WO2005110519A1

WO2005110519A1 - Dry powder inhaler

Info

Publication number: WO2005110519A1
Application number: PCT/IN2004/000134
Authority: WO
Inventors: Satish Gokhale; Subhas Balaram Bhowmick; Kirti Wardhaman Ganorkar
Original assignee: Sun Pharmaceutical Industries Limited
Priority date: 2004-05-17
Filing date: 2004-05-17
Publication date: 2005-11-24

Abstract

The present invention provides a dry powder inhaler for administering medicaments in solid finely divided form to patients, wherein the dry powder inhaler is in the form of an improved diskhaler, wherein the improvement comprises replacement of two units, the first being a rotatable support and second being an annular blister pack with a single unit comprising a single disk (1) comprising a plurality of medicament containing cavities (6, 39) and wherein, the improvement further comprises of sealing layers that seal the cavities and are rupturable such that when ruptured, the medicament from the cavities is not retained in the cavity but is delivered to a chamber leading to a mouthpiece (21).

Description

DRY POWDER INHALER FIELD OF THE INVENTION

The present invention relates to a dry powder inhaler for delivery of medicaments in solid, finely divided form to a patient by oral inhalation. The present invention provides a compact, easy to carry and use, dry powder inhaler with means for dispensing a large number of doses of the medicament.

BACKGROUND OF THE INVENTION

Dry powder inhalers are known in the prior art. Many of the dry powder inhalers are known and marketed. Some of the marketed dry powder inhalers described in prior art include Spinhaler (United States Patent No 5,239,991), Rotahaler (United States Patent Nos. 4,210,140 and 4.206.758), Turbuhaler (United States Patent Nos. 4,524,769, 4,907,583, 4,668,218) and Diskhaler (United States Patent Nos. 4,81 1 ,731, 5,035,237) among the many others. Information about dry powder inhalers and formulations used therein is found in the art, for example textbooks like 'Particulate Interactions in Dry Powder Formulations for Inhalations" by Xian Zeng. Gary Martin and Christopher Marriott.

United States Patent Nos. 4,81 1,731 (assigned to Glaxo Group Limited) and 5,035,237 relate to a diskhaler kind of a dry powder inhaler for administering medicaments in solid finely divided form lo patients wherein the dry powder inhaler comprises a housing, a tray mounted in the housing which is movable between first and second positions relative to the housing, a rotatable support disk provided on the tray and adapted to receive a carrier provided with the medicament container. A plunger is operable to penetrate a container registered therewith to open the container to a pathway leading to an inhalation mouthpiece. This device uses a blister pack with 8 blisters in a single circular row of blisters. The blister pack uses technique of packaging a medicament by loading the medicament directly into a blister pack comprising a sheet, which may be laminated, of foil or plastics material and which is provided with a number of breakable or openable containers called "blisters" incorporating a sheet secured on a first sheet to form a cover or lid. But the blister packs have a limitation of the area of the blisters & thus of the medicament dose that can be filled in a blister, as they have a low depth to width ratio. Hence larger doses of medicament and larger number of doses cannot be readily administered using a blister pack. Also in case of diskhaler kind of dry powder inhalers, using a disk shaped blister pack mounted on a rotatable support, we have found that, providing more than 30 number of blister medicament units on the disk shaped blister pack makes the inhaler large and bulky.

PCT Application WO 02/053216 (assigned to Cipla Limited) relates to an improved dry powder inhaler comprising a cartridge with plurality of cavities containing the medicament, sealed on one surface with a pierceable sealing means and a piercing means which pierces the sealing means, so that the medicament is entrained and carried to the mouthpiece. In this device, the medicament remains in the cavity and is entrained in the inhaled air directly from the cavity and through a narrow air passageway in the piercing means itself. With this device, there is a possibility that not all medicament will be entrained in the inhaled air and carried to the mouthpiece, resulting in sub- optimal dose of the medicament available to the patient. Also the piercing means remains in the punctured cavity, when the patient inhales, which might increase the chances of entraining the pieces of the ruptured aluminum foil or sealing means, in the medicament being carried to the patient.

OBJECT OF THE INVENTION

It is the object of the invention to provide an improved compact, easy to carry and use, dry powder inhaler with means for dispensing a large number of doses of the medicament. It is a further object of the invention to reduce the number of components in the diskhaler. It is yet another object of the invention to provide a diskhaler with larger cavities for holding the medicament. Yet another additional object of the invention is to provide a diskhaler in which the medicament is efficiently delivered from the cavities into a chamber and then to the patient.

