WO2012085937A1

WO2012085937A1 - Device suitable for dispensing liquid medicament

Info

Publication number: WO2012085937A1
Application number: PCT/IN2011/000872
Authority: WO
Inventors: Prashant Kane; Satish Madhukar Gokhale; Nachiket Gole
Original assignee: Sun Pharma Advanced Research Company Ltd.
Priority date: 2010-12-21
Filing date: 2011-12-20
Publication date: 2012-06-28
Also published as: TW201231117A; AR084458A1

Abstract

The present invention describes a device suitable for dispensing multiple doses of a liquid medicament, the device comprising a) a container having a liquid medicament therein, comprising at least one collapsible wall (3) b) a rotating plunger (7) connected to a push button (8) and c) locking means wherein upon pressing the push button (8), the rotating plunger (7) rotates and traverses from the first position to a traversed position causing preset compression of the collapsible wall of the container (3) to dispense a preset volume of the liquid medicament, and wherein the rotating plunger (7) is locked from returning to the first position by the locking means, thereby preventing air from entering back into the container to maintain a sterile environment within the container (3).

Description

DEVICE SUITABLE FOR DISPENSING LIQUID MEDICAMENT

FIELD OF THE INVENTION

The present invention relates a device suitable for dispensing multiple doses of a liquid medicament while maintaining the sterility of the container having the liquid medicament therein.

BACKGROUND OF THE INVENTION

For years, the primary method of medically treating eye disorders has been via topical administration of various liquid medications. Typically, dispensers have varied sizes and shapes of the drops being dispensed aid there is no reproducible standard drop size that is governed by the dropper (dispenser) tip. Further, the most common problem that the typical patient experiences when attempting to use a topical preparation like for example an eye drop, is the issue of the waste. When a drop is introduced into the eye, the average inferior cul-de-sac only holds^' one-quarter to one-half of a standard drop. The remainder is either washed out down the cheek, Or drained by the lachrymal system. Apart from this problem of non uniform size of the drop that gets dispensed, wastage of the medicament, there are also problems associated with the use of preservative in the liquid medicament. For example, 'Benzalkonium chloride' a known preservative is reported to cause damage to the cornea during their use in chronic treatment [Cha et al in Clin Experiment Ophthalmol. 2004 Apr; 32(2): 180-4]. It is well known by now that preservatives have been linked to side effects and allergic reactions and therefore, one could say that there is an unmet need of an ideal device that can prevent the wastage problem as mentioned above as well as can provide feasibility to include a preservative free medicament wherein the design of the device maintains the sterility of the medicament.

Reviewing the prior art, one can come across numerous efforts being made to design a device which is ideal for the delivery of liquid medicament for topical administration. For example, European Patent Application EP 1779832 describes a squeeze container comprising a container body for containing a liquid, and a neck that leads to an opening end of the container body, wherein the container body has bellows that contracts and expands in a direction generally perpendicular to the direction of the delivery of the liquid is discharged through the neck, the bellows have a plurality of pleated portions disposed in the direction of delivery, Each of the pleated portions is disposed at intervals from each other in the direction of contraction, a width of the pleated portion at a convex edge in a direction perpendicular to the direction of contraction is made to decrease from a middle to both ends in the direction of contraction, and a width of the pleated portion at a concave edge in the direction perpendicular to the direction of contraction is made to decrease from the middle to the both ends in the direction of contraction. United States Patent Number US 6,336,571 describes a device for packaging a liquid that is to be dispensed drop by drop, comprising a flexible-walled flask (1) that can be deformed manually to gradually decrease its internal volume towards a rigid neck (5) in which is leaktightly mounted a dispensing head (2) ending in a conduit (41) for expelling the liquid out of the flask, characterized in that this device comprises a microporous pad (6) inserted in a body (3) of the said head across the cross-sectional area for the passage of the liquid between said flask (1) and said conduit (41) upstream of a liquid-distribution chamber (31) of large cross-sectional area formed in said body (3) between a downstream surface (63) of said pad (6) and said expulsion conduit (41), said pad (6) being made of a material that is inert with respect to the liquid and capable of creating a head loss which regulates the flow of liquid driven through it by the pressure generated in the flask (1) upon each action to reduce its volume and said distribution chamber (31) having a large enough volume to accommodate the liquid which has passed through said pad (6), said flask (1) being bounded by a wall of cylindrical overall shape in the form of a longitudinally deformable bellows (12) ending in a rigid transverse bottom (13) and being isolated from any possibility of air entering to replace the expelled liquid.

