CA2106985C - Equipment for manufacturing of subcutaneous capsules - Google Patents

Abstract

The invention relates to an equipment for manufacturing subcutaneous capsules. The cap-sules are produced by cutting from a silicone tube lengths in excess of the final capsule length. The lengths are arranged into rows including a defined number of them and in these rows they are filled and sealed. One end of the capsules is first sealed by glue dosaged into their openings. The material for the capsules is dosaged by an aperture disc glid-able on a plane surface. By sweeping the upper sur-face of the disc the dosage volume is limited to the volume defined by the aperture. To regulate the packaging density of the material vibration may be used during the filling of the apertures. The do-saged material is conveyed to the capsule via a feeder funnel, through which a rotatable spiral spring, functioning as a filling screw, is inserted in-to the capsule to be filled.

Description

2~ g5 PCr~F~91~00090 Equipment for manufacturing of subcutaneous capsules The present invention relates to an e~auipment for manu-facturing of capsules filled with a medical substance essentially in powder form, which ~Arcl~lPc are intended to be implanted under the skin and from which the medical substance will diffuse lnto the blood circulation through the wall material of the capsules. Intended uses are i . a dosage of hormones, PcpP~ 1 y contraceptive h~ ~nPc as well as of antabus agents.
A problem in the dosage of contraceptive hoL ^~ has been above all the small amount of hormone substance to be portioned accurately in powder form dosages into the smallsized capsules. The amount of substance diffusing from the capsule is proportional to the amount of sub-stance in the capsule and therefore, to assure a correct and in all cases a truly predictable liberation, the capsules should include exactly the same amount of subs-tance. In the said h~ -7 use, the tolerance's allowed are ~ 596, which accuracy is extremely difficult to reach with the prior used manual dosing. The manual doslng method is, naturally, also a very expensive stage in th~
pIoduction of the capsules because of the great need of huma n work f orce .
The invention relates to providing a totally automatic manufacturing process for subcutaneous capsules filled with a medical :~ub~Lallc~, whereby the uniformity of the end result is essentially better than that of correspond-ing prior art processes, lnvolving partly manual stages.
In capsule production the starting point is a tube for forming the casing of the capsule, and for which a suit-able material is a c~ 1 ~ r~nP plastic . The diameter of the tube for manufacturing of hormone capsules is l . 5 mm. The tube is fed to the capsule manufacturing line as con-WO92/17148 ,,~ 35~ PCI/F191/000911 tinuous lengths from a suitable apparatus. At the star-ting point of the capsule manufacturing line, the tube is cut into capsule blanks o~ a suitable length, e. g . to lengths of about 34 mm.

