LIMITED-DOSE DISPENSER FOR OPHTHALMIC SOLUTIONS

Abstract: A solution-dispensing system is disclosed comprising a sealed container forming an interior chamber to hold an absorbent material holding a sufficient amount of ophthalmic solution for at least one dose of the solution in the form of droplets. The absorbent material is positioned in said chamber such that a converging end portion protrudes from an opening in the container after removing a separable portion of an envelope. The converging portion of said absorbent material forms drops when the package is held with the opening facing down and opposite sides of the package and pressed.

Description: LIMITED-DOSE DISPENSER FOR OPHTHALMIC SOLUTIONS BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a limited-dose dispenser for applying an ophthalmic solution to the eye. The dispenser comprises a sealed package containing an absorbent material soaked with the ophthalmic solution such that when an end portion of the package is removed, the ophthalmic solution can be manually squeezed from the absorbent material onto the eye in the form of droplets. Description of the Related Art There are a number of temporary or chronic eye conditions that can cause sore, inflamed, red, irritated, dry, itching, and/or burning eyes. Ophthalmic products used for the topical treatment of such conditions include anti-histamines or other allergy drugs, antibiotics, anti-inflammatories, medicines for the treatment of glaucoma or ocular hypertension, and artificial tears for dry eyes. In addition, many people who wear contact lenses for visual correction or physical appearance may occasionally experience lens discomfort due to a dry feeling. Ophthalmic solutions for rewetting or lubricating contact lenses may be applied in the form of drops to a contact lens while worn in the eye in order to provide temporary relief. Typically, dispensers for these types of solutions are small plastic bottles with a dispensing or drop-forming tip. A dispenser may be designed to be used multiple times over a number of days, in which case a preservative or disinfectant is typically employed to maintain the solution safe for repeated use, so that the solutions remains protected against accidental contamination. However, there are certain disadvantages to having a disinfectant in an ophthalmic solution applied to eye in the form of droplets. First, chemical disinfecting agents tend to be irritating, and it is desirable that ophthalmic solutions be as gentle as possible, especially if the drops are intended to comfort eyes. Second, the eye and its surrounding tissue are particularly sensitive, and many people require hypoallergenic formulations. This makes the formulation of multi-dose solutions difficult, and in some cases, people may still have adverse reactions. An alternative to preserved multi-dose solutions are preservative-free unit-dose systems in which the solutions may be sterilized either prior to packaging or after packaging. Once the dispenser is opened and used, the solution inside should be used within a relatively short time, typically 24 hours or less. Often, such solutions are intended to be used once and, thereafter, the dispenser and any remaining solution is discarded. Unit-dose products are typically packaged in small bottles that are smaller than multi-dose dispensers. A bottle tip is usually used to help dispense the solution to the eye area. Both the bottle and tip may be integrally molded plastic. Potential problems with such small bottles exist due to its small size and difficulty of handling. The bottle may be difficult to squeeze, and the tip is a potential danger to the eye. A typical size for a bottle of ophthalmic solution is 15 ml or less. Unit-dose containers typically have smaller volumes (usually 0.3 ml to 1.0 ml) and are known as "form- filled seal" containers. These types of containers are usually made from a high or low density plastic. The bottle may be anywhere from less than half full to completely full with solution. A dilemma is that relatively smaller unit-dose bottles may be more difficult to handle and squeeze, while relatively larger unit-dose bottles contain more empty space or more wasted solution. The cost of shipping any solution entails expense, and there is added cost if the solution is packaged in a bottle that is only partially filled. Cylindrical bottles in general already leave a significant amount of empty space in the container. Furthermore, partially filled bottles not packaged under vacuum pose the additional problem of evaporation, which can affect the concentration of the active ingredients contained in the solution which in turn can affect the efficacy or other properties of the product. On the other hand, if a bottle contains a substantial excess of ophthalmic solution, a consumer may be tempted to use the solution for longer than recommended, even if the bottle contains an unpreserved ophthalmic solution intended for unit-dose application. If the tip touches the ocular area during use, however, it is possible for bacteria to then be transferred to the solution, where it can proliferate, and then potentially be transferred back to the consumer's eyes. It is also not unusual for family members to share bottles, in which case repeated use of unit-dose