A METHOD AND A DEVICE FOR ESTIMATING AN AMOUNT OF A POWDER SHAPED MATERIAL PASSING A BEND IN A FLOW CHANNEL

Abstract

The present invention provides a method for estimating an amount of a powder shaped material passing a bend in a flow channel, such as how much drug from an inhaler reaches the lungs of a person. The estimation is based on both the flow rate of the inhalation as well as the rate of release of the drug into the flow channel, where the rate or release itself depends on the flow.

Claims

1-9. (canceled)

10. A method for estimating an amount of a powder shaped material passing a bend in a throat of a person, the method comprising the steps of: providing a closed, container comprising a predetermined quantity of the powder-shaped material, opening the container, wherein the method further comprises the steps of: sensing a flow of a gas, caused by an inhalation of the person, through a flow channel comprising the throat, at least part of the gas flow being provided through the opened container, the at least part of the gas flow through the container releasing, during a first time interval, the predetermined quantity of the material into the gas flow in the flow channel, receiving, during the first time interval, information relating to the gas flow, and calculating, for a number of points of time during the first time interval: a rate of release of the material into the flow channel and an amount of the released material having passed the bend.

11. The method of claim 10, wherein the step of determining the rate of release of the material into the flow channel comprises basing the determination of the rate of release on the actual flow of the gas in the flow channel.

12. The method of claim 10, wherein the calculation of the amount of the released material having passed the bend is based on a comparison of the actual flow in the channel to a first flow interval.

13. The method of claim 10, wherein the calculated amount of material having passed the bend is determined on the basis of the determined rate of release.

14. The method of claim 10, wherein the calculation is terminated when a predetermined amount of the material has been released into the flow channel.

15. The method of claim 10, wherein the closed container is non-pressurized.

16. The method of claim 10, wherein the container is a blister pack.

17. A device for estimating an amount of a powder shaped material passing a bend in a throat of a person, the device comprising: a closed, container comprising a predetermined quantity of the material, the container being capable of being opened, a sensor for determining a flow of a gas through a flow channel comprising the throat of the person, opening means capable of opening the container, wherein the opening means are capable of opening the container so that an inner space of the container comes into fluid connection with the flow channel to enable releasing, during a first time interval, the predetermined quantity of the material into the gas flow in the flow channel, the device further comprising calculating means for calculating, for a number of points of time during the first time interval: a rate of release of the material into the flow channel and an amount of the released material having passed the bend.

18. The device of claim 17, comprising at least a portion of the flow channel, wherein the container may be opened so that an inner space of the container forms part of the flow channel.

19. the device of claim 17, wherein the closed container is non-pressurized.

20. the device of claim 17, wherein the container is a blister pack.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0120] Embodiments of the invention will now be further described with reference to the drawings, in which:

[0121] FIG. 1 illustrates an example of a material, such as a drug, being transported through a bent flow channel, such as the throat of a person,

[0122] FIG. 2 illustrates examples of (inhalation) flow rates over time and further a preferred flow interval,

[0123] FIG. 3 illustrates an embodiment of a delivery device as depicted in FIG. 1, and

[0124] FIG. 4 illustrates powder emission at different flow velocities.

DETAILED DESCRIPTION OF THE DRAWINGS

[0125] In general the present invention relates to a method for determining the amount of a powder-shaped material, such as a drug, inhaled by a person and intended to negotiate the bend in the throat of the person.

[0126] The invention thus may be used for determining the amount of drug reaching the lungs so as to adapt the dose of the dispenser/container, or it may be used for training the person to optimize the inhalation to ensure that as much as possible of the drug reaches the lungs.

[0127] FIG. 1 illustrates a patient 101 and a delivery device 102 configured to deliver a drug to the lungs of the patient 101 via inhalation.

[0128] The device 102 is for inhalation, so that the person 101 engages the inhaler with her/his mouth and inhales through the device 102. The inhaled gas/air enters the mouth and, via the bent throat, the lungs.

