JPH05221468A - Control release system - Google Patents

Abstract

PURPOSE:To discharge a proper quantity of functional substances such as medicine, pesticides, fertilizer and perfume at any time by a method wherein a functional substance storing chamber is provided with a shape memory alloy extensible by a rise in temperature and a spring and the functional substance is discharged therefrom by the extension of the shape memory alloy. CONSTITUTION:A switch 2 is turned on to energize a shape memory alloy 1 and, when the shape memory alloy 1 is heated to its transition temperature so as to be extended, a storing chamber 4 filled with the functional substance 3 is moved to the right. When an opening 5 formed in the storing chamber 4 is shifted to match with an opening 7 formed in an exterior wall 6, the functional substance 3 is discharged through these openings to the outside. When the switch 2 is turned off to deenergize the shape memory alloy 1, the shape memory alloy 1 is contracted and the storing chamber 4 is returned to its original position by the restoring force of a spring 8 to stop the discharge of the functional substance. This permits the functional substance to be discharged in a necessary quantity at a desired time.

Description

Detailed Description of the Invention

[0001]

[Industrial field of application] In recent years, in order to release substances, such as medicines, agricultural chemicals, fragrances, cosmetics, fertilizers, and other substances that act on the environment and exert some function, to the environment by releasing the required amount in an appropriate ratio when necessary. The control release technology has been attracting attention, and for example, a drug is called a drug delivery system (DDS), and research and development are being actively conducted. The present invention is intended to provide a new system for controlling and releasing various functional substances for such a purpose.

[0002]

2. Description of the Related Art Conventionally, research and development in the field of drug delivery systems (DDS) for the purpose of controlled release of medicines have been very active, but recently, control into new fields such as pesticides, fertilizers and cosmetics has been carried out. There is an increasing momentum to apply and expand the technology of the release. Most of these conventional control release technologies make a composite of a functional substance and a polymeric material by laminating the functional substance between polymer films or mixing and dispersing it in a polymer gel. Most things. Control of the release duration, which is the purpose of control release, is performed by appropriately selecting the polymer material and controlling the diffusion rate of the functional substance in the polymer. Alternatively, the structure of the complex of the functional substance and the polymer is made porous to increase the internal surface area to accelerate the release or, conversely, by adding a filler which becomes a diffusion barrier in the complex. The release is also suppressed. However, in the products made by the conventional technique, the release of the functional substance itself occurs automatically and continues until the functional substance is continuously released, and the release is performed when and when needed. It was not equipped with a possible ON-OFF control mechanism.

[0003]

As described above, in the conventional control release system, the emission is turned on and off.
Since it does not have a control mechanism and does not release the required amount when the release is really necessary, it cannot be said to be an efficient release method. Moreover, since the release is sustained even when it is not needed, it was often harmful. Future control release systems are required to have an ON-OFF switching mechanism that releases only when the environment requires it.

[0004]

In order to solve the above-mentioned problems, some kind of ON-OFF switching mechanism must be added to the control release system of the functional substance. In the present invention, the shape memory alloy 1 is used. The system shown in FIGS. 1 and 2 is provided with an ON-OFF switching mechanism for releasing the functional substance 3. That is, when the system as shown in FIGS. 1 and 2 is energized via the switch 2, the shape memory alloy 1 is heated to its transition temperature and is elongated. Due to this extension movement, the storage chamber 4 for the functional substance 3 moves toward the opposite side (right side), and the opening 5 of the storage chamber 4 moves to the outer wall 6 of the body.
The functional substance 3 is discharged from the storage chamber 4 to the outside because the functional substance 3 is aligned with the opening 7 of the. Next, when the power supply is cut off, the shape memory alloy 1 is cooled and contracts, and the restoring force of the spring 8 attached to the opposite side of the storage chamber 4 causes the storage chamber 4 to move in the opposite direction (leftward). The opening 5 is closed and the release of the functional substance 3 is stopped. 6A is an outside room. Due to the realization of such a structure and mechanism, the release of the functional substance 3 is also turned on by turning the electrical stimulation (signal) on and off.
-It became possible to change it to OFF. Since the release of the functional substance 3 is generally required in response to changes in environmental conditions, the purpose is to connect a sensor that monitors the environmental conditions to a release control system and intermittently release the response in response to an electric signal from the sensor. It can be widely applied and used as a system suitable for.

