The present invention relates to the field of devices for dispensing fluid and in particular to those for dispensing fluid to the surface of the eye

Eye hygiene is important as the visual sense is the sense from which we obtain the most information about our environment and yet the eye is a delicate organ Therefore, it is desirable to provide means to wash and irrigate the eye to remove irritants which collect over time. It is particularly useful in environments where the eye could be subject to splashes from corrosive chemicals, swarf or the like where eye washes are used for emergency irrigation of the eye It may also be desirable to apply fluid to the eye for other reasons (e.g. to soothe the eye and/or as a medicament)

Fluids can be difficult to apply to the eye with traditional methods such as eye droppers, which also compromise the sterility of the fluid even when prepared under sterile conditions Eye droppers are messy to use as the head of the user must be facing upwards so the eye socket is approximately horizontal Droppers do not dispense an accurate volume of fluid and yet this is particularly important to ensure correct dosing of active ingredients The user is also deterred from using eye droppers because they contact the eye directly which is both uncomfortable, off-putting to the user and potentially dangerous. Therefore there is a need to develop an alternative means of delivering fluid to the eye Various attempts have been made to solve this problem of delivering fluid to the eye

US 4106673 (Donoghue) discloses a squeezable bottle opening into a cup shaped reservoir suitable for use as an eye bath. The cup has hollow sides which act as a measurement chamber before the washing liquid is introduced into the cup The cup does not provide a good seal to the eye socket to prevent waste of liquid

GB 1460064 (Optrex) discloses an eye bath containing an eye lotion sealed within it by a removable membrane One disadvantage of this bath is that its smooth πm does not provide a good seal with the face when the eye bath is offered up to the eye socket and thus eye lotion can leak from the bath during use

US 3871554 (Huck) discloses a portable eye wash station comprising a collapsible container holding eye lotion (e g of a bellows type construction) which is compressed by a spring automatically when the container is opened to deliver a continuous stream of eye lotion from the neck of the container The disadvantage of such an eye washing apparatus is the rate of discharge of eye lotion is fixed and not in the control of the user and no means is provided for delivery of the lotion to the eye, without leakage

US 4232671 (Crump) discloses a single use flexible eye wash pack comprising eye lotion sealed in a plastic envelope, which contains two sealed holes set approximately one eye width apart On use the membrane seal to the holes is broken, the pack is presented to face and the eye lotion is squeezed out of the holes adjacent to each eye by pressing the pack The disadvantage of such a pack is it can be used only once, it can only be used to wash one eye with messy leakage from the other hole and it can be easily damaged in transit

US 4131115 (Peng) discloses an eye washing device comprising a bottle with separate reservoirs for clean and dirty eye lotion, connected to a cup for offering to the eye The cup also comprising blades to remotely clip and hold open the eyelids The eyelid opening device requires some manual dexterity to use and this would be unsuitable for use by some people It could also be dangerous, it would be easy to accidentally poke the eye if the device was not aligned correctly When abutting the eye socket the cup of this device would not provide a fluid resistant seal to prevent loss of eye lotion

GB 2048074 (Katell) discloses an eye wash bottle having an angled top portion with an integral head for ease of use in applying eye lotion to the eye whilst squeezing the bottle situated vertically in a comfortable position. The frustoconcial head of this device would leak lotion in use when offered up to the eye socket.

US 4363146 (Liautand) discloses a portable eye wash fountain for use in emergencies. On operation, spaced angled heads direct eye lotion upwards fed by gravity from an integral container containing lotion within the device. There is a tray to collect the used lotion. This eye wash fountain is wasteful of lotion much of which may not reach the eye. It is not suitable for washing the eye for other than rapid emergency use, as the eye is not in contact with the lotion very long.

