Patent Document

RELATED APPLICATION 
     The present application is a continuation in part application of U.S. patent application Ser. No. 11/520,598 filed on Sep. 14, 2006, now U.S. Pat. No. 7,935,088, which is a continuation of U.S. patent application Ser. No. 10/790,866 filed on Mar. 3, 2004, now abandoned, which claims priority under 35 U.S.C. §119(b) to foreign application GB 0304822.0 filed on Mar. 15, 2004 which are entirely herein incorporated by reference and to which the reader is directed for further information. 
    
    
     BACKGROUND 
     1. Field of the Present Patent Application 
     The present patent application is generally directed to dose setting mechanisms for drug delivery devices. More particularly, the present patent application is generally directed to drug delivery devices, such as pen type drug delivery devices. Such devices provide for self administration of medicinal product from a multi-dose cartridge and permit a user to set the delivery dose. The present application may find application in both disposable and reusable type drug delivery devices. However, aspects of the invention may be equally applicable in other scenarios as well. 
     2. Background 
     Pen type drug delivery devices have application where regular injection by persons without formal medical training occurs. This is increasingly common among patients having diabetes where self-treatment enables such patients to conduct effective management of their disease. 
     Diabetes has been shown to cause certain problems. For example, people with diabetes can get high blood pressure, kidney disease, nerve damage, heart disease, and even in certain circumstances blindness. The damage caused by these problems may occur in patients whose blood sugar has been out of control for years. Keeping blood sugar under control, by way of effective insulin administration, is one method that can help prevent this damage from occurring. 
     In addition, people with diabetes can go into “diabetic coma” if their blood sugar is too high. They can also develop blood sugar that is too low (i.e, hypoglycemia) if they don&#39;t get enough food, or they exercise too much without adjusting insulin or food. Both diabetic coma and hypoglycemia can be very serious, and even fatal, if not treated quickly. Closely watching blood sugar, being aware of the early signs and symptoms of blood sugar that is too high or too low, and treating those conditions early can prevent these problems from becoming too serious. 
     Pen type drug delivery devices have been designed and developed to help patients suffering from diabetes so as to prevent such problems from occurring. The circumstances identified above highlight a number of design considerations and criteria for drug delivery devices, especially those that may be used to treat diabetes. As just one example, one requirement is that the drug delivery device must be robust in construction. The drug delivery device must also be easy to use both in terms of the drug delivery device manipulation and understanding of the device&#39;s operation. Diabetics have to inject themselves repeatedly with insulin solution and the volume of insulin to be injected may vary from patient to patient and even from injection to injection. For at least this reason, certain diabetics may require drug delivery devices that allow the patient to inject successive measured dosages of the same or perhaps different preset volumes of insulin solution accurately and with minimum dexterity challenges. This presents a further design challenge since, in the case of certain diabetics, users may have impaired vision and/or may be physically infirm with limited dexterity. 
     The problem of a patient&#39;s impaired vision and limited dexterity is further exacerbated by drug delivery devices that force a patient to use his or her less dominant hand. In other words, people suffering from diabetes who prefer to use their left hand (i.e., left handed patients) have an even greater desire or need for a drug delivery device that takes this user preference into consideration so that the patient is no longer forced to use his or her less dominant or weaker hand. 
     For example, certain studies suggest that approximately ten percent of the adult population is left-handed. It is also generally known that these left-handed individuals are sometimes placed at a disadvantage by the prevalence of right-handed tools and devices, such as medical drug delivery devices. Many tools and drug delivery devices are designed to be comfortably used with a user&#39;s right hand but not the user&#39;s left hand. As just one example, right-handed scissors, are arranged so that the line being cut along can be seen by a right-handed user, but is obscured to a left-handed user. Furthermore, the handles of these scissors are often molded in a way that is difficult or uncomfortable to be held by a left-handed user. Consequently, extensive use in such cases can lead to varying levels of efficiency and/or discomfort. As just another example of the right handed nature of tools and devices, the computer mouse is sometimes made to fit the right hand better than the left hand. 
