US3435944A - Packing of hypodermic needle assembly - Google Patents

Description

A rilzl, 1969 'lcHl'Ro ISHII 3,435,944v PACKING OFHYPODERMIC NEEDLE ASSEMBLY Filed July 10. 1967 E MEU M I INVENTQR. E

United States Patent US. Cl. 206-43 2 Claims ABSTRACT OF THE DISCLOSURE A packing for a hypodermic needle assembly comprising a covering of synthetic resin film having a dome portion to hold a hypodermic needle assembly, a base plate which consists of a paper sheet fastened to the covering so as to seal the dome portion and a synthetic resin film having a large number of micropores and attached to the surface of the paper sheet.

Background of the invention This invention relates to a packing of hypodermic needle assembly to hold the needle under a sterile condition, more particularly to an improved packing of such needle assembly which permits easy sterilization of the interior thereof and also enables a highly sterilized condition to be maintained until said packing is opened.

The packing including a hypodermic needle assembly under a sterile condition generally consists of a base plate made of paper and a synthetic resin film having a dome portion formed in the central part attached to said base plate in order to hold said needle assembly, such packing is commonly known as blister packing. The needle assembly held in the dome usually comprises a shield such as a plastic sheath in order to protect the cannula portion of the assembly. This shield also serves the purpose of preventing the cannula from being touched by the hand when a needle assembly is fitted to the syringe after being taken out of the packing.

Such packing is completed when sterilization is carried out by introducing sterilizing gases such as ethylene oxide into the interior after mounting a needle assembly therein. The paper constituting a base plate allows the sterilizing gas to permeate therethrough at the time of sterilization and acts as a filter to prevent bacteria from being introduced into the interior after sterilization. However, such a filtering action can occur only when the paper is in a dried condition. When the paper becomes wet by absorbing moisture, bacteria present therein will easily permeate into the interior of the packing along with the moisture attached to the interstices between the paper fibers, thus considerably degrading the sterile condition of the needle assembly contained therein. Furthermore, wetting will reduce the mechanical strength of paper, thus the packing will be damaged during handling.

Summary of the invention This invention provides a packing for a hypodermic needle assembly which has a synthetic resin film having a large number of micropores disposed on the surface of the base plate. The synthetic resin film has a considerably better water repellency than paper, so that the film effectively prevents moisture from penetrating into the paper when the packing is exposed to the moisture, and yet allows sterilizing gases to get into the packing through said numerous micropores bored in the film at the time of sterilizing treatment.

It is therefore one object of this invention to provide a novel packing for a hypodermic needle assembly which has good permeability to sterilizing gases at the time of sterilizing the packing and also prevents bacteria from getting into the interior even when the packing comes in contact with moisture.

Another object of this invention is to provide a packing assembly, the base plate of which is protected from damage even when the packing is wetted.

Brief description of the drawing FIG. 1 is a perspective view of a packing according to this invention; and

FIG. 2 is an enlarged sectional view of the packing taken along the line II-II in FIG. 1.

Description 0 the preferred embodiment Referring now to the accompanying drawing, a packing of hypodermic needle assembly according to this invention illustrated in FIGS. 1 and 2 comprises a base plate 4 consisting of a paper sheet 1 and a synthetic resin film 3 attached to one surface of said paper sheet and having a large number of micropores 2, a transparent covering 8 consisting of high mechanical strength. such as polycarbonate resin fastened to the paper sheet 1 of said base plate by a heat sealed synthetic resin film 7 such as polyethylene, and a hypodermic needle assembly 9 enclosed in said dome portion 5 of said covering 8.

The covering 8 should have sufiicient mechanical strength such as tension or bending strength, polycarbonate resin is Very suitable for this purpose. Where a material of low heat seal properties such as polycarbonate is used in covering 8, it is preferable to insert a thermoplastic material such as polyethylene between said covering and paper sheet 1 in order to supplement the heat seal adhesivity therebetween. However, polyethylene film can be omitted in case a material of good heat seal properties is used for covering 8, or in case adhesion between covering 8 and paper sheet 1 is performed by means of application of adhesive material.

It is necessary that the paper sheet 1 permits gases to permeate through the interstices between the fibers, and prevents bacteria from passing therethrough. Permeability of bacteria through the paper sheet depends upon the compactness of fibers and the thickness of the paper sheet. Kraft paper which is known to have a compact and uniform structure is preferable for this purpose, Where such paper sheet has a thickness of about 100 microns, it will be sufficiently protected that bacteria permeates the paper sheet by its filter effect.

