Apparatus with a main control unit, a control unit and an electromechanical device and a method for operating such an apparatus
09813003 · 2017-11-07
Assignee
Inventors
- Shane Alistair Day (Warwickshire, GB)
- Barry Yates (Warwickshire, DE)
- Aidan Michael O'Hare (Coventry, GB)
Cpc classification
A61M5/14212
HUMAN NECESSITIES
A61M5/2448
HUMAN NECESSITIES
A61M5/19
HUMAN NECESSITIES
A61M5/30
HUMAN NECESSITIES
International classification
A61M5/30
HUMAN NECESSITIES
A61M5/19
HUMAN NECESSITIES
A61M5/145
HUMAN NECESSITIES
A61M5/24
HUMAN NECESSITIES
Abstract
The invention relates to an apparatus comprising an electromechanical device, a control unit, a main control unit and a motion detector, wherein said control unit is configured to control said electromechanical device. The invention also relates to a method for operating an apparatus with a main control unit, a control unit and an electromechanical device. The technical problem of providing an apparatus with an electromechanical device, the reliability of which is improved, is solved by an apparatus wherein the main control unit is configured to provide information to the control unit. The motion detector and the main control unit are configured such that information about the movement of the electromechanical device is provided by the motion detector at least to the main control unit. The technical problem is also solved by a method for operating an apparatus, in particular an apparatus or medical device according to the invention.
Claims
1. Apparatus comprising: an electromechanical device, a control unit, a main control unit and a motion detector, wherein said control unit is configured to control said electromechanical device, and wherein said electromechanical device is a motor, characterized in that said control unit and said main control unit are realized with microprocessors, said main control unit is configured to provide information to said control unit, and said motion detector and said main control unit are configured such that information about the movement of said electromechanical device is provided by said motion detector at least to said main control unit, wherein said main control unit is configured to provide information regarding control of the electromechanical device to said control unit, and said control unit is configured to provide a corresponding control signal to said electromechanical device to control said electromechanical device, wherein said motion detector and said main control unit are configured such that the information about the movement of said electromechanical device is provided by said motion detector to said main control unit and said control unit.
2. Apparatus according to claim 1, wherein said motion detector is configured to provide the information to said control unit.
3. Apparatus according to claim 1, wherein the main control unit is configured to control a switch to disconnect the control unit from the electromechanical device.
4. Apparatus according to claim 1, wherein the main control unit is configured to control a switch to disconnect an H-bridge used to control the electromechanical device from a power supply.
5. Apparatus according to claim 1, wherein the main control unit is configured to enable and/or disable the output of a voltage regulator providing power to the control unit.
6. Apparatus according to claim 1, wherein said electromechanical device comprises a stepper motor.
7. Apparatus according to claim 1, wherein said main control unit is configured to control at least a further element of said apparatus.
8. Apparatus according to claim 1, wherein said motion detector comprises an optical chopper, an emission source and at least one detector.
9. Apparatus according to claim 1, further comprising at least a first reservoir containing a first fluid, and a fluidic channel connected at least to said first reservoir, wherein said electromechanical device is configured to exert a pressure at least on said first fluid in said first reservoir such that said fluid is guided through said fluidic channel.
10. Apparatus according to claim 1, further comprising a drive train, wherein said electromechanical device drives said drive train to exert pressure on said first fluid.
11. Apparatus according to claim 1, further comprising: a second electromechanical device, a second motion detector, wherein said control unit is configured to control said second electromechanical device, wherein said main control unit is configured to provide to said control unit and wherein said second motion detector and said main control unit are configured such that information about the movement of second electromechanical device is provided by said second motion detector at least to said main control unit.
12. Medical device, in particular a portable medical device, for delivering at least one fluid, in particular a drug delivery device, comprising an apparatus according to claim 1.
