Humectant eye drops comprising a synergistic combination of nicotinamide and adenosine

Abstract

A novel humectant eye drop composition is disclosed. The composition comprises a synergistic combination of nicotinamide and adenosine in concentrations at which neither component is effective individually. In preferred embodiments of the invention, the composition comprises 0.025% (w / v) and 0.05% (w / v) nicotinamide. Within 2 - 3 weeks of commencement of application, the composition improves the Tear Film Breakup Time, improves tear production as measured by the Schirmer Test, reduces the severity of the Dry Eye Syndrome as measured by Lissamine Green staining, and shows anti-inflammatory effects.

Description

HUMECTANT EYE DROPS COMPRISING A SYNERGISTIC COMBINATION OF NICOTINAMIDE AND ADENOSINECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional Application No. 63 / 723,231, filed 21 November 2024.FIELD OF THE INVENTION

[0002] The invention disclosed herein is generally directed to humectant eye drops. It relates more specifically to eye drops that comprise nicotinamide and adenosine as active ingredients.BACKGROUND OF THE INVENTION

[0003] Dry Eye Syndrome (DES), also known as keratoconjunctivitis sicca, is a condition that occurs when the eye is insufficiently lubricated by the tears. This condition, which is estimated to affect 16 million Americans, can arise from a number of causes, such as insufficient tear production, production of low-quality tears, or too-rapid tear evaporation [1], is characterized by a lowering of the Tear-Film Breakup Time (TBUT), the time at which the first dry spot appears on the cornea following a blink, from its normal value of 10 - 35 s. The first-line treatment for DES is generally topical application of humectant eye drops or gels. These topical treatments generally provide temporary relief of symptoms, but their effectiveness is frequently limited by the extent to which they can restore the TBUT.

[0004] Compounds that have been of recent interest in treatments for restoration of ocular health have included adenosine and nicotinamide and derivatives thereof.

[0005] Adenosine receptors have been proposed as targets for management of ocular disease [2], While it has been reported that topical application of a composition comprising 2% 6-aminonicotinamide and 0.1% adenosine was an effective treatment, both in vivo and ex vivo, for acute corneal inflammation, the maj ority of the literature that reports on the use of adenosine as a topical ocular treatment considers its use as a treatment for glaucoma [3], As an example, topical application of an 0.1% adenosine solution was reported to have lowered intraocular pressure (IOP) in an animal model of glaucoma [4],

[0006] Nicotinamide derivatives, particularly nicotinamide mononucleotide (NMN), have also been used to treat ocular conditions. For example, U.S. Pat. Appl. Pub. No. 2016 / 0022712 discloses a treatment to improve tear production in an animal model that comprised daily oral administration of 300 mg / kg NMN to adult mice over a 12-month period, and topicalapplication of NMN to the eyes as a treament for macular degeneration. It has been reported that application of 500 11M NMN in vitro to corneal epithelial cells that had undergone hyperosmotic stress to down-regulate Interleukin- 17a expression [5], NMN has also been suggested as a possible treatment for ocular diseases including ocular inflammation, oxidative stress, and complex metabolic dysregulation in murine models for eye diseases such as ischemic retinopathy, corneal defect, glaucoma, and age-related macular degeneration [6],

[0007] PCT Pat. Appl. Pub. No. WO2023 / 152642 discloses an ophthalmic composition comprising atropine or a pharmaceutically acceptable salt thereof and nicotinamide. Treatment with nicotinamide is reported as possibly acting to reduce intraocular pressure in patients with glaucoma.

[0008] Application of nicotinamide has also been reported to speed the repair of injury to human corneal endothelial cells [7], The authors of the study reported a statistically significant improvement in repair to damage to corneal endothelial cells was reported upon exposure of in vitro cultured human corneal endothelial cells to a 5 mM (0.06% w / v) nicotinamide solution. Similarly, topical application of a 2.5 M (30% w / v) nicotinamide solution to damaged corneal cells in vivo in an animal model was reported by the authors of the study to have provided a statistically significant improvement in healing of damaged corneal epithelial cells.

[0009] It is clear from the foregoing that despite the considerable amount of effort devoted to the problem, an improved formulation for topical application to the eyes that relieves symptoms of DES and extends the TBUT, remains a long -felt, but as yet unmet need.SUMMARY OF THE INVENTION

[0010] The invention disclosed herein is designed to meet this need. An eye drop composition for topical application to an affected eye is disclosed, in which the composition contains a synergistic combination of nicotinamide and adenosine in aqueous solution in which the two components are present at concentrations at which neither is effective individually.

[0011] It is therefore an object of this invention to disclose a humectant eye drop composition, wherein said eye drop composition comprises an aqueous solution comprising adenosine and nicotinamide.

[0012] It is a further object of this invention to disclose the humectant eye drop composition as defined in the preceding, wherein said eye drop composition comprises adenosine and nicotinamide in concentrations that together demonstrate synergistic reduction of expression of at least one substance selected from the group consisting of interleukin- la, interleukin- ip,interleukin-6, and tumor necrosis factor a. In preferred embodiments of the invention, at least one of said adenosine and said nicotinamide is present in a concentration which, when applied alone, is insufficient to produce statistically significant (p < 0.05) reduction of expression of at least one substance selected from the group consisting of interleukin- la, interleukin- ip, interleukin-6, and tumor necrosis factor a.

[0013] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said composition is isotonic.

[0014] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said composition is characterized by nonNewtonian rheological properties.

[0015] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said aqueous solution comprises adenosine, nicotinamide, a polymer characterized by an average molecular weight of >10,000 Da, and acid or base as necessary to adjust a pH of said aqueous solution to a value of 6.5 - 7.5. In some preferred embodiments of the invention, said polymer is selected from the group consisting of hyaluronate and carbomer. In some especially preferred embodiments of the invention, said composition comprises 0.2 - 0.6% (w / v) Carbomer 981.

[0016] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said aqueous solution comprises adenosine and nicotinamide in a ratio of 1 :5 - 5: 1 (w / v).

