CA2259404A1 - Metering and packaging device for dry powders - Google Patents
Metering and packaging device for dry powders Download PDFInfo
- Publication number
- CA2259404A1 CA2259404A1 CA002259404A CA2259404A CA2259404A1 CA 2259404 A1 CA2259404 A1 CA 2259404A1 CA 002259404 A CA002259404 A CA 002259404A CA 2259404 A CA2259404 A CA 2259404A CA 2259404 A1 CA2259404 A1 CA 2259404A1
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- CA
- Canada
- Prior art keywords
- powder
- charge
- area
- image
- carrier surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
- B65B1/00—Packaging fluent solid material, e.g. powders, granular or loose fibrous material, loose masses of small articles, in individual containers or receptacles, e.g. bags, sacks, boxes, cartons, cans, or jars
- B65B1/30—Devices or methods for controlling or determining the quantity or quality or the material fed or filled
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
- B65B1/00—Packaging fluent solid material, e.g. powders, granular or loose fibrous material, loose masses of small articles, in individual containers or receptacles, e.g. bags, sacks, boxes, cartons, cans, or jars
- B65B1/04—Methods of, or means for, filling the material into the containers or receptacles
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
- G03G15/04036—Details of illuminating systems, e.g. lamps, reflectors
- G03G15/04045—Details of illuminating systems, e.g. lamps, reflectors for exposing image information provided otherwise than by directly projecting the original image onto the photoconductive recording material, e.g. digital copiers
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
- G03G15/221—Machines other than electrographic copiers, e.g. electrophotographic cameras, electrostatic typewriters
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S141/00—Fluent material handling, with receiver or receiver coacting means
- Y10S141/01—Magnetic
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Quality & Reliability (AREA)
- Basic Packing Technique (AREA)
- Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
- Electrostatic Spraying Apparatus (AREA)
- Medical Preparation Storing Or Oral Administration Devices (AREA)
- Photoreceptors In Electrophotography (AREA)
- Dry Development In Electrophotography (AREA)
Abstract
Electrostatic phototechnology is used to meter and package microgram quantities of fine powders such as drugs. An electrostatic "image" (25A) having a given size and charge density is exposed to ionized drug powder (10) to attract a known precise amount of drug to the image. The resultant drug "image" (26A) is then transferred to a package (32).
Description
CA 022~9404 1999-01-04 W O 98/00337 PCT~US97/10494 METERnNG AND PACKAGnNG D~VICE FOR DRY POWDERS
2 The present invention relates to the packaging of dry powders and particularly 3 to the p~cl~ging of microgram quantities of powders for medical uses. In the4 metering and packaging of dry powders, particularly very small amounts of dry S powder medications, the drug industry has had difficulty with the packaging of 6 precise amounts of such powders. One of the reasons for this is that many powders 7 develop an electrical charge and the charge causes problems in measuring and8 packaging since powders tend to aggregate and stick to the sides of the containers and 9 metering devices. Thc present invention utilizes this ability of the powder to acquire an electrical charge for precisely measuring exact microgram quantities of the powder 11 and then placing these exact microgram ~uantities in individual containers.
12 In the past. technology has been used employing electrostatic charge to attract 13 a given quantity of powder to a surface. An example of this is the laser printer or the 14 electrostatic copy devices whel e a drun1 is charged and toner particles are attracted and held in position by the char~e. The charge on the drum is neutralized by the16 attracted toner powder. thus limiting the amount of toner in accordance with the 17 charge image on the drum. The charge on these printer drums is then transferred to a 18 sheet of paper or other carrier to give a final image.
19 In the present invention~ the same technology is employed for transferring a predetermined amount of a finely powdered medication to a carrier or an intermediate 21 such as a drum, carrying a charge of predetermined intensity and area. rotating the 22 charged drum surface. carrying the predetermined amoLlnt of powdered medication on 23 its surface. to a transfer station where the charge is overcome and the dry powder is 24 transferred to a package which is then sealed. In lieu of a drum, a belt, or other movable surface is charged to a given potential in a localized area.
26 When a given amount of a powdered dr~lg is to be packaged. the charge and 27 area of charge can be experimentally determined for each dose of drug and each 28 particle size distribution. This can be done by controlling either the charged area for a 29 given charge density or the total electrostatic charge on any individual charged area.
CA 022~9404 1999-01-04 WO 98/00337 PCTrUS97/10494 These conditions can be ad3usted to provide the desired amount of the particular drug 2 to be transferred at the transfer station.
