AU3935200A - Method and composition for cleaning and disinfecting contact lenses - Google Patents

Description

S&FRef: 120571D1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Bausch Lomb Incorporated One Lincoln First Square P.O. Box 54 Rochester New York 14601-0054 United States of America George E. Minno, David W. Proud, Mary F. Mowret- McKee Spruson Ferguson St Martins Tower 31 Market Street Sydney NSW 2000 Method and Composition for Cleaning and Disinfecting Contact Lenses The following statement is a full description of this invention, including the best method of performing it known to me/us:- OP Australia Documents rece", n r l: 7 JUN 2000 Batch No: 5845c METHOD AND COMPOSITION FOR CLEARING AND DISINFTCTING CONTACT LENSES BACKGROUND OF THE INVENTION Field of the Invention S This invention relates to a method for cleaning and disinfecting contact lenses and a composition for the same.

More specifically, the present invention is directed to a method for simultaneously cleaning and disinfecting contact lenses by contacting the lenses with an aqueous system containing an antimicrobial agent and a proteolytic enzyme. A composition for simultaneously cleaning and disinfecting the lenses is also provided.

Description of Art In the normal course of wearing contact lenses, tear film 5 and debris consisting of proteinaceous, oily, sebaceous, and related organic matter have a tendency to deposit and build up on lens surfaces. As part of the routine care regimen, contact lenses must be cleaned to remove these tear film deposits and debris. If these deposits are not properly removed, both the 2 0 wettability and optical clarity of the lenses is substantially reduced causing discomfort for the wearer.

Further, contact lenses, especially those made from hydrophilic materials, must be continuously disinfected to kill any harmful microorganisms that may be present or grow on the Z lenses. A number of methods for disinfecting contact lenses have been used such as the use of high temperatures, the use of oxidative chemicals, and the use of antimicrobial agents.

However, current disinfecting solutions do not exhibit significant cleaning ability for the removal of proteinaceous material.

Conventionally, the cleaning of contact lenses is accomplished with one or both of two general classes of cleaners. Surfactant cleaners, generally known as "daily cleaners" because of their recommended daily use, are effective for the removal of most carbohydrate and lipid derived matter. However, they are not as effective for the removal of proteinaceous matter such as lysozyme. Typically, proteolytic enzymes derived from plant, animal, and microbial sources are used to remove the proteinaceous deposits. These LM "enzyme" cleaners are recommended for weekly use and are conventionally employed by dissolving enzyme tablets in suitable aqueous solutions.

The process of cleaning and disinfecting contact lenses with enzyme cleaners (as well as daily cleaners) involves two steps. The first step consists of the cleaning phase whereby lenses are conventionally soaked in an enzyme cleaning solution at ambient temperature conditions, i.e, cold soaking for a period of up to 12 hours, to achieve effective removal *of proteinaceous deposits. At the conclusion of the cleaning 2.0 step, the lenses are separately disinfected. Disinfection involves contacting the lenses with a solution containing either an oxidative chemical or an antimicrobial agent at ambient temperatures or exposing the lenses to elevated temperatures for specified periods of time. The latter 2 disinfection technique requires specific electrical disinfecting apparatus.

New methods have been developed which can remove a o ~proteinaceous material from contact lenses while disinfecting the lenses. For example, U.S. Patent 4,614,549 discloses a single-step method of cleaning and disinfecting contact lenses in aqueous solutions of proteolytic enzymes at temperatures of between 60 0 C and 100°C. This method requires the use of electrical disinfecting apparatus and elevated temperatures.

2 U.S. Patent Re. 32,672 discloses a method which immerses the lenses in a solution containing peroxide and a peroxide-active enzyme. However, this method requires an additional step for the neutralization of the residual peroxide prior to inserting the lens into the eye.

In order to develop an improved simultaneous cleaning and disinfecting method that does not require neutralization of any oxidative chemical, proteolytic enzymes in tablet form were tested in combination with a disinfecting solution \0 containing hexamethylene biguanide polymers as the antimicrobial agent at ambient conditions. However, subsequent microbicidal efficacy studies revealed that the antimicrobial agent was rendered less effective for killing certain microorganisms during these initial studies.

