BLOW-MOLDED PLASTIC VESSEL FOR LIQUID MEDICINE

Abstract: A blow-molded plastic vessel (1) of a so-called "natural drop type" which is deformed at a barrel part thereof for pouring liquid medicine, enables liquid medicine to collect in a large quantity at the time of natural drop of contained liquid, and is free of dead space possibly formed by deformation resulting from back pressure. The vessel (1) is characterized by being composed in such manner that: a flat barrel part (2) whose width at cross-section along the longer axis is two times that along the shorter one or larger; a suspending part (4) is formed on the upper edge of said barrel part (2) and a mouth part (6) is at the center of the lower edge (5) of said barrel part (2), and the surfaces in parallel with the shorter axis at lower cross-section of the barrel part (2) is each formed like a wedge whereas those in parallel with a longer axis like a funnel tapering toward the mouth part (6).

Description: TECHNICAL FIELD The present invention relates to a flexible plastic container that is usable for intravenously administering such medicinal fluids as sugar solutions, electrolytic solutions, blood sugar amplifiers, osmotic diuretics, amino acid solutions, fat emulsion preparations, and high calorie solutions, as well as enteral nutrients, such as high protein nutrients, elemental nutrients and liquid foods. When applied to a so-called "natural dripping" type container, an internally filled medicinal fluid is administered through deformation of the container body by backpressure, thus avoiding the occurrence of dead space. A large fluid accumulating capability during natural drip is also featured in an embodiment as a plastic blow container for medicinal fluids. BACKGROUND ART Due to such advantages as not breaking even if dropped and light weight, plastic type medicinal fluid containers have rapidly progressed in recent years. Among these, natural dripping types are widely used, which utilize the flexibility of plastic materials whereby the body portion is deformed for administering the medicinal fluid. When used for natural dripping, since air is not supplied into the container during application, concern of contaminating organisms entering the container is absent, and there is a hygienic advantage. As an example of a plastic container for medicinal fluids, a type is disclosed in Japanese Laid-Open Patent Publication No. 158955/1989 (referred to below as prior art publication). The prior art publication indicates a unitized plastic container for medicinal fluids, in which an opening at the upper end of the container body is sealed by a stopper device, and at the bottom end of the body, a suspending fixture is provided. PROBLEMS RESOLVED BY THE INVENTION The plastic container for medicinal fluids indicated in the above mentioned prior art publication possesses a "square shoulder" type shape at the the upper end of the body through which the medicinal fluid passes. During natural dripping, backpressure soon ceases, and in the final stage of dripping, medicinal fluid remainder is left in this portion. The upper portion of the medicinal fluid is mainly used for natural dripping by backpressure and deformation proceeds from the top. For this reason, deformation in the final stage of dripping is at the opening side, thus forming the square shouldered shape. Backpressure transmission is difficult and this portion does not deform, thus producing a dead space during dripping. In addition, since the shape of the square shouldered portion impairs the medicinal fluid accumulating capability, a certain amount of medicinal fluid remains. CH-A-517 495 discloses a plastic blow container in accordance with the preamble of claim 1. The upper end of the flat shaped body of this known container has a rounded shape and comprises a filling opening. DISCLOSURE OF THE INVENTION The present invention as defined in claim 1 resolves the above mentioned problems possessed by the conventional blow containers when embodied as a plastic blow container for medicinal fluids. The present invention relates to a blow process formed plastic blow container for medicinal fluids which possesses a cross-section shape in which the long axis width is at least 4.0 times the short axis width, a flat shaped body at the upper end of which a suspending means is formed, and at the center of the bottom end of which an opening means is formed, and at the lower cross-section of the body section, the parallel sides of the short axis form a wedge shape, and the parallel sides of the long axis converge toward a funnel shape. This invention also