Pimozide

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

C₂₈H₂₉F₂N₃O 461.55

2H-Benzimidazol-2-one, 1-[1-[4,4-bis(4-fluorophenyl)butyl]-4-piperidinyl]-1,3-dihydro-;

1-[1-[4,4-Bis(p-fluorophenyl)butyl]-4-piperidyl]-2-benzimidazolinone CAS RN^®: 2062-78-4; UNII: 1HIZ4DL86F.

1 DEFINITION

Pimozide contains NLT 98.0% and NMT 102.0% of pimozide (C₂₈H₂₉F₂N₃O), calculated on the dried basis.

2 IDENTIFICATION

Change to read:

A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197A or 197K. (CN 1-May-2020)

B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

3.1 PROCEDURE

Solution A: 2.5 g/L of ammonium acetate and 8.5 g/L of tetrabutylammonium hydrogen sulfate in water

Solution B: Acetonitrile

Mobile phase: See Table 1.

Table 1

System suitability solution: 0.05 mg/mL of USP Pimozide RS and 0.02 mg/mL of USP Mebendazole RS in methanol

Standard solution: 1 mg/mL of USP Pimozide RS in methanol

Sample solution: 1 mg/mL of Pimozide in methanol. [NOTE-Sonication may be needed to dissolve the sample.]

3.2 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 280 nm

Column: 4.6-mm x 10-cm; 3-µm packing L1

Flow rate: 2 mL/min

Injection volume: 10 µL

3.3 System suitability

Samples: System suitability solution and Standard solution

[NOTE-See Table 2 for the relative retention times.]

Suitability requirements

Resolution: NLT 5.0 between pimozide and mebendazole, System suitability solution

Tailing factor: NMT 2.0, Standard solution

Relative standard deviation: NMT 0.73%, Standard solution

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of pimozide (C₂₈H₂₉F₂N₃O) in the portion of Pimozide taken:

Result = (r_U/r_S) x (C_S/C_U) x 100

r_U = peak response of pimozide from the Sample solution

r_S = peak response of pimozide from the Standard solution

C_S = concentration of USP Pimozide RS in the Standard solution (mg/mL)

C_U = concentration of Pimozide in the Sample solution (mg/mL)

Acceptance criteria: 98.0%-102.0% on the dried basis

4 IMPURITIES

4.1 RESIDUE ON IGNITION (281)

NMT 0.2%

4.2 ORGANIC IMPURITIES

Solution A, Solution B, Mobile phase, System suitability solution, and Chromatographic system: Proceed as directed in the Assay.

Standard solution: 0.05 mg/mL of USP Pimozide RS in methanol

Sample solution: 10 mg/mL of Pimozide in methanol. [NOTE-Sonication may be needed to dissolve the sample.]

System suitability

Samples: System suitability solution and Standard solution

[NOTE-See Table 2 for the relative retention times.]

Suitability requirements

Resolution: NLT 5.0 between pimozide and mebendazole, System suitability solution

Tailing factor: NMT 2.0, Standard solution

Relative standard deviation: NMT 2.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity in the portion of Pimozide taken:

Result = (r_U/r_S) x (C_S/C_U) x 100

r_U = peak response of each impurity from the Sample solution

r_S = peak response of pimozide from the Standard solution

C_S = concentration of USP Pimozide RS in the Standard solution (mg/mL)

C_U = concentration of Pimozide in the Sample solution (mg/mL)

Acceptance criteria: See Table 2.

Table 2

^a 1-(Piperidin-4-yl)benzimidazolin-2-one.

^b Included for system suitability purposes only. Not a process impurity or degradation product.

^c 1-{1-[4-(4-Fluorophenyl)-4-phenylbutyl]piperidin-4-yl}benzimidazolin-2-one.

^d 1-{1-[4-(2-Fluorophenyl)-4-(4-fluorophenyl)butyl]piperidin-4-yl}-1H-benzimidazol-2-one.

^e 1-{1-[4,4-Bis(4-fluorophenyl)butyl]-1,2,3,6-tetrahydropyridin-4-yl}benzimidazolin-2-one.

^f 1-{1-[4,4-Bis(4-fluorophenyl)but-3-en-1-yl]piperidin-4-yl}benzimidazolin-2-one.

^g 1-[4,4-Bis(4-fluorophenyl)butyl)-4-(2-oxobenzimidazol-1-yl)piperidine 1-oxide.

5 SPECIFIC TESTS

LOSS ON DRYING (731)

Analysis: Dry at 105° to a constant weight.

Acceptance criteria: NMT 0.5%

6 ADDITIONAL REQUIREMENTS

6.1 PACKAGING AND STORAGE

Preserve in tight, light-resistant containers.

6.2 USP REFERENCE STANDARDS (11)

USP Mebendazole RS

USP Pimozide RS