3 Fig. I shows a schematic representation, of the attraction of negatively charged 4 powder particles to a support having a positive charge on the surface thereof.
Fig. 2 shows a block diagram of the various steps involved in practicing the 6 invention.
7 Fig. 3 is a schematic representation of one fonn of drum type electrostatic 8 device for transferring given small quantities of powdered drugs from an electrostatic 9 attraction station, where a given quantity of powdered drug is attracted to and neutralizes a given charge on the drum, and a subsequent transfer st~tion where the 11 drug is transferred from the drum to a package therefor.
12 Figs. 4 and 5 are schematic functional representations of preferred components 13 employed in the Fig. 3 type of apparatus.
~4 Fig. 6 shows a different system wherein separate carriers, having micronized drug particles electrostatically attached to their surface. are used to carry the drug to 16 the charged transfer surface.
17 Figs. 7 and 8 show methods of aerosolizing the powdered drug and ionizing 18 the drug to give it a specific charge.
19 Fig. 9 shows a graph illustrating the percentage of suspended particles as a function of time and size. permitting creation of a suspended particle stream of any 21 given desired size distribution.
22 Fig. 10 shows another embodiment of applying the aerosolized drug to a drum 23 carrying charge "image".
24 Fig. 11 illustrates an ion projection system for creating the chargc "image?~ on a dielectric surface.
26 Referring first to Fig. I there is illustrated a chamber 14 cont~inin~; aerosolized 27 dry powder particles 10. These particles l O are suspended in air and carry a charge, 28 for example a negative charge. Also in the chamber is a support surface 12 having a 29 charge opposite to that on the particles. The support surface 12 will attract a number of charged particles 10 sufficient to neutralize the charge on the surface of the support CA 022~9404 1999-01-04 O 98/00337 PCT~US97/10494 12. This support surface is one that can hold a discrete electrical charge on its surface, such as in~ tin~ material, e.g. plastic or a semiconductor material, such as selenium, 3 used in the photocopy industry.
4 The actual amount of powder transferred to the carrier sheet is a function of the mass to charge ratio of the powdercd particles. If one assumes surface charge 6 saturation, the amount of charge carried by the particles is directly related to the 7 surface area. For spheriodal particles~ the charge varies as the square of the radius and 8 the mass varies as the cubc. Thus, the amount of charged particles picked up by a 9 given portion of the surface of the chargc carrier will be a function the total charge on the carrier. Thus, with a given surface charge density on the carrier, the amount of 11 powder picked up is directly proportional to the charged area. Thus. for doubling the 12 amount of powder to be picked up, the area on which charge is placed can be doubled.
13 This can be used as a basic method to control the amount of powder to be picked by 14 the carrier. Thus, for any particular powder or particle size distribution of powder~ the exact area and amount of charge needed can be experimentally determined.
16 Referring now to Fig. >. there is a schematic flOw diagram of the various items 17 of equipment needed to perform in the total proeess from powder supply to a sealed 18 package conl~ining a specified amount of powder in the package. At 16 is indicated 19 the powder supply which is fed into a device 18 for creating an aerosol of the powder.
Next the powder particles are ionized at 20. As will be indicated later~ a number of 21 these steps and pieces of equipment can be combilled. At 24 is indicated a carrier 22 surface capable of m~int~ining a space charge on its surface. This can be a plastic 23 belt, for example, or a selenium drum of the type used in Xerox TM photocopiers. This 24 carrier surface 24 is passed tllrough a charging station . 5 where predetermined electrostatic charge 25A (an electrostatic ''image") is created on a predetermined area 26 of the transfer surface. This charged surface 25A then passes through a step 26 27 wherein powder 10 is deposited on the chalged carrier surface in a sufficient arnount 28 26A to neutralize the charge carried by the carrier surface. Thereafter. the carrier 29 surface, carrying the predetermilled amoullt 26A of powder on its surface. is passed to a powder discharging device 30 which discharges the powder 26A from the surface ~4 CA 022~9404 1999-01-04 W 098/00337 PCTrUS97/10494 onto a p~k~ging material 28? which may have indentations 29 for receiving the 2 powder. The packaging material 28 cont~ining its charge of powder 26A~ then passes 3 through a package sealing step 32.
4 As mentioned previously in discussing Fig. 1~ the carrier surface with the electrostatic charge carries a known amount of charge on its surface and the polarity 6 of this charge is opposite to that of the powder particles suspended in the chamber.
