WO2015162185A1 - Indicateur de temporisation magnétique, et dispositif d'injection comprenant un tel indicateur - Google Patents

Indicateur de temporisation magnétique, et dispositif d'injection comprenant un tel indicateur Download PDF

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Publication number
WO2015162185A1
WO2015162185A1 PCT/EP2015/058730 EP2015058730W WO2015162185A1 WO 2015162185 A1 WO2015162185 A1 WO 2015162185A1 EP 2015058730 W EP2015058730 W EP 2015058730W WO 2015162185 A1 WO2015162185 A1 WO 2015162185A1
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WO
WIPO (PCT)
Prior art keywords
magnetic
reservoir
time delay
magnetic field
delay indicator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2015/058730
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English (en)
Inventor
André LARSEN
Jan Harald Preuthun
Peter Kjul
Svend Egenfeldt
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Novo Nordisk AS
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Novo Nordisk AS
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Publication of WO2015162185A1 publication Critical patent/WO2015162185A1/fr
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Ceased legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
    • A61M5/178—Syringes
    • A61M5/24—Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic
    • G—PHYSICS
    • G04—HOROLOGY
    • G04F—TIME-INTERVAL MEASURING
    • G04F13/00—Apparatus for measuring unknown time intervals by means not provided for in groups G04F5/00 - G04F10/00
    • G04F13/06—Apparatus for measuring unknown time intervals by means not provided for in groups G04F5/00 - G04F10/00 using fluidic means
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M5/00—Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
    • A61M5/178—Syringes
    • A61M5/31—Details
    • A61M2005/3125—Details specific display means, e.g. to indicate dose setting
    • A61M2005/3126—Specific display means related to dosing
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/02—General characteristics of the apparatus characterised by a particular materials
    • A61M2205/0272—Electro-active or magneto-active materials
    • A61M2205/0288—Electro-rheological or magneto-rheological materials
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2205/00—General characteristics of the apparatus
    • A61M2205/58—Means for facilitating use, e.g. by people with impaired vision
    • A61M2205/583—Means for facilitating use, e.g. by people with impaired vision by visual feedback

Definitions

  • the present invention relates to magnetic time delay indicators and to medical injection devices for administering a drug into the body of a subject user wherein the medical injection devices incorporate such magnetic time delay indicators.
  • Some medication such as insulin
  • a medical delivery device such as an injection pen.
  • the typical diabetes patient will require injections of insulin several times during the course of a week or a day.
  • typical injection devices such as the one disclosed in WO 2006/076921 , do not address the problem of a user not remembering when the last injection was administered.
  • Some prior art devices such as the electronic syringe disclosed in WO 97/30742, are provided with an electronic monitoring system adapted to automatically start an electronic timer when a selected dose is injected and to show the progress in time on an electronic display.
  • Such injection devices generally provide an acceptable solution to the problem addressed above.
  • the solution with integrated electronics will in most cases not be economically viable.
  • such a solution may not be environmentally acceptable due to the potential increase in the disposal of electronic components such as batteries etc.
  • WO 2010/127995 and WO 2010/023303 include disclosure of medical injection devices that incorporate lapsed time indicators of a type that makes them suitable to be used as pre-filled devices.
  • the particular embodiment shown in fig. 2 of WO 2010/023303 relates to a type of lapsed time indicator that makes use of a mechanical time delay device.
  • a spring is tensed as part of the initial injection procedure. The spring is utilized to operate the mechanical time delay device during lapse of the pre-defined time interval. In such a design it is a challenge to ensure optimal operation both during injection and during lapse of the pre-defined time interval to provide time indication signals that fully reflects the history of use of the device.
  • WO 201 1/123515 discloses a reversible timer system that includes a liquid disposed within a cavity defined by first and second substrates where the fluid spreads from an equilibrium state to an active state upon application of a force to the system and wherein the liquid contracts upon relief of said force. Further related timer devices are disclosed in WO 201 1/050128. Still further, WO 2013/072412 discloses magnetic time delay indicators wherein a magnetic liquid is physically moved by a magnet.
  • Some applications require a reversal time for the time delay indicator to lie in the order of several minutes or even in the order of hours.
  • activation of the time delay indicator activates a liquid that slowly reverses back into an initial configuration
  • it is a challenge to ensure that a desired reversal time is accurately and consistently obtained even when subjected to a variety of different ambient conditions.
  • timer device solution suitable for use in medical injection devices, that is improved having regard to timing precision and that works consistently at various ambient conditions.
  • the present invention relates to a magnetic time delay indicator comprising:
  • first reservoir and a second reservoir interconnected by a fluid communicator
  • a magnetic liquid arranged to be at least partly accommodated within the second reservoir and configured to flow towards the first reservoir through the fluid communicator
  • pressure generating means configured for generating a driving pressure on the magnetic liquid for urging the magnetic liquid to flow from the second reservoir towards the first reservoir, and an activator being activatable to enable flow of magnetic liquid from the second reservoir to the first reservoir, wherein the duration for an amount of magnetic liquid to flow from the second reservoir to the first reservoir provides an indication of elapsed time since activation of the activator,
  • the magnetic time delay indicator defines a magnetic field generator arrangement configured for applying a magnetic field on the magnetic fluid, the magnetic field generator arrangement comprising a first magnetic field generator arranged at the fluid communicator to predominantly apply a magnetic field on magnetic liquid present in the fluid communicator to control the viscosity of the magnetic liquid present in the fluid communicator.