     Consequently, with respect to the use of drug devices, many left handed patients, especially those already suffering from certain limitations such as partial blindness and limited dexterity, are further facing a heightened challenge when using a right-handed drug delivery device. These patients are being forced to use their less dominant hand to manipulate certain drug delivery devices, many of which have complicated dose setting and injection operations. This may be especially true where the left handed patient must user his or her less dominant right hand to manipulate the device to set an accurate dose of medicine (such as insulin) and then also inject a dose of medicine. As already mentioned above, inaccurate dose setting or injection of certain self administered drugs, such as insulin, could lead to fatal results. 
     There is, therefore, a general need to take these left handed and right handed issues into consideration in the design and development of drug delivery devices. Such drug delivery devices would allow a user to use his or her more dominant hand (their left hand) to set and then inject an accurate dose of medication. 
     SUMMARY 
     According to an exemplary embodiment, a drug delivery device comprises a drug delivery device housing and a medicament contained in said drug delivery device housing. A dose dial sleeve is positioned in said housing and rotatable to set a non-inverted dose of said medicament contained in said medical delivery device. Said non-inverted dose may be increased by turning said dose dial sleeve in a direction towards a user of said drug delivery device. With the drug delivery, said dose of said medicament may be decreased by rotating said dose dial sleeve in a direction away from said user. 
     In an alternative arrangement, a pen type drug delivery device comprises a drug delivery device housing. The housing having a distal end for mounting a needle assembly and a proximal end comprising a dose dial grip. A cartridge is contained in said housing, said cartridge containing a medication. A dose dial sleeve is rotatably mounted and operatively coupled to said dose dial grip. The dose dial grip may be rotated in a direction towards a user to set a dose. As said dose dial grip is rotated, both said dose dial grip and said dose dial sleeve translate away from said proximal end of said drug delivery housing. A non-inverted scale viewable in a window of said housing is representative of said dose. In this drug delivery device, said dose may be increased by turning said dose dial grip in a direction towards said user. 
     These as well as other advantages of various aspects of Applicants&#39; proposed drug delivery device will become apparent to those of ordinary skill in the art by reading the following detailed description, with appropriate reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments are described herein with reference to the drawings, in which: 
         FIG. 1  illustrates a sectional view of a first embodiment of the drug delivery device in accordance with the one arrangement of the device in a first, cartridge full, position; 
         FIG. 2  illustrates a sectional view of the drug delivery device of  FIG. 1  in a second, maximum first dose dialed, position; 
         FIG. 3  illustrates a sectional view of the drug delivery device of  FIG. 1  in a third, maximum first dose dispensed, position; 
         FIG. 4  illustrates a sectional view of the drug delivery device of  FIG. 1  in a fourth, final dose dialed, position; 
         FIG. 5  illustrates a sectional view of the drug delivery device of  FIG. 1  in a fifth, final dose dispensed, position; 
         FIG. 6  illustrates a cut-away view of a first detail of the drug delivery device of  FIG. 1 ; 
         FIG. 7  illustrates a partially cut-away view of a second detail of the drug delivery device of  FIG. 1 ; 
         FIG. 8  illustrates a partially cut-away view of a third detail of the drug delivery device of Figure; 
         FIG. 9  illustrates a first relative movement of parts of the drug delivery device shown in  FIG. 1  during dialing up of a dose; 
         FIG. 10  illustrates the relative movement of parts of the drug delivery device shown in  FIG. 9  during dialing down of a dose; 
         FIG. 11  illustrates the relative movement of parts of the drug delivery device shown in  FIG. 9  during dispensing of a dose; 
         FIG. 12  illustrates a partially cut-away view of the drug delivery device of  FIG. 1  in the second, maximum first dose dialed, position; 
         FIG. 13  illustrates a partially cut-away view of the drug delivery device of  FIG. 1  in the fourth, final dose dialed, position; 
         FIG. 14  illustrates a partially cut-away view of the drug delivery device of  FIG. 1  in one of the first, third or fifth positions; 
         FIG. 15  illustrates how a right handed user would set a dose with the drug delivery device of  FIG. 1 ; 
         FIG. 16  illustrates how a left handed user would set a dose with the drug delivery device of  FIG. 1 ; 
         FIG. 17  illustrates a scale arrangement that might be used for the drug delivery device of  FIG. 1 ; 
         FIG. 18  illustrates the scale arrangement of  FIG. 17  provided along an outer surface of a dose dial sleeve; 
         FIG. 19  illustrates how a right handed user would inject a dose with the drug delivery device illustrated in  FIG. 1 ; 
         FIG. 20  illustrates how a right handed user would set a dose with the drug delivery device of  FIG. 1 ; 
         FIG. 21  illustrates how a left handed user would set a dose with an alternative drug delivery device; 
         FIG. 22  illustrates an alternative scale arrangement that might be used for the alternative drug delivery device of  FIG. 20 ; and 
         FIG. 23  illustrates the alternative scale arrangement of  FIG. 22  provided along an outer surface of a dose dial sleeve. 
