Edition: BP 2025 (Ph. Eur. 11.6 update)
Action and use
Antifungal.
DEFINITION
Griseofulvin Premix contains Griseofulvin. The particles of Griseofulvin are generally up to 5 µm in maximum dimension, although larger particles, which may occasionally exceed 30 µm, may be present.
The premix complies with the requirements stated under Premixes and with the following requirements.
Content of griseofulvin, C17H17ClO6
90.0 to 110.0% of the stated amount.
IDENTIFICATION
Shake a quantity of the premix containing 0.1 g of Griseofulvin with 10 mL of dichloromethane. Centrifuge, decant the supernatant liquid, dry with anhydrous sodium sulfate and evaporate the dichloromethane. The infrared absorption spectrum of the residue, Appendix II A, is concordant with the reference spectrum of griseofulvin (RSV 24).
Related substances
Carry out the method for liquid chromatography, Appendix III D, using the following solutions in mobile phase B.
(1) Disperse a quantity of premix containing 0.25 g of Griseofulvin in mobile phase B and dilute to 500 mL.
(2) Dilute 1 volume of solution (1) to 100 volumes.
(3) 0.05% w/v of griseofulvin for system suitability EPCRS.
CHROMATOGRAPHIC CONDITIONS
(a) Use a stainless steel column (25 cm × 4.6 mm) packed with end-capped octadecylsilyl silica gel for chromatography (5 µm) (Discovery C18 is suitable).
(b) Use gradient elution and the mobile phase described below.
(c) Use a flow rate of 1.0 mL per minute.
(d) Use a column temperature of 30°.
(e) Use a detection wavelength of 290 nm.
(f) Inject 10 µL of each solution.
MOBILE PHASE
Mobile phase A 20 volumes of 0.1 % v/v formic acid adjusted to pH 4.5 with dilute ammonia R2 and 80 volumes of water.
Mobile phase B 15 volumes of water, 20 volumes of 0.1 % v/v formic acid adjusted to pH 4.5 with dilute ammonia R2 and 65 volumes of acetonitrile.
| Time (Minutes) | Mobile phase A (% v/v) | Mobile phase B (% v/v) | Comment |
| 0-3 | 50 | 50 | isocratic |
| 3-13 | 50→40 | 50→60 | linear gradient |
| 13-16 | 40→10 | 60→90 | linear gradient |
| 16-24 | 10 | 90 | isocratic |
When the chromatograms are recorded under the prescribed conditions, the relative retention times with reference to griseofulvin (retention time about 16 minutes) are: impurity A, about 0.4; impurity B, about 0.7 and impurity C, about 1.1.
SYSTEM SUITABILITY
The test is not valid unless, in the chromatogram obtained with solution (3), the peak-to-valley ratio is at least 3.0, where Hp is the height above the baseline of the peak due to impurity C and Hv is the height above the baseline of the lowest point of the curve separating this peak from the peak due to griseofulvin.
LIMITS
Identify any peak corresponding to impurity A in the chromatogram obtained with solution (1) and multiply the area of this peak by a correction factor of 0.6.
the area of any peak corresponding to impurity B is not greater than 3 times the area of the principal peak in the chromatogram obtained with solution (2) (3.0%);
the area of any peak corresponding to impurity A is not greater than twice the area of the principal peak in the chromatogram obtained with solution (2) (2.0%);
the area of any other secondary peak is not greater than the area of the principal peak in the chromatogram obtained with solution (2) (1.0%);
the sum of the areas of all secondary peaks is not greater than five times the area of the principal peak in the chromatogram obtained with solution (2) (5.0%).
Disregard any peaks due to excipients and any peak with an area less than 0.3 times the area of the principal peak in the chromatogram obtained with solution (2) (0.3%).
ASSAY
Carry out the method for liquid chromatography, Appendix III D, using the following solutions in mobile phase B.
(1) Disperse a quantity of premix containing 0.25 g of Griseofulvin in mobile phase B and dilute to 500 mL.
(2) 0.05% w/v of griseofulvin for LC assay and identification EPCRS.
CHROMATOGRAPHIC CONDITIONS
The chromatographic conditions described under Related substances may be used.
DETERMINATION OF CONTENT
Calculate the content of C17H17ClO6 in the premix from the chromatograms obtained and using the declared content of C17H17ClO6 in griseofulvin for LC assay and identification EPCRS.
IMPURITIES
The impurities limited by the requirements of this monograph include those listed under Griseofulvin.
