United States Patent
`
`[19]
`
`[11] Patent Number:
`
`5,741,817
`
`Chowhan et a].
`
`[45] Date of Patent:
`
`Apr. 21, 1998
`
`USOOS741817A
`
`[54] USE 0]" LOW MOLECULAR WEIGHT
`AMINO ACIDS IN OPHTHALNIIC
`COMPOSITIONS
`
`[76]
`
`Inventors: Masood Chowhan. 2305 Busch Dr..
`Arlington. Tex, 76014; Bahrain
`Asgharian. 6628 Townlake Cir..
`Arlington. Tex. 76016' Paul Stach
`‘
`’
`.
`2736 W°°d5t°Ck Rd" Upper Admgton‘
`013110 43221
`
`[21] APPI' N05 5751740
`[22] Filed:
`Dec. 18 1995
`’
`Related US. Application Data
`_
`.
`[63] Conunuauon of Ser. No. 279,324, Jul. 22, 1994, abandoned.
`[51]
`Int. Cl.6 ................................................... A61K 31/195
`[52] US. Cl.
`............
`514/561; 514/912
`
`[5 8] Field of Search ...................................... 514/561. 912
`
`[56]
`
`References Cited
`
`U'S' PATENT DOCUMENTS
`
`252/107
`4,410,442 10/1983 Lucas et a1.
`.
`
`252/106
`4,504,405
`3/1985 Howes
`4,525,346
`6/1985 Stark ......................................... 424/80
`
`4,710,313 12/1987 Miyajima et a1.
`...................... 252/105
`
`5,011,661
`4/1991 Schiifer et a1.
`
`2/1995 Allen ..................................... 424/944
`5,389,369
`FOREIGN PATENT DOCUMENTS
`
`4/1984 Australia .
`560506
`1/1989 Australia ....................... A01N 63/02
`A-18604/88
`7/1983
`European Pat. 011.
`.
`0 297 598 A2
`11/1993 WIPO .
`W0 93f21903
`WO 95/30414 11/1995 WIPO ............................ A61K 31/20
`UTHER PUBLICATIONS
`
`Collin. et al.. ‘The Effects of NaQEDTA on Keratocytes and
`Endothelium of the Isolated Guinea Pig Cornea". Interna-
`rional Contact Lens Clinic. v01. 9. No. 5. pp. 281—287
`(SCP-IOCL 1932)-
`Primary Examiner—Zohreh Fay
`Attorney Agent, or [pl-Megs C. Brown
`[57]
`ABSTRACT
`
`The use of glycine and other low molecular weight amino
`acids in ophthalmic compositions (e.g.. preserved saline
`solutions) is described. These compounds have been found
`to enhance the efficacy of antimiaobial preservatives. The
`compounds also act as chelating agents. buffers and tonicin
`agents.
`
`7 Claims, N0 Drawings
`
`Argentum Pharm. LLC V. Alcon Research, Ltd.
`Case IPR2017-01053
`
`ALCON 203 8
`
`

`

`1
`USE OF LOW MOLECULAR WEIGHT
`AMINO ACIDS IN OPHTHALMIC
`COMPOSITIONS
`
`5,741,817
`
`2
`
`This is a continuation of application Ser. No. 08/279324.
`?led Jul. 22. 1994. abandoned.
`
`BACKGROUND OF THE INVENTION
`
`The present invention relates to the ?eld of ophthalmol
`ogy. More speci?cally. the invention relates to the use of
`glycine and other low molecular weight amino acids in
`products for treating contact lenses. as well as other oph
`thalmic products. The amino acids described herein may
`serve several useful purposes in such compositions. but have
`been found to be particularly useful in enhancing the activity
`of antimicrobial preservatives.
`Ethylenediaminetetraacetic acid and the monosodium.
`disodium and trisodium salts thereof (collectively referred to
`herein as “EDIE/V) have been widely used for many years in
`ophthalmic products. particularly products for treating con
`tact lenses. It has been utilized in such products for various
`purposes. but particularly for its supplemental antimicrobial
`activity and as a chelating agent. The inclusion of EDTA in
`contact lens care products and other ophthalmic composi
`tions enhances the antimicrobial e?icacy of chemical pre
`servatives contained in such compositions. particularly the
`ef?cacy of those preservatives against gram negative bacte
`ria. However. some scientific studies have indicated that
`EDI‘A may damage corneal cells. See. e.g.. Collin. et al..