     
    
    
     DETAILED DESCRIPTION 
     Referring first to  FIGS. 1 to 5 , there is shown a drug delivery device  1  in accordance with the one arrangement in a plurality of operating positions: for dose setting and for dose administration or injection. The drug delivery device  1  comprises a housing having a first cartridge retaining part  2 , and second main (exterior) housing part  4 . A first end of the cartridge retaining means  2  and a second end of the main housing  4  are secured together by retaining features  6 . In this illustrated arrangement, the cartridge retaining means  2  is secured within the second end of the main housing  4 . 
     A cartridge  8  from which a number of doses of a medicinal product may be dispensed is provided in the cartridge retaining part  2 . Preferably, the cartridge contains a type of medicament that must be administered often, such as once or more times a day. One such medicament is insulin. A piston  10  is retained in a first end of the cartridge. A removable cap  12  is releasably retained over a second end of the cartridge retaining part  2 . 
     The dose setting mechanism of the drug delivery device illustrated in  FIGS. 1-5  may be utilized as either a disposable or reusable drug delivery device. Where the drug delivery device comprises a disposable drug delivery device, the cartridge cannot be removed from the device without destroying the device. Alternatively, where the drug delivery device comprises a reusable drug delivery device, the cartridge is removable and may be removed from the device without destroying the device. In the drug delivery device  1  illustrated in  FIGS. 1-5 , this drug delivery device is illustrated as a disposable drug delivery. However, those of ordinary skill in the art will recognize that the dose setting mechanism could also be used on reusable drug delivery devices as well. 
     In use, the removable cap  12  can be replaced by a user with a suitable needle unit (not shown). Such needle unit may be screwed onto a distal end of the housing or alternatively may be snapped onto this distal end. A replaceable cap  14  is used to cover the cartridge retaining part  2  extending from the main housing  4 . Preferably, the outer dimensions of the replaceable cap  14  are similar or identical to the outer dimensions of the main housing  4  so as to provide an impression of a unitary whole when the replaceable cap  14  is in position covering the cartridge retaining part  2 . In the illustrated arrangement, an insert  16  is provided at a first end of the main housing  4 . The insert  16  is secured against rotational or longitudinal motion. The insert  16  is provided with a threaded circular opening  18 . Alternatively, the insert may be formed integrally with the main housing having the form of a radially inwardly directed flange having an internal thread. 
     A first helical groove  19  extends from a first end of a piston rod  20 . In one arrangement, the piston rod  20  is of generally circular in cross section however other arrangements may also be used. The first end of the piston rod  20  (a distal end of the piston rod  20 ) extends through the threaded opening  18  in the insert  16 . A pressure foot  22  is located at the first end or distal end of the piston rod  20 . The pressure foot  22  is disposed to abut a second end of the cartridge piston  10 . A second helical groove  24  extends  15  from a second end of the piston rod  20  (a proximal end of the piston rod  20 ). In the illustrated arrangement, the second helical groove  24  extends from a second end or proximal end of the piston rod  20 . 
     In the illustrated arrangement, the second helical groove  24  comprises a series of part helical grooves rather than a complete helical groove. One advantage of this illustrated arrangement is that it is generally easier to manufacture and helps to reduce the overall force required for a user to actuate the device when dispensing the medicinal product from the drug delivery device  1 . 
