JP6741335B2 - Method for evaluating pain caused by drug administration and method for selecting drug administration - Google Patents

Method for evaluating pain caused by drug administration and method for selecting drug administration Download PDF

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JP6741335B2
JP6741335B2 JP2014257428A JP2014257428A JP6741335B2 JP 6741335 B2 JP6741335 B2 JP 6741335B2 JP 2014257428 A JP2014257428 A JP 2014257428A JP 2014257428 A JP2014257428 A JP 2014257428A JP 6741335 B2 JP6741335 B2 JP 6741335B2
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JP2016116626A (en
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のぞみ 網
のぞみ 網
滋 玉造
滋 玉造
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TRUMO KABUSHIKI KAISHA
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本発明は、薬液投与による痛みの評価方法及び薬液投与の選定方法に関する。 The present invention relates to a method for evaluating pain caused by administration of a drug solution and a method for selecting drug solution administration.

注射は最も用いられている薬液投与方法であるが、注射による痛みは患者にとって不快である。このため、注射による痛みを低減することが望まれている。注射による痛みには、注射針の穿刺による痛みと薬液(薬液の注入)による痛みがある。従って、注射による痛みを低減するためには、穿刺による痛みと薬液投与による痛みをそれぞれ評価(定量化)できることが必要である。 Although injection is the most commonly used method of administering drug solutions, the pain caused by injection is uncomfortable for the patient. Therefore, it is desired to reduce the pain caused by injection. The pain caused by injection includes pain caused by puncture of an injection needle and pain caused by a drug solution (injection of drug solution). Therefore, in order to reduce the pain caused by injection, it is necessary to be able to evaluate (quantify) the pain caused by puncture and the pain caused by administration of the liquid medicine.

これに関連し、下記非特許文献1では、麻酔したラットの脊髄反射で針の穿刺による痛みを評価する方法が提案されている。また、下記非特許文献2では、筋電図(EMG)から血管の痛みを評価する方法が提案されている。 In connection with this, Non-Patent Document 1 below proposes a method for evaluating pain due to needle puncture by spinal reflex of anesthetized rat. In addition, Non-Patent Document 2 below proposes a method of evaluating pain in a blood vessel from an electromyogram (EMG).

岡本(Okamoto,K)、網(Ami,N)、大島(Oshima,H)、「麻酔ラットにおける屈筋反射反応と針挿入の痛みの評価(Assessment of needle insertion pain with flexor reflex responses in anesthetized rats)」、Pain Research、日本疼痛学会、2012年、第27巻、第24号、p.215−225Okamoto (Okamoto, K), Omi (Ami, N), Oshima (Oshima, H), "Assessment of needle insertion pain reflex versesnese". , Pain Research, Japan Pain Society, 2012, Vol. 27, No. 24, p. 215-225 (Masumi,S)、(Senba,E)、「麻酔ラットにおける脂肪乳剤誘発による血管の痛みにおける一酸化窒素の関与(Nitric oxide involvement in lipid emulsion−induced vascular pain in anesthetized rats)」、Eur J Pharmacol、Elsevier、2008年、第594号、p.64−69(Masumi, S), (Senba, E), "Nitride oxide in Lipid Emulsion-Induced Vascular Pain in Anesthetized Pour,". Elsevier, 2008, 594, p. 64-69

しかしながら、従来では、薬液投与による痛みを評価(定量化)する有効な方法についての提案はなされていなかった。 However, conventionally, no proposal has been made on an effective method for evaluating (quantifying) pain caused by administration of a drug solution.

本発明はこのような課題を考慮してなされたものであり、薬液投与による痛みの評価方法及び薬液投与の選定方法を提供することを目的とする。 The present invention has been made in consideration of such problems, and an object thereof is to provide a method for evaluating pain caused by administration of a drug solution and a method for selecting drug solution administration.

