Action and use
Alpha-adrenoceptor agonist.
DEFINITION
Xylometazoline Nasal Drops are a solution of Xylometazoline Hydrochloride in Purified Water.
The nasal drops comply with the requirements stated under Nasal Preparations and with the following requirements.
Content of xylometazoline hydrochloride, C16H24N2, HCl
90.0 to 110.0% of the stated amount.
IDENTIFICATION
A. To a volume of the nasal drops containing 50 mg of Xylometazoline Hydrochloride add 5 mL of 1M sodium hydroxide, extract with 10 mL of dichloromethane IR, evaporate to dryness and dissolve the residue in 0.5 mL of dichloromethane IR.
The infrared absorption spectrum of the resulting solution, Appendix II A, is concordant with the reference spectrum of xylometazoline (RS 362).
B. To a volume containing 0.5 mg of Xylometazoline Hydrochloride add 0.2 mL of a 5% w/v solution of sodium nitroprusside and 0.1 mL of 5M sodium hydroxide and allow to stand for 10 minutes. Add 1 mL of a 10% w/v solution of sodium hydrogen carbonate. A violet colour is produced.
TESTS
Acidity
pH, 5.6 to 6.6, Appendix V L.
N-(2-Aminoethyl)-4-tert-butyl-2,6-xylylacetamide
Carry out the method for thin-layer chromatography, Appendix III A, using silica gel HF254 as the coating substance and a mixture of 200 volumes of methanol and 3 volumes of 13.5M ammonia as the mobile phase. Apply separately to the plate 5 μL of each of the following solutions. For solution (1) add a volume of the nasal drops containing 10 mg of Xylometazoline Hydrochloride to 30 mL of water, add 5 mL of 5M sodium hydroxide, mix, extract with three 20 mL quantities of dichloromethane, evaporate the combined extracts to dryness and dissolve the residue in 1 mL of dichloromethane. Solution (2) contains 0.03% w/v of xylometazoline impurity A EPCRS in dichloromethane. After removal of the plate, allow it to dry in air and spray with a solution prepared by dissolving 0.3 g of ninhydrin in a mixture of 100 mL of butan-1-ol and 3 mL of glacial acetic acid. Heat at 100° for 10 minutes, allow to cool, and spray with dilute potassium iodobismuthate solution. Any spot corresponding to xylometazoline impurity A [N-(2-aminoethyl)-4-tert-butyl-2,6- xylylacetamide] in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2).
ASSAY
To a volume of the nasal drops containing 10 mg of Xylometazoline Hydrochloride add 5 mL of water, 10 mL of 2M hydrochloric acid and 10 mL of dichloromethane and shake for 1 minute. Discard the dichloromethane layer and repeat the extraction with two further 10 mL quantities of dichloromethane. Add to the aqueous extract 10 mL of 5M sodium hydroxide and 10 mL of dichloromethane, shake for 1 minute and allow to separate. Filter the dichloromethane extract through glass wool and repeat the extraction with four further 10 mL quantities of dichloromethane. Evaporate the combined dichloromethane extracts almost to dryness on a water bath, removing the final traces of solvent in a current of air, and dissolve the residue in 10 mL of 0.01M hydrochloric acid. To 2 mL of this solution add 3 mL of water, 2.5 mL of 1M sodium hydroxide and 2.5 mL of a 5% w/v solution of sodium nitroprusside, mix and allow to stand protected from light for 10 minutes. Add 10 mL of a freshly prepared 8.3% w/v solution of sodium hydrogen carbonate, dilute to 100 mL with water, allow to stand protected from light for 10 minutes and measure the absorbance of the resulting solution at the maximum at 560 nm, Appendix II B, using in the reference cell a solution prepared by treating 5 mL of water and 2.5 mL of 1M sodium hydroxide in the same manner, beginning at the words ‘and 2.5 mL of a 5% w/v solution of sodium nitroprusside …’.
Repeat the operation using a 0.1% w/v solution of xylometazoline hydrochloride BPCRS, diluted if necessary with water, in place of the nasal drops. Calculate the content of C16H24N2, HCl in the nasal drops from the absorbances obtained using the declared content of C16H24N2, HCl in xylometazoline hydrochloride BPCRS.
STORAGE
Xylometazoline Nasal Drops should be protected from light.
