COUNTER MOUNTING TO AN EXISTING PMDI Field of the Invention

This invention relates to a counter, and more particularly, but not exclusively, to a mechanical dosage counter for a pressurised metered dose inhaler.

Background of the Invention

It is known to dispense medication (eg. for asthma) by way of a pressurised metered dose inhaler (pMDI), sometimes referred to as a "puffer". However, there exists a problem in that it is not possible to readily determine whether there is still active medicant in the inhaler as the propellent remains in an aerosol canister of the inhaler long after the active medicant has been totally consumed. Accordingly, there is a risk the user will continue using the inhaler only to receive propellent with little or no active medicant, or will dispose of the inhaler (or the canister of the inhaler) before it is fully used.

There have been a number of proposed solutions to the problem of determining how much medication actually remains in pMDIs once use has commenced. However, these have required redevelopment of the pMDI, re-tooling by the manufacturer of the pMDI and, typically, re-approval of the product which is time consuming. A lengthy approval poses significant disadvantages and opportunity cost issues for a pMDI manufacturer, which include economic costs, compliance/regulatory burdens and delays in time to market. Furthermore, designs requiring redevelopment may necessitate a stop on current pMDI production of units without counters.

Examples of the present invention seek to overcome or at least alleviate one or more of the above disadvantages.

Summary of the Invention

In accordance with the present invention, there is provided a counter including a mounting portion for mounting the counter to a pressurised metered dose inhaler, an actuator movable relative to the mounting portion for actuating the inhaler when the counter is mounted to the inhaler, and an indicator which is driven in response to operation of the actuator so as to provide a visual indication related to an accumulated number of actuations of the inhaler.

Preferably, the mounting portion is adapted for fitment relative to a body of the pressurised metered dose inhaler, and the actuator is adapted for pushing a canister of the inhaler into the body so as to actuate the inhaler. More preferably, the mounting portion includes a surround for fitting over an opening of the body, and the actuator is adapted for pushing the canister into the body through the opening so as to actuate the inhaler.

Preferably, when mounted to the inhaler, the counter is remote from a medicant flow path of the inhaler.

Preferably, the actuator has linear motion, the indicator has rotational motion, and the counter includes a mechanism for translating linear motion of the actuator into rotational motion of the indicator. Preferably, the mechanism includes angled teeth on the actuator and mating angled teeth on a ratchet, whereby interaction between the angled teeth on the actuator and the ratchet cause the ratchet to rotate incrementally relative to the actuator with each actuation of the inhaler. Even more preferably, the ratchet includes one or more protruding arms for engaging with the indicator so as to rotate the indicator incrementally once every predetermined number of actuations of the inhaler.

Preferably, the counter uses recoil of the canister relative to the body to drive the indicator;

Preferably, the indicator displays a number corresponding to an estimate of the number of doses remaining in, the inhaler.

Brief Description of the Drawings

The invention is described, by way of non-limiting example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a counter in accordance with an example of the present invention, shown mounted to a conventional pressurised metered dose inhaler and transparent to show inner working parts;

Figure 2 is a side view of the counter of Figure 1, shown prior to actuation of the inhaler;

Figure 3 is a side view of the counter of Figure 1 , shown with a button portion of the counter in a depressed state;

Figure 4 is a side view of the counter of Figure 1, depicting recoil of the button portion;

Figure 5 is a side view of the counter of Figure 1, showing movement of an indicator of the counter in response to operation of the button portion;

Figures 6(a) to (e) show front, side, rear, cross-sectional and top views of a counter in accordance with another example of the present invention, the counter shown mounted to a conventional pressurised metered dose inhaler ;

Figure 7 shows a side perspective view of the counter shown in Figures 6(a) to (e);

Figure 8 shows a perspective view of the counter shown in Figures 6(a) to (e), with a housing of the counter shown transparent;

Figure 9 shows an inverted perspective view of the housing of the counter shown in Figures 6(a) to (e);

Figure 10 is an underside perspective view of the button portion of the counter shown in Figures 6(a) to (e);

Figure 11 is an upper perspective view of a ratchet portion of the counter shown in

Figures 6(a) to (e);

Figure 12 is an upper perspective view of an indicator dial of the counter shown in Figures 6(a) to (e); and

Figure 13 is a perspective view of two counters in accordance with another example of the present invention.

Detailed Description

A counter 10 in accordance with an example of the invention is shown in Figure 1. The counter 10 includes a mounting portion 12 for mounting the counter 10 to an existing pressurised metered dose inhaler 14 and an actuator in the form of a button portion 16 movable relative to the mounting portion 12 for actuating the inhaler 14 when the counter 10 is mounted to the inhaler 14. The mounting portion 12 has a window 18 displaying an indicator 20 which is driven in response to operation of the button portion 16 so as to provide a visual indication related to an accumulated number of actuations of the inhaler 14.

