Page 446 - Applied Pharmacognosy

Types of Chemical markers

• b – dry in a desiccator over P2O5 under atmospheric pressure and at

room temperature

• eg : balsams …
• c – vacuum drying over an absorbent which may be utilized at specified

temperature (heating at reduced pressure).

• eg: colchicine, digoxin, ergometrine maleate...
• b and c are used for drugs that are thermally unstable, or contain

volatile materials.

• Calculate the loss in weight in mg / gm of air- dried material.

•