Patent Application
20100275916
The present invention relates to a medicine ejection apparatus which is constructed so that a user can use it with carrying it, and can be used for an inhalation apparatus for making the user inhale a medicine, and the like, and its control method.
In order to make a medicine which a medicine ejection apparatus, such as an inhaler, ejects arrive at an objective site, an ejection droplet diameter and a user's respiratory behavior become important factors. As for the ejection droplet diameter and respiratory behavior, there are conditions suitable for each according to a site which a medicine is made to arrive at. Thus, in inhalation treatment, its curative effect is dependent on how a user inhales.
In Japanese Publication of PCT International Application No. H10-507096, it is described that inhalation which has a high lung deposition rate and good efficiency can be achieved by ejecting an aerosolized medicine within a range of determined inhalation flow rate and inhalation amount. The inhalation apparatus disclosed in Japanese Publication of PCT International Application No. H10-507096 can be controlled so as to start ejection of a medicine when a user's inhalation flow rate reaches a predetermined value, and to stops the ejection of the medicine when it reaches certain predetermined inhalation amount.
In addition, in Japanese Publication of PCT International Application No. 2006-506151, a technique of registering a user's inhalation pattern and spraying in accordance with the pattern is disclosed as means of making liquid droplets inhaled in a proper inhalation profile. According to this technique, spraying can be synchronized in pulsed manner with breathing by measuring beforehand a user's breathing pattern and recording the information in an inhaler.
On the other hand, an inhalation apparatus has been developed, which makes minute liquid droplets of a medicine ejected in an air current path, through which air inhaled through a mouthpiece flows, using an ejection principle of an ink jet system to make a user inhale them (refer to Japanese Patent Application Laid-Open No. 2004-283245). Such inhalation apparatuses have an advantage of being able to spray a predetermined amount of medicine precisely in an equalized particle diameter.
In the inhalation apparatuses described in the above-mentioned background art, even if inhalation parameters in a spraying start were suitable, an inhalation operation following it might not be appropriate. However, it is not expectable that a user performs the same inhalation operation each time, and when a medicine is released only while a suitable inhalation profile is achieved, there is no guarantee that a whole dose can be administered by one time of inhalation. For example, when a user stops inhalation for a certain reason in the middle of inhalation, a possibility of an ejection amount of medicine not reaching the dose is high.
In this way, in the conventional inhalation apparatuses, it could not be said that quantitative control could be performed since it could not been grasped whether a user inhaled a dose of medicine securely.
An object of the present invention is to provide a medicine ejection apparatus which can medicate a user in a set dose securely regardless of a user's inhalation operation, and its control method, in a medicine ejection apparatus which ejects a medicine according to a user's inhalation behavior.
The present invention is directed to a medicine ejection apparatus which ejects a medicine for medicating a user, characterized by comprising:
a medicine ejecting unit which has an element that generates energy for ejecting the medicine;
a drive control unit which controls a drive start and a drive stop of the element; and
an ejection amount determining unit which determines a total amount of a medicine that is ejected from the medicine ejecting unit after the element performs a drive stop, the drive control unit enabling the element to perform driving so as to eject an amount of medicine calculated from difference between the set ejection amount and the total amount of medicine when the total amount of medicine determined by the ejection amount determining unit does not reach the set ejection amount.
The medicine ejection apparatus can comprise a determining unit which determines a driving condition of the element for performing ejection of the amount of medicine calculated from difference between the set ejection amount and the total amount of the medicine.
The medicine ejection apparatus can comprise a sensor for detecting a user's inhalation, and in that the drive control unit controls a drive start and a drive stop of the element on the basis of an output signal from the sensor.
The medicine ejection apparatus can comprise a display unit in which a result of determining whether total amount of a medicine determined by the ejection amount determining unit reaches into the set ejection amount is displayed.
The element can be an electrothermal transducer which gives heat energy to the medicine.
The ejection amount determining unit can determine ejection amount on the basis of a driving condition of the electrothermal transducer.