I However, it has now been discovered that the disinfecting ability of antimicrobial agents, particularly at ambient temperatures, is most effective under conditions of suitable osmolality for the agent employed. When the osmotic level of the solution is too high, the antimicrobial agents are 0 rendered less effective for killing certain microorganisms.

Thus, according to this invention, proteolytic enzymes can be used in combination with antimicrobial agents to simultaneously clean and disinfect contact lenses. Under ambient temperatures, the disinfection has been found to be most effective at suitable osmotic conditions. The present invention provides a less complex and more convenient regimen for cleaning and disinfecting contact lenses without the need for a separate neutralizing step or electrical disinfecting apparatus.

3 Summary of the Invention There is disclosed herein a method for simultaneously cleaning and disinfecting contact lenses, comprising contactibng the lenses with an aqueous system containing a disinfecting amount of an antimicrobial agent selected from the group consisting of polymeric quanternary ammonium salts used in ophthalmic applications and biguanides, in absence of thimerosal, and an effective amount of a proteolytic enzyme for a time sufficient to simultaneously clean and disinfect the lenses and wherein the osmotic value of said aqueous system is adjusted to a level which does not substantially inhibit the activity of the said antimicrobial agent.

There is also disclosed a method of simultaneously cleaning and disinfecting contact lenses o1 comprising the steps of: dissolving an effective amount of a proteolytic enzyme in a disinfecting solution containing, as the antimicrobial agent, from about 0.00001 to about 0.5 percent by weight/volume of a non-oxidative chemical selected from the group consisting of polymeric quaternary ammonium salts used in ophthalmic applications and biguanides and from about 0.01 to about 2.5 percent by weight/volume of a buffering agent and sufficient tonicity adjusting agent to provide said solution with a final osmotic value of less than about 800mOsm./kg. water and contacting said lenses with said solution for a period of time sufficient to simultaneously clean and disinfect said lenses in the absence of thimerosal.

i There is further disclosed an improved method for cleaning and disinfecting contact lenses with 20 proteolytic enzymes and antimicrobial agents in the absence of thimerosal, the improvement comprising contacting the lenses with an aqueous system containing an effective amount of said enzyme and a disinfecting amount of said antimicrobial agent, said antimicrobial agent being selected from the group consisting of polymeric quaternary ammonium salts used in ophthalmic applications and biguanides, and maintaining the osmotic value of the system, by the addition of a tonicity adjusting agent, at a level which does not substantially inhibit the activity of the antimicrobial agent.

Detailed Description of the Invention The present invention can be used with all contact lenses such as conventional hard, soft, rigid gas permeable, and silicone lenses but is preferably employed with soft lenses such as those commonly referred to as hydrogel lenses prepared from monomers such as hydroxyethylmethacrylate, hydroxyethylmethyl methacrylate, vinylpyrrolidone, glycerolmethacrylate, metacrylic acid or acid esters and the like. Hydrogel lenses typically absorb significant amounts of water such as from 4 to 80 percent by weight.

The compositions employed herein for the cleaning and disinfecting of contact lenses are composed of at least water, one or more proteolytic enzymes, and one or more antimicrobial agents.

Generally, these cleaning and disinfecting systems are prepared by mixing two components, the [R:\LIBZ]05209.doc:BAV enzyme and a disinfecting solution containing the antimicrobial agents. However, other methods of combining the active components as well as off the shelf compositions containing all of the active components are contemplated as being within the scope of this invention.

A wide variety of proteolytic enzymes are useful in the present invention such as those derived from plant, animal, and microbial sources. The separation and purification of these enzymes is well known to those skilled in the art with many of these enzymes being commercially available.

Moreover, it is anticipated that many of the enzymes can be prepared from new techniques being developed such as those using recombinant DNA techniques and proteolytic enzymes prepared by these techniques are contemplated to be within the scope of the present invention.

1o The proteolytic enzymes used herein must have at least a partial capability to hydrolyse peptide-amide bonds which reduces the proteinaceous material to smaller water-soluble subunits.

Typically, these enzymes will exhibit some lipolytic, amylolytic or related activities associated with the proteolytic activity and may be neutral, acidic or alkaline. In addition, separate lipases or carbohydrases may by used in combination with the proteolytic enzymes.