  • the presence of the first magnetic field generator to apply a magnetic field on the magnetic liquid at or in the fluid communicator enables increased control of the flow through the communicator.
  • the magnetic liquid may be selected as a ferrofluid and/or a magnetorheological fluid.
  • the magnetic liquid may comprise a ferrofluid and/or a magnetorheological fluid.
  • the magnetic field generator arrangement of the magnetic time delay indicator may provide a magnetic force on the magnetic liquid to cause at least a portion of the magnetic liquid present in the second reservoir to flow through the fluid communicator towards the first reservoir.
  • the magnetic field generator arrangement may comprise at least one magnet, such as a permanent magnet.
  • the magnetic field generator arrangement may in some embodiments incorporate a single magnet. In other embodiments, the magnetic field generator arrangement defines two, three or more magnets.
  • the magnetic field generator arrangement defines a self- compensating temperature compensated field strength regulator configured to regulate the flow from the second reservoir towards the first reservoir.
  • the self-compensating temperature compensated field strength regulator comprises a mounting device for the magnetic field generator arrangement so that at least a part of the magnetic field generator arrangement is movable relative to the first reservoir and/or the second reservoir to regulate magnetic field strength applied on the magnetic liquid. Said movability of the magnetic field generator arrangement may be caused by thermal expansion and/or contraction of said mounting device or by thermal expansion and/or contraction of the magnetic field generator arrangement itself.
  • the self-compensating temperature compensated field strength regulator comprises an electrically controlled magnetic field strength regulator that is controlled by signals that correlates with detected values provided by a temperature sensing element.
  • the magnetic field generator arrangement may comprise a second magnetic field generator arranged at the second reservoir configured to predominantly apply a magnetic field on magnetic liquid present in the second reservoir.
  • the second magnetic field generator is mounted movable relative to the second reservoir by means of a mounting device, where the temperature coefficient of expansion of said mounting device is selected so that it compensates for temperature induced variations in the flow of the magnetic liquid through the fluid communicator during the timing operation.
  • the first magnetic field generator arranged at the fluid communicator may provide a braking force on the magnetic liquid flowing through the fluid communicator to restrict the flow through the fluid communicator.
  • the first magnetic field generator is movably positioned relative to the fluid communicator to regulate magnetic field strength in the fluid communicator to regulate the viscosity of the magnetic liquid present in the fluid communicator. Said movability of the first magnetic field generator may be caused by thermal expansion and/or contraction of a mounting device of the first magnetic field generator or by thermal expansion and/or contraction of the first magnetic field generator itself.
  • the magnetic field generator arrangement may comprise a third magnetic field generator positionable at the first reservoir to apply a magnetic field on the magnetic liquid for urging the magnetic liquid to flow towards the first reservoir.
  • the third magnetic field generator When the third magnetic field generator is positioned at the first reservoir it may be configured to predominantly apply a magnetic field on magnetic liquid present in the first reservoir.
  • the third magnetic field generator may be arranged movable from a first position at the second reservoir to a second position at the first reservoir, and wherein the third magnetic field generator when positioned in the second position generates a magnetic pressure for causing the magnetic liquid present in the second reservoir to flow towards the first reservoir.
  • the magnetic time delay indicator may be configured for being reset by allowing fluid present in the first reservoir to flow towards the second reservoir.
  • the third magnetic field generator when the third magnetic field generator is positioned in the first position magnetic liquid present in the first reservoir is caused to flow towards the second reservoir for resetting the time delay indicator.
  • the third magnetic field generator is mounted movable relative to the first reservoir by means of a mounting device, where the temperature coefficient of expansion of said mounting device is selected so that it compensates for temperature induced variations in the flow of the magnetic liquid through the fluid communicator during the timing operation.
  • the magnetic time delay indicator may include a visual indicator enabling a user of the device to visually observe the status of the magnetic time delay indicator.
  • the magnetic time delay indicator includes at least a portion of one or more of the first reservoir, the second reservoir and the fluid communicator that is made from a material that is optically transparent allowing a user of the device to visually inspect the magnetic liquid and hence visually observe the status of the magnetic time delay indicator.
  • the magnetic properties of the liquid present in any of the first reservoir, the second reservoir and the fluid communicator may be configured to magnetically couple and operate a visual indicator that is operated by the magnetic field strength induced by the magnetic liquid. Still alternatively, other means for providing an indication of the status of the magnetic time delay indicator may be incorporated.
  • the magnetic time delay indicator includes a bypass section coupling the first reservoir with the second reservoir for allowing fluid present in the first reservoir to quickly escape to the second reservoir enabling resetting of the magnetic time delay device to be quickly performed.
  • Such bypass section may include a valve, such as a one-way valve, for allowing flow through the bypass section during resetting but preventing flow through the bypass section when the timer runs.
  • the activator may be configured so that prior to activation, the activator prevents flow of magnetic liquid from the second reservoir to the first reservoir.
  • the magnetic time delay indicator may be so configured that, after activation of the activator, i.e. when the timer runs, the duration of time for a predefined amount of magnetic liquid to flow through the fluid communicator indicates the lapse of a pre-defined time interval since activation of the activator.
