unless otherwise indicated , all ingredient concentrations are listed as percent ( w / w ). ciprofloxacin is present in the compositions of the invention in an amount effective for anti - bacterial action . such amounts range from about 0 . 01 to about 1 %, preferably from about 0 . 1 to about 0 . 5 %, and most preferably about 0 . 2 %. compositions of the present invention also comprise hydrocortisone as an anti - inflammatory agent . hydrocortisone is present in an amount effective for anti - inflammatory action . such amount typically ranges from about 0 . 1 to about 3 %, preferably about 0 . 1 to about 2 %, and most preferably about 1 %. particularly for ophthalmic use , small particle sizes are preferred . as used herein , “ micronized ” hydrocortisone means hydrocortisone particles having an average particle size ≦ 10 ( μm ( based on surface area ( dsn )). if the particle size of the hydrocortisone raw material as received from the supplier is unsatisfactory , one or more known sizing techniques , such as ball milling or micronizing , can be used to adjust the particle size into the desired range . to prevent contamination by microorganisms and provide a reasonable shelf - life , the compositions of the present invention include a preservative . acceptable preservatives are required to cause no or insignificant ototoxicity , sensitization or irritation of the ear . additionally , the preservative must be jointly soluble with ciprofloxacin in water over a ph range of approximately ph 3 - 6 . the most preferred preservative is benzyl alcohol , which is typically present in an amount from about 0 . 1 to 3 %, preferably about 0 . 1 to 2 %, and most preferably about 0 . 9 %. a tonicity adjusting agent is preferably contained in an amount sufficient to cause the composition to be approximately isotonic , that is an amount effective to adjust the tonicity of the composition from about 150 to about 800 mosm , preferably 200 - 600 mosm . a preferred tonicity - adjusting agent is sodium chloride . a buffering agent is desirable for the compositions of the present invention . the preferred buffering system is an acetate buffer comprising acetic acid and sodium acetate . amounts of sodium acetate and acetic acid effective to buffer the preparation in a ph range of about 4 . 0 - 5 . 3 , preferably about 4 . 4 - 4 . 9 and most preferably about 4 . 7 , range from about 0 . 1 to about 3 % of sodium acetate and from about 0 . 01 to about 10 % of acetic acid . preferably the amount of sodium acetate is from about 0 . 1 to about 2 % and most preferably about 0 . 4 %. preferably the amount of sodium acid is about 0 . 1 to 5 % and most preferably about 0 . 7 %. sodium acetate is preferably used in the form of sodium acetate trihydrate and acetic acid is preferably used in the form of glacial acetic acid . to allow the compositions of the present invention to wet and spread on the skin surface at the site of infection or inflammation in the ear canal , a non - ionic surfactant is desirable . the surfactants known as polysorbates , in particular polysorbates 20 - 80 , are preferred . such polysorbates are commercially available under the tradename tween from ici americas , inc . most preferred is polysorbate 20 . the amount of polysorbate surfactant contained in the compositions of the present invention generally ranges from about 0 . 01 to about 2 %, preferably about 0 . 05 to about 1 %, and most preferably about 0 . 1 %. to help maintain or improve the physical stability of the suspension composition of the present invention , lecithin is added . lecithin is commercially available in at least two grades : a fully hydrogenated soy lecithin comprising 90 % phosphatidylcholine , which is commercially available under the tradename phospholipon 90h from american lecithin company , and a soy lecithin comprising 75 % phosphatidylcholine , which is commercially available under the tradename lipoid - s75 from vernon walden , inc . in general , the amount of lecithin contained in the compositions of the present invention will range from about 0 . 