Ophthalmic formulations and related methods

Abstract

The present disclosure relates to an eye drop suspension for dry eye and other eye indications that provides long-lasting benefits to the eye.The present disclosure provides a method for increasing lipid layer thickness and lubricating the eye.The present disclosure also provides a method for maintaining the integrity of the tear film layer of the eye, increasing lipid layer thickness of the eye, and a method for reshaping or building one or more layers of the tear film of the eye.

Description

[Technical field]

[0001] The present disclosure provides long-lasting ophthalmic suspensions for the ophthalmic treatment of dry eye and other ophthalmic indications. The ophthalmic suspensions described herein provide dry eye relief that lasts 2-10 hours longer for the eye than currently available marketed products. [Background technology]

[0002] The tear film is produced by the secretions of various glands in the eye during normal blinking. These secretions or components constitute a healthy and stable tear film. The aqueous portion of the tears is produced primarily by the lacrimal glands activated by blinking. The outer tear layer is a lipid layer excreted primarily from the meibomian glands located in the eyelids during blinking. The lipid layer provides a protective layer over the tear film designed to reduce evaporation of the aqueous solution of the tear film. Thinning the lipid layer increases the evaporation of the aqueous layer, resulting in dry eye on the corneal surface during blinking. The tear film rate of evaporation in such dry eye patients increases by 30% to 38% at relative humidities below 50%. This conglomerate of secretions from the lacrimal and meibomian glands, along with the eyelids providing a wiper effect from normal blinking, provides a normal, long-lasting, and stable tear film for the eye. Normal component production repairs and replaces the tear film, but loss of critical components due to dysfunction or lack of secretion leads to tear film instability and rapid loss of tear film structure, resulting in dry eye.

[0003] The tear film protects, lubricates, nourishes, and cleanses the ocular surface. Its key role is to prevent dehydration of the underlying corneal and conjunctival tissues and to provide a smooth surface during blinking. The tear film serves a variety of functions. One of the most important functions of the tear film is to reduce evaporation from the ocular surface, thereby preventing drying of the cornea and conjunctiva. If the tear film is not kept adequately hydrated and lubricated, it can cause epithelial cell damage and inflammation. This can result in severe discomfort and pain, and even severe corneal damage. The tear film lubricates the eyelids, allowing for a smooth and comfortable blink. If the corneal and eyelid surfaces are not sufficiently smooth or lubricated, abrasive damage can occur, which can cause problems similar to the corneal and conjunctival dryness described above, and is described as lid wiper epitheliopathy. Because the cornea is an avascular construct, the tear film contains nutrients that nourish the corneal epithelium and removes cellular waste and debris. It also supplies oxygen to the corneal and conjunctival epithelium and removes carbon dioxide. When the cornea becomes malnourished, blood vessels can grow there to provide it with the necessary nutrients. These blood vessels can interfere with vision and are characteristic of very severe dry eye conditions.

[0004] The tear film contains antibacterial and antiviral substances that protect the eye from infection. Tears are buffered and can neutralize mild acids and bases, allowing the eye to tolerate instillations of substances with a pH range of 6.6 to 7.8. The tear film aids vision by refracting (bending) light and forming a smooth, clear optical surface on the cornea (thereby eliminating microscopic surface irregularities in the corneal epithelium). The refractive index of the tear film is 1.3345 to 1.3360 (the refractive index of air is 1.0).

[0005] The tear film is understood to be composed of five distinct layers, each of which serves an important function in maintaining the tear film: the outer (oily) lipid layer, which lubricates eyelid movement and reduces evaporation from the aqueous layer. The next layer, which constitutes the largest portion of the tear film, is the aqueous layer, which provides hydration and nutrients to the avascular cornea while removing cellular by-products and debris. Finally, the inner mucin layer, which is excreted by the cornea, reduces the surface tension of the tear film, allowing it to spread evenly across the ocular surface. The outer stromal layer is located between the lipid and aqueous layers. The inner stromal layer is located between the aqueous and mucin layers.

[0006] Normally, continuous basal secretion of tear components throughout the day and night ensures that the tear film is adequately lubricated and provides a protective environment for the most part. However, the formation and maintenance of the tear film does not simply depend on the production of sufficient tear fluid. The quality (i.e., composition) of the tear fluid and the blinking process also play important roles in maintaining a healthy tear film.

[0007] Normal tears maintain the correct balance of lipid, aqueous, and mucin components during blinking to form a stable and protective tear film. During blinking, the tear film thins due to evaporation, and lipid molecules from the outer layer begin to migrate through the aqueous layer toward the mucin layer. The aqueous portion of the tears also exchanges on the eye at a rate of about 16% by volume per minute, where the lipid layer exchanges on the eye at a rate of about 2% per minute. Contamination of the mucin layer with the lipid layer increases the surface tension of the tear film, eventually causing it to rupture (break down), beading up and forming dry areas on the corneal surface. Subsequent blinks usually repair this rupture by removing the lipid contamination from the mucin layer and restoring the normal aqueous layer. However, repeated ruptures cause loss of the mucin layer, which shows staining when observed with fluorescein.

[0008] Age, disease, glandular dysfunction, medications, preservatives in ophthalmic preparations, and contact lens wear can result in imbalance of tear film components, inability to blink properly, problems with lid closure and sealing, and an unstable tear film that can break up within a few seconds (i.e., before the next blink). When this occurs, the break-up time of the tear film becomes shorter than the blink interval (whether due to an adequate tear film or insufficient blinking), resulting in dry spots on the ocular surface of the eye, which is the first stage in the development of ocular surface disease or dry eye. Ideally, the break-up time should be equal to or longer than the normal blink interval.

[0009] Loss of tear film structure leads to dry eye, an ophthalmic disease currently affecting over 350 million people worldwide, including over 50 million in the United States, representing 15% of the U.S. population. Discomfort resulting from dry eye conditions includes dryness, grittiness, burning, pain, scratching, and foreign body reactions. The degree of discomfort varies depending on the subject and the condition of the subject. The primary cause of dry eye is loss of the lipid layer due to dysfunction of the meibomian glands, which is estimated to account for 86% of all dry eye cases. Changes in composition are reflected in the loss of meibum produced as a thick / semi-solid material and / or the glands that produce it. Also, little is known about the importance of the various components in the formation of the lipid layer, although differences have been discussed by many authors. The importance of the lipid layer in maintaining the tear film has been well studied, showing that it is important in preventing loss of the aqueous layer due to evaporation. Thinning of the lipid layer is thought to enhance the symptoms of dry eye caused by evaporation of the aqueous component of the tear film.

[0010] The most common treatment for dry eye involves the temporary relief of dry eye symptoms by topical application of artificial tear substances that provide liquid volume to the ocular surface and adjacent tissues, e.g., eyelids, cornea. Typical commercially available tear replacement compositions include water-soluble polymer solutions. Examples of such solutions include saline solutions of polyvinyl alcohol, hydroxypropyl methylcellulose, or carboxymethylcellulose. U.S. Pat. No. 4,421,748 teaches artificial tear compositions that include a viscosity modifier, such as a hypotonic aqueous solution of lecithin and a solution of water-soluble cellulose. The aqueous humor tear film spreads over the ocular surface and maintains a lubricated and moist ocular surface. It is also known that dehydration of water from the eye causes discomfort. Additionally, compositions intended for dry eye treatment are available on the market. The commercially available compositions are primarily aqueous materials that replenish the tear film by adding a film of water-soluble polymers on the ocular surface. These films are short-lived and provide limited relief.

[0011] Many improved compositions for dry eye treatment are disclosed in U.S. Patent Nos. 4,914,088, 5,278,151, 5,294,607, 5,578,586, and 9,161,905, each of which is incorporated herein by reference for its teachings on forming an oil film on the surface of the eye, including compositions and applications.U.S. Patent No. 4,914,088 teaches the use of certain charged phospholipids for treating dry eye symptoms.It is believed that adding charged phospholipids to the eye helps to replicate the tear film that occurs naturally in the eye.According to the patent, the phospholipid composition, preferably in the form of an aqueous emulsion, is applied topically to the eye, where it is believed to disperse on the ocular surface and form a film that replicates the lipid layer that is formed by the diffusion of natural lipids that are mainly discharged from the meibomian gland during blinking. Since phospholipids carry a net negative charge when applied to the eye, it is believed that the aligned molecules repel each other, preventing the formation of complex aggregates, thereby creating a stable phospholipid interface between the lipid and aqueous phase. The patent theorizes that the membrane formed from the charged phospholipids helps form a barrier membrane and reduces the evaporation of the aqueous layer, thereby preserving the tear film. Others theorize that phospholipids also function as surfactants that maintain emulsion stability.

[0012] The above-mentioned US Patents 5,278,151, 5,294,607, 5,578,586, 9,279,095, and 9,375,401 disclose further improvements in dry eye treatment. In these patents, the dry eye treatment composition of US Patent 4,914,088 is improved by adding an oil, preferably a non-polar oil such as mineral oil composed of a hydrocarbon component, to the eye treatment composition. The oil is added to improve the performance of the dry eye treatment composition by increasing the longevity of the tear film formed on the ocular surface as a result of the oil film formed on the ocular surface, and functions as an evaporation barrier, i.e., by providing and / or thickening a dehydration barrier (oil layer) on the outer surface of the tear film. In this way, the oil increases the effectiveness of the dry eye treatment solution and reduces the variability in performance between subjects. It also supplements the oil supplied by the meibomian glands, which in many cases of dry eye do not supply enough oil to provide an adequate lipid tear film. A preferred embodiment disclosed in the above referenced patent is a dry eye treatment composition comprising a meta-stable oil-in-water emulsion in which the aqueous phase contains a charged phospholipid which is believed to function as an emulsifier and as a surfactant to aid in the spreading of the oil onto the eye to form a non-blurring membrane bond of the oil to the aqueous layer of the tear film. The emulsion is desirably "meta" stable so that when the emulsion is applied to the eye, it rapidly breaks down and spreads over the ocular surface upon first contacting the ocular environment.

[0013] U.S. Patent Nos. 5,371,108, 5,278,151 and U.S. Patent Application Publication No. 2016 / 03389952 to Korb teach methods or formulations for making emulsions or gels containing oils and waxes to form a tear film on the ocular surface to increase the residence time of the oil. However, wax-containing gels have not been manufactured and marketed because of the difficulty of homogenizing the wax in a way that does not induce visual blurring beyond the tolerance of most consumers. In particular, high pressure steam sterilization (autoclaving) to sterilize wax-containing formulations results in an increase in particle size, which causes irritation and blurred vision. Gels are semi-solid formulations with high viscosity. In contrast, the present disclosure relates to metastable emulsions that behave as flowable liquids at room temperature. Emulsions behave as liquids and as such do not exhibit a static internal structure or have a high viscosity. Korb also utilizes preservatives at levels known to be toxic to corneal cells upon administration and does not disclose vehicles that exhibit extended residence times.

[0014] Many ophthalmic formulations and compositions for use focus on the use of zeta potential, as described in WO2016209555, WO2015057847, WO2011098578, WO2011084509, WO03053405, US2012328702, US2012225834, and U.S. Patent Nos. 7,060,285, 9,827,191, 8,298,569, 7,893,040, 7,834,172, and 10,137,083, which are incorporated by reference herein for their teachings of the use of zeta potential.