features tapered shapes formed at the upper and lower ends of the body section. Particularly at the lower end cross-section short axis, the two parallel sides form a wedge shape with an angle α of less than 60°, and at the long axis side the parallel sides form a tapered funnel shape that converges to an angle β of less than 130° toward the opening means. By these provisions, the blow formed plastic blow container for medicinal fluids comprises a plastic container having, in the cross-section shape, a long axis width of at least 4.0 times the short axis width, and a flat shaped body at the top end of which a suspending means is formed and at the center of the bottom end of which an opening means is formed. As a result, a plastic blow container for medicinal fluids is obtained whereby backpressure during natural dripping is applied efficiently to the flat shaped body, an efficient natural dripping mode is obtained; and the bottom end shape of the body is such that in the cross-section short axis width the parallel sides form a wedge shape, and in the long axis the parallel sides converge to a funnel shape toward the opening means to provide a large medicinal fluid accumulating capability and avoid occurrence of dead space. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a direct view of a plastic blow container for medicinal fluids embodiment of this invention, Fig. 2 is a top view of this embodiment, Fig. 3 is a side view of this embodiment, Fig. 4 is an enlarged view of the opening section, Fig. 5 is a detailed side view of this embodiment when used in the natural dripping mode, Figs. 6 - 8 are graphs indicating relationships between fluid dripping rate and dripping amount. BEST MODE FOR CARRYING OUT THE INVENTION Following is a description with reference to the figures of a preferred embodiment of this invention as a plastic blow container for medicinal fluids. A plastic blow container for medicinal fluids 1 is blow formed from comparatively flexible plastic. In this grade plastic, tensile elasticity is 100 - 4000 kg/cm 2 (JISK7113). Among the types of materials suitable for forming this type of plastic are ethylene - vinyl acetate copolymer, high pressure method low density polyethylene, linear low pressure method low density polyethylene, low pressure method medium density polyethylene, α-olefin - propylene random copolymer containing 2 - 20 mol% α-olefin or α-olefin - propylene block copolymer, flexible polyvinyl chloride, ethyl group elastomer, styrene group elastomer, olefin group elastomer and urethane group elastomer. Also included are multilayer materials with intervening oxygen barrier type plastics such as saponified ethylene vinyl acetate copolymers, polyamids and polyvinyl alcohols formed in layers with these main structures. As shown in Figs. 1 - 3, the above type materials can be used to form a plastic blow container for medicinal fluids 1, comprising a flat shaped body 2, at the upper end 3 of which is a suspension means 4 provided as an integral structure of the body 2, and with lower end 5 formed to an opening means 6. The opening means 6 is provided with a stopper means 7 (shown in Fig. 5) which is heat sealed. Since the cross-section shape of the body 2 is flat, as shown in Fig. 2, with respect to the short axis width A, the long axis width B ratio is about 2.5. If this ratio B/A is less than 2.0, deformation by backpressure during natural dripping is reduced and ceases midway. Dripping does not proceed and residual fluid is produced. As shown in the Fig. 4 enlargement, at the body 2 bottom cross-section, on the short axis the parallel sides form a wedge shape at angle α, and on the long axis the parallel sides converge in a funnel shape at angle β toward opening means 6. Fig. 5 shows the container state when medicinal fluid is contained and natural dripping is performed. As natural dripping proceeds, deformation is conveyed from the top to the bottom of the body 2. At this time, since the parallel sides of the body 2 long axis form a tapering funnel shape toward the opening means 6, during natural dripping the medicinal fluid is efficiently accumulated in the lower portion of the body 2 and discharged. The above described plastic blow container for medicinal fluids 1 is blow formed of ethylene propylene random copolymer containing 6 mol % ethylene (tensile elasticity 3000 kg/cm 2 ). With respect to the Fig. 1 outline, each section shape is specified in Table 1 for comprising each type of plastic blow container for medicinal fluids. The weight of all of these plastic blow containers for medicinal fluids is 18 g and the average