Many efforts are being done to design a simpler device that can hold and dispense a liquid medicament for multi-dose administration. For instance, recently granted, United States Patent Number US 7,338,228 disclose an applicator device for a liquid product contained in a reservoir container, said device comprising a lid for closing the opening of said container; at least one migration canal through said lid for the capillary migration of said liquid product to a wettable surface brought into contact therewith outside said container, a downstream end of said capillary migration canal opening to the outside of said lid; a withdrawal tube for withdrawing said liquid product from said container, in which an upstream end of said migration canal opens and that is constructed so as to retain a determined dose of liquid product withdrawn from said container against the action of gravity through a capillary effect; and a removable cap with a layer of material that is absorbent for the liquid on the outside of said lid but unable to absorb the liquid inside the at least one migration canal and the withdrawal tube. Another United States Patent Application US201001452871 discloses an assembly for holding and dispensing a medical liquid, of the type comprising:

a vessel (4) for containing the liquid, the vessel (4) having a neck (14); a dispensing dropper end fitting (6) disposed at the end of the neck (14), the end fitting (6) and the vessel (4) allowing the liquid to be dispensed drop by drop by squeezing the vessel (4) between the fingers of one hand; and a cap (8) for closing the vessel (4), provided to be screwed onto the neck (14); characterized in that the cap (8) and the neck (14) have safety means , preventing the cap (8) from being unscrewed only by applying an unscrewing torque, and allowing the cap (8) to be unscrewed when an additional action is applied together with the torque for unscrewing the cap (8).

Thus, it is apparent that in-spite of several attempts, still there remains a need to create an ergonomic multiple dose device that can hold and dispense a sterile liquid medicament, while maintaining sterility of the medicament. Therefore, a device that can avoid the use of preservative, which is otherwise required for maintaining the sterility of the liquid medicament, as well as which can dispense a preset volume of the liquid medicament, is always desirable. The device of the present invention achieves these objectives.

SUMMARY OF THE INVENTION

The present invention describes a device suitable for dispensing multiple doses of a liquid medicament, the device comprising a) a container having a liquid medicament therein, comprising at least one collapsible wall (3)

b) a rotating plunger (7) connected to a push button (8) and

c) locking means

wherein upon pressing the push button (8), the rotating plunger (7) rotates and traverses from the first position to a traversed position causing preset compression of the collapsible wall of the container (3) to dispense a preset volume of the liquid medicament, and wherein the rotating plunger (7) is locked from returning to the first position by the locking means, thereby preventing air from entering back into the container to maintain a sterile environment within the container (3).

DETAILED DESCRIPTION OF FIGURES

Figure 01 : Exploded isometric view

1 : (a) External Cap (b) Container Cap

2 : Nozzle

3 : Container with collapsible wall

4 : External Cover Left Half

5 : External Cover Right Half

6 : Level Indicator

7 : Rotating Plunger

8 : Push Button

9 : Stationary Screw

10: Rubber Ring

Figure 02: Complete assembly front view

Figure 03 : Complete assembly side view

Figure 04: Complete assembly isometric view

Figure 05: Complete assembly top view

Figure 06: Complete assembly section view

1 : (a) External Cap (b) Container Cap

2 : Nozzle

3 : Container with collapsible wall 4 : External Cover Left Half 5 : External Cover Right Half

6 : Level Indicator

7 : Rotating Plunger

8 : Push Button

9 : Stationery Screw

10 : Rubber Ring

Figure 07: External cover (right half): front view Figure 08: External cover (right half): side view

5 : External Cover Right half

10 : Rubber Ring

39 : Cut-outs

Figure 09: External cover (right half): isometric view-1

5 : External Cover Right Half

10 : Rubber Ring

11 : Half Circular Rib

12 : Half Circular Cut-out

17 : Semi-elliptical slot

18 : Ratchet arm

21 : Ribs

36 : Top End of External Cover Figure 10: External cover (right half): isometric view-2