Examples of suitable proteolytic enzymes include but are not limited to pancreatin, trypsin, chymotrypsin, collagenase, papain, bromelain, aminopeptidase, Aspergillo peptidase, pronase E (from S. graseus) and dispase (from Bacillus polymyxa). The preferred group of proteolytic enzymes are the microbial derived enzymes such as those derived from Bacillus, Streptomyces, and Aspergillus *microorganisms. Most preferred are the Bacillus derived alkaline proteases generically called subtilisin 20 enzymes. The subtilisin enzymes include both sub-classes, subtilisin A and subtilisin B. Microbial derived enzymes are disclosed in U.S. Patent 4,690,773 incorporated herein by reference.

**o [R:\LIBZ]05209.doc:BAV The present invention employs an effective amount of enzyme to clean the lenses. An effective amount is that which removes a substantial portion of the proteinaceous deposits which occur during normal wear in a reasonable time. The precise amount of enzyme required to make an effective cleaner will depend on several factors including the activity of the enzyme, the purity of the enzyme, the amount of proteinaceous matter deposited on the lenses, the desired soaking period, the specific type of lenses, as well as other factors.

It should be appreciated to one skilled in the art, that the enzyme concentrations useful herein are adjusted depending upon the time allowed for removing the proteinaceous material, the other components in the solutions and the factors previously mentioned. Typically, when the enzyme is provided i> in solid form, it will be present in amounts from about 0.01 to about 200 milligrams.

Enzyme activity is generally pH dependent and there will be a particular pH range in which any particular enzyme will :function best. However, the determination of an optimum pH 0Z range can readily be determined by known techniques by those skilled in the art. It is preferred that the enzyme be selected to have substantial activity at a pH between about 6.5 and about 4 The enzyme may be employed in liquid or solid form usually 2 in combination with additional components. Preferably, the enzymes are provided in solid form such as tablets or powders which are mixed with the aqueous solutions prior to use.

Additional components may be added to or incorporated into the enzyme which do not substantially decrease the activity of the enzyme. For example, components such as effervescing agents, stabilizers, buffering agents, chelating and/or sequestering agents, coloring agents, tonicity adjusting 6 agents, surfactants and the like can be employed. In addition, binders, lubricants, carriers, and other excipients normally used in producing tablets may be incorporated into the enzyme when tablets are employed.

Examples of suitable buffering agents which may be incorporated into the enzyme include, but are not limited to, alkali metal salts such as potassium or sodium carbonates, acetates, borates, phosphates, citrates and hydroxides, and weak acids such as acetic and boric acids. Preferred buffering agents are alkali metal borates such as sodium or potassium borates. Additionally, other pH adjusting agents may be employed such as inorganic acids. For example, hydrogen chloride may be employed in concentrations suitable for ophthalmic uses. Generally, buffering agents are present IS in amounts from about 0.01 to about 2.5 percent by weight/volume Effervescing agents are typically employed when the enzyme is provided in solid form. Examples of suitable effervescing agents include, but are not limited to, tartaric or citric .0 acid used in combination with a suitable alkali metal salt such as sodium carbonate.

The disinfecting solutions used with the present invention may contain any of the above-mentioned enzyme components as well as other components but typically will contain water, the f4 antimicrobial agent, one or more of a suitable buffering agent, chelating and/or sequestering agent, tonicity adjusting ee agent, and surfactant.

The tonicity adjusting agent which may be a component of the disinfecting solution and may optionally be incorporated into the enzyme is employed to adjust the osmotic value of the final cleaning and disinfecting solution to more closely 7 resemble that of human tears and to maintain a suitable level for optimum activity by the antimicrobial agent. Suitable tonicity adjusting agents include, but are not limited to, sodium and potassium chloride, dextrose, calcium and magnesium chloride, the buffering agents listed above and combinations thereof. The tonicity adjusting agents are individually used in amounts ranging from about 0.01 to 2.5% and preferably, from about 0.5 to about 1.5% Most preferably, the tonicity agent will be employed in an amount 0 to provide a final osmotic value of the cleaning and disinfecting solutions of less than about 800 millosmoles/kilogram water (m0sm./kg. water) Suitable surfactants can be either cationic, anionic, nonionic or amphoteric. Preferred surfactants are neutral or IS nonionic surfactants which may be present in amounts up to Examples of suitable surfactants include, but are not limited to, polyethylene glycol esters of fatty acids, polyoxypropylene ethers of C 12

-C

18 alkanes and polyoxyethylene, polyoxypropylene block copolymers of ethylene !0 diamine poloxamine).

a Examples of preferred chelating agents include Ethylenediaminetetraacetic acid (EDTA) and its salts (disodium) which are normally employed in amounts from about 0.025 to about 2.0% Other known chelating (or 3S sequestering agents) such as certain polyvinyl alcohols can also be employed.