[0015] Current marketed products, including oil and water emulsion products, often supplement one or more layers of the tear film via various combinations of oils, aqueous solutions, and mucomimetics (mucosal stimulants). Although these lipid emulsions provide sufficient lubrication and prevent drying, they fall short in terms of their ability to remain on the eye and provide sustained relief, which is the most desired clinical outcome. In addition, these compositions are unable to completely remodel the tear film, resulting in the layers losing their natural stability on the ocular surface and thus providing limited relief due to their on-eye residence time being less than 30 minutes. Without connectivity to each subsequent layer of the film, the lipid, water, and mucin layers, whether natural, artificial, or some combination thereof, tend to develop in too short a time to provide sustained comfort from dry eye symptoms. Figure 1 provides a close-up view of the eye and components of the layers and interfaces of the tear film. A normal tear film is 3-6 μM thick. The two inserts with lines on the tear film show a close-up view of the lipid / water interface and the water / mucin interface. The third inset shows the thinning of layers and interfaces associated with dry eye. In particular, it shows the thinning of (i) the aqueous layer, (ii) the unbound mucin layer, and (iii) the bound mucin layer on the surface of the corneal epithelial cells. Existing products do not stabilize the different layers and interfaces of the tear film, including the lipid layer. Therefore, existing products do not form a stable lipid layer and do not provide long-term benefits. Summary of the Invention

[0016] The tear film of the human eye contains three distinct layers, and recent learning and research has determined that two additional layers of the tear film are the stromal layers. These stromal layers of the tear film are from other glands in the eyelid that are different from the lacrimal glands and meibomian glands of the eyelid. These stromal layers excrete components that provide a healthy, normal, and stable tear film. These glands include the Krause, Wolfring, Moll, and Heine glands, which secrete wax, wax esters, and additional surfactants and chemicals that enhance the Velcro effect of the interface between the tear film layers, as well as thickening the tear film to reduce tear film evaporation. The two stromal layers each play an important function in maintaining the tear film. Overall, the tear film contains five layers with an outer (oily) lipid layer excreted (secreted) by the meibomian glands. The first stromal layer is excreted by the meibomian and Claus, Wolffring, Mohr, and Heine glands and contains anionic polar phospholipids (i.e., linking the lipid layer to the aqueous layer), wax esters, and surfactants (i.e., thickening and enhancing lipid and stromal connections), which link the lipid layer to the aqueous layer of the tear film and maintain a stable tear film. The next layer, which constitutes the largest portion of the tear film, is the aqueous (watery) layer, which hydrates and provides nutrients to the avascular cornea while removing cellular by-products and debris. The second stromal layer, excreted (excreted) by the Claus, Wolffring, Mohr, and Heine glands, is made of wax esters and surfactants, which concentrate water and enhance connections to corneal-secreted mucins that link the aqueous layer to the cornea and maintain a stable tear film. Finally, the inner mucin layer excreted by the cornea adheres to the cornea and reduces the surface tension of the tear film, allowing it to spread evenly across the ocular surface. In combination with the aqueous secretions of the lipid-excreting meibomian and lacrimal glands, waxes and wax esters and surfactants that act as lip wipers on the eyelids during normal blinking, a normal, stable, and sustained ocular tear film is formed.Thus, the addition of wax esters such as beeswax and their partial hydrolysis products and their normal distribution throughout the various phases of the suspension has the same effectiveness in improving the efficacy of the composition by allowing the lubricating elements to remain on the eye for an extended period of time similar to a normal tear film.

[0017] Disclosed herein is an eye drop suspension that mimics the natural tear film, which includes three distinct layers and two stromal layers, and reconstructs or otherwise increases the thickness of the eye drop layer over time, thereby reducing tear film evaporation and maintaining normal tear structure in the eye. The eye drop suspension provided herein can be implemented as a replacement for each tear film layer (lipid, aqueous, stromal and mucin), enhancing the tear film, improving the natural function of the tear film, maintaining significantly longer residence time in the eye, and improving patient comfort. By providing a longer lasting effect on the eye, fewer applications or drops are required to be used by patients in need of treatment. By replacing the lipid (outer) layer, enhancing the aqueous (middle) layer, mimicking the mucin (inner) layer, and incorporating a stromal layer, the eye drop suspension of the present invention mimics natural tears and functions as a true artificial tear.

[0018] Emulsified oil-in-water suspensions containing wax esters or eye drop suspensions are provided that contain an appropriate combination of wax esters, surfactants, and other ingredients provided herein to provide a tear film that mimics the body's natural tear film and maintains its structure on the eye for an extended period of time.

[0019] According to one aspect, the present disclosure provides an ophthalmic suspension comprising: i) an aqueous phase comprising water and one or more components selected from the group consisting of at least one wax ester, at least one anionic polar surfactant, at least one nonionic surfactant, at least one salt, and at least one phosphate; and ii) an oil phase comprising at least one mineral oil and, optionally, at least one wax ester. According to one embodiment, the wax ester exhibits an average particle size measured via a Microtrac particle analyzer. The wax ester exhibits an average particle size of at least about 2.0 microns. According to one embodiment, the wax ester exhibits an average particle size distribution of at least about 2.0 microns to about 20.0 microns. According to one embodiment, the wax ester exhibits an average particle size distribution of at least about 5.0 microns. According to one embodiment, the ophthalmic suspension has an osmolality of about 245 mOsmol / kg to about 315 mOsmol / kg. According to one embodiment, the ophthalmic suspension is formulated as a free-flowing emulsified suspension at about 30° C. According to one embodiment, the wax ester is present at a concentration of about 0.8% to about 1.2% by weight. According to one embodiment, the wax ester is natural beeswax. According to one embodiment, the wax ester is synthetic beeswax. According to one embodiment, the ophthalmic suspension exhibits a negative zeta potential of about −60 mV to about −110 mV. According to one embodiment, the ophthalmic suspension exhibits an ion mobility of about −5.9 (μms) / (V / cm) to about −7.4 (μms) / (V / cm). According to one embodiment, the oil is a mixture of light mineral oil and heavy mineral oil. According to one embodiment, the light mineral oil has a viscosity of about 3.0 mm at 40° C. 2 s ‐1 from about 34.4 mm 2 s ‐1 Heavy mineral oils have a kinematic viscosity of about 34.5 mm at 40°C. 2 s ‐1 From about 150 mm 2 s ‐1According to one embodiment, the ophthalmic suspension further comprises an anionic polar surfactant comprising a mixture of a polysorbate nonionic surfactant at a concentration of about 0.35 to about 0.45% by weight and an anionic polar dimyristoyl phosphatidylglycerol at a concentration of about 0.35 to about 0.55% by weight. According to one embodiment, the ophthalmic suspension is packaged as a sterile multi-use or sterile single-use container. According to one embodiment, the ophthalmic suspension is packaged in a multi-dose non-preserved (MDNP) container or a container comprising at least one preservative. According to one embodiment, the ophthalmic suspension increases the lipid layer thickness by at least 20 nanometers 5 minutes after administration. According to one embodiment, the ophthalmic suspension increases the lipid layer thickness by at least 20 nanometers 60 minutes after administration. According to one embodiment, the ophthalmic suspension increases the lipid layer thickness by at least 25 nanometers net of control 5 minutes after administration. According to one embodiment, the ophthalmic suspension increases the lipid layer thickness by at least 20 nanometers 4 hours after administration. According to one embodiment, the ophthalmic suspension increases the lipid layer thickness by at least 25 nanometers net of the control 4 hours after administration.

[0020] According to another aspect, a method for increasing lipid layer thickness is provided. The method comprises administering an ophthalmic suspension as provided herein to an eye of a patient in need of treatment. According to one embodiment, the lipid layer thickness increases from baseline by at least 20 nm within 5 minutes of administration. According to one embodiment, the lipid layer thickness increases from baseline by at least 20 nm 4 hours after administration. According to one embodiment, the lipid layer thickness increases from baseline by at least 25 nm 4 hours after administration.

[0021] According to one aspect, a method of lubricating an eye is provided. The method comprises administering an ophthalmic suspension as provided herein to an eye of a patient in need of treatment. According to one embodiment, the ophthalmic suspension reforms or reconstructs one or more layers of the tear film of the eye and maintains the integrity of the tear film for 60 minutes or more. According to one embodiment, the ophthalmic suspension reforms or reconstructs one or more layers of the tear film of the eye and maintains the integrity of the tear film for 90 minutes or more. According to one embodiment, the ophthalmic suspension reforms or reconstructs one or more layers of the tear film of the eye and maintains the integrity of the tear film for 120 minutes or more. According to one embodiment, the ophthalmic suspension reforms or reconstructs one or more layers of the tear film of the eye and maintains the integrity of the tear film for 150 minutes or more.

[0022] According to one aspect, a method of alleviating symptoms of dry eye is provided, comprising administering to an eye of a patient in need of treatment an ophthalmic suspension provided herein.

[0023] According to one aspect, a method for maintaining the integrity of the tear film layer of the eye is provided, which increases the thickness of the lipid layer of the eye. The method comprises administering an ophthalmic suspension provided herein to an eye of a patient in need of treatment. According to one embodiment, the integrity of the tear film is maintained and the lipid layer thickness is increased by at least 20 nm 60 minutes after administration.

[0024] According to one embodiment, a method for reconstructing or remodeling one or more layers of the tear film of an eye is provided. The method comprises administering an ophthalmic suspension provided herein to an eye of a patient in need of treatment. Upon administration, the ophthalmic suspension reconstructs or remodels one or more layers of the tear film of the eye. [Brief description of the drawings]

[0025] [Figure 1]FIG. 1 shows a close-up of the tear film identifying different regions. A normal tear film is 3-6 microns thick. The figure shows the lipid layer, lipid / aqueous interface, aqueous layer, aqueous / mucin interface, mucin layer, and cornea. Two insets show close-ups of the lipid / aqueous interface and the aqueous / mucin interface. The third inset shows the thinning of layers and interfaces associated with dry eye. In particular, the third inset shows the thinning of (i) the aqueous layer, (ii) the unbound mucin layer, and (iii) the bound mucin layer bound to the surface of corneal epithelial cells. Methods for evaluating the tear film are further provided in U.S. Patent Application Serial No. 16 / 708120 (U.S. Patent Publication No. 2020 / 0179281), the entire contents of which are incorporated herein by reference. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Although the following terms are believed to be well understood to those of ordinary skill in the art, the following definitions are provided to facilitate description of the presently disclosed subject matter.

[0027] As used herein, the terms "about" and / or "approximately" may be used with numerical values ​​and / or ranges. The term "about" is understood to mean a value close to the recited value. Alternatively, depending on the context, the term "about" may mean ±1 / 2 standard deviation, ±1 standard deviation, or ±2 standard deviations. Furthermore, the phrases "less than about [value]" or "greater than about [value]" should be understood in light of the definition of the term "about" provided herein. The terms "about" and "approximately" may be used interchangeably. Throughout this specification, numerical ranges are provided for specific quantities.

[0028] As used herein, the verb "comprise" and its conjugations as used in the specification and claims are used in an open-ended sense meaning that the items following the word are included but not excluding items not specifically mentioned.

[0029] As used herein, the word "comprise" or variations such as "comprises" or "comprising" are understood to imply the inclusion of a recited element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. The disclosure may "comprise," "consist of," or "consist essentially of" the steps, elements, and / or agents recited in the claims, as appropriate.

[0030] It should be further noted that the claims are drafted to exclude any optional elements. Accordingly, this statement is intended to serve as an antecedent basis for using exclusive terminology such as "solely," "only," and the like in connection with reciting claim elements or using a "negative" limitation.

[0031] As used herein, the term "wt %" means the amount based on the ophthalmic suspension vehicle, unless otherwise specified.

[0032] As used herein, the term "wax ester" refers to an ester of a fatty acid and a fatty alcohol. Wax esters can include a number of compounds with various carbon chain lengths. The wax esters provided herein can include long carbon chains. The wax esters provided herein can be present in solid particles that exhibit a melting point of about 60°C to about 100°C. The wax esters provided herein can be natural beeswax. Natural beeswax is also commercially available as Cera Alba or Cera Flava (white or yellow beeswax). The use of natural beeswax can include hydrocarbons as a component. During the preparation of one embodiment of the emulsion of the present disclosure, the wax esters can undergo hydrolysis to generate additional acids and / or alcohols as part of the process. The terms "wax ester dispersion" and "wax dispersion" can be used interchangeably.

[0033] As used herein, the term "particle size" refers to the size of wax ester particles, alone or in combination with one or more oils, phospholipids, surfactants, hyaluronic acid (HA), sodium hyaluronate, or any other ophthalmic suspension vehicle (vehicle component) provided herein.

[0034] The term "residence time" as used herein refers to the time (e.g., minutes or hours) that an ophthalmic suspension vehicle remains on the eye from a single application when assessing the level or amount of lipid layer thickness from the baseline of the eye.The lipid layer thickness can be measured by interferometry instrumentation to measure the residence time on the eye.

[0035] As used herein, the term "persistence" refers to an increase in residence time observed over a period of time compared to untreated eyes.

[0036] As used herein, the term "stability" refers to the time that the tear film maintains its structure between blinks.