5 : External Cover Right Half 15 : Guide Rails

16 : Stopper Surface

20 : Circular Shape

19 : Non circular shape

41 : Cut outs

Figure 11 : External cover (left half): front view Figure 12: External cover (left half): side view

4 : External Cover left half 10 : Rubber Ring

38 : Cut outs

Figure 13: External cover (left half): isometric view

4 : External Cover Left Half

10 : Rubber Ring

. 11 : Half Circular Rib

12 : Half Circular Cut out

40 : Cut outs

Figure 14: Nozzle: front view

Figure 15: Nozzle: Top view

Figure 16: Nozzle: isometric view

Figure 17: Push button: front view

Figure 18: Push button: side view

43 : Tapering tip that fits in the cavity between the two consecutive external gear teeth of the rotating plunger (7)

Figure 19: Push button: isometric view

8 : Push Button

14 : Slot

29 : Flexing Arm

42 : Surface

43: Tapering tip that fits in the cavity between the two consecutive external gear teeth of the rotating plunger (7)

Figure 20: Stationary screw: side view

Figure 21 : Stationary screw: top view

Figure 22: Stationary screw: isometric view

30 : External Screw Threads

31 : Spring

32 : Discs

33 : Discs

34 : Surface

Figure 23: Rotating plunger: side view 26: Flat Surface

27: Spherical Surface

Figure 24: Rotating plunger: top view

Figure 25: Rotating plunger: isometric view

24 : External Gear Teeth

25 : Internal Screw Threads

Figure 26: Level indicator: front view

Figure 27: Level indicator: top view

Figure 28: Level indicator: isometric view

Figure 29: Integrated bellow container: front view

13 : Slot

23 : Bellow Shaped Flexible Portion

28 : Container Surface

37 : Rigid Neck Portion

Figure 30: Integrated bellow container: top view

Figure 31 : Integrated bellow container: isometric view

Figure 32: External cap: front view

Figure 33: External cap: top view

Figure 34: External cap: isometric view

Figure 35: Rubber ring: front view

Figure 36: Rubber ring: top view

Figure 37: Rubber ring: isometric view

DETAILED DESCRIPTION OF THE DRAWINGS

Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like refererice numerals designate corresponding parts or features of parts throughout the several views. Cap assembly (1): Cap assembly 1 (as shown in figures 32, 33, and 34) consists of external cap 1-a placed on top of a container cap 1-b. It is designed in such a way that it is easy for the user to remove the cap. The external cap 1-a may be fitted on to the container cap 1-b or both the caps may be joined together by means known in the art, such as for example by heat sealing or by welding together or the like. Alternatively a single cap that covers the Nozzle is used. The cap(s) primarily functions to protect the nozzle and the container contents from exposure to the outside environment. Another function of the cap(s) of the invention is to facilitate breaking of the seal of the container by generating a torque by the twisting action of the cap before the first administration of the medicament in order to make the container ready for subsequent use by the user. The shape of the External cap 1-a (as shown in Figures 32, 33 and 34) provides an ergonomic grip of the cap making the task of twisting the cap to generate a torque sufficient to break the seal of the container and also the removal of the cap before each administration of the medicament, much easier.

Nozzle (2): The nozzle 2 (as shown in figures 14, 15, 16) is designed such that, it, in combination with the bellow shaped flexible portion (23) on the collapsible walls of the container (3), rotating plunger (7), push button (8) and stationary screw (9), dispenses a single drop of microliter amounts of the liquid. The Nozzle 2 of the invention functions to produce and dispense microlitre sized drop of the liquid to be dispensed. The nozzle tip at its dispensing end has an internal diameter and an outer diameter and the tip is connected to an aperture inside the nozzle (2) by a capillary tapering from the dispensing tip to the aperture in the nozzle (2). The diameters of the aperture and the nozzle tip in conjugation with the surface tension of the liquid to be administered lead to the formation of a microliter sized drop. The diameters of the aperture and the nozzle tip can be varied to produce a fixed sized microlitre volume drop for liquids of different surface tensions. The nozzle (2) may be made from a hydrophobic material or it may be coated with a hydrophobic substance in order to reduce the wetting of the tip and avoid pooling of the liquid to form a larger drop. Container having collapsible wall (3): Container having collapsible wall (3) (as shown in figures 29, 30, 31) of the invention is integration of rigid neck portion (37) and bellow flexible shaped portion (23) on the walls separated by the slot (13). Shape of portion (23) can be different than bellow as long as it allows collapsing of the container (3) without considerable efforts felt by the user. The nozzle (2) may be fitted on to the container (3) or both may be joined together by means known in the art, such as for example by interference fit or heat sealing or by welding together or may be made integral or the like.