  • the pre-defined time interval is longer than15 minutes, such as longer than 30 minutes, such as longer than 1 hour, such as longer than 2 hours, such as longer than 3 hours, such as longer than 5 hours, such as longer than 12 hours, such as longer than 24 hours, such as longer than 36 hours.
  • the time delay indicator comprises a magnetic liquid that is reversibly flowable between a first configuration and a second configuration wherein the first configuration defines a first visual indication and the second configuration defines a second visual indication of the time delay indicator.
  • the first and second visual indications provide an indication of the status of the time delay indicator.
  • the time delay indicator may be configured so as to re-initialize the timing function if a renewed activation of the activator occurs during lapse of a previously initiated pre-defined time interval.
  • the activator may in some embodiments be configured for operating the resetting of the magnetic time delay indicator.
  • the activator may define an activation button which is manually activatable by a user.
  • the activation button may operate the resetting as well as the activation that enables flow of magnetic liquid from the second reservoir to the first reservoir.
  • the activation button may be so configured that upon the activation button being moved from a first position to a second position, the activation button initially causes a resetting of the timer and subsequently activates the time delay indicator for allowing it to run throughout the pre-defined time-interval.
  • the activation button may be so configured that upon the activation button being moved from a first position towards a second position, the time delay indicator is reset. When the activation button is moved further towards a third position, or alternatively reversed into the first position, the movement of the activation button causes activation of the time delay indicator allowing it to run throughout the pre-defined time interval.
  • the fluid communicator defines a channel that connects the first reservoir and the second reservoir.
  • the channel may be designed to extend between the first and second reservoir along a linear path or along a curved path.
  • the fluid communicator defines a single channel or alternatively multiple channels.
  • the fluid communicator defines an orifice between the first reservoir and the second reservoir.
  • the orifice may be arranged at the interface between the first reservoir and the second reservoir, such as at a separating wall that separates the first and the second reservoir.
  • the present invention relates to a magnetic time delay indicator comprising: - a first reservoir and a second reservoir, the first reservoir and the second reservoir being interconnected by a fluid communicator,
  • a magnetic field generator arrangement providing a magnetic force on the magnetic liquid to cause at least a portion of the magnetic liquid present in the second reservoir to flow through the fluid communicator towards the first reservoir, the flow of the magnetic liquid through the fluid communicator towards the first reservoir providing an indication of elapsed time
  • the magnetic field generator comprises a self-compensating temperature compensated field strength regulator configured to regulate the flow from the second reservoir towards the first reservoir.
  • the self-compensating temperature compensated field strength regulator may be so configured that at least a part of the magnetic field generator arrangement is configured to be moved relative to the first reservoir and/or second reservoir in response to variations in temperature to regulate magnetic field strength applied on the magnetic liquid.
  • the magnetic field generator arrangement may comprise a first magnetic field generator disposed at the fluid communicator to predominantly apply a magnetic field on magnetic liquid present in the fluid communicator.
  • the first magnetic field generator may be configured to be moved relative to the fluid communicator in response to variations in temperature to regulate magnetic field strength applied on the magnetic liquid present in the fluid communicator.
  • the time delay indicator according to the second aspect may include any of the features described in accordance with the first aspect.
  • the present invention relates to a medical delivery device, such as a medical injection device, having a time delay indicator either attached to or integrated within the device.
  • the time delay indicator of the medical delivery device may include any of the features described in accordance with the first and/or the second aspect.
  • the time delay indicator of such device incorporates an activator configured for being activated to enable flow of magnetic liquid from the second reservoir to the first reservoir.
  • the activator may in some embodiments further define an expelling activator to control expelling a dose of drug from the medical delivery device.
  • the activator may be adapted for manual activation by a subject user to cause expelling of a dose of drug.
  • the time delay indicator is automatically activated for causing the time delay indicator to operate for a predefined duration of time.
  • the time delay indicator when the user of the injection device operates the injection device for insertion of a needle of the device into a target site, the time delay indicator is automatically activated for causing the time delay indicator to operate for a predefined duration of time.
  • Such device may include a needle shielding portion and a held injection needle and wherein these components move relative to each other as the injection needle is inserted into the target site.
  • the time delay indicator may be configured to be automatically activated when the needle shielding portion and the needle move relative to each other.
  • the medical delivery device may for example be in the form of an injection pen, either of the durable type where a medicine filled reservoir or cartridge is removably attached or of the pre-filled type where a medicine filled reservoir or cartridge is irremovably arranged in the pen.
  • the medical delivery device may be in the form of a doser.
  • the medical delivery device may be of the manual type, where a user, during injection, supplies the force necessary for expelling medicine from the reservoir.
  • Such device may include an injection button that is so configured that the injection button is forced to continuously move from a pre-injection position into a post-injection condition as a dose expelling operation progresses.
  • the medical delivery device may be of the kind commonly known as a wind-up pen or AutoPen®, where energy accumulated in a spring device is released by pressing on an injection button to automatically expel a dose of the medicine.
  • a wind-up pen or AutoPen® where energy accumulated in a spring device is released by pressing on an injection button to automatically expel a dose of the medicine.
  • Such device may be configured e.g. as an injection device where the user, during an initial procedure such as dose setting, supplies the mechanical energy required for the expelling operation, the mechanical energy being stored as potential energy for example in a spring member.