     The first helical groove  19  and the second helical groove  24  are oppositely disposed, i.e., the grooves are of opposite hand. The second end of the piston rod  20  (i.e., the proximal end of the piston rod  20 ) is provided with a receiving recess  26 . A drive sleeve  30  extends about the piston rod  20 . The drive sleeve  30  is generally cylindrical. The drive sleeve  30  is provided at a first end with a first radially extending flange  32 . A second radially extending flange  34  is provided spaced a distance along the drive sleeve  30  from the first flange  32 . An intermediate helical groove  36  is provided on an outer part of the drive sleeve  30  extending between the first flange  32  and the second flange  34 . A helical groove  38  extends along the internal surface of the drive sleeve  38 . The second helical groove  24  of the piston rod  20  is adapted to work within the helical groove  38 . 
     A first end of the first flange  32  is adapted to conform to a second side of the insert  16 . A part nut  40  is located between the drive sleeve  30  and the main housing  2 , disposed between the first flange  32  and the second flange  34 . In the illustrated arrangement, the part nut  40  comprises a half-nut. The part nut  40  has an internal helical groove matching the intermediate helical groove  38  of the drive sleeve  30 . In one preferred arrangement, the outer surface of the part nut  40  and an internal surface of the main  5  housing  4  are keyed together by way of splines  42  (See, also  FIGS. 10 ,  11 ,  15  and  16 ) to prevent relative rotation between the part nut  40  and the main housing  4 , while allowing relative longitudinal in movement between these two components. 
     A shoulder  37  is formed between a second end of the drive sleeve  30  (a proximal end of the drive sleeve  30 ) and an extension  38  provided at the second end of the drive sleeve  30  (a distal end of the drive sleeve  30 ). The extension  38  has reduced inner and outer diameters in comparison to the remainder of the drive sleeve  30 . A second end of the extension  38  is provided with a radially outwardly directed flange  39 . As described in greater detail below, clicker  50  and a clutch  60  are disposed about the drive sleeve  30 , between the drive sleeve  30  and a dose dial sleeve  70 . 
     The clicker  50  is located adjacent the second flange  34  of the drive sleeve  30 . The clicker  50  is generally cylindrical and is provided at a first end with a flexible helically extending arm  52  (See, e.g.,  FIG. 6 ). A free end of the arm  52  is provided with a radially directed toothed member  54 . A second end of the clicker  50  is provided with a series of circumferentially directed saw teeth  56  ( FIG. 7 ). Each saw tooth comprises a longitudinally directed surface and an inclined surface. 
     In an alternative arrangement, the clicker further includes at least one spring member. The at least one spring member assists in the resetting of the clutch  60  following dispense of a previously set amount of medicament. The clutch  60  is located adjacent the second end of the drive sleeve  30 . The clutch  60  is generally cylindrical and is provided at a first end (a distal end) with a series of circumferentially directed saw teeth  66  (See, e.g.,  FIG. 7 ). Each saw tooth comprises a longitudinally directed surface and an inclined surface. Towards the second end  64  (a proximal end) of the clutch  60  there is located a radially inwardly directed flange  62 . The flange  62  of the clutch  60  is disposed between the shoulder  37  of the drive sleeve  30  and the radially outwardly directed flange  39  of the extension  38 . 
     The second end of the clutch  60  is provided with a plurality of dog teeth  65  (See, e.g.,  FIG. 8 ). The clutch  60  is keyed to the drive sleeve  30  by way of splines (not shown) to prevent relative rotation between the clutch  60  and the drive sleeve  30 . In one preferred arrangement, the clicker  50  and the clutch  60  each extend approximately half the length of the drive sleeve  30 . However, it will be understood by those of ordinary skill in the art that other arrangements regarding the relative lengths of these parts are possible. The clicker  50  and the clutch  60  are engaged as shown in  FIGS. 6 and 7 , for example. 
     A dose dial sleeve  70  is provided outside of the clicker  50  and clutch  60  and radially inward of the main housing  4 . The dose dial sleeve  70  comprises a distal end  73  and a proximal end  77 . A helical groove  74  is provided about an outer surface  72  of the dose dial sleeve  70 . The main housing  4  is provided with a window  44  through which a part of an outer surface  72  of the dose dial sleeve  70  may be viewed. 
