Mirtazapine Compounded Oral Suspension, Veterinary

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

1 DEFINITION

Mirtazapine Compounded Oral Suspension, Veterinary contains NLT 90.0% and NMT 110.0% of the labeled amount of mirtazapine (C₁₇H₁₉N₃).

Prepare Mirtazapine Compounded Oral Suspension, Veterinary 10 mg/mL as follows (see Pharmaceutical Compounding—Nonsterile

Preparations 〈795〉).

^a Mirtazapine 30-mg tablets, Mylan Pharmaceuticals, Inc., Morgantown, WV.

^b Perrigo, Allegan, MI.

Place the Mirtazapine tablets in a suitable container and triturate to a fine powder. Add a small amount of Vehicle and mix well to form a smooth paste. Add a sufficient amount of Vehicle to make the contents pourable. Transfer contents stepwise and quantitatively to a calibrated container using the remainder of the Vehicle. Add sufficient Vehicle to bring to final volume. Mix well.

2 ASSAY

PROCEDURE

Mobile phase: Add 23.5 mL of 25% tetramethylammonium hydroxide solution to 626.5 mL of water. Adjust with phosphoric acid to a pH of 7.4. Add 150 mL of acetonitrile, 125 mL of methanol, and 75 mL of tetrahydrofuran.

Diluent: Acetonitrile and water (50:50)

Standard solution: 0.5 mg/mL of USP Mirtazapine RS in Diluent

Sample solution: Transfer 0.5 mL of Oral Suspension, Veterinary to a 10-mL volumetric flask, and add Diluent to volume. Pass through a filter of 0.22-um pore size.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 295 nm

Column: 4.6-mm x 25-cm; 5-µm packing L1

Column temperature: 60°

Flow rate: 1.5 mL/min

Injection volume: 10 µL

System suitability

Sample: Standard solution

[NOTE-The retention time for mirtazapine is about 25.4 min.]

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of mirtazapine (C₁₇H₁₉N₃) in the portion of Oral Suspension, Veterinary taken:

Result = (r_u /r_s ) × (C_s /C_u ) × 100

r_u = peak response of mirtazapine from the Sample solution

r_s = peak response of mirtazapine from the Standard solution

C_s = concentration of USP Mirtazapine RS in the Standard solution (mg/mL)

C_u = nominal concentration of mirtazapine in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0%

3 SPECIFIC TESTS

PH (791): 5.6-6.6

4 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Package in tight, light-resistant containers. Store at controlled room temperature or in a refrigerator.

BEYOND-USE DATE: NMT 90 days after the date on which it was compounded when stored at controlled room temperature or in a refrigerator.

LABELING: Label it to state that it is to be well shaken before use, and to state the Beyond-Use Date. Label it to state that it is for veterinary use only.

USP REFERENCE STANDARDS (11).

USP Mirtazapine RS