SUMMARY OF THE INVENTION

The present invention provides a dry powder inhaler for administering medicaments in solid finely divided form to patients, wherein the dry powder inhaler is in the form of an improved diskhaler, wherein the improvement comprises replacement of two units, the first being a rotatable support and second being an annular blister pack with a single unit comprising a single disk comprising a plurality of medicament containing cavities and wherein, the improvement further comprises of sealing layers that seal the cavities and are rupturable such that when ruptured, the medicament from the cavities is not retained ih the cavity but is delivered to a chamber leading to a mouthpiece. More specifically, the present invention provides a dry powder inhaler for administering medicaments in solid finely divided form to patients, comprising a) a bottom unit, b) a disk comprising a plurality of medicament containing cavities arranged in two concentric rings, which are sealed with rupturable sealing layers, c) a top cover comprising a movable slider puncture pin assembly, said movable slider puncture pin assembly comprising a puncture pin and means for, (i) positioning the assembly in a first position to register the puncture pin with medicament containing cavities in first concentric ring for rupturing successively the medicament containing cavities, (ii) preventing the assembly from moving from the first position until medicament containing cavities in first concentric ring are exhausted, (iii) thereafter, positioning the assembly in a second position to register the puncture pin with medicament containing cavities in second concentric ring and rupturing successively the medicament containing cavities, d) air inlet means through which air can enter the dry powder inhaler and air outlet means through which patient can inhale, whereby the medicament from a ruptured medicament containing cavity will be entrained in the air flow produced by the patient.

The present invention also provides a single disk comprising medicament containing cavities, instead of the conventionally used blister packs mounted on a support, which offers advantages such as minimizing operating parts of the device and its dimensions, allowing increase of the depth to width ratio of the blister medicament units resulting in use of larger doses of the medicament in the medicament containing cavities.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The dry powder inhaler of the present invention is illustrated by embodiments described here in below.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

Figures 1A, I B, IC, and I D, are various views of the disk comprising medicament containing cavities, holding 30 + 30 medicament doses;

Figures 2A, 2B show the assembly of the dry powder inhaler;

Figures 3 is the exploded view of the dry powder inhaler;

Figures 4A, 4B, 4C are the cut section views of the dry powder inhaler;

Figures 5A, 5B. 5C, 5D are variations of scored formation of turbulence elements in the passageway connecting the air inlet hole to the air outlet hole in the mouthpiece;

Figures 6A, 6B show the puncture pin slider position to puncture medicament containing cavities

0-30 in the first ring;

Figures 6C. 6D show the puncture pin slider position to puncture medicament containing cavities

31-60 in the second ring; Figures 7A. 7B' 7C, 7D. 7E show the puncture pin slider lock positions with respect to the disk comprising medicament containing cavities;

Figure 7A shows the disk comprising medicament containing cavities in the position wherein the medicament containing cavity number 1 is to be punctured;

Figure 7B shows the disk indexed to medicament containing cavity number 2; Figure 7C shows the disk when it has reached the 30^th medicament containing cavity in the first ring;

Figure 7D shows the position of the puncture pin slider with respect to the disk when the medicament containing cavity number 31 is ready to be punctured;

Figure 7E shows the disk indexed to medicament containing cavity number 32; Figures 8A, 8B, 8C are the top isometric, bottom isometric and side views of the puncture pin slider assembly, respectively;

Figures 9A, 9B show the slider positions in the top cover for the 0-30 position and 0-31 position, respectively

Figure 10A shows the exploded view of the disk comprising the medicament containing cavities and the bottom unit

Figures 10B and 10C are the horizontal section view and the vertical section view respectively showing the unidirectional ratchet assembly for the disk with respect to the bottom unit

Figure 11 shows the top views of a preferred embodiment of the inhaler of present invention

Figures 12 shows the internal view of the preferred embodiment of figure 11. The figures only represent embodiments of the present invention. The embodiments are meant only for the purpose of illustration of the present invention. Different parts of the dry powder inhaler of these embodiments are labeled in figures 1 to 12 and the labeling is described herein below.

