Pindolol Tablets

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

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

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1 DEFINITION

Pindolol Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of pindolol (C₁₄H₂₀N₂O₂).

2 IDENTIFICATION

A. The UV spectrum of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

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

3 ASSAY

Change to read:

3.1 PROCEDURE

Solution A: 6 mg/mL of ammonium carbonate in water

Mobile phase: Acetonitrile, methanol, and Solution A (19:19:2)

Standard solution: 0.2 mg/mL of USP Pindolol RS in Mobile phase

System suitability solution: 0.2 mg/mL of USP Nortriptyline Hydrochloride RS in Standard solution

Sample solution: Transfer a portion of the powdered Tablets (NLT 20 Tablets), nominally equivalent to 20 mg of pindolol, to a 100-mL volumetric flask, add 4 mL of water, and sonicate for 2 min, with occasional shaking to disperse the powder. Add 30 mL of Mobile phase, sonicate for 15 min, and allow to cool. Dilute with Mobile phase to volume, and filter. Use the clear filtrate as the Sample solution.

3.2 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 254 nm. For Identification A, use a diode array detector in the range of 200-400 nm.

Column: 4.6-mm x 25-cm; 5-µm packing L16

Flow rate: 3 mL/min

Injection volume: 10 µL

Run time: NLT 2 times the retention time of the nortriptyline (ERR 1-Jan-2021) peak

3.3 System suitability

Samples: Standard solution and System suitability solution

[NOTE-The relative retention times for pindolol and nortriptyline are 0.6 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 1.5 between pindolol and nortriptyline, System suitability solution

Relative standard deviation: NMT 2.0% of pindolol, Standard solution

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of pindolol (C₁₄H₂₀N₂O₂) in the portion of Tablets taken:

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

r_U = peak response of pindolol from the Sample solution

r_S = peak response of pindolol from the Standard solution

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

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

Acceptance criteria: 90.0%-110.0%

4 PERFORMANCE TESTS

4.1 DISSOLUTION (711)

Medium: 0.1 N hydrochloric acid; 500 mL

Apparatus 2: 50 rpm

Time: 15 min

Mobile phase and Chromatographic system: Proceed as directed in the Assay.

Standard stock solution: 0.002J mg/mL of USP Pindolol RS in Medium. [NOTE-J is the labeled quantity, in milligrams, of pindolol in each Tablet.]

Standard solution: Mobile phase and Standard stock solution (1:1)

System suitability solution: 0.005 mg/mL of USP Nortriptyline Hydrochloride RS in Standard solution

Sample solution: Filter a portion of the solution under test. Mix equal volumes of the filtrate and of Mobile phase.

Analysis:

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of pindolol (C₁₄H₂₀N₂O₂) dissolved:

Result = (r_U/r_S) x C_S x V x D x (100/L)

r_U = peak response of pindolol from the Sample solution

r_S = peak response of pindolol from the Standard solution

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

V = volume of the Medium, 500 mL

L = label claim (mg/Tablet)

D = dilution factor for the Sample solution

Tolerances: NLT 80% (Q) of the labeled amount of pindolol (C₁₄H₂₀N₂O₂) is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS (905)

Meet the requirements

5 IMPURITIES

ORGANIC IMPURITIES

Solution A: 0.05 M sodium acetate. Adjust with glacial acetic acid to a pH of 5.0.

Mobile phase: Acetonitrile and Solution A (50:50)

System suitability solution: 0.003 mg/mL of USP Pindolol RS and 0.005 mg/mL of USP Indole RS in Mobile phase

Standard solution: 0.003 mg/mL of USP Pindolol RS in Mobile phase

Sensitivity solution: 1.0 µg/mL of USP Pindolol RS from Standard solution in Mobile phase

Sample solution: Nominally 1 mg/mL of pindolol in Mobile phase prepared as follows. Transfer a portion of the powdered Tablets (NLT 25), equivalent to 100 mg of pindolol, to a 100-mL volumetric flask. Add 90 mL of Mobile phase and sonicate for 5 min. Dilute with Mobile phase to volume.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: 264 nm

Column: 4.6-mm x 15-cm; 3-µm packing L10

Flow rate: 1 mL/min

Injection volume: 10 µL

Run time: NLT 3 times of the retention time of pindolol

System suitability

Samples: System suitability solution, Standard solution, and Sensitivity solution

[NOTE-See Table 1 for the relative retention times.]

Suitability requirements

Resolution: NLT 7 between indole and pindolol, System suitability solution

Relative standard deviation: NMT 2%, Standard solution

Signal-to-noise ratio: NLT 10, Sensitivity solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of any individual unspecified degradation product in the portion of Tablets taken:

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

r_U = peak response of each unspecified degradation product from the Sample solution

r_S = peak response of pindolol from the Standard solution

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

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

Acceptance criteria: See Table 1.

Table 1

^a For peak identification and resolution measurement.

6 ADDITIONAL REQUIREMENTS

6.1 PACKAGING AND STORAGE

Preserve in well-closed containers, protected from light. Store at controlled room temperature.

6.2 USP REFERENCE STANDARDS (11)

USP Indole RS

Indole.

C₈H₇N 117.15

USP Nortriptyline Hydrochloride RS

USP Pindolol RS