ZA 82/3395 (Wolfson) discloses a device which forms a fluid tight seal between the face of the patient and the device (optionally shaped like a pair of goggles) with an inlet for clean eye wash liquid and an outlet for dirty eye wash liquid. The disadvantage of such a device is that it cannot be used to wash a single eye and requires connection to an external source of eye wash liquid and a container for disposal of the used eye wash liquid. As there is a continuous flow of eye wash liquid through the device, the device is wasteful of liquid.

It can be seen that none of these prior art devices are entirely satisfactory as they all have at least some of the following disadvantages. They are ineffective in use, wasteful of fluid and/or messy to use. A further disadvantage of the prior art is the difficulty of using these devices with one hand whilst holding open the eyelids with the other hand to expose the eye surface to the liquid. Attempts to solve this problem (e.g. Peng) are complicated and potentially dangerous to use particularly for self medication by patients. The prior art devices also require the patient to manipulate the device or move their head to ensure all the eye surface is washed with the fluid. This requires some degree

of practice and manual dexterity for correct use which is a particular disadvantage for some patients, for example the infirm. Furthermore, moving the head may result in leakage of fluid from the eye bath in use.

It would be desirable to provide a device which can deliver fluid directly to the eye with the face of the user in an upright position, which can dispense accurately small volumes of fluid to the eye with little or no leakage or wastage, in which the device does not contact the eye surface. The device should also be easy to use especially with one hand and particularly by less dextrous users such as the elderly or the infirm. Preferably the device should contain the fluid so that there is no messy filling of the device prior to use, which has the added advantage that the device may be portable if required and may be kept by the user in a bag or pocket prior to use.

Therefore it is an object of the present invention to overcome some or all of the aforementioned disadvantages of the prior art devices and to produce a device which has some or all of the desirable features described herein. The applicant has developed a device which produces a gentle cloud of fluid around the eye and has some or all of the preceding advantages and overcomes some or all of the problems associated with the prior art.

Therefore broadly in accordance with the present invention there is provided a device for applying fluid topically to a patient, the device comprising a housing with an orifice, the housing mounting a plunger assembly for sliding movement between a first position and a second priming position and a biasing means acting on the lunger assembly to urge the plunger assembly towards the first position, a releasable locating means to hold the plunger assembly in the priming position against the action of the biasing means, and a storage chamber storing the fluid, the storage chamber being connected via a first valve means to deliver fluid to a charge chamber and the charge chamber being connected via a second valve means to deliver fluid to atomising means, the

atomising means being connected to deliver fluid to the housing orifice; the construction and arrangement being such that to prime the device the plunger assembly is moved from the first position to the priming position to cause a predetermined volume of the fluid to enter the charge chamber through the first valve and air to enter the housing through the orifice, the plunger assembly being held in the priming position against the biasing means by the locating means; and such that to dispense fluid to the patient, when the device is placed with the orifice adjacent to the site of application, the locating means is released to allow the biasing means to move the plunger assembly from the primed position to the first position which causes the fluid to leave the charge chamber through the second valve means, enter the atomising means where the fluid is mixed with air and be expelled from the orifice.

Preferably the device is suitable for applying fluid to the surface of the eye of the patient, the fluid is a sterile fluid suitable for application to the surface of the eye of the patient and the device is capable of expelling the fluid from the orifice as a mist. Although the dispensers of the present invention have primary utility in the delivery of sterile fluid to the surface of an eye, they could be used (with all the advantages described herein) to deliver any suitable fluid topically to any suitable site on a patient in need thereof and in such a case the fluid is preferably of a type (e.g. a sterile fluid) which it would be undesirable for the patient to contact before application.

Optionally the device comprises a removable cap which fits over the orifice in the housing, advantageously held there by friction. Preferably the cap comprises a means for keeping the orifice and that part of the housing enclosed by the cap sterile, to prevent contamination of the sterile fluid before it contacts the eye surface. More preferably the cap comprises a source of anti-microbial agent, most preferably an absorbent material (e.g. a suitable non-woven material and/or Porex ®) impregnated with a suitable anti-microbial agent, such as a bactericide, for example benzalkonium chloride.

