Page 231 - PG 101-Course notes مذكرة النظري 24-25 with spec

Medicinal plants (PG 101) Level 1 Clinical Pharmacy-PharmD

Factors responsible for deterioration of crude drugs :

I. Physicochemical factors:

a. Moisture: this may cause hydrolysis of the active constituents by enzymes, (e. g.

digitalis leaf over 5% humidity) and aids the growth of bacteria and fungi, to overcome

the effect of moisture, stabilization of drugs may be carried out to inhibit the enzymatic

action. Stabilization may be temporary by putting the drugs in containers, enclosing,

dehydrating agents such as quick lime or calcium chloride, or complete by destroying

enzymes by subjecting the fresh drug to alcohol vapor or immersing it in hot alcohol.

b. Temperature: the slight rise in temperature above the normal will activate the

enzymatic action (usually occur at about 35 to 45 C). Drugs containing volatile oils
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such as buchu, ginger, clove and chamomile are directly affected with rise in

temperature.

c. Light: this affects delicate drugs having colors e. g. rose petals which are red when

fresh changing to brown on exposure to light, and digitalis leaf which may lose their

active constituents on exposure to sunlight These drugs must be stored in dark brown

containers away from light.

d. Air: Oxygen of air has a definite oxidation effect on the active constituents of some

drugs such as colophony and linseed oil.

The general rule for preservation of drugs is to store them in moisture- proof, air-

tight containers at low temperature. In few cases the drug may be kept in nitrogen

atmosphere.

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