IE911795A1

IE911795A1 - Application device

Info

Publication number: IE911795A1
Application number: IE179591A
Authority: IE
Original assignee: Kalumburu Pty Ltd; Kaye Lynette Howell
Priority date: 1990-05-29
Filing date: 1991-05-27
Publication date: 1991-12-04
Also published as: ZA914029B; WO1991018535A1

Abstract

An application device for topical aplication of a liquid comprises a closed container (11, 12) which holds a reserve of liquid. A wick (17) protrudes from the container (11, 12), the wick having its inner end in contact with the liquid. The container top (20) has an absorbent sponge (22) on its underside which is in contact with the outer end of the wick (17) when the top (20) is screwed onto the container, thereby enabling the absorbent sponge (22) to be charged with liquid from within the container through the wick (17). To apply the absorbed liquid, the top (20) is removed and the sponge (22) is wiped on the skin. The sponge (22) has a predetermined absorption capacity, thereby limiting the maximum dose which a patient may receive. The restricted flow of liquid through the wick member also delays recharging of the sponge and hence ensures a minimum period between applications of a liquid.

Description

APPLICATION DEVICE THIS INVENTION relates to a device for dermal or transdermal application of liquids or creams. The application device of this invention is particularly, but not solely, suitable for the topical application of liquids and creams which are inherently toxic and must therefore be administered in controlled dosages.

BACKGROUND OF THE INVENTION It is recognised that dosages of substances which are topically applied for transdermal ingestion by the body must be accurately controlled. For example, various known arthritis creams which contain methyl salicylate should be applied in limited quantities. When methyl salicylate contacts the skin, there is considerable transdermal passage of salicylate, and salicylate poisoning may occur if excess cream is applied. The maximum dosage should therefore be carefully controlled.

Cortisone creams provide further examples of substances whose transdermal application must be controlled.

There are many ailments which are treated topically with cortisone. Due to the high transdermal absorption of cortisone in liquid form, it is important that the cortisone be applied with a controlled maximum dosage.

MINOXIDIL is another drug which can be applied transdermally, for promoting hair growth. This drug however, increases blood pressure and its usage must be carefully controlled. As users anxious to accelerate hair growth may be likely to apply it in excess of prescribed doses, the availability of the drug must be restricted.

Yet another example of a substance whose transdermal application must be controlled and limited is nicotine. It is now common practice to administer nicotine topically in order to satiate nicotine craving, to thereby assist in treatment for reducing or eliminating the need to smoke. However, the transdermal dosage of nicotine must be carefully controlled since nicotine is easily absorbed transdermally, and is extremely toxic, even in relatively small doses.

It is known to apply nicotine transdermally in controlled dosages by means of dermal patches. The patient applies a nicotine-coated bandage or plaster which contains a known quantity of nicotine. This dermal patch is changed at regular intervals, typically every 24 hours. Although the dermal patches have achieved limited success in smoking therapy, they do not cater for the large variation in nicotine requirements of individual users. Although the patches could be made in varying dosage strengths, the different dosage versions would pose a marketing problem. Furthermore, the same user may require different dosages at different times. It is well known that food and drink intake, and other activities during the day, cause variation in the plasma level of nicotine. The dosage needs of a particular smoker are therefore not consistent throughout the whole day, and a dosage system which does not cater for varying needs is unlikely to meet with market success.

It is also known to apply nicotine using a roll-on device similar to a conventional deodorant roll-on applicator. This device contains liquid nicotine solution of desired strength and can be applied to the skin at desired intervals in desired dosages. For example, larger doses may be administered after a meal, while smaller doses may administered in the evening when nicotine requirements are less. Such a roll-on device therefore permits far more variable dosing than the dermal patch system as the dosage is entirely in the hands of the patient.

However, unlimited patient-controlled dosing is inherently dangerous. A child may mistake the roll-on applicator for a conventional deodorant and apply far more than the toxic dose in a short period of time. Further, efficacy trials published in The Australian Journal of Medicine disclose a high rate of nausea amongst users of rollon nicotine applicators. Such nausea is an early sign of toxicity, indicating that the patient has exceeded his or her nicotine tolerance level. Total aversion of the product has occurred when patients have been frightened by the sudden onset of nausea.

