Miconazole
(mye kon' a zole).
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C18H14Cl4N2O 416.13

1H-Imidazole, 1-2-[(2,4-dichlorophenyl)-2-[(2,4-dichlorophenyl)]methoxy]ethyl]-, (±)-.
(±)-1-[2,4-Dichloro--[(2,4-dichlorobenzyl)oxy]phenethyl]imidazole [22916-47-8].
» Miconazole contains not less than 98.0 percent and not more than 102.0 percent of C18H14Cl4N2O, calculated on the dried basis.
Packaging and storage— Preserve in well-closed containers, protected from light. Store at 25, excursions permitted between 15 and 30.
USP Reference standards 11
USP Miconazole RS Click to View Structure
Identification—
B: Transfer 40 mg to a 100-mL volumetric flask, dissolve in 50 mL of isopropyl alcohol, add 10 mL of 0.1 N hydrochloric acid, dilute with isopropyl alcohol to volume, and mix: the UV absorption spectrum of this solution exhibits maxima and minima at the same wavelengths as that of a similar solution of USP Miconazole RS, concomitantly measured.
Loss on drying 731 Dry it in vacuum at 60 for 4 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.2%.
Chromatographic purity— Dissolve 30 mg in 3.0 mL of chloroform to obtain the Test preparation. Dissolve a suitable quantity of USP Miconazole RS in chloroform to obtain a Standard solution having a concentration of 10.0 mg per mL. Quantitatively dilute a portion of this solution with chloroform to obtain a Diluted standard solution having a concentration of 100 µg per mL. Apply separate 5-µL portions of the three solutions to the starting line of a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Develop the chromatogram in a suitable chamber with a freshly prepared solvent system consisting of a mixture of n-hexane, chloroform, methanol, and ammonium hydroxide (60:30:10:1) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the chamber, and allow the solvent to evaporate. Expose the plate to iodine vapors in a closed chamber for about 30 minutes, and locate the spots: the RF value of the principal spot obtained from the Test solution corresponds to that obtained from the Standard solution, and any other spot obtained from the Test solution does not exceed, in size or intensity, the principal spot obtained from the Diluted standard solution (1.0%).
Assay— Dissolve about 300 mg of Miconazole, accurately weighed, in 40 mL of glacial acetic acid, add 4 drops of p-naphtholbenzein TS, and titrate with 0.1 N perchloric acid VS to a green endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 41.61 mg of C18H14Cl4N2O.
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Pharmacopeial Forum: Volume No. 29(6) Page 1934