Inhalation Device

Abstract

A dispensing device for dispensing finely divided medicament from a capsulelike container. A hollow elongated housing has at both ends thereof at least one passageway to permit passage of air, and one end is adapted for insertion into the mouth. A propellerlike member is rotatably mounted in the housing and has on the part thereof farthest from the end of the housing adapted for insertion into the mouth a mounting means adapted to receive the capsulelike container. Also included is a means for perforating the container.

Description

The present invention relates to a device for use in the application of medicaments in finely divided form by oral inhalation.

In order to dispense its contents a container of the finely powdered medicament must be perforated and the present invention relates to the provision of such perforating means integral with a dispensing device of the type which comprises a hollow elongated housing, suitably a tubular housing, having at both ends thereof one or more passageways to permit the passage of air and having one end thereof adapted for insertion into the mouth; and a propellerlike member rotatably mounted in the housing and having, on the part thereof furthest from that end of the housing adapted for insertion into the mouth, mounting means adapted to receive a container for the finely divided medicament, such as a gelatine or like capsule. (By the term "propellerlike member" is meant a member having two or more blades or vanes disposed about a central axis or hub, such that impingement of an airstream on the said vanes or blades tends to cause rotation of the member about said axis or hub).

The dispensing portion of the device of the invention may take a variety of forms and may, as described later, also be provided with a cover enclosing the device. However, in the dispensing portion of the device, it has been found that where the propellerlike member is rotatably mounted by means of a cylindrical shaft journaled in a tapered bearing tube, the bearing tube and shaft should have certain dimensional characteristics in order to optimize operation of the device. Thus, the bearing takes the form of an elongate cavity of circular cross section and the shaft is of substantially uniform circular cross section. The internal diameter of the bearing at its inner end (i.e., the end housing the free end of the shaft) is desirably from 1.5 to 6 percent preferably 2.5 to 5 percent, e.g., 3.75 percent greater than the diameter of the shaft and the internal diameter of the bearing at its outer end is equal to the diameter of the shaft plus from 1.3 to 3.5 percent e.g., about 2.5 percent of the internal length of the bearing, which may be, for example, from four to 10, preferably about seven, times the diameter of the shaft. The inner end wall of the bearing is preferably flat and the end of the shaft which engages with it is suitably of frustoconical shape, preferably terminating in a hemispherical tip portion, e.g., of a radius of about half that of the shaft. It will be appreciated that the movement of the propellerlike member in the housing should not be erratic and we therefore prefer that in this form of device the shaft and bearing tube be in rolling contact during the operation of the device.

The shaft and bearing should be rigidly mounted since we have found that undue flexibility of the shaft and bearing mountings may cause malfunctioning of the device. It is also preferred to constrict the airflow past the powder container in order to increase its velocity at this part of the device. This may be achieved by providing the tubular housing with a venturi. For ease of construction and use, it may be desired to form the hollow elongate housing in two separable parts, one having the mouthpiece, the rotatable propellerlike member and its mounting; the other having the air inlet and, where provided, the constricted or venturi portion of the housing. The provision of a separable housing facilitates insertion and removal of powder containers from their mounting on the propellerlike device.

It will be appreciated that while the shaft may be rigidly mounted and the bearing be rotatable, the shaft and bearing may be transposed and the bearing rigidly in the housing while the shaft, which carries the propellerlike member, is rotatably journaled therein. The term "dispensing device of the type described" is used herein, where the context permits, to denote both forms of bearing and shaft assembly.

Heretofore piercing means or perforating means has been provided adjacent the propellerlike member, but because the powder container is not held rigidly in position, the piercing means often does not pierce accurately and the containers have a tendency to shatter.

It is an object of the present invention to provide means for holding and piercing the containers which is integral with the dispensing device. Accordingly, there is provided a dispensing device of the type described above provided with means, mounted externally upon the device, for perforating a container for a finely divided medicament.

The term perforating means as used herein is intended to denote any apparatus which may be caused to perforate a container which is subsequently to be mounted within the dispensing portion of the device. For example the perforating means may merely comprise a sheathed pin or like projection which may be unsheathed by the user and used to pierce the powder container. However, it is preferred to provide the perforating means with a cup or like receptacle into which the powder container to be perforated is placed and to use some form of retractable perforating means which may be actuated to perforate the powder container in the receptacle.