Preferably that part of the housing adjacent the orifice and optionally enclosed by the cap is shaped to fit within the eye socket, to provide a substantially fluid resistant seal when that part of the device is offered to the eye socket.

Preferably the biasing means is a helical compression spring, conveniently mounted concentrically about the piston or any mechanical equivalent thereof. The biasing means may be any other mechanical equivalent which will perform the same function.

Preferably the locating means is positioned on the outside of the housing, more preferably is operable with one hand, most preferably comprises a pivotabiy mounted latch, moveable between a piston locating position and a position which allows the piston to slide freely.

The device can optionally be further packaged in a sterile sealed pack if it is designed for throwaway single use, although it is an advantage of the present invention that such devices can dispense repeated multiple doses of sterile fluid to the eye.

A device of the present invention can deliver at a low velocity a pre-primed spray formed from drops of typically 10 μm to 15 μm in diameter, without contact between the eye surface and the device and in a non-aggressive delivery. Fluid is absorbed indirectly and gently onto the eye surface as a mist not as a directed jet. The device does not require the user to have a bare face or wear waterproof make-up as spillage, leakage and wastage is substantially eliminated or reduced. The priming stage is effected by extending of a plunger / piston which can be done away from the face which makes subsequent use an easy one handed operation. The device housing may be moulded into a suitable shape to aid one handed operation.

Release of an external button latch on the housing can cause automatic slow release of sterile eye mist. The delivery speed can be controlled by the strength of the biasing means (e.g. spring) and a biasing force of up to 4 kg weight force would be acceptable for a typical user and this would create a pressure change of about 4 bar within the charge chamber when the piston is released. A fluid delivery time of ideally about 2 to 3 seconds would remove any anxious wait by the users and yet ensure that the mist reached the eye surface regardless of any involuntary blinking. The dose is controlled accurately, and an indicator of the total dose dispensed can easily be incorporated into the device. For example a counting means may be provided which is linked to release of the latch and/or movement of the plunger and calibrated according to the volume of the charge chamber.

The preferably sterile fluid that may be dispensed by dispensers according to the present invention may be in any dosage form (for example liquid, gaseous and/or free flowing powder) that is suitable for use in the dispensers described herein and preferably suitable for application to the eye surface. Optionally the dispenser of the present invention may administer the fluid in the form of: drops; fine powders and/or granules; a spray; a mist; and/or an aerosol. The fluid is preferably substantially free of ocular irritants and may comprise any suitable elixir, lotion, solution, syrup and/or suspension. The fluid may be sterilised by any suitable method, for example chemically (e.g. by use of suitable preservatives) and/or by irradiation of the fluid during manufacture of the dispensers of the present invention.

The fluid is preferably liquid, more preferably a water miscible liquid (for example an aqueous solution) and may further comprise one or more of the following (and/or mixtures thereof) in amounts which are not ocular irritants and which are acceptable for application to the eye surface: agents which vary osmotic pressure (for example salts); pH adjusting agents (for example a borate phosphate salt buffer) that maintain the pH of the fluid within a particular pH

range (for example 5 to 8); preservatives (for example parabens and/or phenoxyethanol); and dilute aqueous solutions of salts such as sodium chloride which are isotonic with lachrymal secretions.

Sterile fluid may be applied to the eye surface by the dispensers described herein to wash, soothe and/or irrigate the eye. Thus the sterile fluid may comprise suitable eye cleansing agents, bathing agents, wetting agents and/or soothing agents (such as the liquid composition available under the trade mark Optrex ®).

The sterile fluid may also be applied directly to the eye surface for therapeutic reasons to treat (by therapy or prophylaxis) suitable diseases and/or disorders whether directly of the eye (e.g. glaucoma) or systemically. Thus the fluid may also comprise (preferably in additional to the ingredients described above) one or more pharmaceutically active ingredients which have a local ocular and/or general systemic effect. Such ingredients may be available over the counter (OTC) or only with a prescription from a medical practitioner (POM). Pharmaceutical compositions for use with the dispensers of the present invention (such as ophthalmic compositions) may be available in known pharmaceutical forms for ocular administration (for example a water-miscible, fluid composition).