[0017] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said eye drop composition is characterized by an adenosine concentration of 0.01% - 0.5% (w / v) and a nicotinamide concentration of 0.01% - 0.5% (w / v). In some preferred embodiments of the invention, said eye drop composition is characterized by an adenosine concentration of 0.01% - 0.05% (w / v) and a nicotinamide concentration of 0.01% - 0.05% (w / v). In some especially preferred embodiments of the invention, said eye drop composition further comprises 0.2 - 0.6% (w / v) Carbomer 981.

[0018] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said eye drop composition comprises an aqueous solution comprising 0.025% (w / v) adenosine, 0.05% (w / v) nicotinamide, and sufficient acid or base to adjust the pH to a value of 6.5 - 7.5. In some preferred embodiments of the invention, said eye drop composition further comprises 0.20% (w / v) Carbomer 981. In some preferredembodiments of the invention, said eye drop composition further comprises 0.15% (w / v) sodium hyaluronate. In some especially preferred embodiments of the invention in which the composition comprises sodium hyaluronate, said hyaluronate is characterized by a molecular weight of 1500 - 1800 kDa.

[0019] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said eye drop composition further comprises at least one excipient selected from the group consisting of stabilizers, buffers, antioxidants, and combinations and mixtures thereof.

[0020] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said eye drop composition further comprises a preservative.

[0021] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said eye drop composition is preservative-free.

[0022] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said eye drop composition further comprises a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof. In some preferred embodiments of the invention, wherein said composition is characterized by a trehalose concentration equivalent to 3 - 6% (w / v) anhydrous trehalose.

[0023] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said composition comprises an aqueous solution comprising 0.01% - 0.05% (w / v) adenosine; 0.01% - 0.05% (w / v) nicotinamide; 0.2 - 0.6% (w / v) Carbomer 981; a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof in a concentration equivalent to 3% anhydrous trehalose; and sufficient acid or base to adjust the pH to a value of 6.5 - 7.5.

[0024] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said composition comprises an aqueous solution comprising 0.01% - 0.05% (w / v) adenosine; 0.01% - 0.05% (w / v) nicotinamide; a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof in a concentration equivalent to 3%; 0.6% (w / v) Carbomer 981; 0.64% NaCl; a component selected from the group consisting of anhydrous trehalose, trehalosedihydrate, and mixtures and combinations thereof in a concentration equivalent to 3% anhydrous trehalose; and sufficient acid or base to adjust the pH to a value of 6.5 - 7.5.

[0025] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said eye drop composition further comprises a pharmaceutically effective concentration at least one pharmacologically active agent. In some preferred embodiments of the invention, said eye drop composition further comprises at least one substance appropriate for use with said pharmacologically active agent, said at least one substance selected from the group consisting of stabilizers, antioxidants, buffers, and combinations and mixtures thereof. In some embodiments of the invention in which it comprises at least one pharmacologically active agent, said eye drop composition further comprises a preservative. In some other embodiments of the invention in which it comprises at least one pharmacologically active agent, said eye drop composition is preservative-free.

[0026] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding, wherein said eye drop composition consists of an aqueous solution consisting of adenosine, nicotinamide, sufficient acid or base to adjust the pH to a value of 6.5 - 7.5, and at least one component selected from the group consisting of Carbomer 981, sodium hyaluronate, hyaluronic acid, and trehalose. In some preferred embodiments of the invention, said eye drop composition consists of an aqueous solution consisting of 0.025% (w / v) adenosine, 0.05% (w / v) nicotinamide, sufficient acid or base to adjust the pH to a value of 6.5 - 7.5, and a component selected from the group consisting of 0.20% (w / v) Carbomer 981 and 0.15% (w / v) sodium hyaluronate. In some other preferred embodiments of the invention, said eye drop composition consists of an aqueous solution consisting of 0.025% (w / v) adenosine; 0.05% (w / v) nicotinamide; a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof in a concentration equivalent to 3% anhydrous trehalose; sufficient acid or base to adjust the pH to a value of 6.5 - 7.5; and a component selected from the group consisting of 0.20% (w / v) Carbomer 981 and 0.15% (w / v) sodium hyaluronate. In yet other preferred embodiments of the invention, said eye drop composition consists of an aqueous solution consisting of 0.025% (w / v) adenosine; 0.05% (w / v) nicotinamide; a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof in a concentration equivalent to 3% anhydrous trehalose; sufficient acid or base to adjust the pH to a value of 6.5 - 7.5; 0.64% NaCl; and 0.6% (w / v) Carbomer 981.

[0027] It is a further object of this invention to disclose a method of treatment of Dry Eye Syndrome, wherein said method comprises applying topically to an eye of a patient in need the humectant eye drop composition as defined in any of the preceding.

[0028] It is a further object of this invention to disclose the method as defined in the preceding, wherein said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Schirmer's Test Score is observed.

[0029] It is a further object of this invention to disclose the method as defined in any of the preceding, wherein said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Tear Film Breakup Time (TBUT) is observed.

[0030] It is a further object of this invention to disclose the method as defined in any of the preceding, wherein said method comprises applying said humectant eye drop composition 1 - 4 times daily.

[0031] It is a further object of this invention to disclose the method as defined in any of the preceding, wherein said method comprises applying said humectant eye drop composition 1 - 4 times daily for a period of three weeks.

[0032] It is a further object of this invention to disclose a method of relief of symptoms of Dry Eye Syndrome, comprising applying topically to an eye of a patient in need the humectant eye drop composition as defined in any of the preceding until at least partial relief of said symptoms is observed.

[0033] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding for use in a method of treatment of Dry Eye Syndrome, wherein said method comprises applying said humectant eye drop composition topically to at least one eye of a patient in need. In some preferred embodiments of the invention, said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Schirmer's Test Score is observed. In some preferred embodiments of the invention, said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Tear Film Breakup Time (TBUT) is observed. In some preferred embodiments of the invention, said method comprises applying said eye drop composition 1 - 4 times daily for a period of three weeks.

[0034] It is a further object of this invention to disclose the humectant eye drop composition as defined in any of the preceding for use in a method of treatment of symptoms of Dry EyeSyndrome, wherein said method comprises applying said eye drop composition topically to at least one eye of a patient in need until at least partial relief of said symptoms is obtained.

