Patent Description:
Drive units for liquid handling devices may be comparatively complex and costly to manufacture.

It is an object of the present disclosure to provide an improved drive unit for a liquid handling device and/or for a medical device, such as a drug delivery device. Furthermore, it is an object to provide an improved liquid handling device and/or medical device, in particular a drug delivery device.

This object is achieved by the subject matter defined in the independent claim. Advantageous refinements and embodiments are subject matter of the dependent claims.

A drive unit according to the invention is disclosed in claim <NUM>.

One aspect of the present disclosure relates to a drive unit for a liquid handling device, such as a medical device, in particular a drug delivery device. Another aspect of the disclosure relates to a liquid handling device and/or a medical device, in particular a drug delivery device, comprising the drive unit. The device may comprise the drive unit and a liquid handling unit. The liquid handling unit may be secured to the drive unit, for example releasably. The liquid handling may form a disposable item or unit. The drive unit may be reused. The device may be a dispensing device, where liquid is dispensed from the device, and/or a retrieving or suction device, where liquid substance is sucked into the device from the exterior of the device.

It should be noted that, herein, features relating to the drive unit do also apply for the device comprising the drive unit and vice versa. That is to say, if a feature is disclosed in conjunction with the device, for example, it should also be regarded as being disclosed for the drive unit without referencing the other features of the device. Moreover, features discussed in conjunction with different aspects or embodiments may be combined with one another, even if such a combination is not explicitly disclosed.

In an embodiment, the drive unit comprises a drive unit housing and a drive member, which is retained in the drive unit housing and moveable relative to the drive unit housing to drive an operation of the device. The drive member comprises a coupler output portion. The coupler output portion is expediently configured to be operatively connected to a liquid handling unit, e.g. to a coupler input portion of the liquid handling unit. The coupler output portion may have a free end. The liquid handling unit may be part of the device. The coupler output portion may define the interface, e.g. provide one or more mechanical coupling features, for coupling the drive unit to the liquid handling unit. The coupler output portion of the drive member may be formed as a separate part or unitary with the remaining drive member. That is to say, the drive member may have a plurality of parts, e.g. two parts, such as a drive shaft and a coupling member, or be unitary. If the drive member has a plurality of parts, the parts are preferably rigidly connected such that the drive member acts as a single member. When the liquid handling unit is operatively connected to the drive unit, e.g. when the device has been assembled, the coupler output portion may be coupled to the coupler input portion of the liquid handling unit to transfer movement, force and/or torque from the drive member to the liquid handling unit. The coupler output portion may be rotationally and/or axially locked to the coupler input portion, such that movement of the drive member may be transferred from the drive unit to the liquid handling unit. The movement transferred from the drive member to the liquid handling unit may be used to manipulate liquid in the liquid handling unit. The coupler input portion of the liquid handling unit may be a pump driver coupling portion, which provides a coupling between the drive member and a pump driver of the liquid handling unit. The pump driver may be configured to drive a pumping action in the liquid handling unit. The pump driver may be configured to move liquid within the liquid handling unit. When the drive member and the liquid handling unit are operatively connected, the drive unit housing may be, preferably releasably, secured to a liquid handling unit housing of the liquid handling unit.

Further, a drive mechanism is retained in the drive unit housing. The drive mechanism is coupled to or coupleable to the drive member via a mechanism interface. The drive mechanism is configured to transfer a driving force or torque from the mechanism to the drive member. The transfer of the force or torque may occur via the mechanism interface. The drive member may, for example, be a drive shaft or comprise a drive shaft.

The drive unit, furthermore, comprises a sealing member. The sealing member is preferably provided to establish a sealed interface with the drive member. The sealing member may sealingly engage the drive member. For example, the sealing member may have a sealing lip, which engages the drive member to provide a sealed interface with the drive member. The sealed interface may define or limit a sealed section of an interior of the drive unit housing. The coupler output portion is expediently arranged outside of the sealed section. In this way, it may provide the interface to the liquid handling unit. The mechanism interface between drive member and drive mechanism is preferably arranged within the sealed section. Not only the mechanism interface but the entire drive mechanism and, if required, an energy or power source for providing energy to drive the drive mechanism may be provided in the drive unit housing and, particularly, in the sealed section. By providing the sealing member, which establishes a sealed interface with the drive member, it is ensured that elements of the drive unit, which are arranged in the sealed section of the drive unit housing, are protected against environmental influences, such as moisture, dirt, and/or dust. The sealed interface may be moisture-tight, water-tight, water jet-tight, and/or dust-tight.

Thus, that element, which transmits movement to an element in the liquid handling unit, i.e. the drive member, is guided from the sealed section of the drive unit housing to the outside of the sealed section across the sealing member and is available to provide a, preferably mechanical, interface to the liquid handling unit. The remaining portions of the interior of the drive unit housing may be sealed properly.

In an embodiment, the drive member is moveable, e.g. axially and/or rotationally, relative to the sealing member. The drive member may be, e.g. axially, moveable relative to the sealing member from a first position to a second position and/or vice versa. The drive member may be in the second position, when the coupler output portion is operatively connected to the coupler input portion of the liquid handling unit. The drive member may be in the first position, when the entire liquid handling unit and/or its coupler input portion is disconnected from the drive unit. When the drive unit is being operatively coupled to the liquid handling unit, the drive member may be moved away from the first position towards the second position. In the second position, the drive unit and the liquid handling unit may be coupled.

Accordingly, the drive member may be axially moveable when the coupling to said liquid handling unit is being established. This movement may be towards the sealing member as seen from the coupler output portion. Consequently, in the second position, the section of the drive member which is arranged in the sealed section of the drive unit housing may be longer than the one which is arranged in the sealed section in the first position.

In an embodiment, the drive unit comprises a biasing mechanism which is configured to bias the drive member into or towards the first position, e.g. when it is in the second position. Thus, the first position may be the standard position of the drive member, particularly when it is not operatively connected to a liquid handling unit. When the liquid handling unit is disconnected from the drive unit, the drive member may be moved back towards or into the first position by the biasing mechanism starting from the second position. The biasing mechanism may comprise a spring, e.g. a compression spring. The spring may be deformed during the movement from the first position into the second position. The biasing mechanism may be arranged in the sealed section of the drive unit housing.

