Tiotropium Bromide

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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C₁₉H₂₂BrNO₄S₂         472.41

3-Oxa-9-azoniatricyclo[3.3.1.0^2.4]nonane, 7-[(hydroxydi-2-thienacetyl)oxy]-9,9-dimethyl-, bromide, (1α,2β, 4β,5α, 7β)-;

(1R,2R,4S,5S,7s)-7-(2-Hydroxy-2,2-di(thiophen-2-yl)acetoxy)-9,9-dimethyl-3-oxa-9-azatricyclo[3.3.1.0^2.4]nonan-9-ium bromide CAS RN^®: 136310-93-5; UNII: XX112XZP0J.

Tiotropium bromide monohydrate

C₁₉H2₂BrNO₄S₂ · H₂O              490.43 CAS RN^®: 411207-31-3; UNII: L64SX0195N.

1 DEFINITION

Tiotropium Bromide contains NLT 98.0% and NMT 102.0% of tiotropium bromide (C₁₉H₂₂BrNO₄S₂), calculated on the anhydrous basis. 

2 IDENTIFICATION

A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197A, 197K, or 197M

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

C. IDENTIFICATION TESTS-GENERAL (191), Chemical Identification Tests, Bromide

Sample solution: 10 mg/mL of Tiotropium Bromide in water

Acceptance criteria: Meets the requirements of test B (silver nitrate precipitate test)

3 ASSAY

PROCEDURE

Protect solutions containing tiotropium bromide from light.

Buffer: 5 g/L of monobasic potassium phosphate and 1 g/L of sodium methanesulfonate in water. Adjust with 1 M phosphoric acid to a pH of 3.0.

Solution A: Acetonitrile, methanol, and Buffer (40:10:50)

Mobile phase: Buffer and Solution A (78:22)

System suitability solution: 0.1 mg/mL each of USP Tiotropium Bromide RS and USP Tiotropium Related Compound C RS in Solution A

Standard solution: 0.1 mg/mL of USP Tiotropium Bromide RS in Solution A

Sample solution: 0.1 mg/mL of Tiotropium Bromide in Solution A

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 240 nm

Column: 3.0-mm x 15-cm; 3.5-µm packing L56

Column temperature: 50°

Flow rate: 1.2 mL/min

Injection volume: 5 µL

Run time: NLT 1.6 times the retention time of tiotropium

System suitability

Samples: System suitability solution and Standard solution

Suitability requirements

Resolution: NLT 1.5 between tiotropium and tiotropium related compound C, System suitability solution

Tailing factor: NMT 1.8, Standard solution

Relative standard deviation: NMT 0.73%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of tiotropium bromide (C₁₉H₂₂BrNO₄S₂) in the portion of Tiotropium Bromide taken:

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

r_U = peak response of tiotropium from the Sample solution

r_S = peak response of tiotropium from the Standard solution

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

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

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

4 IMPURITIES

4.1 RESIDUE ON IGNITION (281)

NMT 0.1%

4.2 ORGANIC IMPURITIES

Protect solutions containing tiotropium bromide from light.

Solution A: 5 g/L of monobasic potassium phosphate and 1 g/L of sodium methanesulfonate in water. Adjust with 1 M phosphoric acid to a pH of 3.0.

Solution B: Acetonitrile, methanol, and Solution A (40:10:50)

Mobile phase: See Table 1.

Table 1

Standard solution: 20 µg/mL of USP Tiotropium Bromide RS in Solution B

Sample solution: 2000 µg/mL of Tiotropium Bromide in Solution B

System suitability solution: 2 µg/mL of USP Tiotropium Related Compound C RS in the Sample solution

Sensitivity solution: 1 µg/mL of USP Tiotropium Bromide RS in Solution B

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 240 nm

Column: 3.0-mm x 15-cm; 3.5-µm packing L56

Column temperature: 50°

Flow rate: 1.2 mL/min

Injection volume: 5 µL

System suitability

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

Suitability requirements

[NOTE-The relative retention times for tiotropium and tiotropium related compound C are 1.0 and 1.2, respectively.]

Resolution: NLT 2.4 between tiotropium and tiotropium related compound C, System suitability solution

Relative standard deviation: NMT 3.0%, Standard solution

Tailing factor: NMT 1.5, Standard solution

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

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity in the portion of Tiotropium Bromide taken:

                          Result = (r_U/r_S) × (C_S/C_U) × (1/F) × 100

r_U = peak response of each impurity from the Sample solution

r_S = peak response of tiotropium from the Standard solution

C_S = concentration of USP Tiotropium Bromide RS in the Standard solution (µg/mL)

C_U = concentration of Tiotropium Bromide in the Sample solution (µg/mL) 

F = relative response factor for each individual impurity (see Table 2)

Acceptance criteria: See Table 2. The reporting threshold is 0.05%.

