Field of invention

The present invention relates to the field of vaccination against viruses. The invention particularly relates to large vaccination programmes, in which a large population needs to be vaccinated within a limited time or when available volumes of vaccine is limited compared to the number of individuals to be vaccinated. Specifically, the invention relation relates to methods for operating a syringe and to a dose extraction aid for use in extracting a liquid from a vial.

Background of invention

The invention particularly relates to a situation of an epidemic or a pandemic, where a large population needs to be vaccinated a soon as possible to provide herd immunity. In such situations, the sooner the critical number of individuals in the population is vaccinated; the sooner herd immunity is achieved. The sooner herd immunity is achieved, the fewer individuals in the population will become infected and the fewer casualties will be experienced. A raging epidemic or pandemic does not only carry human costs in terms of lost lives and lost quality of life, but also have a great negative impact on society and economy. The world are currently experiencing a Covid-19 pandemic, causing lockdowns and significant limitations in peoples mobility and ability to work, shop and enjoy leisure time. In such situations, where a new virus cause an epidemic or pandemic, medical companies around the globe race to develop new and effective vaccines to c help create herd immunity. However, once a vaccine is developed, it needs to be given to the majority of the population at risk, which usually means that a very high number of individual needs to be vaccinated within a limited time. This presents two major challenges. First, it requires a vaccine produced in very high volume. Especially when dealing with a new virus, this limits availability, as production capacity will never be able to meet an instant demand. Second, the costs of new vaccines are often significant and the requirement of administering the vaccine to the majority of a population to gain herd immunity, will carry tremendous costs to the healthcare system of the population, which will also limit availability especially in large populations of low income.

When administering drugs of very high cost and/or limited availability, it becomes important from both economical and treatment oriented perspectives, to utilise the drug as efficient as possible. In relation to vaccination of individuals during and epidemic or pandemic, where supplies of vaccine may be limited, more efficient use of the available supply of vaccine can help reduce the time from vaccination starts to a sufficient number of individuals have received the vaccination, for herd immunity to be achieved.

Large vaccination programs are normally carried out by injection using disposable syringes being filled from vials containing a number of guarantied doses. Since not all of the contents in a vial can be drawn out and into a syringe and all syringe and needle systems have a dead space, leaving small amounts of drug in the syringe and needle after injection, the vials needs to be overfilled to some extent. Overfilling means that if the dose required to be injected into and individual to achieve the expected effect is Xml and the vial is to contain Y guarantied doses, the vial needs to contain Y times Xml and an additional Zml to allow for unusable remains in the vial and expected loss during normal injection procedures. Thus, a vial of Pfizers Covid-19 vaccine contains 2,25ml of vaccine, which corresponds to five guarantied doses of 0,3ml. Five doses of 0,3ml means that (at least) 1 ,5ml needs to be injected and the additional 0,75ml in the vial is to allow some to be left in the vial, as not all can be extracted, and allow a small amount to be lost in the dead space of syringe and needle. However, during practical use the amount drawn into each syringe will vary a little, most likely normally distributed. If the normal distribution of the actually injected volume were centred around a mean value of the exact dose to be taken, it would mean that half of the recipients would be under-dosed and the vaccine would be ineffective and the entire vaccination program fails its purpose. Therefore, the syringe must be filled to ensure that a minimum of the prescribed dose size is expelled in the majority of instances, increasing the mean value of the normal distribution. This means that the syringe must be filled with an added volume to ensure the mean value is beyond prescribed dose size, even with loss due to handling and dead space is taken into account.

The width of a normal distribution depends on the variation, often expressed by the standard deviation as a mean variation. The larger the variations in filling are the further beyond the prescribed dose the mean filling of the syringe needs to be, in order to keep the number of under-dosed recipients sufficiently low. Thus, the guarantied number of doses is based on an assumption of how low variations in syringe filling and loss can be expected.

This means that in order to optimise the utilisation of the contents of a vial, it is not only important to minimise or eliminate the loss of dead space and handling, but also to minimise the variations in syringe filling, while ensuring at least the prescribed dose is expelled during injection.

Thus, it is the objective of the described invention to provide a method for more efficient utilisation of a given amount of drug or vaccine in a via by reduction of dead space in syringe and needle and to minimising the variation of filling of the syringe, to reduce costs a treatment and increase the number of individuals, that can be vaccinated or treated from a given supply of drug or vaccine.

Prior art

Epidemics of a new virus covering an entire country or pandemics of a virus is luckily relatively rare in the world of today. Most epidemics seen today are related to known viruses, for which vaccines exists and are produced continuously and immediate demand is limited. Thus availability is a smaller problem and cost are usually less of an issue, since the price of vaccines for known viruses produced and stockpiled are usually much lower than newly developed vaccines in immediate demand and local epidemics require much fewer individuals to receive the vaccine to stop the outbreak. In these situations, the method generally accepted worldwide as best practice has been regarded as sufficiently efficient and in situations of abundant supplies of affordable vaccine or drug, development of new methods appear to have been of little or no interest.

Generally accepted best practice of drawing medicine or vaccine out of a vial using a syringe, are well described in literature for education of nurses and caregivers in most, if not all countries. On the U.S. National Library of medicine’s website

(https://medlineplus.gov/ency/patientinstructions/000530. htm), the section describing the steps involved in best practice of drawing medicine out of a vial reads as follows:

Step 1 : Get the Vial Ready

Prepare your medicine vial:

• If this is your first time using this medicine, take the cap off the vial.

• Wipe the rubber top clean with an alcohol pad. Step 2: Filling the Syringe with Medicine

Follow these steps to fill the syringe with medicine:

• Hold the syringe in your hand like a pencil, with the needle pointed up.

• With the cap still on, pull back the plunger to the line on your syringe for your dose. This fills the syringe with air.

• Insert the needle into the rubber top. Do not touch or bend the needle.

• Push the air into the vial. This keeps a vacuum from forming. If you put in too little air, you will find it hard to draw out the medicine. If you put in too much air, the medicine may be forced out of the syringe.

• Turn the vial upside down and hold it up in the air. Keep the needle tip in the medicine.

• Pull back the plunger to the line on your syringe for your dose. For example, if you need 1 cc of medicine, pull the plunger to the line marked 1 cc on the syringe. Note that some bottles of medicine may say ml. One cc of medicine is the same amount as one ml of medicine.

Step 3: To remove air bubbles from the syringe:

• Keep the syringe tip in the medicine. • Tap the syringe with your finger to move air bubbles to the top. Then push gently on the plunger to push the air bubbles back into the vial.

• If you have a lot of bubbles, push the plunger to push all the medicine back into the vial. Draw medicine out again slowly and tap air bubbles out. Double check that you still have the right amount of medicine drawn up.

• Remove the syringe from the vial and keep the needle clean.

• If you plan to put the syringe down, put the cover back on the needle.

While this method works well when an individual needs to take his or her insulin or a nurse or a doctor needs to administer a single injection to a patient a couple of times a day, it quickly becomes a tiresome and time consuming process when you need to prepare hundreds of syringes each day for administering a vaccine to as many individuals as quickly as possible. Preparing one hundred syringes with a given dose of vaccine, requires the individual preparing the syringes to pump air into the vials one hundred times, to avoid a vacuum forming inside the vial, preventing the drug from being drawn out. If too much air is introduced, too much drug/vaccine is forced into the syringe.

The vial then has to be turned upside-down and held up in the air, which requires the individual preparing the syringe to raise the arms above the head, which when done often enough during the day, may lead to reduced blood flow in arms and hands, as well as exhausting the muscles. This is a common problem among electricians that often work with wires and lamps above their heads and is not considered a good working position for longer duration. Furthermore, the individual preparing the syringe has to keep a close eye on the tip of a very small needle inside the fluid inside the vial and make sure the tip of the needle is always covered by the contents of the vial, as well as pulling back the plunger of the syringe to the correct line indication the desired dose size.

While still having to keep the tip of the needle submerged in the contents of the vial, the individual preparing the syringe must now tap the syringe with a finger, while holding both the syringe and the vial and maintaining the needle submerged, to move air bubbles to the top of the syringe. Then, still holding both the syringe and the vial above the head, the individual preparing the syringe needs to push the plunger forward to push air bubbles back into the vial. If there is a lot of bubbles in the contents of the syringes, the plunger has to be pushed all the way forward again and the process repeated.

When the air is removed, it has to be checked again, that the right amount is drawn up in the syringe and if not, it must be corrected by movement of the plunger. Only then, can the needle be pulled out of the syringe and the individual can lower the hands from above the head and cap the prepared syringe. Both capping the prepared syringe and introducing the needle in the vial, introduce a risk of the individual preparing the syringe to accidently sting him- or her-self.

The complicated and tiresome procedure described above increase the risk of errors and reduce the accuracy of filling the syringe with the correct amount of drug, as well as requiring bad working positions, which must be considered as obvious drawbacks of the method.

Two additional and significant drawbacks of the method currently regarded as best practice, leads to a less efficient utilization of the drug and thereby to increased costs of treatment.

As described in the above, the needle must be kept submerged in the drug or vaccine during the entire filling process. This requires the vial to contain a surplus of drug being left in the vial when last dose has been drawn out of the vial. As it will normally require the needle to be inserted several millimeters in the vial, for the individual preparing the syringe to be able to see the tip of the needle, and the individual must make sure to keep the needle tip covered, even as the level of drug or vaccine in the vial drops, several millimeters of drug or vaccine needs to be left inside the vial. As the individual also needs to be able to insert the needle in the opening of the vial, the diameter of the vial needs to be significantly larger than the diameter of the needle. If the opening of the vial is 5mm in diameter and a remaining fluid height of at least 5mm is required to be able to see the tip of the needle and make sure it is still covered when the last syringe from that vial is filled, at least 0,98ml needs to be left when the vial is considered empty. Given that the required dose size of the example was 1 ml, it means that approximately a full dose is disposed of with each vial.

Vials often come with a nominal content of five doses, which in this example would mean that an additional 20% of the vaccine is disposed of without being used. In a scenario of urgently having to administer a vaccine only available in a limited amount to as many individuals as quickly as possible, it would be highly desirable to be able to utilize an additional 20% of the available vaccine.