Figure 1

1 : disk comprising a plurality of medicament containing cavities

2: numerical on disk

5: notch in disk for the slider lock pin 6: medicament containing cavities

Figure 2 1 : disk comprising a plurality of medicament containing cavities

8: mouthpiece cap

9: lop cover 10: bottom unit

12: anticlockwise direction of movement of the disk

13: air inlet hole

14: cut in top cover for cantilevered movement of the puncture pin

15: movable slider puncture pin assembly 16: counter window to show number of medicament containing cavity being ruptured

17: unidirectional movement of slider puncture pin assembly

18: position of slider puncture pin assembly to rupture medicament containing cavities in first ring of disk

19: position of slider puncture pin assembly to rupture medicament containing cavities in second ring of disk

Figure 3

1 : disk comprising a plurality of medicament containing cavities

2: numerical on disk

5: notch in disk for ihe slider lock pin 8: mouthpiece cap

9: top cover

10: bottom unit

1 : air inlet hole

15: movable slider puncture pin assembly 20: slot in top cover for movement of slider puncture pin assembly

21 : mouthpiece

22: medicament hole for medicament containing cavity in first ring of disk

23: medicament hole for medicament containing cavity in second ring of disk 24: ratchet on bottom unit for unidirectional rotation of disk

Figure 4

13: air inlet hole

15: movable slider puncture pin assembly

16: counter window to show number of medicament containing cavity being ruptured 22: medicament hole for medicament containing cavity in first ring of disk

23: medicament hole for medicament containing cavity in second ring of disk

27: passageway/chamber connecting the air inlet hole to air outlet hole in the mouthpiece

28: air flow to the mouthpiece through the passageway

29: medicament falling into the passageway/chamber 30: unidirectional movement of slider puncture pin assembly

3 1 : puncture pin

32: slider lock pin

Figure 6

14: cut in top cover for cantilevered movement of the puncture pin 15: movable slider puncture pin assembly

31 : puncture pin

32: slider lock pin

33: position of slider puncture pin assembly to rupture medicament containing cavities in first ring of disk 34: non-return position of slider puncture pin assembly to rupture medicament containing cavities in second ring of disk

35: position marking on slider

36: medicament falling into passageway from the first ring of disk

37: medicament falling into passageway from the second ring of disk Figure 7

1 : disk comprising a plurality of medicament containing cavities

5: notch in disk for the slider lock pin

15: movable slider puncture pin assembly

16: counter window to show number of medicament containing cavity being ruptured 32: slider lock pin

33: position of slider puncture pin assembly to rupture medicament containing cavities in first ring of disk

34: non-return position of slider puncture pin assembly to rupture medicament containing cavities in second ring of disk

38: direction of indexing of disk

Figure 8

31 : puncture pin

32: slider lock pin 35: position marking on slider

40: ratchet lever in slider puncture pin assembly for non-return movement

41: cover for slider puncture pin assembly movement slot in top cover

Figure 9

9: top cover 14: cut in top cover for cantilevered movement of the puncture pin

34: non-return position of slider puncture pin assembly to rupture medicament containing cavities in second ring of disk 42: non-return ratchet lock for slider puncture pin assembly in top cover

Figure 10

1 : disk comprising a plurality of medicament containing cavities

10: bottom unit

12: anticlockwise direction of movement of disk 13: air inlet hole

24: ratchet on bottom unit for unidirectional rotation of disk

43: ratchet lever in disk

44: cavity in the disk for flexing of the ratchet lever

Figure 12 45: stopper ring in the disk to prevent movement of slider puncture pin assembly from the first ring of medicament containing cavities to second ring of medicament containing cavities of the disk

46: removable cover over the passageway connecting the air inlet hole to air outlet hole in the mouthpiece 47: interlock on the bottom unit to prevent movement of the disk when the medicament containing cavity ready for rupturing, has not been ruptured

In an embodiment of the present invention, there is provided a dry powder inhaler, the compact view of which is illustrated in Figures 2A, 2B and 3. The dry powder inhaler for administering medicaments in solid finely divided form to patients comprises principal parts viz., a bottom unit ( 10) with a mouthpiece (21), a disk (01 ) designed to accommodate a plurality of medicament containing cavities (06). top cover (09) comprising a movable slider puncture pin assembly or slider ( 15) with a puncture pin or plunger (31) to rupture a medicament containing cavity registered therewith, referred to as slider puncture pin assembly or slider herein and illustrated in Figures 4A, 6B, 8 and 9. The slider puncture pin assembly is provided with means comprising a slider lock pin (32). a puncture pin (31 ) and an optional ratchet lever (40).

The disk (01) comprises a plurality of medicament containing cavities (06) arranged in two concentric rings, which are sealed with rupturable sealing layers. The medicament containing cavities (06) are sealed on both the faces/surfaces by a sealing layer, resulting in two concentric rings of a plurality of medicament containing cavities. The Figures 1A to IF show a disk used in a preferred embodiment of the invention, wherein the disk holds 30+30 medicament containing cavities in the first and second concentric rings where the medicament containing cavities in the first and second ring are in an in-line arrangement.