Table 2

^a 2-Hydroxy-2,2-di(thiophen-2-yl)acetic acid.

^b Methyl 2-hydroxy-2,2-di(thiophen-2-yl)acetate.

^c Di(thiophen-2-yl)methanone.

4.3 LIMIT OF TIOTROPIUM RELATED COMPOUND G AND TIOTROPIUM RELATED COMPOUND H

Buffer: 3.9 g/L of ammonium acetate in water. Adjust with glacial acetic acid to a pH of 4.0.

Mobile phase: Acetonitrile and Buffer (90:10)

Diluent: 0.01 N hydrochloric acid

Related compound G stock solution: 4 µg/mL of USP Tiotropium Related Compound G. RS in Diluent

Related compound H stock solution: 4 µg/mL of USP Tiotropium Related Compound H RS in Diluent

System suitability solution: 0.04 µg/mL each of USP Tiotropium Related Compound G. RS and USP Tiotropium Related Compound HRS from Related compound G stock solution and Related compound H stock solution in Diluent

Sensitivity solution: 0.01 µg/mL each of USP Tiotropium Related Compound G RS and USP Tiotropium Related Compound H RS from System suitability solution in Diluent

Related compound G standard solution: 0.04 µg/mL of USP Tiotropium Related Compound G RS from Related compound G stock solution in Diluent

Related compound H standard solution: 0.04 µg/mL of USP Tiotropium Related Compound H.RS from Related compound H stock solution in Diluent

Sample solution: 40 µg/mL of Tiotropium Bromide in Diluent prepared as follows. Transfer a suitable amount of Tiotropium Bromide to an appropriate volumetric flask. Add 80% of the flask volume of Diluent. Sonicate for NLT 5 min to dissolve and dilute with Diluent to volume.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: Mass spectrometer

Ionization: Electrospray positive ion. [NOTE-Adjustments to the electrospray source parameters including the probe temperature, cone voltage, and capillary voltage may be necessary to meet Suitability requirements.]

Acquisition mode: Selected ion monitoring (SIM) mode with m/z of 170.1 for both tiotropium related compound G and tiotropium related compound H cations

Column: 3.0-mm x 5-cm; 5-µm packing L9

Column temperature: 20°

Flow rate: 0.6 mL/min

Injection volume: 5 µL

Run time: NLT 1.5 times the retention time of tiotropium related compound G

System suitability

Samples: System suitability solution and Sensitivity solution

[NOTE-The relative retention times for tiotropium related compound H and tiotropium related compound G are 0.85 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 1.5 between tiotropium related compound H and tiotropium related compound G, System suitability solution

Relative standard deviation: NMT 10.0% for tiotropium related compound G and tiotropium related compound H, System suitability solution

Signal-to-noise ratio: NLT 10 for both tiotropium related compound G and tiotropium related compound H, Sensitivity solution

Analysis

Samples: Related compound G standard solution, Related compound H standard solution, and Sample solution

Calculate the percentage of tiotropium related compound G and tiotropium related compound H in the portion of Tiotropium Bromide taken:

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

r_U = peak response of tiotropium related compound G or tiotropium related compound H from the Sample solution

r_S = peak response of tiotropium related compound G or tiotropium related compound H from the corresponding Related compound G standard solution or Related compound H standard solution

C_S = concentration of USP Tiotropium Related Compound G RS in the Related compound G standard solution or USP Tiotropium Related Compound H. RS in the Related compound H standard solution (µg/mL)

C_U = concentration of Tiotropium Bromide in the Sample solution (µg/mL)

Acceptance criteria: NMT 0.10% each of tiotropium related compound G and tiotropium related compound H

5 SPECIFIC TESTS

WATER DETERMINATION (921), Method I. Method la: NMT 4.0%

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Store in tight containers.

USP REFERENCE STANDARDS (11)

USP Tiotropium Bromide RS

USP Tiotrogium Related Compound C RS

(1R,3s,5S)-3-[2-Hydroxy-2,2-di(thiophen-2-yl)acetoxy]-8,8-dimethyl-8-azabicyclo[3.2.1]oct-6-en-8-ium bromide.

C₁₉H₂₂BrNO₄S₂       456.41

USP Tiotropium Related Compound G RS

(1R,2R,4S,5S,7s)-7-Hydroxy-9,9-dimethyl-3-oxa-9-azatricyclo[3.3.1.0^2-4]nonan-9-ium bromide.

C₉H₁₆BrNO₂               250.14

USP Tiotropium Related Compound H.RS

(2RS,3aSR,5RS,6RS, 6aRS)-6-Hydroxy-4,4-dimethylhexahydro-2H-2,5-methanofuro[3,2-b]pyrrol-4-ium bromide (may be a mixture of two stereoisomers).

C₉H₁₆BrNO₂            250.14 _{▲(USP 1-Dec-2022)}