Abstract:
The present invention relates to a reminder device for a drug delivery device, comprising: a base member, an adjusting element movably disposed with respect to the base member between at least two stop positions, and a display means comprising an information surface being only partially discernible through an aperture, wherein at least two designated segments of the information surface become selectively discernible by a displacement of the adjusting element relative to the base member.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a U.S. National Phase Application pursuant to 35 U.S.C. §371 of International Application No. PCT/EP2010/062433 filed Aug. 26, 2010, which claims priority to European Patent Application No. 09010974.5 filed on Aug. 27, 2009. The entire disclosure contents of these applications are herewith incorporated by reference into the present application. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a reminder or indicator device particularly adapted for drug delivery devices for keeping a user of the device informed about a given time schedule to apply or to take a particular medicament. 
       BACKGROUND 
       [0003]    With patients suffering chronic diseases, such like diabetes, frequent and regular administering of a particular medicament, like e.g. insulin has to be conducted. Since the patients are highly accustomed to a regular or irregular administering of the medicament, it may occur, that a patient already shortly after taking or injecting the medicament is no longer aware of this event. Hence, there is a certain danger, that the patient takes the medicament repeatedly. 
         [0004]    In practical use, also another scenario may take place, wherein a patient simply forgets to take the medicament at a particular time of the day, e.g. in the morning. 
         [0005]    Hence, with drug delivery devices particularly adapted and designed for self-medication, e.g. in a home environment, there always exists a non-negligible risk and danger of underdosage or overdosage, respectively. 
         [0006]    Document U.S. Pat. No. 5,482,163 for instance discloses an indicator apparatus including a cylindrical support having a longitudinal axis, an outer surface and a tapered flange structure. There, an expandable indicator ring is disposed over the outer surface being axially displaceable along the longitudinal axis to engage the tapered flange structure and which causes expansion of an indicator ring. The expandable indicator ring is rotatable about the longitudinal axis over the outer surface to each of a plurality of selected positions. 
         [0007]    However, such an indicator apparatus has not been considered to be applicable on pen-shape medical delivery devices for ergonomic as well as for technical reasons. 
       OBJECTS OF THE INVENTION 
       [0008]    It is therefore an object of the present invention to provide a reminder device particularly adapted for a drug delivery device which is rather simple, both in construction as well as in regard of its handling. 
         [0009]    The reminder device should be implemented in a space-saving and robust way. Moreover, the reminder device should be universally applicable and/or adaptable with various different types of drug delivery devices and medicaments to be administered therewith. 
       SUMMARY 
       [0010]    The present invention provides a reminder device for a drug delivery device, such like a pen-type injector. The reminder device can be universally adapted and modified according to the shape and geometry of the drug delivery device. For instance, the reminder device can be integrated in the drug delivery device or can otherwise be provided as a separate device being interconnectable with the drug delivery device. The reminder or indicator device comprises a base member and an adjusting element which is moveably disposed with respect to the base member between at least two stop positions. Preferably, the adjusting element is moveably disposed in or on the base member, thereby serving as a guiding structure or guiding element along which the adjusting element can be moved. Hence, the base member may serve as a support or as a support structure allowing the adjusting element to be variably disposed between the two stop positions. 
         [0011]    The reminder device further comprises a display means comprising an information surface. Display means and its information surface is arranged in such a way, that the information surface is only partially discernible through an aperture. Here, at least two designated segments or surface portions of the information surface become selectively discernible by a displacement of the adjusting element relative to the base member. For instance, when the adjusting element is in its first stop position, a first segment of the information surface is revealed while a second portion of the information surface remains concealed. With the adjusting element in its second stop position, the second surface portion of the information surface becomes discernible while the first surface portion is substantially concealed. 
         [0012]    Consequently, the size of the aperture through which the information content is to be displayed typically matches with the size of the surface portion comprising a particular information, being typically related to a time schedule. 
         [0013]    Therefore, the display means is particularly adapted to display time indicia or time information, like for instance morning, midday, evening, night. Further, depending on the type and characteristics of the medicament to be dispensed or to be injected by way of the drug delivery device, the display means preferably indicates a variety of time indicia that corresponds to the frequency, the particular medicament has to be administered. 