上記の目的を達成するため、本発明に係る薬液投与による痛みの評価方法では、身体の所定部位と、前記所定部位に刺激を与えた際に脊髄反射によって屈曲する骨格筋とを有する哺乳類の実験動物を準備し、前記実験動物を吸入麻酔にて麻酔し、麻酔された前記実験動物の前記骨格筋に測定電極を挿入し、前記骨格筋の筋電位を前記測定電極で測定しながら、麻酔された前記実験動物の前記所定部位に注射針を穿刺し、前記注射針の穿刺による筋電反応が消えた後に、麻酔された前記実験動物に前記注射針を介して薬液を投与し、前記薬液の投与による筋電反応の持続時間の測定、及び前記薬液の投与による前記筋電反応が生じてから消えるまでの筋電位の絶対値を積分したEMG強度の測定の少なくとも一方を行う、ことを特徴とする。 In order to achieve the above-mentioned object, in the method for evaluating pain caused by administration of a drug solution according to the present invention, an experiment on a mammal having a predetermined part of the body and skeletal muscles that bend by spinal reflex when the predetermined part is stimulated An animal is prepared, the experimental animal is anesthetized by inhalation anesthesia, a measurement electrode is inserted into the skeletal muscle of the anesthetized experimental animal, and anesthesia is anesthetized while measuring the myoelectric potential of the skeletal muscle with the measurement electrode. A needle is punctured in the predetermined site of the experimental animal, and after the myoelectric reaction due to the puncture of the injection needle disappears, a drug solution is administered to the anesthetized experimental animal via the needle, At least one of the measurement of the duration of the myoelectric reaction due to administration and the measurement of the EMG intensity obtained by integrating the absolute value of the myoelectric potential from the occurrence of the myoelectric response due to the administration of the drug solution to the disappearance thereof are performed. To do.

上記の本発明の方法によれば、注射針の穿刺による筋電反応が消えた後に実験動物に薬液を投与して薬液投与による筋電反応を測定するので、筋電図(EMG)上で穿刺による筋電反応と薬液投与による筋電反応とが重なることがない。これにより、穿刺による痛みと分けて、薬液投与による痛みを評価(定量化)することができる。また、ヒトが感じる痛みは、実験動物を用いた筋電反応の結果と同様の傾向を示すため、本発明の方法により、ヒトに注射した場合の薬液投与による痛みを評価することが可能である。従って、本発明の方法によれば、より痛みの低減されたヒト用の薬液注射の開発に寄与することができる。 According to the above method of the present invention, after the myoelectric reaction due to the puncture of the injection needle disappears, the medicinal solution is administered to the experimental animal and the myoelectric reaction due to the medicinal solution administration is measured, so that the puncture is performed on the electromyogram (EMG). The myoelectric reaction due to and the myoelectric reaction due to administration of the drug solution do not overlap. This makes it possible to evaluate (quantify) the pain caused by the administration of the drug solution separately from the pain caused by the puncture. Further, since the pain felt by humans shows the same tendency as the result of myoelectric reaction using experimental animals, the method of the present invention makes it possible to evaluate the pain caused by administration of a drug solution when injected into humans. .. Therefore, according to the method of the present invention, it is possible to contribute to the development of a drug injection for humans with less pain.

上記の薬液投与による痛みの評価方法において、前記実験動物の前記所定部位の複数の投与箇所に、組成の異なる複数の前記薬液を同じ投与条件で投与し、又は同一組成の前記薬液を異なる投与条件で投与してもよい。 In the method for evaluating pain caused by administration of the above-mentioned medicinal solution, a plurality of medicinal solutions having different compositions are administered under the same administration conditions, or a plurality of medicinal solutions having the same composition are administered under different administration conditions at a plurality of administration sites of the predetermined site of the experimental animal. May be administered in.

このように、同じ実験動物で複数箇所に投与することにより、薬液組成又は投与条件による痛みの違いを比較することができ、より痛みの少ない薬液又は投与条件を選定することができる。 In this way, by administering to the same experimental animal at a plurality of sites, it is possible to compare the difference in pain depending on the composition of the liquid medicine or the administration conditions, and it is possible to select the liquid medicine or the administration condition with less pain.

