IMPROVED INHALATION APPARATUS

Abstract: An inhalation apparatus (1) for dispensing a product comprises a housing (2) for a pressurized dispensing container (3) and including a portion (8) adapted to receive a valve stem (9) of the pressurized dispensing container, an air inlet to said housing and a mouthpiece (7). The apparatus further comprises duct means communicating with the housing for conveyance of product towards the mouthpiece, and an air flow controller in the form of an annular membrane (12) adjacent to the valve stem receiving portion. The air flow controller (12) is biased to a first position corresponding to no or a minimum flow of air from the air inlet to the mouthpiece, and is movable in use by the pressurized dispensing container to a second position corresponding to a maximum flow of air from the air inlet to the mouthpiece, continued movement of the pressurized dispensing container causing a dose of product to be dispensed into the maximum air flow, the air flow being created by a user applying suction to the mouthpiece.

Description: IMPROVED INHALATION APPARATUS This invention relates to an inhalation apparatus for dispensing substances for inhalation and, in particular, but not exclusively, for dispensing medicinal products in aerosol form from a pressurised dispensing container. It is known to provide a sensor in an inhalation apparatus to detect inhalation by the user in order to synchronise with inhalation the release into the inhaled air flow of the substance to be inhaled. It is, for example, important in the administration of aerosol products for the relief of asthma that the timing of the dispensing operation should be carefully controlled to ensure maximum deposition of substance in the user's lungs. It is known from GB 2266466 to provide an electrically operated dispensing means responsive to a signal generated by a sensor which is responsive to a flow of air through the passageway. The disadvantage of this solution is that the apparatus is expensive. An object of the present invention is to provide dispensing means in which mechanical means are used to co-ordinate the release of the substance with the inhalation. The present invention therefore provides an inhalation apparatus for dispensing a product comprising a housing for a pressurised dispensing container and including a portion adapted to receive a valve stem of the pressurised dispensing container, an air inlet to said housing and a mouthpiece, said apparatus further comprising duct means communicating with the housing for conveyance of product towards the mouthpiece, and an air flow controller adjacent to the valve stem receiving portion, said air flow controller being biased to a first position corresponding to no or a minimum flow of air from the air inlet to the mouthpiece, and being movable in use by the pressurised dispensing container to a second position corresponding to a maximum flow of air from the air inlet to the mouthpiece, continued movement of the pressurised dispensing container causing a dose of product to be dispensed into the maximum air flow, the air flow being created by a user applying suction to the mouthpiece. An advantage of the present invention is that the dispensation of the medicament is synchronised with inhalation of the user using an inexpensive inhalation apparatus. A further advantage is that the presence of the first air flow allows a minimum volume flow rate of air through the housing, into the mouthpiece and into the user's mouth even when the air flow controller is in the first, sealed position. This is advantageous in that it helps to prevent the danger of the user panicking by being unable to inhale any quantity of air. Preferably the volume flow rate of the minimum air flow is smaller than the volume flow rate of the maximum air flow. Preferably the maximum volume flow rate is between 8 and 12 times the minimum volume flow rate. An advantage of the increased second volume flow rate compared to the first volume flow rate is that a sufficient air flow is established to allow maximum deposition of the medicament particles into the user's lungs, before discharge of the product from the pressurised dispensing container. Preferably the air flow controller comprises a portion contactable with a front end of the pressurised dispensing container. An advantage of the present invention is that the operation of the air flow controller is effected by contact of the front end of the pressurised dispensing container with the air flow controller. It has been found that the variation in height of pressurised dispensing containers, taken from the tip of the valve stem to the base of the container, can vary by several millimetres. An advantage of the present invention is that such a variation in the height of the pressurised dispensing container does not affect the operation of the air flow controller and the timing of the discharge of the product with the establishment of the second air flow since the air flow controller is driven from the front end of the pressurised dispensing container. In a first embodiment the air flow controller comprises an annular membrane comprising one or more raised ribs on the upper surface of the annular membrane for contacting in use a front end of the pressurised dispensing container, and an outer circumference, engaging the housing to allow no or a minimum flow of air