Even though syringes with minimized dead space are used, an additional loss is introduced using the method currently being considered best practice. As the syringe to be prepared is introduced into the vial and used to introduce air in the vial, the needle on the syringe and a small volume inside the syringe itself, in front of the plunger is filled with air. As drug or vaccine is being drawn into the syringe, this air is trapped between the drug or vaccine and the plunger. Since the indications of volume on the syringe indicated the injectable volume and the volume of air is unknown, the syringe is tapped on with a finger, to cause the trapped air to form small bubbles and leave the syringe, to enable adjustment to correct filling volume. However, this leaves the syringe filled with the adjusted dose size in addition to the volume of the dead space in the syringe and needle. Hence, a volume corresponding to the combined dead space is left in each syringe after injection and disposed of. Even when using dead space minimizing syringes, this is known to often exceed a full dose when having administered the nominal five doses from a vial. Thereby a necessary additional 20% in the vial has been loosed.

Combined, this means that a vial guarantying five doses from the manufacturer, actually needs to contain sufficient vaccine or drug for at least 7 doses or 40% more injections than nominally.

In a scenario of a large population having to receive a vaccine as quickly as possible, and available volume of vaccine is a limiting factor, a method able to utilize these additional 40%, would mean that the number of necessary vaccination could be performed in only 70% of the time otherwise required and herd immunity achieved much quicker. In addition, the costs af the drug or vaccine required to achieve herd immunity would be reduced by almost a third, which would both benefit economy and increase availability.

As health care providers, private as well as public, will be asked to, and paid for the treatment of an individual and not by the number of vials used, the invention presented in this document have a clear industrial application, as most healthcare providers would seek to treat as many individuals at the lowest cost possible and in case of an epidemic or a pandemic, also as quickly as possible. Some companies already produce and sell vial adapters to ease the process of filling a syringe with drug or vaccine from a vial.

A vial adapter is a unit that clicks on to the top of a vial and penetrates the septum of the vial, introducing a valved inlet of air and a valved outlet of contents through a socket. When using a vial adapter, the individual preparing syringes for injection do not need to put at needle on the syringe to penetrate the septum of the vial in order to gain access to the drug inside. Instead, the syringe is placed in the socket, whereby the outlet valve is opened. This ease the task of the individual preparing the syringe, as the risk of accidental sting during connecting the syringe and the vial is eliminated. The individual preparing the syringe is also relieved from having to keep an eye on a needle and keeping is covered with fluid inside the vial. Use of a vial adapter also allows more drug to be drawn out of the vial, because the opening can be placed closer to the septum, requiring less fluid to remain to avoid air being sucked into the syringe.

While a vial adapter do make it less cumbersome to prepare a syringe, it still requires the vial to be turned upside down imposing an uncomfortable working position on the individual preparing the syringe. Tests imply that the reduced workload of the individual preparing a syringe when using a vial adapter and not having to maintain a needle tip below the fluid surface during the other activities involved when drawing drug into the syringe, reduce the variations in filling amount. Although a vial adapter increase filling accuracy by reducing variations in filling volume and increase the amount of drug that can be drawn from a vial, which are both factors benefitting the utilization of the drug in a vial, the vial adapter does not address the loss from the dead space of the syringe and injection needle. Thus, an even higher rate of utilization of a drug from a vial can be achieved by using the invented method disclosed in this document, than the use of a vial adapter allows.

Turning now to background for dose extraction aids:

The present invention also relates to a dose extraction aid for use in extracting a liquid from a vial, said vial having an opening, an exterior bottom surface opposite the opening, a cap with a septum covering the opening, and a central axis extending from the opening to the exterior bottom surface perpendicular to a bottom plane defined by said bottom surface, said dose extraction aid comprising: a base unit having a base surface configured for being arranged on a horizontal support surface; a vial holder configured for holding a vial and defining a vial axis, where, when a vial is arranged in the vial holder, the central axis of the vial coincides with the vial axis; and an extraction unit holder configured for holding an extraction unit comprising a cannula for extracting a liquid from the vial arranged in the vial holder and a hub for connecting the cannula to a syringe, where said extraction unit holder defines an extraction axis, and where, when the extraction unit is arranged in the extraction unit holder, at least a section of the cannula of the extraction unit closest to the hub coincides with the extraction axis. The invention further relates to a method for extracting a dose of a liquid from a vial using a syringe and a dose extraction aid.

A dose extraction aid of the type defined above is known for example from US3833030A. This dose extraction aid helps position a vial and an extraction unit with a syringe in relation to each other and limits the possible movement of the plunger of the syringe so that it is automatically stopped when a desired volume of the liquid held in the vial has been extracted. The primary purpose of this dose extraction aid is to help the visually impaired, but it may also be used by medical professionals needing to extract many identical doses, for example in connection with mass vaccination.

Another, simpler type of dose extraction aid is known from US5776124A. This dose extraction aid, however, needs to be held in the hand during extraction of the liquid from the vial, potentially resulting in harmful working positions when many doses are to be prepared. Moreover, the manual handling of the vials may result in deterioration of sensitive liquids, such as some types of vaccines.

A still further dose extraction aid is known from US4475915A. This dose extraction aid is mounted on a wall and the vial is arranged upside-down in a vial holder with the septum facing an opening therein. The cannula of the extraction unit is then inserted through the opening in the vial holder, while the syringe is held in position by a being inserted in a recess at a distance from the vial holder. By the opening and the recess being arranged in continuation of the central axis of the vial, a safe and easy insertion of the cannula into the vial is ensured.

These dose extraction aids have worked well when it comes to ensuring that the correct amount of liquid is extracted from the vial, but there is a desire to provide a further improved dose extraction aid which reduces loss of the often very valuable liquid contained in the vials, such as for example vaccines.

It is therefore an object of the invention to provide a dose extraction aid which allows a higher percentage of the liquid in a vial to be extracted in a safe manner so that the amount of liquid left in discarded vials is reduced.

Another further object of the invention is to reduce loss resulting from syringes not being emptied completely during administration to patients.

Another further object of the invention is to provide a dose extraction aid, which is well-suited for the extraction of liquids that are sensitive to motion and therefore needs to be handled with extra care.

Another further object of the invention is to provide a dose extraction aid which may contribute to reducing work in harmful working positions.

Summary of invention

Methods for operating a syringe according to the invention are set forth in the appended claims 11 to 28.. In first aspect of the invention provides a method for discharging a syringe. A second aspect of the invention provides a method for reducing inaccuracy and variations in dose size of a liquid substance when filling a syringe. A third aspect of the invention provides methods for providing a liquid substance in a syringe. The invented methods enable more efficient utilisation of a given amount of drug or vaccine in a vial, by reducing workload, time consumption and above all, reducing the amount of drug being wasted in the process of injection. This enables more individuals to receive the drug or vaccine from a given amount and thus reduces cost and increase availability.

The invented methods are based on reducing the loss due to dead space, by the introduction of an air inlet into the vial from which the drug or vaccine is taken by a syringe and introducing a small pocket of air filling the dead space of the syringe, that would otherwise normally be filled with the drug or vaccine of the vial and go to waste. To reduce the variations and increase the accuracy in dose size, the method further describes a method of calibrating the volume indications on the particular syringe used.

Providing a substance in a syringe is understood to be filling a syringe with a substance.

The fluid reservoir is suitably the ambient air, i.e. the air present when performing the method. The fluid reservoir could also be a headspace of a vial.

In the first aspect the invention provides of a method of expelling drug or vaccine from a syringe, wherein the drug or vaccine is placed in front of a volume of air being enclosed in the syringe between the plunger and the drug being drawn into the syringe. The volume of air should preferably be limited to a volume corresponding to the dead space of the syringe with the injection needle to be used fitted. The method may be used with means of aiding the individual preparing the syringe (from here on referred to as “the operator”). It is a further aspect of the invention to provide a method of more accurate filling for better accuracy of injection dose and smaller variations of said injection dose.

Several of the required steps in current best practice and the steps necessitating inconvenient and uncomfortable working positions, are all required only to ensure no air is present in front of the plunger inside the prepared syringe. These are the steps of having to hold the vial upside down and continuously having to ensure the tip of the needle is covered by fluid in the vial during preparation of a syringe for injection. Even specially designed vial adapters for maximising the amount that can be drawn from a vial and increase the accuracy by reducing the variation experienced in syringe filling, are all based on the assumed requirement of having no air in front of the plunger inside the filled syringe, neither as small bubbles in the fluid or as a single bubble at a predetermined position.

The claimed invention is based on reducing loss and variations in dose size, by using the principal of an air pocket stored behind the liquid drug, being used to displace and push out the liquid drug that would otherwise remain in the dead space of the syringe and needle, as well as the principal of calibration of the volume indications on the particular syringe used.

Thus, it is commonly regarded by the skilled person as an unavoidable necessity to bleed out air already present in the dead space of a syringe during or after filling. Hence, the idea of deliberately introducing a pocket of air even exceeding the dead space of the syringe and ensuring the presence of said pocket of air until the drug or vaccine has been injected into the person to receive the treatment, must be considered novel and cannot be claimed to be obvious to the skilled person. As vial adapters to increase the amount of drug usable from a vial is already being manufactured and marketed, and vaccines are given also on a commercial basis, the method described in this document and the embodiments of tools that may be used in aiding in using the claimed method must be considered patentable.

To provide an overview of the method, an embodiment of the claimed invention is described below as a detailed step-by-step instruction of the method being used in the context of a standard syringe.

Step 1 : Getting the Vial Ready

Preparation of the vial:

• Vial is prepared according to manufacturer’s instructions regard- ing dilution and agitation/suspension.

• Vial is centrifuged to ensure all fluid is at the bottom of the vial and no drops are sticking to the inside of the top or the inner surface of the glass.

• Cap on vial is removed.

• The rubber top of the vial is wiped clean with an alcohol pad.

• The vial is tilted at an angled surface.

• The vial is fitted with and air inlet to prevent vacuum.

• The vial is fitted with a drug outlet, such that drug is taken from the lowest area of the vial and exits through and opening with means of detachable connection with a syringe.

