Freeze dryer PPT

DOWNLOAD PPT HERE

Freeze dryer PPT :

Drying is a important method used in the pharmaceutical industry. drying can prevent deterioration of the product and enhances the solubility. It is applied to the removal of small amounts of water or other liquid from solids by the heat application . water Vapour is removed at temperatures below the boiling point of water.

EQUIPMENTS USED IN DRYING PROCESSES Tray dryer Spray dryer Fluid bed dryer Vacuum dryer Drum dryer FREEZE DRYER

FREEZE DRYER : (lyophilization ) Principle: water is removed from the frozen state by sublimation. The drying is achieved by exposing the product to temperature and pressures below the triple point. In these conditions heat transferred is used as latent heat and ice sublimed directly into vapour state.

CONSTRUCTION : It consists of Vacuum chamber Heat supply in the form of radiation source, heating coils 3) Vapour condensing or adsorption system. Vacuum pump or steam ejector or both. The distance between subliming surface and condenser must be less than the mean path of molecules. That increases the rate of drying. The temperature of the condenser must be lower than the evaporated surface of frozen substance .

WORKING : It consists of the following steps : 1) Preparation and pretreatment 2) pre freezing for solidifying water 3) primary drying ( sublimation of ice under vaccum) 4) Secondary drying ( removal of residual moisture under high vacuum) 5) packing

Preparation and pretreatment: The volume of solution introduced into the flask is limited by its capacity Satisfactory freeze drying is not possible because of the certain limit of dept so pretreatment is essential. The solution is pre concentrated under normal vacuum tray drying. This reduces the actual drying by 8 to 10 times. The final product becomes more porous.

 Pre freezing to solidify water: Vials, ampoules or bottles in which the aqueous solution is packed are frozen in cold shelves about - 50ْ C During this stage , cabinet is maintained at low temperature atmospheric pressure . the normal cooling rate is about 1 to 3 kelvin / min

Primary drying : the material to be dried is spread as much large surface as possible for sublimation. temperature and pressure should be below the triple point of water i.e, 0.0098ºC and 0.533 kilopascals for sublimation . vacuum is applied to the tune of about 3mm Hg on the frozen sample. the temperature is linearly increased to about 30ºC in a span of 2 hr. heat is transfer as latent heat and ice sublimes directly into vapour state. as soon as vapour molecules are formed these are removed .

Secondary drying ( removal of residual moisture under high vacuum): traces of moisture is removed but temperature of solid is raised to as 50 to 60ºC. But vacuum is lowered below that is used in primary drying 5 ) packing:

Uses : It is most commonly used in the production of dosage forms, such as injections, solutions and suspensions. it is used for drying of a number of products. 1) Blood plasma and its fractionated products. 2) Bacterial and viral cultures. 3) Human tissue ( arteries and corneal tissue). 4) Antibiotics and plant extracts. 5) Steroids, vitamins and enzymes.

Advantages: The entire operation is carried out well below the freezing point. 1) Thermolabile materials can be dried. 2) Denaturation does not occur. 3) Loss of volatile material is less. 4) Sterility can be maintained. 5) Material can be dried in its final container such as single dose and multiple dose vials.

Disadvantages: 1) Equipment and running costs are high. 2) It is difficult for solutions containing non aqueous solvents. 3) The period of drying is high. Time cannot be shortened.

Submitted by  :Mrs.Dhanalakshmi

• Tweet
• Share
• Share
• Share
• Share

About Admin

Hello Visitors. Welcome to this blog .For any queries related to pharma please feel free to contact us at on our mail pharmastuff.blogspot.com@gmail.com

Related Post