JPS62240038A - Medical capsule and its use - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a medical force cell that inhales and collects substances such as body fluids within a living body, or releases medicinal fluids and the like within a living body.

[Prior art]

Various microorganisms live in the bodies of animals, especially in the gastrointestinal tract, and these help the host survive by digesting food and defending against infection by pathogenic microorganisms, but they can also cause cancer, uremia, liver damage, etc. Some produce causative substances. However, these microbiological investigations and research are lagging behind, and in order to promote this research, it is especially important to collect samples (body fluids) at precise locations within the animal's digestive tract while maintaining the surrounding environment. There is a need for tools and methods that can collect or administer drugs.

Under these circumstances, a medical capsule large enough to be administered orally was developed, and a method of collecting a sample or administering medication at an appropriate location in the gastrointestinal tract and later collecting the capsule after it was expelled from the anus. was devised.

As such medical capsules, for example, Japanese Patent Application Laid-open No. 5
As in Publication No. 2-128675, a spring built into a capsule is fixed with a thread, and a signal from outside the body is received at a predetermined position in the body where a sample is taken or medication is administered, and a filament is activated using a built-in battery. There are those that operate the spring by heating and burning out the thread, those that electrically move the spring by command radio waves as in JP-A-52-94682, and JP-A-52-131,678. There are some, such as those that utilize membranes that are digested at a specific pH.

In recent years, shape memory alloys have been attracting attention as they have a shape memory effect that conventional metals do not have, and are being applied in various fields. Those operated by heating from body temperature, such as JP-A-56-1164
No. 45, JP-A-58-19231, JP-A-Sho 5
As in Publication No. 8-121938, etc., a receiving tuning circuit consisting of a receiving coil and a capacitor built into a capsule,
It is applied in the form of a device that sends a radio wave with a tuned (resonant) frequency from outside the body to activate a switching part, and then flows a current from a built-in battery directly to a part of a heater or a shape memory alloy coil to generate heat. There is. In addition, Japanese Patent Application Laid-open No. 58-130031 and Japanese Patent Application Laid-Open No. 58-13580
A method of heating using Joule heat caused by eddy currents generated by high frequency waves (variable magnetic field) has also been proposed, as in Publication No. 8.

However, the method of incorporating a battery into a capsule is not desirable when considering in-vivo use because it involves risks such as liquid leakage and explosion, and also tends to increase the size. On the other hand, methods using membranes that dissolve at a specific pH or shape memory alloys that are activated by body temperature have the disadvantage that they cannot necessarily be activated in appropriate locations.

・Furthermore, the method of heating metal by induction heating using high frequency waves is a well-known method and is widely used for induction hardening and the like. However, in order to heat a shape memory alloy that is large enough to be inserted into a capsule that can be administered orally from outside the body by irradiating high frequency waves from outside the body, the shape memory alloy coil must be extremely small. Because high frequencies are attenuated by moisture and difficult to reach deep inside, a high-frequency transmitter is required in a huge container, and using it as a medical capsule poses problems in terms of patient safety and equipment cost. was there.

(Object of the invention) In view of these problems of medical capsules, the present invention has been made to solve the following problems:
As a result of research aimed at improving the heating efficiency of capsules using shape memory alloys using high-frequency waves, it was possible to quickly heat and operate the shape memory alloy coils inside the capsules using a heating method that applies the principle of a resonant circuit. After discovering this and conducting further investigations, they were able to complete a medical capsule that does not have a power source such as a battery or an electronic circuit, and a method for its use.

[Structure of the invention]

That is, the present invention provides an outer cylindrical container having an opening for inhaling or releasing a substance in a living body, a piston movably disposed within the outer cylindrical container, and a piston located within the outer cylindrical container with one end connected to the piston. A medical capsule characterized by comprising a shape memory alloy coil connected and the other end fixed to the bottom of an outer cylindrical container, and a capacitor forming a resonant circuit with the shape memory alloy coil, further comprising: The capsule is orally administered, and when the capsule reaches a predetermined position in the living body, irradiating a high frequency wave at the resonant frequency of a resonant circuit built into the capsule from outside the living body to generate a resonant current in the circuit, This is a method of using a medical capsule characterized by heating a shape memory alloy coil by generating heat using the resonant current, driving a piston with its shape recovery force, and inhaling or releasing a substance in a living body.

