JPH0112498B2 - - Google Patents

Description

[Detailed Description of the Invention] I. Background of the Invention (Technical Field) The present invention relates to a medical liquid injection syringe, more specifically, a medical liquid injection syringe for continuously injecting various medical liquids in minute amounts over a long period of time. This invention relates to a drug injection syringe.

(Prior art and its problems) Various pumps have been developed to continuously infuse various drug solutions into patients, etc., but most of them are designed for bedside use, and are small and lightweight pumps that can be carried by patients and used for light work. Pumps have not been sufficiently developed, and many conventional pumps require electrical power sources, are complex, and are expensive.

Under these circumstances, a pump that utilizes osmotic pressure is known as a pump that can be made small and lightweight, and has a simple mechanism. This osmotic pump basically fills one filling chamber formed through a semipermeable membrane with water and the other filling chamber with an aqueous solution of a predetermined concentration, and moves the water to the aqueous solution side based on the osmotic pressure difference. The increase in volume on the aqueous solution side caused by this is transmitted to the compartment filled with the medicinal solution to be administered, and the medicinal solution is continuously poured out from the compartment for a long period of time.

However, when conventional osmotic pumps are used to continuously administer drug solutions into arteries and veins, they are small enough that patients can carry them around for light work.
It has yet to be lightweight and have a simple structure. In addition, conventionally, a flat membrane is used as a semipermeable membrane, and this flat semipermeable membrane also functions as a partition between filling chambers for water and aqueous solutions. Adjustment of the movement speed of all water, that is, adjustment of the drug solution pouring speed, must be adjusted only by the concentration of the aqueous solution, and the degree of freedom in selecting the drug solution pouring speed is small. For this reason, when the size and weight are reduced, the pouring volume cannot be increased sufficiently. Furthermore, no material has been obtained that exhibits good properties that can be put to practical use, such as the stability of the pouring rate or the insensitivity to the load pressure of the chemical liquid pouring port.

In view of these circumstances, the present inventor has previously proposed an osmotic-type dispensing pump using a so-called hollow eye bar as a semipermeable membrane.

In the dispensing pump proposed above, by changing the length, pore diameter, and number of hollow fibers used, it is possible to select a drug solution dispensing speed over a wide range with the same pump size.

However, as long as osmotic pressure is used, two liquids with different concentrations to obtain the osmotic pressure difference and a space to accommodate each liquid are essential, which is a fundamental problem in promoting further compactness and weight reduction. It has become an obstacle.

Purpose of the Invention The present invention was made in view of the above-mentioned circumstances, and is designed to be small and lightweight enough to be carried by a patient for light work when used for continuous administration of drug solutions into arteries and veins. The first object of the present invention is to provide a medical micro-drug injection syringe that has a simple structure.

A second object of the present invention is to provide a medical micro-drug injection syringe that allows a wide range of drug solution injection speeds to be selected and set, regardless of the size of the syringe.

A third object of the present invention is to provide a medical micro-drug injection syringe that exhibits good characteristics in terms of stability in dispensing rate and insensitivity to load pressure for practical use.

A fourth object of the present invention is to provide a medical microdrug injection syringe that can be made disposable.

That is, the present invention is a micro-drug injection syringe used for medical purposes, which includes a driving means on the proximal end side;
A first partition wall is formed in a housing having a medical solution spout at its end, and is slidable liquid-tightly along the inner circumferential wall of the housing at predetermined intervals sequentially from the end side of the housing; A chemical liquid injector including a second partition wall fixed to a peripheral wall, a third partition wall formed to be slidable liquid-tightly along the inner peripheral wall of the housing, and the spout formed by the housing and the first partition wall. a first chamber for liquid filling; a second chamber for liquid filling that is closed by the housing and the first and second partitions; and a second chamber for liquid filling that is closed by the housing and the second and third partitions. A third chamber for filling, and at least one hollow eye bar having micro pores provided between the second chamber and the third chamber, and both chambers are connected to each other through the micro pores of the hollow eye bar. The drive means includes a screw shaft mounted from the base end of the housing toward the inside of the housing, and a screw shaft that is rotatable into the housing and prevented from moving in the axial direction. a nut screwed onto the screw shaft; and a spring installed between the nut and the proximal surface of the second partition wall, The liquid in the third chamber pressurized by the spring force adjusted to the specified value leaks into the second chamber through the hollow eye bar, so that the pressurized liquid in the second chamber moves the first partition into the housing. The medical micro-drug injection syringe is configured such that the medical liquid in the first chamber is continuously discharged from the spout according to the amount of displacement of the first partition wall.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The medical micro-drug injection syringe of the present invention will be described in detail with reference to preferred embodiments shown in the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a preferred example of the medical micro-drug injection syringe of the present invention. Syringe 1 of the present invention
A drug solution spout 3 is provided on the distal side of the cylindrical housing 2.
is formed, and a driving means 4 is provided on the proximal end side. Inside the housing 2, the housing 2 is sequentially spaced apart from the distal end of the housing 2 by an appropriate distance.
a first partition wall 5 that is slidable liquid-tightly along the inner circumferential wall of the partition wall 5;
Similarly to the second partition wall 6 and the first partition wall 5 fixed to the inner peripheral wall of the housing 2, a third partition wall 7 is formed which can slide along the inner peripheral wall of the housing 2 in a liquid-tight manner. As a result, the housing 2 and the first partition wall 5 form a first chamber 8 for filling a medical liquid including a medical liquid spout in the housing 2, a first chamber 8 for filling the medical liquid including a medical liquid spout in the housing 2,
The partition 5 and the fixed second partition 6 form a second chamber for filling a suitable liquid, preferably water, and the housing 2, the fixed second partition 6 and the slidable third
The partition 7 forms a third chamber 10 for filling with a suitable liquid, preferably water.