External, cover - left half (4) and External cover - right half (5): External covers (4) and (5) (as shown in figures 7, 8, 9, 10, 1 1, 12, 13) surrounding the Integrated bellow container (3), rotating plunger (7) and stationary screw (9) are present in the device and are generally made of a rigid material and have a semi-elliptical slot (10) each for housing the push button (8). External covers (4) and (5) also comprise another semi- elliptical slot (17) each for fitting level indicator (6).

The push button (8) is provided with a slot (14) on both sides, which guide the push button (8) along guide rails (15) each provided in the external covers (4) and (5). At the end of the guide rails (15) there is a stopper surface (16) each provided in External covers (4) and (5).

A half circular rib (11) each with half circular cut-out (12) each is provided in the wall of external covers (4) and (5) above the slot (18) to mattingly fit the slot (13) in the integrated bellow container (3.) The rib (11) each of the external covers (4) and (5) and the slot (13) in the integrated bellow container (3) are useful to locate and align integrated bellow container (3) precisely in the External covers (4) and (5) and lock the integrated bellow container (3) in place so as to avoid un-required movement of the integrated bellow container (3) in the External covers (4) and (5).

External cover - right half (5) is provided with a spring like ratchet arm (18) to restrict the rotary movement of rotating plunger (7) in one direction only. This ensures that the collapsible wall of the container (3) will not expand to allow air entry inside it. Combination of non-circular shape (19) (may be semi-hexagon), circular shape (20) and ribs (21) each at one end of the external covers (4) and (5) holds stationary screw (9) firmly in position. External covers (4) and (5) have been provided with elliptical shaped depressions (22) each on outer surface to guide the user to hold the device in a correct manner. Both the external covers (4) and (5) may be fixed together by methods like snapping, screwing or like that. Cut-outs (38) and (39) provided in external covers (4) and (5) acts as window to check tamperproof ness of container cap 1-b. Cut-outs (40), (41) provided in external covers (4) and (5) allows user to keep watch on the nozzle tip damage, cleanliness etc.

Level indicator (6): Level indicator (6) (as shown in figures 26, 27, 28) fitted onto the external cover (4) and (5) is a transparent component. The level indicator is a window to see end of life function. At the end of life stage, a user will see fully red flag to indicate the medicament is completely consumed.

Rotating plunger (7): Rotating plunger 7 (as shown in figures 23, 24, and 25) is combination of external gear teeth (24) and internal screw threads (25). The profiles of external gear teeth (24) and internal screw threads (25) are designed such that each stroke of push button (8) results in dispensing a drop of predetermined size. Another combination of flat surface (26) and spherical surface (27) at one end of the Rotating plunger (7) is in contact with surface (28) of the integrated bellow container (3). The flat surface (26) pushes container surface (28) axially to squeeze the Container with a collapsible wall (3) to dispense a drop of predetermined size. The spherical surface (27) grips container surface (28) thus restricting any lateral movement of the container (3). Ultimately rotating movement the rotating plunger (7) controls the upward movement of the container (3).