Step 2: Getting the Syringe Ready

Preparation of the syringe:

• With the cap still on, the plunger is pulled back to the line indicating the volume of the expected combined dead space of the syringe and the injection needle to be used. The selected volume will be referred to as “Air Set Value” in the following. This fills the syringe with air required to flush all drug/vaccine out during injection.

• The cap of the syringe is removed and the syringe is connected to the drug outlet fitted in the vial.

Step 3: Filling the Syringe with Drug or Vaccine

To ensure best possible accuracy and utilization of the given amount of drug or vaccine in a vial, a calibration of set values should be performed. This is an important prerequisite if using a syringe not designed specifically for air flushing (volume indications), but should also be performed even if not using air flushing, since the accuracy of volume indication may vary slightly between syringe types and brands.

An empty syringe have to be weighed and then be overfilled by pulling the plunger back the number of indications nominally required. If the required dose size is 0,3ml and the plunger is pulled back to 0,05ml prior to filling to compensate for dead space by air flushing, the plunger should be pulled back to 0,05+0, 3=0, 35ml when drawing drug into the syringe. The sy- ringe is weighed again and small amounts are expelled between re-weighing, until contents determined by weight is achieved. The position of the boundary between fluid and air in front of the plunger is determined and set as “Target Value” to be used.

• The plunger is pulled back and drug/vaccine is being drawn into the syringe in front of the plunger and separated from the plunger by a pocket of air. The boundary between fluid and air moves back with the plunger and the plunger is pulled back until boundary between fluid and air reaches the “Target Value”.

• The syringe is disconnected from the outlet in the vial.

• The injection needle to be used may be mounted with the protective cap fitted or the syringe may be capped without an injection needle fitted.

• The syringe is placed in a fixture in an upright or angled position of 0-25 degrees from vertical, to ensure air pocket stays on top of fluid during transportation and handling.

Step 4: Injection

• If the prepared syringe is capped, but not fitted with an injection needle, the cap is removed and an injection needle is mounted on the syringe.

• The cover of the injection needle is removed and the injection needle is inserted at the location of injection in an angle of 0-30 degrees from vertical.

• The plunger is pushed forward until the plunger reach the plunger end-of-travel. Thereby the drug/vaccine is pushed out of the syringe and into the needle by the pocket of air in front of the plunger. As the syringe is emptied of fluid, the air will push the remaining fluid in the needle and needle socket out and into the individual receiving the injection, without leaving drug/vaccine in the dead space of the system. The dead space of the system will then be filled with air from the air pocket.

• The needle is extracted from the site of injection and the needle cover is fitted on the used needle. • The used syringe and needle are disposed.

In an alternative embodiment, the order of steps 2 and 3 above is reversed. In such a method the syringe is first filled with drug/vaccine and subsequently with the air-pocket. The syringe is then manipulated to position the air-pocket behind the drug/vaccine, such as in between the plunger and the drug/vaccine. Such an alternative method may be carried out with a Step 1 of preparing the vial as set forth above, but it can also be carried out similarly to the known best practice as described herein, i.e. with the vial upside down and needle pointed up. Suitably the alternative method may be used when filling the syringe arranged such that a central axis of the syringe is within 30 degrees of vertical and with the front end of the syringe pointing upward.

The step of manipulating the air-pocket to a position behind the drug/vaccine can comprise one or more of arranging the syringe with the central axis within 30 degrees of vertical, with the front end pointing downwards; flicking the syringe; tapping the syringe with a utensil or finger and shaking the syringe. For some vaccines/drugs such manipulation should be carried out in a gentle manner, as they can be sensitive to mechanical forces such as shear.

When filling the syringe according to this alternative method, the “Target Value” should be read by the boundary between the plunger and the liquid, such as drug/vaccine.

In another embodiment of the invention there is provided a method for providing an amount of liquid substance and volume of fluid behind said liquid substance inside a syringe housing comprising the steps of:

- providing a syringe having a syringe housing extending in an axial direction, a plunger, and a needle unit, the needle unit comprising a cannula , the needle unit being attached or detachably attached to the syringe housing , an axial front end of the syringe being at the needle unit and an axial rear end of the syringe being the end opposite the front end;

- providing an amount of liquid substance and a volume of fluid inside the syringe housing, wherein the volume of fluid is provided behind the liquid substance as seen in the axial direction from the front end toward the rear end of the syringe, wherein the liquid substance and the fluid are immiscible or the fluid is a gas; wherein the step of providing the amount of liquid substance and the volume of fluid inside the syringe housing, comprises:

- providing the volume of fluid in a dead-space of the syringe; and then

- drawing liquid substance into the syringe from a liquid substance reservoir by pulling back the plunger toward the rear end of the syringe, thereby providing the amount of liquid substance in the syringe, such that the volume of fluid which was previously provided in the dead-space, is provided behind the liquid substance.

In such a method the volume of fluid is not removed from the deadspace prior to drawing in the liquid substance and the fluid occupying the dead-space creates the air-pocket behind the liquid substance.

Suitably the fluid is air. Providing a volume of fluid in the dead-space may be achieved by the plunger being in its fully inserted position, where the plunger is positioned at the front end of the syringe housing. Suitably the liquid is drawn in with the central axis of the syringe being positioned within 30 degrees of vertical with the front end pointing downwards.

Turning now to the aspects of the invention related to dose extraction aids and methods related thereto.

In a fourth aspect of the invention the objects mentioned in the introduction and further objects are achieved with a dose extraction aid of the kind mentioned in the introduction, wherein the vial axis is inclined in relation to the base surface, wherein the vial holder is configured for holding the vial in a position where the opening of the vial is further from the base surface than the exterior bottom surface of the vial, and wherein the dose extraction aid further comprises a ventilation unit holder configured for holding a ventilation unit comprising a cannula for piercing the septum of the vial arranged in the vial holder to allow air into the vial, where said ventilation unit holder defines a ventilation axis, and where, when the ventilation unit is arranged in the venti- lation unit holder, at least a section of the cannula of the ventilation unit coincides with the ventilation axis.

The vial holder being configured for holding the vial in a position, where the opening of the vial is further from the base surface than the exterior bottom surface of the vial, means that the vial is positioned with the opening facings upwards in a vertical direction in the mounted state. It has long been standard practice to arrange the vial upside-down when extracting a dose of liquid since it make it easy to see the liquid level inside the vial and since the cannula of the extraction unit would then not have to be inserted very far into the vial. Air in the syringe can be an issue for some types of administration, such as intravenous injection. The standard practice of extracting liquid from an upside-down vial is also used as it allows for removing any air initially present in the syringe as it will place itself above the liquid withdrawn into the syringe. Hence the operator first has to extract an amount of liquid and discharge it back into the vial, such that any air initially present in the syringe, hub or cannula is expelled into the vial, and subsequently a liquid dose is extracted from the vial. Furthermore, if any air is by accident extracted together with the liquid, it will end up at the top of the syringe closest to the vial and can easily be discharged back into the vial by reversing the plunger of syringe, without having to empty the entire syringe or discarding the extracted dose. Typically, the scale provided on the syringe is used to extract the correct dose from a vial. However, the scale provided on the syringe accounts for the dead volume of the syringe, hub and cannula. Essentially, the dead volume is equal to the volume of liquid left in the syringe, hub and cannula after discharge when the plunger of the syringe is in its bottom position, i.e. fully inserted in the syringe. Hence, the scale accounts for the dead volume which means that extracting a dose entails extracting a liquid volume which is greater than the intended dose, and even for low dead volume syringes this can be a significant contribution to inefficient use of the contents of the vial, especially as the number of doses in a vial increases, compounding the problem. Recent experiments, however, have shown that by keeping the vial with the opening facing upwards, the small amount of air, which is present in the cannula and possibly in the hub before extraction of the liquid begins, will end up between the extracted liquid and the plunger of the syringe. This means that when the liquid is subsequently administered to a human or animal patient, the air present between plunger and extracted liquid will enter the dead volume as the plunger approaches its bottom position, discharging liquid from the dead volume. In this way the amount of liquid remaining in the syringe, hub and cannula after discharge will be reduced, as described in relation to first second and third aspect of the invention. The risk of small amounts of air being injected into the patient is considered acceptable or even advantageous for intramuscular injection as it will make sure that all of the liquid leaves the needle and is not tracked back through subcutaneous tissue as the needle is withdrawn. In some applications, such as the methods according to first, second and third aspects of the invention, it may be advantageous provide additional air, compared to the dead volume, between the extracted liquid and the plunger of the syringe to ensure all liquid present in the hub and cannula is expelled. Additional air can prevent effects such as compression of the air and/or air channeling through the remaining liquid rather than displacing it, from the reducing the amount of the liquid discharged from the dead-volume. In this way, using the dose extraction aid allows a higher percentage of the liquid in a vial to be extracted. A further advantage of keeping the vial with the opening facing upwards is that any air present will be positioned in the advantageous position between the plunger and extracted liquid already during extraction of the dose. While air can be introduced into the syringe using the standard practice of keeping the vial upside down by subsequent flipping of the syringe to rearrange the air pocket, this has proven to be difficult in practice where vigorous shaking or tapping of the syringe has been required to relocated the air pocket. Presumably this is due to the syringes typically having small volumes, where surface tension or other forces hinder movement of the air-pocket. As some medicines are sensitive to mechanical agitation or shear, the dose extraction aid ensuring the correct placement of the air pocket from the onset is an advantage. A further advantage of keeping the vial with the opening facing upwards is that when the vial is almost empty, the remaining liquid will be visible at the bottom of the vial, whereas it may be hidden by the cap or by reflections caused by the shape of the neck of the vial when the vial is held upside-down. The extraction aid reduces strenuous working positions for the human operator as the dose extraction aid can be placed on a table or work bench, allowing a comfortable working position for human operator. As the dose extraction aid keeps the vial, extraction unit and ventilation unit in place, the human operator can focus on operating the syringe and extracting the correct dose.