  • the injection device may be of a kind where the mechanical energy required for expelling the total usable content of a container is stored in the device during manufacture thereof.
  • an injection button may be configured so as to move from a rest position to an activated or pushed in position, where the activated position is maintained as a dose expelling operation progresses.
  • the term "medical injection device” shall be understood as any device capable of actively bringing a medicament-containing drug into the body of a user by means of an appropriate delivery mechanism such as by using a cannula or by a needle-less jet-stream.
  • a non-exhaustive list of medical injection devices within the context of the present invention comprises pre-filled or durable injectors such as pen-shaped injectors or dosers.
  • the drug may be flowable or solid such as drugs forming medicine pegs for insertion through the derma.
  • Representative medicaments includes pharmaceuticals such as peptides, proteins (e.g. insulin, insulin analogues and C-peptide), and hormones, biologically derived or active agents, hormonal and gene based agents, nutritional formulas and other substances in both solid (dispensed) or liquid form.
  • pharmaceuticals such as peptides, proteins (e.g. insulin, insulin analogues and C-peptide), and hormones, biologically derived or active agents, hormonal and gene based agents, nutritional formulas and other substances in both solid (dispensed) or liquid form.
  • Fig. 1 shows a schematic representation of a first embodiment of a time delay indicator during resetting of the timer
  • Fig. 2 shows the time delay indicator of fig. 1 during operation of the timer
  • Fig. 3 shows the basic principle of a flow reducing magnetic brake during operation of the timer
  • Fig. 4 shows the same system but where not brake magnet is applied
  • Fig. 5 is a graph showing pressure loss and magnetic drive pressure along the connecting channel for the system of fig. 4,
  • Fig. 6 shows an example of a timer system with a brake magnet applied
  • Fig. 7 is a graph showing pressure loss and magnetic drive pressure along the connecting channel for the system of fig. 6,
  • Fig. 8 is a graph illustrating the excess pressure being build up between positions 1 and 2 and insufficient pressure being available to overcome flow resistance between 2 and
  • Fig. 9 is a schematic illustration of frictional shear forces between particles and carrier fluid in section 1 and section 2
  • Fig. 10 is a schematic representation of a second embodiment of a timer system having temperature compensation
  • Fig. 1 1 is a schematic representation of a third embodiment of a timer system having temperature compensation
  • Fig. 12 shows a schematic representation of a prior art medical injection device
  • Fig. 13 shows a schematic representation of an injection pen including a time delay indicator in accordance with one aspect of the present invention
  • Figs. 14a and 14b show detailed views of selected components of the time delay indicator of the embodiment shown in fig. 13, and
  • Fig. 15 shows the activating sequence of the embodiment of the injection device shown in fig. 13.
  • the working principle of the time delay indicators is based on the behaviour and properties of magnetic liquids such as ferrofluids, which are fluids with small paramagnetic particles in it.
  • the shown embodiments utilises several features of the unique properties of ferrofluids.
  • the purpose of the cited illustrations is to illustrate the principles and not a preferred embodiment.
  • the working principle is based on a flow of a fluid between two reservoirs through a narrow channel connecting the two reservoirs. When a certain amount of fluid in one reservoir moves from this reservoir to the other due to a pressure difference the flow velocity is determined by the pressure difference between the reservoirs and the pressure drop of the flow between the reservoirs.
  • the pressure drop depends upon the cross sectional area of the connecting channel and the viscosity of the fluid. Both the viscosity of the fluid and the cross section area of a pipe or channel are depending on the temperature. In normal, simple situations, the viscosity drops and the cross sectional area of a pipe increases with rising temperature, both of which causes the flow velocity to increase and thus the time to move a certain volume from one reservoir to another through a channel will decrease with rising temperature.
  • ferrofluid as the fluid in the channel between the two reservoirs
  • the viscosity of a ferrofluid can be adjusted and varied by application of a magnetic field.
  • the properties of ferrofluids enable the use of magnets to provide driving pressure for the system as well as generating a variable viscosity.
  • the pressure necessary to drive the flow between the two reservoirs are created by use of magnetic pressure in ferrofluids. Magnetic pressure occurs when a ferrofluid is subjected to a magnetic field. The magnetic forces pull the particles within the fluid towards the magnet and along with the particles, the fluid.
  • the pressure created is thus a negative pressure in the sense that it "pulls” rather than “push” as a conventionally pressurized fluid would.
  • a magnetic driving pressure difference between two interconnected reservoirs will create a flow towards the higher pressure instead of towards the lower pressure, as a normal fluid would.
  • the time delay indicator 100 includes a first reservoir 101 and a second reservoir 102 that are interconnected by a channel 103 through which a quantity of a ferrofluid 170 is adapted to flow.
  • the time delay indicator further includes magnetic field generators in the form of a plurality of magnets.
  • a first magnet M-i is positioned near the second reservoir.
  • a second magnet M 2 is positioned near the channel whereas a third magnet M 3 is positioned near the first reservoir.
  • either the first and/or the second reservoir may be used as a display providing visual feedback to the user of the status of the time delay indicator, in particular when the timer runs and when the timeout has occurred.
  • fig. 1 which shows the time delay indicator 100 during reset/activation of the system
  • the magnet M 3 is moved from the position under the first reservoir to a position under the second reservoir, thereby significantly increasing the magnetic pressure in the second reservoir to allow quick reset of timer, through the connecting channel and into the second reservoir.