         [0014]    The information surface may comprise symbols, words, particular abbreviations or numbers. Furthermore and depending on the type of information disposed on the information surface, the aperture may be designed as a through opening in the base member, e.g. allowing to haptically detect the information disposed underneath on the information surface. This way, the information provided on the information surface can be read by simply touching the information surface, which is generally considered beneficial for patients suffering impaired vision. In the case of visible information, such like printed information it is also conceivable to implement the aperture by way of a transparent surface portion in the base member. 
         [0015]    According to a preferred embodiment, the base member is an integral housing component of the drug delivery device. Hence, the reminder device can be designed as an integral component of the drug delivery device. 
         [0016]    Furthermore it is intended, that the patient after each application or usage of the drug delivery device manually moves the adjusting element to one of said at least two stop positions. This way, the reminder device can be indicative on whether a particular dose of the medicament has already been taken. By integrating the reminder device into the drug delivery device it can almost be guaranteed, that the configuration of the reminder device exactly matches with the temporal schedule according to which the medicament is to be administered. 
         [0017]    According to another preferred aspect, the aperture is formed in the base member. With the adjusting element movably disposed inside the base member, at least one of the at least two designated segments of the information surface becomes discernible through the aperture. By having the aperture integrally formed in the base member or even in a housing component of the drug delivery device, construction and design of the reminder device can be kept on a rather simple and cost-efficient level. 
         [0018]    According to another preferred embodiment, the information surface is disposed on the adjusting element. Correspondingly, the base member and its aperture are substantially fixed and by moving the adjusting element relative to the base member, a designated segment of the information surface can be displaced to the region defined by the aperture, this way revealing or concealing respective portions of the information surface of the adjusting element. 
         [0019]    According to another preferred embodiment, the adjusting element is slidably disposed in or on the base member in an axial direction between at least a distal and a proximal stop position. In this context, the distal end of the drug delivery device faces towards the skin of the patient, whereas the proximal end of the drug delivery device faces away from an area of injection. The adjusting element can comprise a slider being slidably guided in or on the base member between at least its distal and its proximal stop position. Depending on whether the slider is in its proximal or distal stop position or in various designated positions therebetween, a respective and corresponding portion of the information surface is positioned in an overlapping manner with the aperture of the base member and can be thus displayed or sensed through touching. 
         [0020]    In a further preferred embodiment, the adjusting element comprises a sliding element or a slider having a gripping member protruding through the aperture. In a longitudinal cross-sectional view, the slider or sliding element may comprise a T-structure and related to a substantially cylindrically shaped base member, the slider may feature an information surface substantially extending in axial direction, whereas the gripping member substantially extends radially outwardly. Preferably, the gripping member extends substantially perpendicular from the centre of the information surface, such that a distal and/or proximal margin of the aperture of the base member may eventually serve as an effective stopper for the gripping member. 
         [0021]    Hence, since the gripping member radially outwardly or orthogonally protrudes from the display means and its information surface, axial displacement of the adjusting element in proximal and distal direction is limited by the gripping element hitting a respective proximal or distal margin of the aperture. 
         [0022]    It is further of advantage, when the adjusting element and the base member comprise mutually corresponding latching elements for keeping the adjusting element in a selected position. By way of the latching elements disposed on the adjusting element as well as on or in the base member, inadvertent displacement of the adjusting element can be effectively prevented. For instance, the adjusting element may feature protruding pins at distal and/or proximal end sections of its display means. These pins may for instance project radially outwardly, hence towards an inside wall section of the base member. Correspondingly, the base member may feature respective radially inwardly protruding latching elements adapted to form a positive interlock or a snap-in feature with said radially outwardly protruding pins of the display means and/or of its adjusting element. 
         [0023]    Axial position of mutually corresponding latching- or snap-in elements of the display means and the base member is chosen such, that the adjusting element is at least axially fixed in its at least two stop positions. Additionally, it is conceivable, that the display means comprises a toothed surface meshing with a flexible deformable ratchet member or the like. 
         [0024]    In a further preferred embodiment and irrespective of the implementation of the base member as integral or separate part of the housing of the drug delivery device, the base member is of substantially cylindrical geometry. In such configuration, the adjusting element may, according to another preferred aspect, be rotatably mounted on the outer circumference of the base member. Hence, instead of slidably displacing the adjusting element, it is also conceivable to rotatably displace said adjusting element for selectively displaying designated segments of the information surface disposed underneath the adjusting element. 
