Molecular structure of Tobramycin (CAS NO.32986-56-4) is:

Product Name: Tobramycin
CAS Registry Number: 32986-56-4
IUPAC Name: 4-amino-2-[4,6-diamino-3-[3-amino-6-(aminomethyl)-5-hydroxyoxan-2-yl]oxy-2-hydroxycyclohexyl]oxy-6-(hydroxymethyl)oxane-3,5-diol
Molecular Weight: 467.51448 [g/mol]
Molecular Formula: C₁₈H₃₇N₅O₉
XLogP3-AA: -6.2
H-Bond Donor: 10
H-Bond Acceptor: 14 
EINECS: 251-322-5
Refractive index: 143 ° (C=4, H₂O)
Storage temp.: 2-8°C
Solubility: H₂O: 50 mg/mL, clear, faintly yellow
Melting Point: 178 °C
Surface Tension: 92.6 dyne/cm
Density: 1.52 g/cm³
Flash Point: 422.8 °C
Enthalpy of Vaporization: 128.66 kJ/mol
Boiling Point: 775.4 °C at 760 mmHg
Vapour Pressure: 9.05E-28 mmHg at 25°C
Product Categories: Oligosaccharide Compounds; Aminoglycosides (Antibiotics for Research and Experimental Use); Antibiotics for Research and Experimental Use; Biochemistry; Intermediates & Fine Chemicals; Oligosaccharides; Pharmaceuticals; Peptide Synthesis/Antibiotics

 Tobramycin (CAS NO.32986-56-4) is used to treat various types of bacterial infections, particularly Gram-negative infections. It is also combined with dexamethasone as an ophthalmic solution.

EPA Genetic Toxicology Program.

Safty information about Tobramycin (CAS NO.32986-56-4) is:
Poison by intravenous and subcutaneous routes. Moderately toxic by intramuscular and intraperitoneal routes. An experimental teratogen. When heated to decomposition it emits toxic fumes of NO_x.
Hazard Codes: Xi
Risk Statements: 36/37/38 
R36/37/38:Irritating to eyes, respiratory system and skin.
Safety Statements: 26-37/39 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S37/39:Wear suitable gloves and eye/face protection.
WGK Germany: 2
RTECS: WK2100000
F: 3-10

Tobramycin , its cas register number is 32986-56-4. It also can be called Tobramycin [USAN:INN:BAN:JAN] ; Tobradex ; Tobrasone ; 1-Epitobramycin ; 3'-Deoxykanamycin B ; 4-(2,6-Diamino-2,3,6-trideoxy-alpha-D-glycopyranosyl)-6-(3-amino-3-deoxy-alpha-D-glycopyranosyl)-2-deoxystreptamine ; Aktob ; D-Streptamine, O-3-amino-3-deoxy-alpha-D-glucopyranosyl-(1-6)-O-(2,6-diamino-2,3,6-trideoxy-alpha-D-ribo-hexopyranosyl-(1-4))-2-deoxy- ; Deoxykanamycin B ;  Gotabiotic ; Nebramycin ; O-3-Amino-3-deoxy-alpha-D-glucopyranosyl-(1-4)-O-(2,6-diamino-2,3,6-trideoxy-alpha-D-ribo-hexopyranosyl-(1-6))-2-deoxy-L-streptamine ; O-3-Amino-3-deoxy-alpha-D-lucopyranosyl-(1-6)-O-(2,6-diamino-2,3,6-trideoxy-alpha-D-ibohexopyranosyl-(1-4))-2-deoxy-D-streptamine ; Streptamine, O-3-amino-3-deoxy-alpha-D-glucopyranosyl-(1-4)-O-(2,6-diamino-2,3,6-tyrideoxy-alpha-D-ribohexopyranosyl-(1-6))-2-deoxy-, D- ; Tenebrimycin ; Tenemycin ; Tobacin ; Tobi ; Tobracin ; Tobradistin ; Tobralex ; Tobramaxin ; Tobramicin ; Tobramicina ; Tobramitsetin ; Tobramycetin ; Tobramycine ; Tobramycinum ; Tobrased ; Tobrex ; D-Streptamine, O-3-amino-3-deoxy-alpha-D-glucopyranosyl-(1-6)-O-(2,6-diamino-2,3,6-trideoxy-alpha-D-ribo-hexopyranosyl-(1-4))-2-deoxy- ; Streptamine, O-3-amino-3-deoxy-alpha-D-glucopyranosyl-(1-4)-O-(2,6-diamino-2,3,6-trideoxy-alpha-D-ribohexopyranosyl-(1-6))-2-deoxy-, D- . It is a white solid. Like other aminoglycosides, In genetically susceptible individuals, it can cause deafness or a loss of equilibrioception (vertigo) .It can also be highly toxic to the kidneys, particularly if multiple doses accumulate over a course of treatment. For these reasons, when it is given parenterally, it is usually dosed by body weight. Various formulae exist for calculating tobramycin dosage.