7 The charged particles migrate to the charged surface because of the attraction by the 8 opposite nature of the charges. This migration of the particles continues until the 9 charge on the carrier surface is neutralized.
The actual amount of powder mass transferred to the carrier surface is a 11 function of the mass to charge ratio of the charged particles. Although it is dif~lcult to 12 achieve a linear relationship between the mass and the actual charge~ it is possible to 13 establish a fixed relationship between the surface area of the powder particles and the 14 charge the powder particle is carrying at charge saturation. I~owever, the surface area of a mixed group of powder particles of difl'erent sizes and shapcs can be extremely 16 difficult to calculate m~them~tically~ particularly when the shapes are irregular~ (e.g.
17 non spherical, microcrystalline~ etc.) As mentioned earlier. the simplest method of 18 determining the amoullt and area of charge to attract a given weight of particles is to 19 estimate the correct area and charge and then apply the estimated charge to the estimated area on the carrier surface 24 and expose this selectively charged area to a 21 mass of powder which has been ionized in tlle ionizing step. The amount of powder 22 deposited can then be readily measured at the discharge step. Thereafter~ either the 23 size of the charged area or the arnount of cllarge applied to the area at the charging 24 station 25 can be adjusted upwardly or downwardly to provide the correct amount of charge, both in area and charge intensity~ for picking up a desired weight of oppositeiy 26 charged powder.
27 Referring now to Figs. 3, 4. and 5 olle preferred apparatus for accomplishing 28 the invention is illustrated schematically in Fig. 3~ with details of the components 29 thereof being shown in Figs. 4 and ~. The charge carrying surface is illustrated as a photo sensitive drum 24A which rotates between the charge "image" exposure 25 CA 022~9404 1999-01-04 O 98/00337 PCT~US97/10494 which creates a charge ~'image" 25A on the surface of the drum 24A. (see Fig. 4)2 This "image" exposure can be a light source e.ga laser beam (or other controllable 3 photon source). which is capable of creating an e}ectrostatic "image" 25A on the 4 surface of the drum of a desired size and charge density. The charge "irnage" 25A is S then rotated to the image development station containing a bulk drug reservoir 78 and 6 a high frequency vibrator 80 and an electrostatic defector 82 for producing an ioni~:ed 7 cloud of drug powder which is attracted to the charge "image" 25 to neutralize charge 8 in the "image"~ thus, forming a powder "image" 26A cont~inin~; a predetermined 9 arnount of powder. (see Figs. 4 and 5) This powder "image" 26A is rotated to a drug transfer station 30 where it is released into the pockets 29 in the packaging layer 28.
11 This transfer to the pockets 29 is accomplished. in one preferred embodiment, by the 12 use of high voltage plate 56 (see Fig. 5) which overcomes the attraction of the charged 13 "image" 25A on the sul-face of the drum~ thus releasing the powder "image" 26A into 14 the pocket 29. The pocket containin~ the predetermined quantity of drug is then passed through the sealing step 3~.
16 Fit!. 6 shows another embodiment of tlle.invention wherein the micronized 17 drug particles 10 are carl ied on the surface ~f discrete carriers 60 which can be small 18 plastic beads. for example. When these plastic beads are contacted with an image 19 25A, the micronized particles 10 are transferred to the charge "image" 25A on the surface of the drum 24A from the discrete carrier balls 60. To accomplish this~ the 21 positive charge on the ima~e ~5A should be lligher than the positive charge on the 22 surface of the individual carriers 60.
23 Figs. 7 and 8 show additional details of means for both handling drugs and 24 providing aerosolization and ionization to provide a suspended stream of ~me drug powders having a predetermined size and charge and for delivering same to a 26 meterin~ chamber 86. ~n Fig. 7 and 8. elements 16A. 18A and 20A and 16B. 18B and 27 20B correspond to the equivalent elements in Figs. 2~ 3 and 4.
28 Since repeatability is important for dru~ meterin~ it is necessary to effectively 29 address the issue of charge to mass variation with particle size.
CA 022~9404 1999-01-04 W 098/00337 PCT~US97/10494 One method of over-coming this problem is to control the particle size 2 distribution in the drug powder. Fig. 8 shows one implementation to achieve this 3 control of particle size. The voltage on the electrostatic deflector 82 is adiusted to 4 control the particle sizes to be suspended in the holding chamber for delivery to the ionization chamber. Once the desired particle sizes are suspended they are drawn into 6 the ionization charnber to ensure surface charge saturation on the,particles. This will 7 give a known charge to the mass ratio.
