Drying :-

• The process of Removal of water or any solvent from a substance by evaporation is called Drying.
• Source of evaporation is heat.

Importance of drying in pharmaceuticals:-

• This process is mostly used as a finals production step before packing the products .
• Dry products is more stable than moist one.
• Drying increase the stability of drug.

Equipments used for drawing :-

1. Belt dryer
2. Vaccume tray dryer

Belt dryer :-

Belt dryers mostly used for the drying of:

1. Chemicals
2. Granules
3. Food items
4. Raw material in pharma industries

Principal of belt dryer :-

Liquid is removed from material by using heat.

Parts of belt dryer:-

• Heating plates
• Horizontal conveyor belt
• Pully
• Feeding point
• Collecting point
• Control panel

Working of belt dryer :-

• The material is evenly spread on the conveyor belt by feeding device.
• Movement of belt is controlled by a control panel.
• Dry air is transported by the fan on the material from top to bottom or bottom to top position.
• The drive material is pushed into collecting point.

Vacuum tray Drayer :-

• The apparatus is used to dry oxygen sensitive and hygroscopic products.
• It is most commonly used batch dryer.

Parts of vacuum tray dryer:-

1. Steam or water jacket
2. Condenser
3. Tray
4. Vacuum pump
5. Door

Working of vacuum tray dryer:-

• Vacuum is applied inside the chamber .
• It is a box shape apparatus with door.
• Trays are placed in the chamber on which material to be dried is placed.
• Because of vacuum boiling point of liquid decrease.
• By conduction mechanism heat is transferred to the material placed on trays.
• Vapours passed through condenser then condensate collected into receiver.
• Then collect dried sample from the trays.