In an embodiment, the mechanism interface between the drive member and the drive mechanism is a releasable interface. In the first position of the drive member relative to the housing and/or the sealing member, the mechanism interface may be released. Thus, in this position, drive member and drive mechanism may be decoupled. Therefore, when the liquid handling unit is disconnected from the drive unit, the drive member, which then may be in the first position, might be exposed to manipulations by the user of the device, e.g. a patient. If the mechanism interface is not established when the liquid handling unit is disconnected from the drive unit the user may manipulate the drive member without the risk of transmitting manipulation forces or torque to the drive mechanism, as the coupling between the drive member and the drive mechanism is released. Thus, the risk of the drive mechanism being damaged by the user is decreased, if the mechanism interface is released when no liquid handling unit is operatively connected to the drive unit. In the second position, the mechanism is expediently established, i.e. the drive mechanism and the drive member are operatively coupled to transfer force and/or torque between one another, expediently from the drive mechanism to the drive member.

In an embodiment, the sealing member is secured to the drive unit housing. The sealing member may be axially and/or rotationally secured to the drive unit housing. Accordingly, axial and/or rotational movement of the sealing member relative to the drive unit housing may be prevented. Consequently, the sealing member may have a securing section, where it is secured to the drive unit housing. The sealing member may furthermore have a sealing section, where it interfaces with the drive member. The sealing section may be radially offset, e.g. inwardly, relative to the securing section. The sealing section and the securing section may overlap axially. The drive member may extend through the sealing section, e.g. through an opening delimited by the sealing section circumferentially.

In an embodiment, the drive member is configured to rotate and/or move axially with respect to the sealing member during operation. For example, when the drive member is in the second position, it may be axially moveable and/or rotatable relative to the sealing member and/or the drive unit housing during operation, for example to move liquid within the liquid handling unit. The sealing member may be engaged with the drive member while the drive member moves during operation. Thus, the sealed interface is expediently also active during operation of the drive unit.

In an embodiment, the sealing member defines a passage, e.g. an opening. The drive member may extend through the passage.

In an embodiment, the section of the drive member which travels along the sealing member during the movement between the first and second section may have a constant outer diameter. At least this section of the drive member may have a cylindrical outer shape.

In an embodiment, the drive member comprises at least two sections with different outer diameters, e.g. a section of greater outer diameter and a section of smaller outer diameter. For example, a first section may have a greater outer diameter than a second section. The sealing member may engage the section of smaller outer diameter of the drive member, e.g. in the first position and/or the second position. This may be true during any axial relative position between sealing member and drive member during operation of the drive unit. The section of greater outer diameter may be arranged outside of the sealed section, e.g. in the first position and/or the second position. The section of the drive member which travels along the sealing member during the movement between the first and second position may have a constant outer diameter. This section may be cylindrical. The section with greater outer diameter may be arranged outside of the sealed section, e.g. in the first and in the second position. Accordingly, the contact area between the sealing member and the drive member may kept small, which may have advantages with respect to frictional losses during operation, when the drive member is in the first position, and/or with respect to the forces required for moving the drive member from the first position into the second position. The section with greater outer diameter may be part of the coupler output portion.

In an embodiment, the sealing member circumferentially engages the drive member. Accordingly, the sealed interface may extend circumferentially, e.g. ring-like, around the drive member.

In an embodiment, the sealing member is an elastic seal. Accordingly, the sealing member may be elastically deformable, in particular at least in a sealing section, which interacts with the drive member or in its entirety. The sealing member may be a rubber seal, for example, or comprise a sealing section of rubber. Elastic seals are particularly suitable to provide tightly sealed interfaces. If the sealing member is elastically deformable, the elastic restoring force which tends to re-establish the non-deformed shape of the sealing member may be used to enhance the sealing efficiency of the sealing member.

In an embodiment, the sealing member is a radial shaft seal. Radial shaft seals are particularly advantageous to provide tightly sealed interfaces, in particular with low frictional losses when the drive member moves relative to the sealing member while the sealed interface is established. The drive member section interacting with the sealing member may be a shaftshaped section.

In an embodiment, the sealing member engages a radially facing surface of the drive member.

In an embodiment, the sealed interface provided by the sealing member is established in the first position and in the second position. Thus, the sealing may be effective during operation, when the drive unit is operatively coupled to a liquid handling unit and also when no liquid handling unit is provided.

In an embodiment, the sealing member engages the drive member, in particular sealingly, in the first position and/or in the second position. Thus, the sealed interface may be established in both positions.

According to the invention, the drive unit is configured such that a tightness of the sealed interface is different in the first position and in the second position. Preferably, the sealed interface is tighter in the first position than in the second position. Consequently, when the drive unit is not operatively coupled to the liquid handling unit, i.e. when the drive unit is more exposed to external influences potentially, as the liquid handling unit is not present, the sealed section may be sealed more tightly. When the seal or sealed interface is tighter, a sealing force or contact force between the sealing member and the drive member may be greater than when the sealed interface is less tight. Thus, in the first position, the sealing force or contact force may be greater than in the second position, if the sealed interface is tighter in the first position than in the second position, or vice versa, if the sealed interface in the second position is tighter.

Alternatively and not according to the invention, in the first and in the second position, the sealed interface may have the same tightness.

In an embodiment, the drive unit, e.g. the drive member, comprises a transfer member. The transfer member may transfer a force to the sealing member. The force may be a biasing force, e.g. originating from the biasing mechanism such as a spring force. The force may be transferred to the sealing member in the first position, preferably only in the first position, and/or not transferred to the sealing member in the second position. The force may be used to increase the tightness of the seal. Accordingly, the force may be used to increase a sealing force between the sealing member and the drive member or the contact force between the sealing member and the drive member. To increase the sealing force, the direction of the biasing force may be changed. For example, an axially directed biasing force may be converted into a radially, preferably inwardly, directed force, which may increase the force and/or the pressure which the sealing member exerts onto the drive member.

If the transfer member is part of the drive member, it is facilitated that the biasing force of the biasing mechanism can be used not only to move the drive member into the first position but also, when it is in the first position, to increase the sealing or contact force. Thus, in the first position, there may be a remaining bias in the biasing mechanism such that the first position may be defined by the sealing member, as the interface, which secures the sealing member in the drive unit, may counteract the remaining biasing force which still tends to move the drive member beyond the first position. Thus, in the first position, there may be a biasing force which tends to move the drive member away from the second position and/or the first position.

