Preservation of crude drugs needs sound knowledge of their physical and chemical properties. A good quality of the drugs can be maintained, if they are preserved properly.
STORAGE OF CRUDE DRUGS
Preservation of crude drugs needs sound knowledge of their
physical and chemical properties. A good quality of the drugs can be
maintained, if they are preserved properly. All the drugs should be preserved
in well closed and, possibly in the filled containers. They should be stored in
the premises which are water-proof, fire proof and rodent-proof. A number of
drugs absorb moisture during their storage and become susceptible to the
microbial growth. Some drugs absorb moisture to the extent of 25% of their
weight. The moisture, not only increases the bulk of the drug, but also causes
impairment in the quality of crude drug. The excessive moisture facilitates
enzymatic reactions resulting in decomposition of active constituents e.g.
digitalis leaves and wild cherry bark. Gentian and ergot receive mould
infestation due to excessive moisture. Radiation due to direct sun-light also
causes destruction of active chemical constituents, e.g. ergot, cod liver oil
and digitalis. Form or shape of the drug also plays very important role in
preserving the crude drugs. Colophony in the entire form (big masses) is
preserved nicely, but if stored in powdered form, it gets oxidized or looses
solubility in petroleum ether. Squill, when stored in powdered form becomes
hygroscopic and forms rubbery mass on prolonged exposure to air. The fixed oil
in the powdered ergot becomes rancid on storage. In order to maintain a good
quality of ergot, it is required that the drug should be defatted with lipid
solvent prior to storage. Lard, the purified internal fat of the abdomen of the
hog, is to be preserved against rancidity by adding siam benzoin. Atmospheric
oxygen is also destructive to several drugs and hence, they are filled
completely in well closed containers, or the air in the container is replaced
by an inert gas like nitrogen; e.g. shark liver oil, papain, etc.
Apart from protection against adverse physical and chem-ical
changes, the preservation against insect or mould attacks is also important.
Different types of insects, nematodes, worms, moulds and mites infest the crude
drugs during storage. Some of the more important pests found in drugs are
Coleoptera (Stegobium paniceum and Calandrum grana-rium), Lepidoptera (Ephestia kuehniella and Tinea pellionella), and Archnida or
mites (Tyroglyphus farinae and Glyophagus domesticus). They can be prevented by drying the drug thoroughly before storage and also by
giving treatment of fumigants. The common fumigants used for storage of crude
drugs are methyl bromide, carbon disulphide and hydrocyanic acid. At times,
drugs are given special treament, such as liming of the ginger and coating of
nutmeg. Temperature is also very important factor in preservation of the drugs,
as it accelerates several chemical reactions leading to decomposition of the
constituents. Hence, most of the drugs need to be preserved at a very low
temperature. The costly phytopharmaceuticals are required to be preserved at
refrigerated temperature in well closed containers. Small quantities of crude
drugs could be readily stored in air-tight, moisture proof and light proof
containers such as tin, cans, covered metal tins, or amber glass containers.
Wooden boxes and paper bags should not be used for storage of crude drugs.
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