In an embodiment, the first ring and the second ring of medicament containing cavities on the disk, each contain 30 medicament containing cavities in-line with each other. Each medicament containing cavity on the disk is numbered (02) to indicate the number of the medicament containing cavity being ruptured. The medicament number on the disk or a suitable visible element of the disk may be colored red in the region from medicament containing cavities 50 to 60 in order to give an indication to the patient that only the last ten doses are remaining in the disk. There is provided a notch (05) in the disk into which the slider lock pin (32) fits to facilitate the smooth changing over of the puncture pin from the first concentric ring to the second concentric ring of the ring when medicament containing cavities in the first concentric ring are exhausted, as described herein below.

The movable slider puncture pin assembly is positioned in a first position (see Figures 6A, 6B, 7A and 9A) to register the puncture pin with medicament containing cavities in first concentric ring for rupturing successively the medicament containing cavities, prevented by the slider lock pin (32) abutting the disk, from moving from the first position (see Figure 7A) until medicament containing cavities in first concentric ring are exhausted, thereafter, positioned in a second position when the slider lock pin (32) moves inwards and upwards on an inclined plane on the top cover to be engaged with the notch (05) in the disk (see Figures 7C & 7D), to register the puncture pin with medicament containing cavities in second concentric ring and rupturing successively the medicament containing cavities (see Figures 6C, 6D, 7E and 9B). The slider lock pin assembly is prevented from moving from the second position by means of ratchet lever (40) until medicament containing cavities in second concentric ring are exhausted (see Figures 8A and 9B). It is to be noted that the ratchet lever means is optional and may not be necessary in all designs. In embodiments where the inhaler has a robust design, the ratchet lever is not essential. In such embodiments the slider puncture pin assembly registered with the medicament containing cavities in the second ring of the disk cannot be easily moved back to the first ring of the medicament containing cavities of the disk due to lesser degree of freedom of movement of the slider puncture pin assembly due to such a design of the slider puncture pin assembly as well as due to the operational friction forces.

In a preferred embodiment the first concentric ring is the outer ring and the second concentric ring is the inner ring of the disk. The terms outer and inner refer to direction when moving from the boundary to the center, of the disk.

Figure 7A illustrates the direction of indexing (38) for the disk having numbered medicament containing cavities (39). The bottom unit ( 10) comprises a mouthpiece (21) and a mouthpiece cap (08). The disk (01 ) is mounted on the tray of the bottom unit, which comprises an air inlet hole ( 13) and a ratchet (24) (see Figures 3, 10A and 10C) for the unidirectional rotation of the mounted disk. The bottom unit also contains the medicament hole (22 and 23) through which medicament from the ruptured medicament containing cavity in the first ring or second ring in the disk empties into the passageway or chamber connecting the air inlet hole to the air outlet hole in the mouthpiece. When not in use, the mouthpiece is covered by the mouthpiece cap.

As illustrated in Figures 4A to 4C, the air inlet hole is connected to a passageway (27) and the air flow (28) generated by the inhalation by the patient carries the medicament (29) via the air outlet means in the mouthpiece into the respiratory tract of the patient. In the illustrated embodiment, the angle of the air inlet hole passage may be from 45° to 135°. It is preferred that the angle is greater than 90°. Angle used in the more preferred embodiment is 06.5°. In the above embodiment of the present invention, the medicament containing cavities are located between the air inlet hole and the mouthpiece. In alternate embodiments, the air inlet hole(s) are located between the two rings of the medicament containing cavities or between the medicament containing cavity and the mouthpiece opening or outlet. The wall of the passageway leading into the air outlet hole can have various configurations of the scored formations of the turbulence elements. The scored formation acts to add turbulence to the medicament entrained in the air stream. The formation may be in the form of protrusions or projections of various shapes, for example, spiral, single or multiple ribs, linear, helical, circular, cone, wedge, rectangular and the like. The formation can also be in the form of depressions or dimples of various -shapes, for example, spiral, linear, helical, circular, cone, wedge, rectangular and the like. Figures 5A to 5D show different configurations of the scored formations of the turbulence elements on the wall of the passageway connecting the air inlet hole to the air outlet hole on the mouthpiece.

