For easy operation a “LYO Shuttle” Fixture is ideal incorporating both vial fixation as well as contact puck.

The main challenges associated with monitoring freeze driers are the low temperatures and the low pressures present. The low pressures (around 5 microbar) restrict the ability to introduce cables into the chamber while still maintaining a good (high) vacuum, so for practical use, only wireless loggers fitted with Vacuum sensor are recommended. The vacuum is much more difficult to maintain than high pressure. However, the low temperatures used can make it difficult for some data loggers to function. TrackSense® Pro-X and the Pro battery can be used in temperatures down to –80°C. The unique battery management system, the design of the logger and the flexible sensors make them suitable for almost all freeze drier cycles, overcoming problems associated with the low temperatures.

GUIDELINES

The ISO 13408-3 standard describes Aseptic processing of healthcare products with regards to Lyophilization. Because the freeze drying process is so delicate and complex it is absolutely essential to be able to follow the process in real time. With the recent introduction of SKY this is now possible. TrackSense® Pro X loggers with PTFE flexible sensors and vacuum sensor is a unique solution and the live transmission of data from all temperature loggers placed inside to Access Point placed outside the chamber is a trouble free setup providing accurate and instant process control and documentation. The usual number of temperature measuring points during process monitoring could be as high as one sensor placed in a representative sample (vial or tray) per shelf. Often only one Vacuum sensor is required.

For validation of the chamber the usual number of temperature measuring points is five for each shelf – one in each corner plus one in center. Usually, the cross shelf stability (homogenity) required is ±0,5°C to 1°C and shelf-to-shelf variation is 1°C to 2°C. As freeze dryers are often equipped with 10-15 shelves or more it is essential that the logging hardware and analyzing software can handle data of that magnitude. With a storage capacity of 60.000 data points in each logger and ValSuite™ Pro software which can handle more than 100 channels in each session this is easy to match.

METHOD

Low Temperature Sensors

 

• Document: Data Report