The fact that the vial axis is inclined in relation to the base surface means that when a vial is arranged in the vial holder, the central axis of the vial is inclined in relation to a vertical plane and the bottom plane is inclined in relation to a horizontal plane. The vial axis may for example extend at an angle of 20-70 degrees, preferably 30-65 degrees, still more preferred 45-60 degrees in relation to the base surface. In combination these features result in the liquid inside the vial being urged towards the joint between the bottom and a side of the vial. As vials usually have a circular cross-sectional shape this means that when the vial is almost empty, the remaining liquid will be collected at the interior joint between the bottom and the side of the vial under the influence of gravity. This makes it easier to extract the remaining liquid compared to if the central axis of the vial was vertical and the remaining liquid spread out over the bottom of the vial. In order to allow the tip of the cannula of the extraction unit to also be located at the interior joint between the bottom and the side of the vial, the extraction axis is preferably inclined in relation to the vial axis, in one embodiment substantially perpendicular to the base surface. Making the extraction axis substantially perpendicular to the base surface will usually entail that the barrel of the syringe will be oriented vertically when the dose extraction aid is in use. This in turn means that the surface of the liquid inside the syringe will be horizontal, which will facilitate the determination of the volume of the dose extracted from the vial. For this reason alone, it is presently considered advantageous that the extraction axis is perpendicular to the base surface, but it is of course possible to compensate of an inclination of the syringe by appropriate calculations. Depending on the angle between the vial axis and the extraction axis and on the length of the cannula of the extraction unit relative to the height of the vial, the inclination of the vial axis may result in the cannula of the extraction unit coming into contact with the interior side surface of the vial during insertion into the vial. If the insertion is then continued, the cannula will bend, and the tip of the cannula will follow the interior side surface of the vial until reaching the interior joint between the bottom and the side of the vial. In this way the tip of the cannula will end up where the last of the liquid contained in the vial will collect under the influence of gravity. The exact path followed by the tip of the cannula will depend on several factors such as the shape of the vial and the flexibility of the cannula, but as both vials and cannulas are highly standardized products the optimal angle of the inclination of the vial axis and insertion depth of the extraction unit case be determined by a few simple experiments.

It is noted that the wording that “at least a section of the cannula of the extraction unit coincides with the extraction axis” is to be understood in the context of the potential for bending the cannula. While the entire cannula will usually coincide with the extraction axis in the initial unbend state, only the section of the cannula closest to the hub will coincide with the extraction in the bent state. Similarly, considerations apply the cannula of the ventilation unit and the ventilation axis. It is further noted that while extraction unit is generally described herein as consisting of the cannula and hub, it is understood that it could further comprise the syringe and/or other elements.

When using a bevel-tip cannula it is presently considered advantageous that the opening of the cannula faces the interior side surface of the vial. To ensure that this is the case the extraction unit holder may be configured for preventing a rotation of the hub of the extraction unit during insertion into the vial and during extraction liquid from the vial.

The presence of the ventilation unit holder allows for a ventilation unit to be arranged in a well-defined and controlled position in relation both to the vial and to the extraction unit. This in turn allows a ventilation of the space inside the vial, preventing the formation of an under-pressure as liquid is ex- tracted from the vial, which is particularly advantageous when several doses are to be retracted from one vial shortly after each other. An under-pressure might potentially result in it becoming difficult to extract all of the liquid from the vial and/or make it difficult to extract the precise volume needed for a dose. As the cannula of the ventilation unit should preferably not come into contact with the liquid inside the vial, the ventilation axis may extend at an angle of 10-45 degrees in relation to the base surface and at an angle of 20- 60 degrees in relation to the vial axis.

At least one of the vial holder, the extraction unit holder, and the ventilation unit holder preferably comprises an open-sided support member, such as a horse shoe-shaped rest having arms extending on either side of the vial, extraction unit or ventilation unit, respectively. This will facilitate the insertion and removal of the vial, extraction unit and/or ventilation unit, and arms of the support member may be elastic to retain the vial, extraction unit and/or ventilation unit during use. An open-sided structure may also provide a dose extraction aid which is easy to clean.

Whereas the vial and the ventilation unit will usually be at rest during the extraction of liquid from the vial, the cannula and the hub of the extraction unit may be subject to some loads, particularly if the same cannula and hub is used for filling several syringes. It may therefore be advantageous that the extraction unit holder comprises an elastic support member configured for fixating the hub of the extraction unit at least during application and removal of a syringe. The elastic support member may for example be elastic arms as described above, which can be forced together by hand and temporarily fixate the hub between them.

In one embodiment, the vial holder comprises a first support surface extending substantially in parallel to the vial axis for supporting a side of the vial extending substantially parallel to the central axis of the vial and a second support surface extending substantially perpendicular to the vial axis for supporting the exterior bottom surface of the vial. In this way a structurally simple and easy to use cradle-like support is provided for the vial. The first support surface may be concave with a curvature corresponding to the outer shape of the vial. Likewise, the second support surface may be provided with one or more projections or recesses allowing it to contribute to a correct positioning of the vial. As an example, the bottom surface of some vials is concave, and the second support surface may then be convex so that that vial will automatically be centred on the second support surface under the influence of gravity.

Also, or alternatively, the vial holder may comprise a neck rest configured for supporting a neck section of the vial. If the dose extraction aid is to be used with vials of different sizes, it may be advantageous to support the vials only by a neck rest or by a neck rest and a first support surface as described above so that all vials are located with the opening at substantially the same position.

In one embodiment the vial holder, the extraction needle unit, and ventilation unit holder form part of an attachable holder unit which can be attached to the base unit of the dose extraction aid. The attachable holder unit allows an operator to arrange the vial, the extraction needle unit, and the ventilation unit in the respective holders prior to attaching the holder unit to the base unit. This may for example be advantageous in that it allows one operator to prepare holder units with vials, extraction needle unit, and ventilation units, while another operator extracts doses from a vial held in a holder unit previously prepared, thus potentially optimizing workflows. Another advantage may be that the operator preparing the attachable holder unit may have a greater degree of freedom with respect to arranging the holder unit in an optimal position for inserting each of the vial, the extraction unit and the ventilation unit. The attachable holder unit may be a disposable unit, which can be discarded after the vial has been emptied, thereby reducing the risk of needlestick injuries as both cannulas will remain within the vial.

In one embodiment the dose extraction aid further comprises a camera unit holder arranged so that the camera may record the liquid level inside the syringe during extraction from the vial. The liquid level inside the syringe may be difficult to see with the naked eye, particularly if the liquid is uncoloured and transparent, and the camera unit may then be used for displaying it, either in an enlarged view or simply at a location, which is more convenient. It is even possibly to connect the camera to a computer loaded with an image recognition software so that the computer may determine when a desired volume has been reached.

The camera unit may for example be a mobile telephone or a video camera. It may be recording continuously, at intervals, or upon manual activation. The recordings may be saved or only shown as live images.

The camera unit holder may be adjustable in at least one direction to allow adaptation to different uses, for example to different syringe sizes or dose volume.

Further or alternatively, the dose extraction aid may comprise at least one mirror allowing a human operator or a camera unit to read the liquid level in the syringe from an alternative angle.

Further or alternatively, the dose extraction aid may comprise a screen extending substantially in parallel to the extraction axis behind the syringe. The screen may help a human operator or a camera unit to read the liquid level in the syringe by providing an optimal background colour or pattern. Also or alternatively, the screen may be provided with a shape or pattern indicating the intended liquid level in the syringe when the correct dose volume has been extracted and/or helping a camera unit to focus on the correct section of the syringe.

In a fifth aspect of the invention at least the objects of the invention described above are achieved with a method for extracting a liquid from a vial comprising the steps of:

A) providing a dose extraction aid having a base unit, a vial holder (20), an extraction unit holder, and a ventilation unit holder,

B) arranging the dose extraction aid with a base surface of the base unit on a horizontal support surface,

C) arranging a vial in the vial holder, said vial having an opening covered by a cap with a septum and an exterior bottom surface opposite the opening, a central axis of the vial extending from the opening to the exterior bottom surface perpendicular to a bottom plane defined by said bottom surface, such that the central axis of the vial extends coincides with a vial axis of the vial holder, and such that the central axis of the vial is inclined in relation to the base surface, and such that the opening of the vial is further from the base surface than the exterior bottom surface of the vial,

D) arranging an extraction unit in the extraction unit holder, such that a cannula of the extraction unit extends through the septum of the vial into a liquid contained in the vial and such that at least a section of the cannula of the extraction unit closest to a hub of the extraction unit for connecting the cannula to a syringe coincides with an extraction axis of the extraction unit holder,

E) arranging a ventilation unit in the ventilation unit holder such that a cannula of the ventilation unit pierces the septum of the vial, allowing air into the vial, and such that at least a section of the cannula of the ventilation unit coincides with a ventilation axis of the ventilation unit holder, and

F) connecting a syringe to the hub of the extraction unit, and

G) extracting liquid from the vial into the syringe via the cannula of the extraction unit.

As described above it is presently considered advantageous that the cannula of the extraction unit comes into contact with an interior side surface of the vial during step D and is bent during the further insertion of the cannula into the vial.

Likewise, it is considered advantageous that, during step D, the cannula of the extraction unit comes into contact with an interior bottom surface of the vial. This applies regardless if the cannula is bent or not.

If using an attachable holder unit as described above the sequence of steps A-F may be different than described above and/or some of these steps may be divided into sub-steps. As an example, step B may initially include arranging only the base unit of the dose extraction aid on the support surface and the attachable holder unit may then be attached in a step H taking place before step G.

The embodiments and advantages described above with reference to the fourth aspect of the invention also applies to the fifth aspect of the invention unless otherwise stated. It is thus appreciated that the dose extraction aid as described herein can be used in methods of operating a syringe as described herein, in particular in methods for providing an amount of liquid substance and volume of fluid behind said liquid substance inside a syringe housing.

Detailed description

In the following the invention is described in greater detail based on non-limiting exemplary embodiments and with reference to the drawings, where Figs 1 -6 are provided to illustrate the methods for operating the syringe and Figs. 7 to 20 are provided to illustrate the dose extraction aid and related methods.

Fig. 1 a-d: Illustrations of filling and dead space in syringe using current best practice.

Fig. 2a-e: Illustrations of injection with syringe provided with a flushing air pocket.

Fig. 3a-e: Illustrations of providing a syringe with an air pocket and filling.

