Amlodipine 1 mg/mL in Oral Mix Suspension Vehicle

US Pharm. 2022;47(2):56-57.

Method of Preparation: Calculate the required quantity of each ingredient for the total amount to be prepared. Accurately weigh or measure each ingredient. Pulverize the tablets to a very fine powder. Add 5 mL of the Oral Mix flavored suspending vehicle and mix to form a smooth paste. Incrementally, add 50 mL of the Oral Mix flavored suspending vehicle, mixing well after each addition. Transfer to an appropriate dispensing container or dosing syringes as described in the Stability section; package and label. Note: Stability data are provided for two different types of dispensing containers.

Use: Amlodipine is used as an antihypertensive and antianginal.

Packaging: Package in tight, light-resistant amber glass containers or in PreciseDose Dispenser amber syringes.

Labeling: Keep out of reach of children. Discard after ____ [time period]. Shake or mix well. Do not freeze. Protect from light. Store as directed.

Stability: When packaged in amber glass bottles, a beyond-use date of 90 days at refrigerated temperature or 60 days at room temperature may be used for this preparation when compounded with the exact ingredients listed and according to the procedures provided. When packaged in PreciseDose Dispenser amber syringes, a beyond-use date of 90 days at refrigerated temperature or 45 days at room temperature may be used when prepared with the exact ingredients listed and according to the procedures provided based on stability studies performed by Medisca.^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), and preservative-effectiveness test.^3,4 Note: The vehicle in this formula contains preservatives and is slightly acidic.

Discussion: Amlodipine besylate (Norvasc, C₂₀H₂₅ClN₂O₅.C₆H₆O₃S, MW 567.05) occurs as a white or almost-white powder that is sparingly soluble in alcohol and in water. It is a 1,4-dihydropyridine derivative calcium channel blocker with an intrinsically long duration of action. Amlodipine is used alone or in combination with other classes of antihypertensive agents in the management of hypertension, and it also is used to treat angina. The agent is well absorbed orally, with an onset of action of 20 to 50 minutes and a duration of effect of 24 hours. Grapefruit juice can modestly increase amlodipine blood levels. The dosage in children aged 6 to 17 years is 2.5 mg to 5 mg once daily. In adults, treatment should be initiated at 5 mg once daily and titrated in 2.5-mg increments to a maximum of 10 mg daily. In elderly patients, treatment is initiated at the low end of the dosing range, as some individuals exhibit decreased clearance of amlodipine. Small dose adjustments are easily accommodated with this liquid formulation and with dosing syringes. The drug may be taken without regard to meals.⁵

Norvasc is formulated as white tablets equivalent to 2.5 mg, 5 mg, and 10 mg of amlodipine for oral administration. In addition to the active ingredient (amlodipine besylate), each tablet contains microcrystalline cellulose, dibasic calcium phosphate anhydrous, sodium starch glycolate, and magnesium stearate.^1,5

Medisca’s Oral Mix SF cherry-flavored suspending vehicle was formulated for convenience and is used to simplify the preparation of extemporaneous dosage forms when dietary restrictions are a concern. This one-step vehicle combines the suspending properties of Medisca’s Oral Suspend and the flavoring agents of its Oral Syrup SF (sugar-free). Oral Mix SF is formulated with a slightly acidic pH and with a balance of preservatives and buffering agents to help minimize common degradation. When mixed with medicated powders or crushed tablets, the final compounded products form physically stable suspensions. Oral Mix SF is free of alcohol and dyes.⁶ Other related Oral Mix products for compounding oral liquid preparations include Oral Mix and Oral Mix Dry Alka SF.^7,8

REFERENCES

1. U.S. Pharmacopeia/National Formulary [current revision]. Rockville, MD: U.S. Pharmacopeial Convention, Inc; January 2022.
2. Medisca. Amlodipine besylate stability studies. www.medisca.com/Pages/ProductSearch.aspx?Search=AMLODIPINE+BESYLATE%2c+USP&Exact=1. Accessed January 10, 2022.
3. Allen LV Jr. Summary of quality-control testing for sterile and nonsterile compounded preparations, part 1: physical and chemical testing. IJPC. 2019;23(3):211-216.
4. Allen LV Jr. Summary of quality-control testing for sterile and nonsterile compounded preparations, part 2: microbiological testing. IJPC. 2019;23(4):299-303.
5. Norvasc. RxList. www.rxlist.com/norvasc-drug.htm. Accessed January 7, 2022.
6. Medisca. Oral Mix SF (sugar-free flavored suspending vehicle) product information. www.medisca.com/Pages/ProductDetails.aspx?StockCode=2600&C=B&C2=110. Accessed January 10, 2022.
7. Medisca. Oral Mix (flavored suspending vehicle) product information. www.medisca.com/Pages/ProductDetails.aspx?StockCode=2512&C=B&C2=110. Accessed January 10, 2022.
8. Medisca. Oral Mix Dry Alka SF (oral vehicle). www.medisca.com.au/Pages/ProductDetails.aspx?StockCode=3078&C=B&C2=110. Accessed January 10, 2022.

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