The said blanks are then arranged into a row formed by several blanks. One row may comprise e.g. 12 blanks. The position of the blanks is fidv.lnt 3eo~cly chosen in con-formity with the h~nfll in~ positions of the tube in the prPc~P~in3 cutting device. One of such rows is advanta-geously joined together and it will then form a hfln~l in~
unit for the next process stages. In order to assemble this h~n~l ~n~ unit row it is posC~h1e to use a means to keep the blanks in their prescribed positions and with the help of which the h;~n-ll i n~ unit row is transferred from one stzge to another ln the process, as well as positioned for each process stage. The said means can 2dvantageously be a cassette of a clamping claw structure where the claws are in a mutual spring loaded clamping contact and where mutually co-operating indent2tion slots have been formed on the contact faces oi the claws ~n order to form through holes for receiving the capsule blanks . The claws are made to retract f rom each other against the said spring load to receiv~ the capsule ~5 bl~nks. The operation of the said cassette is advanta-geously synchronized with the capsule blank cutt~ng devi-ce.
To make the capsule blank fillable, one of its ends has to be sealed. In the apparatus according to the applica-tion, this stage is carried out so that one end of the tubes forming the capsule blanks receives a small amount of glue, e.g. a silicone glue, that adheres well to the tube material forming the capsule wall. The glueing is carried out by using a very thin nozzle needle inserted to a depth of about l. 6 mm in the capsule blank . The glue is discharged from the nozzle simultaneuously when the _ _ _ _ _ _ WO 92/t7148 ~ 1 0 ~ PCrJFI9lJD0091~
nozzle needle is rotated and extracted. By ad~usting the speed by which the nozzle needle is extracted it is pos-sible to regulate the amount of glue remaining in the capsule blank. This possibility is utilized in the pro-cess A~rr~rCl 1 ng to the application to eliminate the im-pncts of the viscosity fluctuations of the glue, by moni-toring the load on the glue pump and regulating the speed by which the nozzle needle is extracted in relation to the load. A high viscosity glue, discharged slowly from the needle, will load the dosing pump more than a low viscosity glue. Whenever the load on the dosiny pump is rising, the speed by which the needle is extracted is slowed down.
The glue fed to the end of the capsule blank is hardened by a suitable accelerator, e.g. using humidity or heat-ing. After the hardening of the glue there is the possi-bility, whenever desired, to use a finishing treatment of the sealed end by cutting out a part of the end of the capsule blank, from the area sealed by glueing. After sealing the capsule blanks, the blank row is turned so that the ends still left open are facing upwards. In this position the capsule blanks are forwarded to the filling stage .
The filling stage invplves as an essentlal element the dosing of the mass of material to be fed into the capsu-le blank. In the process according to the application, a device is used in which the dosing is based on a disc glidable along a plane surface and having through apertu-res determining the dose quantities. The material to be dosed is fed to the apel Lu~s closed by the lower plane surface, and the correct quantity is fin~l i7c~rl by sweep-ing any extra material away at the respective apertures to the upper surface level of the disc. The quantities thus dosed are delivered, individually to each capsule blank, by moving the disc along the plane surface to such _ _ _ _ , . .... . . , _ WO 92/17148 Pcr/FI91/0009n 2~ o~g35: 4 ~
a position where the lower surfaces of the apertures will be f reed In the process according to the application the doseo quantity of materlal are dropped from each aperture to its respective transportation groove made in the surface of a disc, operating as a vibrating Cu~lv~:yul. When the a~eL LUL~:~ are emptied the dosing disc is transferred back to its filling position. The dosed material quantlties proceed in the grooves of the vibrating .:u,-v~y~ further to feeding funnels under which the capsule blanks, car-ried by the clamping claw u~ssetL~:, have been conveyed.
In order to promote the flow of the material quantities into the capsule blanks, a special spiral f ~eder is used The said feeder comprises a spiral spring that has a diameter less than the inner diameter of the capsule blank, and a straight steering wire therein This spring is rotatable in the forward direction of its spiral.
2û As far as the feeding process itself is rnnf~prnpd~ the procedure is carried out so that the spiral spring is inserted into the capsule blank and made to rotate. Si-multaneously with the activation of the rotative movement the raising of the spiral spring from the capsule blank is initiated. When the rotation direction is as said above, the spring acts as a feeder screw. When the fill-ing of the capsule blank advances, the spiral spring ~is e~LLdu~d, still in rotation, from the capsule blank.
During the said operational stages the feeding funnels 3û are kept under vibration. When the head of the spiral spring has risen to the desired material filling level its rising r v. L is stopped, but vibration, and rota-tion of the spring are continued. Thus, the spiral spring determines the height of the material column fed to the capsule:
After the filling stage, it is advisable to clean the ;

WO 92/17148 2 ~ 8 ~ PCr/F191/00 l91 inner surfaces of the open ends of the capsule blanks to remove any adhered filling material to ensure the se~ling of the ends of the capsule blanks without problems. The ~1 e~n~ ns may be carried out on the inside of the mouth area of the capsule blank by uæing a scraping rotating mandrel or a ~LLr~ n~ brush. The ends of the capsule blanks are sealed by using similar ~L~,eduL~s as in con-nection with the above described closing of the f irst ends of the capsule blanks . Af ter the glue used in the sealing process has hardened, the capsule ends may be similarly finished by cutting parts away from their seal-ed portions.
After these stages the completed capsule~ are conveyed through as such known process stages, whereby the capsu-les are washed, dried, inspected, packaged and sterilized to ready-to-use products.
In the following, the invention will be described re~er-ring to the annexed drawing where:
Fig . l shows a f low chart of the process according to the application in principle;
Fig. 2 shows an ~mh~rlir-nt of an apparatus in princi-ple, for cutting the capsule blanks and their arran-gement in hAnrl 1 i n~ unit rows, Fig. 3 shows a dosing and filling apparatus seen in the forward direction of the process;
Fig. 4 shows a dosing and filling apparatus seen from above, r Fig. 5 shows a dosing and fiiling apparatus seen from the side with respect to the forward direction of the process;

