Apparatus for removing preservatives from solutions

Abstract: There is presented a device for removing a preservative from ophthalmic and other solutions as the solution is dispensed from a container. The device preferably comprises a container having squeezable sidewalls defining a solution retaining chamber, but may also be an aerosol can or other container. The container also preferably includes a neck portion and a dispensing head having a container outlet on its end through which the solution is dispensed. Means for removing the preservative from the solution as the solution is dispensed from the chamber through the container outlet are also provided. This removing means preferably comprise scavenging material. The preservative is removed upon, contact with the scavenging material.

Description: The present invention relates to a fitment and to a dispensing device for removing a preservative from an ophthalmic solution according to the respective independent patent claim. Many solutions are available for making contact lenses more comfortable, safer, and easier to wear. For example, wetting solutions facilitate the wetting of a lens, soaking solutions serve as anti-microbial storage medium and prevent dehydration and distortion of the lens, and cleaning solutions remove accumulated eye secretions and other contaminants from lenses. A large number of other solutions are also used by contact lens patients. These ophthalmic solutions are typically marketed in squeezable plastic containers or aerosol cans having a nozzle through which the solution is dispensed. Containers for storing and dispensing fluent medicaments in general are known, for example, from US-A-3,760,987. In this reference a snap assembled dispensing device is disclosed, which is provided with a membrane filter at its outlet in order to filter particulate matter from the medicament solution as the solution is dispensed. Containers for storing and dispensing ophthalmic solutions in particular are known, for example, from DE-U-86 22 273. In this reference a container is disclosed, in which the ophthalmic solution is stored and which is provided at its outlet with a porous filter, the surface of which has an anti-bacterial layer in order to prevent bacteria from entering the solution stored in the container thus preventing bacterial growth within the ophthalmic solution. EP-A-0 366 534, which is a document under Article 54(3) EPC, describes a package for a liquid to be purified. The package comprises a container having a neck which surrounds a lock-chamber for receiving at least one element for the treatment of the liquid when it is discharged from the container. The lock-chamber is rigidly fixed to an obturator or movable plug which is capable of displacement at least at the time of initial use between a storage position in which it isolates the interior of the container from the lock-chamber and a position of use in which it establishes a communication between the interior of the container and the interior of the lock-chamber. The obturator or plug remains rigidly fixed to the lock-chamber which has a constant internal volume. In the liquid there may be dissolved a preservative. Because these solutions come in contact either directly or indirectly with the eye, it is very important that they be free of microbial growth. To this end, it is common practice for preservatives to be provided in these solutions. Among the preservatives used in ophthalmic solutions are polymoxin B sulfate, quaternary ammonium compounds, chlorobutanol, organic mercurials, p-hydroxybenzoic acid esters, and certain phenyls and substituted alcohols. A problem exists, however, in that the preservatives used in the ophthalmic solutions can cause eye irritation if used in high concentrations. For example, benzalkonium chloride (BAK) is used as a preservative in ophthalmic solutions and has broad anti-bacterial and anti-fungal activity when used with other components, such as disodium ethylene diaminetetraacetic acid (EDTA). However, it has been reported that repeated use of BAK can denature the corneal protein and cause irreversible eye damage. Also, in addition to chemical sensitivity, a number of contact lens wearers have allergic reactions to the preservatives used in ophthalmic solutions, even at relatively low concentrations. The typical remedy for overcoming chemical sensitivity and allergic reactions to preservatives in ophthalmic solutions entails switching the patients to an unpreserved solution. However, unpreserved solutions present problems in marketing, as well as in home storage, in that once the container housing the solution is opened, the solution quickly becomes contaminated and unsuitable for further use. They also tend to be very expensive to produce. Therefore, there exists a need for an apparatus which removes preservatives, as well as other components, from a solution as the solution is dispensed to a patient. There exists a further need for such an apparatus which is easily manufactured and economical to use. There exists a further need for an apparatus which may be attached to a standard solution container. These needs have been met by providing a fitment and a dispensing device according to claim 1 or claim 8 respectively. The present invention provides a device for removing a preservative from ophthalmic and other solutions as the solution is dispensed from a container. The device preferably comprises a container having squeezable sidewalls defining a solution retaining chamber, but may also be an aerosol can or other container. The container also preferably includes a neck portion and a dispensing head having a container outlet on its end through which the solution is dispensed. Means for removing the preservative from the solution as the solution is dispensed from the chamber through the container outlet are also provided. The means for removing a preservative from the solution comprise a scavenging material provided within the path of the solution as the solution is dispensed. The device is a standard solution container housing a solution having the component to be removed, and the scavenging material is held within the dispensing head. The