The transfer member may be adjusted and configured to engage an outer surface of the sealing member. The transfer member may transfer an axially directed force to the sealing member. The transfer member may have a sloped surface and/or the sealing member may have a sloped surface. By means of the oblique or sloped surface, the axial force may be converted into a radially, preferably inwardly, directed force to increase the sealing force or contact force between the sealing member and the drive member. Thus, by way of the oblique or sloped surface, an axially directed force may be converted into a radially directed force. Other conversion mechanisms may also be applied as feasible.

In an embodiment, in the first position a first section of the drive member is engaged by the sealing member. In the second position a second section of the drive member is engaged by the sealing member. The first section and the second section may have different outer diameters. The first section may have a greater outer diameter than the second section. Thus, if the sealing member and/or the portion thereof interacting with the drive member is elastically deformable, the elastic restoring force, e.g. in the radial inward direction, may be greater in the first position than in the second position, as the elastic deformation is increased on account of the greater diameter in the first position. In this way, in the first position the tightness may be increased by means of the greater outer diameter of the drive member in the first section.

Alternatively, the first section and the second section may have equal outer diameters. This facilitates provision of a sealed interface which has the same tightness in the first position and in the second position, where a sealed interface which has the same tightness in the first position and in the second position is not according to the invention.

In an embodiment, the drive mechanism is electrically driven or electrically operated or operable. The drive mechanism is expediently arranged and/or retained in the drive unit housing such as in the sealed section thereof.

In an embodiment, the drive mechanism comprises a motor, in particular, an electric motor. The motor is expediently arranged in the drive unit housing such as in the sealed section thereof.

In an embodiment, the drive unit comprises a power source, e.g. an electrical power source. The power source may be arranged in the drive unit housing. The power source may be operatively, e.g. conductively, connected to the drive mechanism to provide power for moving the drive member relative to the housing and/or the sealing member. For example, the power source is a battery. The battery may be replaceable. The power source is expediently arranged in the sealed section of the drive unit housing.

In an embodiment, the drive unit is reusable. Thus, the drive unit may be used in conjunction with a plurality of liquid handling units. This is particularly efficient, if rather expensive components, such as a drive mechanism, e.g. an electronically controlled drive mechanism, a motor, and/or a power source are arranged in the drive unit housing.

In an embodiment the liquid handling unit comprises a pump mechanism. The pump mechanism may be operable to move liquid from and/or into a reservoir. The reservoir may be comprised by the liquid handling unit. The reservoir may comprise a liquid and/or may be adapted to receive liquid. The pump mechanism may comprise a pump driver. The pump driver may be coupled to the coupler output portion of the drive member of the drive unit, particularly via the coupler input portion of the liquid handling unit. The coupler input portion may be provided on the pump driver or at a part connected to the pump driver, e.g. rigidly connected thereto. When the drive unit and the liquid handling unit are operatively connected, movement of the drive member of the drive unit may be transferred to the pump driver. Movement of the pump driver, e.g. relative to the liquid handling unit housing, may be used to drive a pumping action. If the device is a dispensing device, the pump mechanism may move liquid from the reservoir to an outlet of the device. If the device is a retrieving device, the pump mechanism may move liquid from an inlet of the device into the reservoir. The pump mechanism may comprise a pump chamber. The pump driver or at least a section thereof may be arranged in the pump chamber. Movement of the pump driver relative to the pump chamber may cause movement of liquid in the liquid handling unit.

In an embodiment, the liquid handling unit comprises a liquid guiding conduit. The liquid guiding conduit may have a liquid passage end, e.g. an inlet or an outlet. The inlet or the outlet may form the inlet or the outlet of the device. The liquid guiding conduit may be fluidly connected to the reservoir. The pump chamber, within which a pumping portion of the pump driver may be moveably arranged, is preferably arranged in the liquid guiding conduit, particularly between the liquid passage end and the reservoir as seen along the flow path between the reservoir and the liquid passage end. Accordingly, the pump driver may govern the movement of liquid along the liquid guiding conduit, e.g. for dispensing liquid from the reservoir through the liquid passage and/or for retrieving liquid from an object, e.g. the body of a mammal, through the liquid passage end.

In an embodiment, the liquid handling unit is releasably connected to the drive unit, e.g. via a snap fit or another suitable connection. Thus, the liquid handling unit may be detached from the drive unit and disposed of and the drive unit may be reused in conjunction with a different liquid handling unit. Although the liquid handling unit comprises the pump mechanism and the reservoir, it may nevertheless be disposed of after use in the proposed concepts as the pump mechanism may be comparatively easy and cost effective to manufacture such that the costs of the liquid handling unit with an integrated pump mechanism are still tolerable. Moreover, if the liquid handling unit is disposable, the pump mechanism and/or the associated conduit can be disposed as well and the risk that the pump mechanism and the conduit are contaminated is reduced as opposed to a device where the pump mechanism were reused.

In an embodiment, the liquid handling unit comprises a liquid handling unit housing. The reservoir and/or the pump mechanism, in particular the pump driver, may be arranged and/or retained in the liquid handling unit housing. The liquid guiding conduit may be arranged or defined in the liquid handling unit housing.

In an embodiment, in the device, the liquid handling or guiding functionality is restricted to the liquid handling unit and the drive functionality, preferably the entire drive functionality, for moving liquid within the liquid handling unit is provided by the drive unit. Contact between an element, preferably all elements, of the drive unit and the liquid may be prevented during operation of the device.

In an embodiment, the device comprises a mounting surface. The mounting surface may be configured for mounting the device to a body of a mammal, e.g. a human, for example a patient, which should be treated by a drug retained in the reservoir. The device may be fixed to the skin of the mammal via the mounting surface. The mounting surface may be a surface of the liquid handling unit or a surface of the drive unit. If the mounting surface is a surface of the liquid handling unit a fixing means to secure the device to the body may be exchanged together with the liquid handling unit. If the mounting surface is provided on the drive unit, the liquid handling unit may be exchanged, while the drive unit is still mounted on the body, e.g. at a pre-defined location, which may have been selected by a physician for example.

In an embodiment, the mounting surface is provided with an adhesive. Via the adhesive, the device may be secured to the body.

In an embodiment, the device is designed to stay connected to the body for a longer period of time, e.g. days or weeks.

In an embodiment, the device is a patch pump. Consequently, the device comprises a pump mechanism and can be applied like a patch on an object or a surface such as on a body of a mammal.