solutions can spread infections. Not only preservative-free unit-dose containers, but sample bottles in general for ophthalmic solutions tend to contain a relatively small amount of solution. Sample bottles, regardless of whether they contain preserved or unpreserved solutions, have been used to provide samples of products to potential customers for trial use. Sample bottles distributed for free to potential customers, unlike products that are commercially sold, intentionally contain an amount of solution for treatment over a limited period of time. For example, it would be undesirable for a sample bottle of allergy drops to contain a sufficient amount of solution to last an entire allergy season. Finally, the bottles that have been conventionally used for dispensing ophthalmic solutions in the form of a limited amount of droplets, even though small, are not always convenient to carry, especially in a pocket or wallet. The smaller the size of the dispenser, the more difficult it is to grasp and handle for dispensing, while the larger the size of the dispenser, the greater the inconvenience to carry it around in one's personal possession. Various bottles have been disclosed for dispensing ophthalmic solutions. US Patent No. 5,238,157 discloses a package that is impermeable and completely inert with respect to the package contents and environment comprising stiff paper or cardboard that has been coated with plastic, metal foil, or the like. US Patent Number D237,942 discloses a common type of container with a breakable cap. This design is similar to a number of containers or dispensers that are currently used to hold unit-dose ophthalmic solutions. This type of dispensing bottle typically has an elongated body, a narrowing of the upper body to form a dispensing tip for drop formation, and a frangible, removable tab for opening the bottle at the time of use. Once the bottle is opened, the solution is dispensed by pressing the lateral sides of the bottle. The bottle is then thrown away, as it can not be recapped. The volume of this container tends to be very small, and the container itself is made of a somewhat pliable plastic material. This container can be packaged individually or collectively. An array of containers can be formed, for example, by having the containers attached to each other on their lateral sides. Further examples of such containers can be found in US Pat. Nos. D362,304; D312,209 and D255.492. Although not in the field of ophthalmic products, US Patent No. 4,998,984 discloses a prepackaged single-use disposable wiper pad that is saturated with a liquid. These pads have multiple uses, including the sanitation of surfaces such as telephone mouthpieces or the cleansing of infants' hands or buttocks. Other patents which disclose prepackaged and premoistened disposable articles include US Pat. Nos. 4,601,081, 4,117,187 and 4,781,974. US Patent No. 4,627,936 discloses a product comprising a wiper pad sealed in a moisture and light-impermeable barrier packet or envelope. A nozzle is inserted into an open end of the envelope, a measured quantity of the solution is injected into the envelope, and the envelope is sealed. The wiper becomes saturated with the solution by capillary action. The wiper is readily available for use by tearing open the envelope. US Patent No. 4,437,567 discloses a method of sterilizing products in sealed packages, particularly medical or surgical products. The package can be fabricated of any conventional material. One embodiment involves two laminated sheets bonded together along their margins by a suitable adhesive to form a hermetically sealed package. U.S. Patent No. 4,150,744 discloses packaging for a light-sensitive and oxygen- sensitive solution. The solution is packaged in a gas-impermeable envelope, preferably a three component laminate of nylon, aluminum foil, and polypropylene. U.S. Patent Number 3,369,656 discloses a disposable container for storing and treating contact lenses. The container is fabricated with a pair of flexible, liquid impervious sheets. Inside a soft internal fabric is soaked in solution suitable for treating contact lenses. In view of the above, there exists a need for a lighter, more compact package for ophthalmic products that is easier for the consumer to carry and handle and that is safer to use. At the same time, there is a need for a container for unpreserved sterile ophthalmic drops that has neither an excess amount of solution that is subject to misuse, nor has excess empty space or wastage in the container. Finally, there is also a need for a improved dispenser that allows a consumer to "sample" an ophthalmic product for topical treatment to the eye in the form of eye drops. SUMMARY OF THE INVENTION The present invention is directed to a solution-dispensing system comprising a sealed container forming an interior chamber to hold an absorbent material in which is absorbed a sufficient amount of ophthalmic solution for at least one dose of the solution in the form of droplets. The absorbent material is positioned in said chamber such that a converging portion protrudes from an opening after removal of an end portion; which converging portion of said absorbent material forms drops when the package is held with the opening facing down and opposite sides