Page 481 - Applied Pharmacognosy

• The amount of an extract that a drug yields in a
particular solvent is often an approximate

measure of the amount of certain constituents that the
drug contains.

• This method determines the amount of active constituents

in a certain weight of a medicinal plant material through
extraction with suitable solvent.

• The solvent chosen is based on the degree of solubility of

the active constituents.

• Example the determination of water – soluble , ethanol –

soluble or petroleum ether – soluble extractives.