Monograph: |
Tannic Acid
A tannin usually obtained from nutgalls, the excrescences
produced on the young twigs of Quercus mfectoria and allied
species of Quercus. from the seed pods of tara {Caesatpinia
spinosa). or from the nutgalls or leaves of sumac (any of ge-
nus Rhus).
Commercial grades of tannic acid may contain gallic acid and
being less soluble are not suitable for medicinal use.
Yellowish-white or light brown glistening scales, spongy
masses, or an amorphous powder, odourless or with a charac-
teristic odour.
Very soluble in water, alcohol, and in acetone: soluble I in I
of warm glycerol; practically insoluble in chloroform, ether,
and petroleum spirit. Store in airtight containers. Protect
from light.
Tannic acid has been used as an astringent for the mucous
membranes of the mouth and throat. Suppositories containing
tannic acid have been used in the treatment of haemorrhoids.
It is an ingredient in a number of dermatological preparations.
Former uses of tannic acid include its application to burns and
its addition to barium sulphate enemas to improve the quality
of the pictures in the radiological examination of the colon.
Both of these uses were associated with liver toxicity, some-
times fatal.
Although tannic acid may be used by plastic surgeons and
dermatologists to produce a controlled partial-thickness burn
in tattoo removal it has been pointed out that in unskilled or
amateur hands this procedure has resulted in full thickness
burns requiring skin grafting to obtain satisfactory healing.
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