of the package are digitally pressed. In one embodiment of the invention, the package is formed by at least two sheets of liquid-impervious material, said at least two sheets sealingly attached to each other, preferably at the outer edges of each of two sheets. The package is opened by tearing across a line joining two sealed edges of the package. The absorbent material is positioned inside the package so that an edge portion protrudes from an opening after removal of an end portion of the package. In a second embodiment of the invention, the dispensing system comprises an elongated container having a round, square or rectangular cross-section in which the absorbent material has a substantially conical tip for the formation of droplets for application to the eye. DESCRIPTION OF THE DRAWING FIG. 1 illustrates a dispensing system according to the present invention including a package contained a pad in which is absorbed an ophthalmic solution and a tear-away portion for opening the package and exposing the pad for the application of droplets to the eye. FIG. 2 illustrates a cross-sectional view of the dispensing system of FIG. 1. FIG. 3 illustrates a second embodiment of the invention in which the dispenser is cylindrically shaped and the pad has a conical dispensing tip. FIG. 4 illustrates a cross-sectional view of the dispensing system of FIG. 3. DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a dispenser containing an ophthalmic solution that can be used for treating the eyes. It is preferred that the dispenser comprise a container having walls that are impermeable and completely inert with respect to the dispenser contents and the environment. With reference to the drawing in FIGS. 1 and 2, the container is generally indicated at 11 and can be fabricated from any conventional material such as plastic- coated metal, plastic film or sheet, plastic coated metal foil, metallized paper, or other packaging material impervious to liquid and inert to the contents of the container. In one embodiment of the invention, the container is a sealed gas-impermeable envelope or pouch that resists the entry of oxygen and the loss of water vapor, thereby rendering the combination storable for long periods of time. Most preferably, the envelope is a metal/polymer laminate, two layers of which can be heat-sealed, RF-sealed, ultra-sonically sealed, or adhesively sealed to form a pouch along the edges of the polymer surfaces. A typical laminate can have two layers but preferably possesses an additional outer polymer layer to facilitate abrasion resistance and printing. A typical three-layer laminate comprises, from the outside inwards, (i) a nylon, polyester, polyethylene or polypropylene layer for abrasion resistance, (ii) an aluminum-foil layer, and (iii) an inner heat-sealable polymer layer such as polyethylene, polypropylene, polyvinylidene chloride or nylon. The total thickness of the laminate is preferably about 25 μm to 250 μm, more preferably 50 μm to 125 μm in total thickness. The aluminum- foil layer is preferred for forming a water barrier that both protects the inner solution from outside contaminants and prevents harmful evaporation of the inner solution. The two polymer layers covering the sides of the aluminum foil in the preferred laminate forms an oxygen barrier and protects the aluminum from attack. The skilled artisan will appreciate, however, that other types of laminates, with or without aluminum, or even a non-laminate may be used to form a container according to the present invention. The envelope or pouch comprises a removable portion for opening the pouch in order to apply its contents. The removable portion can be designed to separate by various means, including a tear strip, tearing notch, line of weakness, or other expedient to facilitate opening of the pouch. For example polypropylene and polyethylene, which have linear directionality for tearing, can be used to form the outer and inner layers of a laminate. Referring to the embodiment of FIG. 1, the package has two cut out notches 13 located on opposite sides of the pouch to assist the tearing open of the pouch. An absorbent material 15 is contained within the pouch 11. Absorbent material is hereby defined as a solution-impregnated body made from an absorbent matrix material, preferably a foam or web material that reversibly holds an aqueous solution in an absorbed state until compressed. Preferably more than half, more preferably at least 80 percent by weight, most preferably essentially all of the solution in the container is absorbed by the solution-impregnated body in the final product and at steady state (until compressed). The solution-impregnated body is preferably saturated with the solution to maximize its storage capacity. The shape of the absorbent material can vary, including either flat pads or more-three dimensional configurations, for example symmetrical in cross-section. Preferably, at least for the latter configurations and with the exception of a converging end portion or tip for drop formation, the solution-impregnated body conforms to the shape of the container in order to minimize excess space. The absorbent material can be made of any suitable material that reversibly absorbs an ophthalmic solution by squeezing, for example a medical grade