What Is Freeze Drying

the freeze drying process was invented in 1906 by the French. However, a similar dehydration system was already used by the Andes Indians to dry food, especially meat at high altitude and this because of the low atmospheric pressure.

1 ° / Freeze-drying principle:

Freeze-drying consists in removing water from a liquid, pasty or solid product by freezing or freezing and evaporating under vacuum. When heating water in the solid state and at very low pressure, the water sublimates and goes into the gaseous state (water vapor). This water vapor that is released from the solid product is trapped on a condenser or trap.

This technology allows not to alter the quality of the product that is freeze-dried. It is the only drying method that perfectly preserves the molecular structure of the different molecules that make up the product. For example, in our case, the molecules that make up our proteins are totally preserved in their native state, the vitamins are not destroyed, the different freeze-dried micro-organisms are “revivifiable”.

2 ° / The different freeze drying phases:

  • The products are frozen, the water turned into ice.
  • Primary drying or sublimation or freeze drying. It consists in sublimating the interstitial ice; causes the evaporation of the water vapor which is fixed on a special coil which is at a temperature between -60 and -70 ° C.
  • Secondary drying. It consists of a heating operation. The maximum temperature is + 50 ° C.

This freeze drying technique allows us to obtain dehydrated products with an extremely low humidity rate between 1 and 5%.

In the operation of freeze dryers two phases are extremely important:

  • Freezing: this phase must allow to block the water in the form of solid ice and not in the form of ice in small crystals.
  • The vacuum: the quality of the vacuum is the most important phase of freeze-drying. The freeze dryers must be perfectly sealed (structures, valves …). Vacuum pumps must have sufficient air debt to maintain a perfect vacuum.

3 ° / Industrial

freeze- drying: The products to be freeze-dried can come in different forms. The main ones are:

  • Loose form in trays
  • In bottles
  • In blisters or jars

All our freeze dryers are steam sterilizable.
All our freeze dryers can be used for pharmaceutical production.

At present there are various drying methods that are used in the pharmaceutical world in making pharmaceuticals available. These methods are:

1.Tray Dryer.

The drying method with tray dryer is an old drying method but is often used for drying solids, granules, powders or granules which are not too large

2. Fluid Bed Dryer.

Drying methods which are required for relatively light weighted materials, for example powder and ganular. Making it suitable for drying crystalline materials, granules, abrasive medicines, both chemicals, dyes and food. Fluid bed dryers are not suitable for drying paste and liquid materials.

3. Dry Drying.

Spray drying is a drying process by exposing liquid particles ( droplets ) to hot gas bursts with temperatures higher than droplet temperatures. This method is the oldest type of drying and is often used in the pharmaceutical industry. This method is used to convert pastes, porridge or low-viscosity liquids to dry solids.

4. Vacuum Dryer.

Vacuum is the process of removing water from a material, together with the use of heat, vacuum can be an effective drying method. Drying can be achieved in lower temperatures so it is more energy efficient. This method is suitable for drying heat-sensitive or volatile materials due to their short drying time.

5. Freeze Drying .

Freeze drying is a drying method that has the advantage of maintaining the quality of drying results, especially for products that are sensitive to heat.

Of all these methods, one of the best drying methods currently is the freeze drying method or better known as the freeze drying method. This method is also known by various names such as lyophilisation, lyophilization and cryodesiccation methods.

The basic principle of freeze drying (freeze drying) is the process of removing the water content in a change or product that has been frozen (ice) without going through the liquid phase first. Lyophilization is a pharmaceutical solution for producing a stable powder product. This method has become a standard practice in producing injectable dosage products on the market.

To get a good product with the Frezee drying method requires special equipment called Freeze Dryer. Freeze dryer is a drying device that is included in the  Conduction Dryer / Indirect Dryer  because the transfer process occurs indirectly, ie between the material to be dried (wet material) and the heating media there is a dividing wall so that the water in the wet / moist material that evaporates is not carried together heating media. This shows that heat transfer occurs by conduction.

The stages that occur in the freeze dryer machine, as follows:

  • Freezing: The product to be dried is previously frozen first.
  • Vacuum: After freezing, this product is placed under vacuum. This allows the frozen solvent in the product to evaporate without going through the liquid phase, a process known as sublimation.
  • Heat: Heat is applied to frozen products to accelerate sublimation.
  • Condensation: Condensers with low temperatures will remove the solvent that evaporates in the vacuum chamber by converting it back to solid.

The advantages of the product using the freeze drying method compared to other methods include:

  • The resulting product will be more stable quality (no change in aroma, color, and other organoleptic elements)
  • The structure of the material in the product remains stable (no shrinkage or deformation of the material structure)
  • The rehydration power of the product increases (with drying results that are very hollow and lyophile so that the rehydration power is very high and can return physiological, organoleptic and physical form which is almost the same as before drying).

This rehydration power is very important in the pharmaceutical industry, especially for injection drug preparations. The higher the rehydration power, the better the solubility or solubility of the product.

These advantages can of course be obtained if the frozen drying procedures and processes are applied precisely and in accordance with the characteristics of the dried material. Certain operational conditions that correspond to one type of product do not guarantee it will be compatible with other types of products.

By looking at these advantages, a South Korean company, Woogene B&G, made an injection preparation with an active ingredient in the form of Ceftiour Sodium named after the trade brand PaXXcell using the Freeze Drying method.

The Woogene plant itself has been certified by KVGMP (Korean Veterinary Good Manufacturing Practice) and APVMA GMP (Australian Pesticides & Veterinary Medicines Authority – Good Manufacturing Practice, Good Process of Pesticides and Animal Drugs from Australia) so the quality of the product itself can be maintained and guaranteed.

To get a pharmaceutical preparation that is good and quality, we must be careful in choosing it. Here are some requirements that can be taken into consideration:

  1. Free from microorganisms, sterile or made from sterile materials under conditions that lack a combination of micro organisms (aseptic process).
  2. Ingredients free from bacterial endotoxins and other pyrogenic materials.
  3. Ingredients that are free from foreign substances that are insoluble outside.
  4. Sterility
  5. Free from particulate matter
  6. Free of Pyrogen
  7. Stability
  8. Injection is asotonic as possible with blood.

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