     The main housing  4  is further provided with a helical rib  46 , adapted to be seated in the helical groove  74  on the outer surface of the dose dial sleeve  70 . In one preferred arrangement, the helical rib  46  extends for a single sweep of the inner surface of the main housing  4 . A first stop is provided between the splines  42  and the helical rib. A second stop, disposed at an angle of 180″ to the first stop, is formed by a frame surrounding the window  44  in the main housing  4 . 
     Returning to  FIGS. 1-5 , a dose dial grip  76  is disposed about an outer surface of the second end of the dose dial sleeve  70 . An outer diameter of the dose dial grip  76  preferably corresponds to the outer diameter of the main housing  4 . The dose dial grip  76  is secured to the dose dial sleeve  70  to prevent relative movement between these two components. The dose dial grip  76  is provided with a central opening  78 . An annular recess  80  located in the second end of the dose dial grip  76  extends around the opening  78 . A button of generally ‘T’ section is provided at a second end of the device. A stem  84  of the  85  button may extend through the opening  78  in the dose did grip  76 , through the inner diameter of the extension  38  of the drive sleeve  30  and into the receiving recess  26  at the proximal end of the piston rod  20 . The stem  84  is retained for limited axial movement in the drive sleeve  30  and against rotation with respect thereto. A head  85  of the button  82  is generally circular. A skirt  86  depends from a periphery of the head  85 . The skirt  86  is adapted to be seated in the annular  10  recess  80  of the dose dial grip  76 . 
     Operation of a right handed drug delivery device in accordance with a preferred arrangement will now be described. In  FIGS. 9 ,  10  and  11  arrows, A, B, C, D, E, F and G represent the respective movements of the button  82 , the dose dial grip  76 , the dose dial sleeve  70 , the drive sleeve  30 ,  15  the clutch  60 , the clicker  50  and the part nut  40  in one arrangement. 
     To dial a dose in the arrangement illustrated in  FIG. 9 , a user holds the main housing  4  in his or her left hand and uses the right hand to rotate the dose dial grip  76  (arrow B) in a direction away from the user. This is also shown in  FIG. 15  where the user uses his or her right hand to turn the dose dial grip  76  in the direction of arrow  120 : in a direction away from the user. With the clicker  50  and clutch  60  engaged, the drive sleeve  30 , the clicker  50 , the clutch  60  and the dose dial sleeve  70  rotate with the dose dial grip  76  towards the user. Audible and tactile feedback of the dose being dialed is provided by the clicker  50  and the clutch  60 . Torque is transmitted through the saw teeth  56 ,  66  between the clicker  50  and the clutch  60 . The flexible arm  52  deforms and drags the toothed member  54  over the splines  42  to produce a click. Preferably, the splines  42  are disposed such that each click corresponds to a conventional unit dose, or the like. 
     The helical groove  74  on the dose dial sleeve  70  and the helical groove  38  in the drive sleeve  30  have the same lead. This allows the dose dial sleeve  70  (arrow C) to extend in a proximal direction away from the main housing  4  (See, also  FIG. 15 ). In this manner, the drive sleeve  30  (arrow D) climbs the piston rod  20  at the same rate. At the limit of travel, a radial stop  104  (See, e.g.,  FIG. 12 ) on the dose dial sleeve  70  engages either the first stop  100  or the second stop  102  provided on the main housing  4  to prevent further movement. Rotation of the piston rod  20  is prevented due to the opposing directions of the overhauled and driven threads on the piston rod  20 . The part nut  40 , keyed to the main housing  4 , is advanced along the intermediate thread  36  by the rotation of the drive sleeve  30  (arrow D). 
     A visual indication of the dose that may be dialed, for example reference numerals or a scale, may be provided on the outer surface  72  of the dose dial sleeve  70 . (See, e.g.,  FIGS. 12 and 14 ) For example,  FIG. 17  illustrates a first scale arrangement  122  that could be provided on the dose dial sleeve outer surface  72 . In the scale arrangement  122  illustrated in  FIG. 17 , the arrangement  122  comprises five (5) columns of numerals: first column  124 , second column  126 , third column  128 , fourth column  130 , and fifth column  132 . In each column, the column of numerals decrease by a factor of two as one proceeds up the column. For example, in first column  124  located on the left hand side of arrangement  122 , first column  124  begins with the reference numeral “80” and decreases by a factor of two for each other numeral provided in this column (i.e, 80 Units then 78 Units then 76 Units, etc.). 