therebetween; the outer circumference being responsive to movement of the raised ribs to move out of engagement with the housing to allow the maximum air flow to pass therebetween. An advantage of the first embodiment is that assembly of the apparatus is straightforward and operation of the apparatus is not dependent on the variation in height of the pressurised dispensing container. A further benefit is that the air flow controller is concealed from the user and is thus less likely to be damaged. Preferably the raised ribs are raised radial ribs extending substantially from a central portion of the annular membrane substantially to the outer circumference . Alternatively the raised ribs are one or more raised, concentric circular ribs spaced radially from a central portion of the annular membrane substantially to the outer circumference. In a second embodiment the air flow controller comprises a generally cylindrical sleeve nestible within the housing, the sleeve being open at an upper end for receiving the pressurised dispensing container and having at a lower end a transverse membrane, a first segment of the transverse membrane comprising a first portion of the air flow controller contactable with the front end of the pressurised dispensing container and movable therewith, and a second segment of the transverse membrane comprising a second portion of the air flow controller, said second segment engaging with the first segment with the air flow controller in the first position to allow no or a minimum flow of air therebetween; deflection of the first segment relative to the second segment allowing the maximum air flow to pass through slits so formed between the first and second segments of the transverse membrane. An advantage of the second embodiment is that the assembly of the apparatus is straightforward and the operation of the apparatus is not dependent on the variation in height of the pressurised dispensing container. In a third embodiment the air flow controller comprises a plunger valve having an actuator biased into an extended position, said actuator contactable with a front end of the pressurised dispensing container and movable therewith; downward deflection of the actuator opening the plunger valve and allowing the maximum air flow to be established therethrough. An advantage of this embodiment is that the second air inlet is not gradually opened, but allows the second air flow to be quickly established. A further advantage is that the operation of the apparatus is not dependent on the variation in height of the dispensing container and the assembly is hidden from the user and is, therefore, less likely to be damaged. Preferably the plunger valve comprises a dash-pot assembly for delaying the upward movement of the actuator after depression of the actuator, said dash- pot delaying closure of the plunger valve. An advantage of using a dash-pot assembly is that the closure of the second air inlet can be delayed until some seconds after the user releases the pressurised dispensing container. This is advantageous in that it allows a user of the apparatus to continue to inhale the dispensed medicament even if they mistakenly release the pressurised dispensing container before stopping inhaling. This allows a greater proportion of medicament to be deposited in the user's lungs and helps to prevent incorrect operation of the apparatus. In a fourth embodiment the air flow controller comprises a skirt for attachment to a front end of the pressurised dispensing container, the skirt comprising one or more keys for engaging in one or more longitudinal grooves in the housing, and one or more downwardly extending flanges; said flanges comprising one or more raised protuberances for engaging apertures in a partition of the housing with the air flow controller in the first position; the partition separating the portion of the housing adapted to receive the pressurised dispensing container and the mouthpiece; downward movement of the skirt into the second position of the air flow controller causing the protuberances to unseal from the apertures to allow the maximum air flow to be established therethrough. An advantage of the fourth embodiment is that the air flow controller does not have to seal over a large surface area and thus a more reliable seal can be established. Preferably the minimum air flow is through a bleed hole. Preferably the apparatus also comprises a pressurised dispensing container. A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings of which: - Figure 1 is a sectional view of a first embodiment of the present invention; Figure 2 is an exploded perspective view of a first embodiment of the present invention; Figure 3 is a sectional view of a second embodiment of the present invention; Figure 4 is an exploded perspective view of a second embodiment of the present invention; Figure 5a is a sectional view of a third embodiment of the present invention; Figure 5b is a perspective view of a detail of the present invention; Figure 6 is an exploded perspective view of a third embodiment of the present invention; Figure 7a is a sectional view of a fourth embodiment of the present invention; Figure 7b is a perspective view of a detail of the present invention; Figure 8 is an exploded perspective view of a fourth embodiment of the present invention. Referring to Figures 1 and 2, a first embodiment of the present