In an embodiment, the device is a drug delivery device. A liquid drug may be retained in the reservoir. Thus, the liquid drug may be dispensed from the reservoir and from the device by means of the drive unit.

In an embodiment, the device comprises an actuator, which, when operated, triggers an operation of the device, e.g. a delivery operation to dispense liquid, such as a dose delivery operation, e.g. for dispensing a dose, i.e. a selected sub-quantity of the drug contained in the reservoir, of drug from the device. The actuator may be user operable. The actuator may be provided on the drive unit. For example, the actuator may be a button, which can be touched by a user, e.g. in order to trigger a dispensing action for dispensing liquid from the reservoir. Of course, with respect to the exterior, the actuator may be sealed, such that the seal of the sealed section of the interior of the housing is not jeopardized.

In an embodiment, the end passage of the liquid handling unit is provided by a needle or needle tip and/or a connector, which is either provided to be, e.g. releasably or permanently, connected with a needle, such as a threaded connector, or a tube, such as a luer connector, which connects the liquid guiding conduit to a tubing. If no needle connector is provided, the needle may be integrated into the liquid handling unit as an integral part. The needle may then be disposed of together with the liquid handling unit.

Further features, advantages and expediencies of the present disclosure will become apparent from the following description of the exemplary embodiments in conjunction with the drawings.

Identical elements, elements of the same kind and identically acting elements may be provided with the same reference numerals in the figures.

<FIG> shows an exemplary embodiment of a liquid handling device, particularly a medical device. The depicted embodiment is a drug delivery device <NUM>, which is designed to deliver a drug or a medicament. Of course, the disclosed concepts can be applied to other liquid handling or medical devices as well, be it liquid dispensing devices or liquid retrieving devices.

The drug delivery device <NUM> comprises a drive unit <NUM> and a liquid handling unit <NUM>. The drive unit <NUM> and the liquid handling unit <NUM> are releasably attached or secured to one another. The liquid handling unit <NUM> may be a disposable unit, which may be replaced with a new one, for example because the drug or medicament in the liquid handling unit has been used up. The drive unit <NUM> is expediently a reusable unit, which can be used together with several liquid handling units. The releasable connection may be effected by a snap fit connection, a press fit connection, a Velcro connection, a releasable adhesive connection or the like. The specific connection means between the drive unit <NUM> and the liquid handling unit <NUM> is not explicitly illustrated. The liquid handling unit <NUM> comprises a liquid unit housing <NUM>. The drive unit <NUM> comprises a drive unit housing <NUM>. Mating connection means, not explicitly illustrated, may be provided on end faces of the liquid handling unit housing <NUM> and the drive unit housing <NUM>, which face one another, and, when in mechanical cooperation, attach the liquid handling housing <NUM> releasably to the drive unit housing <NUM>.

The liquid handling unit <NUM> comprises a liquid guiding conduit <NUM>. Along the liquid guiding conduit <NUM>, liquid may be guided in the liquid handling unit during operation of the device <NUM>. The conduit <NUM> may be defined in the housing, e.g. by providing a channel structure in the housing as depicted, or, alternatively, by a tube system arranged in the housing, if applicable in combination with a channel structure. The conduit <NUM> has at least two different sections, a first section <NUM> and a second section <NUM>. In the flow path between the two sections <NUM> and <NUM> a pump chamber <NUM> is arranged, which is in fluid communication with the section <NUM> and the section <NUM> of the conduit <NUM>. The sections <NUM> and <NUM> preferably extend away from different openings which provide access to the pump chamber. Within the pump chamber <NUM>, a pump portion <NUM>, e.g. a pump head, of a pump driver <NUM> may be arranged. The pump driver <NUM> is movable relative to the pump chamber <NUM> to move fluid along the conduit e.g. from the first section <NUM> into the second section <NUM> and/or vice versa. The pump driver <NUM> may, for example, be rotatable in the pump chamber <NUM>. The pump driver <NUM> may be a rotor. The walls of the chamber may serve as a stator of a rotationally operating pump. The stator may cooperate with the rotor to provide a pumping action when the pump driver <NUM> is rotated relative to the pump chamber and/or the liquid handling unit housing.

The liquid handling unit <NUM> further comprises a reservoir <NUM>. The section <NUM> is in fluid communication with the reservoir <NUM>. Particularly, the section <NUM> is arranged in the flow path between the reservoir <NUM> and the pump chamber <NUM>. The section <NUM> is in fluid communication with a liquid passage end <NUM> or open end of the conduit <NUM>.

In <FIG> the end of the conduit <NUM> is highlighted by reference <NUM>. The section <NUM> is arranged in the flow path between the pump chamber <NUM> and the end <NUM>. The end <NUM> may for example be formed by an opening in the liquid handling unit housing <NUM>. The end <NUM> may either be provided with a connector (not explicitly shown) such as a tube connector for fluidly connecting a tube to the conduit <NUM> of the liquid handling unit, e.g. a Luer connector, and/or a needle connector for, e.g. releasably, connecting a needle unit to the housing and fluidly to the conduit <NUM>. Alternatively, a needle <NUM> may be provided in the liquid handling unit <NUM> in fluid communication with the conduit, in particular section <NUM> thereof, as depicted. The needle <NUM> may form an integral part of the liquid handling unit, i.e. it is not designed to be detached from the liquid handling unit.

Through the end <NUM> liquid may be dispensed from the liquid handling unit housing <NUM>. If a needle is provided as is depicted by needle <NUM>, the needle may penetrate the skin of a user, e.g. a human patient. Through the needle <NUM>, liquid, e.g. a drug, may be dispensed into the body of a mammal or retrieved therefrom, e.g. blood, when the device is operated.

The reservoir <NUM>, in case of a drug delivery device as liquid handling device, expediently comprises a liquid drug <NUM> or a medicament.

The drug container may be, e.g., a cartridge, syringe, reservoir, or other solid or flexible vessel configured to provide a suitable chamber for storage (e.g., short- or long-term storage) of one or more drugs. In some instances, the drug container may be or may include a dual-chamber cartridge configured to store two or more components of the pharmaceutical formulation to-be-administered (e.g., an API and a diluent, or two different drugs) separately, one in each chamber. In such instances, the two chambers of the dual-chamber cartridge may be configured to allow mixing between the two or more components prior to and/or during dispensing into the human or animal body.