[0037] As used herein, the term "tear film" refers to the entire protective coating provided to the eye, including that shown in FIG.

[0038] As used herein, the term "dry eye" refers to an ocular condition in which the tear film is unable to perform its lubricating function and may be caused by a lack of important components to form a stable tear film.

[0039] As used herein, the terms "light mineral oil" and "light mineral oil" may be used interchangeably and refer to low viscosity mineral oils as defined by the NF or USP formulas.

[0040] As used herein, the terms "heavy mineral oil" and "heavy mineral oil" may be used interchangeably and refer to variants of high viscosity mineral oil that meet the requirements of the NF or USP monographs for mineral oil.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0042] The present disclosure relates to ophthalmic suspensions and related methods. The ophthalmic suspensions are particularly suitable for increasing the lipid layer thickness of the eye relative to baseline lipid layer thickness. The ophthalmic suspensions provided herein form an artificial tear film (tear film) on the ocular surface of the eye, enhancing ocular lubrication while reducing evaporation. The ophthalmic suspensions remain on the eye and exhibit a significantly longer residence time than any currently available product on the market. The ophthalmic suspensions provided herein complement the interstitial binding properties, forming and thickening the tear film, as well as the discrete layer of the tear film. This results in a significant improvement in the duration of dry eye relief.

[0043] The ophthalmic suspension vehicle comprises an aqueous phase and an oil phase. The aqueous phase can comprise water and one or more wax esters, at least one anionic polar surfactant, at least one nonionic surfactant, at least one salt and at least one phosphate. The water used in the ophthalmic suspension vehicle provided herein can be purified water or ion-exchanged water. The oil phase can comprise at least one mineral oil, and optionally at least one wax ester. Thus, the at least one wax ester can be present in the aqueous phase, the oil phase, or both the aqueous phase and the oil phase. According to certain embodiments, the at least one wax ester is in either the aqueous phase or the oil phase.

[0044] The eye drop suspension provided herein can be formulated as an oil-in-water emulsion suspension.Emulsion suspension as the term used herein is a suspension that includes an aqueous phase and an oil phase that incorporates wax ester particulate components.Wax ester particles in aqueous phase tend to aggregate but are not soluble in water.The lack of solubility is due to the significant charge stabilization of wax ester particles.Wax ester particles in oil phase tend to aggregate or not mix with water.

[0045] When the emulsified suspension is applied to the eye as a standard drop, it differentiates rapidly, allowing for the rapid formation of an oil film on the corneal surface without the expulsion of excess oil by blinking. The emulsified suspension can differentiate within about 10 blinks, more preferably in less than about 1 minute after application to the eye. During and following differentiation of the emulsified suspension, the formation of the oil film is aided by the use of a combination of surfactants that help form the emulsified suspension and facilitate the spreading of the oil over the ocular surface as the emulsified suspension is broken down.

[0046] In contrast to emulsified eye drop suspensions, stable emulsions cannot rapidly differentiate when applied to the ocular surface. Emulsions are typically optically opaque due to the presence of two distinct phases. Thus, opaque emulsions on the ocular surface are prone to blurring. The duration of blurring depends on the time required for the emulsion to differentiate and form separate layers that replicate the tear film. Furthermore, emulsions are most easily applied to the eye as a standard solution from an eye dropper. The eye can hold a limited volume of fluid, less than 25 μL in volume. The 25 μL volume is substantially less than the volume of a standard drop. Thus, if the emulsion is stable and does not rapidly differentiate after application to the eye, excess emulsion will be expelled from the eye during blinking. Release of the emulsion from the eye releases the active ingredients of the treatment suspension from the eye before a long-lasting tear film is formed. Thus, the active ingredients may not be available in sufficient amounts to form the desired tear film.

[0047] The ophthalmic suspensions provided herein are free-flowing liquids at room temperature, e.g., between about 20° C. and about 30° C. The emulsified suspensions provided herein separate into an oil phase and an aqueous phase upon contact with the eye. The surface of the eye typically exhibits a temperature of about 32° C. to about 36° C.

[0048] According to certain embodiments, the ophthalmic suspensions provided herein include an oil-in-water emulsion. The oil-in-water emulsion includes at least one oil and water. The water can be purified water or deionized water. The oil used to form the oil-in-water emulsion can be derived from animals, plants, nuts, or other suitable sources. Oils derived from animals, plant seeds, and nuts are similar to fats and are primarily glycerides or fatty acids, and therefore contain a significant number of acid and / or ester groups that make the oil polar. Examples of these oils are safflower oil, corn oil, canola oil, whale oil, and seal oil, or chemically similar oils. Additional oils provided herein include vegetable oils such as castor oil, almond oil, myrrh oil, corn oil, peanut oil, canola oil, safflower oil, kola nut oil, light olive oil, bay leaf oil, or other generally recognized as safe (GRAS) oils that are listed as suitable for ophthalmic formulations. Alternatively, the oil may be an oil suitable for forming liposomes. According to one embodiment, the oil is a straight chain hydrocarbon oil having 10 to 150 carbon atoms, more preferably the oil is a saturated n-alkane or isoalkane hydrocarbon having 10 to 26 carbon atoms. Unsaturated alkene hydrocarbons can be used, but are less chemically stable.

[0049] According to one embodiment, the oil provided herein is a mineral oil. According to one embodiment, the oil provided herein is a light mineral oil. According to one embodiment, the oil provided herein is a heavy mineral oil.

[0050] According to one embodiment, the oil comprises a mixture of light and heavy mineral oils, each having a different viscosity. According to a particular embodiment, the light mineral oil has a viscosity of about 3.0 mm at 40° C. 2 s ‐1 from about 34.4 mm 2 s ‐1 According to a particular embodiment, the heavy mineral oil has a kinematic viscosity of about 34.5 mm at 40° C. 2 s‐1 From about 150 mm 2 s ‐1 According to yet another embodiment, the light mineral oil has a kinematic viscosity of about 28 mm at 40° C. 2 s ‐1 From about 30 mm 2 s ‐1 According to yet another embodiment, the heavy mineral oil has a kinematic viscosity of about 65 mm at 40° C. 2 s ‐1 From about 71 mm 2 s ‐1 The kinematic viscosity of

[0051] The amount of oil in the oil-in-water emulsion may vary within reasonable limits, but the application to the eye should not exceed 25 μL. According to one embodiment, the amount does not exceed 15 μL. According to one embodiment, the amount varies between about 1 μL and 10 μL. According to one embodiment, the amount varies between about 1 μL and 30 μL.

[0052] The total amount of oil or oil combination may be present in the ophthalmic suspension in an amount of at least about 0.1% by weight based on the total weight of the ophthalmic suspension. According to one embodiment, the oil or oil combination is present in an amount of at least about 0.5% by weight. According to one embodiment, the oil or oil combination is present in an amount of at least about 1.0% by weight. According to one embodiment, the oil or oil combination is present in an amount of at least about 1.5% by weight. According to one embodiment, the oil or oil combination is present in an amount of less than about 12.5% ​​by weight. According to one embodiment, the oil or oil combination is present in an amount of less than about 10.0% by weight. According to one embodiment, the oil or oil combination is present in an amount of less than about 7.5% by weight. According to one embodiment, the oil or oil combination is present in an amount of less than about 6.6% by weight. According to one embodiment, the oil or oil combination is present in an amount of less than about 6.5% by weight. According to one embodiment, the oil or oil combination is present in an amount between about 0.5% by weight and about 12.5% ​​by weight. According to one embodiment, the oil or oil combination is present in an amount between about 1.0% and about 8.5% by weight. According to one embodiment, the oil or oil combination is present in an amount between about 3.5% and about 7.5% by weight. According to one embodiment, the oil or oil combination is present in an amount between about 4.0% and about 7.0% by weight. According to one embodiment, the oil or oil combination is present in an amount between about 4.4% and about 6.6% by weight. According to one embodiment, the oil or oil combination is present in an amount between about 4.95% and about 6.05% by weight.

[0053] According to one embodiment, the oil comprises a mixture of two or more oils of different weights. According to such an embodiment, the oil is a mixture of at least one light oil and at least one heavy oil. According to a particular embodiment, the oil is a mixture of mineral oils commercially available under the trademarks Drakeol® 15 (light mineral oil) and Drakeol® 35 (white heavy mineral oil). According to one embodiment, the light mineral oil can be present in an amount of about 0.5% to about 1.5% by weight. According to one embodiment, the light mineral oil can be present in an amount of about 0.6% to about 1.4% by weight. According to one embodiment, the light mineral oil can be present in an amount of about 0.7% to about 1.3% by weight. According to one embodiment, the light mineral oil can be present in an amount of about 0.8% to about 1.2% by weight.

[0054] According to one embodiment, the heavy mineral oil can be present in an amount of about 2.7% to about 6.5% by weight. According to one embodiment, the heavy mineral oil can be present in an amount of about 2.9% to about 6.3% by weight. According to one embodiment, the heavy mineral oil can be present in an amount of about 3.1% to about 6.1% by weight. According to one embodiment, the heavy mineral oil can be present in an amount of about 3.3% to about 5.9% by weight. According to one embodiment, the heavy mineral oil can be present in an amount of about 3.5% to about 5.7% by weight. According to one embodiment, the heavy mineral oil can be present in an amount of about 3.7% to about 5.5% by weight. According to one embodiment, the heavy mineral oil can be present in an amount of about 4.05% to about 4.95% by weight.

[0055] According to one embodiment, the light mineral oil may be present in an amount of about 1.0% by weight and the heavy mineral oil may be present in an amount of about 4.5% by weight.

[0056] The eye drop suspension provided herein comprises a wax ester dispersion. The wax dispersion comprises at least one wax ester. The role of the wax esters and their hydrolysis products is believed, without being bound to a particular theory, to maintain the integrity of the stromal layer itself, to bind the mucin layer to the aqueous layer, and to bind the aqueous layer to the lipid layer. In addition, the wax esters help thicken the mucin, aqueous, and lipid layers themselves. The binding process and subsequent homeostasis enabled by the wax esters allows the layers of the tear film to stick together, thereby allowing the entire tear film to remain on the eye for an extended period of time. The eye drop suspension provided herein penetrates all layers of the tear film, including the five stromal layers, where no product has been incorporated to date.

[0057] According to one embodiment, the at least one wax ester is present in an amount of at least about 0.2% by weight. According to one embodiment, the at least one wax ester is present in an amount of at least about 0.3% by weight. According to one embodiment, the at least one wax ester is present in an amount of at least about 0.4% by weight. According to one embodiment, the at least one wax ester is present in an amount of at least about 0.5% by weight. According to one embodiment, the at least one wax ester is present in an amount of at least about 0.6% by weight. According to one embodiment, the at least one wax ester is present in an amount of at least about 0.7% by weight. According to one embodiment, the at least one wax ester is present in an amount of at least about 0.8% by weight. According to one embodiment, the at least one wax ester is present in an amount of at least about 0.9% by weight. According to one embodiment, the at least one wax ester is present in an amount of at least about 1.0% by weight. According to one embodiment, the at least one wax ester is present in an amount of about 1.8% by weight or less. According to one embodiment, the at least one wax ester is present in an amount of about 0.2% to about 1.8% by weight. According to one embodiment, the at least one wax ester is present in an amount of about 0.4% to about 1.6% by weight. According to one embodiment, the at least one wax ester is present in an amount of about 0.6% to about 1.4% by weight. According to one embodiment, the at least one wax ester is present in an amount of about 0.8% to about 1.2% by weight. According to one embodiment, the at least one wax ester is present in an amount of about 1.0% by weight.

[0058] According to one embodiment, the at least one wax ester is beeswax. According to one embodiment, the beeswax is natural beeswax. The beeswax may be Cera Alba, Cera Flava, or a combination thereof. The beeswax may be USDA certified organic beeswax or conventional natural beeswax. According to one embodiment, the at least one wax ester is synthetic beeswax.

[0059] According to one embodiment, wax ester particles can be emulsified in eye drop suspension to form a specific particle size range.The irregular shape and charge of the particle itself allows wax ester particles to have more surface area to interact with oil as provided herein, allowing wax ester particles to degrade at different rates, with smaller wax ester particles and oil particles degrading quickly and larger wax ester particles degrading more slowly.As wax ester particles degrade, it is believed that the oil and wax ester particles interact with the natural tear film to support a more stable barrier for the aqueous tear film that is prone to evaporation.

