Plunger rod and syringe

#This application is a U.S. national phase filing under 35 U.S.C. §371 of PCT Application No. PCT/JP2008/053603, filed Feb. 29, 2008, which is hereby incorporated in its entirety by reference.

#This invention relates to a plunger rod and a syringe, and more specifically, is concerned with a plunger rod for a syringe, said plunger rod being colored in part or in whole, and also with a high-identifiability syringe making use of the plunger rod.

#An administration of a drug solution to a patient by a syringe is carried out by a procedure such as that to be described hereinafter. After the drug solution is first drawn from an ampoule or vial and filled in a syringe barrel by using a plunger rod, the plunger rod is slowly pushed into the syringe barrel so that the drug solution is injected directly or via an infusion tube into a blood vessel or the like of the patient. Syringes, which are used as described above, are substantially the same in configuration from the request for giving priority to their basic function, and even among those having syringe barrels different in thickness and/or length because of differences in capacity, they all give a similar impression in appearance so that their own visual identifiability is extremely low. Further, syringes are fundamentally used with different kinds of drug solutions filled therein, respectively, as needed depending on the symptoms of patients. Before use, syringes of the same kind cannot hence be identified from each other at all from their appearances. In general, a syringe barrel is transparent, and a drug solution filled therein is visible from the outside. The drug solution is not characterized by color either so that, even when the drug solution has been filled in the syringe barrel, the thus-filled syringe is not provided with any substantially-improved visual identifiability. In a medical procedure, on the other hand, it is essential to absolutely avoid any misidentification or confusion with respect to each drug solution to be administered to a patient. For this purpose, it is necessary to permit clearly distinguishing a drug solution filled in a syringe barrel and its intended purpose when seen from the outside.

#The present invention will hereinafter be described in detail based on preferred embodiments. Descriptions will be made with reference to drawings that illustrate examples of certain preferred embodiments of the plunger rod according to the present invention. The plunger rod according to the present invention is characterized in that it is colored in part or in whole. FIG. 1 and FIG. 2 are perspective views showing examples of the plunger rod according to the present invention, both of which are colored in whole. FIG. 3, FIG. 4 and FIG. 6 are perspective views showing other examples of the plunger rod according to the present invention, all of which are colored only in part. A description will first be made about advantageous effects available from the use of the invention plunger rod constructed as described above.

#Considering that, if a syringe can be provided with enhanced visible identifiability by a simple measure without impairment to the function and safety required for the syringe, the above-described problems of the conventional syringes would be solved to provide a useful syringe which has high practical utility and enhanced convenience and which at the same time, can more effectively avoid an accident that a wrong drug solution would be administered to a patient, the present inventors have enthusiastically conducted investigations, and as a result, have led to the present invention. The present inventors first conducted an investigation on components of a syringe, that is, a syringe barrel, a piston which slides within the syringe barrel, and a plunger rod. As a result, with attention focused on the fact that among these components, the plunger rod has broader options with respect to its material compared with the other components because the plunger rod is not brought to direct contact with a drug solution, the present inventors came to a conclusion that it would be effective to make improvements in the plunger rod among the components of the syringe. As a result of a further investigation, it was found that, when plunger rods as components of plural syringes having the same configuration in external appearance are colored in part or in whole, their use would provide even the plural syringes themselves with enhanced individual visible identifiability, and moreover, their differences are extremely pronounced so that the individual syringes can be readily identified by simply taking a glance at them. A plunger rod can be formed from a synthetic resin, and therefore, it is extremely easy to color it in part or in whole. In addition, its color can be considered to be infinite. The coloring of the plunger rod can, therefore, meet any desire. Moreover, the coloring of the plunger rod in part or in whole is extremely easier as a processing step compared with modifications of its configuration, and does not significantly affect its manufacturing cost.

#A syringe itself can be provided with enhanced visual identifiability when its plunger rod as a component of the syringe is colored in part or in whole and the resulting colored plunger rod is used. As a consequence, the syringe can be used as will be described hereinafter. If syringes colored in different colors at colored parts of their plunger rods, for example, for respective kinds of drug solutions to be filled in their syringe barrels, respective concentrations of a drug solution, or respective administration routes such as oral and enteral administrations are provided and the syringe-color correlations are set to always remain constant, the details of the drug solution filled in each of the syringes can be instantly ascertained by simply taking a glance on it. A medical practitioner who is about to administer the drug solution by one of the syringes can, therefore, confirm the kind or the like of the drug solution filled in its syringe barrel by simply taking a glance at the colored part of its plunger rod, said colored part characterizing the syringe, in addition to ascertaining the drug solution based on an indication member such as a label. Further, the differences in color at the colored parts of the plunger rods, said colored parts characterizing the individual syringes, can be instantly recognized even by patients themselves or by other people around the patients and medical practitioners. Therefore, a patient or any other person around the patient and medical practitioner can also become readily aware of any mistake in syringe selection in a situation such that syringes of the same color are used routinely for the patient. It, therefore, becomes possible to avoid the accident that a wrong drug solution would be administered to a patient.