[0129] It is known that if the inhalation flow is too low (Vlow), a too large portion of the drug entrained in the air will impact the surfaces 103 of the mouth and thus not reach the throat or the lungs. If, on the other hand, the inhalation flow is too strong (Vhigh), the drug may not be re-directed in the throat but will impact on the back side 104 of the throat and again not reach the lungs. Thus, a preferred inhalation flow interval exists (Vopt) at which the drug is bent in the throat and remains entrained in the air flow until it reaches the lungs.

[0130] Clearly, the preferred inhalation flow interval may depend on the dimensions of the powder as well as the shape and dimensions of the flow channel, including the throat. Thus, for different drugs and/or persons (such as gender and age), different flow intervals may be determined. Often, this correlation is used for identifying a suitable drug and dispenser type for the individual person.

[0131] Yet another factor, however, is that the quantity of drug is usually limited. Thus, an unsuitable flow will cause drug to be lost. This cannot be re-gained by prolonging the inhalation at the desired flow.

[0132] FIG. 2 illustrates three examples of inhalation as a function of time. As previously addressed, an optimal flow rate could ensure a maximum amount of the drug reaching the lungs.

[0133] In this example, a preferred flow interval is illustrated by upper and lower boundaries, 201, 203, respectively. In this example, the flow may be the flow velocity of the gas and thus the drug.

[0134] A first inhalation 202 is illustrated where the flow increases linearly. The fat X 202′ illustrates the point in time where all of the drug has been entrained in the air during the inhalation.

[0135] Clearly, most of the time of the inhalation 202 takes place at a too low flow. Thus, a lot of the drug is lost in the mouth of the person. Only for a short period of time is the flow within the interval so that the drug inhaled at this flow actually reaches the lungs.

[0136] The second inhalation 204, on the other hand, starts out rather forcefully, so that the flow swiftly increases to become too high. Actually, before the flow is reduced to be within the desired interval, the drug dose is depleted (the fat X 204′), so that only very little drug actually reaches the lungs, even if the flow hereafter stays within the interval for a prolonged period of time.

[0137] The third inhalation 206 is more suitable, as the inhalation rather quickly rises to a flow within the interval but stays within the interval until depletion 206′. Clearly, some drug is lost until the flow has increased sufficiently, but the overall amount of drug reaching the lungs of the person in inhalation 206 is much higher than in the other inhalations.

[0138] Determination of the amount of drug reaching the lungs thus should take into account the flow over time. Also, the rate of release of the drug, i.e. how much drug is actually entrained in the air, is relevant, as this describes how much drug is presently transported at that flow—and thus how much drug has a too low, too high or suitable velocity on its way to or through the bend.

[0139] Clearly, if not all drug is entrained in the air at the same time, this may be taken into account by the rate of release.

[0140] Thus, the calculation may be performed in individual steps each based on actual values of the flow and the rate of release. Then, variations in the flow may be taken into account in the determination of the actual amount of drug reaching the lungs. Then, the total amount of drug reaching the lungs (and/or the total amount of drug lost on the way) may be determined by summing these values.

[0141] Yet another factor to take into account is the rate of release, which will depend on the type of drug dispensing used.

[0142] For powder dispensers, the powder may be provided in single dose blisters or the like which are not under pressure and from which the drug is dispensed by allowing the air to flow through the container and thus mix the air and the drug and in that manner transport the drug out of the container.

[0143] Clearly, the rate of release depends on the flow of the gas.

[0144] Allowing the gas to flow through a powder capsule will cause the powder to be entrained in the gas and thus be transported out of the capsule. However, if the gas flow is very low, no or only a little powder may be entrained in the gas, whereas for high gas flows, much more powder will be entrained. Thus, the rate of release (the amount of drug per unit time exiting the capsule) will increase with the flow rate—not only due to more gas flowing out of the capsule per unit time but also due to the concentration in the capsule of entrained drug is higher.