  • both of the two stronger magnets M-i and M 3 contribute to creating the driving pressure for resetting the system and the fluid flow is only countered by the flow resistance and the much weaker magnet M 2 .
  • the magnet M 3 may be moved back to its position under the first reservoir. This condition, as shown in fig. 2, activates the time delay indicator enabling the time delay indicator to run.
  • Magnet M 3 is slightly stronger than magnet M-i , which is significantly stronger than the magnet M 2 .
  • the magnet M 2 does not contribute to the hydraulic pressure as such. It does however introduce a "mismatch" between hydraulic pressure and magnetic pressure along the interconnecting channel. This will be explained more thoroughly below.
  • Fig. 3 schematically illustrates the basic principle of a flow reducing magnetic brake that acts during timer operation of the time delay indicator.
  • Fig.4 illustrates a time delay system with no brake magnet applied. Note that the magnetic pressure should be regarded as negative pressures and flow does consequently go from low to higher magnetic pressure.
  • a magnet M 3 is placed under the first reservoir, creating a magnetic pressure P 3 of 100% (Reference value).
  • a second magnet Mi is placed under second reservoir, creating a magnetic pressure of 30% of P 3 . Since no brake magnet is applied, the pressure drop must be linearly distributed along the connecting channel having the length /.
  • Fig. 5 is an illustration of pressure loss and magnetic drive pressure along the connecting channel.
  • the drive pressure and pressure loss are coinciding, which means that the drive pressure just balances out the flow resistance and thus the flow rate is constant.
  • the resulting magnetic pressure along / is shown in fig. 7, illustrating the pressure loss and magnetic drive pressure along the connecting channel.
  • the fluid is a ferrofluid and we in a sense have two fluids and two driving pressures and two hydraulic losses.
  • Fig. 9 The left-hand side of Fig. 9 is an illustration of frictional shear forces between particles and carrier fluid in section 1 (between the second reservoir and the position of M 2 ).
  • the right- hand side of fig. 9 is an illustration of frictional shear forces between particles and carrier fluid in section 2 (between the position of M 2 and the first reservoir).
  • first section position 1 to 2
  • the carrier fluid and the particles move in the same direction (see fig. 9, left-hand side).
  • the particles will be driven by magnetic forces aiding the flow and overcoming flow friction forces by "dragging" the carrier fluid with them (maybe aided by an applied hydraulic pressure).
  • the carrier fluid is being "dragged” and to some extent slows down the flow of magnetic particles due to frictional shear forces between the particles and the carrier fluid.
  • the hydraulic pressure or driving magnetic pressure
  • the magnetic particles are (partially) being driven by the magnetic field and shear forces between particles and carrier fluid are relatively low. This may be best understood if thought of as three individual flows.
  • First flow is part of the particles being driven by the magnetic driving force created by the magnetic pressure difference ⁇ 13 .
  • Secondary flow is the carrier fluid flow driven by either an external hydraulic pressure or entirely from the part of magnetic particles of “first flow”. If driven entirely by magnetic pressure, frictional shear forces between these particles are higher than if an external hydraulic pressure induced some or all of the driving pressure, but regardless of the flow is driven entirely by magnetic force, entirely by external hydraulic pressure or a combination of both, circumstances of these two flows will be identical in both sections (on both sides of M 2 ).
  • the "third flow” is the remaining part of the particles that are driven by M 2 . Since the force from M 2 on these particles in section 1 is in the same direction as the flow of the other part of the particles and the carrier fluid, these particles are being pulled by the other two flows to some extent. Therefore frictional shear forces between "third flow” and the two other flows are limited to the shear forces arising from differences in size of force being applied on them by hydraulic and magnetic forces.
  • section 2 the two first flows are given the same conditions as in section 1. Both the hydraulic flow and the part of the particles are subjected to the magnetic pressure difference ⁇ - ⁇ 3 as in section 1.
  • the third flow being the part of particles subjected to the magnetic force from magnet M 2 is now being applied a magnetic force opposite the flow direction and frictional shear forces now not only have to transmit differences in size of force, but also in direction of force.
  • the frictional shear force exerted by the "third flow” in section 2 is three times higher than the frictional shear forces exerted in section 1.
  • the increase in frictional shear forces is by definition an increase of the viscosity of the fluid.
  • An increase in viscosity at a given pressure difference results in an increase of flow resistance and hence in a reduction of flow velocity.
  • ferrofluids behave like other fluids and flows can be calculated from well-known formulas.
  • the ferrofluid behaves very different than other fluids on especially two points.
  • a magnetic pressure is introduced in the fluid and second, the viscosity of the fluid increase.
  • the magnitude of viscosity change depends very much on the size of the paramagnetic particles in the fluid as well as of course the strength of the applied magnetic field and the direction of the applied field relative to the flow direction.
  • the magnetic pressure introduced in a ferrofluid when applying a magnetic field to it is given by:
  • viscosity When using a magnetorheological fluid, viscosity can be increased until almost being a solid by applying a magnetic field. In this case, where the viscosity is multiplied by a factor 100 or so by application of a magnetic field, the viscosity of the carrier fluid and its temperature dependence is negligible and will have no practical influence.