The outer cylindrical container of the capsule used in the present invention has an opening for inhaling, collecting, or releasing a substance,
Further, it is desirable that the opening has a valve for preventing backflow. In other words, when the purpose is inhalation or collection, the material can flow in smoothly with little pressure loss when inflowing from the outside, and after the collection is completed, the collected material can come into contact with and circulate with the external environment of the capsule. If the body has a one-way valve that can completely shut off the water, the sampled substance will not be lost, and body fluids can be sampled in the same environment as in the living body. This is an important function especially for research on anaerobic bacteria. The capsule of the present invention must be of a size that allows for oral administration, the piston must move smoothly while maintaining airtightness, and it must be manufactured with good dimensional accuracy.
In addition, the material must be able to sufficiently withstand acids such as gastric juice, but there are no particular limitations as long as the material is such a material.

The piston that moves inside the capsule is required to be made of a material that is in complete contact with the inner surface of the outer cylindrical container of the capsule and that can move smoothly with little frictional resistance. Therefore, it is desirable to use silicone resin, fluororesin, fluororubber, nitrile rubber, chloroprene rubber, ABS resin, etc., which have good moldability, have a certain degree of elasticity, and have a smooth surface.

In order to move the screws 1 to 1, one end of a coiled wire made of shape memory alloy is connected to the piston, and the other end is fixed to the bottom of the outer cylindrical container. This shape memory alloy coil needs to have an AS point (austenite transformation start temperature) of 37°C or higher in order to be used in vivo, and considering the possibility of heat generation, the AS point is 40°C.
The above is desirable. Furthermore, it is preferable that the Ar point (austenite transformation end temperature) be close to the As point because it is desirable to recover the shape as quickly as possible after the start of heating.

By doing so, when the capsule reaches a predetermined position in the body, the coil can quickly recover its shape and the substance can be inhaled, collected, or released. To produce a shape memory alloy coil, first, a work-hardened shape memory alloy wire is formed into a contracted coil. After heat-treating the coil, it can be stretched at room temperature (martensitic state) and incorporated into a capsule to create a capsule for collecting samples such as body fluids.Conversely, the coil can be heat-treated with the coil stretched, and then the coil can be shrunk at room temperature to create a capsule. If incorporated into the capsule, it can be used to release substances contained within the capsule, such as for drug administration.

In the present invention, in order to quickly heat this shape memory alloy coil by irradiating high frequency waves from outside the living body, the first
As shown in the figure, the simplest LG resonance circuit was constructed by using a shape memory alloy coil (1) as an inductance and connecting a capacitor (2) to it. If this circuit is irradiated with a high frequency wave of a specific frequency, it is possible to generate a resonant current in the circuit that is several tens to hundreds of times larger than an eddy current caused by mere high frequency induction. With this current,
This mechanism generates heat in the shape memory alloy coil (1) to cause shape recovery. Therefore, since no power source or electronic device is built into the capsule, a very small and safe medical capsule can be obtained.

The shape memory alloy coil (1) and the capacitor (2) forming the resonant circuit are not particularly limited;
A small ceramic or tantalum dip capacitor or a chip type capacitor is preferable as a capacitor that can be installed inside the capsule. In addition, the conductive wire connecting these must be sufficiently flexible so that it can follow the movement of the shape memory alloy coil (1).
Enameled wire with a diameter of about φ, vinyl coated wire with a diameter of less than 1 closed, 5
A copper foil ribbon or the like, which is made by cutting a copper foil with a thickness of about 0 μm to a width of about 1 fM1, is good.

