CAS Registry Number: 58895-64-0 Nalmefene HCl Molecular Weight: 375.89 Molecular Formula: C21H25NO3.Nalmefene is the opioid receptor antagonistCAS Registry Number: 58895-64-0 Nalmefene HClMolecular Weight: 375.89 Molecular Formula: C21H25NO3.For any questions, please contact with us!