13. Method for operating an apparatus, in particular an apparatus or medical device according to claim 1, comprising the steps of providing information from a main control unit to a control unit, wherein said control unit and said main control unit are realized with microprocessors, controlling an electromechanical device by means of said control unit, wherein said electromechanical device is a motor, detecting movement of said electromechanical device, and providing information about said movement of said electromechanical device to said main control unit.
14. Method according to claim 13, further comprising the step of providing information about said movement of said electromechanical device to said control unit.
15. Method according to claim 13, wherein said main control unit compares the information provided from said main control unit to said control unit with said information provided from said motion detector to said main control unit.
16. Method according to claim 13, wherein the connection between an H-bridge used to control the electromechanical device and a power supply is interrupted by said main control unit in dependence of said information from said motion detector.
17. Apparatus according to claim 1, wherein said control unit is configured to perform a comparative operation between the control signal sent to said electromechanical device and the information about the movement of said electromechanical device, and wherein said main control unit is configured to compare the information provided by the main control unit with the information about the movement of said electromechanical device, and, in the case of a mismatch between the information provided by the main control unit and the information about the movement of said electromechanical device, said main control unit is configured to overrule the control signal provided by the control unit.
18. A medical device for delivering at least one fluid, said medical device comprising: an electromechanical device, wherein said electromechanical device is a motor, a control unit, a main control unit and a motion detector, wherein: said control unit and said main control unit are realized with microprocessors, said main control unit is configured to provide information regarding control of the electromechanical device to said control unit, and said control unit is configured to provide a corresponding control signal to said electromechanical device to control said electromechanical device, said motion detector and said main control unit are configured such that information about the movement of said electromechanical device is provided by said motion detector to said main control unit and said control unit, said control unit is configured to perform a comparative operation between the control signal sent to said electromechanical device and the information about the movement of said electromechanical device, and said main control unit is configured to compare the information provided by the main control unit with the information about the movement of said electromechanical device, and, in the case of a mismatch between the information provided by the main control unit and the information about the movement of said electromechanical device, said main control unit is configured to overrule the control signal provided by the control unit.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) These as well as other advantages of various aspects of the present invention will become apparent to those of ordinary skill in the art by reading the following detailed description, with appropriate reference to the accompanying drawings, in which:
(2)
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DETAILED DESCRIPTION
(10)
(11) The mechanical movement of the electromechanical device 8 is detected by the motion detector 10, illustrated by the dotted line 9. This motion detector 10 can in particular be an optical detector comprising an optical chopper, an emission source and a detector to encode the light signal into an electrical signal, which can be processed by the main control unit 2 and/or the control unit 4.
(12) Via a connection 12 and an optional connection 14 the motion detector 10 can provide information about the movement of the electromechanical device 8 to the main control unit 2 and (optionally) the control unit 4. The connection 14 to the control unit may be omitted, for example to reduce implementation costs.
(13) As illustrated in
(14) The main control unit 2 can then provide information to the control unit 4 over the connection 6. The control unit 4 provides corresponding information to the electromechanical device, such as a control signal, in order to trigger a corresponding movement of the electromechanical device 8. The motion detector 10 then provides information to the main control unit 2 about the movement of the electromechanical device 8.
(15) In case there is a mismatch between the information provided to the control unit 4 by the main control unit and the information provided by the motion detector 10, the main control unit 2 may react accordingly. This means that the control unit can for example inform the user of the error over the display unit 16. The main control unit 4 may also send further information to the control unit 4 in order to counterbalance the mismatch. This works, for example, if the motor only performed a smaller movement than requested. In case the apparatus is used in a medical device, this may prevent an underdose, example. The main control unit 2 may also interrupt the connection between the control unit 4 and the electromechanical device 8 via the connection 20, illustrated by the dotted line.