Fig. 4a-e: Illustrations of calibration of scale on syringe.

Fig. 5a-d: Illustrations of vial prepared for filling and providing syringe with air pocket.

Fig. 6: Illustration of filling a syringe provided with air pocket from I vial.

Fig. 7 is a perspective view of a dose extraction aid according to an embodiment of the invention alongside a vial, an extraction unit with a syringe, and a ventilation unit

Fig. 8 shows the dose extraction aid of Fig. 7 wherein the vial, extraction unit with the syringe and ventilation unit are arranged in the dose extraction aid,

Fig. 9 shows a cross-sectional view of Fig.8,

Fig. 10a and 10b show two front views of the dose extraction aid of Fig. 7,

Fig. 11 shows a front view of the dose extraction aid of Fig. 8, Fig. 12a-b shows cross-sectional views of vials, extraction unit and ventilation units arranged in a dose extraction aid without showing the dose ex-traction aid,

Fig. 13 show a perspective of another dose extraction aid according to the invention with an attachable holder unit,

Fig. 14 shows the dose extraction aid of Fig. 12 wherein the vial, extraction unit and ventilation unit and syringe is being arranged in the dose extraction aid,

Fig. 15 shows a perspective of another dose extraction aid according to the invention with a camera unit holder,

Fig. 16 shows the dose extraction aid of Fig. 15 with a camera unit arranged in the camera unit holder,

Fig. 17 shows additional views of the dose extraction aid of Fig. 15,

Fig. 18 shows another dose extraction aid according to the invention with a camera unit holder, a camera unit and an external display unit,

Fig. 19 shows another dose extraction aid according to the invention with a grip element, and

Fig. 20 shows another dose extraction aid according to the invention where the extraction unit holder holds the extraction unit by the syringe.

Methods for operating a syringe

In the following a detailed description of the method for operating a syringe according to the invention and embodiments is provided with reference to Figs. 1 to 6. The terms below are understood as set forth below in the context of the methods for operating a syringe and Figs. 1 to 6:

Front: Axial direction towards the needle end of a syringe.

Rear: Axial direction towards the plunger end of a syringe.

Behind: Further towards rear than the entity being behind of.

Top: End of vial with sealed opening in axial direction.

Bottom: Opposite end of top of vial in axial direction.

Drug: Medical drug, vaccine or other injectable liguid fluid.

Air: Atmospheric air or other gas. A novel and inventive feature of the claimed invention, is the introduction of a pocket of air behind the drug in a syringe, enabling virtually complete emptying of drug and needle during subsequent injection by flushing the system with air.

It should be noted that the invented method is NOT suitable for use with intravenous injections, as the introduction of air into the blood stream can be dangerous. The method is intended for subcutaneous and intermuscular injections, where the introduction of small amounts of air is harmless. To prevent the risk of accidently introducing air into the bloodstream, an oil or other immiscible liquid fluid may be used instead of air, as the purpose of the air is to introduce a working fluid to displace the remainder of drug otherwise left in the dead space of the system. If the drug degrades quickly when exposed to oxygen, an inert gas may be used, to allow longer handling time between filling the syringe and injection.

As ambient air will most often be used, although maybe filtered to prevent contamination, the term “air” us used throughout the description, although it should be understood that any fluid acceptable for injection in small amounts can be used, as long as the fluid has a lower density than the drug and liquids used must be immiscible with the drug. Oils based on soybean oil and safflower oil have been widely used with injectable substances for more than 40 years

When performing injections according to current best practise, a syringe is filled according to the procedure earlier described in this document, to avoid air anywhere in front of the plunger of the syringe. In fig. 1 b a cross section of a syringe (1 ), filled according the current requirements of no air in drug (101 ) is shown. The drug (101 ) fills the void (104) in the syringe housing (100) in front of the plunger (103) completely and contains no air or air bubbles, as required by current best practice. The drug (101 ) has been drawn into the void (104) through a needle unit (105) from a vial (not shown), by pulling back the plunger (103) using the plunger rod (106). The needle unit (105) consist of a cannula (107) fixed in a needle hub (108) that is detachably attached to the syringe housing tip (109). As the syringe (1 ) has been filled with drug (101 ) though the needle unit (105), the cannula (107) is also filled with drug (101 d) as well as the needle hub (108) is filled with drug (101 c).

It should be noted, that although a contents of 0,3ml is indicated (120), the syringe and needle unit contains more and more drug has been drawn from the vial, at the makings on a syringe indicates the injectable volume, assuming no change of needle.

After injection when the plunger (103) has been pushed to its end-of- travel as it is stopped by the front section (121 ) of the syringe housing (100), the drug (101 d) earlier located in the cannula (107) and the drug (101 c) earlier located in the needle hub (108) has been expelled along with the drug (101 b) in the syringe housing tip (109) and most of the drug (101 a) in the void (104) in front of the plunger (103). However, a small amount of the drug (101 e) earlier located in the void (104) is now located around the tip of the plunger (103) inside the syringe housing tip (109) and some is left in the needle hub (108) and in the cannula (017), as illustrated in fig. 1 c.

The expelled amount of drug (122) corresponding to the indicated volume (120) is shown in fig. 1 d, as well as the remaining drug (123) in the syringe housing tip (109) and the needle unit (105).

The remaining drug (123) in the syringe housing tip (109) and the needle unit (105) is the loss caused by dead space in the system. Although a syringe (1 ) as depicted is designed to minimise dead space and the dead space (101 d) of the cannula (107) is very small, the dead space (101 c) of the needle hub (108) amounts to about 40pl in a 1 ml syringe.

The difference in dead space from current best practice experienced using the invention, can be realised by comparison with the illustrations in fig. 2.

A syringe (200) provided with an injection needle unit (201 ) and an air pocket (202) behind the drug (203), in front of the plunger (204). In fig. 2a, the syringe is illustrated just prior to injection, where it has been fitted with an injection needle unit (201 ) and the cannula (206) and the needle hub (207) are therefore not filled with drug, as can be seen by the empty cavity (205) in the needle hub (207). Because the air pocket (202) is not separated from the drug (203) in this embodiment, the syringe (200) should be store and handled in an upright position, as indicated by the arrow, with the needle end pointing down, to prevent air pocket (202) from moving inside the drug (203).

As the plunger (204) is pushed to injected the drug (203), the cavity (205) and the cannula (206) is filled with drug (203) and drug starts to flow out of the cannula (206) as the plunger push the pocket of air (202) and the drug (203) in front of the air pocket (202), as shown in fig. 2b. The drug surface

(208) travels in front of the air pocket (202) from the main cavity of the syringe housing in fig. 2b and into the tip of the syringe housing in fig. 2c, as the drug leaves through the cannula (206). In fig. 2d the entire drug has just been injected, pushed out by the air pocket, that now fills the cavity in the needle hub (205), the syringe housing tip (210), the cannula (206) and a small cavity

(209) in front of the plunger (204). When the plunger (204) reach the end of travel as illustrated in fig. 2e, virtually all drug has been injected and all voids flushed by air.

To draw drug from a vial and into a syringe and provide the filled syringe with an air bubble as described and illustrated in fig. 2, the plunger (301 ) of an empty syringe is pulled back to a predetermined “Air Set Value” (302), based on the type of syringe used. This value determines the size of the air pocket behind the drug and should be set sufficiently large to prevent the tip of the plunger from penetrating the surface of the drug, even during handling, and sufficiently low to prevent small temperature variations to cause the air to expand enough to expel drug. In the example illustrated in fig. 3a, an “Air Set Value” (302) of 0,13ml is used. In fig. 3b the syringe is connected to a needle unit (303) in connection with the drug in I vial (not shown). As the plunger (301 ) is pulled back as in fig. 3c, drug (304) is drawn through the needle unit (303) and into the syringe (300), whereby a pocket of air (305) is trapped above the drug surface (306) below the plunger (301 ) with a clearance (307) between the drug surface (306) and the tip of the plunger (308) to allow handling without the plunger tip (308) penetrating the drug surface (306).

The plunger (301 ) is pulled back, drawing up drug (304) until the up- per surface of the drug (306) reaches the indication (309) corresponding to the “Target Value” determined for the particular type and brand of syringe (300) during calibration of the volume indications, as shown in fig. 3d.

The filled syringe (310) provided with a pocket of air (305) for flushing the dead space in fig. 3e can then be disconnected from the needle unit (303) in the vial (not shown) and be either capped or fitted with a capped injection needle. To prevent leaking due to temperature variations, the plunger can now be pulled back a little after filling and disconnection from the filling reservoir and thereby pull the drug surface a bit into the tip of the syringe. This will allow the air to expand a little without causing a leak.

The prepared syringe is then placed in a fixture keeping the needle end of the syringe down to ensure the air pocket stays on top of the drug.

In an alternative method according to the invention, liquid substance, such as drug/vaccine, is first drawn into the syringe and then air is drawn into the syringe and subsequently the syringe is manipulated to move the air- pocket to be positioned behind the liquid substance.

To minimise variations and increase accuracy of dose volume, the volume indications of the specific type, brand and in some cases, even batch of syringes to be used must be calibrated. In particular when using an air pocket for flushing, it is necessary to calibrate the volume indication scale of the syringe, as the volume indication scale is made under the assumption that the tip of the plunger displaces an amount of drug and thereby move the drug surface further up along the scale. To enable calibration of the volume indication scale on the syringe, the density of the drug to be used must be known and the weight of an empty syringe must be determined with sufficient accuracy. It should be noted, that the weight of the empty syringe must be determined with the appropriate needle fitting. If the drug is to be drawn from a vial with the needle to be used for injection as well, the needle must remain fitted during the initial weighing of the syringe and throughout the entire calibration procedure. If the drug is to be drawn with one needle fitted and another needle is later fitted for injection, the initial weighing of the syringe and all subsequent weighing’s must be perform with no needle fitted. In the illustrations of fig. 4, the syringe is to be filled by drawing through a long needle from a vial and a smaller injection needle is to be used during injection. The empty syringe is therefore weighed initially without a needle fitted.

