Dry powder inhaler delivery system

The invention relates to a blister disk, and an inhaler comprising said blister disk.

Various drugs in a dry powder mixture form may be inhaled directly into the lungs, through the mouth or nose. Inhalation allows the drug to bypass the digestive system and may eliminate the need for other more interventional drug application techniques, e.g., hypodermic injections, etc. Direct inhalation, can in some cases, allow smaller doses of a drug to be used to achieve the same desired results as the same drug taken orally. In other cases, inhalation can help to avoid undesirable side effects.

To provide for direct inhalation of a powdered drug, various dry powder inhalers have been used. Representative literature in the general field can be found in WO 92/04069, US 4778054, US 4294361, US 3759371, US 5172812, GB 2229697 and US 4627432. These dry powder inhalers typically deliver dry powder from a bulk reservoir, capsule, or blister package, for inhalation by the patient. For sealing the powdered drug from the environment (to reduce caking, contamination, etc.), individual discrete sealed dose containers, such as blisters are preferred. However, while various blister dry powder storage and delivery devices have been used, various disadvantages remain. For example, the blister must be strong enough to provide a good seal against the environment, but also be able to reliably release the drug powder when used by the patient. In addition, to better provide accurate doses, virtually all of the drug powder must be released from the blister into the inhalation device, without, of course, allowing any of the blister or container material mix with or flow out with the drug powder. As inhaled drugs, such as asthma drugs, may be used very frequently, the drug storage and delivery materials and device should advantageously be compact, low cost and easy to manufacture and use.

Accordingly, it is an object of the invention to provide an improved blister disk for use with an inhaler.

The above object is achieved by the blister disk having the features of claim 1. In this respect, it is noted that a blister disk having the features of the preamble of claim 1, is known from US Patent 4 778 054.

The blister disk of the present invention preferrably comprises a plurality of blisters radially spaced apart from one another. The blister shells are advantageously sealed onto an underlying metal foil shear layer. In a preferred embodiment, the shear layer is bonded onto a carrier disk. Shear tabs are advantageously bonded onto the shear layer, underneath each blister shell, with a gap separating the tabs from the tabs from the carrier disk.

Other objects and features of the present invention will become apparent from the following detailed description taken together with the accompanying drawings. The drawings, however, are provided for illustration purposes only and are not intended as a limitation on the scope of the invention.

In the drawings, wherein similar reference characters denote similar elements throughout the several views: <ul id="ul0001" list-style="none" compact="compact"><li>Fig. 1 is a perspective view of a dry powder inhaler;</li><li>Fig. 1a is a perspective view of the advance knob of the inhaler of Fig. 1;</li><li>Fig. 1b is a plan view of the inhaler of Fig. 1;</li><li>Fig. 1c is a schematically illustrated partial section view of the inhaler of Fig. 1;</li><li>Fig. 2 is a perspective view of a drug carrier disk, having exterior tabs;</li><li>Fig. 3 is a perspective view of an alternative carrier disk, having interior disk tabs;</li><li>Fig. 4 is another disk carrier embodiment having tabs contained within the disk;</li><li>Fig. 5 is an enlarged partial section view taken along line 5-5 of Fig. 2;</li><li>Fig. 5A is a top view thereof;</li><li>Fig. 5B is an exploded section view taken along line 5B-5B of Fig. A;</li><li>Fig. 5C is a bottom view thereof;</li><li>Fig. 6 is a side elevation view thereof, just prior to opening the blister;</li><li>Fig. 7 is a side elevation view thereof, just after the blister has been sheared open;</li><li>Fig. 8 is a section view of the carrier disk of Fig. 2 installed within a first embodiment of a dry powder inhaler;</li><li>Fig. 9 is a section view of the disk carrier of Fig. 2 installed within a second embodiment dry powder inhaler;</li></ul>

Turning now in detail to the drawings, as shown in Fig. 1, a dry powder inhaler <b>20</b> has a mouthpiece <b>22</b> which is covered by a cap <b>24</b> when not in use. A knob <b>26</b> on top of the inhaler <b>20</b> may be used to advance individual drug doses for delivery through the mouthpiece <b>22</b>. Referring to Figs. 1, 1b, and 1c, a blister opening mechanism <b>38</b> includes a center button <b>28</b> positioned over a spring <b>44</b> on a rocker arm <b>40</b>. The rocker arm <b>40</b> has a lever end <b>42</b> for pushing up on an interior tab <b>32</b> on a carrier disk <b>34</b> to shear or tear open a blister <b>36.</b>