     This first scale arrangement  122  could provide a user certain visual indication through drug delivery device window  44  as the amount of dosage that a user sets. As may be seen from this first scale arrangement  122  provided in  FIG. 17 , a maximum scale reference numeral “80”  134  is provided at a bottom of the first column  124  and a minimum scale reference numeral “0”  136  is provided at the top of the fifth column  132 . With this scale arrangement  122 , the maximum settable dose by the drug delivery device  1  is “80” Units  134  and the minimum settable dose is “0” Units  136 . Between the maximum and minimum reference numerals  124 ,  136 , respectively, other doses are noted in increments of 2: (e.g., 2, 4, 6, 8 etc.). Single unit doses and odd unit doses may also be set and these are provided by way of plurality of scale marks provided between even numbered reference numerals. For example, half scale mark (“1” Units)  138  is provided between the minimum settable dose “0” Units  136  and 2 Units at the top of column  132 . 
     As may be also seen from this first scale arrangement  122 , the reference numerals increase going from a right hand side of the scale  122  or the fifth scale arrangement column  132  proceeding to the left side of scale  122  (towards the first scale arrangement column  124 ).  FIG. 18  illustrates the scale arrangement of  FIG. 17  provided along an outer surface  72  of the dose dial sleeve  70 . As can be seen from  FIG. 18 , scale arrangement  122  has the maximum settable dose value “80” provided at the distal end  73  and the minimum settable dose value “0” provided at the proximal end  74  of the dose dial sleeve  70 . Intermittent scale numerals “60” Units  172 , “40” Units  176  and “20” Units  178  are also provided. 
     Consequently, if scale arrangement  122  were provided on the dose dial sleeve  70  illustrated in  FIGS. 1-5 , as a user rotates the dose dial sleeve  70  by way of the dose dial grip  76  in a direction away from the user to set a dose with the user&#39;s right hand as illustrated in  FIGS. 9 and 15 , the dose dial sleeve  70  would extend out of the housing. For example, in  FIG. 15 , a user has set a dose of 30 Units with his or her right hand. 
     As shown in  FIG. 15 , as a user rotates the dose dial grip  76  and therefore the dose dial sleeve  70  in a direction away from the user (this direction illustrated by arrow  120 ), the scale arrangement  122  of  FIG. 17  provided along an outer drum of the dose dial sleeve  70  and are consequently readable in an upright orientation by way of window  44 . 
     Consequently, as the user uses his or right hand to rotate this dose dial sleeve, the user will receive correct visual confirmation of at least two important items: (1) the amount of the dose viewable by way of the window  44 , and (2) other indication (from label  112 ) that a drug delivery device provider may include on the housing. For example, label  112  could include: a description of the medicament provided in the drug delivery device, an expiration date of the medication, some type of color designation of the type of medicament provided, or some type of color designation of the type of drug delivery device provided. As just one example, the drug delivery device label  112  could provide a color indication of the type of insulin provided in the drug delivery device (e.g., long acting or short acting insulin) and/or could indicate that the drug delivery device is intended for right-handed or left-handed diabetics. That is, those diabetics who tend to favor their left hand to set a dose and/or inject a dose. 
     Returning to the drug delivery device  1  illustrated in  FIGS. 1-5 , when the final dose dispensed position (See, e.g.,  FIGS. 4 ,  5  and  13 ) is reached, a radial stop  106  formed on a second surface of the part nut  40  abuts a radial stop  108  on a first surface of the second flange  34  of the drive sleeve  30 , preventing both the nut  40  and the drive sleeve  30  from rotating further. In an alternative arrangement, a first surface of the part nut  40  may be provided with a radial stop for abutment with a radial stop provided on a second surface of the first flange  32 . This aids location of the nut  40  at the cartridge full position during assembly of the drug delivery device. 