上記の薬液投与による痛みの評価方法において、前記実験動物は、ラットであってもよい。 In the above-mentioned method for evaluating pain caused by administration of a drug solution, the experimental animal may be a rat.

上記の薬液投与による痛みの評価方法において、前記所定部位は足底皮下であり、前記骨格筋は半腱様筋であってもよい。 In the above-described method of evaluating pain caused by administration of a liquid medicine, the predetermined site may be subcutaneous of the sole of the foot and the skeletal muscle may be a semitendinosus muscle.

上記の薬液投与による痛みの評価方法において、前記複数の投与箇所における一箇所当たりの投与量は10〜100μLであってもよい。 In the above-described method for evaluating pain caused by administration of a drug solution, the dose per site at the plurality of administration sites may be 10 to 100 μL.

上記の薬液投与による痛みの評価方法において、隣接する前記投与箇所同士の間隔を2mm以上あけてもよい。 In the above-mentioned method for evaluating pain caused by administration of a drug solution, the interval between adjacent administration sites may be 2 mm or more.

これにより、薬液投与による筋電反応の取得において、隣接する投与箇所による影響を回避し、精度の高い測定が可能となる。 This makes it possible to avoid the influence of the adjacent administration site in obtaining the myoelectric reaction due to the administration of the drug solution, and to perform highly accurate measurement.

上記の薬液投与による痛みの評価方法において、前記複数の投与箇所での総投与量は200μL以下であってもよい。 In the above-described method of evaluating pain caused by administration of a drug solution, the total dose at the plurality of administration sites may be 200 μL or less.

上記の薬液投与による痛みの評価方法において、前記薬液の投与速度は5〜100μL/secであってもよい。 In the above-mentioned method for evaluating pain caused by administration of a drug solution, the administration rate of the drug solution may be 5 to 100 μL/sec.

上記の薬液投与による痛みの評価方法において、穿刺による前記筋電反応が消えてから1秒以上経過した後に、前記薬液の投与を開始してもよい。 In the above-described method of evaluating pain caused by administration of a liquid medicine, the administration of the liquid medicine may be started 1 second or more after the myoelectric reaction due to puncture disappears.

これにより、穿刺による筋電反応と分けて、薬液投与による筋電反応をより効果的に測定することができる。 Accordingly, the myoelectric reaction due to the administration of the drug solution can be more effectively measured separately from the myoelectric reaction due to the puncture.

上記の薬液投与による痛みの評価方法において、穿刺による前記筋電反応が生じた場合にのみ前記薬液を投与してもよい。 In the above-described method for evaluating pain caused by administration of a drug solution, the drug solution may be administered only when the myoelectric reaction due to puncture occurs.

これにより、無駄な薬液投与を回避することができる。 This makes it possible to avoid wasteful administration of the drug solution.

上記の薬液投与による痛みの評価方法において、前記測定電極として双極電極を用い、前記実験動物の胸部皮膚に基準電極を貼付してもよい。 In the above-described method of evaluating pain caused by administration of a drug solution, a bipolar electrode may be used as the measurement electrode, and a reference electrode may be attached to the chest skin of the experimental animal.

これにより、ノイズの少ない筋電位波形を取得することができ、測定精度を向上させることができる。 Thereby, the myoelectric potential waveform with less noise can be acquired, and the measurement accuracy can be improved.