[0035] It is a further object of this invention to disclose the use of the humectant eye drop composition as defined in any of the preceding in a method of treatment of Dry Eye Syndrome, wherein said method comprises applying topically to at least one eye of a patient in need said eye drop composition. In some preferred embodiments of the invention, wherein said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Schirmer's Test Score is observed. In some preferred embodiments of the invention, said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Tear Film Breakup Time (TBUT) is observed. In some preferred embodiments of the invention, said method comprises applying said humectant eye drop composition 1 - 4 times daily. In some preferred embodiments of the invention, said method comprises applying said humectant eye drop composition 1 - 4 times daily for a period of three weeks. In some preferred embodiments of the invention, said method comprises applying said eye drop composition topically to at least one eye of a patient in need until at least partial relief of said symptoms is obtained. In some preferred embodiments of the invention, said method comprises applying said humectant eye drop composition 1 - 4 times daily. In some preferred embodiments of the invention, said method comprises applying said humectant eye drop composition 1 - 4 times daily for a period of three weeks.BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention will now be described with reference to the drawings, wherein:

[0037] FIGs. 1A - ID present graphs showing expression of Interleukin- la in human corneal epithelial cells cultured in vitro and exposed to solutions of nicotinamide, adenosine, and a combination of the two, according to two corneal cell inflammation models;

[0038] FIGs. 2A - 2D present graphs showing expression of Interleukin- ip in human corneal epithelial cells cultured in vitro and exposed to solutions of nicotinamide, adenosine, and a combination of the two, according to two corneal cell inflammation models;

[0039] FIGs. 3A - 3D present graphs showing expression of Interleukin-6 in human corneal epithelial cells cultured in vitro and exposed to solutions of nicotinamide, adenosine, and a combination of the two, according to two corneal cell inflammation models;

[0040] FIGs. 4A - 4D present graphs showing expression of Tumor Necrosis Factor a in human corneal epithelial cells cultured in vitro and exposed to solutions of nicotinamide, adenosine, and a combination of the two, according to two corneal cell inflammation models;

[0041] FIGs. 5A and 5B present results of Schirmer Test measurements of tear secretion performed during an animal model study of the efficacy of the eye drops of the instant invention;

[0042] FIGs. 6A and 6B present results of measurements of Tear Film Breakup Time (TBUT) performed during the aforementioned animal model study of the efficacy of the eye drops of the instant invention; and,

[0043] FIGs. 7A and 7B present results of Lissamine Green staining tests performed during the aforementioned animal model study of the efficacy of the eye drops of the instant invention.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] In the following description, various aspects of the invention will be described. For the purposes of explanation, specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent to one skilled in the art that there are other embodiments of the invention that differ in details without affecting the essential nature thereof. Therefore, the invention is not limited by that which is illustrated in the figures and described in the specification, but only as indicated in the accompanying claims, with the proper scope determined only by the broadest reasonable interpretation of said claims. In some cases, for clarity or conciseness, individual elements of the invention are discussed separately. Nonetheless, any combination of individual elements of the invention disclosed herein that is not self-contradictory is considered by the inventors to be within the scope of the invention.

[0045] In all cases in which an embodiment is described as "comprising" a set of components or method steps, i.e. the invention may include components or method steps in addition to those explicitly listed, the scope of invention is to be understood to include embodiments in which the invention "consists of' the listed components or method steps, i.e. embodiments that include the listed components or method steps and no others, and to include as well embodiments in which the invention "consists essentially of' the listed components or method steps, i.e. embodiments that do not include any components or method steps not listed that would materially affect the basic and novel characteristics of the invention.

[0046] Unless specifically stated otherwise, any range disclosed herein is understood to include within its scope the stated endpoints of the range and any subrange. As non-limiting examples,if a range is stated to be "1 - 10%, " 1% and 10% are considered to be included in the range, and ranges of 1 - 5%, 2 - 9%, etc., are considered by the inventors to be within the scope of the invention; similarly, if a range is stated to be "less than 50%, " ranges of less than 40%, less than 25%, less than 10%, etc., are considered to be within the scope of the invention.

[0047] As used herein, unless defined otherwise, with reference to numerical quantities, the term "about" refers to a range of ±25% about the nominal value.

[0048] As used herein, unless defined otherwise, the term "statistically significant" is used to denote a result that has a statistical significance of p < 0.05.

[0049] Unless defined otherwise, all concentrations disclosed herein are expressed as percentage weight / volume (%w / v, typically expressed as g solute / 100 ml solution).

[0050] As used herein, the abbreviation "DES" is used to stand for the expression "Dry Eye Syndrome."

[0051] As used herein, the abbreviation "TBUT" is used to stand for the expression "Tear-Film Breakup Time."

[0052] As used herein, the abbreviation "HCEC" is used to stand for the expression "Human Corneal Epithelial Cell."

[0053] As used herein, unless specifically defined otherwise, unless the degree of hydration or the state of hydration is specified, the generic term "trehalose" is used to describe trehalose without reference to its degree of hydration. Similarly, as used herein, an amount of trehalose described as "equivalent" to a given weight of anhydrous trehalose indicates that the weight was calculated excluding water of hydration. As a non-limiting example, as the term is used herein, approximately 1.11 g of trehalose dihydrate is "equivalent" to 1.0 g of anhydrous trehalose.

[0054] Disclosed herein is a novel humectant eye drop composition. The eye drop composition is shown to be an effective topical treatment of DES and symptoms thereof. The composition comprises an aqueous solution comprising a synergistic combination of nicotinamide and adenosine. The inventors have found that, surprisingly, the composition disclosed herein is an effective topical treatment for DES even though the concentrations of the components of the composition are much lower (by about one order of magnitude) than concentrations of nicotinamide and adenosine used in prior art compositions for treatment of DES. As shown in detail below, in preferred embodiments, the nicotinamide and adenosine are present inconcentrations at which at least one of them is not an effective treatment for DES or symptoms thereof when applied topically in the absence of the other. In especially preferred embodiments of the invention, neither nicotinamide nor adenosine is present in a concentration in which the component on its own is an effective treatment for DES or symptoms thereof when applied topically.