invention comprises an apparatus 1 comprising a housing 2 consisting of a cylindrical portion 6 open at its upper end to allow air into the apparatus 1 and to receive a cylindrical pressurised dispensing container 3, and a mouthpiece 7 projecting from the lower end of the cylindrical portion 6. The mouthpiece 7 may project laterally from the cylindrical portion 6 of the housing or may alternatively project from the cylindrical portion 6 at a slight downward angle. With the container 3 inserted in the cylindrical portion 6, there is a gap 5 between the container 3 and the inside surface of the cylindrical portion 6 adequate to allow air flow therethrough . The housing 2 also comprises a stem block 8, adapted to receive a valve stem 9 of the pressurised dispensing container 3. The stem block 8 is of conventional design and includes a bore communicating via a duct with an opening in the side wall of the stem block to direct an aerosol spray on discharge through the valve stem in a direction towards an outlet 11 of the mouthpiece 7. An annular membrane 12 is sealingly engaged with the uppermost end of the stem block 8. The annular membrane 12 is generally planar in cross-section and comprises a central bore 13. Preferably the cross- sectional shape of the central bore 13 is the same as the cross-sectional shape of the stem block 8. During assembly of the apparatus 1 the annular membrane 12 is sealingly engaged with the stem block 8 by forcing the stem block 8 partially or completely through the central bore 13. The annular membrane 12 is held in position by the outer diameter of the stem block 8 and the internal diameter of the central bore 13 of the annular membrane 12 being an interference fit. The diameter of the annular membrane 12 is such that the outer circumference 18 of the membrane 12 in a first position engages the internal surface of the cylindrical portion 6 of the housing 2 due to an interference fit. Thus the annular membrane 12 acts to block substantially the passage of air from the cylindrical portion 6 of the housing 2 into the mouthpiece 7. A bleed hole may be provided in the annular membrane 12 to allow a minimum air flow to pass from the open end of the housing 2 to the mouthpiece 7. Alternatively the seal between the annular membrane 12 and the housing 2 may be designed to allow a minimum flow of air therethrough. The annular membrane 12 together with the internal surface of the housing 2 acts as an air flow controller controlling the timing and flow of air through the inhaler apparatus 1. The membrane 12 may be manufactured from polypropylene or a soft elastomer which has good sealing properties. The annular membrane 12 further comprises a number of raised ribs 14 on the upper surface of the annular membrane 12. The radial ribs 14 act as a means of flexing the membrane 12 in use of the apparatus 1 into a second position and also to provide structural strength to the membrane 12 in the sealed position. The raised ribs 14 may be radial or can alternatively be concentric circles. The shape of the raised ribs 14 may be triangular in elevation and have an apex 15 positioned towards the central bore 13 to contact in use a front end 16 of the pressurised dispensing container 3. The ribs 14 may have a different shape without effecting the operation of the air flow controller. The front end 16 of the pressurised dispensing container 3 includes the ferrule and other surfaces of the pressurised dispensing container 3 at the end of the pressurised dispensing container 3 nearest the valve stem 9. If concentric circular ribs are employed, the ribs nearest the central bore 13 would be more raised than the ribs nearest the outer circumference 18. In use a user places the mouthpiece 7 in his mouth and inhales. With the annular membrane 12 in the first position engages with the housing 2 no substantial air flow past the air flow controller is possible. The user then depresses the pressurised dispensing container 3. The downward movement of the container 3 brings the front end 16 of the container 3 into contact with the apex 15 of the raised ribs 14 as the valve stem 9 begins to slide. Further downward deflection of the pressurised container 3 causes the raised ribs 14 to flex the annular membrane 12 from the first position to a second position. Since the central portion of the annular membrane 12 is sealingly fixed to the uppermost end of the stem block 8, the central region of the annular membrane 12 flexes less than an outer circumferential portion 17 of the annular membrane 12. The flexing of the membrane 12 causes the outer circumference 18 to unseal from the internal diameter of the cylindrical portion 6 of the housing 2 as the outer circumference 18 moves downwardly allowing air to flow from the open upper end of the housing 2 through the gap 5, between the outer circumference 18 and the housing 2 into the mouthpiece 7 and out of the outlet 11. Further depression of the dispensing container 3 further depresses the valve stem 9, flexes the membrane 12 to a third position and causes a dose of medicament to be discharged through the valve stem 9 and the valve stem block 8. The dispensing container 3 may be movable beyond the third position but this does not effect the operation of the apparatus 1. The medicament is discharged after the flow of air through the inhaler has been established and the particles of medicament are