absorbent foam or fiber. It is important for ophthalmic use that the absorbent material be essentially particulate free and not generate particles or fibers that could be transferred to the eye where it could cause irritation. One way to prevent this is to remove any fibers in the absorbent material in the final product. Types of absorbent materials that have low particulate matter due to prewashing include cellulose, nylon and polyester fibers. As indicated above, various ophthalmic solutions that can be used in the present dispenser, including solutions for the treatment of allergy, dry eye, inflammation, infection, glaucoma and ocular hypertension. Such solutions also include moisture drops, artificial tears and solutions for wetting or otherwise treating contact lenses while worn in the eye. Due to the absorbent material, however, such solutions should not contain particles in suspension. The amount of solution contained in the dispenser is such that both eyes can be treated at least once. For example, if the treatment requires two drops per eye (30 to 50 μl), then the dispenser should contain sufficient solution to wet the absorbent material and easily dispense a total of at least 200 μl. In one preferred embodiment of the invention in FIGS. 1 and 2, the dispenser container is substantially flat, with square to rectangle side sides and the absorbent material is less than V" thick (0.635 cm). In order to facilitate handling, the side dimensions of a rectilinear package is preferably at least l Λ inch (1.27 cm) per side, for example, V" by Vi" (1.27 cm by 1.27 cm) but less than 3 inches (7.62 cm) per side. A preferred size is about 1 3 Λ" by 2 " (4.445 cm by 5.715 cm). It is also possible for other shapes to be used, for example a rectangular or square shape with rounded edges. In the embodiment of FIGS. 3 and 4, the container 21 for the absorbent material 23 has an elongated shape and a rounded cross-section as indicated in FIG. 4. The absorbent material is also rounded in cross-section and has a conical converging tip. When the tear away portion 27 is removed, the tip protrudes from an opening in the container such that it is capable of forming droplets when the container, and in turn the absorbent material, is squeezed. The drops can be applied to the eye as described herein for the treatment as described herein. One skilled in the art will readily appreciate that other conventional container shapes may be used, so long as opposite sides of the container can be squeezed. For example, the container and/or the absorbent material may be oval, rectangular, square, or hexagonal in cross-section. In manufacturing a dispenser according to the present invention, any of various conventional methods may be used. For example, an absorbent material may be first saturated with an ophthalmic solution and then encapsulated in the package, or alternatively the dispenser may be partially assembled and the solution dispensed to the absorbent material prior to the final sealing of the dispenser. Still alternatively, the absorbent material may be enclosed in a package or envelope in a dry condition and then injected with a measured amount of solution as described in U.S. Patent Number 4,627,936. The dispenser can be sterilized by methods commonly used in packaging ophthalmic solutions. Autoclaving and gamma irradiation are two methods of terminal sterilization. Pulsed-light sterilization is another alternative. A preferred method for sterilization of the dispenser and its contents is aseptic packaging under clean-room conditions. Whenever it is desirable to use the dispenser, it is only necessary to open the package and dispense. The package is devised to be inexpensive so that it is practical to be used to dispense drops to one eye and then to the other upon which it is easily discarded. The solution is dispensed by grasping the package between the thumb and fingers, preferably the forefinger. By pressing the thumb and finger together, the pad is squeezed and the liquid is expressed toward the opening, collecting on the converging end portion. Once enough liquid has collected on the converging end portion, a drop will form. The drop can be directed such that it falls onto the eye. The packaging of such a dispenser allows for flexibility. The dispenser can be packaged as a single unit or in multiple units. In the case of multiple units, a plurality of dispensers can form a strip with a single row of dispensers or a sheet with more than one row of dispensers, there being perforations or other means of separation between the individual units. A strip can be fan-folded or rolled up into a roll. The consumer could then sequentially remove the end unit for use. A strip may be rolled and placed inside a container to facilitate separation of the end unit. The consumer may then readily remove each unit dispenser as needed. An arrangement that is advantageous for shipping is one in which the dispensers form a plurality of flat strips or flat sheets so that they are stacked tightly together within a package. The dispenser according to the invention is ideally suited to be carried by a person in his or her immediate possession. Because of it's relatively small size, the dispenser can be easily stored and carried in a pocket, purse or brief case.