[0055] It is well-known in the art that eye drops having non-Newtonian rheological properties more accurately mimic the behavior of human tears than eye drops having Newtonian rheological properties; see, for example, U.S. Pat. No. 5106615 (henceforth '615). Therefore, in preferred embodiments of the current invention, the eye drop composition comprises at least one physiologically compatible polymer in a concentration sufficient to give it non-Newtonian rheological properties. In typical embodiments of the invention, the high-molecular weight polymer is present in a concentration of 0.15% - 0.60% (w / v). In preferred embodiments of the invention, the polymer is characterized by a molecular weight > 10,000 Dalton. Nonlimiting examples of suitable polymers include crosslinked acrylates such as Carbomer 981 (commercially available from several suppliers under various trade names such as CARBOPOL 981) and hyaluronate. In those embodiments that include hyaluronate, it is typically provided as sodium hyaluronate or hyaluronic acid.

[0056] It is disclosed in '615 that high concentrations of inorganic salts can disrupt the nonNewtonian rheological properties of an eye drop composition. Therefore, in especially preferred embodiments of the instant invention, the eye drop composition comprises <0.7% (w / v) inorganic salts. The inventors of the instant invention have found that in embodiments of the invention in which an inorganic salt is added (as a non-limiting example, salt made be added in order to maintain the osmolarity of the composition at a predetermined value), in order to maintain the non-Newtonian rheological properties of the composition, more high-molecular weight polymer must be added relative to embodiments in which the osmolarity of the composition is acceptable without addition of inorganic salts. Non-limiting embodiments of the invention that illustrate qualitatively this relation between the concentrations of salt and polymer are given in Examples 3 - 6 below.

[0057] In preferred embodiments of the invention, the eye drop composition is characterized by a physiologically acceptable pH, most preferably 6.5 - 7.5. Thus, in preferred embodiments of the invention, the composition comprises sufficient acid or base to bring the pH to a value of 6.5 - 7.5.

[0058] In preferred embodiments of the invention, the eye drops are isotonic.

[0059] The water used to prepare the eye drops is of purity sufficient for topical application to the eyes. In typical embodiments, the water used for preparation of the eye drops is sterile, preferably chlorine-free, and has undergone a purification process such as distillation prior to its use in the preparation of the eye drops. In preferred embodiments of the invention, the eye drops are prepared and packaged under aseptic conditions in order to maintain their sterility.

[0060] In preferred embodiments of the invention, the adenosine and nicotinamide are present in a w / v ratio of 1 :5 - 5: 1. In some particularly preferred embodiments of the invention, the eye drop composition comprises 0.001% - 0.05% (w / v) adenosine and 0.001% - 0.1% (w / v) nicotinamide. In more preferred embodiments of the invention, the eye drop composition comprises 0.025% (w / v) adenosine, 0.05% (w / v) nicotinamide, and sufficient acid or base to adjust the pH to a value of 6.5 - 7.5, along with a high-molecular weight polymer. Non-limiting examples of preferred polymers include 0.20% (w / v) Carbomer 981 or 0.15% (w / v) sodium hyaluronate. The sodium hyaluronate is preferably characterized by a molecular weight in the range of 1500 - 1800 kDa.

[0061] The composition may optionally include other excipients such as stabilizers, buffers, preservatives, antioxidants, or any combination thereof. One non-limiting example of an excipient that is suitable for use in the humectant eye drops disclosed herein is trehalose, which is well-known in the art as a stabilizer suitable for use in eye drops. The inventors have found that the anhydrous and dihydrate forms of trehalose may be used interchangeably in the instant invention. In some preferred embodiments of the invention, the composition comprises anhydrous trehalose, trehalose dihydrate, or a mixture or combination thereof in a concentration equivalent to 3 - 6% (w / v) anhydrous trehalose. In particularly preferred embodiments, the composition comprises anhydrous trehalose, trehalose dihydrate, or a mixture or combination thereof in a concentration equivalent to 3.0% (w / v) anhydrous trehalose.

[0062] In some embodiments, the solution additionally comprises a pharmaceutically effective concentration at least one pharmacologically active agent. If necessary, any stabilizer, preservative, antioxidant, buffer or combination thereof appropriate for use with the pharmacologically active agent may be added to the solution in any concentration suitable for use in eye drops.

[0063] In preferred embodiments of the invention, in particular, those in which the composition does not comprise hyaluronate, the eye drop composition is preservative-free; that is, no preservative is added at any point in the preparation of the composition or to the container in which the eye drops are to be stored.

[0064] The eye drops are designed for use in a treatment in which they are topically applied to an eye of a patient suffering from Dry Eye Syndrome or symptoms thereof until the condition improves. Typical measurements of improvement include a statistically significant improvement in the TBUT as measured by any method known in the art, a significant improvement in tear production as measured by any method known in the art, or both. Nonlimiting examples of methods for measuring the TBUT include Lissamine Green and Rose Bengal staining, and non-limiting examples of methods for measuring tear production include Schirmer's Test.

[0065] The eye drops are typically taken 1 - 4 times daily, and improvement in the condition is typically observed within three weeks of the start of treatment.

[0066] As was explained in detail above, the instant eye drop composition comprises a synergistic combination of adenosine and nicotinamide, both of which are in concentrations that are an order of magnitude lower than the concentration at which either component is effective alone as a treatment for DES or symptoms thereof. One significant advantage of the instant eye drop composition is that, as it comprises low concentrations of relatively inexpensive active ingredients, it is less expensive to produce than other humectant eye drop compositions known in the art. In addition, in preferred embodiments, the instant invention has a relatively long shelf life and can be prepared without any necessity for addition of preservatives. Other advantages of the instant invention will be clear to a person of ordinary skill in the art.EXAMPLES

[0067] The following examples are presented in order to assist a person of ordinary skill in the art to make and use the invention disclosed herein, and are not intended to be limiting in any way.Example 1Eye drop composition - first embodiment

[0068] An eye drop composition was prepared according to the following formulation:

[0069] 0.025 g adenosine

[0070] 0.05 g nicotinamide

[0071] 0.20 g Carbomer 981

[0072] water to 100 ml

[0073] The pH was adjusted to a value of between 6.5 and 7.5, and the composition was then transferred to a sterile bottle for storage.Example 2Eye drop composition - second embodiment

[0074] An eye drop composition was prepared according to the following formulation:

[0075] 0.025 g adenosine

[0076] 0.05 g nicotinamide

[0077] 0 , 15 g sodium hyaluronate

[0078] water to 100 ml

[0079] The pH was adjusted to a value of between 6.5 and 7.5, and the composition was then transferred to a sterile bottle for storage.Example 3Eye drop composition - third embodiment

[0080] An eye drop composition was prepared according to the following formulation:

[0081] 0.025 g adenosine

[0082] 0.05 g nicotinamide

[0083] 3.0 g anhydrous trehalose

[0084] 0.20 g Carbomer 981

[0085] water to 100 ml

[0086] The pH was adjusted to a value of between 6.5 and 7.5, and the composition was then transferred to a sterile bottle for storage.Example 4Eye drop composition - fourth embodiment

[0087] An eye drop composition was prepared according to the following formulation:

[0088] 0.025 g adenosine

[0089] 0.05 g nicotinamide

[0090] 3 ,314 g trehalose dihydrate

[0091] 0.20 g Carbomer 981

[0092] water to 100 ml

[0093] The pH was adjusted to a value of between 6.5 and 7.5, and the composition was then transferred to a sterile bottle for storage.Example 5Eye drop composition - fifth embodiment

[0094] An eye drop composition was prepared according to the following formulation:

[0095] 0.025 g adenosine

[0096] 0.05 g nicotinamide

[0097] 3.0 g anhydrous trehalose

[0098] 0.60 g Carbomer 981

[0099] 0.64 g NaCl

[0100] water to 100 ml

[0101] The pH was adjusted to a value of between 6.5 and 7.5, and the composition was then transferred to a sterile bottle for storage.Example 6Eye drop composition - sixth embodiment

[0102] An eye drop composition was prepared according to the following formulation:

[0103] 0.025 g adenosine

[0104] 0.05 g nicotinamide

[0105] 3 ,314 g trehalose dihydrate

[0106] 0.60 g Carbomer 981

[0107] 0.64 g NaCl

[0108] water to 100 ml

[0109] The pH was adjusted to a value of between 6.5 and 7.5, and the composition was then transferred to a sterile bottle for storage.Example 7In vitro studies of adenosine - nicotinamide compositions

[0110] A series of experiments was performed to demonstrate the effectiveness of adenosine - nicotinamide compositions of the instant invention and the synergistic effect of compositions containing both components. Human corneal epithelial cells (HCECs) were cultured in vitro. The cells were then challenged by exposure either to 20 ug / ml of polyinosinic:polycytidylic acid (henceforth "Poly-IC model") or to an 0.001% solution of benzalkonium chloride (henceforth "BAK model") and cotreated with one of six treatment compositions: a solution of nicotinamide (0.0005% or 0.001% w / v), a solution of adenosine (0.0001% or 0.0005% w / v), or a solution comprising both (either 0.0005% nicotinamide + 0.0001% adenosine or 0.001% nicotinamide + 0.0005% adenosine). In order to determine a baseline for gene expression, cells were cultured without challenge, and as a control for the efficacy of the treatment compositions, cells were challenged as described above but not exposed to any treatment composition. In the figures, the relative gene expression is shown for the baseline, control, and experimental cells. Results for the baseline cells are shown as white bars, results for the challenged control cells as hatched bars, results for challenged cells exposed to nicotinamide alone as light gray bars, results for challenged cells exposed to adenosine alone as dark gray bars, and results for cells exposed to a composition containing both nicotinamide and adenosine as black bars. Error bars show Is uncertainties, and the percent inhibition of expression relative to the challenged control is given on the bar, where 0% = expression identical to that of the untreated challenged cells and 100% = expression equal to that of the baseline control cells.[OHl] Reference is now made to FIGs. 1A - ID, which show results of measurements of expression of interleukin- la, as determined by a Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) method for both the Poly-IC model (FIGs. 1A and IB) and for the BAK model (FIGs. 1C and ID) on in vitro cultured HCECs. FIGs. 1A and 1C show results for exposure to solutions containing 0.0005% (w / v) nicotinamide, 0.001% (w / v) adenosine, or 0.0005% (w / v) nicotinamide + 0.0001% (w / v) adenosine, and FIGs. IB and ID show results for exposure to solutions containing 0.001% (w / v) nicotinamide, 0.0005% (w / v) adenosine, or 0.001% (w / v) nicotinamide + 0.0005% (w / v) adenosine. As can be seen in the figures, in both models, nicotinamide alone produced at best a mild reduction in interleukin- la expression (upregulated by Poly-IC or BAK), while exposure to adenosine alone only began to produce significant reduction in the upregulated interleukin- la expression at the highest concentration used (0.0005%). Surprisingly, exposure of the cultured cells to a solutioncomprising either 0.0005% nicotinamide + 0.0001% adenosine or 0.001% nicotinamide + 0.0005% adenosine yielded significant reduction in upregulated interleukin- la expression, and the reduction was significantly greater than would have been expected from an additive combination of the observed effects of each component. In the case of exposure to a solution comprising 0.001% nicotinamide + 0.0005% adenosine, the upregulated expression of interleukin- la was reduced nearly to that of the untreated control cells.

[0112] Reference is now made to FIGs. 2A - 2D, which show results of measurements of expression of interleukin- ip, as determined by qRT-PCR, for the Poly-IC model (FIGs. 2A and 2B) and for the BAK model (FIGs. 2C and 2D) on in vitro cultured HCECs. FIGs. 2A and 2C show results for exposure to solutions containing 0.0005% (w / v) nicotinamide, 0.001% (w / v) adenosine, or 0.0005% (w / v) nicotinamide + 0.0001% (w / v) adenosine, and FIGs. 2B and 2D show results for exposure to solutions containing 0.001% (w / v) nicotinamide, 0.0005% (w / v) adenosine, or 0.001% (w / v) nicotinamide + 0.0005% (w / v) adenosine. Analogous results to those obtained for measurements of interleukin- la were obtained: while exposure to nicotinamide alone did not significantly reduce interleukin- ip expression (upregulated by Poly-IC or BAK) at any concentration, and exposure to adenosine was modestly effective only at the highest concentrations, synergistic reduction of the upregulated interleukin- ip expression was found when the HCECs were exposed to a solution containing both nicotinamide and adenosine, in some cases, nearly to the level of the untreated controls.

