DISPEMSING APPARATUS
The invention relates to a dispensing apparatus for use in dispensing, in particular, controlled or scheduled drugs.
A dispensing apparatus, or package, typically comprises a metering valve, a canister in which the liquified propellant-product formulation is stored and an actuator which is used to operate the metering valve. The metering valve is received sealingly in an open end of the cannister. The actuator, which may be, for example, an actuator button or nozzle stem block, is fitted over a valve stem of the metering valve. The metering valve and canister form a pressurised dispensing container. The liquified propellant may be a hydro-carbon or chloro-fluorocarbon having sufficiently high vapour pressure at normal working temperatures to propel the product through a metering valve. The product may also comprise a soluble mix of propellant and medicament. Conventional metering valves for use in pressurised dispensing containers such as shown in Figure 1, comprise a valve stem 11 co-axially slidable within a valve member 12 defining an annular metering chamber 13. "Inner" and "outer" annular seals 18, 17 are operative between the valve stem and the valve member to seal the metering chamber therebetween. The valve stem is generally movable against the action of a spring 25 to a dispensing position, wherein the metering chamber is isolated from the container 9 and vented to atmosphere for the discharge of product.
The valve 10 is usually held in place with respect to the container by a closure 15 which is crimped to the container. The pressurised dispensing container is then inverted such that the valve stem of the metering valve is lowermost and actuated by depressing the 10
20
':> c.
30
35 valve stem relative to the pressurised dispensing container. The liquified propellant an suspended powdered medicament contained in the annular metering chamber is vented to atmosphere where . t is, for example, inhaled by the user. On rel se of the valve s em, the spring restore the val e t em to i s unact[upsilon] ted posi ion, whereby the annul .[iota]<'>-<">met ing chamber i s re-eharqe i Lh Liquif i ed r pej<">[iota] ant and suspended powdered medicament from trie v ] erne of l quifi ed pro[mu]ei ianr toreu n e : o^.-_, ..,;<-->i e dispens r:g cont i ner .
Typically, the container<L)>is me Lai can.; s ar eonvent lona pres urised [pi]isperic. re: ont:e[iota]ners have err.ain lii;; L r.iL. one when 1. '_ co:teS '. rii soensin[alpha] particula produc s su::; s control ie::i ;: scheduled drug;; . on entional pressurised di s eu<">e; [pi] ontainery can roe ea ily ;u;:iw user o [alpha]m c; r wi conte t of th cont iner.. Thi s car. i o :; t o unauthorised peo le access! nq the C;<'>;r: LJ .<'>.or contents . The pressurised iaper-sing contains r [iota]:\a y ;.[iota]i so nave a high ullage volume 6t as y<'>nown in lie., . The uilaqe 60 oi e centairier i that ve<'>! u:r<>of the product which cannot be readily dispens i because it lies below the level of the injet port ; of the valve body 1 . This represen s wasted product a r.d i s par icularly undesi able where the prn i;<->~. i expensi ve .
Another known variant, of pre.ssar 1 so ; di spensing container is sini lar to that shown in<>''! sure 1. However, the valve is operated i the upright position with the valve stem 11 pointing upwards. A dip-tube is provided to transfer .<'>liquid product from the container to the metering valve. A problem with this type of pressurised dispensing container is that the valve must be operated a rmmber of times in order to 'prime' the dip-tube and transfer the first dose of product to the metering valve. This can lead to ont:e[iota]ners rii soensin[alpha] scheduled [pi] ontainery
:; t o
.or contents .
;.[iota]i so nave a . The<>of the i because it ; of the valve a r.d i s<->~. i
; di spensing sure 1. uncertainty for the user as to when the dispensing container is ready for use . In practice the number of actuations specified by the manufacturer is overly conservative leading to loss of product . This is a particular problem where th product is expensive .
Another problem with the upright dispensing containers is that the metering valve is prone to ' loss of prime ' wherein the product contained in the metering chamber between actuations drains back into the container body.