The disinfecting solutions used with this invention will contain a disinfecting amount of one or more antimicrobial agents which are compatible with and do not precipitate in the presence of the enzymes. As used herein, antimicrobial agents are defined as non-oxidative organic chemicals which derive their antimicrobial activity through a chemical or 8 physicochnemica interaction with the organisms. Suitable antimicrobial agents are those generally employed in ophthalmic applications and include, but are not limited to, quaternary ammonium salts used in ophthalmic applications such as poly[(dimethyliminio)-2-butene-l,4-diyl chloride), c1 [4-tris(2-hydroxyethyl) armonio]-2-butenyl-w-tris (2hydroxyethyl)ammonio)dichloride (chemical registry number 75345-27-6) generally available as polyquaternium 10 from ONYX Corporation and benzalkonium halides, and biguanides such as \b salts of alexidine, alexidine free base, salts of chlorhexidine, hexamethylene biguanides and their polymers.

The salts of alexidine and chlorhexidine can be either organic or inorganic and are typically gluconates, nitrates, acetates, phosphates, sulphates, halides and the like. Preferred 1 antimicrobial agents are the biguanides with hexamethylene biguanides, their polymers and water-soluble salts being most preferred. Generally, the hexamethylene biguanide polymers, also referred to as pclyaminopropyl biguanide (PAPB), have molecular weights of up to about 100,000. Such compounds are 0 known and are disclosed in U.S. 4 ,758,595 which is incorporated herein by reference.

A disinfecting amount of antimicrobial agent is an amount which will at least partially reduce the microorganism population in the formulations employed. Preferably, a AS disinfecting amount is that which will reduce the microbial burden by two log orders in four hours and more preferably by one log order in one hour. Most preferably, a disinfecting amount is an amount which will eliminate the microbial burden on a contact lens when used in regimen for the recommended soaking time (FDA Chemical Disinfection Efficacy Test-July, 1985 Contact Lens Solution Draft Guidelines). Typically, such agents are present in concentrations ranging from about 0.00001 to about 0.5% and more preferably, from about 0.00003 to about 0.05% 9 As mentioned above, it has been found that the antimicrobial agents at simulated commercial concentrations are rendered less effective in environments having high osmotic values, generally above about 800 m0sm./kg. water at typical commercial concentrations (generally less than about 0.05% This is a particularly important discovery since it is common in the industry to add bulking agents to the active enzyme when used in tablet or powder form. These bulking agents usually increase the osmotic values of the O0 cleaning solutions, often significantly reducing the antimicrobial activity. Further, the various components discussed above, as well as others, may also raise the osrolality of the final formulation.

Moreover, it should also be understood that the particular i 'osmotic value rendering any given antimicrobial agent .neffective will vary from agent to agent. The determination of the suitable osmotic range for any particular antimicrobial agent can be easily determined by routine expermentat ion by o e in.

one skilled in the art. However, a preferred range of osmotic values has been found to be less than about 800 m0sm./kg.

20 water and more preferable about 200 to about 600 mOsm./kc.

water at antimicrobial agent concentrations of less than about 0.05% During practice of this invention, the enzyme formulation, either in solid or liquid form, is typically dissolved in a predetermined amount of disinfecting solution which may be a t" isotonic or hypotonic, to obtain a cleaning and disinfecting solution having the proper osmotic value. This solution is 000 then contacted with lenses at ambient temperatures for a sufficient time to clean and disinfect.