[0060] The ophthalmic suspensions provided herein comprise wax ester particles that exhibit a particle size that allows the wax ester particles to be retained in the eye. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 2.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 3.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 4.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 5.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of no greater than about 30.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of no greater than about 25.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of no greater than about 24.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of no greater than about 23.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of no greater than about 22.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of no greater than about 21.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of no greater than about 20.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 2.0 microns, but not greater than about 25.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 2.0 microns, but not greater than about 20.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 2.0 microns, but not greater than about 15.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 3.0 microns, but not greater than about 24.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 4.0 microns, but not greater than about 23.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 5.0 microns, but not greater than about 22.0 microns. According to one embodiment, the wax ester particles exhibit an average particle size of at least about 6.0 microns, but not greater than about 21.0 microns.According to one embodiment, the wax ester particles exhibit an average particle size of at least about 7.0 microns, but not greater than about 20.0 microns.

[0061] The wax ester dispersion (dispersion) comprises at least one surfactant. According to one embodiment, the wax dispersion comprises two or more surfactants. According to one embodiment, the wax dispersion comprises a combination of surfactants for the dual purpose of stabilizing the suspension and spreading and maintaining the suspension on the ocular surface after application to the eye. The combination of surfactants can comprise a primary surfactant and a secondary surfactant. The at least one surfactant allows the formation of a suspension that is stable during manufacture and storage, but is desirably meta stable when applied to the ocular surface. The at least one surfactant provided herein is suitable for rapid differentiation when applied to the eye, which allows a non-blurring film of oil to rapidly form on the ocular surface, spreading the wax ester through each phase of the emulsified suspension.

[0062] According to one embodiment, the at least one surfactant comprises at least one polyoxyethylene sorbitan monooleate, such as polyoxyethylene-sorbitan-20 mono-oleate, commercially available as polysorbate 80 or Tween 80. According to one embodiment, the polyoxyethylene sorbitan monooleate may be present in the ophthalmic suspension in an amount of about 0.1% to about 0.7% by weight. According to one embodiment, the polyoxyethylene sorbitan monooleate may be present in the ophthalmic suspension in an amount of about 0.2% to about 0.6% by weight. According to one embodiment, the polyoxyethylene sorbitan monooleate may be present in the ophthalmic suspension in an amount of about 0.3% to about 0.6% by weight. According to one embodiment, the polyoxyethylene sorbitan monooleate may be present in the ophthalmic suspension in an amount of about 0.4% to about 0.6% by weight.

[0063] According to one embodiment, the at least one surfactant comprises diphosphatidylglycerol, such as dimyristoylphosphatidylglycerol or commercially available 1,2-dimyristoyl-sn-glycero-3-phosphorylglycerol sodium salt (DMPG). The surfactant can be lysophosphatidylcholine, phosphatidic acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, or phosphatidylserine. In other embodiments, the surfactant comprises at least one anionic surfactant. According to one embodiment, the anionic surfactant can be one or more of anionic polar phospholipids, such as lysophosphatidylcholine, phosphatidic acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, or phosphatidylserine. According to another embodiment, the anionic polar phospholipid may be one or more of phosphatidic acid (PA), phosphatidylserine (PS), phosphatidylinositol (PI), and its phosphorylated derivatives may be phosphoinositides (e.g., phosphatidylinositol-4-phosphate [PI4P] and phosphatidylinositol-4,5-bisphosphate, and dimyristoyl phosphatidylglycerol). According to one embodiment, the anionic surfactant is dimyristoyl phosphatidylglycerol. According to one embodiment, the surfactant is a mixture of two surfactants provided herein. According to one embodiment, the surfactant is a combination of two anionic polar phospholipids. According to one embodiment, the anionic polar surfactant is a mixture of Tween 80 and anionic polar dimyristoyl phosphatidylglycerol.

[0064] According to one embodiment, dimyristoyl phosphatidylglycerol may be present in the ophthalmic suspension in an amount of about 0.1% to about 0.7% by weight. According to one embodiment, dimyristoyl phosphatidylglycerol may be present in the ophthalmic suspension in an amount of about 0.2% to about 0.6% by weight. According to one embodiment, dimyristoyl phosphatidylglycerol may be present in the ophthalmic suspension in an amount of about 0.3% to about 0.6% by weight. According to one embodiment, dimyristoyl phosphatidylglycerol may be present in the ophthalmic suspension in an amount of about 0.4% to about 0.6% by weight.

[0065] According to one embodiment, the ophthalmic suspensions provided herein include one or more phosphate salts. According to one embodiment, the ophthalmic suspensions include both monobasic and dibasic phosphate salts.

[0066] According to certain embodiments, the monobasic phosphate is a monosodium phosphate, such as NaH2PO4. According to one embodiment, the monobasic phosphate may be present in an amount of about 0.01% to about 0.05% by weight. According to one embodiment, the monobasic phosphate may be present in an amount of about 0.02% to about 0.04% by weight. According to one embodiment, the monobasic phosphate may be present in an amount of about 0.03% by weight.

[0067] According to certain embodiments, the dibasic phosphate is a disodium phosphate such as NaHPO (sodium hydrogen phosphate or sodium phosphate dibasic). According to one embodiment, the dibasic phosphate may be present in an amount of about 0.1% to about 0.5% by weight. According to one embodiment, the dibasic phosphate may be present in an amount of about 0.2% to about 0.3% by weight. According to one embodiment, the dibasic phosphate may be present in an amount of about 0.25% by weight.

[0068] According to one embodiment, the ophthalmic suspension provided herein comprises at least one salt. According to one embodiment, the at least one salt is sodium chloride or other salt suitable for application to the eye. The at least one salt can be present in an amount of about 0.50% to about 0.75% by weight. According to another embodiment, the at least one salt can be present in an amount of about 0.55% to about 0.70% by weight. According to another embodiment, the at least one salt can be present in an amount of about 0.55% by weight. According to another embodiment, the at least one salt can be present in an amount of about 0.67% by weight.

[0069] According to one embodiment, the ophthalmic suspension provided herein comprises at least one glycosylaminoglycan. Suitable glycosylaminoglycans include hyaluronic acid (HA), the corresponding sodium salt, sodium hyaluronate, or a combination thereof. According to one embodiment, the hyaluronic acid or sodium hyaluronate may be present in the ophthalmic suspension in an amount of about 0.06% to about 0.5% by weight. According to one embodiment, the hyaluronic acid or sodium hyaluronate may be present in the ophthalmic suspension in an amount of about 0.07% to about 0.4% by weight. According to one embodiment, the hyaluronic acid or sodium hyaluronate may be present in the ophthalmic suspension in an amount of about 0.08% to about 0.3% by weight. According to one embodiment, the hyaluronic acid or sodium hyaluronate may be present in the ophthalmic suspension in an amount of about 0.09% to about 0.2% by weight. According to one embodiment, hyaluronic acid or sodium hyaluronate may be present in the ophthalmic suspension in an amount of about 0.1% by weight.

[0070] According to one embodiment, the ophthalmic suspension provided herein optionally comprises ethylenediaminetetraacetic acid (EDTA). According to one embodiment, the EDTA may be present in the ophthalmic suspension in an amount of about 0.007% to about 0.02% by weight. According to one embodiment, the EDTA may be present in the ophthalmic suspension in an amount of about 0.008% to about 0.015% by weight. According to one embodiment, the EDTA may be present in the ophthalmic suspension in an amount of about 0.01% by weight.

[0071] According to one embodiment, the ophthalmic suspension provided herein optionally comprises at least one anti-inflammatory compound, such as inactivated brewer's yeast or adenosine diphosphate ribose.Currently, the at least one anti-inflammatory compound does not affect the stability or ocular performance of the ophthalmic suspension.According to one embodiment, the anti-inflammatory compound may be present in the ophthalmic suspension in an amount of about 0.02% by weight to about 1.0% by weight.

[0072] Other additives may be present in the eye drop suspension. Such additives include small amounts of neutral lipids and oils, such as one or more triglycerides, partially hydroxylated esters, cholesterol esters, high molecular weight isoprenoids; stabilizers; additional surfactants; mucomimetics (e.g., HP Guar); preservatives; pH adjusters; salts; buffers, glycerin, sugars in sufficient concentrations to form a hypotonic composition such that the emulsion is not stable in the ocular environment; emollients; demulcents; polymers of ethylene oxide, propylene oxide, or butylene oxide; carboxymethylcellulose (CMC); hydroxypropylmethylcellulose (HPMC); polyacrylic acid (PAA); polyethylene glycol (PEG); propylene glycol (PG); or polyvinyl alcohol (PVA).

[0073] The ophthalmic suspensions provided herein may have an osmolality that may be adjusted by the concentration of a salt such as NaCl. According to one embodiment, the ophthalmic suspensions provided herein have an osmolality of at least about 245 mOsmol / kg. According to one embodiment, the ophthalmic suspensions provided herein have an osmolality of at least about 260 mOsmol / kg. According to one embodiment, the ophthalmic suspensions provided herein have an osmolality of about 245 mOsmol / kg to about 315 mOsmol / kg. According to one embodiment, the ophthalmic suspensions provided herein have an osmolality of about 245 mOsmol / kg to about 310 mOsmol / kg. According to one embodiment, the ophthalmic suspensions provided herein have an osmolality of about 255 mOsmol / kg to about 305 mOsmol / kg. According to one embodiment, the ophthalmic suspension provided herein has an osmolality of about 270 mOsmol / kg to about 300 mOsmol / kg. According to one embodiment, the ophthalmic suspension provided herein has an osmolality of about 275 mOsmol / kg to about 295 mOsmol / kg. According to one embodiment, the ophthalmic suspension provided herein has an osmolality of about 280 mOsmol / kg to about 290 mOsmol / kg. According to one embodiment, the ophthalmic suspension provided herein has an osmolality of about 282 mOsmol / kg to about 289 mOsmol / kg. According to one embodiment, the ophthalmic suspension provided herein has an osmolality of about 285 mOsmol / kg to about 287 mOsmol / kg. According to one embodiment, the ophthalmic suspension provided herein has an osmolality of about 286 mOsmol / kg.

[0074] According to one embodiment, the ophthalmic suspension provided herein has a pH of about 6.8-7.8. According to one embodiment, the ophthalmic suspension provided herein exhibits a pH of about 6.9-7.7. According to one embodiment, the ophthalmic suspension provided herein exhibits a pH of about 7.0-7.6. According to one embodiment, the ophthalmic suspension provided herein exhibits a pH of about 7.0-7.4. According to one embodiment, the ophthalmic suspension provided herein exhibits a pH between about 7.1-7.5. According to one embodiment, the ophthalmic suspension provided herein exhibits a pH of about 7.2-7.4. According to one embodiment, the ophthalmic suspension provided herein exhibits a pH of about 7.2. According to one embodiment, the ophthalmic suspension provided herein exhibits a pH of about 7.3. The pH can be adjusted by adding a pH adjuster such as HCl or citric acid or a base such as NaOH.

[0075] The viscosity of the ophthalmic suspensions described herein may vary, but the viscosity allows for suitable droplet size for application to the eye. According to one embodiment, the viscosity of the ophthalmic suspensions provided herein is between about 5 centipoise at 25° C. and about 8 centipoise at 25° C. The viscosity of the ophthalmic suspensions described herein can be measured using techniques well known to those skilled in the art. Non-limiting examples of methods for measuring viscosity include a falling ball viscometer, a viscosity cup, a consistometer (measuring flow up a slope), a capillary glass viscometer, or a rotational viscometer. Various instruments are commercially available (Cole-Palmer Instrument Co., Vernon Hills, IL, USA).

[0076] The eye drop suspension provided herein can be preservative-free. In some embodiments, the preservative-free eye drop suspension is delivered in a single-use package due to the risk of bacterial contamination associated with conventional multi-use applications. In another embodiment, the eye drop suspension is delivered in a sterile multi-dose bottle. Examples include Aptar Pharma (Crystal Lake, IL, USA) multi-dose squeeze dispenser that is mechanically actuated and utilizes a filter membrane (see PCT Publications WO 2017 / 074420 and WO 2017 / 132190 (Aptargroup, Inc.) and Nemera La Verpillier (France) multi-dose squeeze bottle (see PCT Publication WO2013 / 140069)), each of which is incorporated by reference with respect to such containers.