Thus, while a nicotine application device should permit different doses to be applied to meet the varying nicotine needs of the individual patient at different times, the device should limit the maximum dosage available to the patient at any particular time or at least not allow total control of the dosage by the patient. The known application devices do not meet the requirements.

There are various known swab applicators which comprise a wad of absorbent material adjacent a tube containing liquid medicament. Examples of such swab applicators can be found in Australian patent applications nos. 35535/89 and 67905/87, as well as U.S. patents nos. 3,958,571; 3,519,364; 4,430,013; 4,218,155 and 3,757,782. Such known swab applicators normally require the breaking or rupturing of a seal between the tube and the wad, or a seal at the other end of the tube, or the breaking of the tube itself, to permit the liquid medicament in the tube to flow into the swab and saturate it. Such known swab applicators however, are designed to be used once only and thereafter discarded. That is, substantially all of the medicament in the tube is absorbed by the applicator on first absorption. Such known swab applicators are therefore unsuitable for continued treatment by a patient. In addition, those swab applicators which rely on the rupturing of a capillary tube have the inherent disadvantage of a jagged edge which may cause stick injuries .

It is an object of the present invention to provide an application device which allows a substance to be applied at intervals in varying dosages, but limits maximum dosage.

SUMMARY OF THE INVENTION In one broad form, the present invention provides an application device suitable for applying a liquid to the skin of the user, comprising: a container adapted to hold a quantity of the liquid; a liquid transport member having one end within the container and another end outside it, the liquid transport member permitting the liquid to flow through it at a restricted flow rate; and an absorbent member for topical application of the liquid, the absorbent member having a predetermined liquid absorption capacity, whereby in use the absorbent member is placed in contact with the other end of the liquid transport member to be charged to a predetermined maximum quantity with liquid from the container through the liquid transport member over a predetermined minimum period of time.

Throughout the specification, the term liquid, where the context permits, is to be interpreted to include semi-liquid or liquescent materials such as creams, ointments, gels and the like.

Preferably, the container is a sealed container and may suitably be a closed tube or vial. The liquid transport member is typically a wick, capillary tube, or similar device through which liquid passes by capillary action, osmosis, diffusion or other wicking effect. The term wick includes fibrous rods or similar devices made from foraminous ceramics, woven or non-woven fibrous materials, or particular materials. One end of the liquid transport member is. located within the container in contact with the liquid in that container, while the other end has an end surface outside the container for contact with the absorbent member.

The absorbent member may suitably be a sponge, pad, wad, swab, packing or similar absorbent material.

In use, the absorbent member is placed in contact with the outer end of the liquid transport member. Liquid within the container passes through the liquid transport member at a restricted rate and is absorbed by the absorbent member. However, the absorbent member has a finite liquid absorption capacity. Once the absorbent member has been charged to its capacity with liquid, no further liquid will be absorbed. Moreover, the charging of the absorbent member with the liquid will take at least a predetermined minimum period of time due to the restricted flow rate through the liquid transport member.

The charged absorbent member may then be used to apply the liquid topically, for example by wiping over a selected portion of the patient's skin. The absorbent member is then replaced in contact with the other end of the liquid transport member to be recharged to its capacity. Typically, the absorbent member is located on a cap designed to fit on the container so that the absorbent member will be recharged automatically whenever the cap is replaced.

The application device has several advantages. First, as the absorbent member has a limited capacity, the maximum dosage at any one time is limited to the predetermined capacity. The capacity limit therefore prevents excessive single doses being applied.

Secondly, as the flow rate through the liquid transport member is also limited, the absorbent member will require a minimum period to recharge. This time delay prevents overdosing by too frequent repetitive application.

Thirdly, the application device permits flexibility of application. The device can be used as required by the patient, with the security of a controlled maximum dosage and minimum period between reapplication. The device can therefore cater to the varying needs of different patients, yet minimises the potential for patient abuse.

In order that the invention may be more fully understood and put into practice, a preferred embodiment thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partial sectional elevation of the application device of the preferred embodiment; Fig. 2 is an exploded perspective view of the application device of Fig . 1; and Fig. 3 is a graph illustrating typical absorption characteristics of the sponge pad of the device of Fig. 1.