Push button (8): Push button (8) (as shown in figures 17, 18, and 19) is designed to rotate the rotating plunger (7) when pressed in. When the push button (8) is pressed, while push button (8) slides along guide rails (15) each provided in the External covers (4) and (5) a flexing arm (29) with a tapering tip (43) that fits into the cavity between the consecutive external gear teeth (24) of the rotating plunger (7) thus causing rotary movement of the rotating plunger (7). The push button (8) movement is restricted when surface (42) of push button (8) touches stopper surface (16) each provided in external covers (4) and (5). Piece having threads such as stationary screw (9): Portion contained within discs (32), (33) of stationary screw (9) (as shown in figures 20, 21, 22) is held firmly within non- circular shape (19) (may be semi -hexagon), circular shape (20) and ribs (21) each provided on external covers (4) and (5). The external screw threads (30) of stationary screw (9) hold internal screw threads (25) of rotating plunger (7). Surface (34) of spring (31) integrated with the stationary screw (9) pushes back push button (8) when the push button (8) is released by the user.

Rubber ring (10): Rubber ring 10 (as shown in figures 35, 36, and 37) is rubber component located at top ends (35), (36) of external covers (4) and (5) respectively.

DETAILED DESCRIPTION OF THE INVENTION

A] The present invention describes a device suitable for dispensing multiple doses of a liquid medicament, the device comprising

a) a container having a liquid medicament therein, comprising at least one collapsible wall (3)

b) a rotating plunger (7) connected to a push button (8) and

c) locking means

B] A device as described in A wherein the rotating plunger (7) comprises external gear teeth (24), internal screw threads (25) and a combination of flat surface (26) and spherical surface (27) at one end. C] A device as described in B wherein the flat surface (26) and spherical surface (27) of the rotating plunger (7) on which the surface (28) of the container with a collapsible wall (3) rests.

D] A device as described in A wherein the rotating plunger (7) is mounted on a threaded piece (9) having external threads (30).

E] A device as described in D wherein the rotating plunger (7) is mounted on a threaded piece of the stationary screw (9) having external screw threads (30).

F] A device as described in E wherein the external screw threads (30) of the stationary screw hold the internal screw threads (25) of the rotating plunger (7).

G] A device as described in A wherein the push button (8) is connected to the rotating plunger (7) by means of a flexing arm (29) having tapering tip (43) wherein when the push button (8) is pressed, it slides along the guide rail (15) each provided in the external cover (4) and (5) the flexing arm (29) having the tapering tip (43) which fits into the consecutive external gear teeth (24) of the rotating plunger (7) and pushes the external gear teeth (24) of the rotating plunger (7), causing the rotary movement of the rotating■ plunger (7).

H] A device as described in A wherein the volume of the liquid medicament that is dispensed is dependent on the distance traversed by the rotating plunger (7).

I] A device as described in A wherein the locking means includes a ratchet arm (18) which is part of the stationary external cover (5).

J] A device as described in H wherein the ratchet arm (18) locks with the external gear teeth (24) of the rotating plunger (7) to restrict the rotary movement of the rotating plunger (7) in a single direction.

K] A device as described in A wherein the collapsible walls are in the form of bellows or ribs or tubes or balloon.

L] A device as described in A wherein the preset volume of the liquid medicament is ^' about 50 microlitres.

Container having collapsible wall (3) of the present invention can be used for administration of cosmetic or medicament liquids to the user. The container of the invention dispenses microliter amounts of a liquid in the form of a drop. The device of the invention is used for delivery of medicaments to the body cavities such as eyes, ears, nose and the like of the user. In a particularly preferred embodiment of the present invention, the device of the invention is used to administer medicament to the eyes of the patient. Typically the device is used to deliver ophthalmic medicaments to the user. Due to the unique construction of the device, the medicament does not require the addition of a compound that acts as a preservative. Due to the restriction of the movement, the outside air cannot enter inside the container upon squeezing of the container for dispensing of the liquid medicament. Therefore, the device of the present invention can also be termed as 'preservative free liquid medicament' delivery device.

According to the present invention, the device suitable for dispensing multiple doses of a liquid medicament, the device comprises

b) a rotating plunger (7) connected to a push button (8) and

c) locking means

wherein upon pressing the push button (8), the rotating plunger (7) rotates and traverses from the first position to a traversed position causing preset compression of the collapsible wall of the container (3) to dispense a preset volume of the liquid medicament, and wherein the rotating plunger (7) is locked from returning to the first position by the locking means thereby preventing air from entering back into the container to maintain a sterile environment within the container.

