Monograph: |
Chlorbutol
Colourless or white crystals or a white crystalline powder
with a characteristic, somewhat camphoraceous odour. It sub-
limes readily. It melts at about 76Β° to 78Β° for the hemihydrate
and about 95Β° for the anhydrous form. Both anhydrous and
hemihydrated forms are: soluble I in 125 of water. I in I of
alcohol, and I in 10 of glycerol; freely or very soluble in
ether, in chloroform, and in volatile oils. Store at 8* to 15Β° in
airtight containers.
Incompatibilities. The activity of chlorbutol can be ad-
versely affected by the presence of other compounds as well
as by the packaging material. There may be sorption onto
substances like magnesium trisilicate, bentonite, carmellose.
polyethylene, or polyhydroxy-ethylmethacrylate that has
been used in soft contact lenses. Increasing heat or pH
can reduce stability and activity.
Adverse Effects
Acute poisoning with chlorbutol may produce CNS
depression with weakness, loss of consciousness,
and depressed respiration. Delayed (type IV) hyper-
sensitivity reactions have been reported rarely.
Effects on the cardiovascular system. Rapid falls in ar-
terial blood pressure were observed following injections of
heparin with chlorbutol in patients undergoing coronary by-
pass. No fall in blood pressure was seen in patients who re-
ceived preservative-free heparin injection.
Effects on mental function. The sedative effects of
chlorbutol have been reported to be a problem in a patient
dependent on large doses (0.9 to 1.5 g daily with salicylamide
1.8 to 3.0 g daily) and in another patient given high doses of
morphine in an infusion preserved with chlorbutol.
Hypersensitivity. A delayed, cellular type of hypersensitiv-
ity reaction to chlorbutol used to preserve heparin injection
following subcutaneous injection has been reported. Pruritus
from intranasal desmopressin has been reported as due to the
chlorbutol preservative.
Uses and Administration
Chlorbutol has antibacterial and antifungal proper-
ties and it is used at a concentration of 0.5% as a
preservative in injections and in eye drops as well as
cosmetics.
Chlorbutol has been used as a mild sedative and lo-
cal analgesic but other compounds are preferred. It
has been used in preparations for inflammatory and
painful conditions of the ear and oropharynx.
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