The present invention seeks to overcome these problems .
Accordingly, the present invention provides dispensing apparatus comprising a glass bottle having an opening at one end closed by a metering valve, the container containing a formulation comprising HFA 134a or 227 and a medicament, the metering valve comprising a valve stem co-axially slidable within a valve body, the valve body being provided with one or more inlets communicating with the formulation, wherein in an operative position of the dispensing apparatus the valve stem of the metering valve is located lowermost with respect to the glass bott le such that the formulation covers the one or more inlets of the valve body.
A particular embodiment of the present invention will now be described by way of example only, with reference to the accompanying drawings , in which:
Figure 1 is a cross-sectional view of a known pressurised dispensing container; and
Figure 2 is a cross-sectional view of a pressurised dispensing container according to the present invention.
As shown in Figure 2 , a valve 10 of a dispensing apparatus according to the present invention includes a valve stem 1.1 which protrudes i.rort a n[alpha] is axially slidable within a valve member<">\ [lambda]<'>, tire valve member 12 and valve ste 11 defining therebetween an annular metering chamber 13. The val.ve member 12 is located within a valve body 14 which is positioned within a nec 31 of a glass bottle 30 containing a product to oe dispensed. The metering vaive 10 is held in position with respect to the glass bottl 30 by means el a terra. c 15 which is crimped to the top of the g i ass cccr . . aling between the valve body 1 [Lambda] and q:ass o :_ r<">: e 30 is provided by an annular gasket<'>. '--- . Toe t r ule 15 has an aperture 28 t rough which, one one \ - - tt the valve stem 11 pro rudes . 7he vu '. -...<->e noay 1 n t ; zed o be .:; close fit to the internal. u_e;tetor el : e neck 31 of the glass not.:. I c 30 so an -.. -.: ::.:r.1 rti.se : : . .<->:rap therebetween . I'hc V[upsilon].vo oooy .:. - an,:; :.<->:.. - t ; - are a ; o shaped so to be continuous ;;.::.<'>:<"->. etc ;t..n.;[iota]er<">with ar. annul r gap e :<[tau]>pre.Lorably to moio t nan -.,<->.<->: :: [iota]\ . "i'.h i results in a more:- stable s atinq of r.ht u_ve and a substantial reduction in the uilace vo[upsilon]tte 60 of the dispensing apparatus. Preferably, the e__age is less than 3% ol the container vc note . The ferrule closure 15 is preferably crimped n sucn a way as to make its removal dif f icul f. a d such : a \. re o ; arc; replacement of the ferrule d: woaio ne vi en from its external appe rance. [Lambda]l te me ivel y toe ferrule 15 may be permanently fixed to the class oottie 30 by means of, for exampl e, epoxy res : : . Tne ul ass bottle 30 ensures that any attempt to tamper with the container itself would lead to breakage n: the bottle. The result, is a dispensing apparatus which cannot easily be opened and the contents transferred or consume . A pair of seals 17, I[delta] of an elastomeric material extend radially between the valve stem 11 and the valve member 12. The "outer" seal 17 is radially compressed between the valve member 12, valve stem 11 and ferrule 15 so as to provide positive sealing contact to prevent leakage of the contents of the metering chamber 13 between the valve stem 11 and the aperture 28. The compression is achieved by using a seal which provides an interference fit on the valve stem 11 and/or by the crimping of the ferrule 15 onto the glass bottle 30 during assembly. The "inner" seal is located between valve member 12 and valve body 14 to seal an "inner" end of the metering chamber 13 from the bottle contents.
The end 19 of the valve stem 11 is the discharging end of the valve stem 11 and protrudes from the ferrule 15. The end 19 is a hollow tube, which is closed off by a first flange 20 which is located within the metering chamber 13. The hollow end 19 of the valve stem 11 includes a discharge port 21 extending radially through the side wall of valve stem 11. The valve stem 11 further has an intermediate section 22, extending between the first flange 20 and a second flange 26. The intermediate section 22 is also hollow between the flanges 20, 26 and defines a central passage. It also has a pair of spaced radial ports 23, 24 which are interconnected through the central passage. The second flange 26 separates the intermediate section 22 of the valve stem 11 and an inner end 27 of the valve stem 11.
