Liquid Dispenser

Abstract

Method and apparatus for dispensing a precise amount of liquid from a sealed container into a syringe, open at one end, without engaging the syringe plunger. A positive and negative pressure is successively applied to the liquid in the sealed container forcing it through a conduit into the syringe. The predetermined position of the conduit in the syringe determines the level of the liquid in the syringe.

Description

THE INVENTION

This invention relates to a method and apparatus for dispensing liquids. More particularly, the invention relates to a method and apparatus for dispensing a precise volume of liquid into a syringe without engaging the syringe plunger and without first attaching a needle.

The present trend in the distribution of drugs on the hospital level is to prepare and administer such drugs as a unit dose or a single unit. Unit-dose drug distribution is a system of packaging drugs in individual doses containing a predetermined amount of the drug ready for direct administration to the patient. The drugs packaged may include solid and liquid orals, injectables and topicals; they may be prepared in the single-unit form either by the drug manufacturer or by the hospital pharmacist. Under this system, the pharmacist sends the exact or maximum useable quantity of properly labeled drugs needed for a period of time (usually two to four times per 24 hour period). Each medication unit is clearly identified and sealed from the time of preparation by the pharmacist until the time of administration at the patient's bedside.

In the past, the hospital pharmacy would supply drugs in large volume to the floor in a hospital where the drugs were used in quantity. The nurse or person in charge of administering drugs on that floor would draw medication when needed from the large supply reservoir and would return the reservoir to a shelf or drug storage area on that floor. This multiple-dose procedure has led, however, to numerous errors either in administering the correct quantity of medication since the drugs might be prepared by a large number of persons working on the floor whose work load requires them to spend less time in preparing medication. In order to minimize errors and to increase overall efficiency, many hospitals are transferring to the new unit-dose method of handling drugs.

Applicants' invention relates to a method and apparatus to implement unit-dose packaging of liquid injectable drugs into a syringe. Prior to this invention, syringes were filled to the desired volume by inserting the needle of the syringe into a vial containing the liquid and depressing and withdrawing the plunger in the syringe to draw the liquid from the vial into the syringe. If too much liquid was drawn into the syringe, it was ejected into a waste receptacle by depressing the plunger. This method of packaging did not lend itself to the unit-dose system since the now unsterile needle must be transferred from the hospital pharmacy to the patient and then be reused on the patient in an unsterile state or after it has been cleaned with alcohol and cotton.

Applicants' invention minimizes the risk of contaminating the syringe during filling and transportation by providing a method and apparatus for dispensing a known volume of liquid into a syringe through the "tip end" of the syringe without engaging the plunger and without first attaching a needle to the syringe.

The other advantages of unit-dose system for injectables over the previously used multiple-dose system is that the new system decreases the probability of medication error both in the quality and quantity of the drug administered; it decreases the risk of pilferage since it places drug control with the hospital pharmacist rather that the nursing unit; it provides for complete identification of the drug, lot number, expiration date, etc., from the time the drug leaves the hospital pharmacy up to the time of administration to the patient. It can be seen that this system places in the hands of the pharmacist the responsibility of drug preparation, thereby relieving the nurse of one of the three stages of medication distribution.

SUMMARY OF THE INVENTION

With these advantages of the unit-dose system over the multiple-dose system, it is the object of this invention to provide a method and apparatus for dispensing a known volume of fluid into a syringe without engaging the plunger and without first attaching a needle to the syringe.

It is another object of this invention to provide a method and apparatus to dispense liquid into a syringe which is adaptable to the unit-dose method of packaging.

It is an object of this invention to provide a method and apparatus to dispense a known volume of liquid into syringes of various volume capacities.

It is also an object of this invention to provide a method and apparatus to dispense liquid into a syringe adaptable to the unit-dose packaging process which decreases the risk of contamination over the present method of dispensing using plunger movement.

In order to implement these objectives, this invention provides a method and apparatus for dispensing liquid into a needless syringe by supporting the syringe in an inverted position with the tip end extending upwardly and the plunger end extending downwardly; inserting into the barrel of the syringe a liquid conduit means, filling the syringe with liquid, withdrawing excess liquid from the barrel of the syringe through the conduit means until the desired volume fluid remains in the syringe.

The accompanying drawings illustrate the preferred embodiment of the syringe filling apparatus of this invention.

IN THE DRAWINGS:

FIG. 1 is a perspective drawing of the dispensing apparatus which is the subject of this invention.