[0077] According to another embodiment, the ophthalmic suspensions provided herein may include at least one preservative. According to another embodiment, the ophthalmic suspensions provided herein may include at least one borate buffer.

[0078] A method for preparing an ophthalmic suspension vehicle is provided. According to one embodiment, the method for preparing an ophthalmic suspension vehicle includes separately preparing a mixture of oils (e.g., heavy mineral oil and light mineral oil), adding a wax ester component such as beeswax, and heating the mixture to a temperature above the melting point of the wax ester (e.g., about 63°C to about 71°C). In a separate water / water phase, salts, phosphates, surfactants, and any other water-soluble components can be prepared and heated to about 85°C. The oil phase can then be slowly added to the water / water phase, mixed, and homogenized to form the ophthalmic suspension vehicle. The resulting ophthalmic suspension vehicle is autoclaved. Throughout the process, the ophthalmic suspension vehicle continues to be mixed.

[0079] According to one embodiment, a method of preparing an ophthalmic suspension vehicle includes separately preparing an oil phase (e.g., heavy mineral oil and light mineral oil) by heating to a temperature of about 63° C. to about 71° C. The step of preparing the oil phase can optionally include adding or introducing at least one wax acid ester to the oil phase, followed by heating the mixture to a temperature above the melting point of the wax acid ester (e.g., about 63° C. to about 71° C.).

[0080] According to one embodiment, the method for preparing an ophthalmic suspension vehicle includes separately preparing an aqueous phase, which can be prepared by mixing at least one wax ester, at least one salt, at least one phosphate, at least one surfactant, and any other water-soluble components, and then heating the mixture to a temperature above the melting point of the wax ester (e.g., about 63°C to about 71°C).

[0081] According to one embodiment, the oil phase as provided herein can then be slowly added to the aqueous phase, mixed and homogenized to form an ophthalmic suspension vehicle.The resulting ophthalmic suspension vehicle can then be autoclaved.According to such an embodiment, therefore, the individual oil and aqueous phases are not autoclaved separately before being combined.According to one embodiment, the resulting ophthalmic suspension vehicle is not autoclaved and sterilized, for example, by e-beam or gamma irradiation, or by alternative methods such as filtration.

[0082] According to an alternative embodiment, a method for preparing an ophthalmic suspension vehicle is provided. The alternative method includes preparing a wax dispersion by mixing or dissolving at least one wax ester (e.g., natural beeswax) with a surfactant and purified or deionized water. According to one embodiment, at least one wax ester can be mixed or dissolved such that the natural wax ester can be delivered in a controlled manner and results in increased residence time on the eye. According to one embodiment, the step of preparing the wax dispersion includes dissolving one or more salts and one or more phosphates, such as monosodium phosphate and disodium phosphate, in purified or deionized water. According to one embodiment, the step of preparing the wax dispersion includes heating one or more salts, phosphates, surfactants and wax esters and stirring the resulting dispersion. According to one embodiment, the dispersion is heated to about 70°C to about 90°C. According to certain embodiments, wax particle dispersions can be prepared by homogenizing molten beeswax (~1.0%) in purified or distilled water containing phosphate salts plus Octoxynol-40 (~0.2%, 1,2-dimyristoyl-sn-glycero-3-phosphorylglycerol sodium salt (DMPG)) at about 75° C. The high cloud point of Octoxynol-40 (>100° C) allows for emulsification efficiency at higher temperatures due to its reduced water solubility (effectively lowering the HLB value).

[0083] An alternative method includes preparing an oil-in-water emulsion. According to one embodiment, the oil-in-water emulsion is prepared by mixing mineral oils of different weights or viscosities as described herein, and heating the mixture of mineral oils to a temperature of about 65° C. to about 75° C. According to one embodiment, the method includes introducing the heated mixture of mineral oils dropwise into purified water or ion-exchanged water, and homogenizing the water and mineral oil mixture to form an oil-in-water emulsion. The pH of the oil-in-water emulsion can be adjusted to a range of about 6.8 to about 7.8.

[0084] An alternative method involves autoclaving the wax dispersion and the oil-in-water emulsion separately, with the integrity of the emulsion being maintained during autoclaving.

[0085] Without being bound to a particular theory, it is believed that the mechanism responsible for irreversible aggregation of wax (wax breakout) under autoclave conditions involves the presence of a relatively high (near isotonic) salt concentration. This high ionic load is believed to significantly reduce the zeta potential of the wax ester particles, which removes an important stabilization mechanism when these dispersions are subjected to autoclave conditions.

[0086] Another method involves aseptically blending an autoclaved beeswax dispersion and an oil-in-water emulsion to prepare an ophthalmic suspension vehicle as provided herein. According to one embodiment, the wax ester particles may be stabilized by a surfactant in the oil phase that prevents agglomeration and droplet coalescence during cooling.

[0087] To maintain a storage stable suspension, separate preparation and autoclaving of the wax ester particle dispersion and emulsion components are performed, followed by a sterile blending step to ensure sterility of the product. The sterile blending step of the autoclaved beeswax dispersion and oil-in-water emulsion ensures that the desired final concentrations of mineral oil, beeswax, and other ingredients are present in the ophthalmic suspension. According to one embodiment, the oil-in-water emulsion is formulated with increased ingredient levels, while the beeswax particles are emulsified in water with added surfactant. The concentrations of the various ingredients in the two fractions (before autoclaving) can be adjusted to allow for a relatively wide variation in the final emulsified suspension composition.

[0088] According to one embodiment, the preparation method includes the steps of separately preparing a mixture of oils (e.g., heavy mineral oil and light mineral oil), adding a wax ester component such as beeswax, and heating the mixture to a temperature above the melting point of the wax esters (e.g., 63°C to 71°C). In a separate phase, salts, phosphates, surfactants, and any other water-soluble ingredients are prepared and heated to about 85°C. The oil phase is slowly added to the water phase, mixed, and homogenized. The resulting preparation is autoclaved. The preparation continues to be mixed throughout the process.

[0089] According to one embodiment, the preparation method includes mixing an oil phase containing light minerals, mineral oils and wax esters (e.g., natural or synthetic beeswax) with an aqueous phase containing salts, phosphates, surfactants and water-soluble glycosaminoglycans, followed by homogenization and autoclaving to form a complex combination of particles. Large particles of about 2 microns to about 15 microns are observed in the resulting preparation, and particle analysis is performed by Microtrack particle size analysis. According to one embodiment, measurement of the particles for zeta potential or surface charge shows a zeta potential of greater than -60 mV. According to one embodiment, measurement of the particles for zeta potential or surface charge shows a zeta potential of about -60 mV to about -110 mV. In the preparation, there are both charged particles resulting from interactions with surfactants that can be found in the aqueous phase and particles found in the oil phase that are submicron in size. The particles in the oil phase can be wax-ester particles or oil wax-ester mixtures with neutral or surface charges.

[0090] In the absence of added surfactants, large particle dispersions cannot be prepared. The operative particle formation mechanism differs from the simple nucleation and particle growth model used to form submicron-sized dispersions. The added surfactant stabilizes the beeswax droplets growing during homogenization. The surfactant prevents droplet aggregation during the cooling period after autoclaving. The chemistry of the system results in particle dispersions that are stable in the autoclave (as molten wax droplets) but that irreversibly aggregate when the decrease in sample temperature during sample cooling approaches the melting point (crystallization temperature) of beeswax. Specifically, the presence of a surfactant such as DMPG is also believed to aid in stabilizing beeswax emulsions at the elevated temperatures present during autoclaving. In particular, the surfactant is believed to stabilize the molten wax droplets by redistributing them from a dissolved state in the aqueous phase onto the particle / droplet surfaces and preventing aggregation. As the temperature is continuously increased during autoclaving, the surfactant becomes increasingly insoluble in water and tends to migrate toward the particle surface (droplet / aqueous interface), helping to stabilize the molten wax droplets.

[0091] Although zeta potential values ​​cannot be measured under autoclave conditions, sealed beeswax particle / droplet dispersions remain stable at 121° C. (with gentle agitation) when dispersed in water. Furthermore, the oil-in-water emulsions provided herein are not subject to significant amounts of particle aggregation when prepared according to the present method. It is believed that the strong long-term stability is a result of such a method.

[0092] Working Example Preparation of eye drop suspension The ophthalmic suspensions used in the examples provided herein are set forth in Table 1 below. [Table 1]

[0093] To prepare a 500 gram batch of eye drop suspension, a batch of NaCl, dimyristoyl phosphatidylglycerol (DPMG), NaH2PO4 and Na2HPO4 were dissolved in purified water in a beaker. Tween 80, DPMG, sodium hyaluronate were added to the aqueous solution and heated to 85°C (+ / -2°C) with continuous stirring. In a separate glass beaker, Drakeol® 15, Drakeol® 35 and wax esters were mixed and heated to 71°C (+ / -2°C) with continuous stirring for 10 minutes (+ / -20 seconds). The aqueous phase was homogenized for 30 seconds (+ / -5 seconds). With the homogenizer running, the oil phase was preheated to 71°C (+ / -2°C) and added dropwise to the aqueous phase at 85°C (+ / -2°C). After oil addition was complete, the homogenizer was run. The target homogenization speed was approximately 10,000 RPM (+ / - 400 RPM) and the target homogenization time was approximately 4 minutes (+ / - 20 seconds). The homogenization procedure was terminated and stirring continued until the suspension reached room temperature (approximately 4 hours). While stirring, pH and osmolality were checked and adjusted (target pH: 7.2-7.4: osmolality 240 mOsmol / kg-290 mOsmol / kg). While stirring, the suspension mixture was dispensed using a syringe into an autoclavable bottle and loaded with a magnetic stir bar. The bottle and autoclave were closed for 35 minutes (+ / - 1 minute) and heated to 15 psi and 121 °C with stirring. The suspension was allowed to cool to room temperature while stirring (approximately 6 hours).

[0094] Example 1 The effect of wax esters on ocular emulsion retention. A study was conducted to determine the effect of wax esters on lipid layer thickness. With one drop, blur and comfort scores were recorded and interferometric measurements of lipid layer thickness were taken in both eyes at 5, 30, 60, and 120 minute intervals. The improvement in lipid layer thickness from baseline was calculated by subtracting (or adding) the net result of the control drop at each time interval. The results for the eye drop suspensions in Table 1 are shown in Table 2. An eye drop solution without wax esters (commercially available as Soothe® XP) and two additional commercially available solutions (Refresh Optive® Advanced and Systane® Balance) were tested in the studies shown in Tables 2, 3, 4, and 5 below, respectively.

[0095] [Table 2]

[0096] [Table 3]

[0097] [Table 4]

[0098] [Table 5]

[0099] Testing revealed that mineral oil alone was rapidly lost when added to the ocular environment, likely through periodic replacement of the tear film or ocular drainage from the lacrimal gland. The addition of wax esters was shown to provide an eye drop suspension that is retained in the ocular environment for a longer period, allowing the eye drop suspension to continue to enhance lipid layer growth.

[0100] Example 2 Wax and surfactant selection The inclusion of different wax acid esters provides an indication of important properties necessary to maintain the efficacy of the wax acid ester addition to the ocular environment. The role of the wax ester component and the use of surfactant components were evaluated to understand their role in providing lipid layer enhancement. The following wax esters were evaluated: wax ester, Kester K-24, Branched Kester BK-40, and synthetic wax esters.

[0101] One or more of the following surfactants were used in conjunction with the wax esters: DMPG dimyristoyl phosphatidylglycerol (anionic phospholipid); IGEPAL CA 897 ethoxylated (40)-1,1,3,3 tetramethylbutylphenol; Phospholipon 90G phosphatidylcholine (zwitterionic charged phospholipid); and IGEPAL CO-890 polyoxyethylene (40) nonylphenyl ether, branched. The results are summarized in Tables 6-10 below.