The present invention is directed to a control method of a medicine ejection apparatus which ejects a medicine for medicating a user, characterized by comprising:
starting ejection of a medicine;
stopping the ejection of the medicine;
determining a total amount of the medicine which is ejected from the ejection starting of the medicine to the ejection stop;
judging whether the total amount reaches a set ejection amount; and
enabling it to eject an amount of medicine calculated from difference between the set ejection amount and the total amount of the medicine when it is judged that the total amount of the medicine does not reach the set ejection amount.
The control method can comprise determining an ejecting condition for ejecting an amount of medicine calculated from difference between the set ejection amount and the total amount of the medicine.
The medicine ejection apparatus can starts the ejection of the medicine by detecting a user's inhalation and can stop the ejection of the medicine on the basis of the users' subsequent inhalation condition.
According to the medicine ejection apparatus of the present invention, even if an amount of a medicine which is ejected in one time of inhalation does not reach ejection amount set beforehand in the apparatus as one dose, deficient ejection amount can be ejected. For this reason, a user can be made to inhale the set dose.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.
Preferred embodiments of the present invention will now be described in detail in accordance with the accompanying drawings.
In addition, the same reference numerals are assigned to the same components fundamentally, and their descriptions are omitted.
Conceptual construction of a medicine ejection apparatus of the present invention which ejects a medicine for medicating a user is illustrated in
When a user's inhalation is detected by the inhalation detecting sensor 102, an output signal is sent to the CPU 103, drive of the ejection head 107 is started by the drive control unit 103c, and the medicine is ejected. In addition, when it determines by the inhalation detecting sensor 102 that a user's inhalation is ended, or when it is determined that it is not in a suitable inhalation state, the drive of the ejection head 107 is stopped by the drive control unit 103c, and the ejection of the medicine is ended. Here, a total amount of the medicine which is ejected in the period is determined by an ejection amount recognizing unit 105 as an ejection amount determining unit. Then, it is judged whether the total amount of the ejected medicine reaches set ejection amount by the total amount of the medicine determined by the ejection amount recognizing unit 105 being compared with the set ejection amount recorded in memory 103a. When it does not reach the set ejection amount, it is enabled again to drive the ejection head 107 by the drive control unit 103c so as to eject an amount of medicine calculated based on difference from the set ejection amount. Although it is suitable that the calculated amount here is amount itself corresponding to the difference between the set ejection amount and the total amount of the medicine which is ejected, the present invention is not limited to this. For example, in the case of a medicine which does not need control of strict amount, such as steroid, it is also conceivable to administer it somewhat more than the above-mentioned difference. An essence of the present invention is to perform second ejection on the basis of difference between ejection amount in one-time ejection, and ejection amount set beforehand. Even when a dose (set ejection amount) cannot be inhaled by one time of inhalation, an amount of ejection which is the same as or almost the same as the set ejection amount can be performed.
In this way, when performing the second ejection, it can be performed that the driving condition determining unit 103b as a determining unit determines driving conditions of the ejection head 107 for ejecting the amount of medicine calculated based on the difference from the set ejection amount. Then, according to the determined driving conditions, it can be performed to eject the same amount as the set ejection amount by enabling drive of the ejection head 107 by the drive control unit 103c. Even when the ejection amount recognizing unit 105 cannot grasp ejection amount of a medicine in-situ in the midst of ejection, by determining ejection conditions for achieving predetermined ejection amount in advance and performing drive according to the conditions, it can be determined that the ejection of the predetermined amount is completed. In addition, the ejection amount recognizing unit 105 is arranged in the CPU 103 depending on an embodiment.
Here, second and later ejections may be performed automatically or may be performed by a user's switch depression. When performed automatically, it can be performed on the basis of an output signal of the inhalation detecting sensor 102.
A main body of the medicine ejection apparatus can have a display unit 106, such as an LCD display, and it can be performed to display determination result of whether it reaches the set ejection amount, and the like in this display unit 106.