In a preferred embodiment of the invention, an enzyme tablet is dissolved in an aqueous disinfecting solution containing a biguanide as the antimicrobial agent in order to 10 prepare the cleaning and disinfecting solution. The lenses are then contacted with the cleaning and disinfecting solution, preferably by being immersed therein, and remain in contact with the solution for a sufficient period of time to disinfect the lenses. An effective amount of enzyme agent is used such that the time sufficient to disinfect will also be sufficient to substantially remove the proteinaceous deposits. Typically, the cleaning and disinfecting will take less than about eight hours with about 1 to about 4 hours being preferred. Advantageously, the lenses can be removed from the solution and placed directly into the eye without the need for a separate neutralizing step. Preferably, the lenses are rinsed with a suitable isotonic aqueous solution prior to insertion into the eye.

S The following detailed examples are presented to illustrate the present invention.

.imulate 1-36 In order to study the antieamcrobia efficacy of ete ch compositions of the present invention, several aqueous solutions were prepared and evaluated for the log kill rate of Serratia marcescens.

Aqueous solutions were prepared having compositions which S simulate conium ercal disinfecting solutions. All percentages indicated throughout these examples are in weight/volume aS Each composition had 0.85% boric acid, 0.09% sodium borate, Tetronic® 1107 (a poloxamine surfactant purchased from BASF Corporation), simulated commercial concentrations of ale= i d i n e dihycdrochloride, chiorhezidine cgluconate, PAPB, polyquaterni n (purchased from ONYX Corporation), and benzalkonium chloride as the antimicrobial agent respectively and0.005% of a proteolytic enzyme (subtilisin-A enzyme 11 purchased from NOVO Laboratories, Inc.). The osmolality was varied using sodium chloride as the tonicity adjusting agent.

Two separate solutions were tested for each composition.

The compositions are shown in Table I.

The microbicidal activity of the above solutions were tested in duplicate by exposing Serratia marcescens at about x 10 6 to about 1.0 x 10 7 colony forming units per milliliter (CFU/ml.) to 10 ml. of each solution at room temperature for 1 hour and 4 hour time intervals. An aliquot of each inoculated sample was removed at 1 and 4 hours and diluted in a neutralizing broth (Dey-Engley) and plated with neutralizing agar. The agar plates were incubated for two days and plate counts were determined to calculate reduction in CFU/ml. for the organism. The calculated log order IS reductions are shown in Table I.

As can be seen from Table I the log order reductions of the Svarious antimicrobial agents tested were significantly reduced at high osmotic levels.

e o 12 TABLE I

DISIRFECTING

EXAMPLE DISINFECTING AGENT SODIUM MEASURED LOG REDUCTION CHLORIDE OSMOLALITY S. MARCESCENS (mOsm/kg 1 Hour 4 Hours vater) Alexidine 1.0 ppm Alexidine 1.0 ppm Ale-xidine 1.0 ppm Alexidine 1.0 ppm Alexidine 1.0 ppm Alexidine 1.0 ppm Alexidine 1.0 ppm Alexidirie 1.0 ppm Alexidine 1.0 ppm Alexidine 1.0 ppm Alexidine 1.0 ppm Alexidine 1.0 ppm Chiorhex 100 ppm Chiorhex 100 ppm Cbiorhex 100 ppm Chiorhex 100 ppm Chiorhex 100 ppm Chiorhex 100 ppm Chiorhex 100 ppm Chiorhex 100 ppm 0.20 0.20 0.53 0.53 0.85 0.85 1.15 1.15 1.47 1.47 2.09 2.09 0.20 0.20 0.53 0.53 0.85 0.85 1.15 1.15 2.6 2.6 1.2 1.2 0.5 0.6 0.2 0.0 3.4 3.4 1.6 1. 1 1. 1 4* 800 800 202 202 306 306 402 402 501 501 5 >4.5 >4.5 >4.5 2.0 2.0 1.0 1.4 13 TKBLE I DISINFECTING (Continued) EXAMPLE DISINTECTING AGENT SODIUM. MEASURED LOG REDUCTION CifLORIDE OSMOLAiTY S. ARCESCES 7 (mOsm/kg 1 Hour 4 Hours water) 11A

B

12.A

B

13A

B

Chlorhex 100 ppm Chiorhex 100 ppm Chlorhex 100 ppm Chiorhex 100 ppm PAPB 1.0 ppm PAPB 1.0 ppm 16A

