Quinine Sulfate
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(C20H24N2O2)2·H2SO4·2H2O 782.94

Cinchonan-9-ol, 6¢-methoxy-, (8,9R)-, sulfate (2:1) (salt), dihydrate.
Quinine sulfate (2:1) (salt) dihydrate [6119-70-6].

Anhydrous 746.93 [804-63-7].
» Quinine Sulfate is the sulfate of an alkaloid obtained from the bark of species of Cinchona. It contains not less than 99.0 percent and not more than 101.0 percent of total alkaloid salt, calculated as (C20H24N2O2)2·H2SO4, on the anhydrous basis.
Packaging and storage— Preserve in well-closed, light-resistant containers.
A: A 1 in 2000 solution in dilute sulfuric acid (1 in 350) exhibits a vivid blue fluorescence. On the addition of a few drops of hydrochloric acid, the fluorescence disappears.
B: In the test for Chromatographic purity, the RF value of the principal spot obtained from the Test preparation corresponds to that from the Standard preparation.
C: A solution (1 in 50) made with the aid of a few drops of hydrochloric acid responds to the tests for Sulfate 191.
Specific rotation 781S: between 235 and 245.
Test solution: 20 mg per mL, in 0.1 N hydrochloric acid.
Water, Method I 921: between 4.0% and 5.5%.
Residue on ignition 281: not more than 0.1%.
Chloroform-alcohol-insoluble substances— Warm 2 g with 15 mL of a mixture of chloroform and dehydrated alcohol (2:1) at about 50 for 10 minutes. Filter through a tared, sintered-glass filter, using gentle suction. Wash the filter with five 10-mL portions of the chloroform-alcohol mixture, dry at 105 for 1 hour, and weigh: the weight of the residue does not exceed 2 mg (0.1%).
Chromatographic purity—
Standard preparation— Prepare a solution of USP Quinine Sulfate RS in diluted alcohol to contain 6 mg per mL.
Diluted standard preparation— Dilute a portion of the Standard preparation with diluted alcohol to a concentration of 0.06 mg per mL.
Related substances preparation— Prepare a solution in diluted alcohol containing in each mL 0.05 mg each of USP Quininone RS (corresponding to 0.06 mg of the sulfate), and 0.10 mg of cinchonidine (corresponding to 0.12 mg of the sulfate).
Test preparation— Prepare a solution of Quinine Sulfate in diluted alcohol to contain 6 mg per mL.
Procedure— Apply 10-µL portions of the Test preparation, the Standard preparation, the Diluted standard preparation, and the Related substances preparation to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel. Allow to dry, and develop the chromatogram in a solvent system consisting of a mixture of chloroform, acetone, and diethylamine (5:4:1), the solvent chamber being used without previous equilibration. When the solvent front has moved about 15 cm, remove the plate from the chamber, mark the solvent front, and allow the solvent to evaporate. Spray the chromatogram with glacial acetic acid. Locate the spots on the plate by examination under long-wavelength UV light. Any spot produced by the Test preparation at the RF value of a spot produced by the Related substances preparation is not greater in size or intensity than that corresponding spot. Apart from these spots and from the spot appearing at the RF value of Quinine Sulfate, any additional fluorescent spot is not greater in size or intensity than the spot of the Diluted standard preparation. Spray the plate with potassium iodoplatinate TS. Any spot produced by the Test preparation is not greater in size or intensity than a corresponding spot from the Related substances preparation.
Limit of dihydroquinine sulfate—
Methanesulfonic acid solution— Add 35.0 mL of methanesulfonic acid to 20.0 mL of glacial acetic acid, dilute with water to 500 mL, and mix.
Diethylamine solution— Dissolve 10.0 mL of diethylamine in water to obtain 100 mL of solution.
Mobile phase— Prepare a suitable filtered and degassed mixture of water, acetonitrile, Methanesulfonic acid solution, and Diethylamine solution (860:100:20:20). Adjust with Diethylamine solution to a pH of 2.6 if found to be lower.
System suitability preparation— Transfer about 10 mg each of quinine sulfate and dihydroquinine to a 50-mL volumetric flask. Dissolve in about 5 mL of methanol, dilute with Mobile phase to volume, and mix.
System suitability test— Chromatograph injections of the System suitability preparation as directed for Procedure: the relative retention times for quinine and dihydroquinine are about 1 and 1.5, respectively. The resolution between the quinine and dihydroquinine peaks is not less than 1.2. The relative standard deviation for the peak response of quinine is not more than 2.0%.
Test preparation— Transfer about 20 mg of Quinine Sulfate to a 100-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix.
Procedure (see Chromatography 621)—Inject about 50 µL of the Test preparation into a chromatograph equipped with a 235-nm detector and a 3.9-mm × 30-cm column that contains packing L1. The response of the dihydroquinine peak is not greater than one-ninth that of the quinine peak (10.0%).
Assay— Dissolve about 200 mg of Quinine Sulfate, accurately weighed, in 20 mL of acetic anhydride, add 4 drops of p-naphtholbenzein TS, and titrate with 0.1 N perchloric acid VS from a 10-mL microburet to a green endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 24.90 mg of total alkaloid salt, calculated as (C20H24N2O2)2·H2SO4.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Behnam Davani, Ph.D., M.B.A.
Senior Scientist
(MDAA05) Monograph Development-Antivirals and Antimicrobials
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 3466
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.