Here, the medicine ejecting unit (ejection head) 107 has two or more ejection openings, and arbitrary ejection energy generating elements provided in relation of one-to-one, one-to-many and many-to-one to an ejection opening. An electrothermal transducer which gives heat energy to a medicine, or an electromechanical transducer which gives mechanical energy can be exemplified. That is, as the ejection methods of a medicine, a method (thermal jet system) of giving heat energy to a medicine and making it ejected using an electrothermal transducer, and a method (piezo jet system) of ejecting a medicine using oscillating pressure of an electromechanical transducer (for example, a piezoelectric element) which gives mechanical energy to the medicine can be exemplified. These systems may be called ink jet systems. The ejection method is selectable according to a type of a medicine, or the like.
When a thermal jet system is used, it can be performed to enhance size accuracy and repeatability of an aperture of an ejection opening, heat amount of a thermal pulse used for ejection, and a micro heater as an electrothermal transducer, in regard to each ejection head. Thus, it can be performed to achieve a narrow droplet diameter distribution. In addition, head manufacturing cost is low and applicability to small apparatuses which need frequent exchange of a head is also high. Hence, when the medicine ejection apparatus is requested to have portability or convenience, in particular, an ejection principle of a thermal jet type can be adopted.
Here, a determination method of the driving conditions for controlling ejection amount of a medicine arbitrarily will be exemplified. First, ejection amount is changeable by changing an ejecting operation period when the medicine is ejected. Here, in this specification, the “ejecting operation period” or “ejection period” means time from giving a first pulse to the ejection energy generating element to finishing giving a last pulse with continuously giving a series of pulses, that is, a series of period while a pulse train for ejection energy generation is supplied. It can be performed to increase medicine ejection amount by making the ejecting operation period longer. In addition, it can be also performed to change ejection amount by changing an ejection frequency of the ejection energy generating element instead of changing the ejecting operation period. Here, the “ejection frequency” is equivalent to the number of pulse signals for ejecting the medicine given to the ejection energy generating element per unit time. This may be called a drive frequency.
In addition, the ejection amount of the medicine for achieving a necessary dosage may be changed by combining these both methods.
As an inhalation detecting sensor used for the present invention, a pressure sensor arranged in an air current path can be exemplified. It can be performed to grasp inhalation conditions, such as a user's inhalation start and subsequent inhalation strength, by the pressure sensor detecting a pressure change (negative pressure fluctuation) generated in the air current path by a user's inhalation. Besides that, a common flow rate sensor which measures a gas flow rate in the air flow path can be used.
Concept of the medicine used for the present invention includes not only a medicine such as a pharmaceutical compound which shows a pharmacological and physiological effect, but also a component for a seductive taste or a seductive smell, a dye, a pigment, and the like in addition to the pharmaceutical compound. Then, it does not matter whether a medicine is liquid or powder.
In addition, the medical fluid used for the present invention means a liquid medicine or a liquid medium including a medicine. Arbitrary additive agents may be included in the medical fluid. Any of dissolution, dispersion, emulsification, suspension, and slurry may be sufficient as a state of the medicine in liquid, and when equalized in liquid, it is better.
When using medical liquid as a medicine, it is suitable that the main medium of the liquid is plain water or an organic solvent, and in consideration of being administered into a living body, it is suitable that plain water is the main medium.
One time of ejecting operation period of the medicine ejection apparatus which is a suitable embodiment of the present invention and has the inhalation detecting sensor 102 depends on a user's inhalation condition. In such a case, in particular, total amount of the medicine which is ejected in one time of ejecting operation period may not reach ejection amount set beforehand as one dose. A control method of the medicine ejection apparatus of the present invention which can eject set ejection amount securely also in such a case although inhalation is divided into multiple times will be specifically described below.