         [0025]    In this embodiment it is further of advantage, when the aperture is formed in the adjusting element while the information surface is disposed on the outer circumference of the base member. It may be also beneficial, when the information surface at least partially or entirely surrounds the circumference of the base member. Moreover, it is intended, that the adjusting element comprises a ring structure having an aperture and that by rotating the ring, a designated portion of the information surface becomes discernible through said aperture, either by way of visible perception or by way of tactile sensing. 
         [0026]    Hence, the information surface may comprise visible and/or haptic information discernible either by way of visual perception or by way of touching. 
         [0027]    In another independent aspect, the invention further relates to a drug delivery device for dispensing a dose of a medicament, preferably by way of injection. The drug delivery device comprises at least one housing component, e.g. a body component adapted to receive a drive mechanism and/or a cartridge holder component adapted to receive a cartridge filled with a medicament to be injected by the drug delivery device. Additionally, the drug delivery device comprises a cartridge filled with the medicament and having a piston slidably disposed therein. The piston typically acts as a proximal seal of the cartridge. By displacing the piston in distal direction, e.g. by way of a piston rod of a drive mechanism, a respective pressure builds up in the cartridge and if appropriately connected with a respective injection needle, a defined dose of the medicament can be expelled and thus dispensed. 
         [0028]    The drug delivery device therefore has a drive mechanism that comprises the piston rod to be operably engaged with the piston of the cartridge for dispensing of a dose of the medicament. 
         [0029]    The drug delivery device, which is typically designed as pen-type injector further comprises a reminder device as described above. 
         [0030]    According to a further preferred aspect, the housing component of the drug delivery device and the base member of the reminder device are integrally formed. In other words, the base member can be fully integrated in the housing component. Hence, the housing component may serve as the base member of the reminder device. This way, implementation of the reminder device does not require separate and additional components. Only a housing component of the drug delivery device has to be modified accordingly in order to receive e.g. a respective display means slidably or rotatably mounted to the base member. 
         [0031]    In a further, alternative embodiment, the base member and/or the reminder device is detachably connectable with the housing component of the drug delivery device. Here, the reminder device can be separately put on the market and already existing drug delivery devices can be retrofitted by a respective reminder device. 
         [0032]    The term “medicament”, as used herein, means a pharmaceutical formulation containing at least one pharmaceutically active compound, 
         [0033]    wherein in one embodiment the pharmaceutically active compound has a molecular weight up to 1500 Da and/or is a peptide, a proteine, a polysaccharide, a vaccine, a DNA, a RNA, a antibody, an enzyme, an antibody, a hormone or an oligonucleotide, or a mixture of the above-mentioned pharmaceutically active compound, 
         [0034]    wherein in a further embodiment the pharmaceutically active compound is useful for the treatment and/or prophylaxis of diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, thromboembolism disorders such as deep vein or pulmonary thromboembolism, acute coronary syndrome (ACS), angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis and/or rheumatoid arthritis, 
         [0035]    wherein in a further embodiment the pharmaceutically active compound comprises at least one peptide for the treatment and/or prophylaxis of diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, 
         [0036]    wherein in a further embodiment the pharmaceutically active compound comprises at least one human insulin or a human insulin analogue or derivative, glucagon-like peptide (GLP-1) or an analogue or derivative thereof, or exedin-3 or exedin-4 or an analogue or derivative of exedin-3 or exedin-4. 
         [0037]    Insulin analogues are for example Gly(A21), Arg(B31), Arg(B32) human insulin; Lys(B3), Glu(B29) human insulin; Lys(B28), Pro(B29) human insulin; Asp(B28) human insulin; human insulin, wherein proline in position B28 is replaced by Asp, Lys, Leu, Val or Ala and wherein in position B29 Lys may be replaced by Pro; Ala(B26) human insulin; Des(B28-B30) human insulin; Des(B27) human insulin and Des(B30) human insulin. 