A syringe is to be filled with a specific volume of drug and from the density of the drug and the weight of an empty syringe, it is determined the weight of a correctly filled syringe will be. In the illustrations of fig. 4, the syringe should be filled to deliver 0.3ml and the sum of the weight of the empty syringe and expected weight of 0,3ml drug is 16.8725g.

The syringe (400) is fitted with a needle unit (401 ) for drawing drug (402) from a vial (not shown). It is intended to use an air pocket (403) for flushing the dead space of syringe and injection needle and drug (402) is drawn into the syringe such that the drug surface (404) is at the indication of the intended dose size (405) or above (406), as shown in fig. 4a.

A small amount may be expelled, since the syringe was filled beyond the marking of the target dose size, as illustrated in fig. 4b. The syringe is removed from the needle (401 ) and the plunger (415) is pushed slightly to move the drug surface down to the indication corresponding to a value close to the intended volume (407). Any drug on the outer surfaces of the syringe is wiped off and the syringe is weighed and found to contain too much drug, as the first decimal of the weight (408) is too large. Slightly more drug is expelled, the outer surfaces of the syringe dried off and the syringe weighed again (409) and found to heavy. The process is continued, until the weight (410) is within acceptable tolerances from the intended weight, as in fig 4d and the position of the drug surface (414) on the volume indication scale of the syringe is noted (411 ).

A needle unit as intended for use during injection (413) is fitted and the content of the syringe is expelled (416) onto a scale and the weight (412) of the actually expelled drug is verified to be within acceptable tolerances. The indication (411 ) at which the drug surface (414) was placed at acceptance prior to verification is used as “Target Value” for the filling of the syringes for injection.

Drugs and vaccines are most often supplied in vials (500) consisting of a vial glass (501 ) with a sealing septum (502) covering the opening and secured by a flanging (503). Filling of the syringe must be done with the syringe in an upright position to maintain air pocket on top of drug in syringe. To enable drawing up drug from an almost empty vial, to utilise as much of the drug as possible, the vial must be tilted, as shown in fig. 5a. An angle a of 45° would be optimal in regards to maximizing liquid depth. However, the angle of the syringe (not shown) relative to vertical should preferably be less than 30°. Thus, the angles a and [3 will be a compromise between maximum fluid depth in the vial and as little tilt of the syringe as possible. The diameter of the vial neck and body, as well as the height of the vial will set limits of possible solutions and the best possible compromise will have to be determined based on the dimensions of the vial. The vial (500) may be fitted in a fixture (not shown) to maintain the correct angle during filling.

In the simplest solution, a drawing needle (504) for drawing up drug (506) from the vial (500) is fitted on a syringe (not shown) and the plunger is pulled back the number of indications corresponding to the dose size to be filled into the syringe. If an air bubble is to be introduced, the plunger should be pulled back further corresponding to the “Air Set Value”. The needle (504) on the syringe (not shown) is then inserted in the vial (500), penetrating the septum (502) and placed such that the tip of the needle is above the drug. The plunger of the syringe is then pushed forward to the “Air Set Value”, whereby air pressure in vial is increased to prevent vacuum. The needle (504) is then inserted into the drug (506) and placed as shown in fig. 5a. Drug can then be drawn into the syringe according to method described above. It should be noted that no air inlet needle (505) is used in this solution. Hence, the need of pressurising the vial prior to drawing up drug.

In an alternative solution, a longer drawing needle (504) with no syringe attached is fitted in the vial (500). A second and shorter needle (505) is fitted at an angle such that the tip is not submerged (5c and 5d) in the drug (506) in the vial (500) and placed in a plane offset from the plane in which the drawing needle (504) is placed, as shown in figs. 5b and 5d. Both needle may be guided and/or locked into position by a fixture (not shown) also fixating the vial (500) in the correct position and orientation. The air inlet needle (505) may be provided with a filter (not shown) to prevent contamination from entering the vial through the air inlet. Using a solution with a fitted air inlet needle (505) simplifies filling, as this solution does not require the operator to pull back plunger in syringe further than the air set value and insert a needle partially and apply pressure to the vial prior to drawing drug. Furthermore, this solution reduces needle handling and capping, whereby the risk of accidental stinging is reduced.

When using a solution with a drawing needle (603) and an air inlet needle (604) fitted in a vial (601 ) for filling the syringe (602), as illustrated in fig. 6, a fixture (not shown) may be used to guide and lock the needles in place in the vial (601 ), as well as secure the vial (601 ) in the best possible orientation. A syringe (602) can then be inserted in the socket/hub (605) of the drawing needle (603) and may be guided and supported by the structure of the fixture of the vial and needles. In fig. 6 the filling of a syringe (602) is illustrated. Special lighting may be set up as part of the working environment or be built-in to the fixture, to ease visibility of the boundary (606) between the drug (607) being drawn into the syringe and the air pocket (608) above the drug (607) in the syringe. Magnifying glass or cameras may also be fitted to further improve visibility and accuracy of reading the scale (609) on the syringe (602).

Apart from ensuring the integrity of an air pocket () above the drug () in the syringe () by drawing drug () up from a vial (), instead of the current best practice of drawing out drug from underneath a vial turned upside down, this method of filling greatly improves the working position of the operator and allows aiding fixtures and means for handling to be used. Thus, this filling method would be beneficial for the working environment of the operator and by easing the operators tasks, leaves the operator less prone to fatigue and exhaustion and fewer operator errors should be experienced, regardless of using a method of introducing an air bubble for flushing the dead space or not.

The embodiments illustrated and discussed in this specification are intended only to teach those skilled in the art how to make and use the invention. In describing embodiments of the invention, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected. The above-described embodiments of the invention may be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the claims, the invention may be practiced otherwise than as specifically described.

Dose extraction aid and related methods

In the following the dose extraction aid and related method is described with reference to Figs. 7 to 20 using reference numerals with a at the end.

Figs 7-11 show an embodiment of the dose extraction aid T. In Fig. 7 the dose extraction aid T is shown alongside a vial 200', an extraction unit 300' with a syringe 500', and a ventilation unit 400', and in Figs. 8 and 9 the vial, the extraction unit with the syringe, and the ventilation unit are arranged on the dose extraction aid.

The vial 200' shown is a crimp vial provided with a septum 20T and a cap 202', which covers an opening of the vial. In other vial types the septum is integrated in the cap. The vial 200' has an exterior bottom surface 203' and vial side 204', which in this case is a cylindrical surface. A central axis 200a' of the vial extends in a direction from the opening to the exterior bottom surface of the vial and is perpendicular to a bottom plane defined by the exterior bottom surface 203'. The extraction unit 300' is here shown with a syringe 500' which can be connected to a hub 30T of the extraction unit 300', which also has a cannula 302'. The ventilation unit 400' is here another needle unit having a cannula 402' and hub 40T. In the following the needle unit which consists of the hub 30T and cannula 302' is typically referred to as the extraction unit 300', but it is noted that the extraction unit can comprise further components such as the syringe 500' which can be connected to the hub 30T.

The dose extraction aid T is shown as it would be oriented during use with base surface 3' of a base unit 2' of the dose extraction aid resting on a horizontal support surface (not shown), such as workbench or table. The base unit 2' here has a flat base surface 3' allowing it to rest on the horizontal support surface as seen in Fig. 9, but the base surface 3' might also be constituted by feet attached to the base unit 2'.

The dose extraction aid T has a vial holder 20', which is configured to receive and hold the vial 200'. The vial holder 20' defines a vial axis 20a', and when the vial 200' is arranged in the vial holder 20' the central axis 200a' of the vial will coincide with the vial axis 20a'. As can be seen the vial axis 20a' is inclined in relation to the base surface 3' and is also inclined in relation to the horizontal plane and a vertical plane. The exterior bottom surface 203' of the vial will also be inclined in relation to the horizontal plane and a vertical plane. In this embodiment the vial holder 20' has an open-sided support member embodied by a horse-shoe shaped neck rest 2T, which is configured for supporting the neck 206' of the vial 200', a first support surface 22' for supporting the side 204' of the vial, and a second support surface 23' for supporting the exterior bottom surface 203' of the vial, and a top element 24'. The first support surface 22' extends substantially parallel to the vial axis 20a' and is a curved surface corresponding to the curvature of the vial 200'. The second support surface 23' and top element 24' extend substantially perpendicularly to the vial axis and the top element 24' is positioned further from the base surface 3' than the second support surface 23'. The first and second surfaces 22', 23', the top element 24', and the neck rest 2T delimit a vial spacing 25' in which the vial can be held in a cradle-like support. In Fig. 7 the vial holder 20' is configured such that the particular vial 200' shown will be supported by the neck rest 2T and first and second support surfaces 22', 23' when arranged in the vial holder 20'. The vial holder 20' can also be used for smaller vials. For example, vials of lesser height can be held by the neck rest 2T, optionally supported by the top element 24', but not by the second support surface 23'. The neck rest 2T is here shown as a horse-shoe shaped element with a diameter allowing the neck of the vial to be placed within it and allow a collar of the vial to rest upon the neck rest. The top element 24' has channels which allow access to the septum 201 ' of the vial when the vial 200' is arranged in the vial holder 200'. The space between the neck rest 2T and top element 24' is adapted for accommodating the vial cap 202'.

