Telmisartan Tablets
DEFINITION
Telmisartan Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of telmisartan (C33H30N4O2).
IDENTIFICATION
•  A. Ultraviolet Absorption 197U: The spectrum of the solution under test corresponds to that of the Standard solution, as obtained in the test for Dissolution.
•  B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
ASSAY
•  Procedure
Diluent:  0.005 N methanolic solution of sodium hydroxide
Buffer:  2.0 g/L ammonium dihydrogen phosphate. Adjust with 1 M phosphoric acid to a pH of 3.0.
Mobile phase:  Methanol and Buffer (70:30)
Standard stock solution:  0.8 mg/mL of USP Telmisartan RS and 0.1 mg/mL of USP Telmisartan Related Compound A RS in Diluent
Standard solution:  0.11 mg/mL of USP Telmisartan RS and 0.013 mg/mL of USP Telmisartan Related Compound A RS in Mobile phase. Pass the solution through a membrane filter of 0.45-µm pore size.
Sample solution:  Transfer NLT 20 Tablets into a suitable volumetric flask, and add about 80% of the volume of Diluent. Swirl to disperse, and sonicate for about 10 min. Allow to cool to room temperature, dilute with Diluent to volume, and mix. Pass the resulting solution through a membrane filter of 0.45-µm pore size. Further dilute quantitatively in Mobile phase to prepare a solution having a concentration of 0.11 mg/mL.
Chromatographic system 
Mode:  LC
Detector:  UV 298 nm
Column:  4.0-mm × 4-cm; 5-µm, packing L1
Column temperature:  40
Flow rate:  0.7 mL/min
Injection size:  5 µL
System suitability 
Sample:  Standard solution
Suitability requirements 
Resolution:  NLT 3 between telmisartan and telmisartan related compound A
Tailing factor:  NMT 2.0 for the telmisartan peak
Capacity factor:  NLT 1.5
Relative standard deviation:  NMT 2.0%
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of telmisartan (C33H30N4O2) in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × 100
rU== peak response of telmisartan from the Sample solution
rS== peak response of telmisartan from the Standard solution
CS== concentration of USP Telmisartan RS in the Standard solution (mg/mL)
CU== nominal concentration of telmisartan in the Sample solution (mg/mL)
Acceptance criteria:  90.0%–110.0%
PERFORMANCE TESTS
Change to read:
•  Dissolution 711
Medium:  pH 7.5 phosphate buffer (prepared by dissolving 13.61 g of potassium dihydrogen phosphate in about 800 mL of water, adjusting with 2 M sodium hydroxide to a pH of 7.5, and diluting with water to 1000 mL); 900 mL
Apparatus 2:  75 rpm
Time:  30 min
Standard solution:  Transfer about 44 mg of USP Telmisartan RS to a 100-mL volumetric flask. Add 1 mL of 0.1 M sodium hydroxide, and dilute with methanol to volume. Dilute this solution quantitatively with Medium to obtain a solution having a final concentration of about 0.011 mg/mL.
Sample solution 
For Tablets labeled to contain 20 mg:  Pass a portion of the solution under test through a suitable filter of 0.45-µm pore size. Further dilute the filtrate with Medium (1:2).
For Tablets labeled to contain 40 mg:  Pass a portion of the solution under test through a suitable filter of 0.45-µm pore size. Further dilute the filtrate with Medium (1:4).
For Tablets labeled to contain 80 mg:  Pass a portion of the solution under test through a suitable filter of 0.45-µm pore size. Further dilute the filtrate with Medium (1:8).(RB 1-Jul-2011)
Detector:  UV 296 nm
Blank:  Medium
Determine the percentage of telmisartan (C33H30N4O2) dissolved:
Result = (AU × CS × V × 100)/(AS × D × L)
AU== absorbance of the Sample solution
CS== concentration of the Standard solution (mg/mL)
V== volume of Medium, 900 mL
D== dilution factor of the Sample solution
L== label claim (mg/Tablet)
Tolerances:  NLT 75% (Q) of the labeled amount of telmisartan (C33H30N4O2) is dissolved.
•  Uniformity of Dosage Units 905: Meet the requirements
IMPURITIES
•  Organic Impurities
Diluent, Buffer, Mobile phase, Sample solution, Chromatographic system, and System suitability:  Proceed as directed in the Assay.
Analysis 
Sample:  Sample solution
Calculate the percentage of each impurity in the portion of Tablets taken:
Result = (rU/rS) × 100
rU== peak response of each individual impurity from the Sample solution
rS== peak response of telmisartan from the Sample solution
Acceptance criteria 
Individual impurities:  NMT 0.2% of any individual impurity
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in well-closed containers, and store at controlled room temperature.
•  USP Reference Standards 11
USP Telmisartan RS Click to View Structure
USP Telmisartan Related Compound A RS
1,7¢-Dimethyl-2¢-propyl-1H,3¢H-2,5¢-bibenzo[d]imidazole.
    C19H20N4        304.39
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Topic/Question Contact Expert Committee
Monograph Sujatha Ramakrishna, Ph.D.
Senior Scientific Liaison
1-301-816-8349
(SM22010) Monographs - Small Molecules 2
711 Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison
1-301-816-8106
(GCDF2010) General Chapters - Dosage Forms
Reference Standards RS Technical Services
1-301-816-8129
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USP35–NF30 Page 4779
Pharmacopeial Forum: Volume No. 35(3) Page 581