WO 92/17148 21~ ~ 9 8 ~ pcr/Fls1/ooosn Fig . 6 shows a dosing and f illing apparatus axonomet -rically;
Fig. 7 shows a simplified flow chart according to Fig. 6, and Fig. 8 shows a magnified detail from the area of the feeding funnels.
-In the basic flow chart ~ccording to Fig. l the process stages are shown in the advancing order principally as described above.
The first stage of the process, i e. the cutting of the capsule blanks and their a~ lcln~ ~rt to rows forming the handling unit, is described in more detail in the draw-ing Fig. 2.
The silicone tube l forming the casing of the capsule blanks is fed as a continuous length from a coil, guided by two feeder rolls 2, to an aperture made in a disc 3 rotatable around a vertical axle. The aperture is a through hole and its diameter is clest3nPcl to match the outer diameter of the tube so that the cut tube stays in the aperture without any separate supporting means, part-ly due to the distortion tendency caused by the material memory of the tube. In connection with the tube feeding station there is a cutter device 4 by which the tube is cut to the upper surface level of the disc. The length of the capsule blank to be cut may be detPrmi nPd by the duration of the rotation movement of the feeder dlscs 2.
..
By rotating the disc around its vertical axle, it is possible to move the capsule blank, formed by the cut tube, to a discharge station where the capsule blank is taken from its aperture by a punch-through mandrel 5.
From the point-of-view of the flexible operation of the WO 92/17148 2 ~ ~ ~ 58 ~ PCr/Fl9l/00090 apparatus, it is advantageous to have several through apertures in the disc 3 whereby the cutting of a new blank and the discharging of the previous blank may be carried out as simultaneous operations.

