303-50-4: Cyclobenzaprine Related Compound B (free base)
Cyclobenzaprine Related Compound B (HCl) (CAS No.: 438-59-5) or Cyclobenzarpine-N-Desmethyl is a hydrochloride salt impurity of Cyclobenzaprine Related Compound B. Cyclobenzaprine is a tricyclic structured compound known to have muscle relaxant activity and is believed to be metabolized by polymorphic cytochrome P4502D6 in human liver microsomes.
"Hucker, Howard B., and Susan C. Stauffer. “GLC Determination of Cyclobenzaprine in Plasma and Urine.” Journal of Pharmaceutical Sciences, vol. 65, no. 8, Aug. 1976, pp. 1253–55, https://doi.org/10.1002/jps.2600650832.?Wang, R. W., et al. “Identification of Human Liver Cytochrome P450 Isoforms Involved in the in Vitro Metabolism of Cyclobenzaprine.” Drug Metabolism and Disposition, vol. 24, no. 7, American Society for Pharmacology and Experimental Therapeutics, July 1996, pp. 786–91, dmd.aspetjou