Action and use
Local anaesthetic.
DEFINITION
Oxybuprocaine Eye Drops are a sterile solution of Oxybuprocaine Hydrochloride in Purified Water.
The eye drops comply with the requirements stated under Eye Preparations and with the following requirements.
Content of oxybuprocaine hydrochloride, C17H28N2O3, HCl
90.0 to 110.0% of the stated amount.
IDENTIFICATION
A. To a quantity of the eye drops containing 0.4% w/v of Oxybuprocaine Hydrochloride add 0.5 mL of 2M hydrochloric acid and 0.5 mL of a 10% w/v solution of sodium nitrite and mix. Add a solution prepared by dissolving 0.2 g of 2-naphthol in the minimum volume of 18M ammonia; a red precipitate is produced.
B. In the Assay, the chromatogram obtained with solution (1) shows a peak with the same retention time as the principal peak in the chromatogram obtained with solution (2).
C. Yield reaction A characteristic of chlorides, Appendix VI.
TESTS
Acidity
pH, 3.5 to 4.3, Appendix V L.
Related substances
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Dilute a volume of the eye drops with sufficient of the mobile phase to produce a solution containing 0.016% w/v of Oxybuprocaine Hydrochloride.
(2) Dilute 1 volume of solution (1) to 100 volumes with the mobile phase.
(3) Mix 1 volume of solution (1) with 1 volume of a 4% w/v solution of sodium hydroxide and allow to stand for 20 minutes. Add 1 volume of 2M orthophosphoric acid, dilute to 100 volumes with the mobile phase and dilute 1 volume of the final solution to 4 volumes with the mobile phase (generation of 4-amino-3-butoxybenzoic acid).
CHROMATOGRAPHIC CONDITIONS
The chromatographic conditions described under Assay may be used.
SYSTEM SUITABILITY
The test is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the two principal peaks is at least 2.0.
LIMITS
In the chromatogram obtained with solution (1): the sum of the areas of any secondary peaks is not greater than 3 times the area of the principal peak in the chromatogram obtained with solution (2) (3%).
ASSAY
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Dilute a suitable volume of the eye drops with sufficient of the mobile phase to produce a solution containing 0.016% w/v of Oxybuprocaine Hydrochloride.
(2) 0.016% w/v of oxybuprocaine hydrochloride BPCRS in the mobile phase.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (15 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 μm) (Hypersil ODS is suitable).
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 1 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 235 nm.
(f) Inject 20 μL of each solution.
MOBILE PHASE
40 volumes of acetonitrile containing 0.1% v/v of diethylamine and 60 volumes of a 0.75% w/v solution of ammonium acetate which has been adjusted to pH 5.0 with glacial acetic acid.
DETERMINATION OF CONTENT
Calculate the content of C17H28N2O3, HCl in the eye drops using the declared content of C17H28N2O3, HCl in oxybuprocaine hydrochloride BPCRS.
STORAGE
Oxybuprocaine Eye Drops should be protected from light. They should not be allowed to freeze.