  • Such fluids are based on particles in micrometer scale and due to their significantly larger particle size (compared to those of ferrofluid in nanometer scale), they are too dense for Brownian motion to keep them suspended and they are thus subject to sediment of particles and thickening over time. This can to some extend be reduced by use of proper surfactants and higher density of carrier liquid.
  • ferrofluids have a much more limited potential of increasing viscosity by application of a magnetic field and will to some extend be influenced by variations in viscosity of the carrier fluid caused by temperature variations.
  • the application of such fluids may require the use of means to compensate for temperature induced variations of viscosity.
  • the first principle makes use of a flow restrictor wherein the hydraulic diameter is reduced to counter the effects of decrease in viscosity of the ferrofluid due to an increase of temperature decreasing the viscosity of the carrier fluid of the ferrofluid.
  • the second principle makes use of the characteristics of a magnets field strength decreasing with the square of the distance from the magnet.
  • This principle relies on the magnet being mounted by a mounting device comprising a structure made of a material with a relatively high thermal expansion coefficient that causes the distance from the magnet to the ferrofluid to vary with temperature and thus the applied field strength to vary with the temperature.
  • the variations in magnetic field strength are obtained by utilising the dependency between magnetic field strength and distance from magnet, where the field strength decreases by the square of the distance.
  • FIG. 10 shows a second embodiment of a time delay indicator where the driving magnetic pressure (P 3 ) can be reduced by increasing magnet distance from the ferrofluid with increasing temperature to compensate for reduced viscosity and/or the retaining magnetic pressure (P-i) can be increased by reducing magnet distance from the ferrofluid. Both of these options reduce the magnetic drive pressure difference to compensate for reductions in viscosity caused by an increase in temperature.
  • each of the magnets M-i and M 3 are mounted on respective mounting devices 190. In other embodiments only one of the magnets M-i and M 3 may be mounted on a mounting device configured for varying the applied field strength.
  • Shown in fig. 1 1 is a third embodiment of a time delay indicator.
  • the distance between the brake magnet M 2 and the connecting channel can be decreased with increasing temperature to magnetically induce an increase in viscosity to compensate for a temperature induced decrease in viscosity of the carrier fluid.
  • the brake magnet M 2 is disposed on a mounting device 190 which is configured to move the brake magnet M 2 by utilizing thermal expansion and thermal contraction of parts of the mounting device 190.
  • the mounting device 190 may be adapted to decrease the distance of brake magnet M 2 relative to the connecting channel 103 upon increasing temperature. This causes the magnetic field strength applied by brake magnet M 2 on the magnetic liquid 170 present in the connecting channel to increase which counteracts a decrease in viscosity which is due to the rising temperature.
  • time delay indicators may for example be incorporated in devices wherein the occurrence of a particular activity needs to be indicated for a predetermined duration.
  • One non-limiting example could be a medical delivery device, such as an injection pen for administration of a single or a multitude of doses of a medicament where the activity that require monitoring may be the occurrence of an expelling action and where the time delay indicator indicates for a predefined time interval the occurrence of a performed expelling action.
  • Fig. 12 depicts a schematic representation of a prior art medical injection system forming an injection pen 1 comprising a medicament filled cartridge 2 which is accommodated in a distal part of the injection pen.
  • the injection pen 1 includes a housing that defines a central longitudinal axis.
  • the proximal part 4 of the device holds a mechanism 7 for setting and injecting specific doses of a medicament from the cartridge 2.
  • the cartridge 2 comprises a passage in a distal neck part which is sealed by a pierceable sealing member 5.
  • Cartridge 2 further comprises a slideably mounted piston 6 which is adapted to slide towards the distal part of the container 2 when a distally directed force is exerted on the piston 6.
  • medication is delivered through an injection needle 3 which may be releasably secured to the distal part of the injection pen.
  • the injection pen further comprises a dose dial 9 which may be manipulated by the hand of a user for selecting a dosage, the size of the selected dosage being visible in window 10.
  • the injection pen 1 further comprises an expelling activator in the form of an injection button 8 for injecting a selected dosage.
  • a distally directed force on the button 8 exerted by the hand of the user, activates the mechanism 7 of the pen for causing a dosing movement of the piston 6 of cartridge 2.
  • Fig. 1 further shows a cap 1 1 which is adapted to be removably attached to the distal part of the injection pen. In the storage state, when the cap 1 1 is attached to the injection pen 1 , the cap protects the cartridge 2 and the needle 3.
  • Fig.13 is a schematic representation of an injection pen 1 ', structurally similar to the injection pen shown in fig. 12, but having a time delay indicator 100' arranged at the proximal end of the device 1 '.
  • the time delay indicator 100' is a liquid based time delay indicator incorporating a magnetic liquid that is controlled by one or more magnetic field generators in accordance with the principles discussed above.
  • the one or more magnetic field generators may be provided as one or more separate magnets.
  • the time delay indicator 100' may further include temperature compensating means that controls the magnetic field strength from one or more of the magnetic field generators to compensate for variations in viscosity of the magnetic liquid caused by variations in operating temperature.
  • the time delay indicator 100' is intended to be an integral part of an injection device 1 ', such as being formed as a member that is non-separable from the remainder of the device.
  • the time delay indicator forms part of an injection button assembly in an auto-injector having a spring actuated dose delivery mechanism.