The dose extraction aid T further has an extraction unit holder 30' disposed above the vial holder 20'. The extraction unit holder 30' is configured to receive and hold the extraction unit 300' in a position wherein the cannula 302' of the extraction unit pierces the septum 20T of the vial and extends into the liquid inside the vial 200'. The extraction unit holder 30' is adapted to receive and engage the hub 30T of the extraction unit to keep the extraction unit 300' in place. The extraction unit holder defines an extraction axis 30a', which in Fig. 7 is substantially vertical, i.e. substantially perpendicular to the base surface 3', and inclined in relation to the vial axis 20a'. In this embodiment the extraction unit holder 30' has a first support element 3T and a second support element 32' which are spaced apart along the extraction axis 30a'. The first support element 3T is adapted to engage a wide part of the hub 30T distal from the cannula 302', and the second support element 32' is adapted to engage a smaller part of the hub proximal to the cannula 302', by which engagement the extraction unit 300' is held in the extraction unit holder 30'. The extraction unit 300' is mounted in the extraction unit holder 30' by introducing it along the extraction axis whereby the cannula 302' of the extraction unit is guided through the septum 20T of the vial, until the hub 30T engages the second support element 32' of the extraction unit holder 30'. In this way the extraction unit is kept in place and mounted correctly in the dose extraction aid and thus also correctly in the vial 200'. When the extraction unit 300' is mounted in the dose extraction aid T at least a section of the cannula 302' of the extraction unit 300', which is closest to the hub 30T, will extend along the extraction axis 30a'. When the syringe 500' is attached to the hub 30T, the syringe will extend along the extraction axis 30a' as shown in Fig. 8. The extraction unit holder 30' has an open-sided structure and will thus not engage the entire circumference of the hub 30T, allowing it to be removed easily. The open-sided structure similarly allows for easy cleaning of the extraction unit holder 30'. The extraction unit holder 30' may be provided with an elastic support member (not shown) for engaging the extraction unit 300' to prevent rotation or axial movement during use of a syringe 500'. It is presently preferred that the extraction unit holder 300' engages the hub 301' of the extraction unit to keep it in place as shown in the embodiment of Fig. 7-11 , however, it could alternatively or additionally also hold the extraction unit by supporting the syringe 500' connected to the hub 301'. In such an embodiment, the extraction unit 300' could be said to comprise the cannula 302', hub 301' and syringe 500'.

The dose extraction aid further has a ventilation unit holder 40' disposed above the vial holder 20'. The ventilation unit holder 40' is configured to receive and hold the ventilation unit 400' in a position wherein the cannula 402' of the ventilation unit 400' pierces the septum 20T of the vial creating a ventilation path to a headspace of the vial (not shown in Figs 7-9). The ventilation unit holder 40' defines a ventilation axis 40a', which in this embodiment is slightly inclined in relation to the vial axis 20a'. In Fig. 7 the ventilation unit 400' is a needle unit and the ventilation unit holder 40' is an element having an internal spacing with a cone shape corresponding to the exterior shape of the hub 40T of the ventilation unit. The ventilation unit holder 40' is provided with a recess 4T for receiving a flange 403' of the hub 40T. The ventilation unit 400' is mounted in the ventilation unit holder 40' by introducing it along the ventilation axis 40a' whereby the cannula 402' of the ventilation unit is guided through the septum 20T of the vial, until the hub 40T engages the internal spacing and recess 4T of the ventilation unit holder. In this way the ventilation unit 400' is held in place and mounted correctly in the dose extraction aid T and thus also correctly in the vial 200'. The position and inclination of the ventilation unit holder 40' shown in Fig. 7 is such that the cannula 402' of the ventilation unit will be positioned in the headspace of vial 200' having clearance to the liquid surface. The ventilation unit holder 40' here has an open-sided structure and will thus not engage the entire circumference of the needle hub 40T, allowing it to be removed easily. The open-sided structure similarly allows for easy cleaning of the ventilation unit holder 40'.

The dose extraction aid T is used by inserting the vial 200' in the vial holder 20', whereby it will be positioned at an incline in relation to the base surface 3'. Then the ventilation unit 400' is mounted in the ventilation unit holder 40' by introducing it along the ventilation axis 40a', the cannula 402' of the ventilation unit pierces the septum 20T of the vial and enters the headspace of the vial. The correct position of the ventilation unit 400' is ensured by the ventilation unit holder 40' engaging the ventilation unit 400'. The extraction unit 300' is mounted in the extraction unit holder 30' by introducing it along the extraction axis 30a', whereby the cannula 302' of the extraction unit pierces the septum 201 ' of the vial and enters the liquid of the vial 200'. The tip of the cannula is thus positioned at the interior joint 205' between the interior wall and the interior bottom surface of the vial 200', see Fig, 9. The position of the tip of the cannula inside the vial is determined by the vial inclination, i.e. vial axis 20a', and the extraction axis 30a'. The syringe 500' may then be attached to the extraction unit 300' and used to withdraw or extract liquid from the vial. The syringe 500' could also be attached to the hub 30T prior to mounting the extraction unit 300' in the extraction unit holder. As liquid is withdrawn the liquid level in the vial will drop, but due to the vial inclination liquid will collect at the bottommost part of the interior joint 205' as illustrated in Fig. 12b and 12c, which results in a higher liquid level compared to the same amount of liquid in the vial in an upright position. The higher liquid level allows more liquid to be withdrawn from the vial. The ventilation unit 400' may be mounted before or after the extraction unit 300'. If the vial contains more than one dose, the extraction unit 300' can be kept in the dose extraction aid T and in the vial 200' between withdrawal of individual doses from the vial and only the syringe 500' is exchanged. It is presently preferred that the extraction unit 300' is kept in the dose extraction aid T for several or all dose extractions from a vial 200', so as to minimize loss of liquid contained in the hub 30T and cannula 302'. However it is also conceivable that the extraction unit 300' is replaced along with the syringe between individual dose withdrawals, which could be advantageous in some applications e.g. if the liquid in the vial is inexpensive or readily available As can be seen inclination of the vial 200' when arranged on the dose extraction aid T also provides a comfortable viewing angle for the operator observing the liquid in the vial and in the syringe. In the Fig. 7 the vial holder 20', ventilation unit holder 40' and extraction unit holder 30' are configured to receive and hold the particular extraction unit 300', ventilation unit 400' and vial 200' shown in Fig. 7. It will be appreciated that for other types of the ventilation unit, extraction unit and vials, the holders can be adapted accordingly if necessary.

Fig. 8 shows the embodiment of Fig. 7, wherein the vial 200' is arranged and held in the vial holder 20', the extraction unit 300' with the syringe 500' is arranged and held in the extraction unit holder 30', and the ventilation unit 400' is arranged and held in the ventilation unit holder 40'. As can be seen the syringe 500' extends along the extraction axis 30a', which extends substantially vertically, allowing the operator to observe a level liquid level in the syringe 500'. The vial 200' fits in the vial spacing 25' and is supported by the first and second support surfaces 22', 23' and the neck rest 2T. The central axis 200a' of the vial coincides with the vial axis 20a' of the vial holder 20' and the opening of the vial provided with a cap 202' with a septum 20T is further from the base surface than the exterior bottom surface 203' of the vial. The open structure of the vial holder 20', allows unhindered view of the vial 200' arranged therein to the operator allowing him or her to see the liquid level in the vial.

An air filter may be attached to the ventilation unit 400' to filter the air flow ventilating the vial 200'.

Fig. 9 shows a cross-sectional view of the dose extraction aid T of Fig. 8 as seen from the side. The cross-section is at the plane of the ventilation axis 40a'. As can be seen the vial axis 20' and central axis 200a' of the vial coincide and are inclined in relation to the base surface 3' and form a vial angle 9' which in this embodiment is about 55 degrees. Hence the central axis of the vial is inclined in relation to the horizontal plane the vertical plane. The syringe 500' extends along the extraction axis 30a' which is substantially vertical. The section of the cannula 302' of the extraction unit which is closest the hub 30T also extends along the extraction axis 40a'. The cannula 302' is seen to be deflected off the interior wall of the vial 200' such that the tip 303' of the cannula of the extraction unit reaches the interior joint 205' of the vial 200'. The ventilation axis 40a' is seen to form an angle 5' of about 30 degrees with the horizontal plane and the base surface 3', corresponding to an angle of about 25 degrees in relation to the vial axis 20a'. In Fig. 9 the base surface 3' is seen to be extend along a periphery of the base unit 2'. The base surface 3' extends in base surface plane and the inclination of the axis of the dose extraction aid T may also be determined in relation to this base surface plane.

Fig. 10a shows the dose extraction aid T of Fig. 7 in a front view as seen parallel to the horizontal plane. As can be seen the internal spacing 25' has a shape corresponding to the vial 200', with the first support surface 22' extending parallel with the vial axis 20a' the neck rest 2T having a shape corresponding to the neck of the vial and a transition section of the vial holder 20' matched the shape of the shoulders of the vial. The top element 24' has channels 26', 27' for allowing access for the cannula 302' of the extraction unit 300' and the cannula 402' of the ventilation unit 400' respectively to the septum of the vial when introducing along the extraction axis 30a' and ventilation axis 40a' respectively. As can be seen the extraction unit holder 30' and ventilation unit holder 40' are offset such that the extraction axis 30a' and ventilation axis 40a' do not intersect.

Fig. 10b shows the dose extraction aid T of Fig. 7 in a front view as seen perpendicularly to the vial axis. In this view the offset between extraction unit holder 30' and ventilation unit holder 40' is seen. The figure shows the cone (frustrum) shaped internal spacing of the ventilation unit holder 40' which engages the hub 40T of the ventilation unit 400'. The first support element 3T of the extraction unit holder 30' also has a frustrum shaped surface for engaging the hub 30T of the extraction unit 300'.

Fig. 11 shows a front view of the dose extraction aid with the vial, the extraction unit, the ventilation unit and the syringe mounted thereon as in Fig. 8 to 9 in the front view of Fig. 10a.

Fig. 12a to 12c each show a vial 200' along with an extraction unit 300' and in Fig. 12a and 12c also a ventilation unit 400' as they could appear when arranged in different dose extraction aids according to the invention. The dose extraction aids themselves have here been left out of the figures to show the details of the vial 200', extraction unit 300' and ventilation unit 400' more clearly. The horizontal plane is indicated by plane H'.

Fig. 12a-b show a vial with its central axis 200a' coinciding with the vial axis 20a', forming angle 9' with the horizontal plane. The exterior bottom surface 203' defines a bottom plane P' which forms an angle a' with horizontal. In this embodiment the extraction unit 300' extend along the extraction axis 30a' and the extraction axis 30a' is inclined at an angle P' in relation the vertical direction D', the vertical direction being perpendicular to the horizontal plane H'. In this embodiment the angle a' is about 35 degrees, the angle 9' is about 55 degrees and the angle P' is about 20 degrees. In this embodiment the vial holder 20a' and extraction unit holder 30a' are configured such that the angles 9' and P' allows cannula 302' to extend linearly to the interior joint 205' of the vial 200'. Fig. 12a shows the vial 200' in an initial full state where the liquid level 206' is high in the vial 200'. As liquid is extracted from the vial 200' by way of extraction unit 300' the liquid level drops as shown in Fig. 12b. Due to the inclination of the vial axis 20a' the remaining liquid will collect at the bottommost part of the interior joint 205', which allows more liquid to be extracted compared to a situation where the central axis 200a' of the vial 200' is kept parallel to vertical.