         [0038]    Insulin derivates are for example B29-N-myristoyl-des(B30) human insulin; B29-N-palmitoyl-des(B30) human insulin; B29-N-myristoyl human insulin; B29-N-palmitoyl human insulin; B28-N-myristoyl LysB28ProB29 human insulin; B28-N-palmitoyl-LysB28ProB29 human insulin; B30-N-myristoyl-ThrB29LysB30 human insulin; B30-N-palmitoyl-ThrB29LysB30 human insulin; B29-N—(N-palmitoyl-Y-glutamyl)-des(B30) human insulin; B29-N—(N-lithocholyl-Y-glutamyl)-des(B30) human insulin; B29-N-(ω-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(ω-carboxyhepta-decanoyl) human insulin. 
         [0039]    Exendin-4 for example means Exendin-4(1-39), a peptide of the sequence H His-Gly-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Leu-Ser-Lys-Gln-Met-Glu-Glu-Glu-Ala-Val-Arg-Leu-Phe-Ile-Glu-Trp-Leu-Lys-Asn-Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-NH2. 
         [0040]    Exendin-4 derivatives are for example selected from the following list of compounds: 
       H-(Lys)4-des Pro36, des Pro37 Exendin-4(1-39)-NH2, 
     H-(Lys) 5 -des Pro36, des Pro37 Exendin-4(1-39)-NH 2 , 
     des Pro36 [Asp28] Exendin-4(1-39), 
     des Pro36 [IsoAsp28] Exendin-4(1-39), 
     des Pro36 [Met(O)14, Asp28] Exendin-4(1-39), 
     des Pro36 [Met(O)14, IsoAsp28] Exendin-4(1-39), 
     des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39), 
     des Pro36 [Trp(O2)25, IsoAsp28] Exendin-4(1-39), 
     des Pro36 [Met(O)14 Trp(O2)25, Asp28] Exendin-4(1-39), 
     des Pro36 [Met(O)14 Trp(O2)25, IsoAsp28] Exendin-4(1-39); or 
     des Pro36 [Asp28] Exendin-4(1-39), 
     des Pro36 [IsoAsp28] Exendin-4(1-39), 
     des Pro36 [Met(O)14, Asp28] Exendin-4(1-39), 
     des Pro36 [Met(O)14, IsoAsp28] Exendin-4(1-39), 
     des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39), 
     des Pro36 [Trp(O2)25, IsoAsp28] Exendin-4(1-39), 
     des Pro36 [Met(O)14 Trp(O2)25, Asp28] Exendin-4(1-39), 
     des Pro36 [Met(O)14 Trp(O2)25, IsoAsp28] Exendin-4(1-39), 
       [0041]    wherein the group -Lys6-NH2 may be bound to the C-terminus of the Exendin-4 derivative;
 
or an Exendin-4 derivative of the sequence
 
       H-(Lys)6-des Pro36 [Asp28] Exendin-4(1-39)-Lys6-NH2, 
     des Asp28 Pro36, Pro37, Pro38Exendin-4(1-39)-NH2, 
     H-(Lys)6-des Pro36, Pro38 [Asp28] Exendin-4(1-39)-NH2, 
     H-Asn-(Glu)5des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-NH2, 
     des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-(Lys)6-NH2, 
     H-(Lys)6-des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-(Lys)6-NH2, 
     H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-(Lys)6-NH2, 
     H-(Lys)6-des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39)-Lys6-NH2, 
     H-des Asp28 Pro36, Pro37, Pro38 [Trp(O2)25] Exendin-4(1-39)-NH2, 
     H-(Lys)6-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28] Exendin-4(1-39)-NH2, 
     H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28] Exendin-4(1-39)-NH2, 
     des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28] Exendin-4(1-39)-(Lys)6-NH2, 
     H-(Lys)6-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28] Exendin-4(1-39)-(Lys)6-NH2, 
     H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28] Exendin-4(1-39)-(Lys)6-NH2, 
     H-(Lys)6-des Pro36 [Met(O)14, Asp28] Exendin-4(1-39)-Lys6-NH2, 
     des Met(O)14 Asp28 Pro36, Pro37, Pro38 Exendin-4(1-39)-NH2, 
       [0042]    H-(Lys)6-desPro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-NH2, 
       H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-NH2, 
     des Pro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-(Lys)6-NH2, 
     H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-(Lys)6-NH2, 
     H-Asn-(Glu)5 des Pro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-(Lys)6-NH2, 
     H-Lys6-des Pro36 [Met(O)14, Trp(O2)25, Asp28] Exendin-4(1-39)-Lys6-NH2, 
     H-des Asp28 Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25] Exendin-4(1-39)-NH2, 
     H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-NH2, 
     H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28] Exendin-4(1-39)-NH2, 
     des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28] Exendin-4(1-39)-(Lys)6-NH2, 
     H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28] Exendin-4(S1-39)-(Lys)6-NH2, 
     H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28] Exendin-4(1-39)-(Lys)6-NH2; 
       [0043]    or a pharmaceutically acceptable salt or solvate of any one of the afore-mentioned Exedin-4 derivative. 