Suitably, the container perforating means may take the form of one or more spring-loaded piercing members mounted in a housing on the device so that they are normally urged, by the springs, into an inoperative position, i.e., away from the container, but which may be pressed inwards to perforate the container by the action of pushbuttons acting on the piercing members. The piercing means may also comprise a pair of opposed sharpened piercing members connected by a bent resilient bridging member and means for urging the piercing members together to pierce a container located between them. In this case the piercing members will generally be formed in one piece with the bridging members of a resilient material such as spring steel, carbon steel or stainless steel. If the piercing members are formed of a corrodible material, such as spring steel or carbon steel, they may be plated, e.g., with nickel or chromium, to inhibit corrosion. In order to facilitate the piercing operation the piercing members are advantageously provided with stops which prevent too deep a penetration of one member into the capsule before the other member comes into operation, hence ensuring equal penetration by both members. The resilient bridging member may take the form of a simply bent strip or rod of material or may be provided with one or more turns to give better resistance to fatigue. The piercing members may be urged together by pushbuttons or, preferably, by sliding cams.

It has been found that, in order to obtain optimum perforation of a gelatine capsule, the perforating end of the piercing member should not be sharpened to a conventional conical point but should be sharpened with a plane face at an acute angle to the axis thereof. Further it is desirable that the piercing member should be so orientated that the capsule pierced therewith may be mounted in the dispensing portion of the device with the lip of the perforation which has been cut with the angled plane face removed from the propellerlike member.

As stated above, the perforating means is mounted externally upon the housing of the dispensing portion of the device. The position upon which it is mounted is, within reason, immaterial. However, for convenience it is preferred to mount the perforating means approximately half way along the tubular body of the dispensing portion of the device and to form the housing for the perforating means in the form of a lateral arm extending radially from the tubular housing. The arm may be provided with a receptacle into which a powder container is placed for piercing. In is preferred that the arm be moulded integrally with the tubular housing, the whole being made from, for example, a plastic such as a nylon, polystyrene or a rigid polyethylene.

Suitably the powder container used in the device is a capsule, for example a gelatine or plastic capsule, and conveniently the capsule perforating means is so arranged to provide two or more holes, suitably of about 0.6-0.65 mm. in diameter, desirably in the part of the capsule which will be furthest from the propellerlike member when in position, advantageously in the shoulders of the capsule. Where the perforating means is so arranged as to provide two or more holes in the container, these are conveniently positioned symmetrically around the container.

In a preferred version of the device of the invention, the dispenser and the perforating means are housed within a split shell cover which may be removed to permit the loading and piercing of a powder container in the piercing means and subsequent transfer of the pierced container to its mounting means on the propellerlike member. The cover acts to protect the device from damage due to dust and grit. Where the device is provided with such a cover it is convenient to use the housing for the perforating means as a support for an annular collar lying in a plane which is approximately at right angles to the longitudinal axis of the tubular housing of the dispenser. The collar may also be supported by struts mounted on the tubular housing. The collar is adapted to receive each half of the split shell cover in, for example, a snap fit which permits secure mounting of the cover yet enables ready removal of each half of the cover to expose the two ends of the tubular housing. As indicated above, the elongate housing of the device may be formed in two separable halves. Since that portion having the air inlet and the constricted or venturi portion will usually hinder access to the powder container mounting means, it is generally necessary to remove that portion of the housing during the loading or unloading of powder containers. It is, therefore, convenient to attach that part of the split shell cover enclosing the portion of the housing hindering free access to the container mounting means to that portion of the housing. By this means, removal of the shell cover also removes the housing. The attachment of the housing and cover may be by means of struts or the like.

The device according to the invention is suitable for the administration of medicaments for the alleviation of ailments of the respiratory tract and of the lungs. The device may also be used for the administration of medicaments having systemic action, for example, it may be used for the administration of antidotes to poisonous substances such as nerve gases as it provides a very simple method of carrying medicaments which have to be used rapidly or in emergency. If desired, the device of the insertion may be provided with clips, cuplike receptacles or the like on the lateral arm carrying the piercer or within the split shell covers, whereby a number of powder containers may be stored within the device for future use. By this means a user is provided with a device whereby a drug may be administered speedily and easily and with a ready supply of capsules for his immediate needs, for example a day's supply of four to six capsules.

By way of example a device according to the invention will be described with reference to the accompanying drawings in which FIG. 1 is a vertical section through the device and FIG. 2 is a view of the device from above with the upper cover and constricted portion of the housing removed. Like numerals denote like parts.

Referring now to FIG. 1 of the drawings, the device comprises a cigar-shaped tubular housing of approximately circular cross section comprising two engaging members 1 and 2, member 2 being provided with a mouthpiece 3 for insertion into the mouth of the user. Mounted rigidly in and coaxially with member 2 is a shaft 4 upon which is loosely and rotatably mounted propellerlike member 5 having blades 6 and an elongated tapered bearing tube. The internal diameter at the inner end of the bearing tube is about 3.75 percent greater than the diameter of shaft 4 and the internal diameter at the outer end of the bearing tube is equal to the diameter of shaft 4 plus about 2.5 percent of the internal length of the bearing, which is about seven times the diameter of shaft 4.

