Tohmina Khatun Nasir UddinID:20140107021 Lecturer Dept. of ACCE Dept. of ACCE

BSMRSTU BSMRSTU My Presentation Topic is

What is crude drugs?

A crude drug is any naturally occurring, unrefined substance derived from organic or inorganic sources such as plant, animal, bacteria, organs or whole organisms intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease in humans or other animals.

General methods of extraction of crude drugs

coarsely powdered crude drug is placed in a stoppered container with the solvent and allowed to stand at room temperature for a period of at least 3 days until the soluble matter has dissolved.There are several methods for crude extraction: Maceration Infusion Digestion Decoction Percolation Hot Continuous Extraction (Soxhlet) Aqueous Alcoholic Extraction by Fermentation Counter-current Extraction Ultrasound Extraction (Sonication) Supercritical Fluid Extraction Phytonics Process

Maceration:In this process, the whole or coarsely powdered crude drug is placed in a stoppered container with the solvent and allowed to stand at room temperature for a period of at least 3 days until the soluble matter has dissolved. The mixture then is strained, the marc is pressed, and the combined liquids are clarifi ed by filtration.

Infusion :Fresh infusions are prepared by macerating the crude drug for a short period of time with cold or boiling water. These are dilute solutions of the readily soluble constituents of crude drugs.

Digestion :This is a form of maceration in which gentle heat is used during the process of extraction. It is used when moderately elevated temperature is not objectionable. The solvent effi ciency of the menstruum is thereby increased.

Decoction:In this process, the crude drug is boiled in a specified volumeof water for a defined time; it is then cooled and strained or filtered. Thisprocedure is suitable for extracting water-soluble, heat-stable constituents.

Separation and isolation of constituents

The most difficult operation in phytopharmacetical research is the isolation and purification of plant constituents. The physical methods used are chromatographic techniques and methods such as• fractional crystallysation,• fractional distillation,• fractional liberation.Fractional crystallysation : It is an important method for the purification of compounds from mixture. It depends upon the compound which form crystals at the point of super saturation in the solvent in which it is soluble Many natural products are crystaline nature .Fractional distillation: This method is used for the separation of the components from volatile mixtures . Largely using in the separation of hydrocarbons from oxygenated volatile oil eg citral, eucalyptol Sublimation: Here the compound is heated the solid state changes to gaseous state without passing via liquid state. Such compounds get deposited in form of crystals or cake.Chromatograpy: Chromatography is widely used for the separation & identification of components of a mixture. Separation of chemical compounds is carried out by mobile phase and stationary phase. Chromatography can be classified according to mechanism of separation as: • adsorption chromatography,• partition chromatography,• ion exchange chromatography,• size exclusion chromatography and • affinity chromatography.