         [0044]    Hormones are for example hypophysis hormones or hypothalamus hormones or regulatory active peptides and their antagonists as listed in Rote Liste, ed. 2008, Chapter 50, such as Gonadotropine (Follitropin, Lutropin, Choriongonadotropin, Menotropin), Somatropine (Somatropin), Desmopressin, Terlipressin, Gonadorelin, Triptorelin, Leuprorelin, Buserelin, Nafarelin, Goserelin. 
         [0045]    A polysaccharide is for example a glucosaminoglycane, a hyaluronic acid, a heparin, a low molecular weight heparin or an ultra low molecular weight heparin or a derivative thereof, or a sulphated, e.g. a poly-sulphated form of the above-mentioned polysaccharides, and/or a pharmaceutically acceptable salt thereof. An example of a pharmaceutically acceptable salt of a poly-sulphated low molecular weight heparin is enoxaparin sodium. 
         [0046]    Pharmaceutically acceptable salts are for example acid addition salts and basic salts. Acid addition salts are e.g. HCl or HBr salts. Basic salts are e.g. salts having a cation selected from alkali or alkaline, e.g. Na+, or K+, or Ca2+, or an ammonium ion N+(R1)(R2)(R3)(R4), wherein R1 to R4 independently of each other mean: hydrogen, an optionally substituted C1-C6-alkyl group, an optionally substituted C2-C6-alkenyl group, an optionally substituted C6-C10-aryl group, or an optionally substituted C6-C10-heteroaryl group. Further examples of pharmaceutically acceptable salts are described in “Remington&#39;s Pharmaceutical Sciences” 17. ed. Alfonso R. Gennaro (Ed.), Mark Publishing Company, Easton, Pa., U.S.A., 1985 and in Encyclopedia of Pharmaceutical Technology. 
         [0047]    Pharmaceutically acceptable solvates are for example hydrates. 
         [0048]    It will be further apparent to those skilled in the pertinent art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Further, it is to be noted, that any reference signs used in the appended claims are not to be construed as limiting the scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0049]    In the following, preferred embodiments of the invention are described in greater detail by making reference to the drawings in which: 
           [0050]      FIG. 1  illustrates a first embodiment of an integrated reminder device in cross-sectional illustration, 
           [0051]      FIG. 2  shows the reminder device according to  FIG. 1  in a top view illustration and 
           [0052]      FIG. 3  is illustrative of another embodiment of the reminder device with a rotatable ring. 
       
    
    
     DETAILED DESCRIPTION 
       [0053]    The reminder device as illustrated in  FIGS. 1 and 2  is entirely integrated into a housing component  12 ,  14  of a drug delivery device  10 . As particularly illustrated in  FIG. 2 , the reminder device comprises a display means  18  positioned in a body  12  or main housing component of the drug delivery device. The drug delivery device further comprises a cartridge holder  14  at its distal end section and further has a dose button  16  at its proximal end for selecting and/or setting of a dose and eventually for initiating a dose dispensing procedure. 
         [0054]    The housing component  12  of the drug delivery device  10  of pen-injector type comprises a rectangular aperture  30  in form of a through opening. Underneath the aperture  30 , an adjusting element  22  comprising a sliding element is slidably disposed in axial direction. As illustrated in  FIG. 1 , the adjusting element  22  comprises a distal surface segment  25  and a proximal surface segment  27 . In the centre of the display means  18  or of the adjusting element  22  a radially upwardly, hence radially outwardly protruding gripping member  24  is provided allowing to manually displace the adjusting element  22  in either direction, hence distally, that is to the left in  FIG. 1  or proximally, that is to the right in  FIG. 2 . 