More particularly, the indicator 20 is arranged to display a number visible to a user through the window 18, the number corresponding to an estimate of the number of doses remaining in the inhaler 14.

The mounting portion 12 is adapted for fitment relative to a body 22 of the pressurised metered dose inhaler 14, such that the counter 10 is able to be used with existing pressurised metered dose inhalers. In particular and advantageously, the counter 10 is able to be retro-fitted to existing conventional pressurised metered dose inhalers which do not have integral counters. The mounting portion 12 includes a surround 24 for fitting over an opening 26 of the body 22, and the button portion 16 is adapted for pushing an aerosol canister 28 of the inhaler 14 into the body 22 through the opening 26 so as to actuate the inhaler 14.

With reference to Figure 2, as the medicant flow path 30 is at an opposite end of the inhaler 14 to the opening 26 over which the counter 10 is mounted, the counter 10 is remote from the medicant flow path 30. It is hoped that this will facilitate expediting of the approval process for the counter 10 to be brought to the marketplace.

Figures 2 to 5 show operation of the inhaler 14 with the counter 10 fitted. With reference to Figures 2 and 3 in particular, as can be seen, pressing of the button portion 16 of the counter 10 results in pushing of the aerosol canister 28, whereby medicant is emitted along the medicant flow path 30 in much the same way as would be done if the counter 10 were not present and the user were to press the end of the canister 28 directly in the conventional manner of using pressurised metered dose inhalers.

The button portion 16 has linear motion, as depicted by arrow 32 in Figure 2, the indicator 20 is in the form of a' dial having rotational motion, and the counter 10 includes a mechanism 34 for translating the linear motion of the button portion 16 into the rotational motion of the indicator dial 20. The mechanism 34 includes angled teeth 36 on an abutting surface of the button portion 16, and correspondingly-shaped mating angled teeth 38 on a ratchet wheel 40, whereby interaction between the angled teeth 36 of the button portion 16

and the angled teeth 38 of the ratchet wheel 40 cause the ratchet wheel 40 to rotate incrementally relative to the button portion 16 with each actuation of the inhaler 14. More particularly, as shown in Figures 2 to 5, the ratchet wheel 40 rotates incrementally by the angular rotation of one angled tooth 38 with each depress/release cycle of operation of the button portion 16.

The ratchet wheel 40 also has one or more protruding arms 42 for engaging with the indicator 20 so as to rotate the indicator 20 incrementally once every predetermined number of actuations of the inhaler 14. In the particular example shown, the indicator 20 has numeric markings in intervals of 10, thus the indicator is arranged to rotate incrementally once every 10 actuations of the inhaler 14. To achieve this, the ratchet wheel 40 has 10 angled teeth, and a single protruding arm 42. The indicator 20 has teeth 44 which face toward the ratchet wheel 40, one tooth per numeric marking on the indicator 20, and a transfer gear 46 is provided to transfer rotational motion between the protruding arm 42 and the indicator 20.

The button portion 16 has outward extensions 48 which run within corresponding vertical guiding grooves on an inside perimeter surface of the counter housing 50 so as to guide linear movement of the button portion 16 relative to the housing 50. In the example shown in Figures 1 to 5^ the ratchet wheel 40 also has outward extensions 52 which are arranged to run within the guiding grooves on the inside perimeter surface of the counter housing 50.

Once actuation of the inhaler 14 has taken place and the button portion 16 is released by the user, the recoil spring-like return force of the canister 28 relative to the body 22 causes the button portion 16 and the ratchet wheel 40 to be returned upwardly to their respective rest positions relative to the counter housing 50.

A more detailed step-by-step description of operation of the counter 10 as shown in Figures 2 to 5 is below:

Figure 2:

(i) Initially the button portion 16 and ratchet wheel 40 are held with mating angled tooth faces in contact.

(ii) The button portion 16 is pressed from above by the user. (iii) The button portion 16, ratchet wheel 40 and aerosol canister 28 travel downward relative to the body 22 of the inhaler 14.

Figure 3:

(iv) The dose is administered by the aerosol canister 28. (v) The angled teeth 38 on the top surface of the ratchet wheel 40 then coincide with a break in the grooves of the counter housing 50. (vi) Co-planar surfaces of the angled teeth 38 of the ratchet wheel 40 and the angled teeth 36 of the button portion 16 allow the ratchet wheel 40 to rotate incrementally (the angle of rotation of the ratchet wheel 40 is governed by the number of segments).