(16) A switch 22 is located between the control unit 4 and the electromechanical device 8. This switch is illustrated in the open position. Of course, when the control unit 4 provides information to the electromechanical device, this switch 22 needs to be closed. Thus, in the normal case the switch 22 is closed. In case of an error or a malfunction, for example of the electromechanical device 8 or the control unit 4, the main control unit 2 can trigger the switch 22 to stop the mechanical device 8 from further receiving information from the control unit 4 and thus preventing the electromechanical device 8 from further movement. In case the apparatus is used in a medical device, this might prevent an overdose, for example. The switch can comprise a transistor for electronic switching, for example, but a mechanical switch is possible as well.
(17) Alternatively, the main control unit 2 could also override the control signals of the control unit 4 and provide information to the electromechanical device 8 itself.
(18) The optional connection 14 can also be used to receive information from the motion detector 10, so that an error can also be detected by the control unit 4. In this way, a faster error detection might be realized, though the main control unit 2 has still the possibility of overruling the control unit 4.
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(21) An alternative embodiment may combine the mechanisms shown in
(22)
(23) In the following figures components of a drug delivery device for the delivery of two drugs are described. The use of an apparatus and a method according to the invention is especially advantageous in such medical devices, since an accurate dose delivery of a certain medicament or drug is of great importance, since over and under dosages can be deadly in the worst case. Thus, if a fluid, in particular a medicament or a drug, is delivered by the movement of the electromechanical device 8, it is important to provide a reliable and predictable movement of the electromechanical device 8.
(24)
(25) With reference to
(26)
(27) In this preferred drive train 50, the system comprises an independent electromechanical device 8 in form of motors 70, 86 for each cartridge 58, 60. That is, an independent mechanical driver 66 operates to expel a dose from the first cartridge 58 and an independent mechanical driver 68 operates to expel a dose from the second cartridge 60. In an alternative drive train 50 operating on three different medicaments, three independent mechanical drivers could be provided. The independent mechanical drivers can act under control of motor drivers of a control unit 4 (see
(28) The first independent mechanical driver 66 operates to expel a dose from the first cartridge 58. This first driver 66 comprises a first electromechanical device 8 in form of a motor 70 that is operatively coupled to a first gearing arrangement 72. To energize this motor 70, a connector 74 is provided as a means of electrically connecting to the motor driver. This first gearing arrangement 72 is mechanically linked to a proximal portion of the first telescoping piston rod 76. The first telescoping piston rod 76 is illustrated in a fully extended position having a distal end 78 acting on the stopper 62 of the first cartridge 58.
(29) As this gearing arrangement 72 is driven by the output shaft of the first motor 70, this arrangement 72 rotates the proximal portion 80 of the first telescoping piston rod 76. As this proximal portion 80 of the piston rod 76 is rotated, the second or distal portion 82 of the piston rod 76 is driven in a distal direction.
(30) Preferably, the proximal portion 80 of the telescope piston rod 76 comprises an external thread 84. This thread 84 engages the distal portion 82 which has in integrated nut comprising a short threaded section at a proximal end of the distal portion 82. This distal portion 82 is prevented from rotating via a key acting in a keyway. Such a keyway may pass through the middle of first telescope 76. Therefore, when the first gearbox arrangement 72 causes rotation of the proximal section 80, rotation of the proximal portion 80 acts upon the distal end 78 to thereby drive the distal portion of telescope piston rod to extend along the longitudinal axis.
(31) Moving in this distal direction, the distal end 78 of the second portion 82 of the piston rod 76 exerts a force on a stopper 62 contained within the first cartridge 58. With this distal end 78 of the piston rod 76 exerting a force on the stopper, the user selected dose of the first medicament is forced out of the cartridge 58 and into an attached dispense interface, for example, and then out an attached needle assembly which can allow the user to inject the medicament.
(32) A similar injection operation occurs with the second independent driver 68 when a controller first determines that a dose of a second medicament is called for and determines the amount of this dose. In certain circumstances, the controller may determine that a dose of the second medicament may not be called for and therefore this second dose would be “set” to a “0” dose.
(33) Preferably, motors 70, 86 comprise motors suitable for electronic commutation. Most preferably, such motors may comprise either a stepper motor or a brushless DC motor.