DESCRIPTION OF PREFERRED· EMBODIMENT The application device illustrated in Figs. 1 and 2 is suitable for topical transdermal application of a liquid or semi-liquid substance. The illustrated device 10 is particularly suitable for transdermal application of nicotine solution.

The device 10 comprises an open-top vial-like container 11 which typically is made of plastic, glass, metal or other suitable material, and is designed to hold the liquid to be applied, for example a nicotine solution. After filling the container 11 with the desired quantity of liquid, the top opening of the container 11 is closed by an insert 12. An internal bead 13 around the top rim of container 11 engages into an annular channel 14 around the top rim of the insert 12 to thereby snap-lock the insert 12 in container 11 and prevent tampering.

The base of insert 12 is recessed below the top of the container 11 and has a socket formation 15 formed therein as can be seen more clearly in Fig. 1. A wick holder 16 is snap fitted into the socket formation 15 as also illustrated in Fig. 1. The wick holder 16 comprises two half-sections 16A, 16B having opposing vertical channels (see Fig. 2). When the halves 16A, 16B are brought together, the opposing channels form a through bore in which a wick 17 is located in use. The diameter of the through bore is preferably less than the diameter of the wick so that when the wick holder assembly is snap fitted into socket 15, and thereby held together, the wick 17 will be held in a tight fit within the composite bore in the wick holder 16. Additionally, a tooth 18 may protrude laterally within a channel in at least one of the halves 16A, 16B to engage the wick 17 and prevent the wick from being pulled out of container 11.

Typically, the container 11, insert 12 and wick holder 16 are of moulded plastics construction. However, any other known suitable material may be used.

The lower end of wick 17 extends into the liquid within container 11, while the upper end of wick 17 protrudes above the wick holder 16. However, the upper end of the wick is located below the upper rim of the container 11 to thereby prevent the wick 17 being rubbed directly on the skin.

The wick may be of any known suitable material which has a restricted liquid flow rate therethrough. In this manner, the liquid within the container 11 will not flow out in the event that the container is knocked over or up-ended. A capillary tube may be used as an alternative to the wick 17, and the term wick is intended to cover similar devices which operate by capillary action, osmosis, diffusion or equivalent “slow transport action.

The insert 12 may be glued to the container 11, and the wick holder 16 may be glued into the insert 12, to increase the security of the device. Preferably, a narrow passage is provided between the insert 12 and the container 11 so as to vent the interior of the container 11 to the atmosphere but not readily permit passage of liquid therethrough. The venting of the interior of container 11 assists in the uptake of liquid by the wick 17.

The application device 10 also includes a threaded or bayonet cap or top 20 as shown in the drawings. The top 20 preferably has a pair of side wings 21 to assist in gripping. An absorbent member 22 is held in place against the bottom face of top 20 by a collar 23 which is snap fitted onto the bottom portion of top 20, as can be seen more clearly in the sectional view of Fig. 1. The absorbent member 22 is configured so that a portion thereof protrudes through the bottom aperture in collar 23.

The base of insert 12 is also provided on its upper side with an upstanding annular flange 19 within which the protruding portion of absorbent member 22 is received when the top 20 is screwed into insert 12. The annular flange 19 engages in the bottom aperture of collar 23 so as to generally seal the area around the absorbent member 22 and thereby prevent air drying of the absorbent member or leakage of fluid.

Typically, the absorbent member 22 is a sponge, preferably a cellulose sponge, but any other suitable β absorbent pad or wad may be used.

The absorption characteristics of a typical preferred sponge 22 are illustrated in Fig. 3. The sponge 22 will absorb liquid at a relatively constant rate until it reaches its absorption capacity, at which time it will not substantially absorb any more liquid.

In use, the liquid within container 11 travels up through wick 17 at a slow rate and is absorbed by sponge 22 until the sponge has reached its absorption capacity. The rate of flow through wick 17 can be preselected by appropriate choice of wick material, wick diameter and length.

The absorbed liquid can be applied simply by unscrewing top 12 and wiping the sponge 22 on the desired part of the body. The maximum dosage is limited by the absorption capacity of sponge 22. After application, the top 20 is replaced on container 11 so that the sponge 22 will automatically contact the upper end of wick 17, and be recharged with liquid from within the container through the wick. The recharge time, and hence the minimum period between applications, is governed by the rate of flow through wick 17 as well as the absorption rate of sponge 22. These factors ensure that the patient will not overdose by applying excessive single dosages or applying the liquid too frequently.