  • suitable injection device dose delivery mechanisms are disclosed in WO 2006/076921.
  • Fig. 14a shows the time delay indicator 100' in a top view and in cross sectional views along lines A-A and B-B. In fig. 14a the time delay indicator is in a resting state wherein the time delay indicator has not yet been activated.
  • the time delay indicator 100' is composed around a timer structure 114' that is adapted to hold a quantity of a magnetic liquid 170' such as a ferrofluid.
  • the timer structure 114' is part of a time delay body 110' that further comprises components 111', 112' and 113'. In the shown embodiment the components 111', 112', 113' and 114' are components fixedly arranged relative to each other.
  • the timer structure 114' includes a tower portion that extends proximally along the central longitudinal axis from a distal part of timer structure 114'.
  • Components 111', 112' and 113' are configured to define a compartment that accommodates the tower portion of timer structure 114' within the bordering walls defined by components 111', 112' and 113'.
  • the components 111', 112', 113' and 114' define a first reservoir 101' arranged proximally to the tower portion at a central top position on timer structure 114'.
  • the components 111', 112', 113' and 114' further define a second reservoir 102' arranged at a peripheral bottom portion of timer structure 114'.
  • Component 113' forms a dome shape that is arranged on top of the timer structure 114'.
  • Component 113' is made from a transparent material that enables visual inspection of the timer structure 114' and the magnetic liquid 170' when present in the first reservoir 101'.
  • the timer structure 114' further comprises a fluid communicator in the form of a channel 103' that leads from the first reservoir 101' to the second reservoir 102'.
  • the channel 103' is formed as a narrow conduit extending along an axis from the first reservoir 101' to the second reservoir 102'.
  • the shape of the channel 103' may be formed differently, for example by forming the channel to extend along a helical path from the first reservoir 101' to the second reservoir 102'.
  • the colour of the magnetic liquid 170' and the top surface of the central top position on timer structure 114' may be selected so that the liquid is visually distinguishable from the timer structure 114' in a way so that a user of the device may readily inspect whether or not magnetic liquid 170' is present in the first reservoir 101'.
  • the time delay body 110' (111', 112', 113' and 114') is arranged movable relative to a time delay base 130'. Said relative movability ensures that the assembly 110' and 130' are able to act as an activator for operating the time delay indicator 100' for resetting the timer and allowing the timer to run.
  • the time delay base 130' is disposed on a component of the injection pen 1' which forms part of the injection button assembly. The time delay body 110' is thus movable relative to the time delay base 130' along the central axis of the injection pen 1' from a first inactivated position into a second activated position.
  • a slider 140' is coupled to the time delay body 1 10' so that the slider moves axially with the time delay body and so that the slider is movable in a lateral direction between a central position and a peripheral position relative to the time delay body.
  • the slider 140' and the timer structure 1 14' include a rail system that ensures that slider 140' is moved axially together with the time delay body 1 10' when the time delay body moves relative to the time delay base 130' and that enables said lateral movement of the slider 140' relative to the timer structure 1 14'.
  • a spring 180' is arranged to act on the slider 140' to urge the slider towards the central position.
  • a magnet 150' is disposed on slider 140' and hence the position of the magnet 150' is determined by the position of the slider 140'.
  • the magnet 150' may be referred to as magnet M 3 .
  • the time delay base 130' comprises a cam 135' having a cam surface adapted to engage a corresponding cam surface of slider 140'.
  • an externally applied force is exerted in the distal direction on the time delay body 1 10', such as when a user exerts a pressing force in the distal direction for performing an injection
  • the cam surfaces causes the slider 140' to move from the central position to the peripheral position against the force provided by spring 180'.
  • the external applied force ceases, accumulated energy released from the spring 180' causes slider 140' to be moved back from the peripheral position to the central position.
  • the magnet 150' is moved back and forth between the central position and the peripheral position.
  • the time delay indicator 100' furthermore includes brake magnets 160'.
  • the brake magnets 160' may be referred to as M 2 .
  • the brake magnets 160' are formed as a series of circular concentric magnets that are disposed at a distal wall section of the time delay body 1 10' and thus in close relationship with the distal part of the second reservoir 102'. The brake magnets 160' are thus positioned along the flow path of the magnetic liquid 170' when the magnetic liquid flows in channel 103'.
  • the time delay indicator 100' is in the resting state wherein the time delay indicator has not yet been activated.
  • the magnet 150' is located at the central position. Due to the magnetic field induced by magnet 150' the magnetic liquid 170' has been caused to flow into the first reservoir 101 ' and the magnetic liquid is observable at a central location of the timer structure 1 14'.
  • the spring 180' urges the slider 140' back into the central position. Due to the change of magnetic field caused by movement of magnet 150', the magnetic liquid 170' is forced to flow towards the first reservoir 101 '. However, due to the brake magnets 160', the duration of the return flow towards the first reservoir 101 ' is relatively long. In accordance herewith the visual indication through the transparent portion of the component 1 13' only slowly changes towards the initial state (i.e. the resting state). When the magnet 150' assumes its central position, the magnetic field applied onto the magnetic liquid 170' present in the channel 103' acts to regulate the viscosity of the magnetic liquid 170' thereby slowing down the flow and thus allowing a long time-out time. However, when the magnet 150' assumes its peripheral position, the viscosity of the magnetic liquid 170' is relatively low thereby ensuring a high flow velocity and thus enabling a short reset-time.
