Drying

drying is the process of removal of small amount of the liquid (water / volatile liquid / mixture) by application of the heat  to obtain dry solid or solid product .

Operations Involved in the Drying Process:

In general the Drying Process involves two Operations :

1. Heat Transfer :

heat transfer is the transfer of the heat from one material to another by 3 mode of the heat transfer this will lead to removal of the water content and drying of the product .

2. Mass Transfer : 

mass transfer is the transfer  of the mass or the material to from dry product and obtain moisture free content .

Note :  

Drying and Evaporation are relatively the same term but are distinguished in term of the removal of the water.

Drying is the removal of very small quantity of the water but in the process of the evaporation very large quantity of the water is removed leading to giving gout of dry product .  

Drying is the process generally carried out in the solid material example includes powder and products .

In Drying water is usually removed by circulating air over the material in order to carry away the water vapour .

Purpose of Drying :

in pharmaceutical industry the drying is carried out for one or more of the following reason  .

1. to avoid or elemination of the moisture which may lead to corrosion and decrease the drug stability .

2. to improve or keep good properties of the material example may include flowability and compressability .

3. to reduce the cost of the trasportation of large volume of the material usually liquids .

4. to make the material easy or more suitable for handling.

5. the final step in : evaporation - filtration and crysallization .

Application of the Drying :

1. Preservation of the drug roduct .

2. preparation of bulk drug  .

3. improved handling .

4. improved Characteristics .