Tinidazole Tablets

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

Tinidazole Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of tinidazole (C₈H₁₃N₃O₄S)

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

3 ASSAY

PROCEDURE

Buffer: 1.36 g/L of monobasic potassium phosphate in water

Mobile phase: Methanol and Buffer (20:80)

Standard solution: 0.1 mg/mL of USP Tinidazole RS in Mobile phase

Sample stock solution: Nominally 5 mg/mL of tinidazole from Tablets prepared as follows. Transfer an equivalent of about 500 mg of tinidazole from finely powdered Tablets (NLT 20), to a 100-mL volumetric flask. Add 75 mL of Mobile phase, mix thoroughly, and sonicate for 5 min. Cool to room temperature and dilute with Mobile phase to volume. Pass through a filter of 0.45-µm pore size and discard the first 8-10 mL of the filtrate. 

Sample solution: Nominally 0.1 mg/mL of tinidazole in Mobile phase from Sample stock solution

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 315 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 L1

Flow rate: 1 mL/min

Injection volume: 20 µL

Run time: NLT 2.6 times the retention time of tinidazole

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: 0.8-2.0

Relative standard deviation: NMT 1.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of tinidazole (C₈H₁₃N₃O₄S) in the portion of Tablets taken:

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

r_U = peak response of tinidazole from the Sample solution

r_S = peak response of tinidazole from the Standard solution

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

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

Acceptance criteria: 90.0%-110.0%

4 PERFORMANCE TESTS

4.1 DISSOLUTION (711)

Medium: Water; 900 mL

Apparatus 1: 100 rpm

Time: 30 min

Standard solution: 0.0555 mg/mL of USP Tinidazole RS in Medium

Sample solution: Pass a portion of the solution under test through a suitable filter of 0.45-µm pore size, and dilute with Medium to obtain a concentration similar to that of the Standard solution.

Instrumental conditions

Mode: UV

Analytical wavelength: 277 nm

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of tinidazole (C₈H₁₃N₃O₄S) dissolved:

                          Result = (A_U/A_S) x C_S x V x D x (1/L) x 100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

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

V = volume of Medium, 900 mL

D = dilution factor for the Sample solution

L = label claim (mg/Tablet)

Tolerances: NLT 80% (Q) of the labeled amount of tinidazole (CHNOS) is is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS (905), Weight Variation

Meet the requirements

5 IMPURITIES

ORGANIC IMPURITIES

Buffer, Mobile phase, Sample stock solution, and Chromatographic system: Proceed as directed in the Assay.

Sensitivity solution: 0.0005 mg/mL of USP Tinidazole RS in Mobile phase

System suitability solution: 0.01 mg/mL each of USP Tinidazole Related Compound A RS and USP Tinidazole Related Compound B RS in Mobile phase

Standard solution: 0.001 mg/mL of USP Tinidazole RS and 0.002 mg/mL each of USP Tinidazole Related Compound A RS and USP Tinidazole Related Compound B RS in Mobile phase

Sample solution: Nominally 1 mg/mL of tinidazole from Sample stock solution in Mobile phase

System suitability

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

Suitability requirements

Resolution: NLT 1.5 between tinidazole related compound A and tinidazole related compound B, System suitability solution

Relative standard deviation: NMT 5.0% each for tinidazole, tinidazole related compound A, and tinidazole related compound B, Standard solution

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

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of tinidazole related compound A and tinidazole related compound B in the portion of Tablets taken:

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

r_U = peak response of tinidazole related compound A or tinidazole related compound B from the Sample solution

r_S = peak response of tinidazole related compound A or tinidazole related compound B from the Standard solution

C_S = concentration of USP Tinidazole Related Compound A RS or USP Tinidazole Related Compound B RS in the Standard solution (mg/mL)

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

Calculate the percentage of any unspecified impurity in the portion of Tablets taken:

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

r_U = peak response of any unspecified impurity from the Sample solution

r_S = peak response of tinidazole from the Standard solution

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

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

Acceptance criteria: See Table 1. The reporting threshold is 0.05%.

Table 1

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight, light-resistant containers. Store at controlled room temperature.

USP REFERENCE STANDARDS (11)

USP Tinidazole RS

USP Tinidazole Related Compound A RS

2-Methyl-5-nitroimidazole.

C₄H₅N₃O₂           127.10

USP Tinidazole Related Compound B.RS

1-[2-(Ethylsulfonyl)ethyl]-2-methyl-4-nitroimidazole.

C₈H₁₃N₃O₄S              247.27_{▲(USP 1-May-2023)}