[0113] Reference is now made to FIGs. 3A - 3D, which show results of measurements of expression of interleukin-6, as determined by qRT-PCR, for the Poly-IC model (FIGs. 3A and 3B) and for the BAK model (FIGs. 3C and 3D) on in vitro cultured HCECs. FIGs. 3A and 3C show results for exposure to solutions containing 0.0005% (w / v) nicotinamide, 0.001% (w / v) adenosine, or 0.0005% (w / v) nicotinamide + 0.0001% (w / v) adenosine, and FIGs. 3B and 3D show results for exposure to solutions containing 0.001% (w / v) nicotinamide, 0.0005% (w / v) adenosine, or 0.001% (w / v) nicotinamide + 0.0005% (w / v) adenosine. While the results were not as dramatic as those for interleukin- la and interleukin- ip, the same general trend can be seen, namely, in most cases, a synergistic effect was seen in the reduction of the expression of interleukin-6 (upregulated by Poly-IC or BAK) by a combination of nicotinamide and adenosine in both models of corneal epithelial cell inflammation.

[0114] Reference is now made to FIGs. 4A - 4D, which show reduction of expression of tumor necrosis factor a (henceforth "TNFa"), as determined by qRT-PCR, for the Poly-IC model (FIGs. 4A and 4B) and for the BAK model (FIGs. 4C and 4D) . FIGs. 4A and 4C show resultsfor exposure to solutions containing 0.0005% (w / v) nicotinamide, 0.001% (w / v) adenosine, or 0.0005% (w / v) nicotinamide + 0.0001% (w / v) adenosine, and FIGs. 4B and 4D show results for exposure to solutions containing 0.001% (w / v) nicotinamide, 0.0005% (w / v) adenosine, or 0.001% (w / v) nicotinamide + 0.0005% (w / v) adenosine. The same general trend was seen for exposure to TNFa as for the interleukins that were tested: the reduction in TNFa (upregulated by Poly-IC or BAK) was significantly greater when the irritated cells were exposed to a mixture of nicotinamide and adenosine than would have been expected from an additive combination of the individual activities.

[0115] In summary, the in vitro experiments clearly show that a combination of nicotinamide and adenosine is effective at reducing the expression of genes associated with corneal cell irritation and inflammation, even when the nicotinamide and adenosine were present in the mixture at concentrations at which each component individually was not effective. The concentrations of the components in the nicotinamide / adenosine composition disclosed herein are at least an order of magnitude lower than the concentrations of these components in eye drop compositions known in the art [4,7] .Example 8In vivo studies of use of adenosine - nicotinamide compositions for treatment of an atropine- induced dry eye rabbit model

[0116] As a test of the efficacy of the formulation disclosed herein, an in vivo clinical experiment using an animal model of Dry Eye Syndrome was performed. The experiments were performed at Adgyl Life Sciences, Bangalore, India.

[0117] A cohort of 33 male New Zealand white rabbits of average weight of ~2.5 kg was divided into six groups. Three were left untreated; in the remainder, DES was induced by application of atropine three times daily starting six days prior to the commencement of treatment; the application of atropine continued throughout the course of the experiment. In order to provide a baseline, six of the animals in which DES had been induced were left untreated. Of the remainder, 12 were treated with a test formulation, six each with the formulations given in Examples 1 and 2 above. In order to provide a comparison with the efficacy of treatments known in the art, the remaining 12 animals were treated with a reference formulation: six were treated with an aqueous solution of 2.5% (w / v) glycerol, 0.15% (w / v) Carbomer 941, and 0.15% sodium hyaluronate (henceforth "LO2A"), and six withprednisolone, which is well-known in the art as an anti-inflammatory control substance [8], Treatment was performed for three weeks.

[0118] The eyes of the experimental animals were examined by slit lamp examination, Lissamine Green staining (after washout of fluorescein), tear secretion measurement via a modified Schirmer test, and taking of corneal photographs on days 0, 1, 14, and 21 of the trial. The test or reference formulation was applied topically 30 min after application of atropine.

[0119] Reference is now made to FIGs. 5A and 5B, which present results of Schirmer's Test measurements of tear secretion in the left and right eyes, respectively, of the animals used in the study. Results for untreated control animals are shown as black bars; results for animals in which DES was induced by application of atropine but were otherwise untreated are shown as bars with a checkerboard pattern; results for animals treated with the formulation given in Examples 1 and 2 above are shown as black bars with horizontal and vertical white stripes, respectively; results for animals treated with LO2A are shown as bars with diagonal stripes; and results for animals treated with prednisolone are shown as bars with a diamond pattern. Statistically significant differences (p < 0.05) from the results for the animals in which DES was induced but were otherwise untreated, as determined by a two-way ANOVA calculation followed by a Bonferroni multiple comparison test, are indicated by asterisks. As can be seen, treatment with the compositions of the invention disclosed herein produced statistically significant improvement in tear production relative to the untreated controls by Day 14 of the treatment period, and gave results comparable to treatment with LO2A or prednisolone.

[0120] Reference is now made to FIGs. 6A and 6B, which present results of TBUT measurements of the left and right eyes, respectively, of the experimental animals. The patterns on the bars and the indications of statistically significant results are as given in FIGs. 5A and 5B. As can be seen from the graphs, statistically significant improvement in the TBUT time relative to the untreated animals was observed within two weeks of commencement of treatment. After three weeks of treatment, the TBUT score was comparable to that of the naive animals.

[0121] Reference is now made to FIGs. 7A and 7B, which present Lissamine Green staining scores for the left and right eyes, respectively, of the experimental animals. The patterns on the bars and the indications of statistically significant results are as given in FIGs. 5A and 5B. A statistically significant reduction in the Lissamine Green score was observed within two weeks of commencement of treatment. The reduction in the Lissamine Green score resultingfrom treatment with the compositions of the instant invention was comparable to or better than that of the L02A composition known in the art.REFERENCES

[0122] [1] (a) Mayo Clinic Web Page "Dry Eyes" (https: / / www.mayoclinic.org / diseases- conditions / dry-eyes / symptoms-causes / syc-20371863); (b) United States National Eye Institute Web Page "Dry Eye" (https: / / www.nei.nih.gov / learn-about-eye-health / eye-conditions-and- diseases / dry-eye).