FIG. 2 is a partial perspective sectional view of the dispensing apparatus shown in FIG. 1 taken along line 2--2' wherein the syringe is in a raised position.

FIG. 3 is a partial perspective sectional view of the dispensing apparatus similar to that of FIG. 2, wherein the syringe is in a lowered position.

DESCRIPTION OF THE APPARATUS

Referring now to FIG. 1, there is provided a dispensing apparatus generally designated by the numeral 10. The dispensing apparatus 10, which may also be referred to as a ringstand, includes a flat base 11 and a support rod 12 extending perpendicularly from the base. Since it is desirable that the apparatus be easily cleaned, it is preferred that it be made of a non-corroding metal such as stainless steel or aluminum, or be chromium plated.

Support rod 12 is provided with a plurality of support clamps 23 and 33 which serve the function of holding vial 20 which is a sealed container in an inverted position. Bottle hold down clamp 33 is slideably mounted on rod 12 and is held at the desired height by mount 32, which is also slideably attached to rod 12. Clamp 33 is free to rotate about rod 12 within slot 17 of mount 32.

Support clamp 23 is slideably mounted onto rod 12 and is characterized by two pairs of bifurcated support members 27 and 28. Within the lower support member 28 is provided a threaded thumb screw 18.

As shown in FIG. 1, support clamps 23 and 33 coact to securely hold a vial 20, placed therebetween, in a secure inverted position. Vial 20 is of the type commonly used to store liquid injectables. As shown in FIG. 2, vial 20 contains a metal closure 22, open at the center thereof with a resilient liner 26 (FIG. 2) covering the center of the metal overcap, thereby permitting the perforation of the liner with a needle without removing the closure. In this invention, vial 20 may be considered a multi-dose package from which liquids are drawn to fill many unit-dose packages.

A long air supply needle 25 is inserted through liner 26, shown in FIG. 2, and extended into the inverted vial 20 until the tip of the needle is above the level of liquid in the inverted vial. It will become obvious from the remaining description that the tip of supply needle 25 should always raise above the liquid in the inverted vial. Hollow flexible tube 16 communicates between resilient bulb 15 shown in FIG. 1 and air supply needle 25. Bulb 15 is supported above vial 20 by means of bulb support clamp 43 which, like clamps 23 and 33, is slideably mounted to support rod 12. Although FIG. 1 shows a bulb 15 as supplying air to vial 20, it should be understood that any means may be provided supplying the necessary positive and negative pressure upon the liquid in the vial.

As shown in FIGS. 1 and 2, located below clamp 23 and slideably mounted to support rod 12 is another clamp 13. This clamp has located therein a vertical opening 41 used to guide a syringe 40 open at one end and placed therein into alignment with conduit 35. Syringe support clamp 13 has also located therein opening 37 to align that clamp with calibrated scale 30. Opening 37 is of a larger diameter than scale 30 so that clamp 13 may be vertically moved with respect to clamp 23.

Scale or indicia means 30 is a rod with a flat surface at its lower end containing calibrations 31 thereon. The scale is inserted into vial support clamp 23 and securely held in position in said clamp by set screw 21. Scale 30 is so positioned into clamp 23 that it is substantially parallel to rod 12. Thus, when knob 36 of clamp 13 is rotated, clamp 13 is free to move in a vertical direction to align with any of the calibrations 31 on the scale.

Dispensing conduit 35 is securely clamped into a vertical position within bifurcated support member 28 by means of thumb screw 18. Conduit 35 consists of two needles extending axially in opposite directions. One needle is inserted into vial 20 through resilient liner 26 so that it just pierces the liner and does not extend appreciably beyond the liner; the other needle is inserted into the tip end 44 of syringe 40 which syringe is held in position by guide clamp 13.

OPERATION OF THE FILLING APPARATUS

The remaining description relates to the calibration and operation of the dispensing apparatus 10 and shows how this invention lends itself to the unit-dose method of drug distribution.

Although the calibration of the instrument shall be described below, it is assumed for purposes of explaining the method of operation that the apparatus has been properly calibrated for the particular syringe being filled.

FIGS. 2 and 3 show syringe support clamp 13 in the extreme upper and lower positions respectively with respect to calibrations 31. It should be understood that clamp 13 may be adjusted to any position by means of knob 36 so as to align with the desired calibrations 31 on scale 30. The calibrations indicate the volume of liquid which will be dispensed into the syringe 40 by compressing and releasing resilient plunger 15, shown in FIG. 1.

