Loxapine Succinate
C18H18ClN3O·C4H6O4 445.90

Butanedioic acid, compd. with 2-chloro-11-(4-methyl-1-piperazinyl)dibenz[b,f][1,4]oxazepine(1:1).
2-Chloro-11-(4-methyl-1-piperazinyl)dibenz[b,f][1,4] oxazepine succinate (1:1) [27833-64-3].
» Loxapine Succinate contains not less than 98.5 percent and not more than 101.0 percent of C18H18ClN3O·C4H6O4, calculated on the dried basis.
Packaging and storage— Preserve in tight containers.
B: Ultraviolet Absorption 197U
Solution: 20 µg per mL.
Medium: 0.01 N hydrochloric acid.
Melting range, Class I 741: between 150 and 153.
Loss on drying 731 Dry it at 105 for 4 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Chromatographic purity—
Standard preparations— Dissolve USP Loxapine Succinate RS in methanol and mix to obtain Standard preparation A having a known concentration of 0.5 mg per mL. Dilute portions of Standard preparation A quantitatively with methanol to obtain Standard preparation B and Standard preparation C having known concentrations of 0.25 mg per mL and 0.1 mg per mL, respectively.
Test preparation— Dissolve an accurately weighed quantity of Loxapine Succinate in methanol to obtain a solution containing 50 mg per mL.
Procedure— Separately apply 5 µL of the Test preparation and each of the three Standard preparations to a suitable high performance thin-layer chromatographic plate (see Chromatography 621) coated with a 0.10-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 ethyl acetate, methanol, and ammonium hydroxide (9:1:0.1) 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, air-dry, examine the plate under short-wavelength UV light, and compare the intensities of any secondary spots observed in the chromatogram of the Test preparation with those of the principal spots in the chromatograms of the Standard preparations: no secondary spot from the chromatogram of the Test preparation is larger or more intense than the principal spot obtained from Standard preparation A (1.0%), and the sum of the intensities of the secondary spots obtained from the Test preparation corresponds to not more than 2.0%.
Assay— Dissolve about 400 mg of Loxapine Succinate, accurately weighed, in 80 mL of glacial acetic acid, and titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 22.29 mg of C18H18ClN3O·C4H6O4.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Ravi Ravichandran, Ph.D.
Senior Scientist
(MDPP05) Monograph Development-Psychiatrics and Psychoactives
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 2817
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.