Patterns considered as relation between the medicine ejection period and the user's inhalation are illustrated in
Even when ejection is performed according to the determined driving conditions at the time of second inhalation, since ejection is performed only within the proper range described above, it is conceivable that it may not reach the set ejection amount even in the second inhalation. In that case, total amount of the medicine which is ejected again is calculated, and amount resulting from adding the total amount of the medicine which was ejected at the time of the first inhalation, and the set ejection amount are compared. Then, driving conditions are determined again so as to eject the amount of medicine corresponding to difference from the set ejection amount. This operation is repeated until the total amount of the medicine which is ejected reaches the set ejection amount.
Although a suitable inhalation rate range is approximately 0.1 to 1.0 L/s and so for an adult, it may change with individual difference, illness, conditions, and the like.
As respiratory parameters used for the inhalation conditions which determines the ejection period, besides the above-mentioned inhalation rate, inhalation amount may be used. The “inhalation rate” means speed of an air current generated in an air current path, and it is calculated on the basis of speed of air which passes a given point in an inhalation detection unit. The “inhalation amount” is amount of inhaled air which is calculated by time integration of inhalation rate data.
Suitable inhalation conditions differ according to a medicine to be used. According to a site of a respiratory organ in which a medicine is made to act, a suitable droplet diameter, a particle size distribution, and inhalation conditions which are suitable for them are set.
If a medicine to be inhaled is a bronchodilator, it is better not to arrive at a palmonary alveolus since a site to be made to act is a bronchus. Although optimum conditions also depend on a user's physical and physiological features, it turns out that generally it is better to make liquid droplets have some particle size distribution, and not to increase inhalation flow rate and inhalation amount.
In addition, in the case of whole body dosing like insulin, it is better to avoid deposition in a bronchus, and to make liquid droplets arrive at a palmonary alveolus. Also at this time, although optimum conditions also depend on a user's physical and physiological features, it turns out that generally it is better to make a diameter of a liquid droplet be 1 to 5 μm, make a particle size distribution sharp, make an inhalation rate small, and increase inhalation amount.
Setting of an inhalation condition is set so that an ejection flag (FLG) may become ON when an inhalation rate is within a certain range. Furthermore, it is also good to find inhalation amount from time integration of an inhalation rate and to add a rate with a user's maximum inspiratory capacity (IC), which was measured beforehand, to the condition. By adding the inhalation amount on the condition, it can be performed to deliver a spraying medicine to lungs before the lungs are filled with air to be inhaled.
It is desirable that the setting of actual inhalation conditions is determined on the basis of a medicine used and an analysis of a user's respiratory profile. Data of a general pulmonary function test is used for the analysis of a respiratory profile, and the inhalation conditions are set. Such inhalation condition data may be recorded on a recording medium inside a main body, or a user may store it as external memory.
An example of a control method of the medicine ejection apparatus of the present invention is illustrated in a flowchart in
It is determined during ejection whether or not the ejection amount Vt of the medicine by the time has reached the set ejection amount VT (S004). A method of performing this determination will be exemplified below.
First, the ejection amount Vt can be determined in-situ by the ejection amount recognizing unit 105. In this case, whether the set ejection amount VT is reached can be determined directly. Next, since the ejection conditions for ejecting the set ejection amount VT are determined, it may be determined by whether or not ejection on the ejection conditions has been completed.
When Vt reaches VT by this determination, the ejection is ended (S006). During the ejection, it is also continuously monitored whether the inhalation conditions fall in the predetermined range on the basis of the output signal of the inhalation detecting sensor 102 (S005). When the inhalation conditions fall in the predetermined range, the ejection is continued succeedingly. When the inhalation conditions become out of the predetermined range, the ejection is ended even if it has not reached VT (S006). When the ejection is ended, error determination is performed (S007). Here, not only determination of whether the ejection amount has reached VT but determination of, for example, whether temperature and resistance of a minute heater as the ejection energy generating element indicate unusual values and the ejection has been not normally performed are performed. When there is no error, a power source is turned OFF as what the predetermined amount of ejection has been completed, and the operation is ended. When there is an error, it shifts to S008. When there is an error except the error on the ejection amount (N), its contents are shown on a display block 106, and a user is warned of them (S009). In the case of an error on the ejection amount, the residual dose Vr (=VT−Vt) is shown, and second inhalation is prompted to a user. In addition, the ejection conditions at the time of ejecting the Vr are calculated according to necessity by the driving condition determining unit 103b (S010). A counter of the ejection amount Vt is reset to zero, and the set ejection amount VT in the second ejection is made into the residual ejection amount Vr. Error detection is reset (S011). The above-mentioned flow is repeated hereafter until the set ejection amount is ejected completely.