Claims: Claims 1. A ophthalmic-solution dispensing system comprising: (a) a sealed container forming an internal chamber, which container has a removable end portion, (b) an absorbent material within the internal chamber which absorbent material has a converging end portion, and (c) an sterile or preserved ophthalmic solution that is absorbed by the absorbent material, whereby by removing the separable end portion from the rest of the container to form an opening in the container, the converging end portion of the absorbent material protrudes from the opening such that when the container together with the absorbent material are manually squeezed and the converging end portion is held pointed downwards, droplets of ophthalmic solutions are formed for application to the eye. 2. The ophthalmic-solution dispensing system of claim 1, wherein the absorbent material is selected from the group consisting of urethane, cellulose, and nylon. 3. The ophthalmic-solution dispensing system of claim 1, wherein the solution is an ophthalmic solution for the treatment of dry eye. 4. The ophthalmic-solution dispensing system of claim 1, wherein the solution is for the treatment of allergy. 5. The ophthalmic-solution dispensing system of claim 1 , wherein the solution contains a therapeutic agent selected from the group consisting of drugs for the treatment of inflammation, infection, glaucoma, and ocular hypertension.. 6. The ophthalmic-solution dispensing system of claim 1, wherein the container is a unit-dose dispenser containing 30 to 400 μl of solution. 7. The ophthalmic-solution dispensing system of claim 7, wherein the container is a unit-dose dispenser containing 50 to 200 μL of solution. 8. The ophthalmic-solution dispensing system of claim 1 , wherein the sealed container is a pouch formed by at least two sheets of liquid-impervious material, said sheets sealingly attaching to each other around the outer edges to form the interior chamber, said separable end portion capable of removal by tearing across a line joining two edges of the pouch, and wherein the absorbent material is positioned in said internal chamber such that a converging edge portion protrudes from the opening formed by the removal of said separable edge portion. 9. The ophthalmic-solution dispensing system of claim 1, wherein the sealed container is elongated with a substantially rounded, square or rectangular cross-section, wherein the absorbent material is positioned in said internal chamber such that an substantially conical-shaped portion protrudes from an opening in the container after removal of said end portion. 10. An ophthalmic-solution dispensing system comprising: (a) a sealed pouch formed by two sheets of liquid-impervious material, said sheets sealingly attached to each other around the outer edges forming an interior chamber, said pouch having a separable end portion that can be separated by tearing across a line joining two edges of the pouch to form an opening in the pouch, after which the separable end portion may be discarded; (b) an absorbent pad holding an ophthalmic solution which absorbent pad is positioned in said internal chamber such that an edge portion protrudes from the opening formed by the removal of separable end portion, wherein the absorbent pad has a converging edge portion for the formation of drops when the pouch is held with the opening facing down and digitally pressing opposite sides of said package. 11. A method of applying drops of an ophthalmic solution to an eye by (a) removing an end portion of a container, thereby exposing a converging end portion of an absorbent material holding an ophthalmic solution; (b) positioning said converging end portion above and adjacent to the eye; and (c) digitally pressing opposite sides of the container together with the absorbent material to express liquid from the absorbent material onto the eye. 12. The method of claim 11, wherein the solution is an ophthalmic solution for the treatment of dry eye. 13. The method of claim 11 , wherein the ophthalmic solution is for the treatment of allergy. 14. The method of claim 11, wherein the ophthalmic solution contains a therapeutic agent selected from the group consisting of drugs for the treatment of inflammation, infection, glaucoma, and ocular hypertension.. 15. The method of claim 11, wherein the container is a unit-dose package containing 30 to 400 μl of solution. 16. The method of claim 11, wherein the container contains 50 to 200 μl of solution. 17. The method of claim 11, wherein the container is a unit-dose container that holds a sterile but unpreserved solution.

Inventors: SNITCHLER NORMAN C, SNITCHLER, NORMAN, C.
Applicants: BAUSCH & LOMB, BAUSCH & LOMB INCORPORATED
Application year: 1999
Main classification: A61F9
IPC codes: A61F9, A61J1, A61L12