8 Fig. 7 shows an alternative means for controlling the size distribution. A high 9 velocity air stream 84 is used to deaggregate and aerosolize the powder. Thedeaggregated powder is then contained in holding chamber 18A. The purpose of the11 holding chamber is to allow the larger size particles to settle, thereby producing a 12 favorable particle size distribution. The particle size distribution is a function of the 13 holding time as shown in Fig. 9. The suspended particles are then ionized and 14 exposed to the charge image as shown in at 26 in Fig. 3 Fig. 9 shows the percentage of particles sizes suspendcd in a holding chamber 16 as a function of timc. Such a chamber may be provided with a slow upward flowing 17 air current to m~int~in the aerosol suspension. ~s can be seen. the percentage of 18 suspended particles is very largely determined by particle size (where S equals small 19 particle sizes, M equals medium particle sizes and L equals large particle sizes).
Through experiment one can select a time slot T that will give the desired particle size 21 distribution for any particle drug dosage. Additionally. or in place of settling time, 22 one or more filters can be used for obtaining a given particle size range.
23 Fig. 10 is similar to Figure 4 except that the Image Development Station 26 iri 24 this figure is replaced with the Sta~ionary electrode 26B and an air passageway 50 for carrying the aerosolized powder. The rotatin~g drum 24 has a dielectric or 26 photoreceptor surface on to which is deposited the latent image. As an example the 27 aerosolization chamber would be similar to that shown in Figure 7. The metering 28 chamber in Figure 7 is then the air-passageway 25 between the dielectric surface 24 29 and the stationary electrode 26B with a bias voltage V applied between surface 24 and electrode 26B. The undeposited powder then exits at the right sidc of this air-CA 022~9404 1999-01-04 W O 98/00337 PCTrUS97/10494 passageway to be collected for later use or recirculated back into the aerosolization 2 chamber.
3 Figure 11 above shows an ion projection print head where an ion beam is used 4 to produce a charge "image" on a dielectric surface. The corona wire 52 has a high S voltage applied to it which causes the air to breakdown and produces the ions 52A
6 necessary for the operation of the ion projection printers. The rem~in~ r of the ion 7 projection print head includes the usual control electrode 54~ screen electrode 56 and 8 insulator 58. The relative potential that is applied to the control and screen electrodes 9 then regulates the amount of ions 25C that will be metered and deposited on to the dielectric surface 24 these ions being deposited on the surface to form the latent image 11 25A. Both the intensity and size of the ion beam can be adjusted as will be apparent 12 to one of ordinary skill in the art. The advantage of this system is that it does not 13 require a photosensitive surface and can therefore be rugged making it suitable for the 14 manufacturing enviromnent.
The invention also may be advantageously employed for forming pills of 16 microgram quantities of a drug by printing on a substrate an "image" formed of 17 discrete dots of finely divided drug particles~ the quantity of particles in a dot 18 corresponding to a given quantity of drug, and packaging one or more of the dots as a 19 predetermined therapeutic drug dose.
12 In the past. technology has been used employing electrostatic charge to attract 13 a given quantity of powder to a surface. An example of this is the laser printer or the 14 electrostatic copy devices whel e a drun1 is charged and toner particles are attracted and held in position by the char~e. The charge on the drum is neutralized by the16 attracted toner powder. thus limiting the amount of toner in accordance with the 17 charge image on the drum. The charge on these printer drums is then transferred to a 18 sheet of paper or other carrier to give a final image.
19 In the present invention~ the same technology is employed for transferring a predetermined amount of a finely powdered medication to a carrier or an intermediate 21 such as a drum, carrying a charge of predetermined intensity and area. rotating the 22 charged drum surface. carrying the predetermined amoLlnt of powdered medication on 23 its surface. to a transfer station where the charge is overcome and the dry powder is 24 transferred to a package which is then sealed. In lieu of a drum, a belt, or other movable surface is charged to a given potential in a localized area.
26 When a given amount of a powdered dr~lg is to be packaged. the charge and 27 area of charge can be experimentally determined for each dose of drug and each 28 particle size distribution. This can be done by controlling either the charged area for a 29 given charge density or the total electrostatic charge on any individual charged area.
CA 022~9404 1999-01-04 WO 98/00337 PCTrUS97/10494 These conditions can be ad3usted to provide the desired amount of the particular drug 2 to be transferred at the transfer station.