     Should a user inadvertently dial beyond a desired dosage, the drug delivery device of  FIG. 9  allows the dosage to be dialed down without dispense of medicinal product from the cartridge (See, e.g.,  FIG. 10 ). For example, as illustrated in  FIG. 15 , a user has set a dose of 30 units. However, the user may now want to dial this dosage down without dispensing the previously set 30 Unit dose. In this arrangement, in order for the user to dial down the dosage, the dose dial sleeve  70  is rotated in a direction towards the user and the dose dial grip  76  is counter rotated (See, e.g., arrow B in  FIG. 10 ). This causes the system to act in reverse. The flexible arm  52  preventing the clicker  50  from rotating. The torque transmitted through the clutch  60  causes the saw teeth  56 ,  66  to ride over one another to create the clicks corresponding to dialed dose reduction. Preferably the saw teeth  56 ,  66  are so disposed that the circumferential extent of each saw tooth corresponds to a unit dose. 
     When the desired dose has been dialed, the user may then dispense this dose by depressing the button  82  (See, e.g.,  FIG. 11 ). As the user depresses the button  82  as illustrated in  FIG. 11  and  FIG. 18 , this displaces the clutch  60  axially with respect to the dose dial sleeve,  70  causing the dog teeth  65  to disengage. However the clutch  60  remains keyed in rotation to the drive sleeve  30 . The dose dial sleeve  70  and associated dose dial grip  76  are now free to rotate (guided by the helical rib  46  located in helical groove  74 ). 
     The axial movement deforms the flexible arm  52  of the clicker  50  to ensure the saw teeth  56 ,  66  cannot be overhauled during dispense. This prevents the drive sleeve  30  from rotating with respect to the main housing  4  though it is still free to move axially with respect thereto. This deformation is subsequently used to urge the clicker  50 , and the clutch  60 , back along the drive sleeve  30  to restore the connection between the clutch  60  and the dose dial sleeve  70  when pressure is removed from the button  82 . The longitudinal axial movement of the drive sleeve  38  causes the piston rod  20  to rotate  5  though the opening  18  in the insert  16 , thereby to advance the piston  18  in the cartridge  8 . 
     As can be seen from  FIG. 19 , as the user uses his or her right hand  200  to depress the button  82 , the user can monitor the dosage being dispensed by way of the scale arrangement  122  viewable via window  44 . In addition, as the user uses his or her right hand to depress the button  82  while administering the dose, other labeling  124  provided along the housing (See, e.g.,  FIG. 15 ) may also be visible. 
     It will be appreciated, however, that if a left handed user (i.e., a left handed diabetic) were to use his or her left hand to first set a dose and then second to administer this previously set dose, neither of these events would occur. For example,  FIG. 16  illustrates what would occur if a left handed user were to set a dose the drug delivery device illustrated in  FIGS. 1-5 . First, the left handed user would use his or her right hand to hold the drug delivery housing  4  and then turn the dose dial grip  76  with the user&#39;s left hand. In this orientation, the dose dial grip  76  must be rotated towards the user to set a dose rather than away from the user as with right handed drug delivery devices. In  FIG. 16 , this is represented by the arrow  110 . In such an event, both the scale arrangement  122  provided on the dose dial sleeve  70  and the labeling  112  would be inverted: they would be upside down rather than right side up as illustrated in  FIG. 16 . Therefore, for left handed users of the drug delivery device, both the scale provided on the dose dial sleeve as well as the labeling  112  must be modified so as to provide a readable scale and readable labeling for those left handed users. 
       FIG. 21  illustrates an alternative drug delivery device  140  wherein a dose may be selected by a left handed user by rotating the dose dial grip  144  in a direction of arrow  142 : that is, rotation of the dose dial grip  144  towards the user. In this arrangement, the user holds the housing  146  in their right hand. Then, the user can use his or her left hand to set a dose via dose dial grip  142 . As the user sets the dose, an alternative scale arrangement  152  must be provided so that the user can view the scale arrangement  152  by way of the drug delivery device window  150  in a right side up orientation, rather than the inverted scale  122  illustrated with the device  1  in  FIG. 16 . To provide a viewable scale that is readable and not inverted in this configuration, a modified scale from that provided in  FIG. 17  must be provided. 