01 to about 5 %, preferably about 0 . 01 to about 2 % and most preferably about 0 . 15 %. in addition to the excipients mentioned above , the ciprofloxacin and hydrocortisone compositions of the present invention comprise polyvinyl alcohol as a viscosity - augmenting agent . the polyvinyl alcohol contained in the composition of the present invention is an 85 - 90 % hydrolyzed grade . preferably , the polyvinyl alcohol ingredient is an 88 % hydrolyzed grade , such as that commercially available as airvol 205s from air products and chemicals , inc . the amount of polyvinyl alcohol ingredient contained in the compositions of the present invention is an amount effective to cause the composition to have a viscosity ranging from about 2 to about 8 cps ( when measured at room temperature using a brookfield viscometer set at 30 rpm and a cp 42 spindle ). preferably , the polyvinyl alcohol ingredient is present in an amount sufficient to cause the composition &# 39 ; s viscosity to be from about 3 to 7 cps . according to a preferred method for preparing the suspension compositions of the present invention , lecithin and surfactant ( 50 % of the required amounts of each ) are dispersed in purified water at a temperature of about 65 - 70 ° c ., then removed from heat . micronized hydrocortisone is added while the lecithin dispersion is cooling and the resulting mixture is mixed overnight ( approximately 12 hours ). separately , a ciprofloxacin solution is prepared by adding the following components in order , allowing each to fully disperse or dissolve before the next is added : remaining 50 % of lecithin , remaining 50 % of surfactant , preservative , buffer ( e . g ., glacial acetic acid then sodium acetate ( trihydrate )), ciprofloxacin , and the tonicity - adjusting agent . the hydrocortisone dispersion is added to the ciprofloxacin solution , then the required amount of polyvinyl alcohol is added from a polyvinyl alcohol stock solution . the following examples are presented to illustrate further various aspects of the present invention , but are not intended to limit the scope of the invention in any respect . each of the formulations in table 1 below was prepared as follows . for a 200 ml batch size , formulations 1 - 6 were prepared using method a and formulations 7 - 11 were prepared using method b . 1 . tare an appropriate sized compounding bottle ( e . g ., 250 ml ) with stir bar . 2 . add the correct amount of polyvinyl alcohol ( pva ) to the compounding bottle from a 5 % stock solution . 3 . add 50 % of the total batch volume of purified water to the compounding bottle and heat to 90 ° c . while stirring . 4 . add the correct amount of lecithin ( phospholipon 90h ) to the heated pva solution and disperse by stirring . 6 . add the remaining ingredients in the following order , allowing each to disperse / dissolve by stirring before adding the next : benzyl alcohol , glacial acetic acid , sodium acetate , polysorbate 20 , ciprofloxacin hydrochloride , hydrocortisone and sodium chloride . 7 . measure and adjust ph to target ph 4 . 7 ± 0 . 2 with 1n naoh or 1n hcl , if necessary . 1 . tare an appropriate sized compounding bottle ( e . g ., 250 ml ) with stir bar . 2 . add the correct amount of polyvinyl alcohol ( pva ) to the compounding bottle from the 5 % stock solution . 3 . add 50 % of the total batch volume of purified water to the compounding bottle and heat to 90 ° c . while stirring . 4 . add the correct amount of lecithin ( pholspholipon 90h ) to the heated pva solution and disperse by stirring . 