The precise amount of any pharmaceutically active ingredient administered to the eye surface in a sterile fluid using the device described herein will depend on a number of factors. Such factors may comprise any or all of the following: the specific compound administered and/or the intended use; the particular clinical condition being treated (if any) and/or its severity; and the age, body mass and/or past clinical history of the patient using the device. In any event the amount of pharmaceutically active ingredients administered to the eye lies within the sound discretion of the person administering and/or supervising use

of these devices (if any) such as a pharmacist, medical practitioner [for example nurse and/or physician] and/or veterinary.

Nevertheless a suitable daily dose of a pharmaceutically active ingredient for ocular administration to an patient is generally from about 0.01 mg/day per kg of the patient's body mass to about 100 mg/kg/day given in a single dose and/or in divided doses at one or more times during the day. The total dose of the pharmaceutically active ingredients administered per day may be generally from about 0.1 mg to about 5000 mg. Fluids suitable for ocular delivery may comprise from about 0.1 ng/ml to about 100 mg/ml of pharmaceutically active ingredients. If the pharmaceutically active ingredients comprise a salt, the amounts indicated above refer to the total mass of the corresponding pharmaceutically active ingredients that are other than a salt. Typically a device according to the present invention might have a storage chamber of about 7.5 ml in volume and dispense 30 doses of fluid each of volume 250 μl.

A non-limiting specific embodiment of the present invention will now be described with reference to the following example and the drawings in which: Figure 1 is a perspective view of the device with the cap removed; Figure 2 is a longitudinal cross section (along the longest axis of the device shown in Figure 1) of the interior of the device before use with a cap attached;

Figure 3 is the same view of the device as shown in Figure 2, with the cap removed and the device in the primed position ready for use; and Figure 4 is the same view of the device as shown in Figures 2 and 3, with the cap removed and the device in a position during which fluid is delivered to the eye.

With reference to Figures 1 and 2, an embodiment of the invention comprises a dispenser of liquid for cleaning and/or soothing the eye (such as that available under the trade mark Optrex ®). The dispenser comprises an outer case body

(1 ) made from polypropylene to which is attached by fπctional fit a removable propylene cap (3) inside of which there is fixed a wad (5) of Porex ® impregnated with benzalkonium chloride bacteπcide Mounted on the outside of the case (1) is an polypropylene actuation button (7) pivoted about fulcrum (9) The button is attached to latch (11 ) inside the case (1) At the end of the case (1 ) covered by the cap (3) when the device is not being used, there is an open, propylene, locating web (13) The outer case (1 ) around the web (13) can be shaped to provide a seal with an eye socket, to prevent or reduce leakage of Optrex ® when the dispenser is used

The other end of the case (1), directly opposite the web (13) is formed by a propylene base wall (15) A polypropylene plunger handle (17) protrudes from the base wall (15), the handle (17) forming part of a plunger assembly (19) which is slidable along the long axis of the case (1 ) within a hole (21) in the base wall (15)

Inside the case (1) the plunger assembly (19) comprises a polypropylene annular flange (23) which abuts the cylindrical inner wall (25) of the case (1) to provide a liquid-tight seal within the case The plunger assembly (19) also comprises a polypropylene hollow tubular plunger body (26) which connects the flange (23) to the handle (17) The plunger assembly (21) is slidable within the inner wall (25) in a region of constant bore Between the flange (23) and the base wall (15) a stainless steel helical compression spring (27) is mounted concentrically around the plunger body (26) so when the flange (23) abuts the web (13), at the position of maximum extension of the spring (27), it remains under partial compression

