1. Introduction of Methylnaltrexone bromide
Methylnaltrexone bromide is one kind of pale pink solid or  white to off-white crystalline powder. The IUPAC Name of this chemical is (4R,4aS,7aR,12bS)-3-(cyclopropylmethyl)-4a,9-dihydroxy-3-methyl-2,4,5,6,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-3-ium-7-one bromide. Besides, Methylnaltrexone bromide belongs to Aromatics;Heterocycles;Intermediates & Fine Chemicals;Metabolites & Impurities;Pharmaceuticals. In addition, the Classification Code of this chemical is Narcotic Antagonists; Treatment of peripheral side effects of opioid therapy. Methylnaltrexone bromide soluble in water, non- hygroscopic.

2. Properties of Methylnaltrexone bromide
Physical properties about Methylnaltrexone bromide are:
(1)ACD/LogP: -3.57; (2)# of Rule of 5 Violations: 0; (3)#H bond acceptors: 5; (4)#H bond donors: 2; (5)#Freely Rotating Bonds: 4; (6)Polar Surface Area: 44.76 Å²; (7)H-Bond Donor: 2; (8)H-Bond Acceptor: 5; (9)Rotatable Bond Count: 2; (10)Tautomer Count: 6; (11)Exact Mass: 435.104521; (12)MonoIsotopic Mass: 435.104521; (13)Topological Polar Surface Area: 66.8; (14)Heavy Atom Count: 27; (15)Formal Charge: 0; (16)Complexity: 664; (17)Isotope Atom Count: 0; (18)Defined Atom StereoCenter Count: 4; (19)Undefined Atom StereoCenter Count: 1; (20)Defined Bond StereoCenter Count: 0; (21)Undefined Bond StereoCenter Count: 0; (22)Covalently-Bonded Unit Count: 2.

3. Structure Descriptors of Methylnaltrexone bromide
You can still convert the following datas into molecular structure: 
(1)SMILES: [Br-].O=C6[C@@H]3Oc1c2c(ccc1O)C[C@@H]4[C@@](O)([C@@]23CC[N+]4(C)CC5CC5)CC6
(2)InChI: InChI=1/C21H25NO4.BrH/c1-22(11-12-2-3-12)9-8-20-17-13-4-5-14(23)18(17)26-19(20)15(24)6-7-21(20,25)16(22)10-13;/h4-5,12,16,19,25H,2-3,6-11H2,1H3;1H/t16-,19+,20+,21-,22?;/m1./s1
(3)InChIKey: IFGIYSGOEZJNBE-KNLJMPJLBL

4. Uses of Methylnaltrexone bromide
Methylnaltrexone bromide is a metabolite of Naltrexone (N285750). It is also a selective μ-opioid receptor antagonist. Besides, Methylnaltrexone bromide functions as a peripherally acting receptor antagonist in tissues of the gastrointestinal tract.