Dissolution
TEST CONDITIONS
(a) Use Apparatus Paddle, rotating the paddle at 50 revolutions per minute.
(b) Use 900 mL of water, at a temperature of 37°C, as the medium.
PROCEDURE
Carry out the method for liquid chromatography, using the following solutions.
Sample solution: After 45 minutes withdraw a sample of the medium and filter. Use the filtered medium, further dilute 10 ml of this solution to 50 ml with water.
Standard solution: Take 50mg of prednisolone ws to a 50 ml volumetric flask. Dilute with methanol to volume. Further dilute 1 ml of this solution to 100 ml with water.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (20 cm × 4.6 mm) packed with octadecylsilyl silica gel for chromatography (5 µm) (Spherisorb ODS 1 is suitable).
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 1.5 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 254 nm.
(f) Inject 20 µL of each solution.
SYSTEM SUITABILITY
The test is not valid unless, in the chromatogram obtained with solution (1), the column efficiency, determined using the peak due to prednisolone, is greater than 15,000 theoretical plates per metre.
DETERMINATION OF CONTENT
Calculate the total content of C21H28O5 in the medium from the chromatograms obtained and using the declared content of C21H28O5 in prednisolone ws.
Calculation:
% Prednisolone =
Spl Area x std wt (mg) x 1 x 900 x 50 x std
potency x 100
Std Area x 50 x 1000 x 5 x 10 x 100