thus entrained in the flow of air and inhaled. It should be realised that in this embodiment, and in embodiments described later, the stroke of the valve stem 9 required to actuate the pressurised dispensing container 3 must be long enough to allow the air flow controller to move from the first position to the third position before the pressurised dispensing container 3 discharges a dose of medicament. It is to be desired that in the first position with the annular membrane 12 sealing against the internal surface of the cylindrical portion 6 that there is a minimum flow rate of air through the inhaler into the user's mouth when suction is applied to the mouthpiece 7. This minimum flow of air helps to prevent any sense of panic which may occur if the user of the inhaler was not able to inhale a quantity of air. Such a minimum volume flow rate of air may be produced by incorporating a bleed hole in the annular membrane 12. Alternatively, the minimum volume flow rate of air may be ensured by designing the annular membrane 12 to have a minimum leakage of air past the outer circumference 18 whilst in the sealing state. Thus, the inhaler has a minimum volume flow rate of air through the inhaler in the non-actuation state (with the membrane 12 in the first position) and a maximum volume flow rate of air through the inhaler when the annular membrane 12 has been flexed into the second position. The ratio of the maximum to minimum volume flow rates may be varied greatly, and may be easily adjusted by altering the size of the bleed hole and/or the nature of the sealing contact of the annular membrane 12. Preferably, the ratio of the maximum to minimum volume flow rates of air lies in the range of 8 to 12 and preferably the ratio of maximum to minimum volume flow rates of air is approximately 10. Further embodiments of the present invention will now be described. Features of the further embodiments common with the first embodiment have been designated with like reference numerals. In a second embodiment of the present invention, as shown in Figures 3 and 4, the air flow controller 20 comprises a flexible member 21 comprising a cylindrical sleeve 22 open at its upper end for receiving the pressurised dispensing container 3 and closed at its lower end by a transverse membrane 23. The cylindrical sleeve 22 is sealingly attached at its uppermost end to the housing 2. Preferably, this seal is made at the uppermost end of the cylindrical portion 6. However the seal can be made at any point of the cylindrical portion 6 of the housing 2 above the level of the transverse membrane 23. The transverse membrane 23 comprises a central bore 13 through which the valve stem 9 of the dispensing container 3 passes upon insertion of the dispensing container 3 into the apparatus 1. The transverse membrane 23 further comprises a first segment 25 coupled to a ring member 26 surrounding the central bore 13 and a second segment 27 separated from the first segment 25 by a number of slits 28 in the transverse membrane 23. In the non-actuation position the first and second segments 25, 27 engage with one another to prevent any substantial flow of air across the transverse membrane 23. Upon depression of the dispensing container 3, the front end 16 of the dispensing container 3 contacts the ring member 26 and causes the ring member 26 and the first segment 25 to deflect downwardly from a first to a second position. The second segment 27 of the transverse membrane 23 is separate from the first segment 25 therefore, when the first segment 25 and ring member 26 are deflected downwardly into the second position the slits 28 open allowing the passage of a maximum flow of air through the slits 28 when a user applies suction to the mouthpiece 7. Further depression of the dispensing container 3 further depresses the valve stem 9, flexes the transverse membrane 23 to a third position and causes a dose of medicament to be discharged through the valve stem 9 and the valve stem block 8. The medicament is discharged after the maximum flow of air through the inhaler has been established and the particles of medicament are thus entrained in the flow of air and inhaled. Preferably, the transverse membrane 23 in the first position has an upwardly extending domed configuration. This configuration biases the transverse membrane 23 into contact with the front face 16 of the dispensing container 3. This biasing action also ensures that the slits 28 re-close upon release of the dispensing container 3. Preferably the flexible member 21 is manufactured from a polymer such as polypropylene. A bleed hole may be provided in the first segment 25 or second segment 27 or, alternatively, the interface between the first and second segments 25, 27 can be designed to allow a minimum volume of air flow rate therethrough. A third embodiment of the present invention is shown in Figures 5a, 5b and 6. A plunger valve 30 of conventional design is provided adjacent the stem block 8. The plunger valve 30 comprises an actuator 31 extending upwardly from the plunger valve 30 towards the front face 16 of the dispensing container 3. In the first position of the plunger valve 30, the actuator 31 is biased into the upwardly extended position. The housing 2 further comprises a partition 32 at the lowermost end of the cylindrical portion 6, sealing the cylindrical portion 6 from the mouthpiece 7. In use, when a