Inside the plunger body (26) there is a storage chamber, or reservoir (29), of volume 7 5 ml containing 30 doses of Optrex ® liquid The end of the reservoir (29) away from the web (13) comprises a movable low density polyethylene (LDPE) wall (30) slidable within the reservoir (29) whilst maintaining a liquid

seal to allow the volume of the reservoir (29) to decrease as the Optrex ® is dispensed. The other end of the reservoir (29) is a tube (31) of narrower bore which ends in a seal (33) made from silicon rubber or polyethylene pseudo-elastomer. Concentrically mounted around the narrow tube (31) and within the plunger body (26) there is a charge chamber (35) defined by a polycarbonate outer shell (37) within the plunger body (26) and a polycarbonate inner shell (39) within the outer shell (37). The seal (33) prevents the Optrex ® from flowing between the narrow tube (31) and the inner shell (39). In the seal (33) there is a narrow orifice (41) which acts as a valve, so Optrex ® can flow only from the reservoir (29) to the charge chamber (35). The outer shell (37) is located within the web (13). Located between the inner shell (39) and outer shell (37) there is a polycarbonate disc (43) with a tiny aperture (45) of 0.1 mm diameter through which the Optrex ® is dispensed. The aperture (45) helps both to atomise the Optrex ® and acts as a valve to allow the Optrex ® to flow in one direction only, from the charge chamber (35) through the open web (13) to the exterior of the device. Around the aperture (45) there is a conical shaped depression (47) formed around a gap in the outer shell (37) which also helps the Optrex ® leaving the aperture (45) to form tiny droplets. The depression (47) together with inwardly curved inner walls (49) at this end of the case (1), near to aperture (45), form a swirl chamber (51) in which the Optrex ® droplets and air are mixed to form a mist.

The device must be primed before Optrex ® can be dispensed. The cap (3) is removed, the swirl chamber (51), the aperture (45) and the web (13) being sterile due to the bactericide in wad (5). The device is primed by pulling handle (17) until the plunger assembly (19) can move no further being held by latch (11 ) and this is the position shown in Figure 3. The disc (43) seals the charge chamber (35) against air entering the chamber (35) which creates a pressure difference between the reservoir (29) and the charge chamber (35). Thus Optrex ® in the reservoir (29) flows through the narrow tube (31) via orifice (41)

into the charge chamber (35) and the reservoir wall (30) moves to reduce the volume of the reservoir (29) and equalise the pressure. At the same time movement of the plunger assembly (19) moves the flange (23) further inside the case (1) and thus air is drawn inside the case through the open web (13) as indicted by arrows 'A' in Figure 3. In this primed position the spring (27) is further compressed and the plunger assembly (19) is held in place by latch (11 ). A 250 μl volume of liquid Optrex ® is held in charge chamber (35), the volume of each dose being pre-determined by the dimensions of the device. The device can dispense 30 such doses of Optrex ® before the reservoir (29) must be refilled or the device discarded.

After priming the device can deliver Optrex ® to the eye. The device is placed with the outer case (1) adjacent the web (13) abutting the eye socket of the eye to be treated. The button (7) is depressed which causes it to pivot about its fulcrum (9) and move the latch (11) to release the plunger assembly (19). The plunger assembly (19) then moves toward the web (13) under the force of spring (27). This is the position of the device as shown in Figure 4, with the plunger assembly (19) travelling from the primed position shown in Figure 3 to the rest position shown in Figure 2. Corresponding movement of the seal (33) within the charge chamber (35) forces the Optrex ® dose therein through the aperture (45) in disc (43) and into the swirl chamber (51). Simultaneously the flange (23) forces air out of the device into the swirl chamber (51) as shown by arrows 'B' in Figure 4. The air mixes with Optrex ® droplets formed in the swirl chamber (51 ) to create a mist of Optrex ® which is vented into the region adjacent the eye and is absorbed by the eye surface.

This method of delivering Optrex ® is gentle to the eye surface and is easier to use by the lay-patient. The dispenser delivers an accurate predetermined dose of sterile Optrex ® in a controlled manner with less leakage or wastage than prior art devices or methods.