To one surface of the paper sheet is attached the syn thetic resin film 3 which has a large number of micropores bored therethrough, and is tightly attached to the paper sheet at the edge thereof by means of an adhesive material or heat seal. Consequently, even when the packing is wetted with water, the film 3 prevents the paper sheet 1 from being exposed to moisture, and when the packing undergoes sterilization the film 3 permits sterilizing gases to permeate through the micropores bored so that these gases can be easily introduced into the interior of dome 5 by passing through the paper sheet 1. Decreasing the diameter of the micropores 2 provided in said film 3 gives a greater advantage in that a quantity of moisture passing the film is decreased. However, it is diificult and impracticable to bore micropores of an extremely small diameter of less than 0.05 mm., for example, and it is unnecessary indeed to provide so fine micropores. Generally, micropores with a diameter of 0.1 mm. or less would not permit the passage of moisture unless a high pressure is applied.

The distribution density of the micropores 2 bored in film 3 regulates the rate at which sterilizing gases permeate into the dome 5 at the time of sterilizing treatment. Under ordinary sterilizing conditions the air in the dome is substituted with sterilizing gases such as ethyleneoxide containing 60 to of moisture in relative humidity. Sterilization is carried out by maintaining the interior of said dome in this condition for desired length of time. To carry out suificient sterilization without modifying the ordinary sterilizing conditions, it will be enough if sterilizing gases permeate at the rate of about 1 ml./sec. at a pressure of about 300 g./cm. If a film has micropores of 0.1 mm. diameter at the rate of one micropore per square millimeter, the film will permit the aforementioned rate of gas permeation.

There are various ways of boring micropores in a film with the aforementioned distribution density. One of the most appropriate manner consits in passing a film over the entire surface of a rotating roller having needles of the desired small diameter planted upright with the desired distribution density in such a manner that said film is pressed thereto, thus enabling said film to be bored with micropores of the desired diameter and distribution density. The film thus bored is placed and fastened to a paper sheet by means of joining such as heat seal.

Experiments were made to investigate the ability of these joined film and paper to prevent the permeation of bacteria when it was moistened. The samples used consisted of a sheet of bleached kraft paper 100 microns thick and a laminated sheet comprising the same paper sheet and a polyethylene film to 40 microns thick attached to one surface of said paper, said film having circular micropores about 0.1 mm. in diameter bored at the rate of one micropore per square millimeter. Both samples were folded in such a manner that they formed a rectangular dish (in the laminate, in such a manner that the samples constituted the outside of the dish) and then subjected to sterilizing treatment. Two types of liquid were prepared: (1) supernatant liquid obtained after solids settled down in a suspension dispersed a given amount of soil in water and (2) liquid comprising part of said supernatant liquid added to a liquid culture medium in order to culture the bacteria contained in the former. Each of these two types of liquid was mixed, the mixed liquid thus obtained was poured into separate dishes of both samples, each of said samples was floated on separate fresh liquid culture media, and then taken off one minute later, each of the liquid culture medium was preserved for further cultivation of bacteria, respectively. The culture media with the sample comprising only paper was observed to have discoloration due to the proliferation of bacteria, whereas the culture medium used with the laminated sample showed no evidence of bacteria. Next, the laminate sample dish was made to float on a liquid culture medium for 3 hours, while holding a bacteria-bearing liquid in it. After removing the dish, said liquid culture medium was observed as described above, but still it presented no existence of bacteria.

As mentioned above, the packing of hypodermic needle assembly has considerably improved its sterile condition even under the moistened condition undesirable for its storage, so that it can be used effectively at localities lacking sterilizing equipment such as affected areas Without concern over the degradation of its sterile state. Moreover, the synthetic resin film involved in this package of this invention which has a large number of fine micropores presents no difficulties in sterilizing the subject packing and also the cost of the film is negligibly low as against that of the whole packing, so that it will not afiect the efficiency of manufacturing the packing and the overall cost thereof.

What is claimed is:

1. An assembly for packing of a hypodermic needle comprising:

a paper sheet;

a synthetic resin film having a large number of micropores of less than 0.1 mm. in diameter bored therethrough, there being at least one micropore per square millimeter of synthetic resin film surface, to permit gas permeation of said film, said film being laminated to one surface of said paper sheet;

a covering of gas-impervious film fixed, except its central portion, to the opposite surface of said paper sheet to form a central hollow portion between said paper sheet and covering;

and a hypodermic needle inserted into a sheath and enclosed in the central hollow portion.

2. The packing of hypodermic needle assembly according to claim 1 wherein said base plate permits gas permeation through said micropores at the rate of at least 1 mL/sec. at a pressure of 300 g./cm.

References Cited UNITED STATES PATENTS 2,997,224 8/ 1961 Stannard 229-53 3,074,540 l/1963 Beich et a1. 206-43 3,253,705 5/1966 Stoker 206- 2,892,538 6/1959 Middleton, et a1. 206-43 FOREIGN PATENTS 1,152,475 9/1957 France.

JOSEPH R. LECLAIR, Primary Examiner.

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