`‘The Effects of Na2EDTA on Keratocytes and Endothelium
`of the Isolated Guinea Pig Cornea”. International Contact
`Lens Clinic, volume 9. number 5. September/October 1982.
`Further. it is incompatible with certain components of com
`positions for treating contact lenses. such as chlorine. iodine
`and other oxidizing agents.
`In view of the foregoing circumstances. there is a need for
`a new agent which can perform essentially the same func
`tions as EUI‘A. but which is more compatible with corneal
`cells and chemically compatible with oxidizing agents. The
`new use of glycine and other low molecular weight amino
`acids described herein is directed to satisfying this need.
`
`10
`
`20
`
`25
`
`30
`
`35
`
`SUMIVIARY OF THE INVENTION
`
`The present invention is based on a new use of glycine
`and other low molecular weight amino acids. The present
`inventors have found that such amino acids enhance the
`activity of antimicrobial preservatives. and are also useful as
`chelating agents. The low molecular weight amino acids can
`also serve as bu?ters and tonicity agents. Based on these
`properties. glycine and the other amino acids described
`herein can be utilized in various types of ophthalmic
`compositions. particularly compositions for treating contact
`lenses. such as disinfectants. cleaners. comfort drops and
`rewetting drops. instead of EDTA. The low molecular
`weight amino acids are particularly useful in preserved
`saline solutions which are utilized for rinsing and storing
`contact lenses.
`
`45
`
`50
`
`55
`
`DESCRIPTION OF PREFERRED
`EMBODIMENTS
`
`The low molecular weight amino acids which may be
`utilized in the present invention have a molecular weight in
`the range of from about 75 to about 250. The following
`compounds are representative of me low molecular weight
`amino acids which may be utilized in the present invention:
`
`65
`
`L-Alanine
`ot-Aminoadipic Acid
`y-Aminobutyric Acid
`Arginine
`Aspartic Acid
`Creatine
`Glycine
`Cystine
`Lysine
`Ornithine
`Phophoserine
`Threonine
`
`B-Alanine
`(x-Aminobutyric Acid
`ot-Aminoisobutyric Acid
`Asparagine
`Citrulline
`Glutamic Acid
`Histidine
`Leucine
`Norleucine
`Phenylalanine
`Sarcosine
`Valine
`
`Amino acids which include alpha (a) carboxylic acid groups
`are preferred.
`The amount of amino acid utilized will depend on the
`molecular weight of the amino acid(s) selected. In general.
`one or more of the above-described amino acids will be
`utilized in a concentration of from about 0.01 to about 7.5
`percent by weight/volume (“w/v%").
`The preferred amino acid for use in the present invention
`is glycine. Glycine is a relatively simple. low molecular
`weight amino acid It is also known as “aminoacetic acid".
`The amount of glycine utilized in the compositions of the
`present invention will vary depending on the type of com
`position in which it is contained. and the function of glycine
`in the composition. In general. compositions which contain
`glycine for purposes of enhancing the antimicrobial activity
`of the compositions will contain glycine in an amount of
`from about 0.01 to about 2.5 w/v%.. preferably from about
`0.1 to about 1.0 w/v%. Similar amounts of glycine will be
`utilized to perform the other functions mentioned above.
`The above-described low molecular weight amino acids
`may be combined with various ingredients conventionally
`utilized in ophthalmic products. particularly products for
`treating contact lenses. More specifically. these compounds
`may be utilized to enhance the antimicrobial activity of an
`ophthalmic composition. so as to preserve the composition
`against microbial contamination. Additionally. such com
`pounds contribute to the tonicity. chelating and buffering
`properties of the composition.
`The low molecular weight amino acids described herein
`may be included in various types of ophthalmic composi
`tions to enhance antimicrobial activity. or for the other
`purposes mentioned above. The types of compositions
`include: ophthalmic pharmaceutical compositions. such as
`topical compositions used in the treatment of glaucoma.
`infections. allergies or inflammation: compositions for treat
`ing contact lenses. such as cleaning products and products
`for enhancing the ocular comfort of patients wearing contact
`lenses: and various other types of compositions. such as
`ocular lubricating products. arti?cial tears. astringents. and
`so on. The compositions may be aqueous or nonaqueous. but
`will generally be aqueous.