3 Fig. I shows a schematic representation, of the attraction of negatively charged 4 powder particles to a support having a positive charge on the surface thereof.
Fig. 2 shows a block diagram of the various steps involved in practicing the 6 invention.
7 Fig. 3 is a schematic representation of one fonn of drum type electrostatic 8 device for transferring given small quantities of powdered drugs from an electrostatic 9 attraction station, where a given quantity of powdered drug is attracted to and neutralizes a given charge on the drum, and a subsequent transfer st~tion where the 11 drug is transferred from the drum to a package therefor.
12 Figs. 4 and 5 are schematic functional representations of preferred components 13 employed in the Fig. 3 type of apparatus.
~4 Fig. 6 shows a different system wherein separate carriers, having micronized drug particles electrostatically attached to their surface. are used to carry the drug to 16 the charged transfer surface.
17 Figs. 7 and 8 show methods of aerosolizing the powdered drug and ionizing 18 the drug to give it a specific charge.
19 Fig. 9 shows a graph illustrating the percentage of suspended particles as a function of time and size. permitting creation of a suspended particle stream of any 21 given desired size distribution.
22 Fig. 10 shows another embodiment of applying the aerosolized drug to a drum 23 carrying charge "image".
24 Fig. 11 illustrates an ion projection system for creating the chargc "image?~ on a dielectric surface.
26 Referring first to Fig. I there is illustrated a chamber 14 cont~inin~; aerosolized 27 dry powder particles 10. These particles l O are suspended in air and carry a charge, 28 for example a negative charge. Also in the chamber is a support surface 12 having a 29 charge opposite to that on the particles. The support surface 12 will attract a number of charged particles 10 sufficient to neutralize the charge on the surface of the support CA 022~9404 1999-01-04 O 98/00337 PCT~US97/10494 12. This support surface is one that can hold a discrete electrical charge on its surface, such as in~ tin~ material, e.g. plastic or a semiconductor material, such as selenium, 3 used in the photocopy industry.
4 The actual amount of powder transferred to the carrier sheet is a function of the mass to charge ratio of the powdercd particles. If one assumes surface charge 6 saturation, the amount of charge carried by the particles is directly related to the 7 surface area. For spheriodal particles~ the charge varies as the square of the radius and 8 the mass varies as the cubc. Thus, the amount of charged particles picked up by a 9 given portion of the surface of the chargc carrier will be a function the total charge on the carrier. Thus, with a given surface charge density on the carrier, the amount of 11 powder picked up is directly proportional to the charged area. Thus. for doubling the 12 amount of powder to be picked up, the area on which charge is placed can be doubled.
13 This can be used as a basic method to control the amount of powder to be picked by 14 the carrier. Thus, for any particular powder or particle size distribution of powder~ the exact area and amount of charge needed can be experimentally determined.
16 Referring now to Fig. >. there is a schematic flOw diagram of the various items 17 of equipment needed to perform in the total proeess from powder supply to a sealed 18 package conl~ining a specified amount of powder in the package. At 16 is indicated 19 the powder supply which is fed into a device 18 for creating an aerosol of the powder.
Next the powder particles are ionized at 20. As will be indicated later~ a number of 21 these steps and pieces of equipment can be combilled. At 24 is indicated a carrier 22 surface capable of m~int~ining a space charge on its surface. This can be a plastic 23 belt, for example, or a selenium drum of the type used in Xerox TM photocopiers. This 24 carrier surface 24 is passed tllrough a charging station . 5 where predetermined electrostatic charge 25A (an electrostatic ''image") is created on a predetermined area 26 of the transfer surface. This charged surface 25A then passes through a step 26 27 wherein powder 10 is deposited on the chalged carrier surface in a sufficient arnount 28 26A to neutralize the charge carried by the carrier surface. Thereafter. the carrier 29 surface, carrying the predetermilled amoullt 26A of powder on its surface. is passed to a powder discharging device 30 which discharges the powder 26A from the surface ~4 CA 022~9404 1999-01-04 W 098/00337 PCTrUS97/10494 onto a p~k~ging material 28? which may have indentations 29 for receiving the 2 powder. The packaging material 28 cont~ining its charge of powder 26A~ then passes 3 through a package sealing step 32.
4 As mentioned previously in discussing Fig. 1~ the carrier surface with the electrostatic charge carries a known amount of charge on its surface and the polarity 6 of this charge is opposite to that of the powder particles suspended in the chamber.