body section thickness is 0.3 mm. At this time, the bottom end radius of curvature R is formed for about 0.15 times the above mentioned angle α. α (degree) β (degree) Flatness Residual fluid (ml) Embodiment 1 45 100 4.0 0 Embodiment 2 60 100 4.0 0 Embodiment 3 45 110 4.0 0 Embodiment 4 45 130 4.0 0 Embodiment 5 45 100 2.0 0 Embodiment 6 45 100 3.0 0 Embodiment 7 45 100 6.0 0 Comparison example 1 65 100 4.0 30 Comparison example 2 45 140 4.0 0 Comparison example 3 45 100 1.5 40 These plastic blow containers for medicinal fluids 1 were suspended with the opening means 6 positioned downwards and dripping tests were performed. The containers were filled with 500 ml intravenous fluid (0.9 % isotonic saline solution) and 100 ml air. The opening means 6 were provided with internal rubber stoppers by stopper means 7 and heat sealed. Connecting needles 8 were inserted into the stopper means 7. Intravenous needles 9 from the medicinal fluid sets were fixed at the connecting needle 8 position. Medicinal fluid dripped through the intravenous needles 9 was received in messcylinders. In the dripping test, the time needed for dripping 25 ml, corresponding to 5 % of the contained 500 ml medicinal fluid, was first measured and recorded as the initial dripping time (T 0 ). Then the time required for dripping 25 ml (T n ) was measured for deriving the dripping speed ratio (T n /T 0 × 100). This dripping speed ratio was measured until medicinal fluid discharge stopped. Results of these dripping tests of plastic blow containers for medicinal fluids results are shown in Figs. 6 - 8. From Fig. 6, it can be recognized that when α exceeds 60°, variations are produced in the dripping fluid amount (for example in the dripping fluid amount 100 - 300 ml portion). Moreover, the medicinal fluid dripping cannot proceed to the final amount. Fig. 7 shows that when β exceeds 130 degree, even larger variations are produced in the dripping fluid amount and stable discharge cannot be obtained. Fig. 8 shows that when flatness is less than 2.0, dripping is not performed to completion. Deformation due to backpressure ceases midway in dripping and large amount of medicinal fluid remains. Consequently, by adopting the embodiment of this invention as a plastic blow container for medicinal fluids, backpressure is applied during natural dripping and a very efficient natural dripping mode can be obtained. Medicinal fluid accumulating capability is large and dripping proceeds without forming dead space. INDUSTRIAL APPLICABILITY In the above manner, this invention is applicable for use as an internally filled container for medicinal fluids such as sugar solutions, electrolytic solutions, blood sugar amplifiers, osmotic diuretics, amino acid solutions, fat emulsion preparations, high calorie solutions, enteral nutrients, high protein nutrients, elemental nutrients and liquid foods.

Claims: A plastic blow container (1) for medicinal fluids, said plastic blow container (1) being formed of flexible plastic having a tensile elasticity of 100 to 4000 Kg/cm 2 and having a flat shaped body (2) possessing in a plane normal to the longitudinale axis of the body a flat cross-sectional shape having a short-axis width (A) and a long-axis width (B); the upper end (3) of said flat shaped body (2) being formed into a suspension means (4); the center of the lower end (5) of said flat shaped body (2) being formed into an opening means (6); the lower end (5) of said flat shaped body (2) being tapered downward towards said opening means (6) in a manner such that at said lower end the opposing shorter sides of said flat shaped body (2) converge towards each other in the direction of the opening means (6) under an angle (β) defining a funnel shape and the opposing longer sides of said flat shaped body (2) converge towards each other in the direction of the opening means (6) under an angle (α) defining a wedge shape; characterized in that the long-axis width (B) of said flat shaped body (2) is at least 4.0 times its short-axis width (A), and that the upper end (3) of said flat shaped body (2) is also formed into a tapered shape upwards towards said suspension means (4). The plastic blow container for medical fluids according to claim 1, wherein the angle (β) of convergence defining a funnel shape is less than 130 degrees and the angle (α) of convergence defining a wedge shape is less than 60 degrees.

Inventors: MATSUMOTO KAZUYA, SUMI TAKEHIKO, MATSUMOTO, KAZUYA, SUMI, TAKEHIKO
Applicants: KYORAKU CO LTD, Q P CORP, KYORAKU CO., LTD., Q.P. CORPORATION
Application year: 1991
Main classification: A61J1
IPC codes: A61B19, A61J1