B

S A 19 A

B

20A

B

PAPE 1.0 ppm PAPB 1.0 ppm PAB 1.0 ppm PAPB 1.0 ppm PAPB 1.0 ppm PAPB 1.0 ppm ?APB 2.0 ppm PAPB 1.0 ppm 1.47 1.47 2 .09 2 .09 0.20 0.20 0.53 0.53 0.85 0.85 1.15 1.15 1.47 1.47 2 09 2 09 0.20 0.20 0.53 0.53 1.0 1.0 301 301 402 402 501 501 601 601 801 801 200 200 303 303 1.6 1.4 >4.5 4.5 4.2 4.3 3.0 2.8 2.7 2.7 1.9 )4 2.1 0.3 0.2 3.9 4.2 PAPBD 1.0 ppm PAPE 1.0 ppm Polyquatermum1 100 ppm Polyquaterr-iunil 100 ppm Polyquaternlrl1 100 ppm Polyquatern.:JLrn1 100 ppm 2.4 2 .3 3.9 4.2 14 TABLE I DISlF{TTCTINqG (Cortinued) E YJ\PW jL E D1SINFTECTING AGENTT SODIUM~ ?f.AS U UD LOG REDUCTION CL-EL0R1 DE OSMiOLALI TY S. KkcEscENs S(W/v) (mOsm/kg I Hour '4 hours wa ter) 21A

B

2 2A

B

2 3A

B

24A

B

Poly quetrerii 1 100 ppm Po2.yquater-r~n 1 100 ppm PolyquaternDun 1 100 ppm Polvqup.terum 1 100 ppm PolyQuaternixn 1 2.00 ppm PolyQuaternun 1 100 ppm PolyquaternuLm 2 100 ppm ?olyquaterIn= 1 200 ppm Benzalkonium Chloride 2.00 ppm Benzalkoni= Chlorijde 100 ppm Benz&1konix= C'hlcr.-de 200 ppm, Bernzalkop.' Chloride 1,00 ppm a.

a a.

a. a.

a

B

26 A

B

0. 85 0.85 1 .15 is.1 1.4 1.

2 .09 2 .09 0. 20 0. 0 .5 3 0. 53 0 .85 0.8S5 .5 3 .1 2.6 2.1 2. 1 .2 &02 802 >4 .5 )4 .5 >4.5 Benzalkoni=, 2 00 ppm Benz a 2kon !a 200 ppm B en F-1kon i U 200 ppm Benz k on iu-- 100 ppm Benzalkonl= 100 ppmc Becn.za ikon i u~m 2.00 ppm Chl1o :-16e Chlo:-ide Chloride Ch 1rid e Ch 1 o r i d e C-P 1 o r 16e 499 .5 )4 .5 )4 )4 .5 1 47 15 TkAB LE I DISINFECTING (Continued) EX)J1?LE DISINTFECTING AGEbiT SOD IUM CfILOR ID E x (W/V) M{EAS URED OS 10L L IT Y (M 0 M /kg8 water) LOG REDUCTION S ?LkRCESCENS 1 flour 4 Hours Benzalkoniun Chloride 100 ppm Benzalkonium Chloride 100 ppm PAPB 0. 5 ppm PAPE 0.5 ppm PAPE 0.5 ppm PAPB 0.5 ppm PAPB 0.5 ppm PAFE 0.5 ppm PAPB 0.5 ppm PAPB 0.5 ppm PAPB 0.5 ppm PAB 0.5 ppm PAPB 0.5 ppm PAPB 0.5 ppm 2.09 2.09 0.20 0.20 0.53 0.53 0.85 0.85 1. 15 1 5 1.47 1.47 2 .09 2.09 801 801 204 204 309 309 402 402 509 509 607 607 806 806 2 .7 2.9 >4 0.1 .0.0 1.0 1 .1 0.1 0.2 1 1 0.0 0.0 -0 1 0.0 0.2 0.3 2 .7 2. 7 0.2 0.2 1 i 0.0 0.0 a. a a. a a a a a 16 Bxam~2e 7 in order to Study' the cleaning eff icacy of the present invention, several Solutions were prepared and evaluated for removal of lysozy-me deposits from contact lenses.

T-he percent light transmission through ten new Bausch Lor-mb Sof lens(D (pa lymacon) Contact Lenses was read through a uv/vis spectrophotometer at 500 and 280 nanometers An average transmission value was obtained (Tn) which was used below to calculate percent protein removal. An aqueous 1Q solution was prepared containing 0.7% iNaCl, 0.22% sodium bicarbonate, 0.17% potassium chloride, 0.0005% calcium chloride and .0.15% lysozyme (31 crystallized from egg white).