The first and third partition walls 5 and 7 are connected to the housing 2
It is preferable that the inner circumferential wall of the tube is liquid-tight and slidable with as little resistance as possible, and is preferably constructed of a gasket. The first chamber 8 is filled with a medicinal solution such as insulin that should be continuously injected in small amounts. The second chamber 9 and the third chamber 10 are filled with a liquid for applying pressure to pour out the medicinal solution in the first chamber 8, but water is most preferable from the viewpoint of safety. especially,
It is important to prevent the liquid in the second chamber 9 from mixing into the chemical liquid in the first chamber 8.

The second chamber 9 and the third chamber 10 are configured to be in fluid communication. At least two holes 11 for communication are formed in the fixed partition wall 6, and at least one hollow eye bar 12 having a large number of fine holes as will be described in detail later is stretched between these holes to provide a height for liquid leaching. Use a resistive film. As a result, both chambers 9 and 10 communicate only through the fine holes of the hollow eye bar 12.

As the hollow fiber 12 used for high-resistance fluid communication between the second chamber 9 and the third chamber 10, any fine porous hollow tube may be used, but one made of regenerated cellulose is most preferable. This was revealed as a result of the experiment. Hollow eye bars have a pore diameter of 10 to 20 Å, an inner diameter of 200 μm, and an outer diameter of
It is preferable to use a combination of multiple pieces of 230 μm.

On the other hand, a driving means 4 is provided on the proximal end side of the housing 2. In the present invention, the drive means 4 is provided between a nut 16 screwed onto a screw shaft 15 rotatably mounted in an opening 14 formed in the proximal wall 13 of the housing 2 and a slidable third partition wall 7. It is composed of a compression coil spring 17 provided. This spring 17 is preferably guided by a guide 18 formed on the third partition 7. A rotation knob 19 is provided at the end of the screw shaft 14, and a housing 2 is provided on the screw shaft 14.
A stop 20 is provided inside the proximal wall 13 of the screw shaft 15, and the knob 19 and the stop 20 prevent the screw shaft 15 from wobbling in the axial direction. Note that the amount of rotation of the knob 19, that is, the speed of dispensing the drug solution, can be appropriately controlled by indicating means (not shown), such as a scale, provided in connection with the knob 19.

Specific Effects of the Invention With the first chamber 8 filled with the required chemical solution, and the second chamber 9 and the third chamber 10 filled with the required amount of liquid, the screw shaft 15 is rotated by rotating the knob 19. When rotated, the nut 16 screwed onto the screw shaft 15 moves toward the distal end of the housing 2 and compresses the coil spring 17. The spring pressure caused by this presses the third partition wall 7 and pushes it against the housing 2.
toward the distal end of the tube to pressurize the liquid in the third tube 10. The pressurized liquid in the third chamber 10 is pushed out through the micropores of the hollow eye bar 12, and the pressurized liquid in the third chamber 10 is
leaches within. Then, the liquid in the second chamber 9 is pressurized or the volume increases, and this force presses and moves the first partition wall 5 toward the distal end of the housing 2. The first partition wall is moved according to the amount of movement of the first partition wall.
The medicinal solution in the chamber 8 is poured out through the spout 3 as shown by an arrow 21 and injected into a patient or the like.

If the knob 19 is sequentially rotated by a predetermined amount as necessary, the above-described small amount of medicinal liquid is repeatedly dispensed continuously over a long period of time.

Next, the action of the medical micro-drug injection syringe of the present invention will be explained using a specific example.

Syringe characteristics were measured using a syringe having a structure as shown in FIG. The results are shown in FIG. As the spring, a spring with a small spring constant (k=4.12×10 ^-2 Kg/mm) was used in order to reduce the decrease in spring force caused by the movement of the nut due to the rotation of the screw shaft. As a hollow eye bar, the inner diameter is 200μm,
Eighteen hollow fiber eyelets made of regenerated cellulose having an outer diameter of 230 μm, an average pore diameter of 10 to 20 Å, and a length of 10 cm were used.
The chemical solution pouring end pressure is approximately atmospheric pressure, and the outflow flow rate is 1.
The amount of outflow per minute was measured five times in a row using an electronic balance, and the average value was taken as the average value.