         [0055]    The adjusting element  22  can be displaced irrespective on the configuration of the drive mechanism of the drug delivery device  10  and/or independent of the filling level of the cartridge, being not further illustrated here. At its upper surface  26  facing towards the aperture  30  in the housing component  14 , the adjusting element is provided with visible or haptic information for indicating when the drug delivery device has been used for the last time or when a next usage of the drug delivery is due. Accordingly, since the adjusting element  22  and its information surface  26  comprise two surface segments  25 ,  27 , the illustrated display means  18  is adapted to indicate for instance a particular time or daytime, like morning or evening. 
         [0056]    Prior to or after usage of the drug delivery device  10  the sliding element  22  can be translationally displaced in distal direction, such that the surface segment  27  becomes visible through the aperture  30  of the housing component  12 . 
         [0057]    Longitudinal displacement of the sliding element  22  can be conducted by the gripping member  24  radially protruding through the aperture  30 . Preferably, the free end of the gripping member  24  at least slightly protrudes from the outer surface of the housing component  12 , thus facilitating its gripping and a respective axial displacement thereof. 
         [0058]    As can be further seen from  FIG. 1 , adjusting element  22  and the base member  12  comprise mutually corresponding latching elements  32 ,  33 ,  34 ,  35 . By way of said latching elements  32 ,  33 ,  34 ,  35 , the sliding member  22  can be kept and secured in its proximal or distal stop position, respectively. The latching elements  34 ,  35  of the base member  12  are for instance designed as radially inwardly protruding lugs being at least slightly deformable, thus allowing to displace a corresponding pin  32  of the adjusting element  22  into a position as depicted in  FIG. 1 . Here, the radially outwardly protruding pin  32  of the adjusting or sliding element  22  is positioned proximal compared to the corresponding radially inwardly protruding lug  34 . 
         [0059]    This way, a form fitting or positive interlock of adjusting element  22  and base member  12  can be attained. Similarly, when moving the adjusting element  22  in distal direction, hence to the left in  FIG. 1 , latching elements  32 ,  34  may disengage and upon reaching a distal stop position, oppositely located and mutually corresponding latching elements  33 ,  35  may engage. By providing a latching or fastening mechanism for the adjusting element  22  by elastically deforming at least one of the interengaging latching elements, a haptic feedback can be provided to the user, that a definite end position of the adjusting element  22  has been reached. 
         [0060]    The various protruding or latching elements  32 ,  33 ,  34 ,  35  together with corresponding recesses can be integrally formed with the housing components  12 ,  14  and/or with the adjusting element  22 . In particular, when the housing components  12 ,  14  and/or the adjusting element  22  are designed as injection moulded plastic components, formation of such protruding latching elements  32 ,  33 ,  34 ,  35  or corresponding recesses can be generated almost cost-neutral. 
         [0061]    Additionally, also the radially protruding gripping member  24  may but against a proximal or distal margin of the rectangular aperture  30  thus preventing any further axial displacement in the respective direction. 
         [0062]    In a further embodiment according to  FIG. 3 , the adjusting element  36  comprises a ring rotatably mounted on the outer circumference of a substantially cylindrical base member. In this embodiment, the adjusting element  36  comprises an aperture  38  for discerning or revealing a particular segment of an information surface  40  disposed underneath. With this display means  28  it is intended to rotate the ring-like adjusting element  36  in order to reveal particular time-related information, like certain numbers, abbreviation or even written words. 
         [0063]    Depending on the frequency of prescribed administering of a dose of the medicament, a plurality of surface segments can be arranged along the circumference of the base member  12 . For instance, numbers revealed by the aperture  38  may indicate the time of the day, when a prescribed medication has to be taken. Also, if a medicament has to be taken only once a day, respective abbreviations of the day names will be illustrated in the aperture, indicating on whether the medicament has been taken that particular day. 
         [0064]    As indicated in  FIG. 3 , the adjusting ring-like element  36  is directly mounted on a housing component  12  of the drug delivery device  20 . However, in particular with retrofitting embodiments it is also conceivable, that the base member is designed as a separate part that can be mounted on the outer circumference of the pen housing  12 . This way, also such housing components  12  of drug delivery devices  20  being of non-circular cross-section can be provided with a respective reminder device, wherein the base member provides a respective compensation means for mounting a rotatable ring  36  onto a non-circular-shape pen housing  12 .