the antibiotics used in the compositions and methods of the present invention have the following formula : y , when taken independently , is ethyl , t - butyl , vinyl , cyclopropyl , 2 - fluoroethyl , p - fluorophenyl , or o , p - difluorophenyl ; w is hydrogen , f , c1 , br , c1 - c4 alkyl , c1 - c4 alkoxy , nh2 or nhch3 ; a is carbon and is taken together with y and the carbon and nitrogen to which a and y are attached to form a five or six membered ring which may contain oxygen or a double bond , and which may have attached thereto r8 which is methyl or methylene ; and r3 , r4 , r5 , r6 , r7 , r9 , r10 and r25 are each independently h , ch3 , ch2nh2 , ch2nhch3 or ch2nhc2h5 , and r5 , r6 , r7 and r9 may also independently be nh2 , nhch3 or nhc2h5 , provided that not more than three of r3 , r4 , r5 , r6 , r7 , r9 , r10 and r25 are other than hydrogen , and if three of these substituents are not hydrogen , at least one of them is methyl . the antibiotics utilized in the present invention also include prodrugs of the compounds of formula ( i ) having a free amino group , as well as pharmaceutically useful hydrates and salts of the compounds of formula ( i ). further details regarding the structure , preparation , and physical properties of trovafloxacin and other compounds of formula ( i ) are provided in u . s . pat . no . 5 , 164 , 402 . the concentrations of the antibiotics of formula ( i ) in the compositions of the present invention will vary depending on the intended use of the compositions ( e . g ., treatment of existing infections or prevention of post - surgical infections ), and the relative antimicrobial activity of the specific antibiotic selected . the antimicrobial activity of antibiotics is generally expressed as the minimum concentration required to inhibit the growth of a specified pathogen . this concentration is also referred to as the “ minimum inhibitory concentration ” or “ mic ”. the term “ mic90 ” refers to the minimum concentration of antibiotic required to inhibit the growth of ninety percent ( 90 %) of the strains of a species . the concentration of an antibiotic required to totally kill a specified bacteria is referred to as the “ minimum bactericidal concentration ” or “ mbc ”. the minimum inhibitory concentration of trovafloxacin for several bacteria commonly associated with ophthalmic , otic and nasal infections are provided in the following table : all of the foregoing concentrations are expressed as micrograms per milliliter (“ mcg / ml ”). the appropriate antibiotic concentration for ophthalmic compositions will generally be an amount of one or more antibiotics of formula ( i ) sufficient to provide a concentration in the aqueous humor and lacrimal fluid of the eye equal to or greater than the mic90 level for the selected antibiotic ( s ) relative to gram - negative and gram - positive organisms commonly associated with ophthalmic infections . the appropriate concentration for otic and nasal compositions will generally be an amount of one or more antibiotics of formula ( i ) sufficient to provide a concentration in the infected tissues equal to or greater than the mic90 level for the selected antibiotic ( s ), relative to gram - negative and gram - positive organisms commonly associated with otic or nasal infections . such amounts are referred to herein as “ an antimicrobial effective amount ”. the compositions of the present invention will typically contain one or more compounds of formula ( i ) in a concentration of from about 0 . 1 to about 1 . 0 percent by weight (“ wt . %”) of the compositions . the compositions of the present invention may also contain one or more anti - inflammatory agents . the anti - inflammatory agents utilized in the present invention are broadly classified as steroidal or non - steroidal . the preferred steroidal anti - inflammatory agents are glucocorticoids . the preferred glucocorticoids for ophthalmic and otic use include dexamethasone , loteprednol , rimexolone , prednisolone , fluorometholone , and hydrocortisone . the preferred glucocorticoids for nasal use include mometasone , fluticasone , beclomethasone , flunisolide , triamcinolone and budesonide . the dexamethasone derivatives described in u . s . pat . no . 5 , 223 , 493 ( boltralik ) are also preferred steroidal anti - inflammatory agents , particularly with respect to compositions for treating ophthalmic inflammation . the following compounds are especially preferred : these compounds are referred to herein as “ 21 - ether derivatives of dexamethasone ”. the 21 - benzyl ether derivative ( i . e .. compound al - 2512 ) is particularly preferred . the preferred non - steroidal anti - inflammatory agents are : prostaglandin h synthetase inhibitors ( cox i or cox ii ), also referred to as cyclooxygenase type i and type ii inhibitors , such as diclofenac , flurbiprofen , ketorolac , suprofen , nepafenac , amfenac , indomethacin , naproxen , ibuprofen , bromfenac , ketoprofen , meclofenamate , piroxicam , sulindac , mefanamic acid , diflusinal , oxaprozin , tolmetin , fenoprofen , benoxaprofen , nabumetome , etodolac , phenylbutazone , aspirin , oxyphenbutazone , ncx - 4016 , hct - 1026 , ncx - 284 , ncx - 456 , tenoxicam and carprofen ; cyclooxygenase type ii selective inhibitors , such as ns - 398 , vioxx , celecoxib , p54 , etodolac , l - 804600 and s - 33516 ; paf antagonists , such as sr - 27417 , a - 137491 , abt - 299 , apafant , bepafant , minopafant , e - 6123 , bn - 50727 , nupafant and modipafant ; pde iv inhibitors , such as ariflo , torbafylline , rolipram , filaminast , piclamilast , cipamfylline , cg - 1088 , v - 11294a . ct - 2820 , pd - 168787 , cp - 293121 dwp - 205297 , cp - 220629 , sh - 636 , bay - 19 - 8004 , and roflumilast ; inhibitors of cytokine production , such as inhibitors of the nfkb transcription factor ; or other anti - inflammatory agents known to those skilled in the art . the concentrations of the anti - inflammatory agents contained in the compositions of the present invention will vary based on the agent or agents selected and the type of inflammation being treated . the concentrations will be sufficient to reduce inflammation in the targeted ophthalmic , otic or nasal tissues following topical application of the compositions to those tissues . such an amount is referred to herein as “ an anti - inflammatory effective amount ”. the compositions of the present invention will typically contain one or more anti - inflammatory agents in an amount of from about 0 . 01 to about 1 . 0 wt .%. the compositions are typically administered to the affected ophthalmic , otic or nasal tissues by topically applying one to four drops of a sterile solution or suspension , or a comparable amount of an ointment , gel or other solid or semisolid composition , one to four times per day . however , the compositions may also be formulated as irrigating solutions that are applied to the affected ophthalmic , otic or nasal tissues during surgical procedures . the ophthalmic , otic , and nasal compositions of the present invention will contain one or more compounds of formula ( i ) and preferably one or more anti - inflammatory agents , in pharmaceutically acceptable vehicles . the compositions will typically have a ph in the range of 4 . 5 to 8 . 0 . the ophthalmic compositions must also be formulated to have osmotic values that are compatible with the aqueous humor of the eye and ophthalmic tissues . such osmotic values will generally be in the range of from about 200 to about 400 milliosmoles per kilogram of water (“ mosm / kg ”), but will preferably be about 300 mosm / kg . ophthalmic , otic , and nasal products are typically packaged in multidose form . preservatives are thus required to prevent microbial contamination during use . suitable preservatives include : polyquaternium - 1 , benzalkonium chloride , thimerosal , chlorobutanol , methyl paraben , propyl paraben , phenylethyl alcohol , edetate disodium , sorbic acid , or other agents known to those skilled in the art . the use of polyquaternium - 1 as the antimicrobial preservative is preferred . typically such preservatives are employed at a level of from 0 . 001 % to 1 . 0 % by weight . the solubility of the components of the present compositions may be enhanced by a surfactant or other appropriate co - solvent in the composition . such co - solvents include polysorbate 20 , 60 , and 80 , polyoxyethylene / polyoxypropylene surfactants ( e . g .. pluronic f - 68 , f - 84 and p - 103 ), cyclodextrin , or other agents knoat to those skilled in the art . typically such co - solvents are employed at a level of from 0 . 01 % to 2 % by weight . the use of viscosity enhancing agents to provide the compositions of the invention with viscosities greater than the viscosity of simple aqueous solutions may be desirable to increase absorption of the active compounds by the target tissues or increase the retention time in the eye , ear or nose . such viscosity building agents include , for example , polyvinyl alcohol , polyvinyl pyrrolidone , methyl cellulose , hydroxy propyl methylcellulose , hydroxyethyl cellulose , carboxymethyl cellulose , hydroxy propyl cellulose or other agents know to those skilled in the art . such agents are typically employed at a level of from 0 . 01 % to 2 % by weight . the following examples are provided to further illustrate the ophthalmic , otic , and nasal compositions of the present invention . the invention has been described herein by reference to certain preferred embodiments . however , as obvious variations thereon will become apparent to those skilled in the art , the invention is not to be considered as limited thereto .
methods of treating or preventing ophthalmic , otic , and nasal infections and attendant inflammation are described . the methods utilize ophthalmic , otic , and nasal compositions containing a new class of antibiotics . the compositions also contain one or more anti - inflammatory agents . the compositions are utilized to treat ophthalmic , otic , and nasal conditions by topically applying the compositions to the affected tissues .