scavenging material may have a positive charge for scavenging negatively charged preservatives or it may have a negative charge for scavenging positively charged preservatives or it may be a material which selectively scavenges components by a size exclusion mechanism or it or may comprise any other means for removing a component from solution. A fitment is utilized having a fitment body which is releasably engagable with a standard solution container. The fitment includes passage means within its body for allowing passing of the solution from the container to a fitment outlet. In this embodiment, the means for removing a preservative comprises a scavenging material provided within the fitment so as to be within the path of the solution as the solution is dispensed from the container outlet to the fitment outlet. The fitment has the advantage of being able to be adapted to standard solution containers. Also, means for providing a control of the flow of solution out of the container is provided. A check valve is provided within the final dispensing outlet to prevent backflow of solution into the container following use. Additionally, means for regulating the flow of air into the container, namely, a second check valve, is placed within the neck portion of a squeezable container for allowing air to flow into a depressed container, thereby restoring the container to its original shape. This embodiment will minimize the incidence of microbial growth in the area of the dispensing head proximate the final dispensing outlet. Therefore, it is an object of the present invention to provide an improved apparatus which removes preservatives, as well as other components, from a solution as the solution is dispensed to a patient. It is also an object of the present invention to provide such an apparatus which is easily manufactured and economical to use. It is also an object of the present invention to provide such an apparatus which nay be adapted to a standard solution container. These and other objects and advantages will be more apparent from the following detailed description of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exploded view of an apparatus in which scavenging material is provided within a container; Figure 2 is a partial cross-sectional view of the apparatus in which scavenging material is provided within a container; Figure 3 is an exploded view of an apparatus in which scavenging material is provided within a fitment; Figure 4 is a partial cross-sectional view of an apparatus in which scavenging material is provided within a fitment; Figure 5 is a partial cross-sectional view of an apparatus in which the dispensing head is snap-fitted onto a container; and Figure 6 is a partial cross-sectional view of an apparatus according to the present invention having means for providing one-directional flow of solution out of a container. Referring to the figures, a device 10 for removing components, such as preservatives, from solutions, such as an ophthalmic solution, is shown. The device 10 includes a container 12, preferably constructed of moulded plastic, having resilient sidewalls 14 which define a solution retaining chamber and which preferably may be deformed by inward pressure to produce a pressure within the container 12 for using and dispensing its contents. The container 12 is provided with an upstanding neck portion 16 having external threads 13 thereabout. A dispensing head 20 is provided atop the neck portion 16, either integrally, as shown in Figs. 1-4, by threading engagement, or by snap-fitting engagement as shown in Figs. 5 and 6. A flange portion 22 is provided between the dispensing head 20 and the container neck 16. The dispensing head 20 and the container neck 16. The dispensing head 20 has passage means, such as a duct or other passageway, through its length which in turn has a first end in communication with the chamber and a container outlet 24 at the other end. Figs. 1 and 2 show means for removing preservatives or other components which are placed directly within the dispenser head 20. The preservative removing means comprises scavenging material 26 provided intermediate the chamber and the container outlet 24, so as to be within the path of the solution as the solution is dispensed from the container 12. The material 26 should be positioned as close as possible to the outlet 24 to minimize empty space in the upper portion of the dispensing head 20. The material 26 may be compressed into a porous mass which is preferably insert molded into the dispensing head 20. However, any other means of maintaining the material in the path of the solution may also be used. Alternatively, as shown in Fig. 2, the material 26 may be in the form of fine particles and held in place by porous supporting members 28 and 30. The members 28 and 30 may be made from porous plastic, such as porous polyethylene. In either case, it is important that the solution pass through the scavenging material 26 as it exits the container 12 so that the component is removed upon contact with the scavenging material 26. Figs. 3 and 4 show a fitment 32 having a body 34 which is affixable to a standard-size container 12, such as described above but without the scavenging material 26 within its dispensing head 20. The lower portion 36 of the fitment 32 is provided with internal threads 38 which complimentarily mate with threads 18 on the outer surface of the neck portion 16 so that the fitment 32 may be releasably matable to the container 12. As seen in Fig. 4, when the fitment 32 is in threaded relationship with the container neck portion 16, an internal flange 40 of the fitment 32 rests atop the neck portion 16 to provide a seal between the fitment 32 and container 12. The fitment 32 has a fitment outlet 42 atop a tapered upper section 44, as well as a passage or duct through its length. The passage is preferably adjacent to and in flow registration with the container outlet 24 at one end and opens to the fitment outlet 42 at its other end. In this alternative embodiment, the scavenging material 26 is provided within the fitment 32, and removes the component, such as preservative, from the solution as the solution passes