In the embodiment of Fig. 12a and 12b the syringe 500' will not be extending in a vertical direction as in Fig. 8 and 9, and the indicators on the syringe (not shown) will thus not provide an accurate indication of the extracted liquid amount, hence liquid should be withdrawn to predetermined mark adjusted to the angle P'. The predetermined marking can be determined by calibrating an extraction in the vial device holder as described below.

The predetermined marking may be determined by a calibration procedure for the particular syringe type. An empty syringe is weighed to obtain a syringe weight. The desired dose weight is selected. The syringe is then filled to an initial level using a dose extraction aid according to the invention. The filled syringe is weighed and if the weight accounting for syringe weight is larger than the desired dose weight, the syringe is iteratively emptied to reach the desired dose weight. The syringe is then mounted in the dose extraction aid and the liquid level is noted as the predetermined marking. The syringe is retrieved from the dose extraction aid the content is discharged onto a weight, to verify whether the discharged amount corresponds to the desired dose. If the discharged amount deviate from the desired dose, the deviation in weight can be added to the target weight and the procedure is repeated. The predetermined mark may be used when extracting a dose from the vial.

The cannula 402' of the ventilation unit 400' is seen to be positioned in the headspace of the vial 200', the headspace being the air between liquid level 206' and septum 20T.

Fig. 12 shows a vial in the same situation as Fig. 12, but as it would be oriented in the dose extraction aid in Figs 7-11 wherein the vial holder 20a' and extraction need unit holder 30a' are configured such that the angles 9' and P' cause the cannula 302' to deflect off the interior side wall 206' of the vial 200' and extend in curved path to the interior joint 205'. In this embodiment only a section 304' of the cannula 302' which is closest to the hub 30T extends along the extraction axis 30a' in the inserted state of the extraction unit. As can be seen, the hub 40T extends along the extraction axis. This allows the extraction axis 30a' to be substantially vertical whereby a syringe attached the extraction unit 300' will be substantially vertical, facilitating use of the indicators on the syringe (not shown). It may also further increase the amount of liquid which can be extracted as a bevel of the tip 304' of the cannula 302' can be arranged to face toward the interior side wall of the vial. In such a case the extraction unit holder 30' may be provided with an elastic material to reduce rotational movement of the extraction unit. It may also be proved with a grip or lock element (not shown) for preventing rotation of the extraction unit 300'.

Fig. 13 shows another embodiment of the invention. Unless otherwise stated the reference numbers indicate the same or similar features as shown in the previous figures. In this embodiment the vial holder 20', extraction unit 30' and ventilation unit holder 40' is provided in an attachable holder unit 4', which can be attached to a rack 6' provided on the base unit 2' of the dose extraction aid 1'. The holder 4' has an attachment device 5' for temporally interlocking with a recess 7' provided in the rack 6', thereby attaching the attachable holder unit 4' to the rack 6'. The attachable holder unit 4' is here configured to position the extraction unit 300' and ventilation unit 400' in relation to the vial 200', and when the holder unit 4' is attached to the rack 6', the vial axis will be inclined in relation to the base surface 3'. A holder unit 4' such as the one shown allows an operator to arrange the vial 200', extraction unit 300' and ventilation unit 400' prior to attaching it to the rack 6' as shown in Fig. 13. This may be advantageous in some situation, such as when one operator prepares and another operator extracts doses from the vial using the dose extraction aid T or allowing more freedom in orientation and movement for the operator when preparing. It also allows the holder unit 4' to be a disposable unit, which can be disposed after the vial has been emptied. This eliminates the need for removing the ventilation unit 400' and extraction unit 300' from the dose extraction aid and thus handling of exposed cannula, which improves working conditions for the operator and eases waste handling. The vial holder unit 20' in this embodiment is similar to that of Fig. 7, but without the first and second support surfaces. In this embodiment the neck rest 2T and top element 24' hold the vial 200'. This may require a tight fit of the of the neck, collar and/or cap of the vial in the vial holder 20'. The attachable vial holder 4' may also have first and second support surfaces similar to those of the embodiment in Fig. 7. The extraction unit holder 30' and the ventilation unit holder 40' are here circumferentially closed cylindrical sockets for receiving the hubs 30T and 40T, providing a tight fit. A range of holder units 4' may be provided for different vial types, which holder units 4' are each compatible with the same base unit 2'.

Fig. 14 shows the dose extraction aid T of Fig. 7, wherein the extraction unit 300' and ventilation unit 400' are in the process of being arranged in the holder 4' which is attached to the rack 5'.

Fig. 15 shows a perspective view of another embodiment of the invention which aids the operator in following the extraction process. Unless otherwise stated the reference numbers indicate the same or similar features as shown in the previous figures. The dose extraction aid T in this embodiment also has a camera unit holder 60' attached to the base unit 2'. The camera unit holder 60' is arranged such that a camera unit (not shown) held in the holder 60' can record the liquid level in-side the syringe (not shown). In this embodiment the camera unit holder 60' is configured to receive and hold a mobile telephone which can both record the liquid level in the syringe and display a recorded video on the display of the mobile phone. The camera unit could display the live images from the camera without saving. The camera unit holder 60' is here a clamp 6T having a top clamp element 62' and bottom clamp element 63' which are adjustable with respect to each other such that camera units of different sizes can be held in the camera unit holder 60'. The vial holder 20' is seen to be similar to the vial holder shown in Fig. 7. The extraction unit holder 30' and ventilation unit holder are here hollow, partially open cylinders extending in the extraction axis 30a' and ventilation axis 40a' respectively. The extraction unit 300' and ventilation unit 400' can be introduced into the cylinders, and the internal diameter of the cylinders are such that the flanges 303' and 403' of the hubs 30T and 302' will engage holders 30', 40' to hold the extraction unit 300' and ventilation unit 400' in place. The cylinders are provided with an open section along the extraction axis 30a' and ventilation 40a', allowing the extraction unit 300' and ventilation unit 400' to be removed after use and allows easy cleaning. The dose extraction aid T also has screen 50', which extends in parallel with the extraction axis 30a'. The screen 50' may help a human operator or a camera unit read the liquid level in the syringe arranged in the extraction unit 300', by providing an optimal background colour or pattern. The screen 50' is here provided with a syringe support element 5T for holding the syringe 500', whereby the screen 50' in this embodiment also forms part of the extraction unit holder 30'. In other embodiments, the screen 50' does not support the syringe 500' and do not form part of the extraction unit holder. A shape or pattern, here a square with rounded comers 52', is provided on the screen 50' to indicate the intended liquid level in the syringe when the correct dose volume has been extracted and/or helping a camera unit to focus on the correct section of the syringe. Fig. 16 shows the dose extraction aid of Fig. 15 with a vial 200', extraction unit 300', ventilation unit 400' and syringe 500' arranged therein. A mobile phone 600' is arranged in the camera unit holder 60'. The mobile phone 600' can then display images of the of syringe, allowing the human operator a better view of the liquid level in the syringe, which may help in reducing strain in the eyes of the human operator.

Fig. 17a and 17b shows the dose extraction aid T of Fig. 15 from other angles showing further details of the screen 50' and the camera unit holder 60'. As can be seen the bottom clamp 63' is mounted on the dose extraction aid T by sliding it onto the clamp support 64'. The bottom clamp 63' is provided with a threaded through hole 65' at one side, into which a threaded bolt 66' can be inserted, whereby the threaded bolt 66' can engage the clamp support 64' to lock the vertical position of the bottom clamp 63'. Other means for adjusting the position of the bottom clamp are conceivable, such as a gear rack and gear connection between the bottom clamp and clamp support. The top clamp 62' is provided with prongs 67' for sliding into recesses 68' in the bottom clamp to mount the top clamp 62' to the bottom clamp 63'. In this embodiment the top clamp 62' and bottom clamp 63' are each provided with a tension element 69'. A tensioner e.g. an elastic band (not shown) can be mounted to the tension elements 69', thereby clamping the top clamp 62' and bottom clamp 63' together and whereby the camera unit is held place in the camera unit holder 60'. This allows the camera unit holder 60' to hold camera units of different sizes in place. Other means of achieving the adjustability of the camera unit holder 60' than those shown here is within the knowledge of the skilled person. The camera unit holder 60' could be configured to hold the camera unit at an inclined angle, such that e.g. the display of the mobile phone 600' is arranged at a better viewing angle for the human operator. In such a case a mirror (not shown) could be provided to allow the camera unit to record the syringe substantially perpendicularly to a length axis of the syringe.

Fig. 18 shows a perspective view of another embodiment of the dose extraction aid T. Unless otherwise stated the reference numbers indicate the same or similar features as shown in the previous figures. This embodiment also has a camera unit holder 60', but in this embodiment the camera unit 600' is a bullet type camera, which is connected to an external display unit 610', which displays live or recorded images of the syringe. The camera unit holder 60' is here an arm with a fitting allowing the bullet type camera unit 600' to be mounted therein.

Fig. 19 shows a perspective view of another embodiment of a dose extraction aid T, wherein the extraction unit holder 30' is provided with a grip element 33' for engaging the hub 30T to prevent rotation of the extraction unit 300'. The grip element can be operated by a human operator to lock and release the extraction unit, by moving of the wing elements of the grip element 33'.

Fig. 20 shows a perspective view of another embodiment of a dose extraction aid T, wherein the extraction unit holder 30' holds the syringe 500' to arrange the cannula 302' in the vial 200'. The extraction unit holder has a first 3T and second support element 32' for engaging the syringe 500'. A screen 50' is provided as part of the extraction unit holder 30'. In this embodiment the extraction unit comprises the syringe 500', hub 30T and cannula 302'. Such an extraction unit holder 30' may be advantageous in terms of sterility and/or material requirements as the number of components of the dose extraction aid potentially coming into contact with the cannula is reduced.