1 . in a 100 ml beaker weigh the required amount of polysorbate 20 . add a small amount of purified water to the beaker and begin to stir . 2 . weigh and add the required amount of hydrocortisone ( micronized ) to the beaker . 3 . allow the hydrocortisone to mix well with the polysorbate 20 solution . 1 . once the mixture in part i has cooled to room temperature , add the ingredients in the following order , allowing each to disperse / dissolve before adding the next : benzyl alcohol , glacial acetic acid , sodium acetate , ciprofloxacin hydrochloride and sodium chloride . 4 . measure and adjust ph to 4 . 7 ± 0 . 2 with 1n naoh or 1 n hcl , if necessary . table 1a example ingredient 1 2 3 4 5 6 ciprofloxacin 0 . 35 * 0 . 35 * 0 . 35 * 0 . 35 * 0 . 35 * 0 . 35 * hydrochloride , monohydreate hydrocortisone , 1 . 0 1 . 0 1 . 0 1 . 0 1 . 0 1 . 0 micronized benzyl alcohol 0 . 9 0 . 9 0 . 9 0 . 9 0 . 9 0 . 9 polyvinyl alcohol — 0 . 05 0 . 1 0 . 5 1 . 0 2 . 0 ( airvol 125 ) 99 % hydrolyzed sodium chloride 0 . 9 0 . 9 0 . 9 0 . 9 0 . 9 0 . 9 sodium acetate , trihydrate 0 . 68 0 . 68 0 . 68 0 . 68 0 . 68 0 . 68 glacial acetic acid 0 . 255 0 . 255 0 . 255 0 . 255 0 . 255 0 . 255 lecithin ( phospholipon 90h ) 0 . 15 0 . 15 0 . 15 0 . 15 0 . 15 0 . 15 polysorbate 20 0 . 10 0 . 10 0 . 10 0 . 10 0 . 10 0 . 10 sodium hydroxide ph adjust ph adjust ph adjust ph adjust ph adjust ph adjust and / or hydrochloric acid to 4 . 7 to 4 . 7 to 4 . 7 to 4 . 7 to 4 . 7 to 4 . 7 purified water qs to 100 qs to 100 qs to 100 qs to 100 qs to 100 qs to 100 [ 0053 ] table 1b example ingredient 7 8 9 10 11 ciprofloxacin 0 . 35 * 0 . 35 * 0 . 35 * 0 . 35 * 0 . 35 * hydrochloride , monohydreate hydrocortisone , 1 . 0 1 . 0 1 . 0 1 . 0 1 . 0 micronized benzyl alcohol 0 . 9 0 . 9 0 . 9 0 . 9 0 . 9 polyvinyl alcohol ( airvol — 0 . 05 0 . 1 0 . 5 1 . 0 205s ) 88 % hydrolyzed sodium chloride 0 . 9 0 . 9 0 . 9 0 . 9 0 . 9 sodium acetate , trihydrate 0 . 68 0 . 68 0 . 68 0 . 68 0 . 68 glacial acetic acid 0 . 255 0 . 255 0 . 255 0 . 255 0 . 255 lecithin ( phospholipon 0 . 15 0 . 15 0 . 15 0 . 15 0 . 15 90h ) polysorbate 20 0 . 10 0 . 10 0 . 10 0 . 10 0 . 10 sodium hydroxide and / or ph adjust ph adjust ph adjust ph adjust ph adjust hydrochloric acid to 4 . 7 to 4 . 7 to 4 . 7 to 4 . 7 to 4 . 7 purified water qs to 100 qs to 100 qs to 100 qs to 100 qs to 100 the physical stability of suspension formulations is commonly measured in two ways : rate of settling and resuspendability . rate of settling is assessed by observing the height ( in millimeters ) of the column of sedimentation visible in a sample contained in a cylinder after shaking and then standing for a period of time . larger sedimentation heights indicate less separation with less supernatant liquid and less compaction of the insoluble particles . resuspendability is assessed by measuring the number of inversions ( also called strokes ) required to redisperse sedimentation which forms after a sample stands undisturbed for a period of time . rate of settling results for formulations 1 - 11 are shown in tables 2 a1 and 2 b1 using the following codes ( in order of increasing turbidity ): c : clear supernatant phase , lm : light milky phase ( less dense than homogeneous phase ), h : homogeneous phase ( initial homogeneous phase ), d : dense phase ( more dense than homogeneous phase ), and s : sediment : resuspendability results for the same formulations are shown in tables 2 a2 and 2 b2 . table 2a1 time formulation 1 formulation 2 formulation 3 formulation 4 formulation 5 formulation 6 initial 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 5 min 0 - 4 ml : d 0 - 4 ml : d 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 4 - 10 ml : h 4 - 10 ml : h 15 min 0 - 1 . 6 ml : s 0 - 1 . 9 ml : s 0 - 8 . 