(may' zin dol).
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C16H13ClN2O 284.74

3H-Imidazo[2,1-a]isoindol-5-ol, 5-(4-chlorophenyl)-2,5-dihydro-, (±)-.
(±)-5-(p-Chlorophenyl)-2,5-dihydro-3H-imidazo[2,1-a]isoindol-5-ol [22232-71-9].
» Mazindol contains not less than 98.0 percent and not more than 102.0 percent of C16H13ClN2O, calculated on the dried basis.
Packaging and storage— Preserve in tight containers.
USP Reference standards 11
USP Mazindol RS Click to View Structure
Clarity and color of solution— A 1 in 100 solution of Mazindol in a mixture of chloroform and methanol (9:1) is clear and not darker in color than a solution prepared by mixing equal volumes of Matching Fluid C (see Color and Achromicity 631) and water.
B: Ultraviolet Absorption 197U
Solution: 10 µg per mL.
Medium: 0.6 N hydrochloric acid.
Absorptivities at 272 nm, calculated on the dried basis, do not differ by more than 3.0%.
Loss on drying 731 Dry it in vacuum at 60 for 2 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Sulfate 221 Triturate a 500-mg portion with 10 mL of water in a mortar. Filter the suspension through a water-washed filter, and rinse the mortar and filter with 30 mL of water, collecting the combined filtrate and washings in a 50-mL color-comparison tube. The filtrate shows no more sulfate than corresponds to 0.20 mL of 0.020 N sulfuric acid (0.04%).
Chromatographic purity— Dissolve 10 mg in 2.0 mL of a mixture of chloroform and methanol (9:1) to obtain the test solution. Dissolve a suitable quantity of USP Mazindol RS in a mixture of chloroform and methanol (9:1) to obtain a Standard solution having a concentration of 5.0 mg per mL. Dilute portions of this solution quantitatively and stepwise with the mixture of chloroform and methanol (9:1) to obtain a series of diluted standard solutions having concentrations of 0.100, 0.050, 0.025, and 0.0125 mg per mL, respectively. Separately apply a 20-µL portion of the test solution and 20-µL portions of the Standard solution and each diluted standard solution to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Allow the spots to dry, and develop the chromatogram in a solvent system consisting of a mixture of chloroform, alcohol, and ammonium hydroxide (80:20:1) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and allow the solvent to evaporate. Locate the spots on the plate by examination under short-wavelength UV light: the chromatograms show principal spots at about the same RF value. Estimate the concentration of any secondary spots present in the chromatogram from the test solution by comparison with the diluted standard solutions: the principal spots from the 0.100, 0.050, 0.025, and 0.0125 mg per mL dilutions are equivalent to 2.0%, 1.0%, 0.50%, and 0.25% of impurities, respectively. No individual impurity is greater than 1.0%, and the sum of the impurities is not greater than 2.0%.
Assay— Transfer about 230 mg of Mazindol, accurately weighed, to a suitable flask, dissolve in 40 mL of glacial acetic acid, add 3 drops of crystal violet TS, and titrate with 0.1 N perchloric acid VS to an emerald-green endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 28.47 mg of C16H13ClN2O.
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Monograph Clydewyn M. Anthony, Ph.D.
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(SM22010) Monographs - Small Molecules 2
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USP35–NF30 Page 3768