Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Beta2-adrenoceptor agonist; bronchodilator.
DEFINITION
Clenbuterol Granules contain Clenbuterol Hydrochloride.
The granules comply with the requirements stated under Granules and with the following requirements.
Content of clenbuterol hydrochloride, C12H18Cl2N2O,HCl
90.0 to 105.0% of the stated amount.
IDENTIFICATION
In the Assay, record the UV spectrum of the principal peak in the chromatograms obtained with solutions (1) and (2) with a diode array detector in the range of 200 to 400 nm:
the UV spectrum of the principal peak in the chromatogram obtained with solution (1) is similar to that of the peak in the chromatogram obtained with solution (2);
the retention time of the principal peak in the chromatogram obtained with solution (1) is similar to that of the peak in the chromatogram obtained with solution (2).
TESTS
Related substances
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
Solution A 25 volumes of methanol R1 and 75 volumes of a solution containing 0.435% w/v dipotassium hydrogen orthophosphate, adjusted to pH 3.0 with orthophosphoric acid.
(1) Mix with the aid of ultrasound a quantity of the granules containing 0.064 mg of Clenbuterol Hydrochloride in 10 mL of solution A. Centrifuge and filter through a 0.45-µm membrane filter (Whatman RC is suitable), discarding the first 1 mL of the filtrate.
(2) Dilute 1 volume of solution (1) to 100 volumes with solution A.
(3) 63 ng per mL each of clenbuterol impurity B EPCRS and clenbuterol impurity D BPCRS in solution A.
(4) Dilute 1 volume of solution (2) to 10 volumes with solution A.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (15 cm × 4.6 mm) packed with end-capped octadecylsilyl silica gel for chromatography (5 µm) (Reprosil Pur ODS-3 is suitable) fitted with a pre-column (0.5 cm × 4 mm) packed with the same material.
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 1 mL per minute.
(d) Use a column temperature of 30°.
(e) Use detection wavelengths of 211 nm and 320 nm.
(f) Inject 100 µL of each solution.
(g) Allow the chromatography to proceed for twice the retention time of clenbuterol.
MOBILE PHASE
20 volumes of methanol R1 and 80 volumes of a solution containing 0.435% w/v dipotassium hydrogen orthophosphate adjusted to pH 3.0 with orthophosphoric acid.
When the chromatograms are recorded under the prescribed conditions, the relative retentions with reference to clenbuterol (retention time about 26 minutes) are: impurity D, about 0.4 and impurity B, about 0.6.
SYSTEM SUITABILITY
The test is not valid unless, in the chromatogram obtained with solution (3) at 211 nm, the resolution between the peaks due to impurity D and impurity B is at least 8.0.
LIMITS
At 320 nm
Identify any peak corresponding to impurity D in the chromatogram obtained with solution (1), using the chromatogram obtained with solution (3), and multiply the area of this peak by a correction factor of 0.5.
In the chromatogram obtained with solution (1), the area of any peak corresponding to impurity B or impurity D is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (1% of each).
At 211 nm
In the chromatogram obtained with solution (1):
the area of any secondary peak, excluding any peaks due to impurity B or impurity D, is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (1%).
Disregard any peak with an area less than 3 times the area of the principal peak in the chromatogram obtained with solution (4) (0.3%).
The total impurity content is not greater than 3.0%.
ASSAY
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
Solution A 25 volumes of methanol R1 and 75 volumes of a solution of 0.435% w/v dipotassium hydrogen orthophosphate, adjusted to pH 3.0 with orthophosphoric acid.
(1) Mix with the aid of ultrasound a quantity of the granules containing 0.064 mg of Clenbuterol Hydrochloride in 10 mL of solution A. Centrifuge and filter through a 0.45-µm membrane filter (Whatman RC is suitable), discarding the first 1 mL of the filtrate.
(2) 0.00064% w/v of clenbuterol hydrochloride BPCRS in solution A.
CHROMATOGRAPHIC CONDITIONS
The chromatographic conditions described under Related Substances may be used with a detection wavelength of 211 nm.
DETERMINATION OF CONTENT
Calculate the content of clenbuterol hydrochloride, C12H18Cl2N2O,HCl, in the granules from the chromatograms obtained and using the declared content of C12H18Cl2N2O,HCl in clenbuterol hydrochloride BPCRS.
STORAGE
Clenbuterol Granules should be protected from light.
IMPURITIES
The impurities limited by the requirements of this monograph include impurities B and D listed under Clenbuterol Hydrochloride.