The contents of this description will be further described below. As the shape memory alloy 1 that can be used in the present invention, Ti-Ni, Ni-Al, Cu-Zn-Al, Ag
-Cd, Au-Cd, Cu-Ni-Al, Cu-Au-Zn, Cu-Zn, In-Tl, In-Cd, Ti-N
i-Cu, Ti-Ni-Fe, and all other alloys that exhibit a shape memory phenomenon are included, and their compositional relationship should be selected and used in a wide range of suitable compositions so that various transition temperatures can be selected as needed. You can The functional substance 3 in the present invention is used in a wide range of fields such as life, industry, etc. from the viewpoint of a wide range of functions such as chemical, medical, biological, optical, electrical, electronic, etc., and has a certain function. It is a general term for substances that can exert effects. Specific examples include medicines, agricultural chemicals, hormones, pheromones, fertilizers, growth promoters, fragrances, dyes, surfactants, catalysts, reaction regulators, cosmetics, etc., but are not limited thereto. . In the present invention, these functional substances 3 are shown in FIG.
It is intended to fill the storage chamber 4 shown in FIG. 2 and intermittently release it from the opening 5 in response to an electrical input signal. Any material can be used to form the housed outer chamber 6A, and ceramics, metals, polymers (plastics), etc. can be used, and the size thereof can be widely selected according to the intended use. is there. Examples will be shown below.

[0006]

EXAMPLES Example 1 Lead wires were attached to both ends of a spring made of a Ti—Ni-based shape memory alloy, and this was attached to a wall of a substance storage chamber as shown in FIGS. An electric circuit was constructed by embedding it in the wall of the main body surrounded from the outside. A spring spring made of steel was embedded in the other wall of the substance storage chamber, and one of the springs was fixed to the wall of the main body. A battery and ON-OFF switching were introduced into the electric circuit sandwiching the shape memory alloy spring, and 7 g of testosterone was added to the substance storage chamber. When the ON-OFF switch was operated and the system was energized, the Ni-T was released after about 2 minutes.
The i-spring extended about 2.5 cm, and the testosterone reservoir also moved about the same distance to the other side. As a result, it was confirmed that the opening at the bottom of the storage chamber overlaps with the opening at the outer wall of the main body to release testosterone inside. Next, when the energization was stopped, the Ni-Ti spring contracted by about 2.2 cm, and therefore the storage chamber moved again in the opposite direction to stop the release of testosterone. The release behavior of such testosterone is 0
It occurs repeatedly in response to N-OFF operation, and when energized,
It was observed that the release was initiated and interrupted during a power failure.

(Example 2) Lead wires were connected to both ends of a spring made of Ti-Ni-Fe-based shape memory alloy, and both ends were formed into a functional substance storage chamber wall and a main body outer wall in the same manner as in Example 1. An electric circuit was constructed by fixing and further connecting the lead wire connected to the shape memory alloy spring on the outside of the main body to the battery and the ON-OFF switch. An ordinary steel spring was fixed to the other wall of the functional substance storage chamber, and one of the springs was fixed to the outer wall of the main body. 5 cc of buffer solution containing 100 mg of insulin dissolved in the functional substance storage room
When the system was filled with electricity and the system was energized (5V, 20mA), the Ti-Ni-Fe alloy stretched by 2.8cm after about 1 minute, and the insulin storage room also moved. As a result, the storage room opening and the body opening overlap. As a result, the release of the aqueous insulin solution was confirmed. Next, when the energization was stopped, the shape memory alloy contracted by 2.7 cm, the storage chamber moved to its original position, its opening was blocked, and the release of insulin was stopped. This kind of behavior can be done by turning the system on and off.
It was found that the reproducibility was repeated well even if it was repeated 0 times or more.

[0008]

EFFECTS OF THE INVENTION By adopting a shape memory alloy that expands when heated, it is possible to release the functional substance in the storage chamber when needed and in the required amount.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a control release system of the present invention, showing a non-energized state.

FIG. 2 is also an explanatory view of the control release system of the present invention, showing a release state of the functional substance under an energized state.

[Explanation of symbols]

 1 Shape Memory Alloy 3 Functional Material 4 Storage Room 5 Opening 6 Outer Wall Body 6A Outer Room 7 Opening 8 Spring Spring

Claims (1)

[Claims] 1. A shape memory alloy, a spring, and a storage chamber for a functional substance and an outer chamber which expand when heated.
An electric current responsive control release system that releases a functional substance by the elongation of a shape memory alloy