Five lenses were soaked in the lysozyme solution and heated for about 1 hour at about 90'C. After heating, the lenses removed, finger rubbed an6 rinsed with isotonic saline solution to remove any nonbound lvsozN-me on the lenses.Th percent light transmission was tak.en at 280 and 500 nm (76).

*e mi ofa.ceu :ne lenses were then submerged in 10m.ofa ueu s o Iu zon c o n t a iPn c 0 .0 0 5% o f sx-,b i Ii sin- -A o r o teo I .t ic e n z e 0 (rom NOVO Laboratories Inc.) and a I eidinC eTvrclrie(.

at osmotic values adjusted to 300 and 600 m0sn. /ko water.

The l.enses rema2ined in the solution for _1 hour- at ambient temoerature. The lenses were removed, rubbedl and rinsed in an acueous isotonic solution and soaked -In the aqueous isotonic ~solution for an aocitiona-l 15 minutes. The percent Iioht transmission was taken at 280 and $00 rn (Te).

The ab-ove tr -ansmi ssI on re acincs wer--e p2 aced into the folw ino e cu atiLo n a t e ac h r eac ino 2 80 a no: ~00 na) t o determine the percent of lysozvm..e removec: 17 protein lysozyme removed (Tn-Td) (Tn-Te) (Tn-Td) The protein removed at 500 nm (the visual range of light) and at 280 nm (specific for protein) is shown in Table II.

Examples 38-41 The procedure of Example 37 was repeated except that chlorhexidine gluconate (100 ppm), PAPB (0.5 ppm), polyquaternium 10 (100 ppm), and benzalkonium chloride (100 ppm) were substituted for alexidine dihydrochloride, respectively. The results are shown in Table II.

ib As can be seen from Table II, the present invention removes proteinaceous deposits from contact lenses. It should be mentioned, that the lysozyme deposition technique used herein results in much more severe protein deposition than occurs during normal wear.

It is to be understood that the subject invention is not limited by the above examples which have been provided merely to demonstrate operability and which do not purport to be wholly definitive of the scope of this invention. The scope of this invention shall include equivalent embodiments, 10 modifications, and variations that fall within the scope of the attached claims.

18 TABLE I I CLEAN ING PRESERVATIVE OSMOLALITY PROTEIN REMOVED PROTEIN REMOVED (mOsm/kg. water) (500 nin) (280 nm) 37. alexidine 1 2 3 4 Average 300 93.4 76.8 75.0 92.5 57.4 79.0 86.8 45.8 16.7 70.3 54.9 49.5 35.3 33.3 42.4 35.8 39.3 43.6 11.2 25.0 33.3 2.9 23.2 600 Average 38. chlorhexidine 2 3 4 Average 77.1 25.0 64.9 78.9 64.3 62.0 71.0 53.8 11.1 79.3 40.0 51.0 Average No protein removal obser-ved Chlorhexidine interferes with light transmission at 280 un 19 TKBLE I I CLFAIUNG (Continued) PRESERVATIVE OSMOLALITY PROTEIN REM0V'ED PROTEIN REMOVED (mosrn/kg. water) (500 nm) (280 nm) 39. PAPB 300 2 3 4 Average 1 2 3 4 Average 40. polyquaternium 1 64.8 63.9 54.4 41.0 15.8 48.0 50.0 68.0 31.2 66.7 66.0 56.4 48.4 45.1 29.1 26.7 7 .3 31.3 32.9 27 .8 31.1 66.4 45.9 40.8 a a a a..

a a a.

