Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Cyclo-oxygenase inhibitor; analgesic; anti-inflammatory.
DEFINITION
Benzydamine Cream contains Benzydamine Hydrochloride in a suitable basis.
The cream complies with the requirements stated under Topical Semi-solid Preparations and with the following requirements.
Content of benzydamine hydrochloride, C19H23N3O,HCl
92.5 to 107.5% of the stated amount.
IDENTIFICATION
A. Heat a quantity of the cream containing 25 mg of Benzydamine Hydrochloride with 50 mL of absolute ethanol until the cream is completely dissolved and place in an ice-bath until a white precipitate forms. Allow to warm to 20°, dilute to 100 mL with absolute ethanol and filter. Dilute 10 mL of the filtrate to 100 mL with absolute ethanol. The light absorption of the resulting solution, Appendix II B, in the range 230 to 350 nm exhibits a maximum at 308 nm.
B. In the test for 1-Benzyl-1H-indazol-3-ol, the principal spot in the chromatogram obtained with solution (1) corresponds to that in the chromatogram obtained with solution (2).
TESTS
1-Benzyl-1H-indazol-3-ol
Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions in methanol.
(1) Extract a quantity of the cream containing 60 mg of Benzydamine Hydrochloride with 25 mL of hot methanol, cool the solution in ice and filter; repeat the extraction twice, filtering each extract and evaporate the combined extracts to dryness using a rotary evaporator; dissolve the residue in 5 mL of methanol.
(2) 1.2% w/v of benzydamine hydrochloride BPCRS.
(3) 0.0024% w/v of 1-benzyl-1H-indazol-3-ol BPCRS.
CHROMATOGRAPHIC CONDITIONS
(a) Use as the coating silica gel GF254.
(b) Use the mobile phase as described below.
(c) Apply 40 μL of each solution.
(d) Develop the plate to 15 cm.
(e) After removal of the plate, dry in air and examine under ultraviolet light (254 nm and 365 nm).
MOBILE PHASE
30 volumes of triethylamine and 80 volumes of toluene.
LIMITS
By each method of visualisation, any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (3) (0.2%).
ASSAY
To a quantity of the cream containing 25 mg of Benzydamine Hydrochloride add 50 mL of ethanol (96%), heat until the cream is completely dissolved and cool in an ice-bath until a white precipitate forms. Allow to warm to 20°, dilute to 100 mL with ethanol (96%) and filter. Dilute 10 mL of the filtrate to 100 mL with ethanol (96%) and measure the absorbance of the resulting solution at the maximum at about 308 nm, Appendix II B, using ethanol (96%) in the reference cell. Calculate the content of C19H23N3O,HCl from the absorbance obtained with a solution containing 0.0025% w/v of benzydamine hydrochloride BPCRS in ethanol (96%) and using the declared content of C19H23N3O,HCl in benzydamine hydrochloride BPCRS.
