药英教学资料（南京医科大学）TobraDex.pdfVIP

NDA 50-592/S-032 Page 3 TobraDex® (tobramycin and dexamethasone ophthalmic suspension) Sterile DESCRIPTION: TOBRADEX® (tobramycin and dexamethasone ophthalmic suspension) is a sterile, multiple dose antibiotic and steroid combination for topical ophthalmic use. The chemical structures for tobramycin and dexamethasone are presented below: [Tobramycin Structure] Tobramycin Empirical Formula: C H N O 18 37 5 9 Chemical Name: O-3-Amino-3-deoxy- α-D-glucopyranosyl-(1→4)-O-[2,6-diamino-2,3,6-trideoxy-α-D-ribo- hexopyranosyl-(1→6)]-2-deoxy-L-streptamine [Dexamethasone Structure] Dexamethasone Empirical Formula: C22 H29 F O5 Chemical Name: 9-Fluoro-11ß,17,21-trihydroxy-16α-methylpregna-1,4-diene-3,20-dione Each mL of TOBRADEX® (tobramycin and dexamethasone ophthalmic suspension) contains: Active: Tobramycin 0.3% (3 mg) and Dexamethasone 0.1% (1 mg). Preservative: Benzalkonium Chloride 0.01%. Inactives: tyloxapol, edetate disodium, sodium chloride, hydroxyethyl cellulose, sodium sulfate, sulfuric acid and/or sodium hydroxide (to adjust pH) and purified water. CLINICAL PHARMACOLOGY: Corticoids suppress the inflammatory response to a variety of agents and they probably delay or slow healing. Since corticoids may inhibit the bodys defense mechanism against infection, a concomitant antimicrobial drug may be used when this inhibition is considered to be clinically significant. Dexamethasone is a potent corticoid. The antibiotic component in the combination (tobramycin) is included to provide action against susceptible organisms. In vitro studies have demonstrated that tobramycin is active against susceptible strains of the following microorganisms: Staphylococci, including S. aureus and S. epidermidis (coagulase-positive and coagulase-negative), including penicillin-resistant strains. Streptococci, including some of the Group A beta-hemolytic species, some nonhemolytic species, and some S