The operation of the cutting device is advantageously ~y~ u--ized with the device arranging the cut capsule blanks. As such a device arranging the capsule blanks it is advantageous to use a spring-loaded l ~rin~ claw cassette 6 consisting of two opposite co-operating halves 6 ' and 6 ' ' . The halves are separated from each other by a vertical dividing plane, the separating surfaces being furnished with essentially semi-circular opposite Qrooves traversing the dividing plane, that, when operating to-gether, form the through apertures 8 receiving the capsu-le blanks 7. The apertures 8 have been placed at an even distance from each other, and the clamping claw cassette 6 has been arranged to be moved stepwise with steps of respective length in the direction of the row of apertu-res to receive the capsule blanks 7 coming from the cut-ting device.
To facilitate the reception of individual capsule blanks 7 from the cutting device, the clamping claw cassette 6 ~ has been arranged to be opened, to a limited extent, for each receiving operation. This opening capability has been provided by two wedges 9, actin3 in the division plane at the ends of the cassette, which wedges can be pushed towards each other in the division plane.
By means of these wedges, the clamping claw cassette 6 ha~ves, may be retracted f rom each other against the springloaded (not shown) force pressing them against each other. The springload may be provided for, e . g . in con-nection with screw joints ~oining the clamping claw cas-sette halves, by spring washers or similar devices, as the opening movement does not need to be very big in WO 92/1714~ 210 6 9 ~ ~ PCI /FI91/00090 relation to the diameter of the capsule blank.
Deviating from the embodiment shown in the drawing figu-res 1 and 2, the disc 3 of the cutting device may also be arr2nged to rotate around a horizontal axle and, respec-tively, the rl 2 , in9 claw cassette 6 arranged to receive the cut capsule blanks in horizontal positions.
The capsule blanks are conveyed, carried by the said rl 1 1 nr claw cas2,et ~ 6, to the next processing stages and through them, of which a general description concern-ing the sealing of the second ends and their trimming has been given above. These operati~ons may be carried out_ when the capsule blanks are either in a vertical positi-on, as shown in Fig. 1, or alternatively, in a horizontal position. An alternative trimming of the ends may also be 'in~l with the trimming following the sealing of the filling end, to be ti~crr~h~A later, to a single stage only .
As an important partial staç,2e in the process, the dosing of the material to be packaged into the capsules is de-scribed, as well as the equipment relating thereto, re-ferring to the drawing figures 3 to 8. The said equipment is used to dosage the material for each capsule blank and to direct it to the respective capsule along its own pzth .
The dosing eguipment is based on the so-called aperture disc tPrhnrlogy, whereby the material mass is dosed by the means of a plate of even thickness movable on a plane surface and provided with through apertures defining the dosage quantities. When the dosage guantities are meter-ed, the disc rests on the said plane surf ace and the plane surface closes the bottom part of the apertures_ The material to be dosed is made to f low into the apertu-res and the exact quantity is ~etermined by sweeping ~ he WO92/17148 21~ 5 PCr~F191~00090 excessively fed heap of material away, to the upper sur-face level of the disc. Then the disc is moved along the said plane surface to a discharging station, where the lower surface of the apertures is opened to a receptacle for the material.
In the device according to Fig . 3, the material used f or filling the dosage aye, ~u~s is fed from a storage con-tainer 10 by means of a compartment feeder 11, performing a rough dosing, to a trough-like vibrating conv yu~ 12.
This vibrating Cullv-:yul ~L~Insrels the material to be dosed further to a distribution through 13 at a lower le-vel, the open lower part of which is def ined by the dosing disc 14. The dosing disc 14 is glidable on the plane surf2ce 15. The number of through apertures in the dosing disc 14 in the described embodiment is half of that of the capsule blanks to be filled in the clamping claw cassette 6. The parts of the device may naturally also be tli~ nP~ so that the number of the apertures and the number of the capsule blanks to be filled are the same. The diameter of the apertures 16 is dimensioned so, taking the thickness of the aperture disc 14 into ac-count, that the apertures, when filled up to the upper surface level of the disc, will define the volume of the dose intended for each capsule, or so that a dosage volu-me is formed by a multiple of aperture fillings.
In the device described in the drawing f igures 3, 4, and 5 the material to be dosed and transported by the vibrat-ing uu--v~yu~ 12 is spread in the distribution through 13 by means of 2 device movable by a cylinder-piston device 18. An optical control device 19 is 2rr2nged in connec-tion with the through by means of which the surf ace level in the distribution through 13 of the material to be dosed is monitored, and on the basis of the information of which the number of the operation cycles of the com-partment feeder 11, which functions as a rough dosing -WO 92/17148 PCr/FI91/0009(~
~ , . . .
21~9~5 lo ~
device ~ is determine The plane surface 15, on which the dosing aperture disc 14 is glidable and upon which it rests duriny filling o~i the dosing apertures, is ~ ~ inPd with a suitable vib-rating device in order to direct a vibrating effect on the plane surface during the filling stage Of the apertu-res 16. ThiS vibrating effect Will act on the r;~rk~gi n~
density of the material to be f illed lnto the dosing 0 c-~eL~ult:s 16. It is possihle to regulate the packaging degree by regulating the duration and/or the intensity of the vibration. Another fector infl~nr~nr the packaging degree is the filling level in the distribution through 3 of the material to be filled monitored by the said optical control device 19 After filling of the apertures, the dosing disc 14 is pushed along the plane surface 15 to the discharge sta-tion of the apertures. The upper surface of the dosing disc 14 is in gliding contact with the lower surface of the distribution through 13 whereby the lower edge of the through levels the dose volumes in the apertures to the upper surface leYel of the dosing disc 14, whereby the excess material remains in the distribution through 13 closed by the dosing disc 14.
In the level surface 15 there is formed a row of dischar-ge apertures 20 corrF~srnn~in~ to the dosing apertures 16, above which row the apertures 16 are glided. Arranged below the discharging apertures 20, there is a vibrating ~Gnv~y~ formed by a groove disc 21. In the groove disc 21 there is the same number of grooves 22 as there are discharging apertures 20, and the grooves and the dis-charging apertures are aligned so that the material in the dosing apertures can be discharged through the dis-charging apertures 20 to their respective groove 22 in the ~roove di c 21 The ~roove di_c 21 is pref~

