Verapamil Hydrochloride 50 mg/mL Oral Liquid

US Pharm. 2016;41(2):46-47.

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 verapamil hydrochloride tablets. Place the powder or tablets in a mortar and pulverize to a fine powder (if tablets are used). Slowly add the Ora-Plus with thorough mixing. Incorporate sufficient Ora-Sweet or Ora-Sweet SF to final volume and mix well. Package and label.

Use: Verapamil hydrochloride is a calcium channel blocker used as an antianginal, antiarrhythmic, and antihypertensive.

Packaging: Package in tight, light-resistant containers.

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

Stability: When prepared as above, a beyond-use date of up to 6 months may be used for this preparation.^1,2

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

Discussion: Verapamil hydrochloride oral liquid is used in a broad age range of patients. Many of these patients cannot swallow the intact tablets and therefore require a formulation such as that presented here. The concentration of the drug in this preparation may be altered to meet the needs of the patient. A wide variety of oral vehicles may be used for this preparation, from simple syrup to the vehicles listed above, as well as many other commercial types. It is important to confirm the actual formulation/ingredients of the vehicles when assigning a beyond-use date to the preparation.

Verapamil hydrochloride (Calan, Covera, Isoptin, Verelan, C₂₇H₃₈N₂O₄.HCl, MW 491.06) occurs as a white or practically white, crystalline powder that is practically odorless, has a bitter taste, and melts at about 140°C. It is soluble in water (1 g in about 15 mL), sparingly soluble in alcohol (1 g in 25 mL), and soluble in most organic solvents. The pH of a 7% w/w aqueous solution is about 4.2. Verapamil hydrochloride should be stored at controlled room temperature and protected from light and freezing. It is incompatible with alkaline solutions. Verapamil hydrochloride is a calcium antagonist or slow-channel inhibitor, an antianginal, and a cardiac depressant (antiarrhythmic). Verapamil hydrochloride is reported to be stable when refluxed under neutral, acidic, and basic aqueous conditions with an optimum pH range for stability of 3.2 to 5.6.^1,4,5

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. Ora-Plus has a pH of approximately 4.2, and it has an osmolality of about 230 mOsm/kg. Ora-Plus is a thixotropic vehicle with a viscosity of approximately 1,000 cps at 25°C. Ora-Plus 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.⁶

Ora-Sweet is a flavoring vehicle for oral extemporaneous preparations. It is a syrup 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. It contains purified water, sucrose, glycerin, sorbitol (5%), flavoring, sodium phosphate, and citric acid as buffering agents and potassium sorbate and methylparaben as preservatives.⁷

Ora-Sweet SF is a flavoring vehicle for oral extemporaneous preparations. It is a sugar-free, alcohol-free syrup flavored with a citrus-berry flavor blend. Ora-Sweet SF is buffered to a pH of approximately 4.2 and it may be used alone or in combination with other vehicles. It will tolerate a dilution to 50% with dissolved actives in water or suspending agents while still retaining an acceptable taste. Ora-Sweet SF has an osmolality of 2,150 mOsm/kg. It contains water, sodium saccharin, xanthan gum, glycerin, sorbitol, citric acid, and sodium citrate as buffers; methylparaben, propylparaben, and potassium sorbate as preservatives; and flavoring agents.⁸

REFERENCES

1. U.S. Pharmacopeia/National Formulary [current revision]. Rockville, MD: U.S. Pharmacopeial Convention, Inc; January 2016.
2. Allen LV Jr, Erickson MA III. Stability of labetalol hydrochloride, metoprolol tartrate, verapamil hydrochloride, and spironolactone with hydrochlorothiazide in extemporaneously compounded oral liquids. Am J Health Syst Pharm. 1996;53:2304-2309.
3. Allen LV Jr. Standard operating procedure for performing physical quality assessment of oral and topical liquids. IJPC. 1999;3:146-147.
4. Allen LV Jr, ed. Remington: The Science and Practice of Pharmacy. 22nd ed. London, England: Pharmaceutical Press; 2012:1818-1819.
5. Chang ZL. Verapamil. In: Florey K, ed. Analytical Profiles of Drug Substances. Vol 17. New York, NY: Academic Press; 1988:643-674.
6. Ora-Plus product information. Allegan, MI: Perrigo; 2014.
7. Ora-Sweet product information. Allegan, MI: Perrigo; 2014.
8. Ora-Sweet SF product information. Allegan, MI: Perrigo; 2014.

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