`The compositions of the present invention may contain
`one or more antimicrobial agents to preserve the composi
`tions from microbial contamination. For example. the com
`positions may contain the antimicrobial agent known as
`POLYQUAD®; the use of this agent as a preservative in
`ophthalmic compositions is described in US. Pat. No.
`4.525346 (Stark). The entire contents of the Stark 346
`patent are hereby incorporated in the present speci?cation by
`reference. Additional examples of antimicrobial agents
`include chlorhexidine. alexidine. hexetidine. polyhexameth~
`ylene biquanide. benzalkonium chloride. benzododecinum
`bromide. and other antimicrobial agents utilized as antimi
`crobial perservatives in ophthalmic compositions. The inclu
`sion of one or more of the above-described low molecular
`
`

`

`5.741.817
`
`4
`“preservative effectiveness test”. The above-described com
`position is referred to below as “Formulation A”.
`EXAMPLE 2
`The antimicrobial efficacy of Formulation A was evalu
`ated. More speci?cally. the antimicrobial activity this saline
`solution was evaluated by inoculating 20 milliliters (“ml")
`of the solution with 0.1 ml of a microbial suspension. The
`?nal concentran'on was approximately 106 colony forming
`units per ml. At each time pull. the number of survivors was
`determined by taking a 1 ml aliquot of the test sample.
`serially diluting in 9 ml of saline at selected time intervals
`and preparing pour plates of SCDA. The bacteria and yeast
`plates were incubated at 30° C. to 35° C. for two to three
`days. The mold plates were incubated at 20° to 25° C. for
`?ve days. The results are presented in Table 1 below.
`
`20
`
`25
`
`35
`
`45
`
`TABLE 1
`
`Antimicrobial Activity of Formulation A
`
`Organism
`
`A. niger
`
`C. albicans
`
`R aeruginora
`
`E. cali
`
`S. aureus
`
`Time
`
`bog Reduction
`
`7 Days
`14 Days
`21 Days
`28 Days
`35 Days
`7 days
`14 Days
`21 Days
`28 Days
`7 Days
`14 Days
`21 Days
`28 Days
`7 Days
`14 Days
`21 Days
`28 Days
`7 Days
`14 Days
`21 Days
`28 Days
`
`2.5
`1.5
`1.5
`1.4
`1.6
`3.7
`4.7
`3.2
`4.5
`3.5
`5.2
`3.1
`3.8
`3.5
`4.9
`3.3
`3.9
`5.0
`5.0
`4.9
`4.6
`
`EXAMPLE 3
`
`Ingredient
`
`Boric Acid
`Sodium Borate
`Glycine
`Pationic 138C
`Puri?ed Water
`
`Concentration (w/v %)
`
`0.442
`0.0875
`1.61
`0.01
`q.s.
`
`10
`
`3
`weight amino acids in ophthalmic compositions containing
`such antimicrobial preservatives enhances the overall anti
`microbial activity of the compositions.
`As will be appreciated by those skilled in the art. the
`compositions may also contain a wide variety of other
`ingredients. such as tonicity agents (e.g.. sodium chloride or
`mannitol). surfactants (e.g.. alkyl ethoxylates and
`polyoxyethylene/polyoxypropylene copolymers). viscosity
`adjusting agents (e.g.. hydroxypropyl methyl cellulose and
`other cellulose derivatives) and buffering agents (e.g..
`borates. citrates. phosphates and carbonates). The use of a
`borate/mannitol buffering system is preferred The use of
`such systems is described in copending. commonly assigned
`U.S. patent application Ser. No. 081198.427 ?led Feb. 21.
`1994. and in corresponding PCT International Application
`Number PCl‘lUS93/04226 (International Publication Num
`ber WO 93/21903); the entire contents of the foregoing
`applications are hereby incorporated in the present specifu
`cation by reference. The present invention is not limited with
`respect to the types of ophthalmic compositions in which
`glycine and the other low molecular weight amino acids
`described above are utilized. However. the compositions of
`the present invention preferably do not contain EDTA.