The drugs or medicaments contained in the drug delivery devices as described herein can be used for the treatment and/or prophylaxis of many different types of medical disorders. Examples of disorders include, e.g., diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, thromboembolism disorders such as deep vein or pulmonary thromboembolism. Further examples of disorders are acute coronary syndrome (ACS), angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis and/or rheumatoid arthritis. Examples of APIs and drugs are those as described in handbooks such as Rote Liste <NUM>, for example, without limitation, main groups <NUM> (antidiabetic drugs) or <NUM> (oncology drugs), and Merck Index, 15th edition.

Examples of APIs for the treatment and/or prophylaxis of type <NUM> or type <NUM> diabetes mellitus or complications associated with type <NUM> or type <NUM> diabetes mellitus include an insulin, e.g., human insulin, or a human insulin analogue or derivative, a glucagon-like peptide (GLP-<NUM>), GLP-<NUM> analogues or GLP-<NUM> receptor agonists, or an analogue or derivative thereof, a dipeptidyl peptidase-<NUM> (DPP4) inhibitor, or a pharmaceutically acceptable salt or solvate thereof, or any mixture thereof. As used herein, the terms "analogue" and "derivative" refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, by deleting and/or exchanging at least one amino acid residue occurring in the naturally occurring peptide and/or by adding at least one amino acid residue. The added and/or exchanged amino acid residue can either be codable amino acid residues or other naturally occurring residues or purely synthetic amino acid residues. Insulin analogues are also referred to as "insulin receptor ligands". In particular, the term "derivative" refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, in which one or more organic substituent (e.g. a fatty acid) is bound to one or more of the amino acids. Optionally, one or more amino acids occurring in the naturally occurring peptide may have been deleted and/or replaced by other amino acids, including non-codeable amino acids, or amino acids, including non-codeable, have been added to the naturally occurring peptide.

Examples of insulin derivatives are, for example, B29-N-myristoyl-des(B30) human insulin, Lys(B29) (N- tetradecanoyl)-des(B30) human insulin (insulin detemir, Levemir®); 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-gamma-glutamyl)-des(B30) human insulin, B29-N-omega-carboxypentadecanoyl-gamma-L-glutamyl-des(B30) human insulin (insulin degludec, Tresiba®); B29-N-(N-lithocholyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(ω-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(ω-carboxyheptadecanoyl) human insulin.

Examples of GLP-<NUM>, GLP-<NUM> analogues and GLP-<NUM> receptor agonists are, for example, Lixisenatide (Lyxumia®), Exenatide (Exendin-<NUM>, Byetta®, Bydureon®, a <NUM> amino acid peptide which is produced by the salivary glands of the Gila monster), Liraglutide (Victoza®), Semaglutide, Taspoglutide, Albiglutide (Syncria®), Dulaglutide (Trulicity®), rExendin-<NUM>, CJC-<NUM>-PC, PB-<NUM>, TTP-<NUM>, Langlenatide / HM-11260C, CM-<NUM>, GLP-<NUM> Eligen, ORMD-<NUM>, NN-<NUM>, NN-<NUM>, NN-<NUM>, Nodexen, Viador-GLP-<NUM>, CVX-<NUM>, ZYOG-<NUM>, ZYD-<NUM>, GSK-<NUM>, DA-<NUM>, MAR-<NUM>, MAR709, ZP-<NUM>, ZP-<NUM>, TT-<NUM>, BHM-<NUM>. MOD-<NUM>, CAM-<NUM>, DA-<NUM>, ARI-<NUM>, ARI-<NUM>, Exenatide-XTEN and Glucagon-Xten.

An examples of an oligonucleotide is, for example: mipomersen sodium (Kynamro®), a cholesterol-reducing antisense therapeutic for the treatment of familial hypercholesterolemia.

The term antibody also includes an antigen-binding molecule based on tetravalent bispecific tandem immunoglobulins (TBTI) and/or a dual variable region antibody-like binding protein having cross-over binding region orientation (CODV).

Those of skill in the art will understand that modifications (additions and/or removals) of various components of the APIs, formulations, apparatuses, methods, systems and embodiments described herein may be made.

The reservoir <NUM> may be defined by a reservoir chamber within the liquid handling unit housing <NUM> and delimited by the walls of the housing, where the reservoir chamber is filled with liquid, as depicted, or, alternatively, may be a separate component, such as a cartridge or a bag or another, e.g. prefilled, container, which is fluidly connected to the conduit <NUM> during manufacture of the liquid handling unit <NUM>.

The pump driver <NUM> is expediently permanently retained in the liquid handling unit housing <NUM>. Therefore, if the liquid handling unit <NUM> is disposed, the pump driver is disposed as well. Thus, all parts of the device <NUM>, which contact, move, and guide liquid during operation of the device may be disposed, in particular together with the liquid handling unit <NUM>.

The liquid handling unit <NUM> furthermore comprises a coupler input portion or input coupler <NUM>. The coupler input portion <NUM> may be provided to establish a mechanical interface to the drive unit. The coupler input portion may be operatively connected to the pump driver <NUM>. The coupler input portion may be formed by a portion of the pump driver or another member of the liquid handling unit, which is operatively connected to the pump driver, e.g. rotationally and/or axially locked to the pump driver <NUM>. Via the coupler input portion force or torque may be transferred from the drive unit <NUM> to the pump driver <NUM> in order to move the pump driver to provide a pumping action.

The drive unit <NUM> comprises a drive member <NUM>. The drive member <NUM> is moveably retained in the drive unit housing <NUM>. The drive unit <NUM> is configured to move the drive member <NUM> in order to transfer forces or torque to the pump driver <NUM>. The drive member comprises a coupler output portion <NUM>. As depicted in <FIG>, the coupler output portion <NUM> of the drive member is operatively and preferably mechanically coupled to the coupler input portion <NUM> of the liquid handling unit <NUM>. For example, the coupler output portion <NUM> and the coupler input portion <NUM> may be coupled by a splined coupling so that, when coupled, they are rotationally interlocked and rotation of the drive member <NUM> is transferred to the pump driver <NUM> via the coupler input portion <NUM> to rotate the pump driver relative to the liquid handling unit housing <NUM> in the pump chamber <NUM>. Alternatively or additionally, if the pump driver <NUM> performs axial movement, e.g. only axial movement or axial and rotational movement, relative to the pump chamber <NUM>, the drive member <NUM> may move axially relative to the drive unit housing <NUM>, e.g. only axially or axially and rotationally as the case may be.