The disk (Of) is provided with a means for unidirectional movement, which comprises a ratchet lever (43) for associating with the ratchet (24) of the bottom unit as can be seen from Figures 10A to I OC. Cavity (44) in the disk allows ratchet lever (43) to flex outwards to enable unlocking from ratchet (24) upon rotation and then flex back into the next available ratchet (24) for locking into the next position. The proper registering of the ratchet lever of the disk with ratchet (24) of the bottom unit allows locking of the disk into its position and the shape of the ratchet and the ratchet lever allows only unidirectional movement of the disk in the anti clockwise direction. Hence the direction for movement of the disk is in anti clockwise direction (12), as can be seen from Figures 2A and 10A. When the patient moves the disk in the direction of the indexing, a click sound indicates that the next medicament containing cavity of the disk is in proper registration with the puncture pin. Alternatively a spring mechanism can be used for the rotational movement of the disk.

On the top of the disk (01) is the top cover (09). As can be seen from Figure 2A and 6A, there is provided a numerical indexing means in the form of a counter window (16) in the top cover to show the numerical on the disk in order to see the number of the medicament containing cavity being ruptured. There is also a cut ( 14) in the top cover for the cantilevered movement of the puncture pin. The counter window is attached to the slider puncture assembly as shown in Figures 8 and 9. The movement of the counter window along with the slider assembly can be seen in figure 7. In Figure 7A, the counter window shows the number one when the puncture pin assembly is registered with the first medicament containing cavity of the first ring of the disk. Figures 7B and 7C show the advancement of the number in the counter window with advancement of the disk (01 ). Figure 7D shows the counter window showing the number thirty- one corresponding to the first medicament containing cavity of the second ring of the disk. The counter window may show only the number of the medicament containing cavity which is registered with the slider and puncture pin assembly or it may show the numbers of the medicament containing cavities in both the first and second ring of the disk with which the slider and puncture pin assembly is registered with. The counter window and the numbering means are designed for the easy visibility to the patient of the number of the medicament containing cavity on the disk, being ruptured. The further advancement of the counter window number along with the puncture pin assembly can be seen in Figure 7E. There is also provided a slider (15) having a position marker (35) on it, in order to shift the position of the puncture pin from the first ring of the disk to the second ring. The slider can be moved in one direction (17) only and can be positioned such that the puncture pin is in a position (18) to puncture the medicament containing cavities of the first ring of the disk initially and later in a position (i9) to puncture the medicament containing cavities in second ring of the disk. There is a slot (20) in the top cover for the movement of the slider along with the puncture pin. As can be seen from figure 8A, the slider contains a slider lock pin (32), a ratchet lever (40) for non-return delivery and a puncture pin (31) set at an angle so as to rupture the medicament containing cavity at the center and a cover (41) for the slot. As illustrated in Figure 4A, the slider is moved in unidirectional way (30) after 1 to 30 numbered medicament containing cavities in the first ring of the disk have been consumed to take it into a position to puncture 31 to 60 numbered medicament containing cavities in the second ring of the disk.

Figures 6A and 6B illustrate the puncture pin slider assembly position (33) ready to rupture 1 to 30 numbered medicament containing cavities in the first ring of the disk, starting with medicament containing cavity number 1. After the rupture of the medicament containing cavity, the medicament falls (36) into the passageway or chamber from the first ring of the disk. Figures 6C and 6D illustrate the puncture pin slider assembly position (34) ready to puncture 3f to 60 numbered medicament containing cavities in the second ring of the disk, starting with medicament containing cavity number 3i. Once the movable slider pin assembly is moved to the second ring position, it is in a non-return position (34) due to the locking of the ratchet lever (40) provided on the movable slider puncture pin assembly with a ratchet lock (42) provided in the top cover of the dry powder inhaler as can be seen from Figure 9B. After rupture of the medicament containing cavity, the medicament falls (37) into the passageway or chamber from the second ring of the disk.