Finally, the medical capsule of the present invention is completed by fixing the shape-memory alloy coil as the capsule-constituting parts and fitting the bottom of the capsule, which is equipped with a valve that can perform exhaust or suction according to the movement of the piston. do. This valve at the bottom of the capsule, for example, in the case of a collection capsule, is a valve that prevents the chamber containing the shape memory alloy coil from becoming under positive pressure as the piston moves for collection. , is an exhaust valve that exhausts the air inside the capsule according to the movement of screws 1 to 1.

The frequency f of the high frequency irradiated to the medical capsule of the present invention is determined by the inductance L of the shape memory alloy coil (1) and the capacitance C of the capacitor (2).
) can be obtained using the formula.

A high frequency is preferable in terms of the strength of coupling, the dimensions of the capacitor, the Q value of the resonant circuit, etc., but a low frequency is preferable in terms of attenuation in the body and not heating the body itself. is better. Considering these points. It is preferably in the range of 0.1 to 6 MHz, more preferably 0.5 to 4 MHz. Therefore, the resonant frequency f determined by equation (1) according to the value of inductance L of the shape memory alloy coil (1)
It is sufficient to select and use a capacitor (2) having a capacitance C within the above range.

There are no particular restrictions on the high-frequency heating device used in the present invention, but the inductance L varies slightly depending on the shape of the shape memory alloy coil (1), and the capacitance C of the capacitor (2) also varies individually. The resonant frequency f is not determined theoretically by equation (1), and if the Q value of the circuit is high, even a slight frequency shift will reduce the efficiency, so it is necessary to use a variable capacitor and dip meter to adjust the frequency. It is desirable to have a function to check the resonance frequency.

Further, it is more desirable if the coil has a function of automatically adjusting the frequency in accordance with shape recovery of the shape memory alloy coil. That is, the variable capacitor of the high-frequency heating device is motor-driven to automatically change the resonance frequency corresponding to the change in inductance due to expansion and contraction of the shape memory alloy coil. According to this method, even if there is a frequency shift, heating can always be achieved at the resonant frequency by performing several scans (continuously changing the frequency). Roughly speaking, the purpose of this method can be completely achieved if the driver is driven to follow the frequency while measuring the common frequency. One specific example is to detect that power is absorbed and the oscillation intensity decreases when the frequency matches the resonant frequency of the resonant circuit inside the capsule,
One method is to perform feedback control of the variable capacitor based on this information.

〔Effect of the invention〕

With the present invention, medical capsules that conventionally had to have built-in power sources, electronic circuits, etc., can now be used by simply incorporating a shape-memory alloy coil and a small capacitor that also serve as drive springs and inductances, thereby eliminating high-frequency power from the outside. We have created a completely new type of medical capsule that can be powered and used with energy. The medical capsule of the present invention has no risk of battery leakage or explosion, is small in size, is inexpensive, and is useful not only for research on intestinal bacteria but also for various diagnostics.
It can also be applied to medical treatment, and in the future, it is expected that new treatment methods will be developed that do not involve surgery and are less painful for patients than endoscopic treatment. It is extremely useful.

〔Example〕

An example in which the medical capsule of the present invention is applied to collect intestinal bacteria will be specifically described with reference to FIG.

The outer cylindrical container (3) of the capsule is a polycarbonate cylinder with an outer diameter of 8 m, an inner diameter of 6 m, and a length of 25 mm, and has a silicone rubber truncated cone-shaped glue valve (4) at the tip with an opening.
Attachment 82 is attached. This leaf valve (4) is pushed open by the substance (intestinal fluid containing Ill bacteria) that enters the capsule during collection, that is, suction, but when the internal pressure increases and the substance inside the capsule tries to flow out. for,
They close together perfectly to prevent this.

The piston (5) is made of fluororesin, and the leaf valve side is concave enough to fit the leaf valve (4), and the opposite side has a small hole through which the end of the shape memory alloy coil (6) is fixed. It has a slightly convex shape.