[0102] [Table 6]

[0103] [Table 7]

[0104] [Table 8]

[0105] [Table 9]

[0106] [Table 10]

[0107] The above results show that the low melting wax esters had no significant ocular effect compared to the control product and were similar to the commercial product. Natural beeswax esters and synthetic beeswax esters showed the best overall results with improved results for all surfactants in combination with natural beeswax esters.

[0108] Example 3 Selection of wax and surfactant combinations Natural and synthetic beeswax esters were tested to determine which surfactants could provide early lipid layer improvement and extended residence time on the eye (in addition to in-bottle (storage) stability). One or more of the following surfactants were used with the wax esters: DMPG dimyristoyl phosphatidylglycerol (anionic phospholipid); IGAPEL CA 897 ethoxylated (40)-1,1,3,3 tetramethylbutylphenol; Phospholipon 90G phosphatidylcholine (zwitterionic charged phospholipid); and IGEPAL CO-890 polyoxyethylene (40) nonylphenyl ether, branched. The results for natural beeswax are summarized in Table 11 below. The results for synthetic beeswax are summarized in Table 12 below.

[0109] [Table 11]

[0110] [Table 12]

[0111] Natural beeswax esters and the anionic surfactant DMPG were shown to provide superior results over all time intervals, with natural beeswax generally shown to achieve and maintain a higher average increase in lipid layer thickness after 120 minutes.

[0112] Example 4 particle size To obtain the desired properties, the oil and wax ester portions of the ophthalmic suspension should be retained in the ocular environment for an extended period of time. The particle size of the wax ester is preferably maintained to increase the long-lasting lipid layer on the eye over an extended period of time.

[0113] Particle size was determined using a Microtrac Sync 3R Flow instrument. Particle size analysis was performed using approximately 6.0 mL of sample, which could be stored in a plastic bottle until testing. Each bottle was shaken 10 times prior to testing. The entire cap was then removed and approximately 2 drops of sample were transferred to the Microtrac Sync 3R flow device using a plastic pipette. The sample was loaded into the particle size analyzer. Approximately 2 drops (0.060 g) of sample were injected into a 200 mL deionized water circulating chamber and the test was started.

[0114] Results for mineral oil alone showed that loss of added mineral oil did not exceed 30 minutes, as was observed with the competitive Systane® Balance. Results are summarized in Table 13.

[0115] The processing parameters labeled "Homogenizer" in Table 13 refer to processing with the homogenizer alone, ranging from about 10k to about 18k rpm, for about 4 to about 8 minutes. The other processing parameters refer to the pressure of the microfluidizer system used to assess homogenity. This additional processing was added after the initial homogenization and resulted in a reduction in particle size, but at the expense of reduced clinical performance (average increase above baseline). More specifically, based on particle size analysis performed on several test formulas, the homogenizer-only process resulted in an average particle size in the range of 2 to 20 microns, while samples further processed with the microfluidizer resulted in an average particle size of ≦1 micron. Actual measurements of the formulations determined a significant range of particle size and distribution. Specifically, formulations with an average particle size of about 1 micron did not remain in the eye, while the best performing formulations had an average particle size in the range of 5 to 20 microns under the conditions measured.

[0116] [Table 13]

[0117] Example 5 Performance of eye drop suspensions A study was conducted to examine the ocular performance of the eye drop suspensions in Table 1. The study yielded favorable results in terms of both emulsion suspension properties and ocular performance. Specifically, the study was conducted in patients with low levels of lipid layer thickness (LLT) and reduced tear film, based on day-ahead and day-1 screening. Interferometry was used to measure the lipid layer thickness of the tear film at baseline. The baseline lipid layer thickness of these patients ranged from 25 nm to 70 nm, with a mean of 45 nm. A lipid layer thickness of less than 70 nm was considered deficient.

[0118] After baseline measurements were taken, subjects self-instilled one drop of the eye drop suspension in Table 1 (Example 1) and one drop of a control solution into the contralateral eye. The control solution chosen was commercially available as Systane® Ultra PF (a commercially available, preservative-free, non-greasy liquid drop).

[0119] The primary objective was the evaluation of increased lipid layer thickness, and the first challenge was to develop strict inclusion and exclusion criteria for patient recruitment in order to select subjects with chronically dry tear film due to evaporative dry eye (e.g., meibomian gland dysfunction or MGD) rather than partial blinking or a side effect of another drug or procedure. The study primarily sought subjects with baseline lipid layer thickness <55 nm in at least one eye and partial blink rate <50%, both measured using LipiView (Johnson and Johnson). Furthermore, patients with high risk factors such as other ocular diseases, pregnancy, or recent use of certain medications were not considered for this evaluation.

[0120] Once the inclusion criteria were established, a formal protocol had to be created for clinicians and personnel to follow. In this document, each step of the patient assessment process was laid out in a checkbox format, from the initial patient assessment and on-the-day participation confirmation to the actual assessment and measurement process. Each step was documented for physicians and staff to follow sequentially: 1.Selection 2. Check for exclusions 3. Eye health check (evaluation will be at the discretion of the doctor) 4. Baseline LLT measurements 5. SPEED Pre-assessment (standardized patient assessment of dry eye), see Korb et al. Lid wiper epitheliopathy and dry eye symptoms. Eye Contact Lens. 2005 Jan;31(1):2-8; and Korb et al. The effect of two novel lubricant eye drops on tear film lipid layer thickness in subjects with dry eye symptoms. Optom Vis Sci. 2005 Jul;82(7):594-601, which are incorporated by reference for the research studies. 6. Instillation of test and control drugs Measurements at intervals of 7.5, 30, 60, 120, 180, and 240 minutes 8. SPEED Ex-post Evaluation

[0121] The eye drops were masked to patients but not to physicians or personnel. All study results were recorded on data records masked to patient identity.

[0122] Twelve patients completed the study over a two-week period. The results, as shown in Tables 14 and 15, show the raw mean lipid layer thickness readings of the 12 patients measured. The ophthalmic suspension vehicles of Table 1 showed a significant increase in lipid layer thickness at the 5 and 30 minute time points. Significant differences were noted between the ophthalmic suspension vehicles and the control drops at all measurement time points. The ophthalmic suspension vehicles maintained a mean lipid layer thickness of 72.5 (+ / -3.8) nm at the 4 hour mark compared to the control which was 61.8 (+ / -2.2) nm.

[0123] [Table 14]

[0124] [Table 15]

[0125] Based on the raw data of paired eyes, the mean baseline lipid layer thickness of test eye and control eye shows a difference.Thus, in addition to using lipid layer thickness at each time point as the key measure, the mean increase in lipid layer thickness from baseline in patients who applied both test and control drops is evaluated.Table 16 shows the increase in lipid layer thickness obtained from the eye drop suspension vehicles listed in Table 1.Table 17 shows the increase in lipid layer thickness obtained from Systane® Ultra PF solution.

[0126] A clear separation of the test and control solutions at each time point is illustrated, with the lipid layer thickness of the ophthalmic suspension increasing by nearly 50% at the 4 hour mark. Thus, the decrease in lipid layer thickness is delayed well beyond the 4 hour mark before returning to baseline. If the dissolution rate remained linear, it is likely that a significant lipid layer thickness increase would continue well beyond 8 hours using only a single drop of ophthalmic suspension.

[0127] [Table 16]

[0128] [Table 17]

[0129] Two subjective questions were asked of patients immediately upon instillation in each eye. The first question asked patients to rate their initial comfort on a scale of 0 to 100. The second question asked patients to report the duration of any visual blurring they noticed. With the ophthalmic suspension, the average patient had a comfort score of 85 out of 100 and slight visual blurring of 5.6 seconds. For the control drops, the average results were 92 out of 100 and 2.9 seconds. There was a difference between the test and control in both of these metrics, but the blurring lasted less than 3 seconds with the ophthalmic suspension, while the initial comfort score was 7 out of 100.

[0130] With the ophthalmic suspension, most patients reported no blurring, but the longest duration of blurring was 30 seconds (1 test eye, 1 control eye). Patient comfort scores were similar, ranging from 45 to 100 in the test eye and 50 to 100 in the control eye. Based on thousands of hours of in-house testing, comfort and blurring are similar to the control solution.

[0131] The self-administered SPEED Dry Eye Symptom Questionnaire was incorporated into the study. A score of 8 or greater indicated the presence of dry eye. Patient response was a mean SPEED score of 13.58 at the start of the study before instillation. All patients examined reported an initial SPEED score of greater than 8.

[0132] Four hours after instillation, patients were re-examined using the SPEED. The mean result of the post-assessment was a score of 10.5, with no patients reporting an increase in score and five patients reporting a score below 8. The assessment did not differentiate between symptoms in both eyes. Because the experiment was performed on paired eyes, it was difficult to distinguish between the effects of the ophthalmic suspension and the control drop. The SPEED assessment was intended to measure symptoms over a period of weeks or months, so the immediate results may not accurately reflect the patient's symptoms. Finally, time of day was an uncontrolled variable in this study and may have influenced the symptoms reported by the patients.

[0133] In summary, this study demonstrated a significant increase in lipid layer thickness compared to the control group at a 4-hour interval in a physician-administered arm-length test. Notably, the eye drops were shown to increase tear film thickness by approximately 50% at the 4-hour time point in a controlled ocular patient assessment, and reduced patient-reported dry eye symptoms. These benefits were observed without significant impact on initial drop comfort or visual blurring.

[0134] As the wax acid ester particles dissolve, without being bound by any particular theory, it is believed that the oil bound to the wax acid ester particles is released into the tear film and migrates to the surface, continually replenishing the patient's diminished evaporative lipid barrier. Different sized particles dissolve at different rates. In effect, the widespread distribution of oil-bound wax acid ester particles creates a controlled release mechanism that delivers lipids to the tear film upon blinking as the wax ester particles dissolve. It is believed that the wax ester acts as a mechanism to slow the flow of the lipid layer through puncta during normal tear turnover.

[0135] Example 6 Ophthalmic suspensions compared with commercially available artificial tears A study was conducted to examine the on-eye performance of the eye drop vehicles listed in Table 1 in comparison to various commercially available artificial tear products (HyloCare®, Tears Again, Cationorm®, Hylovision®, Thealoz®, EvoTears®, TheraTears®, Systane® Complete, Systane® Balance, Soothe® XP, Retaine® MGD, and Refresh Optive® Advanced).

[0136] The lipid layer thickness measurements of the commercial products were performed up to 60 minutes. The measurement time of the ophthalmic vehicle was 120 minutes or more. The study was open-label, and Systane Ultra PF® was used as the control. A total of 93 observations (n=93) were performed among 12 commercial products. The results showed that in a 5-minute time interval, none of the products could increase the lipid layer thickness by 13 nm over the control, and the best commercial product showed an increase of 10 nm over the control in a 60-minute time interval.

[0137] On average, lipid layer thickness increased by 21 nm over the control over the 5 minute time interval and continued to increase to 24.7 nm at 60 minutes (n=78). Aggregated data are summarized in Tables 18 and 19.

[0138] [Table 18]

[0139] [Table 19]

[0140] In total, the eye drop vehicle showed a five-fold (5x) improvement in immediate lipid layer thickness increase over 78 cumulative observations compared to 93 cumulative observations for the 12 commercial products. This gap in lipid layer thickness increase was eleven-fold (11x) at the 60 minute mark, with the eye drop vehicle showing a 23 nm increase from baseline compared to the control, while the commercial products only showed a 2 nm increase from baseline compared to the control.

[0141] Example 7 tear film stability The wax ester containing oil-in-water suspension was compared to several other commercially available products.

[0142] Ophthalmic suspension containing beeswax: H714: 5.0 Dr‐21, 10.0% bees milk (beeswax, sesame oil, lecithin, methylparaben, and water) (Koster Keunen), 0.18 Tween‐80, 0.1 EDTA, and ba / NaCl 100 mOsm.

[0143] Water-soluble polymer solution #1: *DUASORB* (polymer system containing 0.1% dextran 70, 0.3% hydroxypropyl methylcellulose 2910), 0.001% polyquaternium-1, sodium borate, KCl, NaCl, HO, and HCl and / or NaOH.

[0144] Tear film performance was assessed using a standard contralateral eye experiment by observation of interference patterns. Delivery method: 5 subjects received approximately 50 μL of standard full drop solution in their eyes.