In operation, the patient loads the disk comprising the medicament containing cavities in the dry powder inhaler in case of a reusable device. The slider pin counter window (f6) will show the medicament containing cavity number 1 of the first ring to be in position with the puncture pin as illustrated in Figure 7A. He removes the mouth cap, holds the mouthpiece in his mouth, presses the cut in top cover ( 14) in order to depress the puncture pin and rupture the medicament containing cavity and inhales. The pressing of the top cover depresses the angled puncture pin in the medicament containing cavity so as to rupture the associated medicament containing cavity in the center of cavity by rupturing both the sealing layers. This makes available the full dose of the medicament in a reproducible manner in the passageway or chamber and passes into the mouthpiece of the dry powder inhaler. When the patient inhales, the air enters through the air inlet hole ( 13) and passes out through the mouthpiece having entrained medicament therein. In order to shift to the next medicament containing cavity, he moves the disk (Of) in an anti clock wise direction till a click sound is heard. This operation is continued till the 30^th medicament containing cavity is reached and ruptured. In this position the slider lock pin (32) moves inwards and upwards along an inclined plane on the top cover and gets engaged with the notch (5) in the disk. In order to go to the second ring of the medicament containing cavities, the patient has to slide the slider in the direction (30) permitted so that the slider lock pin moves inwards and upwards on an inclined plane along the notch. When this is done, the puncture pin is registered with the first medicament containing cavity of the second ring medicament containing cavities of the disk and the ratchet lever (40) in the movable slider puncture pin assembly becomes firmly locked against the ratchet lock (42) in the top cover of the inhaler to prevent any further movement. Also the slider is now non retractable due to the locking of the ratchet lever and ratchet lock, so as to prevent any non-return movement of the slider back to the first ring. In alternate embodiments, where the is no ratchet lever, the slider puncture pin assembly does not return to the first ring on its own account, due to the less freedom of movement of the slider assembly unit as well as due to the frictional forces. The puncture pin can now be moved along the second ring of medicament containing cavities from the doses 3f to 60.

Figures 1 1 and 12 illustrate a preferred embodiment of the dry powder inhaler of the present invention. In the inhaler of this embodiment, there is additionally present a stopper ring (45) on the disk (01 ). This stopper ring acts as a means to prevent the slider puncture pin assembly from moving from the first ring of medicament containing cavities to the second ring of the medicament containing cavities on the disk till all the medicament containing cavities on the first ring of the disk are consumed. In addition to the stopper ring (45) present on the disk as shown in figure f2A, there is also a provided a projection on the slider puncture pin assembly which projects on to the disk and just touches the stopper ring, when the slider puncture pin assembly is in the first ring of the disk (not shown). The slider puncture pin assembly can only be moved along the first ring to rupture the medicament containing cavities along the first ring of the disk, but cannot be moved to the second ring as the projection provided on the slider puncture pin assembly is obstructed by the stopper ring. The movable slider puncture pin assembly can only be moved from the first ring of the medicament containing cavities to the second ring of the medicament containing cavities, when all the medicament containing cavities in the first ring are consumed, and the projection provided on the slider puncture pin assembly encounters a break provided in the stopper ring which coincides with the notch provided in the disk, so as to allow the projection provided on the movable slider pin assembly to move inwards and upwards on an inclined plane on the top cover, beyond the stopper ring while simultaneously the slider lock pin of the slider pin assembly also moves inwards and upwards on the inclined plane on the top cover to engage with the notch, so that the puncture pin is now registered with the first medicament containing cavity of the second ring of the disk. Now, the projection of the slider puncture pin assembly, because of its peculiar seating along the inclined plane of the top cover, no longer obstructs the stopper ring and hence the disk can be freely moved ahead to rupture and consume the medicament containing cavities along the second ring of the disk. There is also a removable cover (46) over the passageway connecting the air inlet hole to air outlet hole in the mouthpiece as can be seen in figure 12b. This cover can be removed for cleaning of the passageway and mouthpiece. A means is also provided on the bottom unit to prevent movement of the disk when the medicament containing cavity ready for rupturing, has not been ruptured. The means provided is an interlock (47) which consists of three pins provided on the bottom unit as shown in figures 12A and 12B. Two of the pins are seen in figure 12A. One pin (not shown) engages with the holes in the disk from beneath. Another pin is activated by the serrations on the periphery of the disk. The third pin is activated by the top cover when the puncture pin assembly is pressed to rupture a medicament containing cavity. When the medicament containing cavity is not yet ruptured, a pin of the interlock engages with the disk from beneath and prevents it from moving ahead. When the medicament containing cavity is punctured, and the puncture pin assembly is pressed along with the top cover, the interlock is activated, by which the lower pin releases itself from the disk and now it can be moved ahead. While the disk is being moved, the serration on the outer periphery of the disk activates the lower pin, on account of which the disk is again locked and is unable to move ahead. In an alternate embodiment, a spring assembly is used in combination with the stopper ring and the projection provided on the slider puncture pin assembly which projects on to the disk.