Referring to FIGS. 1 and 2, in the operation of the apparatus, clamp 13 is adjusted by means of knob 36 so that the top plane 14 of clamp 13 aligns with the desired scale reading on the calibrations 31. This represents the volume of liquid to be dispensed into the syringe. Then, a graduated syringe 40, having graduations directly related to the calibrations 31 of scale 30, is inserted tip end first through the opening 41 of guide clamp 13. While the syringe is being inserted in clamp 13, the lower end of conduit 35 is inserted into the tip end 44 of the syringe. When the flange 46 of the syringe comes to rest against the bottom plane of clamp 13, it is secured in place during the filling operation by the operator who merely holds his finger against the flange.

After the syringe 40 is in the filling position about conduit 35 and clamp 13 has been aligned with the desired volume calibration 31 on scale 30, the operator depresses bulb 15, shown in FIG. 1. Air is forced through tube 16 and through air supply needle 25, causing a positive pressure upon the surface of the liquid in vial 20. This pressure forces the liquid from the vial through the upper and lower needles of conduit 35 and into syringe 40. If the liquid level in the syringe rises above the lowermost tip of conduit 35, that liquid is drawn back into vial 20 when bulb 15 is released. This is caused by the negative pressure in the bulb being transmitted through tube 16 and air supply needle 25 to the surface of the liquid in the vial. If the uppermost end of needle 25 is below the level of the liquid in the vial, it can be seen that, upon release of bulb 15, the liquid in the vial will be drawn through needle 25, through line 16, and into bulb 15.

This drawback problem can be eliminated if the end of needle 25 is always positioned above the level of the liquid in inverted vial 20. The vacuum or negative pressure on the surface of the liquid in vial 20 caused by the release of bulb 15 draws back into vial 20 the liquid from syringe 40, which is above the terminal end of conduit 35. When the liquid level in the syringe corresponds to lowermost point of the conduit, no more liquid is drawn back into vial 20. Rather, the vacuum above the liquid level in the vial and in bulb 15 is released by the air which is drawn through tip end 44 and then through conduit 35. The liquid level in the syringe should now coincide with the terminal end of conduit 35. Since the operation of this dispensing apparatus always causes the terminal end of conduit 35 to correspond to the level of liquid in the syringe 40, the volume calibrations 31 can be easily placed on scale 30 as hereinafter described.

CALIBRATION OF THE DISPENSING APPARATUS

It must first be pointed out in the description of the method of calibrating this dispensing apparatus that the calibrations 31 are made to coincide with the linear volume calibrations on the wall of the particular syringe to be filled. If different syringes 40 are used of varying internal diameters and volumes, it is obvious that the linear scale on the wall of one syringe may not correspond to the linear scale on the wall of another syringe of a different internal diameter. Therefore, the calibrations 31 must be changed each time a syringe is used which does not have the same internal diameter, volume, or plunger location as does the calibrating syringe.

For purposes of illustration, it is assumed that the syringes of one manufacturer coincide with those of another so that the same calibrations 31 may be used for all syringes. It is also assumed in order to make this calibration that all syringes come with some prepackaged plunger 47 or other means to hold liquid in the syringe, which plunger is located at the same constant position with respect to the uniform graduations on the wall of the syringe. It is preferable for purposes of calibration and dispensing that the prepackaged plunger 47 always be located at the largest number calibration on the syringe, which, in the preferred embodiment, is number 2 1/2.

Referring now to FIG. 3, conduit 35 is securely clamped into the lower bifarcated member 28 or clamp 23 by means of thumb screw 18 so that the tip of the uppermost needle of conduit 35 just perforates liner 26.

A syringe 40, containing uniform volume graduations beginning with the number 0 and containing a plunger 47 pre-positioned at the largest volume calibration on the syringe is inserted into support clamp 13 until the flange 46 of the syringe 40 contacts the bottom plane of the clamp 13. The syringe is held in place against the clamp 13 by one finger of the operator. The clamp 13 and syringe 40 are adjusted by releasing knob 36 until the plane corresponding to the 0 graduation on the wall of the syringe coincides with the terminal end of conduit 35 as shown in FIG. 3. The point on scale 30 which is horizontally aligned with the top plane 14 of clamp 13 is scored with the number which corresponds to the largest number on the graduation of the wall of the syringe, which in this instance is the number 2 1/2. This represents a volume of 2 1/2 cc.