8 ml : d 0 - 2 . 5 ml : s 0 - 9 ml : d 0 - 10 ml : h 1 . 6 - 10 ml : lm 1 . 9 - 10 ml : lm 8 . 8 - 10 ml : lm 2 . 5 - 10 ml : lm 9 - 10 ml : lm 30 min 0 - 1 . 5 ml : s 0 - 1 . 8 ml : s 0 - 7 . 5 ml : d 0 - 2 . 4 ml : s 0 - 3 . 3 ml : s 0 - 9 ml : d 1 . 5 - 10 ml : lm 1 . 8 - 10 ml ; lm 7 . 5 - 10 ml : lm 2 . 4 - 10 ml ; lm 3 . 3 - 10 ml : lm 9 - 10 ml : lm 45 min 0 - 1 . 5 ml : s 0 - 1 . 8 ml : s 0 - 7 . 5 ml : d 0 - 2 ml : s 0 - 2 . 5 ml : s 0 - 8 . 5 ml : d 1 . 5 - 9 . 5 ml : lm 1 . 8 - 9 . 3 ml : lm 7 . 5 - 10 ml : lm 2 - 9 . 8 ml : lm 2 . 5 - 10 ml : lm 8 . 5 - 10 ml : lm 9 . 5 - 10 ml : c 9 . 3 - 10 ml : c 9 . 8 - 10 ml ; c 1 hour 0 - 1 . 8 ml : s 0 - 1 . 8 ml : s 0 - 3 ml : s 0 - 1 . 9 ml : s 0 - 2 . 4 ml : s 0 - 4 ml : s 1 . 8 - 8 . 8 ml : lm 1 . 8 - 8 . 8 ml : lm 3 - 10 ml : lm 1 . 9 - 10 ml : lm 2 . 4 - 10 ml : lm 4 - 10 ml : lm 8 . 8 - 10 ml : c 8 . 8 - 10 ml : c 2 hours 0 - 1 . 8 : s 0 - 1 . 8 ml : s 0 - 2 . 5 ml : s 0 - 2 . 5 ml : s 0 - 2 . 5 ml : s 0 - 3 ml : s 1 . 8 - 6 ml : lm 1 . 8 - 7 ml : lm 2 . 5 - 8 . 8 ml : lm 2 . 5 - 10 ml : lm 2 . 5 - loml : lm 3 - 10 ml : lm 6 - 10 ml : c 7 - 10 m : c 8 . 8 - 10 ml : c 3 hours 0 - 2 . 8 ml : s 0 - 5 . 5 ml : s 0 - 2 . 2 ml ; s 0 - 2 ml ; s 0 - 2 ml : s 0 - 2 . 8 : s 2 . 8 - 10 ml : c 5 . 5 - 10 ml : c 2 . 2 - 7 . 9 ml ; d 2 - 10 ml : c 2 - 10 ml : c 2 . 8 - 10 ml : c 7 . 9 - 10 ml : c [ 0055 ] table 2b1 time formulation 1 formulation 7 formulation 8 formulation 9 formulation 10 formulation 11 initial 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 5 min 0 - 4 ml : d 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 4 - 10 ml ; lm 10 min 0 - 1 . 9 ml : s 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 1 . 9 - 10 ml : lm 15 min 0 - 1 . 7 ml : s 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 1 . 7 - 10 ml : lm 20 min 0 - 1 . 7 ml : s 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 1 , 7 - 10 ml : lm 30 min 0 - 1 . 5 ml : s 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 1 . 5 - 10 ml : lm 45 min 0 - 1 . 5 ml : s 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 1 . 5 - 10 ml : lm 1 hour 0 - 1 . 5 ml : s 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 1 . 5 - 10 ml : lm 2 hours 0 - 1 . 6 ml : s 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 0 - 10 ml : h 1 . 6 - 7 . 5 ml : lm 7 . 5 - 10 ml : c 3 hours 0 - 1 . 5 ml : s 0 - 9 . 8 ml : h 0 - 0 . 5 ml : s 0 - 1 ml : s 0 - 1 ml : s 0 - 0 . 5 ml : s 1 . 5 - 5 . 5 ml : lm 9 . 8 - 10 ml : d 0 . 5 - 10 ml : h 1 - 10 ml : h 0 - 2 1 - 10 ml : h 0 . 5 - 10 ml : h 5 . 5 - 10 ml : c 4 hours 0 - 1 . 7 ml : s 0 ‥ 9 . 8 ml : h 0 - 0 . 5 ml : s 0 - 1 ml : s 0 - 1 ml : s 0 - 0 . 5 ml : s 1 . 7 - 4 . 5 ml : lm 9 . 8 - 10 ml : d 0 . 5 - 10 ml : h 1 - 10 ml : h 1 - 10 ml : h 0 . 5 - 10 ml : h 4 . 5 - 10 ml : c 5 hours 0 - 1 . 3 ml : s 0 - 9 . 8 ml : h 0 - 0 . 5 ml : s 0 - 1 ml : s ; 0 - 1 ml : s 0 - 0 . 5 ml : s 1 . 3 - 2 . 5 ml : lm 9 . 8 - 10 ml : d 0 . 5 - 10 ml : h 1 - 10 ml : h 1 - 10 ml : h 0 . 5 - 10 ml : h 2 . 5 - 10 ml : c 6 hours 0 - 2 ml : s 0 - 1 . 5 ml : s 0 - 0 . 5 ml : s 0 - 0 . 5 ml s ; 0 - 0 . 5 ml : s 0 - 0 . 5 ml : s 2 - 10 ml : c 1 . 5 - 10 ml : lm 0 . 5 - 10 ml : lm 0 . 5 - 10 ml lm 0 . 5 - 10 ml : lm 0 . 5 - 10 ml : lm 1 day 0 - 1 . 8 ml : 5 0 - 1 ml : 5 0 - 0 . 5 ml : s 0 - 0 . 5 ml s ; 0 - 0 . 5 ml : s 0 - 0 . 5 ml : s 1 . 8 - 10 ml : c 1 - 9 . 7 ml : lm 0 . 5 - 9 . 7 ml : lm 0 . 5 - 9 . 7 ml : lm 0 . 5 - 9 . 7 ml : lm 0 . 5 - 9 . 7 ml : lm 9 . 7 - 10 ml : c 9 . 7 - 10 ml : c 9 . 7 - 10 ml : c 9 . 7 - 10 ml : c 9 . 7 - 10 ml : c 4 day 0 - 1 . 6 ml : s 0 - 0 . 6 ml : s 0 - 0 . 5 ml : s 0 - 0 . 5 ml : s 0 - 0 . 4 ml : s 0 - 0 . 3 ml : s 1 . 6 - 10 ml : c 0 . 6 - 9 . 6 ml : lm 0 . 5 - 9 . 5 ml : lm 0 . 5 - 9 . 8 ml : lm 0 . 4 - 9 . 7 ml : lm 0 . 3 - 9 . 8 ml : lm 9 . 6 - 10 ml : c 9 . 