Action and use
Beta2-adrenoceptor agonist; bronchodilator.
Definition
Salbutamol Tablets contain Salbutamol Sulfate.
The tablets comply with the requirements stated under Tablets and with the following requirements.
Content of salbutamol, C13H21NO3
92.5 to 107.5% of the stated amount.
Identification
A. Carry out the method described under Related substances applying separately to the plate 2 µL of each of the following solutions. For solution (1) shake a quantity of the powdered tablets containing the equivalent of 10 mg of salbutamol with 10 mL of
methanol (
80%) and filter. Solution (2) contains 0.12% w/v of
salbutamol sulfate BPCRS. The principal spot in the chromatogram obtained with solution (1) corresponds to that in the chromatogram obtained with solution (2).
B. Shake a quantity of the powdered tablets containing the equivalent of 2.5 mg of salbutamol with 50 mL of a 2% w/v solution of
sodium tetraborate, add 1 mL of a 3% w/v solution of
4-aminophenazone, 10 mL of a 2% w/v solution of
potassium hexacyanoferrate(
iii) and 10 mL of
chloroform, shake and allow to separate. An orange-red colour is produced in the chloroform layer.
C. Shake a quantity of the powdered tablets containing the equivalent of 4 mg of salbutamol with 10 mL of
water and filter. The filtrate yields the reactions characteristic of
sulfates,
Appendix VI.
Tests
Related substances
Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.
(1) Shake a quantity of the tablets containing the equivalent of 48 mg of salbutamol with 60 mL of
ethanol (
50%) for 30 minutes, filter, evaporate to dryness using a rotary evaporator and gentle heat and dissolve the residue in 2 mL of
water; if the residue is coloured, pass the final solution through a column (3 cm × 6 mm) packed with
activated acid aluminium oxide (Brockmann Grade I is suitable).
chromatographic conditions
(b) Use the mobile phase as described below.
(c) Apply 10 µL of each solution.
(d) Develop the plate to 18 cm.
(e) After removal of the plate, dry in air, spray with a 0.1% w/v solution of
3-methylbenzothiazolin-2-one hydrazone hydrochloride in
methanol (
90%) followed by a 2% w/v solution of
potassium hexacyanoferrate(
iii) in a mixture of 1 volume of 18
m ammonia and 3 volumes of
water and spray again with the solution of methylbenzothiazolinone hydrazone hydrochloride.
mobile phase
3 volumes of 13.5m ammonia, 18 volumes of water, 35 volumes of ethyl acetate, 45 volumes of propan-2-ol and 50 volumes of 4-methylpentan-2-one.
limits
Any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2) (2%) and not more than one such spot is more intense than the spot in the chromatogram obtained with solution (3) (0.75%).
Uniformity of content
Tablets containing less than the equivalent of 2 mg and/or less than 2% w/w of salbutamol comply with the requirements stated under Tablets using the following method of analysis. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Add 50 mL of
water to one tablet, shake for 1 hour, add sufficient
water to produce 100 mL, mix, centrifuge and use the supernatant liquid.
chromatographic conditions
(a) Use a stainless steel column (20 cm × 5 mm) packed with spherical particles of silica, 5 µm in diameter, the surface of which has been modified with chemically-bonded nitrile groups (Spherisorb CN is suitable).
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 2.0 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 276 nm.
(f) Inject 20 µL of each solution.
mobile phase
5 volumes of propan-2-ol, 30 volumes of 0.05m ammonium acetate and 65 volumes of water; adjust the pH of the mixture to 4.5 with glacial acetic acid.
system suitability
The test is not valid unless, in the chromatogram obtained with solution (2), the resolution between the two principal peaks is at least 1.5.
determination of content
Calculate the content of C13H21NO3 in each tablet using the declared content of C13H21NO3 in salbutamol sulfate BPCRS.
Assay
For tablets containing the equivalent of less than 2 mg and/or less than 2% w/w of salbutamol
Use the average of the individual results determined in the test for Uniformity of content.
For tablets containing the equivalent of 2 mg or more and 2% w/w or more of salbutamol
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Shake 10 tablets with 100 mL of
water for 1 hour, add sufficient
water to produce a solution containing the equivalent of 0.040% w/v of salbutamol, mix, centrifuge and use the supernatant liquid.
chromatographic conditions
The chromatographic conditions described under Uniformity of content may be used.
system suitability
The test is not valid unless, in the chromatogram obtained with solution (2), the resolution between the two principal peaks is at least 1.5.
determination of content
Calculate the content of C13H21NO3 in the tablets using the declared content of C13H21NO3 in salbutamol sulfate BPCRS.
Labelling
The quantity of active ingredient is stated in terms of the equivalent amount of salbutamol.