(34) To inject a dose of the primary and secondary medicaments a user will first select a dose of the primary medicament by way of the human interface components on the display 52 (see
(35) When the dose sizes of the first and second medicaments have been established, the motor drivers energize both the first and the second motors 70, 86 to begin the injection process described above.
(36) The piston rods 76, 88 are preferably movable between a first fully withdrawn position (not shown) and a second fully extended portion (as shown in
(37) In one preferred arrangement, both the first and second motors 70, 86 operate simultaneously so as to dispense the user selected dose of the first medicament and the subsequently calculated dose of the second medicament simultaneously. That is, both the first and the second independent mechanical drivers 66, 68 are capable of driving the respective piston rods 76, 88 either at the same or a different time.
(38) One or more of the steps of the injection may be performed automatically, for example controlled by a microcontroller, for example by the control unit 4 or the main control unit 2, such as the step of rewinding the first and/or second piston rod. In an alternative arrangement, the microcontroller, in particular the main control unit 2, may be programmed so that the first and the second independent mechanical drivers 66, 68 may be operated to dispense either the first medicament or the second medicament prior to the other medicament. Thereafter, the second or the primary medicament may then be dispensed. In one preferred arrangement, the secondary medicament is dispensed before the primary medicament.
(39) Preferably both motors 70, 86 may be operated in a reverse direction. This feature may be required in order to allow the piston rods 76, 88 to be moved between a first and a second position.
(40) The first independent mechanical driver 66 illustrated in
(41) As illustrated in
(42) Preferably, as the first and second flags 98a-b pass through the first optical encoder 90, the encoder 90 can send certain electrical pulses to a microcontroller, for example the main control unit 2 or the control unit 4. Preferably, the optical encoder 90 sends two electrical pulses per motor output shaft revolution to the microcontroller. As such, the microcontroller can therefore monitor motor output shaft rotation. This is advantageous to detect position errors or events that could occur during a dose administration step such as jamming of the drive train, incorrect mounting of a dispense interface or a needle assembly, or where there is a blocked needle.
(43) In order to increase the accuracy of the motion detection, it is particularly preferred to provide more than two flags on the motor pinion 92. In combination with a motion detector including two photo detectors, multiple positions during a revolution of motor output shaft can be distinguished, since 4 positions of a flag are registered (both photo detectors, the first photo detector, the second photo detector or none of the photo detectors detect light). With five flags 20 positions during a revolution of motor output shaft can be distinguished.
(44) Preferably, the first pinion 92 comprises a plastic injection molded pinion. Such a plastic injection molded part may be attached to the output motor shaft 94. The optical encoder 90 may be located and attached to a gearbox housing. Such a housing may contain both the first gearing arrangement 72 along with the optical encoder 90. The encoder 90 is preferably in electrical communication with the main control unit 2 potentially via a flexible portion of the PCB. In a preferred arrangement, the second independent mechanical driver 68 illustrated in
(45) The term “drug” or “medicament”, as used herein, means a pharmaceutical formulation containing at least one pharmaceutically active compound,
(46) 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, an enzyme, an antibody or a fragment thereof, a hormone or an oligonucleotide, or a mixture of the above-mentioned pharmaceutically active compound,
(47) 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,
(48) 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,
(49) 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.
(50) 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.
(51) 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.
(52) 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.