4~ ~ I Q ~ ~ 8 ~ PCr/F19~ ~0009h 1 i ni n~ and equipped w$th a vibration device, whereby 2 groove 22 forms a ~:O~V~yul for a single dosage.
The dosaged material is transferred on the groove disc 21 to fill$ng funnels 23 arranged in a transverse row be-neath the fail edge of the groove disc 21. Below these filling funnels there has in turn been transferred a row of capsule blanks 7 carried by the t~lr, in~ claw cassette 6, the lower ends of the c~psule blanks having been seal-ed and advantageously trimmed according to the measures described above.
The equipment according to the figures 3 to 8 also comp-rises a filling apparatus 24, comprising a number of feeding devices corresponding to the number of filling funnels 23. Each feeding device comprises a rotating motor 25, a spindle 26, and a feeder screw 27 attached to the the lower end of the spindle. To operate the feeder screw 27 within the conditions determined by the small .li -ionc of the capsules to be filled, the filling screw is formed by a thin spiral spring. For better cont-rol of the movements of the spiral spring, a thin straight guiding wire is placed inside the spring, extending substantially along the whole length of the spiral spring.
The feeder screw 27 formed by the spiral spring is di-rected through each feeding funnel 23 to the capsule blank below it and is made to rotate. The rotative move-ment is naturally chosen in the feeding direction of the spiral spring. The feeder screw rotating in the capsule blank feeds the material fed into the feeder funnel effi-ciently into the capsule blank. In order to avoid unne-cessary compacting of the material in the capsule blank, the feeder screw is raised as filling is advancing. After the dosed batch has been completely fed, the feeder screw is removed completely from the capsule blank, and the WO 92/17148 PCr/F191/00090 21(~gg~ 12 blanks are transferred to be sealed. Before sealing, it is possible to clean the inside of their mouth areas to remove any L~ ining filling material. Sealing is carrled out by glueing in the same way as the sealing of the $ opposite end of the blank before the filliny stage.
After sealing, the ends of the filled capsules can be trimmed by cutting. After trimming, the final capsules will be removed from their respective ~ ,rin~ claw cas-settes nfter which operation they will be processed indi-vidually according to prior technology fl~ sc~ee~l briefly above .

Claims (4)

Claims

1. Equipment for manufacturing a subcutaneous capsule filled with a medical substance, from a tube forming the capsule casing, comprising a cutting device for cutting the capsule blanks into fixed lenghts, a means for ar-ranging the capsule blanks cut from the tube in a paral-lel fashion to rows including a specific number of capsu-le blanks, the said arranging means including a clamping claw cassette means for holding the capsule blanks in the said row through the processing stages following the arranging stage, devices for dosing glue to one end of the capsule blanks, devices for hardening the glue, means for turning the cassette means so that the capsule banks carried thereby turn to a position with their open ends facing upwards, a dosing device, based on a dosing aper-ture disc glidable along a plane surface, for dosing the medical substance in individual quantities for each cap-sule, devices for feeding the individually dosed medicine quantities for a respective capsule blank to a feeder, a feeder including for each capsule blank, a rotatable spiral spring means to be inserted into the capsule blank and extracted therefrom, devices for dosing glue into the open ends of the capsule blanks, and means for hardening the glue.

2. Equipment according to the claim 1, wherein the devi-ces for dosing the glue to the ends of the capsule blanks to be sealed comprise a glue nozzle insertable into and extractable from a capsule blank, respectively, the rate of extraction of which can be regulated in order to regu-late the amount of glue remaining in the capsule blank.

3. Equipment according to the claim 2, wherein the ext-raction rate of the glue nozzle from a capsule blank is made directly dependent on the load current of the pump motor feeding glue.

4. Equipment according to the claim 1 comprising means for cutting the ends of the sealed capsules within the area sealed by the glue.