A spring 25 extends between the second flange 26 and a shoulder defined by the valve body 14 to bias the valve stem 11 into a non-dispensing position in which the first flange 20 is held in sealing contact with the outer seal 17. The second flange 26 is located outside the metering chamber 13, but within the valve body 14. The metering chamber 13 is thus sealed from the atmosphere by the outer seal 17, and from the glass bottle 30 to which the valve 10 is attached by the inner seal 18. In the non-dispensi g position, radial ports 23, 24, together with the centr l cavity in the intermediate section 22 of the valve member II connect the metering chamber 13 with the valve body 14. Inlet ports 55, 56 connect the valve body 14 with the bottle
30 so that, in this non-dispensing condition, the metering chamber 13 will be charged with product to be dispensed. The valve body 14 is also provided with a filling hole 8. The metering v l e 10 arid glass bottle 30 together form the dispensing apparatus.
The meterinq valve may be onstru e 1 lorn^combination of thermopla ic, el asr omeri c, c: or ami c and metallic materials. i-'or exam le components such as the v l e body 1 , v 1 ve s t en 11 no m ter: j.nq engineer: 12 may be made of thermoplastic po mer c materials such pulyoxymoi hy 1 ene ( ace a<">.<'>: , p:h ybttyleiu; terephtha ! ate or polyarrd h ttict . doitocnents [Alpha]\: :r. as the ou r a no inne sea 1 1 , L<'>and the g s k t If, may be made of el stom r i c no 1 ymorio ;to or r l s such as ethyl, ene propyiene di ene, poly aery lour t r 1. le (n i t.r i l.e) or chloropreiie (neoprene; . Component s sticn as the valve stem II may be made oi ::e:.a:lio materials such. as st inless eel . Compone such s fine va 1 ve member 12 may be made of ceramic: materials such as g 1 a s s .
In use, the dispensing appar tus is inverted such that the valve stem 11 is lowermost, as shown in Figure 2, such that the liquified propellant in the glass bottle 30 col lects at the end oi<">the glass bottle 30 adjacent the metering valve l[upsilon] so as to cover inlet ports 55, 56. As a result no clip-tube or other transfer means is required. Consequently there is no wastage of product in priming the metering valve. The inverted dispensing apparatus also shows a reduced risk of 'loss of prime' when compared to an upright dispensing apparatus.
Upon depression of the valve stem 11 relative to the valve member 12 so that it moves inwardly into the bottle 30, the radial port 24 is closed off as it passes through the inner seal 18 thereby isolating the metering chamber 13 from the contents of the valve body 14 and glass bottle 30. Upon further movement of the valve stem 11 in the same direction to a dispensing position, the discharge port 21 passes through the outer seal 17 into communication with the metering chamber 13. In this dispensing position, the product in the metering chamber 13 is free to be discharged to the atmosphere via the discharge port 21 and the cavity in the hollow end 19 of the valve stem 11.
When the valve stem 11 is released, the biassing of the return spring 25 causes the valve stem 11 to return to its original position. As a result, product in the glass bottle 30 passes through inlet ports 55, 56 and filling hole 58 into valve body 14 and in turn from valve body 14 into the metering chamber 13 to recharge the chamber in readiness for further dispensing operations. Due to its relatively small diameter, little product enters the valve body 14 through vapour vent hole 58.
The dispensing apparatus of the present invention is primarily designed for the dispensing of formulations containing controlled or scheduled drugs in a liquified propellant such as HFA 134a or 227. Examples of such drugs are opiates (including morphine and fentanyl) , cannaboids and nicotine. However, the apparatus is suitable for dispensing other products which are typically expensive or where the risk of unauthorised access needs to be minimised.