(53) Exendin-4 derivatives are for example selected from the following list of compounds:
(54) H-(Lys)4-des Pro36, des Pro37 Exendin-4(1-39)-NH2,
(55) H-(Lys)5-des Pro36, des Pro37 Exendin-4(1-39)-NH2,
(56) des Pro36 [Asp28] Exendin-4(1-39),
(57) des Pro36 [IsoAsp28] Exendin-4(1-39),
(58) des Pro36 [Met(O)14, Asp28] Exendin-4(1-39),
(59) des Pro36 [Met(O)14, IsoAsp28] Exendin-4(1-39),
(60) des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39),
(61) des Pro36 [Trp(O2)25, IsoAsp28] Exendin-4(1-39),
(62) des Pro36 [Met(O)14 Trp(O2)25, Asp28] Exendin-4(1-39),
(63) des Pro36 [Met(O)14 Trp(O2)25, IsoAsp28] Exendin-4(1-39); or
(64) des Pro36 [Asp28] Exendin-4(1-39),
(65) des Pro36 [IsoAsp28] Exendin-4(1-39),
(66) des Pro36 [Met(O)14, Asp28] Exendin-4(1-39),
(67) des Pro36 [Met(O)14, IsoAsp28] Exendin-4(1-39),
(68) des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39),
(69) des Pro36 [Trp(O2)25, IsoAsp28] Exendin-4(1-39),
(70) des Pro36 [Met(O)14 Trp(O2)25, Asp28] Exendin-4(1-39),
(71) des Pro36 [Met(O)14 Trp(O2)25, IsoAsp28] Exendin-4(1-39),
(72) wherein the group -Lys6-NH2 may be bound to the C-terminus of the Exendin-4 derivative;
(73) or an Exendin-4 derivative of the sequence
(74) H-(Lys)6-des Pro36 [Asp28] Exendin-4(1-39)-Lys6-NH2,
(75) des Asp28 Pro36, Pro37, Pro38Exendin-4(1-39)-NH2,
(76) H-(Lys)6-des Pro36, Pro38 [Asp28] Exendin-4(1-39)-NH2,
(77) H-Asn-(Glu)5des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-NH2,
(78) des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-(Lys)6-NH2,
(79) H-(Lys)6-des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-(Lys)6-NH2,
(80) H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-(Lys)6-NH2,
(81) H-(Lys)6-des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39)-Lys6-NH2,
(82) H-des Asp28 Pro36, Pro37, Pro38 [Trp(O2)25] Exendin-4(1-39)-NH2,
(83) H-(Lys)6-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28] Exendin-4(1-39)-NH2,
(84) H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28] Exendin-4(1-39)-NH2,
(85) des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28] Exendin-4(1-39)-(Lys)6-NH2,
(86) H-(Lys)6-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28] Exendin-4(1-39)-(Lys)6-NH2,
(87) H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28] Exendin-4(1-39)-(Lys)6-NH2,
(88) H-(Lys)6-des Pro36 [Met(O)14, Asp28] Exendin-4(1-39)-Lys6-NH2,
(89) des Met(O)14 Asp28 Pro36, Pro37, Pro38 Exendin-4(1-39)-NH2,
(90) H-(Lys)6-desPro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-NH2,
(91) H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-NH2,
(92) des Pro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-(Lys)6-NH2,
(93) H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-(Lys)6-NH2,
(94) H-Asn-(Glu)5 des Pro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-(Lys)6-NH2,
(95) H-Lys6-des Pro36 [Met(O)14, Trp(O2)25, Asp28] Exendin-4(1-39)-Lys6-NH2,
(96) H-des Asp28 Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25] Exendin-4(1-39)-NH2,
(97) H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Asp28] Exendin-4(1-39)-NH2,
(98) H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28] Exendin-4(1-39)-NH2,
(99) des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28] Exendin-4(1-39)-(Lys)6-NH2,
(100) H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28] Exendin-4(S1-39)-(Lys)6-NH2,
(101) H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28] Exendin-4(1-39)-(Lys)6-NH2;
(102) or a pharmaceutically acceptable salt or solvate of any one of the afore-mentioned Exedin-4 derivative.
(103) 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.
(104) 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.
(105) Antibodies are globular plasma proteins (˜150 kDa) that are also known as immunoglobulins which share a basic structure. As they have sugar chains added to amino acid residues, they are glycoproteins. The basic functional unit of each antibody is an immunoglobulin (Ig) monomer (containing only one Ig unit); secreted antibodies can also be dimeric with two Ig units as with IgA, tetrameric with four Ig units like teleost fish IgM, or pentameric with five Ig units, like mammalian IgM.
