Page 226 - PG 101-Course notes مذكرة النظري 24-25 with spec

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

Drying of crude drugs

o Fresh plants usually contain high percentage of moisture (up to 80 or 90%).

Drying is the removal of water or most of it from fresh living tissues. The

duration of drying process varies from a few hours to many weeks. Moisture

must be removed in order to:

▪ Stop the enzymatic action that might change the active constituent, i.e., to fix

the active constituents.

▪ Avoid deterioration upon storage by preventing the growth of

microorganisms (bacteria and fungi).

▪ Facilitate packing and storage.

▪ Lower the transportation cost as the weight of the drug is greatly reduced.

▪ Facilitate grinding of drug.

Careful drying is also essential in order to obtain drugs which:

• Retain their physical characters.

• Retain their chemical constituents.

• Complying the pharmacopoeia requirements for maximum moisture contents.

The most important factors in drying process are temperature and time:

• To use as low temperature as possible.

• To carry out the operation as rapid as possible.

There is an optimum combination of temperature and time factors for each drug.

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