from the container outlet 24 to the fitment outlet 42. As in the first embodiment, the scavenger material 26 may be in solid mass or powder or other form. Fig. 6 shows a device 10 of the present invention which includes means for providing one-directional flow of solution out of the container such as a check valve 52. Preferably, the valve 52 is a deformable, polymeric valve that is positioned within the container outlet 24 so as to be in flow communication with the interior portion of the dispensing head 20 at one end and with the atmosphere at a second end. In its normal or closed position, the valve 52 does not allow air or solution to flow into or out of the container 12. However, as a result of the pressure exerted onto the container 12 during use, the valve 52 moves to an open position that allows the solution to pass through to the atmosphere. When the pressure on the container 12 is stopped, the valve 52 closes and any solution remaining atop the valve 52 cannot be pulled back inside the container 12, thereby minimizing the incidence of organisms reentering the container 12 after use. Also, when a squeezable container 12 is used, means for drawing air into the container 12 is provided for returning the container 12 to its original shape. Preferably, a second one way check valve 54 is provided within the neck portion 16 and below the scavenging material 26. Upon release of the container 12 by the user, air is drawn into the container 12 by the valve 54, thereby restoring the container 12 to its proper shape. Also, because the valve 54 is one-directional, solution from within the container 12 cannot leak out to the atmosphere through the valve 54. Furthermore, because the second valve 54 is below the scavenging material 26, any organism which should happen to be withdrawn into the container will be deposited into the preserved solution and killed. Both the dispensing head 20 and the fitment 32 may include a closure cap 46. The closure cap 46 may have internal threads 48 capable of matingly engaging with either the threads 18 of the neck portion 16, as shown in Fig. 1, or the external threads 50 of the fitment 32, as shown in Fig. 3, and resting on flange 22. Of course, containers other than squeezable plastic types may be utilized. The scavenging material may be placed within an aerosol type dispenser, a solid bottle, or some other container. Virtually any type of scavenging material 26 for removing a preservative or other component from solution may be used. For example, removal of benzalkonium chloride or other quaternary ammonium compounds can be accomplished by an ionic exchange mechanism. The scavenging material 26 would preferably be an inert material with a negative charge, and the positively charged quaternary ammonium compound would adhere to the material 26 as it flows through the fitment 32 or dispensing head 20, depending on the embodiment. Examples of products capable of removing positively charged preservatives such as BAK include AG-50X-8, AG-50X-16, BIO-BS-SM2, and BIO REX70, all available from BIO-RAD Laboratories, Richmond, California and Acropor 5A-6404 available from Gelman Sciences, Ann Arbor, Michigan. Similarly, negatively charged components, such as acids, may be removed by using positively charged scavenging material 26. Examples of such scavenging material includes AG-1, AG-2X8, and AG-10 Alumina from BIO-RAD Laboratories. For example, it has been found that scavenging material 26 comprising Chelex 100 from Bio Rad will remove Thimerosal from solution. Alternatively, the scavenging material may be porous plastic, such as porous polyethylene, imbedded with a cross-linked styrene divinyl benzene which is sulfonated to produce either a positively charged hydrogen form or a negatively charged sodium form. Other scavenging materials useful in the present invention are those relating to chemical affinity techniques, such as immunoassay, active site binding and affinity chromatography. As one particular example, it has been found that a scavenging material comprised of a mixture of "Bio Rex 5" and "AG-4", both Bio Rad products, in a 75 to 25 ratio will almost completely remove .1% sorbic acid from a solution and raise the pH of the solution from 4.0 to 7.0. This is important since sorbic acid is a commonly used preservative in contact lens solutions. In addition, sorbic acid is normally stored at pH = 7.0, where it is not stable. At pH = 4.0, it is very stable but cannot be instilled into the eye. The present invention will therefore allow solution to be stored at low pH and the pH raised to an ocularly acceptable level as the solution is administered. Other preservatives that are not directly charged, such as chlorhexadine, could also be removed by the present invention. For example, a size exclusion mechanism may be utilized for removing certain types of preservative compounds. Overall, the term "scavenging material" as used herein refers to all material which will remove or change the nature of preservatives or other components in a solution exiting the container. From the foregoing description of the invention, it should be seen that the present invention provides the ability to dispense preservative-free solutions from containers housing solutions that are preserved. Whereas the present invention has been described with respect to specific embodiments thereof, it should be understood that various changes and modifications will be suggested to one skilled in the art and it is intended that Bio Rad will remove Thimerosal from solution. Alternatively, the scavenging material may be porous plastic, such as porous polyethylene, imbedded with a cross-linked styrene divinyl benzene which is sulfonated to produce either a positively charged hydrogen form or a negatively charged sodium form. Other scavenging materials useful in the present invention are those relating to chemical affinity techniques, such as immunoassay, active site binding and affinity chromatography. As one particular example, it has been found that a scavenging material comprised of a mature of "Bio Rex 5" and the invention encompass such changes and modifications that will fall within the scope of the appended claims.