(106) The Ig monomer is a “Y”-shaped molecule that consists of four polypeptide chains; two identical heavy chains and two identical light chains connected by disulfide bonds between cysteine residues. Each heavy chain is about 440 amino acids long; each light chain is about 220 amino acids long. Heavy and light chains each contain intrachain disulfide bonds which stabilize their folding. Each chain is composed of structural domains called Ig domains. These domains contain about 70-110 amino acids and are classified into different categories (for example, variable or V, and constant or C) according to their size and function. They have a characteristic immunoglobulin fold in which two β sheets create a “sandwich” shape, held together by interactions between conserved cysteines and other charged amino acids.
(107) There are five types of mammalian Ig heavy chain denoted by α, δ, ε, γ, and μ. The type of heavy chain present defines the isotype of antibody; these chains are found in IgA, IgD, IgE, IgG, and IgM antibodies, respectively.
(108) Distinct heavy chains differ in size and composition; α and γ contain approximately 450 amino acids and δ approximately 500 amino acids, while μ and ε have approximately 550 amino acids. Each heavy chain has two regions, the constant region (CH) and the variable region (VH). In one species, the constant region is essentially identical in all antibodies of the same isotype, but differs in antibodies of different isotypes. Heavy chains γ, α and δ have a constant region composed of three tandem Ig domains, and a hinge region for added flexibility; heavy chains μ and ε have a constant region composed of four immunoglobulin domains. The variable region of the heavy chain differs in antibodies produced by different B cells, but is the same for all antibodies produced by a single B cell or B cell clone. The variable region of each heavy chain is approximately 110 amino acids long and is composed of a single Ig domain.
(109) In mammals, there are two types of immunoglobulin light chain denoted by λ and κ. A light chain has two successive domains: one constant domain (CL) and one variable domain (VL). The approximate length of a light chain is 211 to 217 amino acids. Each antibody contains two light chains that are always identical; only one type of light chain, κ or λ, is present per antibody in mammals.
(110) Although the general structure of all antibodies is very similar, the unique property of a given antibody is determined by the variable (V) regions, as detailed above. More specifically, variable loops, three each the light (VL) and three on the heavy (VH) chain, are responsible for binding to the antigen, i.e. for its antigen specificity. These loops are referred to as the Complementarity Determining Regions (CDRs). Because CDRs from both VH and VL domains contribute to the antigen-binding site, it is the combination of the heavy and the light chains, and not either alone, that determines the final antigen specificity.
(111) An “antibody fragment” contains at least one antigen binding fragment as defined above, and exhibits essentially the same function and specificity as the complete antibody of which the fragment is derived from. Limited proteolytic digestion with papain cleaves the Ig prototype into three fragments. Two identical amino terminal fragments, each containing one entire L chain and about half an H chain, are the antigen binding fragments (Fab). The third fragment, similar in size but containing the carboxyl terminal half of both heavy chains with their interchain disulfide bond, is the crystalizable fragment (Fc). The Fc contains carbohydrates, complement-binding, and FcR-binding sites. Limited pepsin digestion yields a single F(ab′)2 fragment containing both Fab pieces and the hinge region, including the H—H interchain disulfide bond. F(ab′)2 is divalent for antigen binding. The disulfide bond of F(ab′)2 may be cleaved in order to obtain Fab′. Moreover, the variable regions of the heavy and light chains can be fused together to form a single chain variable fragment (scFv).
(112) 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's Pharmaceutical Sciences” 17. ed. Alfonso R. Gennaro (Ed.), Mark Publishing Company, Easton, Pa., U.S.A., 1985 and in Encyclopedia of Pharmaceutical Technology.
(113) Pharmaceutically acceptable solvates are for example hydrates.