In a preferred embodiment, the disk comprises 30 medicament containing cavities in the first ring and 30 medicament containing cavities in the second ring, in line with each. Different configurations of the two rings of the disk and different number of the medicament containing cavities on the disk are also possible and may be encompassed in the scope of the invention. The thirty medicament containing cavities in the first ring and thirty medicament containing cavities in the second ring may be staggered or out of line with each other. Some other configurations of the medicament containing cavities on the disk which may be typically be used in the present invention include 16 medicament containing cavities in each of the first and second concentric rings of the disk which arc either in line with each other or which are staggered or not in line with each other; or 32 medicament containing cavities in each of the first and second concentric rings of the disk which are either in line with each other or which are staggered or not in line with each other.

In one embodiment, the dry powder inhaler of the invention is disposable and has to be replaced with a new device when all the medicament containing cavities of the disk are exhausted. In another embodiment, the dry powder inhaler of the invention is reusable and the exhausted disk with the two rings of medicament containing cavities can be replaced with a fresh disk with two rings of medicament containing cavities. In this embodiment, there is no ratchet lever in the slider puncture pin assembly for the non-retractable locking of the slider puncture pin assembly when it enters the second ring of the medicament containing cavities of the disk. When all the medicament containing cavities in the second ring of the disk are consumed, the slider puncture pin assembly is pulled back to the outer first ring position in order to register with the first medicament containing cavity of the first ring of the fresh disk.

In one embodiment of the invention, the disk comprises one or more medicaments in the medicament containing cavities of the disk. For example, the first and second medicament are in different cavities and the first medicament and second medicament cavities are adjacent to each other or are located on the different rings of medicament containing cavities of the disk. In an embodiment of the invention, there is present an additional air inlet hole located on the slider puncture pin assembly, leading into the ruptured medicament containing cavity. This hole is located around the puncture pin and leads into the ruptured medicament containing cavity and into the medicament hole. In an alternate embodiment, the main air inlet hole (13) located on the top cover is absent and only the air inlet hole on the slider puncture pin assembly is present. The air inlet hole on the slider puncture pin assembly serves to directly entrain the medicament still remaining in the ruptured medicament containing cavity and making available more of the medicament to the patient. The dry powder inhaler of the invention may optionally have secondary air inlet holes located on the top or bottom or the sides of the mouthpiece in order to achieve an optimum balance of fine particle fraction of the medicament available to the patient and the resistance of the device, in order to be therapeutically effective as well as convenient for use to the patient.

The disk comprising medicament containing cavities, used in the dry powder inhaler of the invention may be made of any suitable material and may be prepared by a suitable process known in the art. The disk may be made from a polymer, metal, ceramic, composite and the like. It may be made by injection molding, die-casting, pressing, extrusion, casting, sintering, stamping, punching, coining and the like. Typically the disk may be made by injection molding from suitable polymers like polycarbonate. The sealing layers sealed on the disk may be any suitable rupturable or pierceable material. Typically aluminum foil or its combination with paper or polyester (PET) or polycarbonate and the like may be used as a sealing layer. The sealing layers may be sealed to the disk typically by ultrasonic sealing, heat sealing, impulse sealing, hermetic sealing and the like.

In all the above embodiments, any one or all the components of the dry powder inhaler can be made photo luminescent to enable the patient to access the inhaler even in darkness. The various components of the dry powder inhaler can be made transparent or translucent in order to make easy the visualization of the used or unused medicament containing cavities. Also a "soft feel" material can be incorporated in any of the components of the dry powder inhaler preferably the sides of the device where the patient grips the dry powder inhaler in order to administer a dose. The "'soft feel" material used may be a TPE (Thermoplastic elastomer) with a shore hardness of about 30 to about 50. Also as mentioned before, the medicament dose number on the disk of doses 50 to about 60 may be in red color to remind the patient of the near exhaustion of the doses in the disk. Several modifications of the invention can be envisaged without departing from the nature and the scope of the invention as described in the description herein above. For instance the dry powder inhaler can be made of inert metal or reinforced plastics and synthetic polymeric material. The mouthpiece of the dry powder inhaler may be made of any moldable or formed plastic and may be of a suitable size and shape.

^• Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. It should be emphasized that the above-described embodiments of the present invention, particularly any "preferred" embodiments, are merely possible examples of the invention of implementations, merely set forth for a clear understanding of the principles of the invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed lo limit the scope thereof.