In addition, in order to reduce frictional resistance, the side surface (outer peripheral surface in contact with the inner surface of the outer cylindrical container (4)) is made smaller in diameter at the center than the inner diameter of the outer cylindrical container (4).Capsule outer cylindrical container ( 4) The clearance dimension between the inner surface and the piston surface is 5/
1000 to 10/1000 rrwn, and silicone grease was applied to the contact surface.

The shape memory alloy coil (6) was made by forming a NiTi alloy wire with an AS point of 40° C. and an Af point of 45° C. into a maximum shrinkage of 4 φ and 7 turns, and then heat-treated.

On the other hand, the bottom part (7) of the capsule is a disc with a convex central part, which has a small hole for fixing the shape memory alloy coil (6), a pedestal for installing the capacitor (9), and an exhaust valve (8). It has a capacitance of 3.3 xlO
' After soldering a flexible conductor (10) to the ceramic chip content 1 (9) of the PI, a capacitor (9) was fixed to the pedestal at the bottom of the capsule (7) with adhesive. Next, the shape memory alloy coil (6) is connected to the screws 1 to 1 (5) and the capsule bottom (7), and the conducting wire (10) connected to the content 1 hole (9) is connected to the shape memory alloy coil (6). ) was connected to the end with conductive adhesive. Finally, conductor wire (10) and shape memory alloy coil (6)
After drying, the shape memory alloy coil (6) is stretched to a length where the piston (5) is located at the tip of the outer cylindrical container (3) of the capsule.
This was inserted into the outer cylinder container (3) of the capsule, and the bottom part (7) of the capsule was fitted and set.

This was orally administered to animals and observed under X-ray fluoroscopy. When the capsule reached the colon, 2.8 to 3.2 M
A medical capsule located about 15 cm away was activated by irradiating HZ variable frequency radio waves, and then the capsule was expelled from the anus and the gastrointestinal fluid could be collected. The DC input to the high frequency oscillator at this time was approximately 3KW.

[Brief explanation of drawings]

FIG. 1 is a resonant circuit diagram according to the present invention, and FIG. 2 is a configuration diagram of a medical capsule according to an embodiment of the present invention. Patent applicant Sumitomo Bakelite 1 ~ Co., Ltd.
High School Figure 1 Cause 2

Claims (4)

[Claims] (1) An outer cylindrical container having an opening for inhaling or releasing a substance in a living body, a piston movably disposed within the outer cylindrical container, and a piston located within the outer cylindrical container with one end connected to the piston. A medical capsule comprising a shape memory alloy coil having the other end fixed to the bottom of an outer cylindrical container, and a capacitor forming a resonant circuit with the shape memory alloy coil. (2) The medical capsule according to claim 1, wherein the resonant frequency of the resonant circuit composed of the shape memory alloy coil and the capacitor is in the range of 0.1 to 6 MHz. (3) An outer cylindrical container having an opening for inhaling or releasing a substance in a living body, a piston movably disposed within the outer cylindrical container, and a piston located within the outer cylindrical container with one end connected to the piston. A capsule consisting of a shape memory alloy coil whose other end is fixed to the bottom of an outer cylindrical container, and a capacitor that forms a resonant circuit with the shape memory alloy coil is orally administered, and the capsule reaches a predetermined position in the body. At that time, a high-frequency wave of the resonant frequency of the resonant circuit built in the capsule is irradiated from outside the living body to generate a resonant current in the circuit, and the resonant current causes the shape memory alloy coil to generate heat and heat it. A method of using a medical capsule characterized by driving a piston with shape recovery force to inhale or release a substance in a living body. (4) Detecting the change in the resonant frequency of the resonant circuit as the shape memory alloy coil recovers its shape, and irradiating high frequency while controlling the oscillation frequency of the high frequency to follow the change in the resonant frequency. Claim 3, characterized by:
How to use the medical capsules described in section.