Famotidine 8 mg/mL Oral Liquid

US Pharm. 2016;41(12):42-43.

Method of Preparation: Calculate the quantity of each ingredient for the amount to be prepared. Accurately weigh or measure each ingredient or obtain the required number of famotidine 40 mg tablets. Pulverize the tablets, if used, and/or mix the powder with a few mL of purified water to form a smooth paste. Geometrically, add the Ora-Plus:Ora-Sweet (1:1) mixture to final volume, mixing between each addition. Package and label. Note: Ora-Blend could be used in place of the Ora-Plus:Ora-Sweet (1:1) mixture.

Use: Famotidine oral liquid is used in the treatment of heartburn in patients who cannot swallow the tablets or cannot take the commercial product.

Packaging: Package in tight, light-resistant containers.

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

Stability: A beyond-use date of up to 95 days has been used for this preparation.^1,2

Quality Control: Quality-control assessment may include weight/volume, pH, specific gravity, active drug assay, color, rheologic properties/pourability, physical observation, and physical stability (discoloration, foreign materials, gas formation, and mold growth).³

Discussion: Famotidine is listed as being used for the treatment of duodenal ulcers and gastric ulcers, for controlling gastric pH in critically ill patients, for symptomatic relief of gastritis and gastroesophageal reflux, and for the treatment of active benign ulcers and pathologic hypersecretory conditions. The nonprescription product is labeled for the relief of heartburn, acid indigestion, and sour stomach.⁴

Famotidine (Pepcid, C₈H₁₅N₇O₂S₃, MW 337.45) occurs as a white to yellowish-white or pale yellow, odorless, crystalline powder with a bitter taste. It is slightly soluble in water and practically insoluble in ethanol. Famotidine has a melting range of about 163°C to 164°C.¹ In a separate stability study, famotidine alone in aqueous buffer solutions exhibited identical stability at pH 4 and pH 6.⁵

In the event that tablets are used in compounding this preparation, each tablet contains famotidine 20 mg or 40 mg and the following inactive ingredients: methylparaben hydroxypropyl cellulose, iron oxides, magnesium stearate, microcrystalline cellulose, corn starch, talc, titanium dioxide, and carnauba wax. The presence of hydroxypropyl cellulose and hypromellose (hydroxypropyl methylcellulose) may result in a slightly thicker preparation than when the bulk famotidine powder is used.⁶

Ora-Plus is an oral suspending vehicle that accepts dilution of up to 50% or more with water, flavoring agents, or syrups while still retaining its suspending properties. It has a pH of approximately 4.2 and an osmolality of about 230 mOsm/kg. Ora-Plus is a thixotropic vehicle with a viscosity of approximately 1,000 cps at 25°C. It contains purified water, microcrystalline cellulose, sodium carboxymethylcellulose, xanthan gum, carrageenan, sodium phosphate, and citric acid as buffering agents; simethicone as an antifoaming agent; and potassium sorbate and methylparaben as preservatives.⁷

Ora-Sweet syrup vehicle is a flavoring vehicle for oral extemporaneous preparations. It is flavored with a citrus-berry flavor blend and contains glycerin and sorbitol to prevent cap lock, a problem associated with many syrups. Ora-Sweet is buffered to a pH of approximately 4.2 and has an osmolality of about 3,240 mOsm/kg. Ora-Sweet contains purified water, sucrose, glycerin, sorbitol (5%), flavoring, sodium phosphate, and citric acid as buffering agents and potassium sorbate and methylparaben as preservatives.⁸

Ora-Blend is a sweetened oral suspending vehicle used to simplify the process involved in the extemporaneous compounding of oral suspensions. It is an aqueous-based, sweetened vehicle consisting of a synergistic blend of suspending agents that have a high degree of colloidal activity. Ora-Blend is buffered to a slightly acidic pH of approximately 4.2, and it has a viscosity of approximately 700 cps at 25°C and an osmolality of 2,107 mOsm/kg. Ora-Blend occurs as an opaque, pinkish liquid with a sweet citrus-berry flavor. It contains purified water, sucrose, glycerin, sorbitol, flavoring, microcrystalline cellulose, carboxymethylcellulose sodium, xanthan gum, carrageenan, citric acid, and sodium phosphate as buffers; simethicone as an antifoaming agent; and methylparaben and potassium sorbate as preservatives.⁹

REFERENCES

1. U.S. Pharmacopeia/National Formulary [current revision]. Rockville, MD: U.S. Pharmacopeial Convention, Inc; November 2016.
2. Dentinger PJ, Swenson CF, Anaizi NH. Stability of famotidine in an extemporaneously compounded oral liquid. Am J Health Syst Pharm. 2000;57:1340-1342.
3. Allen LV Jr. Standard operating procedure for performing physical quality assessment of oral and topical liquids. IJPC. 1999;3:146-147.
4. Lacy CF, Armstrong LL, Goldman MP, Lance LA, eds. Drug Information Handbook. 13th ed. Hudson, OH: Lexi-Comp; 2005:605-606.
5. Wu YQ, Fassihi R. Stability of metronidazole, tetracycline HCl and famotidine alone and in combination. Int J Pharm. 2005;290:1-13.
6. Pepcid. www.rxlist.com/pepcid-drug.htm. Accessed November 8, 2016.
7. Ora-Plus product information. Allegan, MI: Perrigo; 2014.
8. Ora-Sweet product information. Allegan, MI: Perrigo; 2014.
9. Ora-Blend product information. Allegan, MI: Perrigo; 2014.

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