Action and use
Glucocorticoid.
DEFINITION
Prednisolone Sodium Phosphate Eye Drops are a sterile solution of Prednisolone Sodium Phosphate in Purified Water.
The eye drops comply with the requirements stated under Eye Preparations and with the following requirements.
Content of prednisolone sodium phosphate, C21H27Na2O8P
90.0 to 110.0% of the stated amount.
IDENTIFICATION
For eye drops containing less than 0.1% w/v of Prednisolone Sodium Phosphate carry out test B only.
A. Carry out the method for thin-layer chromatography, Appendix III A, using silica gel GF254 as the coating substance and a mixture of 33 volumes of water, 47 volumes of glacial acetic acid and 120 volumes of butan-1-ol, prepared immediately before use, as the mobile phase. Apply separately to the plate 10 μL of each of the following solutions. For solution (1) use the eye drops diluted, if necessary, with water to contain 0.1% w/v of Prednisolone Sodium Phosphate. Solution (2) contains 0.1% w/v of prednisolone sodium phosphate BPCRS in water. Solution (3) is a mixture of equal volumes of solutions (1) and (2). Solution (4) is a mixture of equal volumes of solution (2) and a 0.1% w/v solution of betamethasone sodium phosphate BPCRS in water. After removal of the plate, allow it to dry in air, heat at 110° for 10 minutes and examine under ultraviolet light (254 nm). The chromatograms obtained with solutions (1), (2) and (3) show single principal spots with similar Rf values. The chromatogram obtained with solution (4) shows two principal spots with almost identical Rf values.
B. In the Assay, the chromatogram obtained with solution (1) shows a peak with the same retention time as the peak due to prednisolone sodium phosphate in the chromatogram obtained with solution (2).
C. To a volume containing 0.2 mg of Prednisolone Sodium Phosphate slowly add 1 mL of sulfuric acid and allow to stand for 2 minutes. A deep red colour is produced.
TESTS
Acidity or alkalinity
pH, 7.0 to 8.5, Appendix V L.
Free prednisolone
Carry out the method for liquid chromatography, Appendix III D. For eye drops containing 0.010% w/v or more of Prednisolone Sodium Phosphate use 50 μL of the following solutions. Solution (1) contains 0.00040% w/v of prednisolone BPCRS in the mobile phase. Prepare solution (2) in the following manner. Dilute the eye drops, if necessary, with the mobile phase to produce a solution containing 0.010% w/v of Prednisolone Sodium Phosphate.
For eye drops containing less than 0.010% w/v of Prednisolone Sodium Phosphate, use 0.2 mL of the following solutions. Solution (1) contains 0.00004% w/v of prednisolone BPCRS in the mobile phase. For solution (2) dilute the eye drops, if necessary, with the mobile phase to produce a solution containing 0.0010% w/v of Prednisolone Sodium Phosphate.
The chromatographic procedure may be carried out using (a) a stainless steel column (20 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (10 μm) (Spherisorb ODS 1 is suitable), (b) a mixture of 45 volumes of methanol and 55 volumes of citro-phosphate buffer pH 5.0 as the mobile phase with a flow rate of 2 mL per minute and (c) a detection wavelength of 247 nm.
In the chromatogram obtained with solution (2) the area of any peak corresponding to prednisolone is not greater than the area of the principal peak in the chromatogram obtained with solution (1) (4%).
ASSAY
Carry out the method for liquid chromatography, Appendix III D, using 50 μL of the following solutions. For solution (1) dilute a quantity of the eye drops, if necessary, to contain 0.001% w/v of Prednisolone Sodium Phosphate. For solution (2) dissolve 10 mg of prednisolone sodium phosphate BPCRS in sufficient water to produce 100 mL (solution A) and dilute 10 mL of the solution to 100 mL. For solution (3) add 10 mL of a 0.01% w/v solution of betamethasone sodium phosphate BPCRS in water to 10 mL of solution A and dilute to 100 mL with water.
The chromatographic procedure may be carried out using (a) a stainless steel column (20 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (10 μm) (Spherisorb ODS 1 is suitable), (b) a mixture of 45 volumes of methanol and 55 volumes of citro-phosphate buffer pH 5.0 as the mobile phase with a flow rate of 2 mL per minute and (c) a detection wavelength of 247 nm.
The assay is not valid unless the resolution factor between the peaks due to betamethasone sodium phosphate and prednisolone sodium phosphate in the chromatogram obtained with solution (3) is at least 2.5.
Calculate the content of C21H27Na2O8P in solution A by measuring the absorbance, Appendix II B, of a solution obtained by diluting 1 volume of solution A to 4 volumes with water at the maximum at 247 nm and taking 312 as the value of A(1%, 1 cm) at the maximum at 247 nm. Calculate the content of C21H27Na2O8P in the eye drops using peak areas.
STORAGE
Prednisolone Sodium Phosphate Eye Drops should be stored protected from light.