The foregoing describes only one embodiment of the invention, and modifications which are obvious to those skilled in the art may be made thereto without departing from the scope of the invention as defined in the following claims.

For example, although the preferred embodiment has been described with particular reference to its use as an applicator for a nicotine solution, the device can also be used for applying other therapeutic or liquid substances generally, particularly toxic substances whose dosages must be restricted.

Claims

CLAIMS:

1. An application device suitable for dermal application of a liquid, comprising: a container adapted to hold a quantity of the liquid; a liquid transport member having one end within the container and another end outside it, the liquid transport member allowing restricted flow of the liquid therethrough; and an absorbent member for application of the liquid, the absorbent member having a predetermined liquid absorption capacity, whereby in use the absorbent member is placed in contact with the other end of the liquid transport member to be charged with liquid from the container through the liquid transport member over a predetermined minimum period of time.

2. An application device as claimed in claim 1, wherein the liquid transport member comprises a wick device.

3. An application device as claimed in claim 1, wherein the absorbent member is comprised of sponge material.

4. An application device as claimed in claim 1, further comprising a top for the container, the absorbent member being located on the bottom of the top such that when the top is placed on the container, the absorbent member is in contact with the other end of the liquid transport member.

5. An application device as claimed in cla-im 1, wherein the container is a substantially closed container, and comprises a first open-topped vessel adapted to receive and hold a desired quantity of the liquid; and an insert member fitted to the top of the vessel to substantially close the vessel; the insert member having an opening therethrough in which the liquid transport member is located.

6. An application device as claimed in claim 5, wherein the liquid transport member is a wick device, further comprising a wick holder assembly comprising a pair of abutting members having channels in their opposing faces which form a composite bore in which the wick member is located in use, the wick holder assembly being retained within the opening in the insert member in a tight fit such that the wick member is clamped between the abutting members.

7. An application device as claimed in claim 6, wherein at least one of the abutting members has a tooth projecting into the wick member so as to prevent linear movement of the wick member through the wick holder.

8. An application device as claimed in claim 5, further comprising a narrow vent opening between the insert member and the vessel to vent the interior of the vessel to the atmosphere.

9. An application device as claimed in 5, wherein the other end of the liguid transport member is located within the insert member below the top rim of the container.

10. An application device as claimed in claim 1, wherein the liquid comprises a nicotine solution.

11. An application device for dermal application of a liquid, comprising a substantially closed container adapted to hold the liquid; an elongated wick member having one end within the container in contact with the liquid in use, and its other end outside the container, the wick member permitting the liquid to pass therethrough at a limited flow rate; and a cap for the container, the cap having on its underside an absorbent member such that when the cap is placed on the container, the absorbent member contacts the other end of the wick member and is charged with liquid from the container through the wick member, whereby, in use, the absorbent member can be used to apply the absorbed liquid to the user's skin by wiping, and thereafter be recharged with further liquid from the container through the wick member.

12. An application device as claimed in claim 11, wherein the container comprises a vial-like vessel, an insert member adapted to be fitted within the open top of the viallike vessel, the insert member having a base located below the top of the vessel, and wick holder means located in the base of the insert member for securely holding the wick member therein.

13. An application device as claimed in claim 12, further comprising an annular upstanding flange on the base of the insert member adapted to receive the absorbent member therewithin when the top is placed on the container.

14. An application device as claimed in claim 11, wherein the absorbent member is at least partially formed of sponge material, the absorbent member being retained on the underside of the top by an annular cap fitted to the top, at least part of the absorbent member protruding through the aperture in the annular cap for contact with the wick member in use.

15. An application device as claimed in claim 11, wherein the absorbent member has a predetermined liquid absorption capacity.

16. An application device suitable for dermal application of a liquid, substantially as herein described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.

17. An application device suitable for dermal application of a liquid, substantially as herein described with reference to Figure 3 of the accompanying drawings.

18. The features described in the foregoing specification, or any obvious equivalent thereof, in any novel selection.