また、本発明に係る薬液投与の選定方法は、身体の所定部位と、前記所定部位に刺激を与えた際に脊髄反射によって屈曲する骨格筋とを有する哺乳類の実験動物を準備する準備ステップと、前記実験動物を吸入麻酔にて麻酔する麻酔ステップと、麻酔された前記実験動物の前記骨格筋に測定電極を留置する測定電極留置ステップと、前記骨格筋の筋電位を前記測定電極で測定しながら、麻酔された前記実験動物の前記所定部位に注射針を穿刺する穿刺ステップと、前記注射針の穿刺による筋電反応が消えた後に、麻酔された前記実験動物に前記注射針を介して薬液を投与する投与ステップと、前記薬液の投与による筋電反応が生じてから消えるまでの前記筋電位の絶対値を積分したEMG強度の測定、及び前記薬液の投与による前記筋電反応の持続時間の測定の少なくとも一方を行う測定ステップと、を含み、組成の異なる複数の薬液毎に、又は複数の投与条件毎に、前記穿刺ステップ、前記投与ステップ及び前記測定ステップを行い、さらに、組成の異なる前記複数の薬液のうち、前記持続時間が最も短い、あるいは前記EMG強度が最も小さい薬液組成、又は前記複数の投与条件のうち、前記持続時間が最も短い、あるいは前記EMG強度が最も小さい投与条件を特定する特定ステップを含む、ことを特徴とする。 Further, the method for selecting the administration of a liquid medicine according to the present invention, a preparatory step of preparing a mammalian experimental animal having a predetermined part of the body, and a skeletal muscle that is bent by spinal reflex when the predetermined part is stimulated, Anesthesia step of anesthetizing the experimental animal by inhalation anesthesia, measurement electrode placement step of placing a measurement electrode in the skeletal muscle of the anesthetized experimental animal, while measuring the myoelectric potential of the skeletal muscle with the measurement electrode A puncturing step of puncturing the predetermined site of the anesthetized experimental animal with an injection needle; and after the myoelectric reaction due to the puncture of the injection needle disappears, a drug solution is applied to the anesthetized experimental animal via the injection needle. Administration step for administration, measurement of EMG intensity by integrating absolute value of the myoelectric potential from generation to disappearance of myoelectric response due to administration of the drug solution, and measurement of duration of the myoelectric response due to administration of the drug solution A measurement step of performing at least one of, and for each of a plurality of drug solutions having different compositions, or for each of a plurality of administration conditions, the puncturing step, the administration step and the measurement step, further, the plurality of different composition Of the drug solution, the drug solution composition with the shortest duration or the smallest EMG intensity, or the administration condition with the shortest duration or the least EMG intensity among the plurality of administration conditions is specified. It is characterized by including a specific step.

この方法によれば、痛みの少ない薬液組成又は投与条件を選定することができる。 According to this method, a drug solution composition or administration condition with less pain can be selected.

本発明の薬液投与による痛みの評価方法によれば、穿刺による痛みと分けて、薬液投与による痛みを評価(定量化)することができる。また、本発明の薬液投与の選定方法によれば、痛みの少ない薬液組成又は投与条件を選定することができる。 According to the method for evaluating pain due to administration of a liquid medicine of the present invention, it is possible to evaluate (quantify) pain due to administration of a liquid medicine separately from pain due to puncture. Further, according to the method for selecting a drug solution administration of the present invention, a drug solution composition or administration condition with less pain can be selected.

