Potassium Citrate 100 mg/mL and Methscopolamine Hydrobromide 0.5 mg/mL Solution

US Pharm. 2010;35(8):64-65.

Method of Preparation: Calculate the quantity of each ingredient for the amount to be prepared. Accurately weigh or measure each ingredient. Combine the alcohol, orange oil, methylparaben, and propylparaben. Separately, dissolve the potassium citrate in about 20 mL purified water. Add the glycerin, syrup, and sodium carboxymethylcellulose (CMC) solution, followed by the methscopolamine hydrobromide; mix well. Combine the two separate solutions. Add sufficient purified water to volume; mix well. Package and label.

Use: This preparation has been used to alkalinize the urine and relieve bladder spasms.

Packaging: Package in tight, light-resistant containers.

Labeling: Shake well before taking. Keep out of the reach of children. Discard after ____ [time period]. Store in a refrigerator.

Stability: A beyond-use date of 14 days when stored in a refrigerator may be used.¹

Quality Control: Quality-control assessment can include weight/volume, pH, specific gravity (SG), active drug assay, color, clarity, physical observation, and physical stability (discoloration, foreign materials, gas formation, mold growth).²

Discussion: This compound is an update of a formulation previously known as Potassium Citrate and Hyoscyamus Tincture Mixture, which was also called Alkaline Bladder Mixture. The current formulation is much more predictable and uniform for dosing purposes.

Potassium citrate (tripotassium citrate monohydrate; C₆H₅K₃O₇.H₂O, MW 324.41) occurs as transparent crystals or as a white, granular powder with a cooling, salty taste. It is deliquescent in moist air, and its solutions are alkaline to litmus. One g dissolves in about 1 mL water, and it is almost insoluble in alcohol. It is used as a systemic and urinary alkalinizer, as well as for the effects of the potassium ion.³

Methscopolamine hydrobromide (hyoscine methobromide, scopolamine methylbromide, C₁₈H₂₄BrNO₄, MW 398.3) occurs as white crystals or as a white, odorless, crystalline powder. It is freely soluble in water and slightly soluble in alcohol. It should be stored in airtight containers and protected from light.⁴

Glycerin (glycerol, 1,2,3-propane triol) occurs as a clear, colorless, odorless, viscous, hygroscopic liquid with a sweet taste. It has an SG of about 1.25. It is miscible with water and 95% ethanol; it is practically insoluble in oils and slightly soluble in acetone.⁵

Syrup (simple syrup) is a clear, sweet vehicle used as a sweetening agent and as a base for many flavored and medicated syrups. It contains 85% w/v sucrose in water and has an SG of not less than 1.30.¹

Sodium CMC (carmellose sodium) occurs as a white to cream-colored, hygroscopic powder or granules. The pH of a 1% aqueous solution is between 6.5 and 8.5.⁴

Alcohol (ethyl alcohol, ethanol, grain alcohol, C₂H₅OH, MW 46.07) is a clear, colorless, mobile and volatile liquid with a slight, characteristic odor and a burning taste. Alcohol USP refers to 95% ethanol, and dehydrated alcohol refers to 99.5% alcohol. Its SG is between 0.812 and 0.816. It is miscible with glycerin and water.⁶

Orange oil is the volatile oil obtained by expression from the fresh peel of the ripe fruit of Citrus sinensis (Linné) Osbeck (fam Rutaceae). It is used as a flavoring agent.⁷

Methylparaben (methyl hydroxybenzoate, methyl parahydroxybenzoate, C₈H₈O₃) is available as colorless crystals or as a white, crystalline powder that is odorless or almost odorless and has a slight burning taste. It is an antimicrobial preservative in which 1 g is soluble in 400 mL water, 3 mL 95% ethanol, and 60 mL glycerin.⁸

Propylparaben (propyl hydroxybenzoate, propyl parahydroxybenzoate, C₁₀H₁₂O₃) is available as a white, crystalline, odorless and tasteless powder. It is an antimicrobial preservative  in which 1 g is soluble in 2,500 mL water and 1.1 mL ethanol.⁹

REFERENCES

1. USP Pharmacists' Pharmacopeia. 2nd ed. Rockville, MD: US Pharmacopeial Convention, Inc; 2008:388.
2. Allen LV Jr. Standard operating procedure for performing physical quality assessment of oral and topical liquids. IJPC. 1999;3:146-147.
3. Harvey SC. Blood, fluids, electrolytes, and hematologic drugs. In: Osol A, Chase GD, Gennaro AR, et al, eds. Remington's Pharmaceutical Sciences. 16th ed. Easton, PA: Mack; 1980:777.
4. Reynolds JEF, ed. Martindale: The Extra Pharmacopoeia. 30th ed. London, England: Pharmaceutical Press; 1993:426,1415.
5. 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.
6. Quinn ME. Alcohol. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:17-19.
7. Reilly WJ Jr. Pharmaceutical necessities. In: Troy DB. Remington: The Science and Practice of Pharmacy. 21st ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005:1066.
8. Haley S. Methylparaben. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:441-445.
9. Haley S. Propylparaben. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:596-598.

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