US Pharm. 2013;38(11):49-50.
Method of Preparation: Calculate the quantity of
each ingredient for the amount to be prepared. Accurately weigh or
measure each ingredient. Mix together the pyrogallol, ferric chloride
tincture, and acetone. Add sufficient alcohol 95% to final volume and
mix well. Package and label.
Use: This preparation has been used as a marking solution prior to varicose vein procedures.
Packaging: Package in tight, light-resistant containers.
Labeling: Keep out of reach of children. Discard after ____ [time period]. For external use only.
Stability: A beyond-use date of 30 days may be used for this preparation.1
Quality Control: Quality-control assessment can include
weight/volume, pH, specific gravity (SG), active drug assay, color,
clarity, rheologic properties/pourability, physical observation, and
physical stability (discoloration, foreign materials, gas formation,
Discussion: Pyrogallol (pyrogallic acid, C6H6O3,
MW 126.11) occurs as light, white, or nearly white, odorless leaflets
or fine needles. It acquires a grayish tint upon exposure to air and
light. When exposed to air, a solution of pyrogallol acquires a brown
color and an acid reaction due to oxidation by air. This reaction
proceeds more rapidly if the solution is alkaline. Pyrogallol has a
melting point between 130°C and 133°C. It is used as a local
antibacterial and local irritant, and it is an irritating skin
antiseptic. Pyrogallol is soluble 1 g in 1.7 mL of water and 1.3 mL of
alcohol. Aqueous solutions of pyrogallol oxidize and darken upon
exposure to air, particularly if the solution is alkaline; the change is
hastened by oxidizing agents. As with other phenolic compounds,
pyrogallol provides coloration with iron salts. In neutral solution,
pyrogallol forms precipitates with the salts of many metals.
Ferric chloride tincture (iron tincture) consists of ferric chloride
solution (350 mL) made to volume with a sufficient quantity of alcohol
to yield 1,000 mL. Ferric chloride tincture is a yellowish-orange liquid
with a slightly ethereal odor, a highly astringent taste, and an acid
reaction; it contains about 58% to 64% alcohol. Formerly, ferric
chloride tincture was taken orally as a hematinic, but it is rarely used
for this purpose today. It has been used locally as a styptic in
Ferric chloride solution is an aqueous solution containing in each
100 mL not less than 37.2 g and not more than 42.7 g of iron(III)
chloride, and not less than 3.85 g and not more than 6.6 g of hydrogen
chloride. Ferric chloride solution is a yellowish-orange liquid with a
faint odor of hydrochloric acid and an acid reaction. It is affected by
light. Ferric chloride solution has been used as a hemostatic; its
principal use, however, is as a pharmaceutical necessity to form (by
dilution with alcohol) ferric chloride tincture.
Acetone (2-propanone, dimethyl ketone, C3H6O,
MW 58.08) occurs as a transparent, colorless, mobile, volatile liquid
with a characteristic odor. Formerly, it was obtained from the
destructive distillation of wood; the distillate consisted principally
of methanol, acetic acid, and acetone, which was neutralized with lime,
and acetone was separated from the methanol by fractional distillation.
Acetone is now largely obtained as a by-product of the butyl alcohol
industry. A 50% aqueous solution is neutral to litmus. Acetone is
miscible with water, alcohol, ether, and most volatile oils; it has an
SG of not more than 0.789 and a boiling point of about 56°C. Acetone is
used as a solvent or cosolvent in topical preparations up to a
concentration of 13%, and as an aid in wet granulation. It is also used
as an antiseptic and cleansing agent (in combination with alcohol).1,3
Alcohol 95% (ethyl alcohol, ethanol, grain alcohol, C2H5OH,
MW 46.07) is a clear, colorless, mobile, volatile liquid with a slight,
characteristic odor and a burning taste. It is used as an antimicrobial
preservative (>10% concentration), a disinfectant (60-90%
concentration), a solvent in injectable and oral liquids (variable
concentration), and a solvent in topical products (60%-90%
concentration). Alcohol USP refers to 95% ethanol; dehydrated alcohol
refers to 99.5% alcohol. Alcohol’s SG is between 0.812 and 0.816, and
its boiling point is 78.15°C. Alcohol is miscible with chloroform,
glycerin, and water, and its solutions may be sterilized by autoclaving
or filtration. It should be stored in a cool place. Alcohol is
incompatible with oxidizing materials in acidic conditions. With
alkalies, it may darken in color. When it is added to aqueous solutions
of organic salts or acacia, they may precipitate. Alcohol is
incompatible with aluminum containers, and it may interact with some
1. U.S. Pharmacopeia 36/National Formulary 31. Rockville, MD: U.S. Pharmacopeial Convention, Inc; 2013:335-398,1240.
2. Allen LV Jr. Standard operating procedure for performing physical quality assessment of oral and topical liquids. IJPC. 1999;3:146-147.
3. Kibbe AH. Acetone. In: Rowe RC, Sheskey PJ, Cook WG, Fenton ME, eds. Handbook of Pharmaceutical Excipients. 7th ed. London, England: Pharmaceutical Press; 2012:7-8.
4. Fenton ME. Alcohol. In: Rowe RC, Sheskey PJ, Cook WG, Fenton ME, eds. Handbook of Pharmaceutical Excipients. 7th ed. London, England: Pharmaceutical Press; 2012:19-22.
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