本発明の方法に用いる一構成例に係る測定システムの概略図である。It is a schematic diagram of a measuring system concerning one example of composition used for a method of the present invention. 本発明の方法によって得られる筋電位波形の一例である。It is an example of the myoelectric potential waveform obtained by the method of the present invention. 図3Aは、組成の異なる複数の薬液をラットに注射した場合の各薬液の投与による筋電反応の持続時間を示すグラフであり、図3Bは、組成の異なる複数の薬液をラットに注射した場合の各薬液の投与による筋電反応から得たEMG強度を示すグラフである。FIG. 3A is a graph showing the duration of myoelectric reaction due to administration of each drug solution when a plurality of drug solutions having different compositions are injected into a rat, and FIG. 3B is a graph showing a case where a plurality of drug solutions having different compositions are injected into a rat. 5 is a graph showing the EMG intensity obtained from the myoelectric reaction due to the administration of each drug solution in FIG. 図4Aは、生理食塩水を異なる複数の注入量にてヒトに注射した場合の痛みの大きさ(VAS)を示すグラフであり、図4Bは、生理食塩水を異なる複数の投与量にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。FIG. 4A is a graph showing the pain magnitude (VAS) when physiological saline is injected into a human at different injection doses, and FIG. 4B is a graph showing physiological saline in rats at different injection doses. 3 is a graph showing the EMG intensity obtained from the myoelectric reaction by the injection solution when injected into the mouse. 図5Aは、異なる複数のpH値でヒトに注射した場合の痛みの大きさ(VAS)を示すグラフであり、図5Bは、異なる複数のpH値でラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。FIG. 5A is a graph showing the pain magnitude (VAS) when injected into humans at different pH values, and FIG. 5B is the myoelectric potential of the injection solution when injected into rats at different pH values. It is a graph which shows the EMG intensity|strength obtained from reaction. 図6Aは、5%NaClをヒトに注射した場合の痛みの大きさ(VAS)の時間経過を示すグラフであり、図6Bは、NaClを異なる複数の濃度にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。FIG. 6A is a graph showing the time course of pain magnitude (VAS) when 5% NaCl was injected into a human, and FIG. 6B is an injection solution when NaCl was injected into a rat at different concentrations. 5 is a graph showing the EMG intensity obtained from the myoelectric reaction according to FIG. 図7Aは、グルタミン酸を異なる複数のモル濃度にてヒトに注射した場合の痛みの大きさ(VAS)を示すグラフであり、図7Bは、グルタミン酸を異なる複数のモル濃度にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。FIG. 7A is a graph showing the pain magnitude (VAS) when glutamic acid was injected into humans at different molar concentrations, and FIG. 7B is when glutamate was injected into rats at different molar concentrations. 2 is a graph showing the EMG intensity obtained from the myoelectric reaction with the injection solution of 1. 図8Aは、ポリエチレングリコール・生理食塩水混合液を異なる複数の粘度にてラットに注射した場合の注射液による筋電反応の持続時間を示すグラフであり、図8Bは、ポリエチレングリコール・生理食塩水混合液を異なる複数の粘度にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。FIG. 8A is a graph showing the duration of myoelectric reaction by an injection solution when a mixture of polyethylene glycol/physiological saline solution is injected into a rat at different viscosities, and FIG. 8B is a polyethylene glycol/physiological saline solution. It is a graph which shows the EMG intensity|strength obtained from the myoelectric reaction by the injection liquid when a mixed liquid is injected into a rat with several different viscosity. 図9Aは、リン酸緩衝生理食塩水(pH5)を異なる複数の投与速度にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフであり、図9Bは、10%NaClを異なる複数の投与速度にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。FIG. 9A is a graph showing EMG intensity obtained from myoelectric reaction by an injection solution when phosphate buffered saline (pH 5) was injected into a rat at different administration rates, and FIG. 9B is 10%. It is a graph which shows the EMG intensity|strength obtained from the myoelectric reaction by the injection liquid when NaCl is injected into a rat at a several different administration rate. 本発明の実施例を示すグラフであって、pHが異なる複数の薬液(炎症性自己免疫疾患治療用の注射用水性製剤)をラットに注射した場合の薬液投与による筋電反応から得たEMG強度を示すグラフである。It is a graph which shows the Example of this invention, Comprising: The EMG intensity|strength obtained from the myoelectric reaction by the chemical|medical solution administration at the time of injecting a rat with several chemical|medical solutions with different pH (aqueous formulation for injection for inflammatory autoimmune disease treatment) It is a graph which shows.

以下、本発明に係る薬液投与による痛みの評価方法及び薬液投与の選定方法について好適な実施形態を挙げ、添付の図面を参照しながら説明する。 Hereinafter, a method for evaluating pain by administration of a drug solution and a method for selecting a drug solution according to the present invention will be described with reference to the accompanying drawings, with reference to preferred embodiments.