The tip of shaft 4 is conical in shape, having a cone angle of about 30.degree., and terminates in a substantially hemispherical portion having a diameter of about half the diameter of shaft 4.

The relative dimensions of the device, notably of the shaft, bearing tube and propellerlike member, may be varied over considerable ranges to produce a number of permutations which will give rise to satisfactory operation of the device. We have found that where the shaft 4 is a cold drawn stainless steel wire of diameter about 2.03 mm., and the bearing tube is a hard nylon having an internal diameter at its inner end of about 2.08 mm., and of about 2.44 mm., at its outer end and a length of about 12.7 mm., satisfactory operation of the device is achieved for a capsule of internal diameter about 6.3 mm., mounted on the propellerlike member with the base of its parallel walled portion about 5.1 mm. from the top of the bearing tube.

The propellerlike member 5 has a cup-shaped member 7 adapted to receive and hold a capsule or container or finely powdered medicament (shown in dotted outline).

The member 1 has a constriction 8 which acts as a venturi and increases the velocity of the airstream past the capsule when a user inhales air through the mouthpiece 3. Mounted externally upon the waist of the housing 2 is a radial sidearm which carries a cup-shaped receptacle 9 for a powder container and a needle piercer 10 mounted in a carrier 11 which carrier is adapted to slide forward against a return spring 12, housed within the sidearm and which bears against the carrier slide. The forward movement of carrier 11 carries the needle 10 across the mouth of the receptacle 9.

The receptacle 9 is provided with slots 13 through which the needle 10 may pass when it is moved forward.

The free end of the sidearm also acts as a support for a collar 14 which encircles the waist of the cigar-shaped tubular housing and the sidearm The member 2 also carries support struts 15 (of which only one is visible) for the collar 14. The collar is provided with an upper and a lower rim which are adapted to accept an upper and lower cover 16 and 17 in a snap fit. The two covers form the halves of a split shell which encases the whole of the device. While the overall configuration of the collar 14 and covers 16 and 17 is of minor significance, it is essential that, in this form of the device, the collar 14 should be spaced from the walls of the members 1 and 2 and from the sidearm to provide air passages 18 across the plane of the collar. The air passages 18 are more readily visible in FIG. 2 which is a top view of the device with the top cover 16 and member 1 removed.

It will of course be appreciated that the elongated bearing tube may be mounted rigidly and substantially coaxially with member 2 and the shaft 4 may be mounted on the propellerlike member 5.

In use, the top cover 16 and the attached member 1 are removed, a powder container is inserted in the receptacle 9 and pierced by forward movement of the needle 10 and carrier 11 such that the needle 10 passes through the powder container. The needle is withdrawn by the action of the return spring 12 and the container then inserted in the cup 7 of the propeller 5. It will be appreciated that the container is mounted so that powder may issue from the perforations, in this case with the pierced end directed away from the mouthpiece 3. The upper cover 16 and member 1 are then replaced and the lower cover 17 removed, exposing the mouthpiece 3. The user sucks through the mouthpiece drawing a stream of air through the tubular housing via the air passages 18. The stream of air causes the propeller 5 to rotate and vibrate. The powder in the container is dispensed into the airstream and is inhaled by the user.

Claims

We claim:

1. A dispensing device comprising a hollow elongated housing having at both ends thereof at least one passageway to permit the passage of air and having one end thereof adapted for insertion into the mouth, a propellerlike member rotatably mounted in the housing and having, on the part thereof furthest from that end of the housing adapted for insertion into the mouth, mounting means adapted to receive a container for a finely divided medicament, and means mounted externally upon the device for perforating a container for a finely divided medicament, said externally mounted means having therein a recess opening outwardly of the externally mounted means which recess has a size and shape for receiving substantially the entire medicament container and holding the container firmly with only a small portion of the container projecting from the recess, and further having container piercing means movably mounted relative to said externally mounted means for movement a distance at least equal to the distance across said recess, and a single piercing member on said piercing means closely adjacent the recess opening and movable completely across said recess during movement of said piercing means for perforating both sides of the container, whereby the medicament container is held tightly during piercing and the piercing member moves across the recess opening close to the top surface of said externally mounted means to carry out precise piercing of the medicament container to reduce the danger of shattering the medicament container.

2. A device as claimed in claim 1 further comprising a housing on the device, and said piercing means comprises a spring-loaded member mounted in the housing.

3. A device according to claim 1 wherein the perforating means has a lateral sidearm provided on the elongated housing and extending radially from the elongated housing, said piercing means being mounted on said sidearm and said sidearm having said recess therein.

4. A device according to claim 1 wherein the piercing member has a sharpened end with a plane face at an acute angle to the axis thereof.