Claims

CLAIMS:

1. A dry powder inhaler for administering medicaments in solid finely divided form to patients, wherein the dry powder inhaler is in the form of an improved diskhaler, wherein the improvement comprises replacement of two units, the first being a rotatable support and second being an annular blister pack with a single unit comprising a single disk comprising a plurality of medicament containing cavities and wherein, the improvement further comprises of sealing layers that seal the cavities and are rupturable such that when ruptured, the medicament from the cavities is not retained in the cavity but is delivered to a chamber leading to a mouthpiece.

2. A dry powder inhaler as in claim 1, wherein the disk comprises atleast thirty medicament containing cavities.

3: A dry powder inhaler as in claim I. wherein the disk comprises the plurality of medicament containing cavities arranged in two concentric rings.

4. A dry powder inhaler as in claim 1 , wherein the disk comprising the plurality of medicament containing cavities is sealed on both faces by rupturable sealing layers. 5. A dry powder inhaler for administering medicaments in solid finely divided form to patients, comprising a) a bottom unit, b) a disk comprising a plurality of medicament containing cavities arranged in two concentric rings, which are sealed with rupturable sealing layers, c) a top cover comprising a movable slider puncture pin assembly, said movable slider puncture pin assembly comprising a puncture pin and means for, (i) positioning the assembly in a first position to register the puncture pin with medicament containing cavities in first concentric ring for rupturing successively the medicament containing cavities, (ii) preventing the assembly from moving from the first position until medicament containing cavities in first concentric ring are exhausted, (iii) thereafter, positioning the assembly in a second position to register the puncture pin with medicament containing cavities in second concentric ring and rupturing successively the medicament containing cavities, d) air inlet means through which air can enter the dry powder inhaler and air outlet means through which patient can inhale, whereby the medicament from a ruptured medicament containing cavity will be entrained in the air flow produced by the patient.

6. A dry powder inhaler as in claim 5. wherein there is provided a means for preventing the movable slider puncture pin assembly from moving from the second position until medicament containing cavities in second concentric ring are exhausted.

7. A dry powder inhaler as in claim 6, wherein the means for preventing the assembly from moving from the second position until medicament containing cavities in second concentric ring are exhausted is a ratchet lever provided on the slider puncture pin assembly.

8. A dry powder inhaler as in claim 5, wherein there is provided a means for unidirectional movement of the disk comprising a ratchet lever in the disk and ratchet in the bottom unit.

9. A dry powder inhaler as in claim 5, wherein the said means on the movable slider puncture pin assembly are as follows

(a) for positioning the assembly in a first position to register the puncture pin with medicament containing cavities in first concentric ring for rupturing successively the medicament containing cavities; and preventing the assembly from moving from the first position until medicament containing cavities in first concentric ring are exhausted, there is provided a slider lock pin abutting the disk.

(b) for positioning the assembly in a second position to register the puncture pin with medicament containing cavities in second concentric ring and rupturing successively the medicament containing cavities, there is provided a notch on the disk and an inclined plane on the top cover, so that the slider lock pin can move inwards and upwards on an inclined plane, 10. A dry powder inhaler as in claim 5, wherein for positioning the movable slider puncture pin assembly in a first position to register the puncture pin with the medicament containing cavities in first concentric ring for rupturing successively the medicament containing cavities; preventing the assembly from moving from the first position until the medicament containing cavities in first concentric ring are exhausted, there is provided a projection on the slider puncture pin assembly which moves on an inclined plane along the top cover and a stopper ring on the disk.

I 1. A dry powder inhaler as in claim 5. wherein the inhaler is provided with a means to prevent movement of the disk when the medicament containing cavity ready for rupturing has not been ruptured.

12. A dry powder inhaler as in claim 1 1 , wherein the means to prevent movement of the disk when the medicament containing cavity ready for puncturing has not been punctured, comprises an interlock provided on the bottom unit of the dry powder inhaler.

13. A dry powder inhaler as in claim 5, wherein a numerical indexing means is provided by a counter window located on the top cover and numerical on the disk.

14. A dry powder inhaler as in claim 5, wherein the air inlet means is connected to the air outlet means by means of a passageway or a chamber.

15. A dry powder inhaler as in claim 14, wherein the passageway has scored formations of turbulence elements on its walls.

16. A dry powder inhaler as in claim 15, wherein the scored formations on the walls of the passageway has a spiral configuration.

17. A dry powder inhaler as in claim 5, wherein there is an air inlet hole located on the slider puncture pin assembly, leading into the ruptured medicament containing cavity.

18. A dry powder inhaler as in claim 5. wherein the plurality of medicament containing cavities comprise one or more medicaments.