`All of the above-described compositions will be formu
`lated so as to be compatible with the eye and/or contact
`lenses to be treated with the compositions. As will be
`appreciated by those skilled in the art. the ophthalmic
`compositions intended for direct application to the eye will
`be formulated so as to have a pH’ and tonicity which are
`compatible with the eye. This will normally require a bulfer
`to maintain the pH of the composition at or near physiologic
`pH (i.e.. 7.4) and may require a tonicity agent to bring the
`osmolality of the composition to a level at or near 280-320
`milliosmoles per kilogram (“mOsrn/kg”). The formulation
`of compositions for disinfecting and/or cleaning contact
`lenses will involve similar considerations. as well as con
`siderations relating to the physical e?ect of the compositions
`on contact lens materials and the potential for binding or
`absorption of the components of the composition by the lens.
`The following examples are presented to further illustrate
`the present invention.
`
`EXAMPLE 1
`
`Ingredient
`
`Boric Acid
`Mannitol
`Glycine
`Pationic 138C
`KOH/HCI
`Puri?ed Water
`
`Concentration (w/v %)
`
`1.0
`1.5
`0.75
`0.01
`pH 7.4
`q.s.
`
`The above composition represents an example of a saline
`solution which does not contain any conventional antimi
`crobial preservatives. This composition may be prepared by
`sequentially adding the ingredients to a portion of the
`distilled water and stirring the solution until each of the
`ingredients has dissolved. When all of the ingredients have
`been dissolved. the solution is brought to ?nal volume by the
`addition of the remainder of the water. and the pH is
`adjusted. if necessary. The solution has an osmolality of 295
`mOsrn/kg. It has been tested and found to meet the United
`States Pharmacopeia (“USP”) and United States Food and
`Drug Administration (“FDA") requirements for preservative
`effectiveness; those requirements are referred to below by
`means of the term “PET”. which is an abbreviation for
`
`55
`
`The above composition. which is referred to herein as
`“Formulation B". represents an example of a saline solution
`containing a relatively high concentration of glycine in a
`borate bu?er. This solution was prepared by means of a
`procedure similar to the procedure described in Example 1
`above. The pH of the solution was 7.6 and the osmolality
`was 295 mOsm/kg. The antimicrobial activity of Formula
`tion B was evaluated against a gram negative and a gram
`positive bacteria by means of the procedures described in
`Example 2. The solution showed a 2.2 log reduction against
`S. aureus and a 3.8 log reduction against P. aeruginosa at 7
`days.
`
`65
`
`EXAMPLE 4
`The following compositions were tested to determine if
`EDTA could simply be eliminated from saline solutions; the
`
`

`

`5
`compositions were prepared by means of procedures similar
`to the procedure described in Example 1 above:
`
`5,741,817
`
`6
`EXAMPLE 6
`
`Concentration (w/v %)
`
`Ingredient
`
`Formulation C Formulation D Formulation E
`
`Boric Acid
`Sodium Borate
`Sodium Chloride
`Pationic 138C
`Disodiurn Edetate
`Puri?ed Water
`
`0.442
`0.0875
`0.675
`—-
`—
`q.s
`
`0.442
`0.0875
`0.675
`0.01
`—
`q.s.
`
`0.442
`0.0874
`0.675
`0.01
`0.1
`q.s.
`
`Formulation C has a pH of 7.7 and osmolality of 299
`mOsm/kg. Formulation D has a pH of 7 .7 and osmolality of
`294 mOsm/kg. and Formulation E has a pH of 7.3 and
`osmolality of 305 mOsm/lcg. The compositions were tested
`for antimicrobial activity by means of the procedures
`described in Example 2. The results. expressed as the
`number of log reductions after 7 days. are listed below:
`
`Antimicrobial Activity (i.e.. Log Reduction at Day 7]
`Against PET Microorganisms
`
`Fonnulation C
`
`Formulation D Formulation E
`
`A. niger
`I’. aeruginosa
`S. aureus
`
`1.8
`0.0
`1.6
`
`1.9
`0.4
`4.1
`
`1.0
`4.1
`5.0
`
`Ingredient
`
`Concentration (w/v %)
`
`Polyvinyl alcohol
`Hydroxyethyl cellulose
`Boric acid
`Sodium horate
`Mamiitol
`Glycine
`Polyquad 1'"
`Puri?ed water
`
`0.75
`0.28
`0.35
`0.11
`2.0
`0.5
`0.001
`q.s.