5 - 10 ml : c 9 . 8 - 10 ml : c 9 . 7 - 10 ml : c 9 . 8 - 10 ml : c the rate of settling results are summarized in fig1 - 6 . fig1 and 2 each compares two different grades of pva after standing for a specified time . fig1 compares these grades at a concentration 0 . 05 % after standing for 2 hrs . fig2 compares these grades at a concentration of 2 % after standing for 45 minutes . fig3 and 4 compare two grades of pva at a fixed concentration ( 0 . 05 %), with varying time ( 0 - 180 minutes ). fig5 and 6 compare two grades of pva at a fixed time ( 1 hr ), with varying concentration ( 0 - 2 %). resuspendability results for formulations 1 - 11 are shown in tables 2a2 and 2b2 . each of the eleven formulations were centrifuged at 500 rpm for 30 minutes using iec centra - 7 centrifuge , then resuspended by gentle , manual inversion technique into a homogenous suspension . the number of manual inversions required to fully resuspend each formulation is presented in tables 2 a2 and 2 b2 . in order to confirm that there was no significant difference in the rate of settling results attributable to the difference in methods a and b , formulation # 6 was prepared by both methods . the rate of settling results ( using the same codes used for tables 2a1 and 2b1 ) are shown in table 3 below . two grades of polyvinyl alcohol ( 88 % vs . 99 % hydrolyzed ) were evaluated for the amount of residue ( film thickness ) they leave upon drying . for topical otic products , the smaller amount of residue ( the thinner the film ) left upon drying , the less likely a patient is to experience discomfort during use . separate 2 % solutions of airvol 125 ( 99 % hydrolyzed ) and airvol 205s ( 88 % hydrolyzed ) polyvinyl alcohol were analyzed as follows . the results are shown in table 4 . using a 10 - 100 ( eppindorf automatic pipette , 4 - 5 100 μl drops of each sample were placed into 100 × 20 mm culture dishes and allowed to dry overnight on the benchtop . 1 . one of the dried drops from the culture dish was removed using a scalpel to separate it from the bottom of the dish . 2 . along its diameter , the drop was cut in half using a very thin razor blade to expose a cross - section . 3 . one of the resulting sections was placed between two microscope slides with the cross - section of the drop exposed at the top of the slides . 4 . the two microscope slides were bound together using rubber bands . 5 . using modeling clay , the slides were placed in a position under the microscope as to view the cross - section of the sample 6 . using optimas software , measured the thickness of the film at 100 × magnification was measured at the edge of the cross - section and at the center of the cross - section . films of airvol 125 and airvol 205s were added to 0 . 1 - 0 . 2 ml of phosphate buffered saline and the commercially available otic solutions identified below to determine whether the films would dissolve . the results are shown in table 5 , where “ dnd ” means that the film did not dissolve and “ rd ” means that the film readily dissolved . the invention has been described by reference to certain preferred embodiments ; however , it should be understood that it may be embodied in other specific forms or variations thereof without departing from its spirit or essential characteristics . the embodiments described above are therefore considered to be illustrative in all respects and not restrictive , the scope of the invention being indicated by the appended claims rather than by the foregoing description .
this invention is directed toward a topical composition comprising ciprofloxacin and hydrocortisone , where the composition contains a specific grade of polyvinyl alcohol as a viscosity augmenter . the specified grade of polyvinyl alcohol is 85 - 90 % hydrolyzed polyvinyl alcohol .