[0145] Wax ester formulation H714 vs. water-soluble polymer solution #1: H714 performed very well in the interference analysis of tear thickness. During the first 2 hours, H714 was 2.5 grades above baseline, returning to baseline after 3 hours. Meanwhile, in one set of experiments, the water-soluble polymer solution was initially 2.0 grades above baseline, but this quickly disappeared within 30 minutes. In another set of experiments, after instillation, both H714 and the water-soluble polymer were approximately 1.8 grades above baseline. After 15 minutes, the water-soluble polymer solution #1 was substantially back to baseline, whereas H714 (~1% beeswax) remained in the eye for over 2 hours. Water-soluble polymer #1, which showed an initial 2.0 score change, was substantially back to baseline after 1 hour. (See Figure 2).

[0146] Example 8 Zeta potential and ion mobility analysis Zeta potential testing was performed to evaluate particle performance and stability of various eye drop suspensions against the eye drop suspension marketed as Systane Balance. Zeta potential indicates the degree of electrostatic repulsion between similarly charged particles in a dispersion. Generally, a high negative zeta potential correlates with stability (e.g., the dispersion resists aggregation). With respect to eye drops, applicants have demonstrated that a higher negative potential translates directly into a longer residence time of the eye drop suspension on the eye.

[0147] To evaluate particle velocities generated by an electric field, ion mobility studies were performed on the same ophthalmic suspensions and Systane® Balance eye drops.

[0148] The contents of the eye drop suspensions tested (Samples A-F) are shown in Table 20. For Sample A, beeswax was added to the water phase and homogenized at 10,000 RPM for 2 minutes. For Sample B, beeswax was added to the water phase and homogenized at 20,000 RPM for 8 minutes. For Samples C and D, beeswax was added to the water phase and homogenized at 18,000 RPM for 8 minutes. For Samples E and F, the oil and water phases were separated, beeswax was added to the oil phase and homogenized at 18,000 RPM for 8 minutes and then tested. Systane® Balance eye drops contained propylene glycol (0.6%) as the primary lubricant, as well as various inactive ingredients including boric acid, dimyristoyl phosphatidylglycerol, disodium edetate, hydroxypropyl guar, mineral oil, polyoxyl 40 stearate, POLYQUAD® (polyquaternium-1) 0.001% preservative, sorbitan tristearate, sorbitol, and purified water, as well as hydrochloric acid and / or sodium hydroxide for pH adjustment.

[0149] The effect of zeta potential and ion mobility studies are shown in Table 21. [Table 20]

[0150] [Table 21]

[0151] Ophthalmic Suspensions A-F all exhibited a zeta potential of about -75 to about -95 and an ion mobility of about -6 to about -7.5. These results demonstrate that the ophthalmic vehicles provided herein provide significant stabilization of large particles as well as sustained thickening of the tear film, unlike those of Systane® Balance eye drops, which exhibited significantly different zeta potentials and ion mobilities.

[0152] Example 9 Suspension Separation Preparations of the formulas in Table 1 were allowed to sit for at least 2 hours. The formulas showed separation of the suspension showing distinct regions from the oil phase to the water phase. The formulas were then stained using solid oil red dye which preferentially stains the oils in the formula which are hydrocarbon oils but not the wax ester components. Microscopic examination of the phases showed distinct regions of the product separated, including an oil phase which primarily contained mineral oil along with isolated unstained wax particles having an estimated particle size of 200 to 500 nm with some larger particles larger than 2 microns. The samples separated into oil and water phases. Visual examination of each showed that the particles associated with the oil phase showed the primary activity associated with the extended time the product enhanced lipid layer thickness.

[0153] Example 10 USP(87) Biological Reactivity Test - Benzalkonium Chloride (BAK) Tests were conducted by an independent third party to measure the cytotoxicity of benzalkonium chloride (BAK) when used as a preservative in a standard topical saline eye drop solution vehicle. Test solutions of BAK in various dilutions at a representative preservative concentration used in ophthalmic products (50 ppm) were subjected to the USP(87) Biological Reactivity Test and graded according to reactivity. All solutions contained EDTA as an adjuvant that allows BAK to be active against gram-negative bacteria. All negative and positive controls were nominal. All test solutions were graded as exhibiting "severe" reactivity; that is, all cell layers were almost completely destroyed, so the use of BAK did not meet the USP requirements. Thus, the conclusion is that BAK (with EDTA) at 5% of the "use concentration" of a typical ophthalmic formulation caused severe reactivity according to the USP(87) Biological Reactivity Test.

[0154] It should be understood that the above description is merely representative of exemplary embodiments and examples. For the convenience of the reader, the above description has focused on a limited number of representative examples of all possible embodiments that teach the principles of the present disclosure. The specification does not attempt to exhaustively list all possible variations or combinations of these variations that are described. If alternative embodiments are not presented for a particular part of the disclosure, or even if alternative embodiments that are not further described for a part may be available, this is not considered a disclaimer of those alternative embodiments. Those skilled in the art will understand that many of the embodiments that are not described involve differences in technology and materials, rather than differences in the application of the principles of the disclosure. Thus, the present disclosure is not intended to be limited to less than the scope and equivalents set forth in the following claims.

[0155] Although the present disclosure has been described in conjunction with its detailed description, it should be understood that the foregoing description is intended to illustrate, but not to limit, the scope of the invention. Other aspects, advantages, and modifications are within the scope of the following claims.

[0156] General Description of Disclosure The following numbered statements provide a general description of the disclosure and are not intended to limit the scope of the appended claims.

[0157] Description 1. There is provided an ophthalmic suspension comprising: i) an aqueous phase comprising water and one or more components selected from the group consisting of at least one wax ester, at least one anionic polar surfactant, at least one nonionic surfactant, at least one salt, and at least one phosphate; and ii) an oil phase comprising at least one mineral oil, and optionally at least one wax ester. The wax ester exhibits an average particle size of at least about 5.0 microns using a Microtrack Particle Analyzer procedure for determining particle size.

[0158] Description 2. The present disclosure provides an ophthalmic emulsion suspension according to description 1.

[0159] Statement 3. The present disclosure provides an ophthalmic suspension according to any one of statements 1 to 2, wherein the ophthalmic suspension has an osmolality of about 245 mOsmol / kg to about 315 mOsmol / kg.

[0160] Statement 4. The present disclosure provides an ophthalmic suspension according to any one of statements 1 to 3, wherein the ophthalmic suspension is formulated as a free flowing emulsified vehicle at about 30°C.

[0161] Statement 5. The present disclosure provides an ophthalmic suspension of any of statements 1-4, wherein the wax ester is present in a concentration of about 0.8% to about 1.2% by weight.

[0162] Statement 6. The present disclosure provides an ophthalmic suspension according to any one of statements 1 to 5, wherein the wax ester is natural beeswax.

[0163] Statement 7. The present disclosure provides an ophthalmic suspension according to any one of statements 1 to 6, wherein the ophthalmic suspension exhibits a negative zeta potential of about -60 mV to about -110 mV.

[0164] Statement 8. The present disclosure provides an ophthalmic suspension according to any one of statements 1 to 7, wherein the ophthalmic suspension exhibits an ion mobility of about -5.9 (μms) / (V / cm) to about -7.4 (μms) / (V / cm).

[0165] Statement 9. The present disclosure provides an ophthalmic suspension according to any one of statements 1 to 8, wherein the oil is a mixture of light and heavy mineral oils.

[0166] Description 10. The present specification relates to a method for manufacturing a light mineral oil having a viscosity of about 3.0 mm at 40° C. 2 s ‐1 from about 34.4 mm 2 s ‐1 and the heavy mineral oil has a kinematic viscosity of about 34.5 mm at 40° C. 2 s ‐1 From about 150 mm 2s ‐1 The present invention provides an ophthalmic suspension according to any one of claims 1 to 9, which has a kinetic viscosity of

[0167] Statement 11. The present disclosure provides an ophthalmic suspension of any of statements 1 to 10, further comprising an anionic polar surfactant comprising a mixture of a polysorbate nonionic surfactant at a concentration of about 0.35 to about 0.45% by weight and an anionic polar dimyristoyl phosphatidylglycerol at a concentration of about 0.35 to about 0.55% by weight.

[0168] Statement 12. The present disclosure provides an ophthalmic suspension of any of statements 1 to 11, packaged in a sterile multi-use or sterile single-use container.

[0169] Statement 13. The disclosure provides an ophthalmic suspension of any of statements 1-12, packaged in a multi-dose non-preserved (MDNP) container or a container containing at least one preservative.

[0170] Statement 14. The present disclosure provides an ophthalmic suspension of any of statements 1 to 13, wherein the ophthalmic suspension increases the lipid layer thickness by at least 20 nanometers 5 minutes after administration.

[0171] Statement 15. The disclosure provides an ophthalmic suspension of any of statements 1-14, wherein the ophthalmic suspension increases the lipid layer thickness by at least 20 nanometers 4 hours after administration.

[0172] Description 16. A method for increasing lipid layer thickness is provided, comprising administering an ophthalmic suspension according to any one of claims 1 to 15 to the eye of a patient in need of treatment.

[0173] Statement 17. The present disclosure provides a method of increasing lipid layer thickness of statement 16, wherein the lipid layer thickness is increased by at least 20 nm within 5 minutes after administration.

[0174] Description 18. The present disclosure provides a method for increasing lipid layer thickness according to any of descriptions 16 to 17, wherein the lipid layer thickness is increased by at least 20 nm 4 hours after administration.

[0175] Description 19. The present disclosure provides a method of lubricating an eye, comprising administering to an eye of a patient in need of treatment an ophthalmic suspension of any of descriptions 1-15.

[0176] Description 20. The present disclosure provides a method for relieving symptoms of dry eye, comprising administering to the eye of a patient in need of treatment an ophthalmic suspension of any of descriptions 1-15.

[0177] Description 21. Provided is an ophthalmic suspension comprising a wax dispersion comprising (a) water, (b) at least one oil, (c) a surfactant, and (d) at least one wax ester present at a concentration of about 0.5 to about 1.5% by weight. The at least one wax ester in the ophthalmic suspension binds with the mucin layer, the aqueous layer, and the lipid layer of a subject's eye and acts to maintain or enhance the integrity of the stromal layer between the mucin layer and the aqueous layer, and the stromal layer between the aqueous layer and the lipid layer.

[0178] Statement 22. The present disclosure provides the ophthalmic suspension of statement 21, wherein the at least one wax ester acts to increase the thickness of the mucin layer, the aqueous layer, the lipid layer, or a combination thereof.

[0179] Description 23. The present disclosure provides an eye drop suspension according to descriptions 21-22, wherein the binding and homeostasis provided by the wax, wax ester or hydrolysis product allows the mucin layer, aqueous layer, and lipid layer of the tear film to interact with each other to maintain the tear film on the eye for an extended period of time (e.g., at least 2 hours).

[0180] Description 24. An ophthalmic suspension is provided that exhibits a zeta potential of about -60 mV to about -110 mV.

[0181] Description 25. An eye drop suspension is provided which upon contact with the eye separates into an oil phase and an aqueous phase and forms a metastable emulsion that provides lubrication to the eye for about 2 to about 12 hours.

[0182] Item 26. There is provided a method for relieving a symptom of dry eye, comprising the step of contacting an eye with the ophthalmic suspension according to any one of Items 21 to 25.

[0183] Statement 27. The present disclosure provides a method of relieving dry eye symptoms as described in statement 26, wherein upon contact with the eye, the ophthalmic suspension interacts with the lipid layer, the aqueous layer, the mucin layer, the interface between the lipid layer and the aqueous layer, and the interface between the aqueous layer and the mucin layer of the eye, and with unprotected corneal cells.

[0184] Description 28. The present disclosure provides a method for relieving dry eye symptoms according to any of descriptions 26 to 27, wherein the wax ester of the ophthalmic suspension is natural beeswax or synthetic beeswax.

[0185] Statement 29. The present disclosure provides a method for relieving dry eye symptoms of any of statements 26-28, wherein the oil is a mixture of lighter and heavier mineral oils.

[0186] Description 30. The present disclosure provides a method for relieving dry eye symptoms of any of descriptions 26 to 29, wherein the oil is present in a concentration of about 1.0% to about 5% by weight.

