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Amlodipine 1 mg/mL Oral Liquid

Loyd V. Allen, Jr., PhD
Professor Emeritus
College of Pharmacy, University of Oklahoma
Oklahoma City, Oklahoma



2/19/2014

 US Pharm. 2014;39(2):55-56.


Method of Preparation: Calculate the quantity of each ingredient for the amount to be prepared. Accurately weigh or measure each ingredient. Pulverize the required number of tablets to a fine powder, or use the powder. Add a portion of the Ora-Plus and mix until a smooth paste is obtained. Add the remainder of the Ora-Plus geometrically and mix well. Add the Ora-Sweet in portions to the final volume and mix until uniform. Package and label.

Note: An alternative vehicle consisting of a 1:1 mixture of syrup NF and 1% methylcellulose solution may be used if the combination of Ora-Plus and Ora-Sweet is not suitable. The 1% methylcellulose solution is prepared by mixing methylcellulose 4,000 cps (1 g), methylparaben (20 mg), propylparaben (10 mg), and sufficient hot purified water to 100 mL and allowing the mixture to cool.1

Use: This preparation has been used in the treatment of pediatric patients with hypertension.

Packaging: Package in tight, light-resistant containers.

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

Stability: A beyond-use date of up to 91 days at refrigerated temperature or 56 days at room temperature for the Ora-Plus/Ora-Sweet preparation and up to 56 days at refrigerated or room temperature for the syrup NF/1% methylcellulose solution preparation has been reported.1-4

Quality Control: Quality-control assessment can include weight/volume, pH (approximately 4.6 for the “Ora” preparation and 6.5 to 7.0 for the syrup preparation), specific gravity, active drug assay, color, rheologic properties/pourability, physical observation, and physical stability (discoloration, foreign materials, gas formation, mold growth).5

Discussion: Amlodipine besylate (Norvasc, C20H25ClN2O5.C6H6O3S, MW 567.05) is a calcium channel blocker that is used as an antihypertensive agent. This liquid dosage form is suitable for pediatric patients and for other patients who cannot swallow a solid oral dosage form. Amlodipine besylate occurs as a white or almost-white powder that is slightly soluble in water and sparingly soluble in alcohol.2

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.6

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. 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

Syrup (simple syrup) is a clear, sweet vehicle used as a sweetening agent and as the base for many flavored and medicated syrups. It contains 85% w/v sucrose in water and has a specific gravity of not less than 1.30. Syrup is generally self-preserving as long as the sucrose concentration is maintained at a sufficiently high level. It should be stored in tight containers, preferably in a cool place.2

Methylcellulose (Methocel) is a practically odorless and tasteless, white to yellowish-white granule or powder that is widely used in oral and topical formulations. It is hygroscopic and is practically insoluble in acetone, ethanol, saturated salt solutions, and hot water, but it is soluble in glacial acetic acid. In cold water, methylcellulose swells and disperses to form a viscous, colloidal dispersion.8

REFERENCES

1. Nahata MC, Hipple TF. Stability of amlodipine besylate in two liquid dosage forms. J Am Pharm Assoc (Wash). 1999;39:375-377.
2. U.S. Pharmacopeia 36/National Formulary 31. Rockville, MD: U.S. Pharmacopeial Convention, Inc; 2013:335-398,1242,2262.
3. Nahata MC, Hipple TF. Pediatric Drug Formulations. 4th ed. Cincinnati, OH: Harvey Whitney Books; 2000.
4. Trissel LA. Trissel’s Stability of Compounded Formulations. 5th ed. Washington, DC: American Pharmacists Association; 2012:34.
5. Allen LV Jr. Standard operating procedure for performing physical quality assessment of oral and topical liquids. IJPC. 1999;3:146-147.
6. Ora-Plus product information. Minneapolis, MN: Paddock Laboratories, Inc; 2010.
7. Ora-Sweet product information. Minneapolis, MN: Paddock Laboratories, Inc; 2010.
8. Allen LV Jr, Luner PE. Methylcellulose. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. Washington, DC: American Pharmaceutical Association; 2009:438-441.

To comment on this article, contact rdavidson@uspharmacist.com.

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