  • Fig. 15 schematically shows the injection device 1 ' including the time delay indicator 100' and the movement of the different parts of the injection button assembly of the device during the dose delivery activation procedure.
  • the injection pen is shown in the non-activated state, i.e. in a state corresponding to the state the device assumes between drug administering operations.
  • the time delay body 1 10' is moved relative to the time delay base 130' and the time delay indicator 100' is reset.
  • time delay base 130' is fixedly associated with a component of the expelling activator of the dose delivery mechanism
  • pressing the time delay body 1 10' further in the distal direction relative to the housing of the device causes the injection button assembly to activate the dose delivery mechanism for expelling the set dose (shown in the right-hand figure).
  • the time delay indicator is simultaneously activated to run for the predefined time interval.
  • the activated state of the time delay indicator is observable through the transparent section of time delay body 1 10'.
  • the duration of the backflow towards the initial state can be in the order of minutes or hours.
  • the time delay indicator of the device provides an indication that the expelling of a dose has been performed within the predefined time limit.
  • magnetic field generators may be incorporated, for example in proximity of the first reservoir.
  • Such magnetic field generators may be included at or in the timer structure 1 14', and in particular at or in the the tower portion of the timer structure 1 14'.
  • Suitable designs may include a time delay indicator which is adapted to cooperate or be operated by one or more other components which move(s) when an injection procedure is carried out.
  • Non-limiting examples include movable components, such as a needle shield that slides relative to a needle or relative to a housing for initialising a dose administration, a cap that moves relative to a housing for gaining access to an injection needle or for covering an injection needle subsequent to an injection, a dose setting member or dose indicator that moves during dose setting, and one or more parts of the dose delivery mechanism that moves during expelling.

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  • Biomedical Technology (AREA)
  • Hematology (AREA)
  • Vascular Medicine (AREA)
  • Engineering & Computer Science (AREA)
  • Anesthesiology (AREA)
  • Physics & Mathematics (AREA)
  • Heart & Thoracic Surgery (AREA)
  • General Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
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  • Infusion, Injection, And Reservoir Apparatuses (AREA)

Abstract

L'invention concerne un indicateur de temporisation magnétique (100, 100') qui comprend : - un premier réservoir (101, 101') et un second réservoir (102, 102'), le premier réservoir (101, 101') et le second réservoir (102, 102') étant reliés entre eux par un communicateur de fluide (103, 103'), - un liquide magnétique (170, 170') conçu pour être au moins partiellement reçu à l'intérieur du second réservoir (102, 102') et configuré pour s'écouler vers le premier réservoir (101, 101') à travers le communicateur de fluide (103, 103') pour fournir une indication de temps écoulé. L'indicateur de temporisation magnétique (100, 100') définit un agencement de générateur de champ magnétique (M1, M2, M3, 150, 160) configuré pour appliquer un champ magnétique sur le fluide magnétique (170, 170') et comprenant un premier générateur de champ magnétique (M2, 150') disposé au niveau du communicateur de fluide (103, 103') pour appliquer un champ magnétique principalement sur le liquide magnétique (170, 170') présent dans le communicateur de fluide (103, 103'), pour réguler la viscosité du liquide magnétique (170, 170') présent dans le communicateur de fluide (103, 103') lorsqu'il s'écoule du second réservoir (102, 102') au premier réservoir (101, 101').
PCT/EP2015/058730 2014-04-22 2015-04-22 Indicateur de temporisation magnétique, et dispositif d'injection comprenant un tel indicateur Ceased WO2015162185A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP14165509.2 2014-04-22
EP14165509 2014-04-22

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WO2015162185A1 true WO2015162185A1 (fr) 2015-10-29

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117249809A (zh) * 2023-11-17 2023-12-19 中铁电气化局集团有限公司 一种铁路桥梁轨道标高转移指示装置及其施工方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2555513A (en) * 1948-02-16 1951-06-05 Jr Edmund O Schweitzer Magnetic time-delay mechanism
EP1836945A2 (fr) * 2006-03-20 2007-09-26 Olympus Medical Systems Corp. Mécanisme à commutation à utiliser dans des appareils médicaux, et dispositif de capture d'images à utiliser dans des endoscopes
WO2013072412A1 (fr) * 2011-11-15 2013-05-23 Novo Nordisk A/S Indicateur magnétique temporisé et dispositif d'injection le comprenant

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2555513A (en) * 1948-02-16 1951-06-05 Jr Edmund O Schweitzer Magnetic time-delay mechanism
EP1836945A2 (fr) * 2006-03-20 2007-09-26 Olympus Medical Systems Corp. Mécanisme à commutation à utiliser dans des appareils médicaux, et dispositif de capture d'images à utiliser dans des endoscopes
WO2013072412A1 (fr) * 2011-11-15 2013-05-23 Novo Nordisk A/S Indicateur magnétique temporisé et dispositif d'injection le comprenant

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117249809A (zh) * 2023-11-17 2023-12-19 中铁电气化局集团有限公司 一种铁路桥梁轨道标高转移指示装置及其施工方法
CN117249809B (zh) * 2023-11-17 2024-02-06 中铁电气化局集团有限公司 一种铁路桥梁轨道标高转移指示装置及其施工方法

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