In one particular embodiment, the rotating plunger (7) is rotated by means of a push button (8) which comprises a flexing arm (29) having a tapering tip (43) that is designed to fit in the cavity between the two consecutive external gear teeth (24) of the rotating plunger (7).

Particularly, in one embodiment the rotating plunger (7) is mounted on a threaded piece such as stationary screw (9) having external screw threads (30). The rotating plunger (7) comprises external gear teeth (24), internal screw threads (25) and a combination of flat surface (26) and spherical surface (27) at one end. According to the present invention, the external screw threads (30) of the stationary screw (9) hold the internal screw threads (25) of the rotating plunger (7). It is the distance traversed by the rotating plunger (7) that governs the volume of the liquid medicament that is dispensed. Ultimately rotating movement the rotating plunger (7) controls the upward movement of the container (3).

The device of the present invention in one of the embodiment includes a spring as the locking mean. The spring can be in the form of an arm that is housed on an external cover to restrict the rotary movement of the rotating plunger (7) in a single direction.

In one embodiment, the device of the present invention can be used for delivery of the liquid medicament by first holding the device and rotating the cap (1) to open. The device should be held such that push button (8) is facing the user and thumb is placed on push button (8) and fingers are placed against elliptical depressions (22). The rubber ring (10) is to be placed on lower eye lid and should be pulled down. The head needs to be tilted and the push button (8) needs to be pressed with thumb. After dispensing the required dosage of medicament in each eye, the device is to be taken away from the eye and the cap 1 is to be put back in its original position and rotated to close. In one embodiment of the present invention, the container having collapsible wall (3) (as shown in figures 29, 30, 31) is integration of rigid neck portion (37) and bellow shaped flexible portion (23) on the walls separated by the slot (13). In certain other embodiments, the container having collapsible wall (3) may be in the form of the bellows, ribs, tubes or balloon. In all these embodiments it is important that the shape of the container allows collapsing of the container (3) without considerable efforts felt by the user. The nozzle (2) may be fitted on to the container (3) or both may be joined together by means known in the art, such as for example by interference fit or heat sealing or by welding together or may be made integral or the like. In one embodiment of the present invention, the device comprising

i) a container is in the form of a bottle having a liquid medicament therein, comprising at least one collapsible wall in the form of bellow (3)

ii) a rotating plunger (7) connected to a push button (8)

iii) locking means in the form of a spring like ratchet arm.

wherein upon pressing the push button (8), the rotating plunger (7) rotates and traverses from the first position to a traversed position causing preset compression of the collapsible wall of the container (3) to dispense a preset volume of the liquid medicament, and wherein the rotating plunger (7) is locked from returning to the first position by the locking means thereby preventing air from entering back into the container to maintain a sterile environment within the container (3).

The material that is used for the container may be a deformable material such as low density polyethylene, PET, PP and the like.

The device according to the present invention includes a 'locking means' which may be of the following types such as free wheel mechanism (essentially similar to ratchet mechanism, but the mechanical elements are different, the effect being the same) or mechanical uni-directional frictional resistance or by use of hydraulic or pneumatic means with a non-return valve to restrict the backward movement or like a drop feed mechanism using feed dogs like in a sewing mechanism for advancing the cloth being sewed. This is done by guiding the movement of the flexing (spring like) arm (29) in the push button (8) in such a manner that it is contact with the external gear teeth (24) of the rotating plunger (7) during forward stroke of the push button (8) and free from contact during the reverse stroke of the push button (8). Here the arm acts as a 'feed dog' and need not be spring like. However, it may be understood that the locking means are not limited to the above listed types and can be of any type that fits as per the design of the device so that the rotating plunger (7) is restricted from returning to its original position, after the driving arm forces it to move in the direction of the collapsible wall of the container (3). The rotating plunger (7) comprises external gear teeth (24), internal screw threads (25) and a combination of flat surface (26) and spherical surface (27) at one end. It is located on a threaded piece such as a stationary screw (9) having external screw threads (30). The rotating plunger (7) gets rotated by pressing the push button (8) which in turn by means of its flexing arm (29) traverses and its tapering tip which fits into the cavity between the consecutive external gear teeth (24) of the rotating plunger (7).