Figure 4:

(vii) The button portion 16 and the ratchet wheel 40 travel upward, toward the original starting position. (viii) The ratchet wheel 40 continues to rotate during return upward travel.

Figure 5:

(ix) At completion of travel the button portion 16 and ratchet wheel 40 are located in their original position, with the ratchet wheel 40 rotated by one increment.

(x) Upon one full rotation of the ratchet wheel 40 the protruding arm 42 interacts with the transfer gear 46.

(xi) The transfer gear 46 then interacts with the indicator dial 20 and causes the indicator dial 20 to rotate.

(xii) The number displayed in the counter window 18 ticks over to display the next number (in the case of the example shown, every 10 doses).

In the example shown,- the number displayed in the window 18 corresponds to an estimate of the number of doses remaining in the inhaler canister 28, and decreases by 10 for every 10 actuations of the inhaler 14.

A counter 10 in accordance with another example of the present invention is shown mounted to a conventional pressurised metered dose inhaler 14 in Figures 6(a) to (e). The cross-sectional view in Figure 6(d) is taken along the line A-A shown in Figure 6(a). The counter 10 is similar to the counter of Figures 1 to 5, and like features are labelled with like reference numerals. The most significant differences between the examples shown in

Figures 6(a) to (e) and Figures 1 to 5 lie in the mechanical configuration of the counter 10 of the second example, and these will be described in more detail with reference to Figures

7 to 12.

Figures 7 and 8 show the counter 10 of the second example in its assembled configuration, with Figure 8 illustrating the configuration of the internal moving parts by virtue of the housing 50 being shown transparent. With reference to Figure 8 in particular, a different configuration is used for the ratchet wheel 40, the indicator dial 20, and the housing 50.

Figures 9, 10, 11 and 12 show detailed views of the isolated parts of the housing 50, button portion 16, ratchet wheel 40, and indicator dial 20, respectively.

As can be seen, instead of using a transfer gear 46 as in the previous example, drive is transferred from the ratchet wheel 40 to the indicator dial 20 by virtue of angled deflecting protrusions 54 which extend upwardly from the indicator dial 20, and corresponding deflecting protrusions 56 which extend downwardly from the ratchet wheel

40. In the example shown, the indicator dial 20 has two deflecting protrusions 54, and the

ratchet wheel 40 has two corresponding deflecting protrusions 56, the protrusions 54, 56 being spaced apart such that the indicator dial 20 rotates by one increment for a certain number of actuations of the inhaler 14, that number being the same as interval of the stepping of the numerals on the indicator dial 20.

Figures 8 and 9 also show that the inside of the housing 50 of the counter 10 is provided with two saw-tooth ridges 58, 60, a first saw-tooth ridge 58 for assisting rotation of the ratchet wheel 40, and a second saw-tooth ridge 60 for assisting rotation of the indicator dial 20. The first and second saw-tooth ridges 58, 60 also serve to lock the ratchet wheel 40 and the indicator 20 in rotational position relative to the housing 50 when the button portion 16 is in the released state. When the button portion 16 is in the depressed state, downward movement of the ratchet wheel 40 and the indicator dial 20 relative to the housing 50 enables the wheel 40 and the dial 20 to rotate relative to the housing 50 as they are lowered beneath the respective saw-tooth ridges 58, 60. A series of deformable springs 62 integral to the indicator dial 20 serve to bias the indicator dial 20 against the second saw-tooth ridge 60.

Figure 13 shows a pair of counters 10 in accordance with another example of the present invention, one counter 10 shown mounted to a conventional pressurised metered dose inhaler 14, and the other shown resting on a surface, with a pen shown for size reference. In accordance with this example, the overall height of the counter 10 from the top of the canister to the top of the button portion 16 has been reduced to facilitate use by children and adults with small hands.

Advantageously, examples of the present invention provide a mechanical, sit-on- top counter to count down the dosage that remains in order for a drug user to accurately determine when his or her medication has run out and a new inhaler/canister needs to be purchased. The counters are stand-alone solutions that fit onto pre-existing inhalers, and do not require re-engineering of the inhalers. The counters are mechanical and do not require electrical power to operate.

The counter has been described above by way of examples only, and modifications are possible within the scope of the invention.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Throughout this specification, unless the context requires otherwise, the word

"comprise", or variations such, as "comprises" or "comprising", will be understood to imply the inclusion of a stated step or integer or group of steps or integers but not the exclusion of any other step or integer or group of steps or integers.