図1は、本発明の方法に用いる一構成例に係る測定システム10の概略図である。図1に示す本実施形態において、薬液投与による痛みの評価のために使用する被検体(実験動物)はラット12である。使用し得るラット12の条件としては、例えば、7〜10週齢、体重200〜400g、系統はSD(他の系統でも可)である。ラット12の順化・検疫期間は5日間以上とするのが好ましい。ラット12には麻酔用マスク13を装着し、吸入麻酔をする。 FIG. 1 is a schematic diagram of a measurement system 10 according to a configuration example used in the method of the present invention. In the present embodiment shown in FIG. 1, the subject (experimental animal) used to evaluate pain caused by administration of a drug solution is rat 12. The rat 12 conditions that can be used are, for example, 7 to 10 weeks of age, a body weight of 200 to 400 g, and a strain of SD (other strains may be used). The acclimatization/quarantine period of the rat 12 is preferably 5 days or more. An anesthesia mask 13 is attached to the rat 12 to perform anesthesia by inhalation.

なお、使用し得る実験動物は、身体の所定部位と、所定部位に刺激を与えた際に脊髄反射によって屈曲する骨格筋とを有する哺乳類であればよい。ラット12の場合、足底皮下12aに刺激を与えた際に脊髄反射によって半腱様筋12bが屈曲する。ラット12以外に使用し得る哺乳類の実験動物としては、例えば、マウス、モルモット、スナネズミ、ハムスター、フェレット、ウサギ、イヌ、ミニブタ等が挙げられる。 The experimental animal that can be used may be a mammal having a predetermined part of the body and a skeletal muscle that bends due to spinal reflex when a predetermined part is stimulated. In the case of the rat 12, the semitendinosus muscle 12b is bent by spinal reflex when the foot sole subcutaneous 12a is stimulated. Examples of mammalian experimental animals that can be used in addition to rat 12 include mice, guinea pigs, gerbils, hamsters, ferrets, rabbits, dogs, miniature pigs, and the like.

薬液はシリンジ14に充填される。シリンジ14の容量は例えば、1〜10mLである。シリンジ14は樹脂製の軟質チューブ16を介して注射針18に接続されている。適用し得る注射針18のサイズは、例えば、34G〜22Gである。注射針18はラット12の足底皮下12aに穿刺される。 The liquid medicine is filled in the syringe 14. The capacity of the syringe 14 is, for example, 1 to 10 mL. The syringe 14 is connected to an injection needle 18 via a soft tube 16 made of resin. The applicable size of the injection needle 18 is, for example, 34G to 22G. The injection needle 18 is punctured under the foot 12 of the rat 12.

シリンジ14はシリンジポンプ20に装着される。シリンジポンプ20は、装着されたシリンジ14の押子14aを押すスライダ22を備える。シリンジポンプ20では、設定された送液量とシリンジ14の種類(容量)に基づいて、スライダ22で押子14aを押し込む速度を決定する。これにより、ラット12への薬液の投与速度を任意に設定することができる。薬液の投与速度は例えば5〜100μL/secである。 The syringe 14 is attached to the syringe pump 20. The syringe pump 20 includes a slider 22 that pushes the pusher 14 a of the mounted syringe 14. In the syringe pump 20, the speed at which the slider 22 pushes the pusher 14a is determined based on the set liquid delivery amount and the type (capacity) of the syringe 14. Thereby, the administration speed of the drug solution to the rat 12 can be set arbitrarily. The administration rate of the drug solution is, for example, 5 to 100 μL/sec.

薬液投与による痛みを測定するために、ラット12の大腿部の半腱様筋12bの筋電位を記録する。筋電位の記録においては、針状の測定電極24(例えば、双極釣針電極)を半腱様筋12bに穿刺して留置するともに、胸部皮膚12cに基準電極26を貼付する。測定電極24及び基準電極26からの電位信号は、高感度生体電気増幅器28によって増幅され、データ収集装置30に送信される。 In order to measure pain caused by administration of the drug solution, the myoelectric potential of the semitendinosus muscle 12b of the thigh of the rat 12 is recorded. In recording the myoelectric potential, a needle-shaped measurement electrode 24 (for example, a bipolar fishhook electrode) is punctured and placed in the semitendinosus muscle 12b, and the reference electrode 26 is attached to the chest skin 12c. The potential signals from the measurement electrode 24 and the reference electrode 26 are amplified by the high-sensitivity bioelectrical amplifier 28 and transmitted to the data acquisition device 30.