Claims: A fitment for scavenging an ophthalmic solution dispensed from the outlet of a container, comprising: a) a body portion having one of its ends capable of being in flow communication with said container outlet, a fitment outlet at its other end and a passageway interconnecting said ends; b) means for engaging said fitment to said container; wherein a scavenging material is provided within said passageway and which is capable of removing a preservative present in the solution as said solution passes from said container outlet to said fitment outlet; and said body comprises a check valve provided in said outlet for controlling the direction of flow of solution from said body. A fitment according to claim 1, characterized in that said scavenging material has a negative charge and said preservative is positively charged. A fitment according to claim 1, characterized in that said scavenging material has a positive charge and said preservative is negatively charged. A fitment according to claim 2, characterized in that said scavenging material is fumed silica and said preservative is a quaternary amonium compound. A fitment according to claim 3, characterized in that said scavenging material is comprised of porous plastic embedded with sulfonated cross-linked styrene divenyl benzene. A fitment according to claim 1, characterized in that said scavenging material selectively scavenges said preservative by a size exclusion mechanism. A fitment according to any one of the preceding claims, characterized in that said means for engaging said fitment to said container are provided on said fitment body, said fitment body being adapted to releasably engage a dispensing head with which a container is provided, said dispensing head having said container outlet therethrough. A dispensing device for dispensing ophthalmic solutions comprising: a) a container body defining a solution retaining chamber therein, said container having a container outlet for dispensing said solution from said solution retaining chamber; b) a dispensing head through which the solution is dispensed; wherein a scavenging material is provided in the passageway of the solution and which is capable of removing a preservative present in the ophthalmic solution as the solution is dispensed from said solution retaining chamber through said outlet; said body comprises a first check valve provided in said outlet for controlling the direction of flow of solution from said body; and a second check valve in said container for regulating the flow of air into said chamber below said scavenging material. A dispensing device according to claim 8, characterized in that said dispensing head is integrally formed on said container body. A dispensing device according to claim 9, characterized in that said scavenging material is provided in the path of said solution through said dispensing head, a first end of said path being in communication with said solution retaining chamber and the outlet of the container being at the second end thereof. A dispensing device according to claim 10, characterized in that said scavenging material is insert-molded into said dispensing head. A dispensing device according to claim 9, characterized in that the dispensing head is the fitment according to any one of claims 1 to 7. A dispensing device according to claim 8, characterized in that said dispensing head is snap fittingly engageable onto said container. A dispensing device according to claim 8, characterized in that said dispensing head is threadingly matable onto said container. A dispensing device according to any one of claims 8,9,13 or 14, characterized in that it comprises a fitment according to any one of claims 1 to 7, which is engageable to said container or to said dispensing head respectively. A dispensing device according to any one of claims 8 to 15, characterized in that the scavenging material is in the form of a porous mass. A dispensing device according to any one of claims 8 to 16, characterized in that said container body is an aerosol can.

Inventors: HEYL BARBARA L, SU KAI C, WHITE JACK C, WINTERTON LYNN C, HEYL, BARBARA L., SU, KAI C., WHITE, JACK C., WINTERTON, LYNN C.
Applicants: CIBA GEIGY AG, NOVARTIS AG
Application year: 1990
Main classification: A61J1
IPC codes: A61J1, A61F9