As means for determining ejection amount used for the present invention, it can be calculated from the number of given pulses (hereafter, this is called an ejection shot number) and a droplet diameter when an ejection principle of an ink jet is used for a medicine ejecting unit. Since being dependent on a diameter of an ejection opening (nozzle), a droplet diameter can be grasped as a constant beforehand and an ejection shot number can be calculated from ejection conditions. In this calculation method, even if ejection is performed with an ejection condition being changed during one time of inhalation, its ejection amount can be grasped accurately.
In addition, when volume of the medicine tank 108 changes according to amount of an inside medicine, the amount which is ejected can be also grasped by detecting the volume change. As for the volume change, a method of detecting a displacement of a movable wall, which constructs a part of the medicine tank 108, by a distance sensor such as an optical type, or an ultrasonic type, can be mentioned. In addition, since a liquid amount supplied to the ejection head 107 can be measured by installing a liquid flow rate sensor between the ejection head 107 and the medicine tank 108, ejection amount can be also grasped from this value.
Furthermore, in the case where the medicine tank 108 is an airtight container isolated from the open air besides an ejection opening of the ejection head 107 and it is not necessary to change volume of the medicine tank during ejection, ejection amount can be also grasped by measuring a pressure change occurring in the medicine tank corresponding to ejection amount. For example, a pressure sensor which measures internal pressure of the medicine tank can be used.
These ejection amount recognizing units may be used independently, or may be used in combination.
A perspective view of the cartridge 101 into which the ejection head unit 107 and medicine tank 108 are integrated is illustrated in
The ejection head unit 107 is mainly constructed of a housing 39, and the ejection head 8 is a thermal ink jet type ejection head publicly known in a p printer field. There is a frame 24, to which the cap 21 contacts at the time of protection and which is made of rubber, in the periphery of the ejection opening surface of the ejection head 8. An electrical connection member (contact pin) for supplying electric power for making a heater provided in the ejection head 8 generate heat energy from a power source provided in the main body is arranged on a not-illustrated surface of the housing 39.
In the above construction, a method by calculation from the number of ejected liquid droplets can be used as means of determining and grasping ejection amount. Formula 1 is an operational expression of ejection amount on the basis of digital ejection by an ink jet system.
V
t
=V
1
×n×f×t×A (Formula 1)
Vt: Amount ejected after t seconds
V1: Volume of one liquid droplet
n: Number of nozzles
f: Ejection frequency
t: Ejection drive time
A: Correction Value
Here, the correction value A is a coefficient which corrects volume by liquid droplets called satellites except main liquid droplets ejected from one nozzle when one drive pulse is applied. In an ink jet system, since an ejected droplet diameter is dependent on a diameter of a nozzle, a particle diameter of a main liquid droplet is constant. In addition, it can be performed to measure amount ejected in t seconds accurately by recording values of V1 and A beforehand since ejection of the satellites also is constant depending on ejection conditions. It is considered that the ejection of the satellites is affected by, for example, pulse width and a drive voltage. “Pulse width” here is application time in one pulse signal application. In addition, a “drive voltage” is a voltage given to an ejection energy generating element. Since the nozzle number n is a number of holes ejecting a medicine, a number used for ejection is applied to Formula 1. The nozzle number to be used is changeable by ejection conditions.