データ収集装置30では、所定のサンプリング間隔(例えば、0.1ms)でデータ(電位信号)を記録し、筋電位波形を生成する。パーソナルコンピュータ32では、データ収集装置30により生成された筋電位波形をモニタ画面32aに表示する。 The data acquisition device 30 records data (electric potential signal) at a predetermined sampling interval (for example, 0.1 ms) and generates a myoelectric potential waveform. The personal computer 32 displays the myoelectric potential waveform generated by the data acquisition device 30 on the monitor screen 32a.

また、この測定システム10では、注射による筋電反応を測定する前準備として、筋電反応(筋肉の収縮)を測定できる麻酔深度に調節するために、クリップ型刺激電極34を使用した電気刺激を行う。クリップ型刺激電極34は、図示しない電気刺激装置に接続されている。 In addition, in this measurement system 10, as a preparation for measuring the myoelectric reaction by injection, electrical stimulation using the clip-type stimulation electrode 34 is performed in order to adjust the anesthesia depth at which the myoelectric reaction (contraction of muscle) can be measured. To do. The clip-type stimulation electrode 34 is connected to an electric stimulation device (not shown).

薬液投与による痛みの評価方法及び薬液投与の選定方法は、上記のように構成された測定システム10を用いる場合、例えば以下のように行うことができる。 When the measuring system 10 configured as described above is used, the method for evaluating pain due to administration of a drug solution and the method for selecting a drug solution can be performed as follows, for example.

異なる複数の薬液組成からどの組成が最も痛みが少ないかを調べたい場合には、組成の異なる複数の薬液を準備する。薬液組成の違いは、例えば、薬液成分(例えば、有効成分の化学構造、バッファー、安定化剤、酸化防止剤等)の種類、pH値、粘度等による。あるいは、異なる複数の投与条件からどの投与条件が最も痛みが少ないかを調べたい場合には、同一組成の薬液について異なる複数の投与条件を計画する。投与条件のパラメータとしては、薬液の投与速度(注入速度)、投与量が挙げられる。 When it is desired to find out which composition has the least pain from a plurality of different drug solution compositions, a plurality of drug solutions having different compositions are prepared. The difference in the chemical liquid composition depends on, for example, the type of the chemical liquid component (for example, the chemical structure of the active ingredient, the buffer, the stabilizer, the antioxidant, etc.), the pH value, the viscosity and the like. Alternatively, when it is desired to investigate which administration condition produces the least pain from a plurality of different administration conditions, different administration conditions are planned for the drug solution having the same composition. The parameters of the administration conditions include the administration rate (infusion rate) of the drug solution and the dose.

被検体となるラット12を準備し(準備ステップ)、ラット12に吸入麻酔をする(麻酔ステップ)。適用可能な吸入麻酔薬としては例えばイソフルランが挙げられる。空気に対する麻酔濃度は、麻酔導入時で例えば3〜4%/Airであり、記録時で例えば1〜2%/Airである。なお、安定したデータを得るため、麻酔中は、保温マットによりラット12を加温し、体温を一定に保つことが好ましい。 The rat 12 as a subject is prepared (preparation step), and the rat 12 is anesthetized by inhalation (anesthesia step). Examples of applicable inhalation anesthetics include isoflurane. Anesthesia concentration with respect to air is, for example, 3 to 4%/Air when anesthesia is introduced, and is 1 to 2%/Air when recording. In order to obtain stable data, it is preferable to heat the rat 12 with a heat retaining mat during anesthesia to keep the body temperature constant.