As depicted in <FIG> schematically, the drive unit <NUM> comprises a sealing member <NUM>. The sealing member <NUM> is in sealing engagement with the drive member <NUM>, e.g. it abuts the drive member <NUM>. The drive member <NUM> extends through the sealing member. A radially facing surface of the drive member is contacted by the sealing member <NUM> to establish the sealed interface. The sealed interface may be provided along the entire circumference of the drive member <NUM>.

The drive member <NUM> may have portions of different outer diameters. For example, the portion <NUM> of the drive member which is arranged to abut the sealing member <NUM> may have a radial dimension, e.g. an outer diameter, which is less than the one of the coupler output portion <NUM> of the drive member <NUM>. The portion <NUM> may have a cylindrical external surface. Portion <NUM> may be formed shaft-like.

The sealing member <NUM> may delimit or define a sealed interior <NUM> or sealed section of the interior of the drive unit housing <NUM>. As the interface to the exterior is sealed via the sealing member <NUM>, environmental influences like moisture, water and/or durst are prevented from reaching the interior of the drive unit housing and, consequently, more sensible components of the drive unit may be arranged in this section.

As the portion <NUM> has a reduced diameter, frictional losses during rotation and/or axial movement of the drive member <NUM> along the sealing member <NUM> may be kept reasonable, on account of a contact surface between the drive member and the sealing member which is smaller as compared to the outer surface of the coupler output portion <NUM>, for example. The outer diameter of portion <NUM> may be less than or equal to <NUM>. 3D, <NUM>,2D, <NUM>. 15D, or <NUM>. 1D, where D is the outer diameter of another portion of the drive member, e.g. a portion outside of the sealed section such as the coupler output portion <NUM>. D may be the maximum outer diameter of the drive member <NUM> and/or the coupler output portion <NUM>.

Within the sealed interior section <NUM> of the drive unit housing <NUM>, one or more other elements of the drive unit may be arranged. The elements in the interior may include: a drive mechanism, e.g. comprising a motor <NUM>, a power source <NUM>, such as a battery, and/or a control unit <NUM>, such as an electronic control unit.

The drive member <NUM> may extend through the sealing member <NUM> and thus provide an exterior interface for the drive unit while the other elements are protected in the sealed interior <NUM>. The motor <NUM> may be an electrically operated motor. The power source <NUM> may provide the electrical power to operate the motor <NUM> to drive movement of the drive member <NUM> relative to the drive unit housing <NUM> and/or the sealing member <NUM>. The control unit <NUM> may be operatively and/or conductively connected to the power source <NUM> and/or the motor <NUM> to control operation of these elements and/or control the power supply from the power source to the motor.

Between the drive mechanism and the drive member a mechanism interface <NUM> may be provided. Via the mechanism interface, which is preferably established in the sealed interior section <NUM>, the driving force or torque may be transferred from the drive mechanism to the drive member <NUM>, e.g. via a moving shaft, e. g a rotating shaft, which is coupled to the drive member in the sealed interior <NUM> to generate an, e.g. rotational, movement of the drive member <NUM> during operation of the device <NUM>. The movement of the drive member <NUM> may be transferred to the pump driver <NUM> via the coupling established between the coupler output portion <NUM> of the drive unit <NUM> and the coupler input portion <NUM> of the liquid handling unit <NUM>.

The drive unit <NUM> comprises an actuator <NUM>, e.g. a button. The actuator may be actuatable by a user, for example to trigger a dispensing action for delivering drug retained in the reservoir <NUM> from the device. A user interface of the actuator may be accessible from the exterior of the drive unit housing. The actuator may be operatively connected to the control unit <NUM>. Actuation of the actuator may cause the control unit <NUM> to operate the drive mechanism such that the pump driver <NUM> can move within the pump chamber <NUM>. If there is a path of fluid communication along the actuator to the interior of the drive unit housing, this path is expediently sealed such that the sealing of the sealed interior is maintained.

The depicted device <NUM> may be a patch pump. A patch pump is a device, which can be attached to the skin of a user and stays there for an extended period of time, e.g. for days or weeks. If the user recognizes that a delivery of medicament is required, he may, preferably manually, actuate the dispensing action, e.g. via the actuator. As opposed to closed-loop systems, which may be used as artificial pancreas for delivering insulin, patch pumps are less sophisticated, as no sensors are needed which measure the glucose level, for example. However, patch pumps still may be useful to provide medicament to the patient by means of self-administration.

A fixing surface <NUM>, which is provided to be attached to the user, may be provided at the drive unit <NUM>, for example on that surface of the drive unit <NUM>, which is opposite of the liquid handling unit <NUM> as depicted. Alternatively, the fixing surface may be provided on the liquid handling unit, such as on that surface, which faces away from the drive unit (not shown). Moreover, a portion of the fixing surface may be provided on each of the drive unit <NUM> and the liquid handling unit <NUM>. Therefore, the fixing surface may be provided at various places of the device. However, only one region is highlighted in <FIG>, i.e. the one on the drive unit, where the fixing surface <NUM> is shown. The fixing surface may be provided with an adhesive. The same holds for the remaining fixing surfaces mentioned above, such that the device <NUM> may be adhesively attached to the skin of a user. If the device <NUM> is worn by the user at the user's body for an extended period of time, it is particularly expedient to seal the interior of the drive unit, for example to avoid that moisture, such as when the user takes a shower, dust or other dirt can enter the interior of the drive unit housing <NUM>.

The sealing member <NUM> provides the sealed interface with the drive member <NUM> when the liquid handling unit <NUM> is attached to the drive unit <NUM> and also when it is detached. The drive member is in different axial position relative to the sealing member <NUM> when the liquid handling unit is attached and when it is detached.

In the following, several embodiments, which employ a sealing member <NUM>, are explained based on sectional views of portions of the device <NUM> shown in <FIG>. One embodiment is discussed in conjunction with <FIG>, another one in conjunction with <FIG>, still another one in conjunction with <FIG>, <FIG> and yet another one in conjunction with <FIG>.

In <FIG>, there is shown a section of the device as depicted in <FIG>. In particular, the section around the sealing member <NUM> is shown. <FIG> shows the section of the drive unit <NUM> of <FIG>, when no liquid handling unit <NUM> is connected operatively to the drive unit <NUM>.