user applies suction to the mouthpiece 7 depression of the dispensing container 3 causes the actuator rod 31 of the plunger valve 30 to be depressed by the front face 16, from a first position to a second position opening the plunger valve 30 and allowing a maximum flow of air to flow from the open upper end of the housing 2 through the plunger valve 30, through the slots 33 on either side of the stem block 8 and into the mouthpiece 7. Further depression of the dispensing container 3 further depresses the plunger valve 30 to a third position and causes a dose of medicament to be discharged through the valve stem 9 and the valve stem block 8. The medicament is discharged after the maximum flow of air through the inhaler has been established and the particles of medicament are thus entrained in the flow of air and inhaled. The plunger valve 30 may be non-conventional and comprise a dash pot assembly to delay the upward extension of the actuator 31 after depression of the actuator rod 31 by the dispensing container 3. In this way, the closure of the plunger valve 30 and cessation of the air flow can be delayed for a known period after release of the dispensing container 3. This is advantageous in that if a user of the inhalation apparatus mistakenly releases the dispensing container 3 before completing the inhalation cycle, the air flow through the inhalation apparatus is not stopped for several seconds, thereby allowing the user to finish inhaling the discharged medicament. A fourth embodiment of the invention is shown in Figures 7a, 7b and 8. A flexible skirt 40 is provided and adapted to receive the front end 16 of the dispensing container 3. The skirt 40 contains a central bore 13 through which the valve stem 9 protrudes and engages the valve stem block 8. The skirt 40 further comprises one or more keys 47 which are received in grooves 48 in the internal surface of the cylindrical portion 6. The keys 47 when engaged in the grooves 48 prevent the skirt 40 rotating. The skirt 40 further comprises a downwardly extending flange 42 having a protuberance 43 on one vertical surface. The protuberance 43 may be in the form of a raised bump. In a first position of the skirt 40, the protuberance 43 is sealingly engaged with an aperture 44 in a partition 50 of the housing 2. The partition 50 separates the mouthpiece 7 from the cylindrical portion 6. The skirt 40 may be manufactured from a polymer or other flexible material. In use, the dispensing container 3 is depressed causing the skirt 40 to move downwardly into a second position and the protuberance 43 to ride out of the aperture 44. This movement is accommodated by the flange 42 flexing away from the partition 50. The resulting gap between the protuberance 43 and the aperture 44 allows the passage of a maximum flow of air through the inhalation apparatus into the mouthpiece 7 when a user applies suction to the mouthpiece 7. Further depression of the dispensing container 3 moves the skirt 40 to a third position and causes a dose of medicament to be discharged through the valve stem 9 and the valve stem block 8. The medicament is discharged after the maximum flow of air through the inhaler has been established and the particles of medicament are thus entrained in the flow of air and inhaled. A retaining restriction 49 is provided on the internal surface of the housing 2 above the level of the skirt 40. The retaining restriction 49 prevents the skirt 40 from being withdrawn from the housing 2 when the pressurised dispensing container 3 is removed to be cleaned or replaced. The force required to separate the skirt 40 from the front face 16 of the pressurised dispensing container 3 is less than the force required to move the skirt 40 past the retaining restriction 49. Bleed holes 45 may be provided in the skirt 40 to allow the passage of a minimum flow rate of air through the inhaler whilst the inhalation apparatus is in the rest position. It will be appreciated that various modifications to the construction of the apparatus 1 may be made without departing from the scope of the invention. An advantage of all these embodiments is that the air flow controller contacts in use a front face 16 of the pressurised dispensing container 3. The operation of the inhaler is therefore not dependant on the variation in height of the body of the dispensing container, which has been found to vary by up to an amount of the same order as the stroke length of the valve stem 9, but instead is dependant on the distance between the tip of the valve stem 9 and the front face 16 of the container 3, which has been found to have much less variation than the variation in height of the overall container 3. The timing of the dispensing of the dose of medicament in relation to the start of the maximum air flow is thus much more reliable. The timing of the discharge of the container 3 can be easily varied in relation to the start of the maximum air flow by altering the distance between the front face 16 of the container 3 and the air flow controller. A larger gap will result in a longer delay between the start of the maximum air flow and the discharge of the dose. Preferably the front face 16 of the container 3 is positioned in the rest state in contact with the air flow controller so that the maximum air flow starts as soon as the air flow controller begins to move from the first position to the second position.