[0123] [2] Spinozzi, E.; Baldassari, C.; Acquaticci, L.; Del Bello, F.; Grifantini, M.; Cappellacci, L.; Riccardo, P., "Adenosine Receptors as Promising Targets for the Management of Ocular Diseases," Med. Chem. Res. 2021, 30, 353 - 370.

[0124] [3] Alio, J. L.; Ayala, M. J.; Mulet, E.; Artola, A.; Bellot, J. L.; Ruiz-Moreno, J. M., "Treatment of Experimental Acute Corneal Inflammation with Inhibitors of the Oxidative Metabolism," Ophthalmic Res. 1993, 25, 331 - 336.

[0125] [4] Shrestha, R.; Khadka, A.; Singh, N., "An Experimental Study to Evaluate the Effects of Adenosine on Intraocular Pressure in Conscious Albino Rabbits," Medical Journal ofShree Birendr a Hospital, 2016, 15, 36 - 42.

[0126] [5] Meng, Y.-F.; Pu, Q.; Dai, S.-Y.; Ma, Q.; Li, X.; Zhu, W., "Nicotinamide Mononucleotide Alleviates Hyperosmolarity-Induced IL-17a Secretion and Macrophage Activation in Corneal Epithelial Cells / Macrophage Co-Culture System," J. Inflamm. Res. 2021, 14, 479 - 493.

[0127] [6] I .ee, D.; Tomita, Y.; Shinojima, A.; Ban, N.; Yamaguchi, S.; Nishioka, K.; Negishi, K.; Yoshino, J.; Kurihara, T., "Nicotinamide Mononucleotide, a Potential Future Treatment in Ocular Diseases. Graefes Arch. Clin. Exp. Ophthalmol. 2024, 262, 689 - 700.

[0128] [7] Li, Z.; Duan, H; Li, W.; Jia, Y.; Zhang, S.; Zhao, C.; Zhou, Q.; Shi, W., "Nicotinamide Inhibits Corneal Endothelial Mesenchymal Transition and Accelerates Wound Healing," Exp. Eye Res. 2019, 184, 227 - 233.

[0129] [8] (a) King, J. H.; Weimer, J. R., "Prednisone (Meticorten) and Prednisolone (Meticortelone) in Ophthalmology: Experimental and Clinical Studies," AMA Arch. Ophthalmol. 1955, 54, 46 - 54. (b) Newman-Casey, P.A.; Woodward, M.A.; Niziol, L.M.; Lee, P.P.; De Lott, L.B., "Brand Medications and Medicare Part D: How Eye Care Providers' Prescribing Patterns Influence Costs," Ophthalmology 2018, 125, 332 - 339. (c) MedlinePlus[Internet], Bethesda (MD): National Library of Medicine (US); "Prednisolone Ophthalmic," [updated 9 May 2017; cited 12 Nov 2024]; available from: https: / / medlineplus.gov / druginfo / meds / a682794.html.

Claims

CLAIMSWe claim:

1. A humectant eye drop composition, wherein said eye drop composition comprises an aqueous solution comprising adenosine and nicotinamide.

2. The humectant eye drop composition according to claim 1, wherein said eye drop composition comprises adenosine and nicotinamide in concentrations that together demonstrate synergistic reduction of expression of at least one substance selected from the group consisting of interleukin- la, interleukin- ip, interleukin-6, and tumor necrosis factor a.

3. The humectant eye drop composition according to claim 2, wherein at least one of said adenosine and said nicotinamide is present in a concentration which, when applied alone, is insufficient to produce statistically significant (p < 0.05) reduction of expression of at least one substance selected from the group consisting of interleukin- la, interleukin- ip, interleukin-6, and tumor necrosis factor a.

4. The humectant eye drop composition according to claim 1, wherein said composition is isotonic.

5. The humectant eye drop composition according to claim 1, wherein said composition is characterized by non-Newtonian rheological properties.

6. The humectant eye drop composition according to claim 1, wherein said aqueous solution comprises adenosine, nicotinamide, a polymer characterized by an average molecular weight of >10,000 Da, and acid or base as necessary to adjust a pH of said aqueous solution to a value of 6.5 - 7.5.

7. The humectant eye drop composition according to claim 6, wherein said polymer is selected from the group consisting of hyaluronate and carbomer.

8. The humectant eye drop composition according to claim 7, wherein said composition comprises 0.2 - 0.6% (w / v) Carbomer 981.

9. The humectant eye drop composition according to claim 1, wherein said aqueous solution comprises adenosine and nicotinamide in a ratio of 1 :5 - 5: 1 (w / v).

0. The humectant eye drop composition according to claim 1, wherein said eye drop composition is characterized by an adenosine concentration of 0.01% - 0.5% (w / v) and a nicotinamide concentration of 0.01% - 0.5% (w / v).

11. The humectant eye drop composition according to claim 10, wherein said eye drop composition is characterized by an adenosine concentration of 0.01% - 0.05% (w / v) and a nicotinamide concentration of 0.01% - 0.05% (w / v).

12. The humectant eye drop composition according to claim 10, wherein said eye drop composition further comprises 0.2 - 0.6% (w / v) Carbomer 981.

13. The humectant eye drop composition according to claim 1, wherein said eye drop composition comprises an aqueous solution comprising 0.025% (w / v) adenosine, 0.05% (w / v) nicotinamide, and sufficient acid or base to adjust the pH to a value of 6.5 - 7.5.

14. The humectant eye drop composition according to claim 13, wherein said eye drop composition further comprises 0.20% (w / v) Carbomer 981.

15. The humectant eye drop composition according to claim 13, wherein said eye drop composition further comprises 0.15% (w / v) sodium hyaluronate, said hyaluronate characterized by a molecular weight of 1500 - 1800 kDa.

16. The humectant eye drop composition according to claim 1, wherein said eye drop composition further comprises at least one excipient selected from the group consisting of stabilizers, buffers, antioxidants, and combinations and mixtures thereof.

17. The humectant eye drop composition according to claim 1, wherein said eye drop composition further comprises a preservative.