In the second graph, the upper part shows the relationship between the pressure converted from the spring force and the outflow flow rate of the chemical solution.The linearity between the pressure and the outflow flow rate is good, and this relationship is maintained up to about 2 kg/ ^cm2 . It was done. In addition, in the graph in Figure 2, the lower part shows the relationship between pressure and total _outflow when using the above-mentioned hollow eye bar and ^spring . This is the result when the effective area of the partition wall 5 is 3.14 cm ² and up to 5 ml of water flows out. By outflowing to 5 ml, the pressure has decreased by about 25%. Therefore, it can be seen that when this spring is used, the decrease in the outflow flow rate can be suppressed to 8% or less by rewinding the spring and resetting it to P ₀ when 1.7 ml flows out.
Such problems of reduced flow rate and spring rewind can be easily improved by making the spring constant smaller.

FIG. 3 shows the load characteristics of the medical micro-drug injection syringe of the present invention using the pressure in terms of spring force as a parameter. This was obtained for an example using 25 hollow eye bars of 10 cm as described above, and the outflow flow rate shows a decreasing tendency as the load pressure increases, but the theoretical curve (shown by the solid line in the figure)
The difference is within several percent, which is sufficient for practical use.

Specific Effects of the Invention The medical micro-drug injection syringe of the present invention has many advantages over conventional ones, as described below.

(1) The entire syringe can be extremely small and lightweight;
In addition, the structure is simple, and the syringe can be carried around for continuous administration of drug solutions, and light work can be done.

(2) This syringe has a simple structure, so the manufacturing cost is low and it can be made disposable, making it useful from the viewpoint of economy and safety against infection.

(3) Since it does not use an electric power source and has almost no mechanical parts, the psychological burden on patients caused by conventional mechanical noise is eliminated.

(4) Even if air gets mixed into the hollow eye bar due to a malfunction or a damaged part of the drive part, the outflow flow rate will simply decrease or stop, and there is no risk of air getting into the body or backflow of blood.

(5) In the present invention, the communicating holes are hollow fibers, so by selectively changing the length, porosity, inner and outer diameters of the hollow fibers, or the number of hollow fibers used, the liquid injection speed can be arbitrarily changed over a wide range. Can be done.

(6) The chemical solution pouring speed is stable, and the insensitivity to the load pressure at the end of the chemical solution pouring port shows good characteristics that can be used for practical purposes.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional view of the medical micro-drug injection syringe of the present invention, and Fig. 2 shows the relationship between the pressure converted from the spring force and the outflow flow rate of the medicinal solution in the upper part, and the pressure and the total flow rate in the lower part. FIG. 3 is a graph showing the relationship with the outflow amount, and is a graph showing the load characteristics of the medical micro-drug injection syringe of the present invention using pressure in terms of spring force as a parameter. Explanation of symbols 1 1... Medical micro-drug injection syringe of the present invention, 2... Housing, 3... Medicinal solution spout,
4... Driving means, 5, 7... Slidable partition wall, 6... Fixed partition wall, 8... First chamber, 9... Second chamber, 10... Third chamber
Chamber, 11...hole, 12...hollow eye bar, 13...
End wall, 14... Opening, 15... Screw shaft, 16... Nut, 17... Coil spring, 18... Guide, 19... Knob, 20... Stop, 21... Chemical solution pouring direction.

Claims (1)

[Scope of Claims] 1. A medical liquid injection syringe with a small amount of liquid medicine used for medical purposes, which is provided in a housing having a driving means at the proximal end and a liquid medicine spout at the distal end, and which is arranged in order from the distal end of the housing. a first partition wall formed to be slidable in a liquid-tight manner along the inner circumferential wall of the housing with a predetermined distance therebetween; a second partition wall fixed to the inner circumferential wall of the housing; a third partition wall formed to be slidable; a first chamber for dispensing the drug solution including the spout formed by the housing and the first partition wall; the housing and the first and second partition walls; a third chamber for liquid filling that is closed by the housing and the second and third partition walls; and between the second chamber and the third chamber. and a communication hole through which both chambers communicate with each other only through the micropores of the hollow fiber, and the driving means is arranged to extend from the proximal end of the housing. a screw shaft mounted toward the inside of the housing; means for rotatably and immovably mounting the screw shaft in the housing; a nut screwed onto the screw shaft; and the nut. and a spring installed between the surface of the base end side of the second partition, and the liquid in the third chamber pressurized by the spring force adjusted to a predetermined value by rotation of the screw shaft flows into the hollow. By seeping into the second chamber through the fiber, the pressurized liquid in the second chamber displaces the first partition toward a distal side of the housing;
A micro-dose medical liquid injection syringe, characterized in that the medical liquid in the first chamber is continuously discharged from the spout according to the amount of displacement of the first partition.