       FIG. 22  illustrates one arrangement of an alternative scale arrangement  152  that could be provided along an outer surface of a dose dial sleeve in drug delivery device  140  of  FIG. 21 . The general construction of the alternative arrangement of the drug delivery device  140  along with its dose setting mechanism provided in  FIG. 21  is essentially identical to the general construction and operation of the drug delivery device  1  illustrated in  FIG. 1-5 . However, both the alternative scale arrangement  152  and alternative labeling  148  have been modified from the scale arrangement  122  and labeling  112  of device  1  illustrated in  FIG. 20 . In this alternative configuration, when a left handed user sets a dose, both the scale  152  and label  148  may be viewed in a correct orientation: where the scale and label are right side up and not inverted. 
       FIG. 22  illustrates one arrangement for such a modified scale  152 . As may be seen from this alternative scale arrangement, again five columns of reference numerals are provided: a first column  160 , a second column  162 , a third column  166 , a fourth column  166 , and a fifth column  168 . As can be seen from the first scale arrangement  122  illustrated in  17 , the orientation of the five columns of the alternative scale arrangement  152  has been alternated from the scale arrangement provided in  FIG. 17 . 
     Scale arrangement  152  comprises a maximum scale reference numeral “80”  154  and a minimum scale reference numeral “0”  156 . Similar to the scale arrangement provided in  FIG. 17 , the maximum scale reference numeral  154  is indicative of a maximum dose settable by the drug delivery device  140  and is “80” Units. Between the maximum and minimum reference numerals, other doses are noted in increments of 2: (e.g., 2, 4, 6, 8 etc.) Again, single unit doses and odd unit doses are also provided by way of the hash marks provided between even numbered reference numerals. For example, hash mark  170  indicates a 79 Unit dose, a dose between the maximum dose “80” Units and a dose of 78 Units. 
     Unlike the scale arrangement  122  of  FIG. 17 , however, in the alternative scale arrangement  152 , the reference numeral column containing the maximum settable dose “80” Units is provided along a right hand of the scale arrangement while the minimum dose “0” Units is now provided in the fifth scale arrangement column  168  provided at a left hand of the arrangement. Another difference between the modified scale arrangement  152  and the scale arrangement  122  provided in  FIG. 17  is that in the modified scale arrangement  152 , the dose setting numerals increase from a bottom of a column to a top of a column. For example, in the first column  160  of scale arrangement  152 , the dose will increase from the minimum “0,” 2, 4, and so on. Consequently, if modified scale arrangement  152  were to be provided on the dose dial sleeve of a drug delivery device  140  as illustrated in  FIG. 22 , the higher dose numerals  154  would reside along the distal end of the dose dial sleeve while the lower dose numerals would reside along a proximal end of the dose dial sleeve  70 . Consequently, as a user rotates the dose dial sleeve by way of the dose dial grip  76  in a direction towards the user with the user&#39;s left hand, the dose dial sleeve  70  would extend out of the housing and the scale arrangement  152  could be read from the right side up scale in viewable window  44  and would no longer be inverted as illustrated in  FIG. 16 . 
       FIG. 23  illustrates the scale arrangement of  FIG. 18  provided along an outer surface  72  of the dose dial sleeve  70 . As can be seen from  FIG. 18 , scale arrangement  122  has the maximum settable dose value “80” provided at the distal end  73  and the minimum settable dose value “0” provided at the proximal end  74  of the dose dial sleeve  70 . Intermittent scale numerals “60” Units  186 , “40” Units  184  and “20” Units  182  are also provided but their relative location along the outer surface  72  of the dose dial sleeve has been modified as compared to  FIG. 18 . 
     Another modification that can be made to the drug delivery device  140  of  FIG. 21  from the drug delivery device  1  illustrated in  FIG. 20  is that an orientation of label  148  has changed. Now, with the drug delivery device  140  of  FIG. 21 , as a user holds the device housing  4  in their right hand and sets a dose with their left hand by turning the dose dial grip in the direction of arrow  142 , the left handed user can now view the label in a right side up manner. That is, the label  148  is no longer inverted. 
     Exemplary embodiments of the present drug delivery device have been described. Those skilled in the art will understand, however, that changes and modifications may be made to these embodiments without departing from the true scope and spirit of the presently proposed drug delivery device, which is defined by the claims.

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