[0145] This is illustrated in FIG. 4 illustrating powder 30 in a drug container 304 where the flow through the container is illustrated by arrows. In the left illustration, the flow through the container is very low, so that the flow in the container is so low that only little powder is entrained in the air. Thus, very little powder, if any, is ejected from the container. In the right illustration, the flow is higher, so that the powder in the container is well entrained in the air and thus ejected from the container with the air.

[0146] Thus, the rate of release may also be determined in the calculation.

[0147] Clearly, the desired flow interval as well as the rate of release may depend on both parameters of the drug container or delivery system/mechanism as well as of the drug itself (powder size/size distribution/surface/weight and the like) as well as of the flow. These parameters may be determined empirically or numerically.

[0148] FIG. 3 illustrates the internal components of the delivery device 102 indicated on FIG. 1. The delivery device may comprise a plurality of internal components such as one or more sensors including a flow sensor 301, a data processor 302, a drug dispenser 303, a drug container 304, an actuator 305 and a display 306. In addition, a flow channel 307 is illustrated as well as a mouth piece 308 for the operator to engage during inhalation through the flow channel 307. The flow sensor is positioned so as to determine the flow in the flow channel 307.

[0149] The flow sensor 301 may be embodied in a number of manners, such as a rotating element or a pressure sensor may be used to measure the flow during the inhalation time. A variety of additional sensors may be employed such as a temperature sensor, humidity sensor and a strain gauge. A temperature sensor and a humidity sensor may be used to take the environmental factors into account, e.g. calculating the percentage of drug that is lost to the environment or remains in the delivery device 102. A strain gauge may be used to measure the available drug in the drug container 304, especially if this is not a single-use container.

[0150] The data processor 302 may be configured to compute the flow rate at a given time instant based on signals provided by the sensor 301. The data processor may also compute a drug dose delivered to the lungs of the patient 101.

[0151] All air flow in the flow channel 307 may flow through the container 304, or only a part thereof, where other portions of the flow may flow around the container 304.

[0152] The processor 302 may receive information relating to the predetermined quantity of the actual drug as well as the desired flow interval and potentially also the rate of release, such as as a function of time and/or flow rate.

[0153] Then, the processor 302 may determine, during or after an inhalation, the total amount of drug reaching the person's lungs from the detected flow and the knowledge relating to the desired flow interval as well as the delivery rate, optionally determined on the basis of the flow and/or time.

[0154] This total amount may be output on the display 306. Alternatively, other information may be output such as the flow over time, information of whether the actual or present flow is sufficient, too low or too high, information relating to whether the dose is depleted or how much dose is still available, or the like. Naturally, this information may also be stored in the dispenser and fed to a database for a professional or advisor to review and give advice to the operator.

[0155] An actuator 305 may be included. This actuator may be used for operating the dispenser to dispense the dose of the drug, such as rupturing a powder blister. The actuator may additionally or optionally be used for awakening the processor so that the calculation can start. The actuator may be operable by the user by e.g. depressing a button or the like or by the air flow in the channel. The flow sensor may be constantly active and may act to activate the processor and/or dispenser, when the flow reaches a desired level.

[0156] Naturally, the device of FIG. 3 may be altered from being a dispenser to a training device. Thus, the container and the dispenser may be dispensed with. Then, the output of the flow sensor is fed to the processor which then from a storage, which may be provided in the processor, derives information relating to the desired flow interval as well as the rate of delivery, especially if this also depends on the flow rate.

[0157] On the basis of this, the processor may again determine how much drug, if it had been dispensed as assumed into the flow channel, would actually reach the uses lungs. Thus, the device is a trainer which may be set to a particular drug, dispenser type or the like (which defines the flow interval and rate of release) so that a user may learn how to inhale in order to, when inhaling through the real inhaler, have as much drug as possible reach the lungs.