The carrier disk <b>34</b> and blister <b>36</b> are further illustrated in Figs. 2-5. Fig. 2 shows a carrier disk <b>46</b> having exterior tabs <b>48</b> extending from radially spaced apart blisters <b>36</b> supported on a carrier disk <b>60</b>. Fig. 3 better illustrates the carrier disk <b>34</b> shown in Fig. 1c, which has interior tabs <b>32</b>. Fig. 4 shows another alternative carrier disk embodiment having tabs contained within the profile of the disk <b>50</b>. Shear pin holes <b>52</b> extend through the disk <b>50</b>, and in use, pins in an inhaler device extend through the holes <b>52</b> to push against a tab contained within the disk <b>50</b>, to shear open the blisters <b>36.</b> The carrier disks <b>34, 46</b> and <b>50</b> may include an indexing/drive notch <b>72.</b>

Turning to Fig. 5 which illustrates an exterior tab carrier disk design, a blister shell <b>54</b> is positioned over a shear layer <b>56</b>. The perimeter of the blister shell <b>54</b> is advantageously heat sealed to the shear layer <b>56</b> as shown at <b>58</b> in Figs. 5 and 5a. Drug powder <b>62</b> is contained between the blister shell <b>54</b> and the shear layer <b>56</b>. A tab <b>48</b> underlies the shear layer <b>56</b>, below the blister shell <b>54</b>. The tab <b>48</b> is separated from the disk carrier <b>60</b> by a gap <b>64</b> all around, except for at the hinge line <b>68</b> (Fig. 7). The hinge line <b>68</b> may optionally be provided as an indented area. A stress concentrator <b>70</b>, can similarly be included as an option by providing a point or tooth on the disk carrier <b>60</b> at the innermost location of the gap <b>64</b>, just inside of where the blister shell and shear layer join. The stress concentrator can help start the shearing/tearing action of the shear layer.

The blister shell <b>54</b> and shear layer <b>56</b> are preferably metal, e.g., aluminum, foils. The disk carrier <b>60</b> and tab <b>48</b> are preferably injection molded or die cut plastic. The shear layer <b>56</b> is adhered to the disk carrier <b>60</b> and tab <b>48</b> with an adhesive <b>49</b>, and spans across the gap <b>64</b>, as shown in Figs. 5B and 5C.

Figs. 6 and 7 illustrate operation of the disk carrier <b>60</b> within an inhaler. As shown in Fig. 6, the disk <b>60</b> rests on a support <b>84</b> positioned just inside of the gap <b>64</b>. The blister <b>36</b> is positioned over a guide wall <b>86</b>. As shown in Figs. 6 and 7, an actuator <b>80</b> pushes up on the tab <b>48</b>, which, acting as a lever, causes the shear layer <b>56</b> (which forms the bottom surface of the blister <b>36</b>) to shear and tear away from the blister shell <b>54</b>, thereby opening the blister. The powder <b>62</b> contained within the blister <b>36</b> falls free of the blister <b>36</b> and disk <b>60</b>, into a chute in the inhaler. The tab <b>48</b> pivots about the hinge point <b>68</b>. As this occurs, the heat seal <b>58</b> remains intact, with the opening of the blister <b>36</b> provided by the tearing of the shear layer <b>56.</b>

Referring to Fig. 8, a dry powder inhaler <b>100</b> has a housing <b>102</b>, a mouthpiece <b>104</b> and an impeller <b>108</b> within a mixing chamber <b>106</b>. A motor <b>110</b> powered by batteries <b>112</b> spins the impeller <b>104</b>. As the blister <b>36</b> is sheared open, as shown in Figs. 6 and 7, the powder from the blister <b>36</b> falls into the mixing chamber <b>106</b>, is mixed with air, and can be drawn out and inhaled by the patient. Fig. 9 shows an alternative inhaler embodiment having a centrally located mouthpiece <b>104</b>.

Thus, while several embodiments have been shown and described, it should be appreciated that many more modifications may be made, without departing from the scope of the present invention.