7 The charged particles migrate to the charged surface because of the attraction by the 8 opposite nature of the charges. This migration of the particles continues until the 9 charge on the carrier surface is neutralized.
The actual amount of powder mass transferred to the carrier surface is a 11 function of the mass to charge ratio of the charged particles. Although it is dif~lcult to 12 achieve a linear relationship between the mass and the actual charge~ it is possible to 13 establish a fixed relationship between the surface area of the powder particles and the 14 charge the powder particle is carrying at charge saturation. I~owever, the surface area of a mixed group of powder particles of difl'erent sizes and shapcs can be extremely 16 difficult to calculate m~them~tically~ particularly when the shapes are irregular~ (e.g.
17 non spherical, microcrystalline~ etc.) As mentioned earlier. the simplest method of 18 determining the amoullt and area of charge to attract a given weight of particles is to 19 estimate the correct area and charge and then apply the estimated charge to the estimated area on the carrier surface 24 and expose this selectively charged area to a 21 mass of powder which has been ionized in tlle ionizing step. The amount of powder 22 deposited can then be readily measured at the discharge step. Thereafter~ either the 23 size of the charged area or the arnount of cllarge applied to the area at the charging 24 station 25 can be adjusted upwardly or downwardly to provide the correct amount of charge, both in area and charge intensity~ for picking up a desired weight of oppositeiy 26 charged powder.
27 Referring now to Figs. 3, 4. and 5 olle preferred apparatus for accomplishing 28 the invention is illustrated schematically in Fig. 3~ with details of the components 29 thereof being shown in Figs. 4 and ~. The charge carrying surface is illustrated as a photo sensitive drum 24A which rotates between the charge "image" exposure 25 CA 022~9404 1999-01-04 O 98/00337 PCT~US97/10494 which creates a charge ~'image" 25A on the surface of the drum 24A. (see Fig. 4)2 This "image" exposure can be a light source e.ga laser beam (or other controllable 3 photon source). which is capable of creating an e}ectrostatic "image" 25A on the 4 surface of the drum of a desired size and charge density. The charge "irnage" 25A is S then rotated to the image development station containing a bulk drug reservoir 78 and 6 a high frequency vibrator 80 and an electrostatic defector 82 for producing an ioni~:ed 7 cloud of drug powder which is attracted to the charge "image" 25 to neutralize charge 8 in the "image"~ thus, forming a powder "image" 26A cont~inin~; a predetermined 9 arnount of powder. (see Figs. 4 and 5) This powder "image" 26A is rotated to a drug transfer station 30 where it is released into the pockets 29 in the packaging layer 28.
11 This transfer to the pockets 29 is accomplished. in one preferred embodiment, by the 12 use of high voltage plate 56 (see Fig. 5) which overcomes the attraction of the charged 13 "image" 25A on the sul-face of the drum~ thus releasing the powder "image" 26A into 14 the pocket 29. The pocket containin~ the predetermined quantity of drug is then passed through the sealing step 3~.
16 Fit!. 6 shows another embodiment of tlle.invention wherein the micronized 17 drug particles 10 are carl ied on the surface ~f discrete carriers 60 which can be small 18 plastic beads. for example. When these plastic beads are contacted with an image 19 25A, the micronized particles 10 are transferred to the charge "image" 25A on the surface of the drum 24A from the discrete carrier balls 60. To accomplish this~ the 21 positive charge on the ima~e ~5A should be lligher than the positive charge on the 22 surface of the individual carriers 60.
23 Figs. 7 and 8 show additional details of means for both handling drugs and 24 providing aerosolization and ionization to provide a suspended stream of ~me drug powders having a predetermined size and charge and for delivering same to a 26 meterin~ chamber 86. ~n Fig. 7 and 8. elements 16A. 18A and 20A and 16B. 18B and 27 20B correspond to the equivalent elements in Figs. 2~ 3 and 4.
28 Since repeatability is important for dru~ meterin~ it is necessary to effectively 29 address the issue of charge to mass variation with particle size.
CA 022~9404 1999-01-04 W 098/00337 PCT~US97/10494 One method of over-coming this problem is to control the particle size 2 distribution in the drug powder. Fig. 8 shows one implementation to achieve this 3 control of particle size. The voltage on the electrostatic deflector 82 is adiusted to 4 control the particle sizes to be suspended in the holding chamber for delivery to the ionization chamber. Once the desired particle sizes are suspended they are drawn into 6 the ionization charnber to ensure surface charge saturation on the,particles. This will 7 give a known charge to the mass ratio.