The clamp 13 and the syringe 40 are then raised as shown in FIG. 2 by releasing knob 36 until the terminal end of conduit 35 coincides with the largest number graduation on the wall of the syringe, which in the preferred embodiment is 2 1/2 . The point on scale 30, which is horizontally aligned with the top plane 14 of clamp 13, is scored with the number 0. This represents a volume of 0 cc. When the needle is at the maximum number graduation on the wall of the syringe, it is desirable that the plunger 47 be pre-aligned with this graduation and that the needle contact the plunger. If the plunger is not so aligned, a corrective factor equal to the volume between the plunger and the largest number graduation must be added to the volume indicated on the calibration scale 31.

After two lines have been scored on scale 30 representing the minimum and maximum volume which can be accommodated by the syringe, the remainder of the space between these two lines is equally divided into the desired number of major and minor graduations corresponding to the number of major and minor graduations on the wall of the syringe.

When scale 30 has been calibrated for one syringe of a given internal diameter and volume, it can be used for any other syringe of the same internal diameter and volume provided that the flange 46 and the plunger 47 are in the same position within the syringe as the syringe used for calibration.

It can be seen from this description of the method of calibration that any commercial syringe can be used for unit-dose dispensing if the dispensing apparatus has been calibrated for that particular syringe as described above.

It can also be seen that the above-described syringe dispenser can be easily adapted to the unit-dose distribution system, since a pharmacist can fill a large number of syringes having the same capacity, diameter, and plunger position to any desired volume level in a short period of time by merely inserting the syringe into the guide clamp, adjusting the guide to align with the desired volume on the scale and depressing the bulb to force liquid both into and out of the supply vial. A needle containing a protective cover can be positioned over the tip end of the syringe immediately after dispensing by this method. The syringe is now ready to be used in the unit-dose distribution system.

This dispensing apparatus permits a large number of the same syringes to be filled to a known volume without moving the plunger and without first attaching a needle to the syringe, thereby promoting efficiency and safety in the filling of syringes.

Claims

We claim:

1. Apparatus for controllably dispensing a precise amount of liquid from a sealed container to an open-topped container, comprising:

means for supporting said sealed container,

means connected to said sealed container for alternately establishing a negative and positive pressure within the container,

conduit means extending from the interior of said sealed container to a preselected point in the interior of said open-topped container and having its outside terminal portion extending in a downwardly direction,

guide means connected to said support means for guiding and aligning the open-topped container telescopingly over the terminal end of said conduit, and,

means connected to said guide means for adjusting the vertical position thereof.

2. The apparatus as claimed in claim 1 wherein said pressure establishing means extends into the sealed container and above the level of liquid in the container to establish a positive and negative pressure upon the surface of the liquid in the container.

3. The apparatus claimed in claim 1 wherein said conduit means extends to a point within said sealed container which point is below the liquid level in the sealed container.

4. The apparatus as claimed in claim 1 wherein the preselected point in the interior of the open-topped container corresponds to the desired level of liquid to be dispensed into said open-topped container.

5. The apparatus as claimed in claim 1 including indicia means adjacent to said guide means for indicating the volume of liquid to be dispensed into said open-topped container.

6. Method for controllably dispensing a precise amount of liquid from a sealed container to an open-ended container through a conduit means, comprising the steps of:

supporting said sealed container,

positioning said open-ended container in an upright position,

positioning said conduit means between the interior of said sealed container and the interior of said open-ended container so that the outside terminal portion of said conduit means extends in a downwardly direction within said open-ended container,

guiding and aligning said open-topped container telescopically over the terminal end of said conduit means so that the terminal end of said conduit means coincides with a predetermined point in the interior of the open-ended container corresponding to a preselected volume encompassed by the container volume below said point, and

alternately applying a positive and negative pressure within the sealed container to deliver an excess of the desired amount of liquid through said conduit and into said open-ended containers and to withdraw the excess.

7. Method for controllably dispensing a precise amount of liquid from a sealed container to an open-ended container through a conduit means, comprising the steps of:

supporting said sealed container,

positioning said open-ended container in an upright position,

positioning said conduit means between the interior of said sealed container and the interior of said open-ended container so that the outside terminal portion of said conduit means extends in a downwardly direction within said open-ended container,

adjusting the relative position of said open-ended container and the terminal end of said conduit means telescoped therein so that the terminal end of said conduit means coincides with a predetermined point in the interior of said container, and

applying a positive pressure within the sealed container to force a quantity of liquid through said conduit and into said open-ended containers to a depth greater than the position of the terminal portion of said conduit, and then applying a negative pressure within the sealed container to return that quantity of liquid from the open-ended container that is above the terminal portion of the conduit.