PRINCIPLE. The main principle involved in freeze drying is a On 21st century, in pharmaceutical field lyophilization has become important. Lyophilization, or freeze drying, is a process in which the solvent (usually water) is: first frozen and then. – removed by sublimation in a vacuum. Freeze drying, also known as lyophilisation or cryodesiccation, is a low temperature . Bulk lyophilization of APIs is typically conducted using trays instead of glass vials. .. Food processing technology: principles and practice ( 4th ed.).

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DRY — Heat energy is then added to the product causing the ice to sublime. Therefore, a vapor trap, or condenser is essential to condense the evolving water molecules.

In many instances the decision to pretreat a product is based on theoretical knowledge of freeze-drying and its requirements, or is demanded by cycle time or product quality considerations. It is necessary to keep the product temperature safely below this critical temperature during primary drying to avoid collapse.

If you examine the curve of Fig 4, you can note that each temperature value for condensed ice corresponds to a vapor pressure, the value of which is always lower than the chamber pressure. Lower lyophklizer are required to freeze and condense solvents and they can easily bypass the condenser and end up causing damage to the vacuum pump.

Basic Principles of Freeze Drying

In shelf freeze dryers, the condenser can be located inside the product chamber internal condenser or in a separate chamber external condenser connected to the product chamber by a vapor port.

Each specific product or formulation that is lyophilized requires the development of a freeze drying process that is based on the unique characteristics of the product, the amount of product and the container used. This ensures that sublimation rather than melting will occur in the following steps. Another tool is available with freeze dryer designs that have external condensers.

Lyophilized products are extremely hydroscopic and they must be sealed in air tight ljophilizer following freeze drying to prevent rehydration from atmospheric exposure.


General Principles of Freeze Drying | American Lyophilizer, INC.

At the pprinciple of the sublimation phase primary dryingall the ice will have disappeared. Product is either pre-loaded into vials which are then transferred to the shelf or it is loaded in bulk form directly onto a product tray.

Since all of the free ice has been removed in primary drying, the product temperature can now be increased considerably without fear of melting or collapse.

It is good practice to characterize the collapse temperature for all new injectable or ingestible drug formulations to be freeze dried. Assuming the optimum rate of flow, an estimate for a dryer of approximately square foot capacity would be:.

When the water content is higher than these levels, the product will denature. Factors affecting secondary terminal drying phase: To resolve certain filling problems.

SP Scientific service professionals offer your organization a depth of expertise that is truly unique to our selected industries and markets. It is important to note that, in this range of pressure, the heat is brought mainly by conduction or radiation; the convection effect is negligible, due to the low air density. Heat is transferred by thermal conduction from the shelf, through the vial, and ultimately into the product.

The drying portion of freeze drying is actually a two part process consisting of Primary Drying and Secondary Drying. Speed of Freezing On the pilot level, fast lhophilizer very fast freezing is relatively easy to achieve. Product temperature sensitivity, and its relation to taste.

Freeze Drying / Lyophilization Information: Basic Principles

To facilitate faster and more efficient freeze drying, larger ice crystals are preferable. Explicit use of et al. A failure in the refrigeration system leads to a chain reaction: Therefore, freeze-drying is often reserved for materials that are heat-sensitive, such as proteinsenzymeslyohpilizerand blood plasma.

Lyophilization avoid denaturation that is caused by heating the product, by maintaining it frozen throughout drying. Equally important is that in liquid-phase drying there is an undesirable shrinkage and concentration of active constituents that causes damage as well as a movement of these constituents to the surface of evaporation, where they form a dense, impermeable skin that inhibits drying, and later, rehydration.


Each manufacturing facility is an ISO If the process is automated it is essential that: Freeze dryer lyophilizef designs are available to provide the lower shelf and condenser temperatures needed to freeze and then condense some organic solvents.

The liquid shelf on which the product is placed. This type of heating allows for simple flat trays to be used as an infrared source can be located above the flat trays to radiate downwards onto the product. Lyophilization significantly reduces damage to biological samples. If a document is made of a variety of materials, which have different absorption properties, expansion will occur at a non-uniform rate, which could lead to deformations.

This can contaminate the product leading to major losses of food product. The Pursuit of Universal Acceptance. Freeze Drying, or lyophilization as it is referred to in the Pharmaceutical and Diagnostic Industries, is a dehydration technique, which enables liquid or slurry products, which have previously been frozen to be dried under a vacuum.

As mentioned earlier, each frozen product has a unique critical temperature. The time of sublimation would be: Determine the total length of the process cycle, including all of the following factors: The refrigeration system cools the ice condenser located inside the freeze dryer.

In this case, the freezing is done rapidly, in order to lower the material to below its eutectic point quickly, thus avoiding the formation of large ice crystals.

It may be difficult, for instance, to divide several milligrams of powder into precise vial dosages, due to the difficulty of measuring tiny amounts, homogeneity, granulation, static electricity etc.

Freeze-dried pharmaceutical products are produced as lyophilized powders for reconstitution in vials and more recently in prefilled syringes for self-administration by a patient. In addition to defrosting the condenser and cleaning the system after each cycle, routine freeze dryer maintenance typically includes periodic changing of vacuum pump oil and visually checking all seals and gaskets.

For the Batman episode, see Instant Freeze.