Claims: C AIMS.: - 1. An inhalation apparatus for dispensing a product comprising a housing for a pressurised dispensing container and including a portion adapted to receive a valve stem of the pressurised dispensing container, an air inlet to said housing and a mouthpiece, said apparatus further comprising duct means communicating with the housing for conveyance of product towards the mouthpiece, and an air flow controller adjacent to the valve stem receiving portion, said air flow controller being biased to a first position corresponding to no or a minimum flow of air from the air inlet to the mouthpiece, and being movable in use by the pressurised dispensing container to a second position corresponding to a maximum flow of air from the air inlet to the mouthpiece, continued movement of the pressurised dispensing container causing a dose of product to be dispensed into the maximum air flow, the air flow being created by a user applying suction to the mouthpiece. 2. An inhalation apparatus as claimed in claim 1, wherein the volume flow rate of the minimum air flow is smaller than the volume flow rate of the maximum air flow. 3. An inhalation apparatus as claimed in claim 2, wherein the maximum volume flow rate is between 8 and 12 times the minimum volume flow rate. 4. An inhalation apparatus as claimed in any preceding claim, wherein the air flow controller comprises a portion contactable with a front end of the pressurised dispensing container. 5. An inhalation apparatus as claimed in any preceding claim, wherein the air flow controller comprises an annular membrane comprising one or more raised ribs on the upper surface of the annular membrane for contacting in use a front end of the pressurised dispensing container, and an outer circumference, engaging the housing to allow no or a minimum flow of air therebetween; the outer circumference being responsive to movement of the raised ribs to move out of engagement with the housing to allow the maximum air flow to pass therebetween. 6. An inhalation apparatus as claimed in claim 5, wherein the raised ribs are raised radial ribs extending substantially from a central portion of the annular membrane substantially to the outer circumference. 7. An inhalation apparatus as claimed in claim 5, wherein the raised ribs are one or more raised, concentric circular ribs spaced radially from a central portion of the annular membrane substantially to the outer circumference. 8. An inhalation apparatus as claimed in any of claims 1 to 4 , wherein the air flow controller comprises a generally cylindrical sleeve nestible within the housing, the sleeve being open at an upper end for receiving the pressurised dispensing container and having at a lower end a transverse membrane, a first segment of the transverse membrane comprising a first portion of the air flow controller contactable with the front end of the pressurised dispensing container and movable therewith, and a second segment of the transverse membrane comprising a second portion of the air flow controller, said second segment engaging with the first segment with the air flow controller in the first position to allow no or a minimum flow of air therebetween; deflection of the first segment relative to the second segment allowing the maximum air flow to pass through slits so formed between the first and second segments of the transverse membrane. 9. An inhalation apparatus as claimed in any of claims 1 to 4 , wherein the air flow controller comprises a plunger valve having an actuator biased into an extended position, said actuator contactable with a front end of the pressurised dispensing container and movable therewith; downward deflection of the actuator opening the plunger valve and allowing the maximum air flow to be established therethrough. 10. An inhalation apparatus as claimed in claim 9, wherein the plunger valve comprises a dash-pot assembly for delaying the upward movement of the actuator after depression of the actuator, said dash- pot delaying closure of the plunger valve. 11. An inhalation apparatus as claimed in any of claims 1 to 4 , wherein the air flow controller comprises a skirt for attachment to a front end of the pressurised dispensing container, the skirt comprising one or more keys for engaging in one or more longitudinal grooves in the housing, and one or more downwardly extending flanges; said flanges comprising one or more raised protuberances for engaging apertures in a partition of the housing with the air flow controller in the first position; the partition separating the portion of the housing adapted to receive the pressurised dispensing container and the mouthpiece; downward movement of the skirt into the second position of the air flow controller causing the protuberances to unseal from the apertures to allow the maximum air flow to be established therethrough. 12. An inhalation apparatus as claimed in any preceding claim, wherein the minimum air flow is through a bleed hole. 13. An inhalation apparatus as claimed in any preceding claim also comprising a pressurised dispensing container. 14. An inhalation apparatus substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

Inventors: DURKIN JASON R, PHILLIPS ANGELA S, DURKIN, JASON, R., PHILLIPS, ANGELA, S.
Applicants: BESPAK PLC, DURKIN JASON R, PHILLIPS ANGELA S, DURKIN, JASON, R., PHILLIPS, ANGELA, S.
Application year: 1998
Main classification: A61M15
IPC codes: A61M15