As can be seen, the drive member <NUM> comprises a drive member interface portion <NUM> or member. The drive mechanism comprises a drive mechanism interface member <NUM>. The drive mechanism interface member is coupled to a drive mechanism member <NUM>, e.g. a shaft, which may be coupled to the motor and be driveable by the motor. At least in the position depicted in <FIG>, when the liquid handling unit is attached, i.e. in the second position of the drive member, the mechanism interface <NUM> is established. The mechanism interface couples the drive member to the drive mechanism or motor which is not explicitly shown in the figure. When the mechanism interface <NUM> is established, the drive member and the interface member may be rotationally locked to one another, e.g. by mating teeth of the interface portion <NUM> and the interface member <NUM> engaging. Thus, in the second position depicted in <FIG>, the drive member is operatively connected to the interface member <NUM> to transfer rotational movement from the drive mechanism to the drive member and the coupler output portion <NUM> thereof, which causes rotation of the coupler input portion <NUM> of the liquid handling unit <NUM> and, accordingly, of the pump driver as is indicated by the arrows. In the position in <FIG>, i.e. the first position, the interface member <NUM> may be operatively disconnected from the drive member. Alternatively, there may be an operative connection, i.e. the mechanism interface may be established also in the first position of the drive member <NUM> relative to the sealing member (see <FIG>). However, if the drive member and the interface member <NUM> are operatively disconnected in the first position, i.e. the mechanism interface is not established, a manipulation of the coupler output portion <NUM> is not transferred to the elements of the drive mechanism in the sealed interior <NUM>. This may be advantageous.

As is apparent from the figures, preferably within the sealed section <NUM> of the interior of the drive unit housing <NUM>, a biasing mechanism is provided, which comprises a spring <NUM>, e.g. a compression spring. The biasing mechanism biases the coupler outer portion <NUM> and/or the drive member <NUM> to the position in <FIG> (first position) when the drive member is in the position depicted in <FIG> (second position). The spring <NUM> may be retained between the drive member interface portion <NUM> and the drive mechanism interface member <NUM>. In the position shown in <FIG>, the coupler input portion <NUM> is operatively connected to the coupler output portion <NUM>. That is to say, the liquid handling unit <NUM> has been connected to the drive unit <NUM> operatively and preferably mechanically. In the second position, the drive member <NUM> has been displaced relative to the sealing member <NUM>, such that the spring <NUM> is compressed and maintains the coupler output member <NUM> and the coupler input member <NUM> in engagement.

The sealing member <NUM> is axially and preferably rotationally secured relative to the drive unit housing <NUM>. The sealing member <NUM> may have a fixing portion <NUM>. In the fixing portion <NUM>, the sealing member <NUM> may be secured to the drive unit housing <NUM>. The sealing member <NUM> may have a guiding portion or sealing portion <NUM>. The portion <NUM> may extend sleeve-like along the drive member <NUM>. At least in the sealing portion <NUM> the sealing member <NUM> is, preferably elastically, deformable. At least the sealing portion <NUM> or the entire sealing member <NUM> may be made of rubber. The fixing portion <NUM> may be less easily deformable than the sealing portion, e.g. more rigid or stiff. The fixing portion <NUM> may be structurally reinforced, e.g. to provide appropriate rigidity, and/or be resilient, e.g. it may comprise a spring member, for example of metal. A radially resilient fixing portion may assist in securing the sealing member <NUM> to the drive unit housing <NUM>, e.g. by clamping the sealing member to the drive unit housing such as by exerting a radial outward force which is reacted by an inner wall of the housing. The sealing portion <NUM> may be radially inwardly offset from the fixing portion <NUM>. The sealing portion <NUM> and the fixing portion <NUM> may be axially aligned. A radially outwardly facing surface of the sealing portion <NUM> may be arranged radially offset from a radially inwardly facing surface of the fixing portion <NUM>. The radially outwardly facing surface of the sealing portion <NUM> may axially overlap with and/or face the radially inwardly facing surface of the fixing portion <NUM>. The sealing member <NUM> comprises a sealing surface or sealing lip. The sealing surface or lip <NUM> may be arranged in the interior of the sealing portion. The sealing surface or lip <NUM> may protrude radially inwardly into a hollow defined by the sealing portion <NUM>. The sealing surface or lip <NUM> may have a pointed and/or radially inwardly protruding end. The sealing surface or lip <NUM> may extend circumferentially around the drive member <NUM>. The sealing portion <NUM> may have muffle-like or sleeve-like shape. A radial free end of the surface or lip <NUM> may sealingly engage the drive member <NUM>.

The sealing portion <NUM> may be radially reinforced. For this purpose, a reinforcing member <NUM>, e.g. a rigid ring, may extend around an outer surface of the sealing portion <NUM>, in particular in the same axial region where the sealing surface or lip <NUM> is arranged. The reinforcement member may stabilize the sealing portion <NUM> against extensive radial deflection. Thus, the sealing force may be increased. The sealing surface <NUM>, however, is preferably still radially deformable.

By way of the sealing member <NUM>, it can be prevented, that dirt or moisture enters the sealed interior <NUM> of the drive unit <NUM> and, at the same time, frictional losses caused by the sealing member can be kept at a minimum.

In the following, several further embodiments of the drive unit <NUM> with sealing member <NUM> are discussed. The discussion in each case focuses on the differences to the other embodiments, e.g. the one discussed above. However, even though not explicitly described, features described before do also apply for the following embodiments unless it is apparent that they cannot apply. The embodiment depicted in <FIG> is very similar to the one depicted in <FIG>. The sealing member <NUM>, however, is different. As depicted, the sealing member <NUM> is also a radial shaft seal. The sealing member <NUM> comprises a fixing portion <NUM> and a sealing portion <NUM> as well. However, no reinforcements or spring structures are included in the sealing member <NUM>. Rather, the sealing member <NUM> may be a unitary body of elastic material, e.g. of rubber. The fixing portion may fix the sealing member to the drive unit housing <NUM> in a force-fit engagement, e.g. by way of a snap-fit, where a snap interface is formed between the drive unit housing and the sealing member. For doing so, for example a ring-like circumferential protrusion <NUM> of the sealing member may engage a correspondingly shaped ring-like recess in the drive unit housing. The protrusion <NUM> may be provided on the sealing member and the recess on the housing or vice versa. The sealing member <NUM> is axially secured to the housing. The sealing member <NUM> may comprise a circumferentially disposed region of increased radial wall thickness which increases the radial stability of the sealing member. The protrusion <NUM> may be formed by an outer surface of this region. An inwardly pointing protrusion may also be formed which is arranged to face the sealing section <NUM>. The inwardly pointing protrusion and the protrusion <NUM> together may define a ring-like structure.

