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US Pharm. 2012;37(10):38-39.
Method of Preparation: Calculate the required
quantity of each ingredient for the total amount to be prepared.
Accurately weigh or measure each ingredient. Heat about 75 mL of
purified water to about 75°C; add the methylparaben, propylparaben, and
methylcellulose 1,500, and mix until dissolved. Cool the solution to
room temperature and add the neomycin sulfate, benzoic acid, glycerin,
sodium cyclamate, sodium phosphate, and cherry flavor; mix until
dissolved. Adjust the pH to the range of 5.0 to 7.5 using sulfuric acid
10% solution, if necessary. Add sufficient purified water to final
volume and mix well. Package and label.
Use: Neomycin sulfate oral solution has been
used for bowel preparation before abdominal surgery and for selective
treatment of digestive-tract problems in patients in ICUs.
Packaging: Package in tight, light-resistant containers.1
Labeling: Keep out of the reach of children. Use only as directed. Shake well.
Stability: A beyond-use date of 14 days when stored in a refrigerator may be used for this preparation.1
Quality Control: Quality-control assessment can
include weight/volume, pH, specific gravity, active drug assay, color,
rheologic properties/pourability, physical observation, and physical
stability (discoloration, foreign materials, gas formation, mold
growth).2
Discussion: Neomycin sulfate is an aminoglycoside antibiotic obtained from cultures of Streptomyces fradiae.
It occurs as a white to slightly yellow hygroscopic powder that is
freely soluble in water and very slightly soluble in alcohol. Neomycin
sulfate has a potency equivalent of not less than 600 mcg of neomycin
per mg, calculated on the dried basis.1
Benzoic acid (C7H6O2, MW 122.12)
occurs as white crystals, scales, or needles. It has a slight odor,
usually suggesting benzaldehyde or benzoin. Benzoic acid is freely
volatile in steam, freely soluble in alcohol, and slightly soluble in
water.1,3
Glycerin (glycerol, 1,2,3-propanetriol, C3H8O3,
MW 92.10) occurs as a clear, colorless, odorless, viscous, hygroscopic
liquid. It is miscible with water, methanol, and 95% ethanol. Glycerin
is practically insoluble in oils and slightly soluble in acetone.4
Sodium cyclamate (C6H12NNaO3S, MW
201.22) occurs as white, odorless, or almost odorless crystals or as a
crystalline powder with an intensely sweet taste. Sodium cyclamate is
soluble 1 g in 5 mL of water, 1 in 25 of propylene glycol, and 1 in 250
of 95% ethanol. Its solutions are stable to heat, light, and air over a
wide pH range.5
Sodium phosphate (Na3PO4, MW 163.94
[anhydrous], 181.96 [monohydrate], 380.13 [dodecahydrate]) occurs as
white, odorless crystals or granules or as a crystalline powder. Sodium
phosphate is freely soluble in water and insoluble in alcohol. The pH of
a 1 in 100 solution is between 11.5 and 12.0.1,6
Methylcellulose (Methocel) is a practically odorless and tasteless,
white to yellowish-white granule or powder. It is hygroscopic and is
practically insoluble in acetone, ethanol, saturated salt solutions, and
hot water. In cold water, methylcellulose swells and disperses to form a
viscous, colloidal dispersion.7
Sulfuric acid (H2SO4, MW 98.08) contains, by weight, not less than 95.0% and not more than 98.0% of H2SO4. It is miscible with water and with alcohol with the generation of a lot of heat.8
REFERENCES
1. U.S. Pharmacopeia 35/National Formulary 30. Rockville, MD: US Pharmacopeial Convention, Inc; 2012:344-386,1103,1131,1145,1957-1958.
2. Allen LV Jr. Standard operating procedure for performing physical quality assessment of oral and topical liquids. IJPC. 1999;3:146-147.
3. Quinn ME. Benzethonium chloride. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:61-63.
4. Alvarez-Nunez FA, Medina C. Glycerin. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:283-286.
5. Goggin PL. Sodium cyclamate. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:643-645.
6. Kearney AS. Sodium phosphate, dibasic. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:656-658.
7. Allen LV Jr, Luner PE. Methylcellulose. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:438-441.
8. Amidon GE. Sulfuric acid. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:719-720.
To comment on this article, contact rdavidson@uspharmacist.com.
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