`
`20
`
`25
`
`The above composition is an example of a composition
`for lubricating contact lenses or increasing the comfort of
`contact lenses when worn by patients. The composition is
`prepared in two parts and then recombined. In order to
`prepare the ?rst part. polyvinyl alcohol and hydroxyethyl
`cellulose are dispersed in 40 ml of puri?ed water at a
`temperature of 50°—70° C.. and then allowed to hydrate and
`cool to room temperature. The solution is then Polish ?ltered
`using a 5-20 micrometer (‘pm") membrane ?lter and auto
`claved. In order to prepare the second part. the remaining
`ingredients are dissolved in 50 ml of puri?ed water. This
`solution is then sterile ?ltered using a 0.22 um membrane
`?lter into a sterile receiving container. The ?rst part and the
`second part are then combined aseptically and the pH of the
`resulting solution is adjusted to 7.4. The volume of the
`solution is then brought to 100 ml with puri?ed water. The
`solution has an osmolality of 230-260 mOsm/kg.
`The use of a low molecular weight amino acid in this
`composition enhances the antimicrobial activity of the
`composition. and also eliminates the need for an additional
`tonicity agent. such as sodium chloride.
`
`Both Formulation C and Formulation D failed USP and
`FDA requirements for preservative effectiveness. while For
`mulation E met those requirements. These results clearly
`demonstrate that EDI‘A cannot simply eliminated. This is
`particularly true relative to Pseudomonas aeruginosa.
`However. the results presented in Examples 2 and 3 dem
`onstrate that EDTA can be replaced by low molecular weight
`amino acids. such as glycine.
`
`35
`
`EXAMPLE 5
`
`Concentration (w/v %)
`
`0.35
`0.11
`1.5
`0.75
`0.001
`q.s.
`
`Ingredient
`
`Boric acid
`Sodium borate
`Mannitol
`Glycine
`Polyquad
`Puri?ed water
`
`The above composition represents an example of the
`preserved saline solutions of the present invention. wherein
`a low molecular weight amino acid is utilized to augment the
`activity of a conventional antimicrobial preservative. This
`composition may be prepared by sequentially adding the
`listed ingredients to 90 ml of puri?ed water and stirring until
`each ingredient has dissolved. The pH is adjusted to 7.4 and
`the volume is adjusted to 100 ml. The low molecular weight
`amino (i.e.. glycine) contributes to the antimicrobial prop
`erties of the solution. as well as to the tonicity and chelating
`properties of the solution.
`
`45
`
`50
`
`55
`
`65
`
`EXAMPLE 7
`
`Ingredient
`
`Concentration (w/v %)
`
`Polaxamine
`Boric acid
`Mannitol
`Sodium chloride
`Glycine
`Polyhexamethylene
`big
`. ]
`Puri?ed water
`
`0.25
`0.5
`1.5
`0.15
`0.25
`0.0005
`
`q.s.
`
`The above composition is an example of a multi-purpose
`solution for cleaning. disinfecting and storing contact lenses.
`The composition was prepared by sequentially adding the
`ingredients to 90 ml of puri?ed water and stirring until each
`ingredient was dissolved. The pH of the resulting solution
`was adjusted to 7.4. and the volume was adjusted to 100 ml
`with puri?ed water. The low molecular weight amino acid
`performs the same function in this composition as in the
`other compositions described above.
`What is claimed is:
`1. A method of enhancing the antimicrobial activity of an
`ophthalmic composition which comprises adding to the
`composition an effective amount of a low molecular weight
`amino acid. said amino acid including an alpha carboxylic
`acid group and having a molecular weight of 75 to 250.
`wherein the ophthalmic composition does not contain
`EDTA.
`2. A method according to claim 1. wherein the amino acid
`comprises glycine.
`3. A method according to claim 1. wherein the composi
`tion is a contact lens disinfecting solution.
`
`

`

`5,741,817
`
`7
`4. A method according to claim 2. wherein the composi
`tion is a contact lens disinfecting solution.
`5. A method according to claim 1. wherein the composi
`tion is a saline solution adapted for rinsing and storing
`contact lenses.
`6. A method according to claim 5. wherein the low
`molecular weight amino acid comprises glycine in an
`amount effect to preserve the saline solution from microbial
`contamination.
`7. A method according to claim 6. wherein the saline 10
`solution has the following formula:
`
`5
`
`Ingredient
`
`Boric Acid
`Marmitol
`Glycine
`Pationic 133C
`KOH/HCI
`Puri?ed Water
`
`Concentration (w/v %)
`
`140
`15
`0,75
`0B1
`pH 7.4
`q.s..
`
`