The distance traversed by the rotating plunger (7) in one stroke of the push button (8) corresponds to the preset volume of the liquid medicament that is to be dispensed. In the embodiments of the present invention the preset volume is about 50 microlitres. It may be noted that the fixing up of the quantum of distance traversed by the rotating plunger (7) can be done only at the manufacturing stage of the device and the user cannot change the settings of the volume to be dispensed. This indeed avoids the user to play with the device whereby the possibility of the unwanted i.e either extra or lesser amount of volume of liquid medicament delivery is totally avoided. Thus, the user cannot do any kind of self medication in terms of dose of the liquid medicament. This is indeed one of the inventive features of the device. The user therefore, if directed to take fixed number of drops, an optimum therapy can be achieved without any tampering of the device.

The device of the present invention, includes, one or more locking means to lock the rotating plunger (7) from returning to the first position from the traversed position. The locking means includes a piece which has spring like action for example a leaf spring like ratchet arm (18). However, it may be understood that the locking means can be in any shape and will provide the locking action as long as the spring effect is exerted. The spring may be in the form of a flexible arm, or a rod or a flat protrusion etc. The locking means stays in constant contact with the external gear teeth (24) of the rotating plunger (7) such that the teeth slip past the locking means when the rotating plunger (7) is rotating. Reverse motion is prevented when the locking means locks with the external gear teeth (24) of the rotating plunger (7) instead of slipping and because in the reverse direction of the rotating plunger (7), the locking means cannot be flexed. Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. It should be emphasized that the above- described embodiments of the present invention, particularly any "preferred" embodiments, are merely possible examples of the invention of implementations, merely set forth for a clear understanding of the principles of the invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.

Claims

Claims:

1. A device suitable for dispensing multiple doses of a liquid medicament, the device comprising

b) a rotating plunger (7) connected to a push button (8) and

c) locking means

wherein upon pressing the push button (8), the rotating plunger (7) rotates and traverses from the first position to a traversed position causing preset compression of the collapsible wall of the container (3) to dispense a preset volume of the liquid medicament, and wherein the rotating plunger (7) is locked from returning to the first position by the locking means, thereby preventing air from entering back into the container to maintain a sterile environment within the container (3)

2. A device as in claim 1, wherein the rotating plunger (7) comprises external gear teeth (24), internal screw threads (25) and a combination of flat surface (26) and spherical surface (27) at one end.

3. A device as in claim 2, wherein the flat surface (26) and spherical surface (27) of the ^• rotating plunger (7) on which the surface (28) of the container with a collapsible wall (3) rests.

4. A device as in claim 1, wherein the rotating plunger (7) is mounted on a threaded piece (9) having external threads (30).

5. A device as in claim 4, wherein the rotating plunger (7) is mounted on a threaded piece of the stationary screw (9) having external screw threads (30).

6. A device as in claim 5, wherein the external screw threads (30) of the stationary screw hold the internal screw threads (25) of the rotating plunger (7).

7. A device as in claim 1, wherein the push button (8) is connected to the rotating plunger (7) by means of a flexing arm (29) having tapering tip (43) wherein when the push button (8) is pressed, it slides along the guide rail (15) each provided in the external cover (4) and (5) the flexing arm (29) having the tapering tip (43) which fits into the consecutive external gear teeth (24) of the rotating plunger (7) and pushes the external gear teeth (24) of the rotating plunger (7), causing the rotaTyTnt)veTtien ffl rotating plunger (7).

8. A device as in claim 1 , wherein the volume of the liquid medicament that is dispensedis dependent on the distance traversed by the rotating plunger (7).

9. A device as in claim 1, wherein the locking means includes a ratchet arm (18) which is part of the stationary external cover (5).

10. A device as in claim 8, wherein the ratchet arm (18) locks with the external gear teeth (24) of the rotating plunger (7) to restrict the rotary movement of the rotating plunger (7) in a single direction.

1 1. A device as in claim 1 , wherein the collapsible walls are in the form of bellows or ribs or tubes or balloon.

12. A device as in claim 1, wherein the preset volume of the liquid medicament is about 50 microlitres.