LAB #3 Flashcards
What is the title of experiment number 3
Extraction and recrystallization
A process that selectively dissolves one or more compounds into an appropriate solvent the resulting solution is called an extract
Extraction
It refers to the transfer of compounds from one liquid solvent to another one
Extraction
Can be used to separate unwanted impurities or to separate mixtures of compounds
Extraction
The two solvents used for extraction must be____
Immiscible
Can be defined as the preparations of crude drugs which contain all the constituents which are soluble in the solvent
Extract
It is the solid residue obtain after extraction
Marc
It is the solvent used for extraction
Menstruum
Principles of extraction
To pull out a compound from one layer into another
A compound partitions more toward where it is more soluble (equilibrium)
Multiple extractions may be needed to completely extract a substance
Factors affecting extraction process
Nature of drug
Solvent
Temperature
pH
Particle size
Methods of extraction
Infusion
Decoction
Digestion
Maceration
Percolation
Continues hot extraction
These are prepared by macerating the crude drug for a short period of time with cold or boiling water
Fresh infusions
These are dilute solutions of the readily soluble constituents of crude drugs
Infusion
Two types of infusion
Fresh infusion
Concentrated infusion
Example given for fresh infusion
Infusion of orange
Example given for concentrated infusion
Concentrated infusion of quassia
In this process the crude drug is boiled in a specified volume of water for the fine time it is then cooled and strained for filtered
Decoction
This procedure is suitable for extracting water soluble heat stable constituents
Decoction
This is a form of maceration in which gentle heat is used during the process of extraction
Digestion
It is used when moderately and elevated temperature is not objectionable
Digestion
During this process the solvent efficiency of the menstruum is there by increased
Digestion
Example given for digestion
Extraction of morphine
In this process solid ingredients are placed in a stoppered container with a hole of the solvent and allowed to stand for a period of at least 3 days with frequent agitation until soluble matter is dissolved
Maceration
The mixture is then strained through sieves or nets where the mark pressed and the combined liquids clarified or cleaned by filtration or by decantation after standing
Maceration