8 Fig. 7 shows an alternative means for controlling the size distribution. A high 9 velocity air stream 84 is used to deaggregate and aerosolize the powder. Thedeaggregated powder is then contained in holding chamber 18A. The purpose of the11 holding chamber is to allow the larger size particles to settle, thereby producing a 12 favorable particle size distribution. The particle size distribution is a function of the 13 holding time as shown in Fig. 9. The suspended particles are then ionized and 14 exposed to the charge image as shown in at 26 in Fig. 3 Fig. 9 shows the percentage of particles sizes suspendcd in a holding chamber 16 as a function of timc. Such a chamber may be provided with a slow upward flowing 17 air current to m~int~in the aerosol suspension. ~s can be seen. the percentage of 18 suspended particles is very largely determined by particle size (where S equals small 19 particle sizes, M equals medium particle sizes and L equals large particle sizes).
Through experiment one can select a time slot T that will give the desired particle size 21 distribution for any particle drug dosage. Additionally. or in place of settling time, 22 one or more filters can be used for obtaining a given particle size range.
23 Fig. 10 is similar to Figure 4 except that the Image Development Station 26 iri 24 this figure is replaced with the Sta~ionary electrode 26B and an air passageway 50 for carrying the aerosolized powder. The rotatin~g drum 24 has a dielectric or 26 photoreceptor surface on to which is deposited the latent image. As an example the 27 aerosolization chamber would be similar to that shown in Figure 7. The metering 28 chamber in Figure 7 is then the air-passageway 25 between the dielectric surface 24 29 and the stationary electrode 26B with a bias voltage V applied between surface 24 and electrode 26B. The undeposited powder then exits at the right sidc of this air-CA 022~9404 1999-01-04 W O 98/00337 PCTrUS97/10494 passageway to be collected for later use or recirculated back into the aerosolization 2 chamber.
3 Figure 11 above shows an ion projection print head where an ion beam is used 4 to produce a charge "image" on a dielectric surface. The corona wire 52 has a high S voltage applied to it which causes the air to breakdown and produces the ions 52A
6 necessary for the operation of the ion projection printers. The rem~in~ r of the ion 7 projection print head includes the usual control electrode 54~ screen electrode 56 and 8 insulator 58. The relative potential that is applied to the control and screen electrodes 9 then regulates the amount of ions 25C that will be metered and deposited on to the dielectric surface 24 these ions being deposited on the surface to form the latent image 11 25A. Both the intensity and size of the ion beam can be adjusted as will be apparent 12 to one of ordinary skill in the art. The advantage of this system is that it does not 13 require a photosensitive surface and can therefore be rugged making it suitable for the 14 manufacturing enviromnent.
The invention also may be advantageously employed for forming pills of 16 microgram quantities of a drug by printing on a substrate an "image" formed of 17 discrete dots of finely divided drug particles~ the quantity of particles in a dot 18 corresponding to a given quantity of drug, and packaging one or more of the dots as a 19 predetermined therapeutic drug dose.
Claims (11)
1. The method of packaging powder characterized by the steps of developing a predetermined electrostatic charge having a predetermined "image" area on a powder carrier surface, contacting said carrier surface with a sufficient amount of powder to neutralize said charge, moving said powder and said surface to a transfer station, transferring said powder to said package and sealing a package to contain a amount of transferred powder.
2. The method of claim 1, characterized in that said predetermined charge and area on said carrier surface are estimated, said estimated electrostatically charged area is then exposed to said powder of opposite charge and the amount of powder attracted to said predetermined area is measured, thereafter necessary adjustments to the amount of charge and/or the area is made to attract the predetermined desired amount of powder to said "image" area.
3. The method of claim 1, characterized in that the charge "image" is produced by an ion beam whose intensity and/or area can be varied, or by a photon beam whose intensity and/or area can be varied.
4. The method of claim 3. characterized by the step of controlling particle sizedistribution of particles in the powder deposited on the charge "image".
5. The method of claim 1, characterized in that pills of predetermined therapeutic drug dose are formed by printing on a substrate an "image" formed ofdiscrete dots of finely divided drug particles, the quantity of particles in a dot corresponding to a given quantity of drug, and packaging one or more of said dots as a predetermined therapeutic drug dose.