Relation between the ejecting operation period and the ejection amount is illustrated in a graph in
V
t=4/3·Π·(2.8)3×2000 (pieces)×10 (kHz)×t (seconds)×1.15 (1)
This well coincided with the result in
Relation between the ejection frequency and the ejection amount is illustrated in a graph in
V
t=4/3·Π·(2.8)3×2000 (pieces)×f (kHz)×1.0 (second)×1.15 (2)
This well coincided with the result in
In this way, when the ejection principle of an ink jet system is used, ejection total amount in a predetermined ejection period can be calculated from the ejection conditions. If residual ejection amount Vr is calculated, the ejection conditions of second time of ejection are determined, but when not changing the conditions, such as an ejection frequency, the driving condition determining unit 103b determines so as to shorten the ejection period than that in the first time of ejection. In this way, when this embodiment is adopted, it is necessary to determine the ejection conditions in the second time of ejection.
When a range of a suitable inhalation rate is 0.1 to 1.0 L/s and detection is performed with a pressure sensor in an air current path portion in a sectional area of 10 mm2, the above-mentioned suitable range is detectable as −0.12 to −6 kPa.
Next, an embodiment of a method of determining ejection amount from an internal pressure change of a medicine tank will be described. Although outline of a main body of an inhalation apparatus is the same as that in the first example, in this embodiment, it has construction that the medicine cartridge 101 can measure pressure in the medicine tank 108. Sectional views of the medicine cartridge 101 in this embodiment are illustrated in
Inside the ejection head unit 107, there is the hollow needle 38, the medical fluid pass 42 is provided so as to be connected to this, and a medical fluid is supplied to the ejection head 8. The medical fluid pass 42 branches in a direction of a pressure detection opening 23 on the way. A pressure sensor provided in an inhalation apparatus body side is connected to the pressure detection opening 23. In the pressure detection opening 23, a sealant (O-ring) 22 for preventing a pressure leak at the time of the pressure sensor connection after main body attachment is arranged.
Pressure in a tank is transmitted from a branched small hole to the pressure detection opening 23 through a space in an upper portion. The upper portion (a surface dividing the pressure detection opening 23 and this space) of this space becomes a membrane which is constructed from a flexible material, and detects a tank internal pressure from a displacement of the membrane by a pressure change by the pressure sensor in the main body side.
The other main construction of the medicine cartridge 101 is the same as that of the first example.
Experimental result of investigating relation between the pressure and the ejection amount in the medicine tank 108 is illustrated in a graph in
Hence, so long as the above-mentioned relation between the tank internal pressures and the ejection amount is beforehand stored in the inhalation apparatus body, the ejection amount can be determined.
Sectional views of the medicine cartridge 101 according to the third embodiment of the present invention are illustrated in
Since an iron core 45 is fixed to the movable rubber stopper 34 and a magnet 46 provided at a tip of a plunger 47 attracts mutually with the iron core 45 with a magnetic force, the plunger 47 and movable rubber stopper 34 are fixed. According to the ejection of the medical fluid, the movable rubber stopper 34 is moved by the plunger 47.
A position sensor 49 is oppositely provided to the movable rubber stopper 34, and a detection plate 48 is provided in a part of the magnets 46. The ejection amount can be measured accurately by reading the movement amount of the movable rubber stopper 34 using the position sensor 49.
Hence, so long as the relation between the movement amount of the rubber stopper and the ejection amount is beforehand stored in the inhalation apparatus body, the ejection amount can be determined.
The medicine ejection apparatus of the present invention may be used for various uses besides for medicine inhalation. For example, it can be also used for a spray form ejecting apparatus of aromatics, an inhalation apparatus of luxury goods, such as nicotine, and the like. Thus, the medicine ejection apparatus of the present invention is applicable to various uses which need certain and sanitary ejection.
The present invention is not limited to the above embodiments and various changes and modifications can be made within the spirit and scope of the present invention. Therefore to apprise the public of the scope of the present invention, the following claims are made.
This application claims the benefit of Japanese Patent Applications No. 2008-014458, filed Jan. 25, 2008, and No. 2008-103554, filed Apr. 11, 2008, which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-014458 | Jan 2008 | JP | national |
| 2008-103554 | Apr 2008 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2009/051515 | 1/23/2009 | WO | 00 | 9/24/2009 |