[0187] Description 31. The present disclosure provides a method for relieving a symptom of dry eye according to any of descriptions 26 to 30, wherein the surfactant is a mixture of two or more surfactants.

[0188] Statement 32. The present disclosure provides a method of relieving a symptom of dry eye of any of statements 26 to 31, wherein (i) the oil is a mixture of lighter and heavier oils and is present in a concentration of about 1.0 to about 5.5% by weight, (ii) the surfactant is a mixture of polysorbate 80 at a concentration of about 0.35 to about 0.45% by weight and dimyristoyl phosphatidylglycerol at a concentration of about 0.3 to about 0.5% by weight, (iii) the wax ester is natural or synthetic beeswax present at a concentration of about 0.5 to about 1.0% by weight, and the ophthalmic suspension has an osmolality of about 245 to about 310 mOsmol / kg.

[0189] Description 33. The present disclosure provides a method for relieving dry eye symptoms of any of descriptions 26 to 32, wherein the ophthalmic suspension is packaged in a sterile multi-use or sterile single-use container.

[0190] Statement 34. The present disclosure provides a method for relieving dry eye symptoms of any of statements 26-33, wherein the ophthalmic suspension is packaged in a multi-dose non-preserved (MDNP) container or a container containing at least one preservative.

[0191] Statement 35. The present disclosure provides a method for preparing an ophthalmic suspension comprising the steps of: (a) preparing a wax ester and a surfactant in a purified or deionized water vehicle; (b) preparing an oil-in-water emulsion comprising an oil in a purified or deionized water vehicle; (c) separately autoclaving the beeswax dispersion and the oil-in-water emulsion; and (d) aseptically blending the autoclaved beeswax dispersion and the oil-in-water emulsion to prepare a metastable oil-in-water emulsion suspension.

[0192] Statement 36. The present disclosure provides a method of preparing an ophthalmic suspension of statement 35, which provides lubrication on the eye for at least about 2 hours.

[0193] Statement 37. The present disclosure provides a method for preparing an ophthalmic suspension according to any one of statements 35-36, which provides lubrication to the eye for at least about 12 hours.

[0194] Statement 38. The present disclosure provides a method for preparing an ophthalmic suspension according to any of statements 35 to 37, wherein upon contact with the eye, the ophthalmic suspension penetrates the lipid layer, the aqueous layer, the mucin layer, the interface between the lipid layer and the aqueous layer, and the interface between the aqueous layer and the mucin layer of the eye and unprotected corneal cells.

[0195] Description 39. The present disclosure provides a method for preparing an ophthalmic suspension according to any one of descriptions 35 to 38, wherein the wax ester is natural beeswax.

[0196] Description 40. The present disclosure provides a method for preparing an eye drop suspension according to any one of descriptions 35 to 39, wherein the beeswax is synthetic beeswax.

[0197] Description 41. The present disclosure provides a method for preparing an ophthalmic suspension according to any of descriptions 35 to 40, wherein the oil is a mixture of a lighter oil and a heavier oil.

[0198] Description 42. The present disclosure provides a method for preparing an ophthalmic suspension according to any one of descriptions 35 to 41, wherein the surfactant is a mixture of two or more surfactants.

[0199] Statement 43. The present disclosure provides a method for preparing an ophthalmic suspension according to any of statements 35 to 42, wherein (i) the oil is a mixture of light and heavy oils and is present at a concentration of about 1.0 to about 5.5% by weight, (ii) the surfactant is a mixture of polysorbate 80 at a concentration of about 0.35 to about 0.45% by weight and dimyristoyl phosphatidylglycerol at a concentration of about 0.3 to about 0.5% by weight, and (iii) the wax ester is natural or synthetic beeswax present at a concentration of about 0.25 to about 1.0% by weight, and the ophthalmic suspension vehicle has an osmolality of about 245 to about 310 mOsmol / kg.

[0200] Description 44. The present disclosure provides a method for preparing an ophthalmic suspension according to any one of descriptions 35 to 43, wherein the ophthalmic suspension is packaged in a sterile multi-use or sterile single-use container.

[0201] Statement 45. The present disclosure provides a method of preparing an ophthalmic suspension of any of statements 35-44, wherein the ophthalmic suspension is packaged in a multi-dose non-preserved (MDNP) container or a container that includes at least one preservative.

[0202] Description 46. The present disclosure provides a method for preparing an ophthalmic suspension according to any one of descriptions 35 to 44, comprising packaging the ophthalmic suspension in a container containing a preservative.

[0203] Description 47. The present disclosure provides a method for preparing an ophthalmic suspension according to any of descriptions 35 to 46, wherein the wax ester acts to increase the thickness of the mucin layer, the aqueous layer, the lipid layer, or a combination thereof.

[0204] Description 48. The present disclosure provides a method for preparing an ophthalmic suspension according to descriptions 35-47, wherein the binding and homeostasis enabled by the wax esters allows the mucin layer, the aqueous layer, and the lipid layer of the tear film to interact with each other and the tear film to remain on the eye for at least 2 hours.

[0205] Statement 49. The present disclosure provides a method of preparing an ophthalmic suspension, comprising: (a) preparing an oil phase; (b) preparing an aqueous phase; (c) mixing the oil phase and the aqueous phase to form the ophthalmic suspension; and (d) autoclaving the ophthalmic suspension.

[0206] Statement 50. The present disclosure provides the method of preparing an ophthalmic suspension of statement 49, wherein the step of preparing the oil phase (e.g., heavy mineral oil and light mineral oil) comprises heating to a temperature of about 63°C to about 71°C.

[0207] Statement 51. The present disclosure provides a method for preparing an ophthalmic suspension according to statements 49 to 50, wherein the step of preparing the oil phase comprises adding or introducing at least one wax acid ester to the oil phase, followed by heating the mixture to a temperature above the melting point of the wax ester (e.g., about 63°C to about 71°C).

[0208] Description 52. The present disclosure provides a method for preparing an ophthalmic suspension according to any one of descriptions 49 to 51, wherein the aqueous phase can be prepared by mixing at least one wax ester, at least one salt, at least one phosphate, at least one surfactant and any other water-soluble components, and then heating the mixture to a temperature above the melting point of the wax ester (e.g., about 63°C to about 71°C).

[0209] Statement 53. The present disclosure provides a method for preparing an ophthalmic suspension according to statements 49-52, wherein the individual oil and aqueous phases are not autoclaved separately before being combined.

[0210] Description 54. The present disclosure relates to a wax dispersion comprising natural beeswax particles, an anionic polar surfactant, and water; Sodium hyaluronate, and oil-in-water emulsions, which contain oil and water; Optionally, at least one preservative selected from the group consisting of polyhexamethylene biguanide, stabilized oxychloro complexes, and polyquaternium-1; An ophthalmic suspension comprising: (i) the oil is a mixture of lighter and heavier molecular weight mineral oils and is present in a concentration of about 4.0 to about 6.25 weight percent; (ii) the anionic polar surfactant is a mixture of polysorbate 80 at a concentration of about 0.35 to about 0.45% by weight and anionic polar dimyristoylphosphatidylglycerol at a concentration of about 0.35 to about 0.50% by weight; (iii) natural beeswax particles are solid up to about 60° C. and are present in a concentration of about 0.50 to about 1.25% by weight; Here, the vehicle of the ophthalmic suspension is (i) upon contact with the eye, it forms a metastable emulsion that separates into an oil phase and an aqueous phase; (ii) providing a residence time on the eye of at least 2 hours; (iii) formulated as a free-flowing liquid at room temperature; (iv) an osmolality of about 230 mOsmol / kg to about 260 mOsmol / kg; (v) having a pH of about 6.5 to about 7.8.

[0211] Statement 55. The present disclosure provides the ophthalmic suspension of statement 54., wherein the beeswax is present in a concentration of about 1.0% by weight.

[0212] Statement 56. The present disclosure provides an ophthalmic suspension according to statements 54-55, wherein the beeswax is Cera Alba or Cera Flava.

[0213] Description 57. The present disclosure provides an ophthalmic suspension according to any one of claims 1 to 56, packaged in a sterile, single-use container.

[0214] Statement 58. The disclosure provides an ophthalmic suspension of statements 1-56 packaged in a sterile multi-dose container.

[0215] Description 59. The present disclosure provides a finished pharmaceutical product comprising an ophthalmic suspension vehicle according to any one of claims 1 to 56.

[0216] Description 60. The present disclosure provides a finished pharmaceutical product comprising an ophthalmic suspension vehicle according to any one of claims 1 to 56.

[0217] Description 61. The present disclosure provides a finished pharmaceutical product comprising an ophthalmic suspension vehicle according to any one of claims 1 to 56.

Claims

1. i) an aqueous phase comprising water and one or more components selected from the group consisting of at least one wax ester, at least one anionic polar surfactant, at least one nonionic surfactant, at least one salt, and at least one phosphate; ii) an oil phase comprising at least one mineral oil and, optionally, at least one wax ester; An ophthalmic suspension comprising: An ophthalmic suspension, wherein the suspension exhibits an average particle size of at least about 2.0 microns.

2. 10. The ophthalmic suspension of claim 1 having a mean particle size distribution of at least about 2.0 microns to about 20.0 microns.

3. 10. The ophthalmic suspension of claim 1, wherein the ophthalmic suspension has an osmolality of about 245 mOsmol / kg to about 315 mOsmol / kg.

4. 10. The ophthalmic suspension of claim 1, wherein the ophthalmic suspension is formulated as a free flowing emulsified suspension at about 30°C.

5. 2. The ophthalmic suspension of claim 1, wherein the wax ester is present at a concentration of about 0.8% to about 1.2% by weight.

6. 2. The ophthalmic suspension of claim 1, wherein the ophthalmic suspension exhibits a negative zeta potential of about -60 mV to about -110 mV.

7. 2. The ophthalmic suspension of claim 1, wherein the ophthalmic suspension exhibits an ion mobility of about -5.9 (μms) / (V / cm) to about -7.4 (μms) / (V / cm).

8. 2. The ophthalmic suspension of claim 1, wherein the oil is a mixture of light and heavy mineral oils.

9. The light mineral oil has a viscosity of about 3.0 mm at 40° C. 2 s ‐1 Approximately 34.4 mm 2 s ‐1 and the heavy mineral oil has a kinematic viscosity of about 34.5 mm at 40° C. 2 s ‐1 From about 150 mm 2 s ‐1 9. The ophthalmic suspension of claim 8, which exhibits a kinematic viscosity of

10. 10. The ophthalmic suspension of claim 1, further comprising an anionic polar surfactant comprising a mixture of a polysorbate nonionic surfactant at a concentration of about 0.35 to about 0.45% by weight and an anionic polar dimyristoyl phosphatidylglycerol at a concentration of about 0.35 to about 0.55% by weight.

11. 10. The ophthalmic suspension of claim 1 packaged in a sterile multi-use container or a sterile single-use container.

12. 10. The ophthalmic suspension of claim 1 packaged in a multi-dose non-preserved (MDNP) container or a container containing at least one preservative.

13. 10. The ophthalmic suspension of claim 1, wherein the ophthalmic suspension increases the lipid layer thickness by at least 20 nanometers 60 minutes after administration.

14. 10. The ophthalmic suspension of claim 1, wherein the ophthalmic suspension increases the lipid layer thickness by at least 20 nanometers two hours after administration.

15. 1. A method for maintaining the integrity of the tear film of an eye, comprising increasing the thickness of the lipid layer of the eye, the method comprising: administering the ophthalmic suspension of claim 1 to the eye of a patient in need of treatment; A method comprising:

16. 16. The method of claim 15, wherein the integrity of the tear film is maintained and the lipid layer thickness is increased by at least 20 nm 60 minutes after administration.

17. 1. A method for reforming or building one or more layers of the tear film of the eye, comprising: administering the ophthalmic suspension of claim 1 to an eye of a patient in need of treatment; The ophthalmic suspension, upon administration, reforms or reconstitutes one or more layers of the eye's tear film.

18. 1. A method for lubricating an eye, comprising: administering the ophthalmic suspension of claim 1 to an eye of a patient in need of treatment; The ophthalmic suspension, upon administration, reforms or reconstructs one or more layers of the eye's tear film and maintains tear film integrity for 60 minutes.

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