300 Average 1 2 3 4 5 Average 95.9 70.0 85.8 50.9 34.1 67.3 87.5 75.0 89.5 90.2 88.9 86.2 71 .2 42.2 56.7 21.5 26.2 43.6 47 .2 45.2 27 .1 60.7 30.9 42.2 600 20 TABLE I I CLEARING (Continued) PRESERVATIVE OSMOLALITY (mosm/kg. water) %PROTEIN REMOVED (500 nin) %PROTEIN REMOVED (280 rim) 41. benzalkonium chloride 1 2 3 4 Average 1 2 3 4 Average 300 17.4 37 .5 46.2 44.0 48.0 38 .6 50.0 36.4 59.1 8.4 59.4 42.7 39.5 27.1 37.2 2? .2 35.4 33.3 44 .1 39.8 21.4 20.6 29.8 31.1 a. a a a 21

Claims (20)

1. A method for simultaneously cleaning and disinfecting contact lenses, comprising contacting the lenses with an aqueous system containing a disinfecting amount of an antimicrobial agent selected from the group consisting of polymeric quanternary ammonium salts used in s ophthalmic applications and biguanides, in absence of thimerosal, and an effective amount of a proteolytic enzyme for a time sufficient to simultaneously clean and disinfect the lenses and wherein the osmotic value of said aqueous system is adjusted to a level which does not substantially inhibit the activity of the said antimicrobial agent.

2. The method of claim 1 wherein said antimicrobial agent and said proteolytic enzyme are o in an aqueous solution.

3. The method of claim 1 or 2 wherein said antimicrobial agent and said proteolytic enzyme are contacted with the lenses at ambient temperatures.

4. The method of any one of claims 1 to 3 wherein the osmotic value is less than about 800 mOsm./kg. water.

5. The method of any one of claims 1 to 4 wherein said antimicrobial agent is a biguanide.

6. The method of claim 5 wherein said biguanide is hexamethylene biguanide polymer having molecular weights of up to about 100,000.

7. The method of any one of claims 1 to 6 wherein said osmotic value is from about 200 to about 600mOsm./kg. water. 20

8. The method of any one of claims 1 to 7 wherein said proteolytic enzyme is in a powder or tablet form and is dissolved in a disinfecting solution containing water and said antimicrobial agent to prepare said aqueous system.

9. The method of any one of claims 1 to 8 wherein said proteolytic enzyme is a subtilisin enzyme.

10. The method of claim 3 wherein said aqueous solution additionally contains a buffering agent.

11. The method of claim 3 wherein said aqueous solution additionally contains a surfactant. *0'6

12. A method of simultaneously cleaning and disinfecting contact lenses comprising the steps of: dissolving an effective amount of a proteolytic enzyme in a disinfecting solution containing, as the antimicrobial agent, from about 0.00001 to about 0.5 percent by weight/volume of a non-oxidative chemical selected from the group consisting of polymeric quaternary ammonium salts used in ophthalmic applications and biguanides and from about 0.01 to about 2.5 percent by weight/volume of a buffering agent and sufficient tonicity adjusting agent to provide said solution with a final osmotic 3 value of less than about 800mOsm./kg. water and [R:\LIBZ]05209.doc:BAV 23 contacting said lenses with said solution for a period of time sufficient to simultaneously clean and disinfect said lenses in the absence of thimerosal.

13. An improved method for cleaning and disinfecting contact lenses with proteolytic enzymes and antimicrobial agents in the absence of thimerosal, the improvement comprising s contacting the lenses with an aqueous system containing an effective amount of said enzyme and a disinfecting amount of said antimicrobial agent, said antimicrobial agent being selected from the group consisting of polymeric quaternary ammonium salts used in ophthalmic applications and biguanides, and maintaining the osmotic value of the system, by the addition of a tonicity adjusting agent, at a level which does not substantially inhibit the activity of the antimicrobial agent. o

14. The method of claim 13 wherein the osmotic value is less than about 800 mOsm./kg. water.

The method of claim 13 or claim 14 wherein said composition is prepared by mixing said proteolytic enzyme in a disinfecting solution containing said antimicrobial agent.

16. The method of claim 15 wherein said anitmicrobial agent is present in an amount ranging from about 0.00001 to about 0.5 percent by weight/volume.

17. The method of claim 16 wherein said proteolytic enzyme is in tablet or powder form.

18. The method of claim 17 wherein said proteolytic enzyme is a subtilisin enzyme. S"

19. The method of claim 18 wherein said antimicrobial agent is a biguanide.

20. The method of claim 19 wherein said biguanide is a polymer of hexamethylene 20 biguanide. Dated 7 June, 2000 Bausch Lomb Incorporated C Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON *o ole [R:\LIBZ]05209.doc:BAV