18. The humectant eye drop composition according to claim 1, wherein said eye drop composition is preservative-free.

19. The humectant eye drop composition according to claim 1, wherein said eye drop composition further comprises a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof.

20. The humectant eye drop composition according to claim 19, wherein said composition is characterized by a trehalose concentration equivalent to 3 - 6% (w / v) anhydrous trehalose.

21. The humectant eye drop composition according to claim 20, wherein said composition comprises an aqueous solution comprising 0.01% - 0.05% (w / v) adenosine; 0.01% - 0.05% (w / v) nicotinamide; 0.2 - 0.6% (w / v) Carbomer 981; a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof in a concentration equivalent to 3% anhydrous trehalose; and sufficient acid or base to adjust the pH to a value of 6.5 - 7.5.

22. The humectant eye drop composition according to claim 21, wherein said composition comprises an aqueous solution comprising 0.01% - 0.05% (w / v) adenosine; 0.01% - 0.05% (w / v) nicotinamide; a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof in a concentration equivalent to 3%; 0.6% (w / v) Carbomer 981; 0.64% NaCl; a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof in a concentration equivalent to 3% anhydrous trehalose; and sufficient acid or base to adjust the pH to a value of 6.5 - 7.5.

23. The humectant eye drop composition according to claim 1, wherein said eye drop composition further comprises a pharmaceutically effective concentration at least one pharmacologically active agent.

24. The humectant eye drop composition according to claim 23, wherein said eye drop composition further comprises at least one substance appropriate for use with said pharmacologically active agent, said at least one substance selected from the group consisting of stabilizers, antioxidants, buffers, and combinations and mixtures thereof.

25. The humectant eye drop composition according to claim 23, wherein said eye drop composition further comprises a preservative.

26. The humectant eye drop composition according to claim 23, wherein said eye drop composition is preservative-free.

27. The humectant eye drop composition according to claim 1, wherein said eye drop composition consists of an aqueous solution consisting of adenosine, nicotinamide, sufficient acid or base to adjust the pH to a value of 6.5 - 7.5, and at least one component selected from the group consisting of Carbomer 981, sodium hyaluronate, hyaluronic acid, and trehalose.

28. The humectant eye drop composition according to claim 28, wherein said eye drop composition consists of an aqueous solution consisting of 0.025% (w / v) adenosine, 0.05% (w / v) nicotinamide, sufficient acid or base to adjust the pH to a value of 6.5 - 7.5, and a component selected from the group consisting of 0.20% (w / v) Carbomer 981 and 0.15% (w / v) sodium hyaluronate.

29. The humectant eye drop composition according to claim 28, wherein said eye drop composition consists of an aqueous solution consisting of 0.025% (w / v) adenosine; 0.05% (w / v) nicotinamide; a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof in a concentration equivalent to3% anhydrous trehalose; sufficient acid or base to adjust the pH to a value of 6.5 - 7.5; and a component selected from the group consisting of 0.20% (w / v) Carbomer 981 and 0.15% (w / v) sodium hyaluronate.

30. The humectant eye drop composition according to claim 28, wherein said eye drop composition consists of an aqueous solution consisting of 0.025% (w / v) adenosine; 0.05% (w / v) nicotinamide; a component selected from the group consisting of anhydrous trehalose, trehalose dihydrate, and mixtures and combinations thereof in a concentration equivalent to 3% anhydrous trehalose; sufficient acid or base to adjust the pH to a value of 6.5 - 7.5; 0.64% NaCl; and 0.6% (w / v) Carbomer 981.

31. A method of treatment of Dry Eye Syndrome, wherein said method comprises applying topically to an eye of a patient in need the humectant eye drop composition according to any one of claims 1 - 30.

32. The method according to claim 31, wherein said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Schirmer's Test Score is observed.

33. The method according to claim 31, wherein said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Tear Film Breakup Time (TBUT) is observed.

34. The method according to claim 31, wherein said method comprises applying said humectant eye drop composition 1 - 4 times daily.

35. The method according to claim 31, wherein said method comprises applying said humectant eye drop composition 1 - 4 times daily for a period of three weeks.

36. A method of relief of symptoms of Dry Eye Syndrome, comprising applying topically to an eye of a patient in need the humectant eye drop composition according to any one of claims 1 - 30 until at least partial relief of said symptoms is observed.

37. The humectant eye drop composition according to any one of claims 1 - 30 for use in a method of treatment of Dry Eye Syndrome, wherein said method comprises applying said humectant eye drop composition topically to at least one eye of a patient in need.

38. The humectant eye drop composition according to claim 37, wherein said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Schirmer's Test Score is observed.

39. The humectant eye drop composition according to claim 37, wherein said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Tear Film Breakup Time (TBUT) is observed.

40. The humectant eye drop composition according to claim 37, wherein said method comprises applying said eye drop composition 1 - 4 times daily for a period of three weeks.

41. The humectant eye drop composition according to any one of claims 1 - 30 for use in a method of treatment of symptoms of Dry Eye Syndrome, wherein said method comprises applying said eye drop composition topically to at least one eye of a patient in need until at least partial relief of said symptoms is obtained.

42. Use of the humectant eye drop composition according to any one of claims 1 - 30 in a method of treatment of Dry Eye Syndrome, wherein said method comprises applying topically to at least one eye of a patient in need said eye drop composition.

43. The use according to claim 42, wherein said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Schirmer's Test Score is observed.

44. The use according to claim 42, wherein said method comprises applying said humectant eye drop composition until a statistically significant improvement in a Tear Film Breakup Time (TBUT) is observed.

45. The use according to claim 42, wherein said method comprises applying said humectant eye drop composition 1 - 4 times daily.

46. The use according to claim 42, wherein said method comprises applying said humectant eye drop composition 1 - 4 times daily for a period of three weeks.

47. Use of the humectant eye drop composition according to any one of claims 1 - 30 in a method of treatment of symptoms of Dry Eye Syndrome, wherein said method comprises applying said eye drop composition topically to at least one eye of a patient in need until at least partial relief of said symptoms is obtained.

48. The use according to claim 47, wherein said method comprises applying said humectant eye drop composition 1 - 4 times daily.

49. The use according to claim 47, wherein said method comprises applying said humectant eye drop composition 1 - 4 times daily for a period of three weeks.

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