The embodiment shown in <FIG>, <FIG> largely corresponds to the one shown in <FIG>. However, in this embodiment, it is ensured that in the first position, depicted in <FIG>, when the liquid handling unit is not coupled to the drive unit <NUM>, the tightness of the sealed interface between the sealing member <NUM> and the drive member <NUM> is increased as compared to <FIG>. In <FIG>, the tightness of the sealed interface is not different in the first and second positions of the drive member. Insofar, <FIG> shows an embodiment not in accordance with the invention which requires a different tightness of the sealed interface in the first position and in the second position. For increasing the tightness of the sealed interface, it is ensured that, in the first position which is depicted in <FIG>, the sealing surface <NUM> is radially outwardly displaced relative to the position of the sealing surface <NUM> in the second position depicted in <FIG>. As the sealing surface <NUM>, the sealing portion <NUM> or the entire sealing member is elastically deformable or resilient, in <FIG> the restoring force which tends to restore the undefined shape the sealing portion <NUM> is increased as compared to the <FIG> situation where the liquid handling unit <NUM> is coupled to the drive unit <NUM>.

The drive member <NUM> comprises two different sections, a first section <NUM> and a second section <NUM>. In the first position, the sealing member <NUM> engages the first section <NUM> and in the second position the sealing member engages the second section <NUM>. The sections <NUM> and <NUM> have different outer diameters. Particularly, the outer diameter of the first section <NUM> is greater than the one of the second section <NUM>. Thus, the elastic deformation in the first position is greater and results in correspondingly increased elastic restoring force, which acts radially inwardly and increases the tightness of the seal in the first position over the one in the second position, where the diameter is smaller. Between the first section <NUM> and the second section <NUM>, a sloped surface may be arranged to allow for a smooth radial displacement of the sealing surface <NUM> and the accordingly elastic deformation of the sealing portion <NUM> of the sealing member <NUM>. In the second position, the sealing force is still present but smaller than in the first position such that the movement to drive operation in the liquid handling unit is not hindered significantly while still maintaining a sealed interface. In the second position, the drive member <NUM> has been displaced relative to the sealing member <NUM> such that the second section <NUM> is brought into engagement with the sealing member <NUM>.

The embodiment depicted in <FIG> is also an embodiment, where the tightness of the sealed interface in the first position of the drive member <NUM> is increased as compared to the second position. However, the solution is different as compared to the one described previously. The drive member comprises a transfer member <NUM>. The transfer member <NUM> may be a protrusion on the drive member. The transfer member <NUM> may extend circumferentially around the drive member or not. The transfer member <NUM> may have a, e.g. circumferential, recess <NUM> which is configured to receive a section of the sealing member and/or to radially inwardly displace the sealing surface <NUM> and to maintain the sealing surface in the displaced position if the drive member <NUM> is in the first position relative to the sealing member <NUM>. The radial inward displacement may be effected by an oblique or curved surface on one of the sealing member and the transfer member which interacts with a corresponding surface of the other element when the drive member moves relative to the sealing member from the second position into the first position. As depicted, the recess <NUM> may have a sloped or curved surface <NUM>, which interacts with a corresponding surface of the sealing portion <NUM>. Due to the mechanical cooperation between the transfer member <NUM> and the sealing member <NUM>, a force can be transferred to the sealing member <NUM> via the drive member. This force may be a residual biasing force still present in the spring <NUM> in the first position. The force may be used to radially inwardly displace the sealing surface <NUM> on account of the public surface of the transfer member. The force transferred by the drive member to the sealing member is expediently an axially directed force. The axially directed force may be converted into a radial inwardly directed force by the surface <NUM>, which increases the tightness of the seal. As the transfer member stays in contact with the sealing member in the first position, a radial outward movement of the sealing surface is prevented. The remaining axially directed force, e.g. the spring force, may be reacted by the axial fixation of the sealing member to the drive unit housing <NUM>, accordingly.

Therefore, in the first position (<FIG>), the sealed interface is tighter as opposed to the second position (<FIG>), where the transfer member <NUM> is not in mechanical cooperation with the sealing member <NUM>.

In the present disclosure, the drive unit, the liquid handling unit and/or the medical device, in particular an interior of the respective entity, may be sealed against moisture, water, water jets, and/or dust. The respective seal may be effected by the sealing member <NUM> and/or one or more additional sealing members, e.g. one which seals the actuator and/or one which seals a power source replacement closure which can be opened to replace the power source. For example, the respective entity - drive unit, liquid handling unit, or medical device where the drive unit and the liquid handling unit are assembled to one another - may have a water ingress protection, e.g. as defined in EN <NUM>. For example, when the liquid handling unit is connected to the drive unit, the assembly preferably provides water ingress protection of class IPX5 and/or IPX8 according to EN <NUM>. The test conditions for class IPX8 are defined as: submerged to <NUM> for at least <NUM> and submerged to <NUM> for at least <NUM>. The reusable drive unit individually, i.e. when the liquid handling unit is not connected to the drive unit or when the drive member is in the first position, preferably provides water ingress protection of class IPX5 and/or IPX7 according to EN <NUM>.

Claim 1:
A drive unit (<NUM>) for a medical device (<NUM>), comprising:
- a drive unit housing (<NUM>),
- a drive member (<NUM>) which is retained in the drive unit housing and movable relative to the drive unit housing to drive an operation of the medical device, the drive member comprising a coupler output portion (<NUM>) which is configured to be operatively connected to a liquid handling unit (<NUM>),
- a drive mechanism (<NUM>, <NUM>, <NUM>) retained in the drive unit housing, wherein the drive mechanism is coupleable or coupled to the drive member via a mechanism interface (<NUM>) and is configured to transfer a driving force or torque to the drive member,
- a sealing member (<NUM>), the sealing member being provided to establish a sealed interface with the drive member, wherein the sealed interface defines a sealed section (<NUM>) of the interior of the drive unit housing, wherein the mechanism interface is arranged within the sealed section and the coupler output portion is arranged outside of the sealed section, wherein the drive member (<NUM>) is axially movable relative to the sealing member (<NUM>) from a first position to a second position, and wherein the drive unit is configured such that a tightness of the sealed interface is different in the first position and in the second position.