6. Apparatus for packaging for powder characterized by comprising:
a source of powder 16;
a powder carrier surface 24;
means 26 for applying a predetermined electrostatic charge to a predetermined area of said carrier surface, to create a charge "image" 25A on said surface.
means 26 for applying to said powder an electrostatic charge opposite to that of said electrostatic charge on said carrier surface;
means for exposing said charged area of said area on said carrier surface to charged powder to create a powder "image" 26A on said carrier surface;
means 30 for transferring said powder adhering to said carrier surface to a transfer system and neutralizing said electrostatic charge on said carrier surface to cause the powder to transfer into a package 28 therefor; and, means 32 for sealing said package.
a source of powder 16;
a powder carrier surface 24;
means 26 for applying a predetermined electrostatic charge to a predetermined area of said carrier surface, to create a charge "image" 25A on said surface.
means 26 for applying to said powder an electrostatic charge opposite to that of said electrostatic charge on said carrier surface;
means for exposing said charged area of said area on said carrier surface to charged powder to create a powder "image" 26A on said carrier surface;
means 30 for transferring said powder adhering to said carrier surface to a transfer system and neutralizing said electrostatic charge on said carrier surface to cause the powder to transfer into a package 28 therefor; and, means 32 for sealing said package.
7. The apparatus of claim 6, characterized in that the means for placing the electrostatic "image" on the carrier surface is adjustable both in intensity and area so that the exact amount of electrostatic charge and area thereof can be controlled.
8. The apparatus of claim 6, characterized by additionally including a means to control the powder particle size distribution to ensure repeatability and accuracy of powder metering.
9. The apparatus of claim 8, characterized by further comprising a high frequency vibrator 80 for deaggregating the powder, and an electrostatic potential means 82 for aerosolizing the particle size distribution of interest.
10. The apparatus of claim 6, characterized by a high velocity air stream 84 for deaggregating and aerosolizing the powder particles, and a holding chamber 18B
for controlling the particle size distribution in the air stream using particle settling times.
for controlling the particle size distribution in the air stream using particle settling times.
11. The apparatus of claim 6, characterized in that the charge "image" is produced by an ion beam whose intensity and/or area can be varied, or by a photon beam whose intensity and/or area can be varied;
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/677,340 | 1996-07-02 | ||
| US08/677,340 US5699649A (en) | 1996-07-02 | 1996-07-02 | Metering and packaging device for dry powders |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2259404A1 true CA2259404A1 (en) | 1998-01-08 |
Family
ID=24718295
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002259404A Abandoned CA2259404A1 (en) | 1996-07-02 | 1997-06-23 | Metering and packaging device for dry powders |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US5699649A (en) |
| EP (1) | EP1025002A4 (en) |
| KR (1) | KR20000023560A (en) |
| CN (1) | CN1099981C (en) |
| AU (1) | AU717829B2 (en) |
| BR (1) | BR9710700A (en) |
| CA (1) | CA2259404A1 (en) |
| NZ (1) | NZ333638A (en) |
| WO (1) | WO1998000337A1 (en) |
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-
1996
- 1996-07-02 US US08/677,340 patent/US5699649A/en not_active Expired - Lifetime
-
1997
- 1997-06-23 EP EP97930068A patent/EP1025002A4/en not_active Withdrawn
- 1997-06-23 AU AU33983/97A patent/AU717829B2/en not_active Ceased
- 1997-06-23 BR BR9710700-0A patent/BR9710700A/en not_active IP Right Cessation
- 1997-06-23 NZ NZ333638A patent/NZ333638A/en unknown
- 1997-06-23 CA CA002259404A patent/CA2259404A1/en not_active Abandoned
- 1997-06-23 WO PCT/US1997/010494 patent/WO1998000337A1/en not_active Application Discontinuation
- 1997-06-23 CN CN97197063A patent/CN1099981C/en not_active Expired - Fee Related
-
1999
- 1999-01-02 KR KR1019997000002A patent/KR20000023560A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| EP1025002A4 (en) | 2002-08-14 |
| AU3398397A (en) | 1998-01-21 |
| AU717829B2 (en) | 2000-04-06 |
| KR20000023560A (en) | 2000-04-25 |
| NZ333638A (en) | 2000-01-28 |
| US5699649A (en) | 1997-12-23 |
| EP1025002A1 (en) | 2000-08-09 |
| WO1998000337A1 (en) | 1998-01-08 |
| CN1227527A (en) | 1999-09-01 |
| BR9710700A (en) | 2000-01-11 |
| CN1099981C (en) | 2003-01-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |