US Pharm. 2024;49(10):59-60.


Method of Preparation: Calculate the amount of each ingredient required for the total amount to be prepared. After removing the trademark imprint from the tablets with a paper towel dampened with Alcohol USP, let the tablets air-dry for a few minutes. Using a mortar and pestle, triturate the tablets to a fine powder. Add a small amount of sterile water and levigate the powder until a uniform paste results. Geometrically incorporate portions of the vehicle and cherry syrup, and mix completely. Transfer the liquid to a calibrated bottle. Add a small amount of cherry syrup to the mortar to rinse it of any drug residue; then add contents to the calibrated bottle. Add additional vehicle to bring the final volume to 120 mL. Shake well until the powder is uniformly suspended.1

Use: Chloroquine phosphate oral suspension has been used to prevent and treat malaria and to manage amebiasis. It also may be used in treating certain inflammatory conditions.

Packaging: Package in a tight, light-resistant container. Store under refrigeration.

Labeling: Keep out of reach of children. Shake well. Discard after ____ [time period].

Stability: The USP default beyond-use date for nonpreserved aqueous oral liquids is 14 days when stored in a refrigerator.2 However, based on additional stability studies on a similar strength (15 mg/mL) of this extemporaneous oral suspension, this preparation is stable for up to 60 days when stored at 5°C to 25°C.3

Quality Control: Weight/volume, pH, specific gravity, active drug assay, color, rheologic properties/pourability, physical observation, and physical stability (discoloration, foreign materials, gas formation, mold growth) are all examples of quality-control assessments.4

Discussion: Chloroquine phosphate (C18H26ClN3 • 2H3PO4, MW 515.87) is a white, odorless, bitter, crystalline substance that is freely soluble in water.5 It is rapidly absorbed from the gastrointestinal tract, with only a small amount found in the stool. Used primarily as an antimalarial, chloroquine phosphate inhibits the growth of parasites in the body by preventing their entry into red blood cells, thereby halting disease progression. In amebiasis, it directly kills parasites in the intestines. The drug is also employed to reduce pain and inflammation in conditions such as rheumatoid arthritis, although its exact mechanism of action, particularly its plasmodicidal effect, is not fully understood. Some of its effects may result from its interaction with DNA or its inhibition of certain enzymes.

Chloroquine phosphate is contraindicated in patients with retinal or visual-field changes and in patients with known hypersensitivity to 4-aminoquinoline compounds. Caution is advised in patients with glucose-6-phosphate dehydrogenase deficiency. Common side effects include nausea, vomiting, diarrhea, and headache. To minimize gastrointestinal discomfort, it is recommended to take chloroquine phosphate with food or milk.5

Sterile or purified water is an essential solvent used in pharmaceutical preparations. Purified water is obtained through processes such as distillation, reverse osmosis, or ion exchange. It is chemically stable across physical states and miscible with most polar solvents, making it ideal for compounding solutions, suspensions, and syrups. Sterile water, which is used for injections or ophthalmic preparations, undergoes stringent sterilization to ensure that it is free from microorganisms and pyrogens, enhancing patient safety in IV and IM applications.6

Cherry syrup is a vehicle commonly used to mask the unpleasant taste of drugs such as chloroquine. The syrup is a sucrose-based solution often enhanced with natural or artificial cherry flavoring to enhance palatability. Cherry syrup also contains preservatives such as sodium benzoate to maintain stability and prevent microbial growth. Because of its versatility, cherry syrup is frequently used in compounding to aid in the administration of bitter drugs, particularly in pediatric patients and other patients who cannot tolerate unpleasant-tasting medications.7

REFERENCES

1. Nahata MC, Pai VB, Hipple TF. Pediatric Drug Formulations. 5th ed. Cincinnati, OH: Harvey Whitney Books; 2004.
2. U.S. Pharmacopeia/National Formulary [current revision]. Rockville, MD: U.S. Pharmacopeial Convention, Inc; September 2022.
3. Allen LV Jr, Erickson MA III. Stability of alprazolam, chloroquine phosphate, cisapride, enalapril maleate, and hydralazine hydrochloride in extemporaneously compounded oral liquids. Am J Health Syst Pharm. 1998;55(18):1915-1920.
4. Allen LV Jr. Standard operating procedure for performing physical quality assessment of oral and topical liquids. IJPC. 1999;3:146-147.
5. Chloroquine phosphate tablets. Eatontown, NJ: West-Ward Pharmaceutical Corp; October 2009.
6. Dubash D, Shah U. Water. In: Sheskey PJ, Cook WG, Cable CG, eds. Handbook of Pharmaceutical Excipients. 8th ed. Washington, DC: American Pharmaceutical Association; 2017:1012-1016.
7. Cutaia K, Chablani L, Zhao F. Basics of compounding: vehicles for compounded oral liquid medications: a review. Int J Pharm Compd. 2018;22(6):480-489.

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