次に、麻酔されたラット12の半腱様筋12bに測定電極24を留置する(測定電極留置ステップ)。具体的には、クリップ型刺激電極34でラット12の後肢の甲と裏を挟み込み、図示しない電気刺激装置により、クリップ型刺激電極34を介して痛覚のC繊維に電気刺激(例えば、40Hz、10mA、2ms)を与える。このとき収縮が認められた位置の大腿部皮膚を約1cm程度切開して半腱様筋12bを露出させてから、測定電極24を挿入する。 Next, the measurement electrode 24 is placed on the semitendinosus muscle 12b of the anesthetized rat 12 (measurement electrode placement step). Specifically, the instep and the back of the hind limb of the rat 12 are sandwiched by the clip-type stimulation electrodes 34, and an electric stimulator (not shown) is used to electrically stimulate the C-fibers of pain via the clip-type stimulation electrodes 34 (for example, 40 Hz, 10 mA). 2 ms). At this time, the thigh skin at the position where contraction is recognized is incised by about 1 cm to expose the semitendinosus muscle 12b, and then the measurement electrode 24 is inserted.

測定電極24を留置したら、クリップ型刺激電極34を介して図示しない電気刺激装置により再び電気刺激(例えば、40Hz、5mA、2ms)を与え、筋電反応強度を参照しながら、ラット12の麻酔深度を微調整する。その後、麻酔深度を一定に保持する。 After the measurement electrode 24 is placed, electric stimulation (for example, 40 Hz, 5 mA, 2 ms) is applied again by an electric stimulator (not shown) via the clip-type stimulating electrode 34, and the anesthesia depth of the rat 12 is checked with reference to the myoelectric reaction intensity. Fine-tune. After that, the anesthesia depth is kept constant.

また、ラット12の胸部を脱毛して胸部皮膚12cを露出させた後、胸部皮膚12cに基準電極26を貼付する。なお、基準電極26の貼付は、測定電極24の留置の前でも後でもよく、あるいは並行して行ってもよい。測定電極24として双極電極を用いるとともに、ラット12の胸部皮膚12cに基準電極26を貼付すると、ノイズの少ない筋電位波形を取得することができ、測定精度を向上させることができる。なお、基準電極26を貼付する場合には、測定電極24は単極電極であってもよい。 Further, the chest of the rat 12 is depilated to expose the chest skin 12c, and then the reference electrode 26 is attached to the chest skin 12c. The reference electrode 26 may be attached before or after the measurement electrode 24 is placed, or in parallel. When a bipolar electrode is used as the measurement electrode 24 and the reference electrode 26 is attached to the chest skin 12c of the rat 12, a myoelectric potential waveform with less noise can be acquired and the measurement accuracy can be improved. When the reference electrode 26 is attached, the measurement electrode 24 may be a monopolar electrode.

以上の準備が整ったら、同一のラット12を用いて、組成の異なる複数の薬液毎に、又は複数の投与条件毎に、以下に説明する穿刺ステップ、投与ステップ及び測定ステップを行う。すなわち、ある薬液組成又は投与条件にて穿刺ステップ、投与ステップ及び測定ステップを行った後に、同一のラット12を用いて、別の薬液組成又は投与条件にて穿刺ステップ、投与ステップ及び測定ステップを行うことを繰り返す。 When the above preparation is completed, the same rat 12 is used to perform the puncture step, administration step, and measurement step described below for each of a plurality of drug solutions having different compositions or for each of a plurality of administration conditions. That is, after performing the puncturing step, the administering step and the measuring step under a certain liquid composition or administration condition, the same rat 12 is used to perform the puncturing step, the administering step and the measurement step under different drug composition or administration conditions. Repeat that.

穿刺ステップでは、麻酔されたラット12の足底皮下12aに注射針18を穿刺する。この場合、注射針18の先端部に設けられた刃面全体が足底皮下12aに刺さったら穿刺完了である。このように注射針18をラット12に穿刺すると、穿刺による筋電反応が生じる。 In the puncturing step, the injection needle 18 is punctured into the plantar subcutaneous 12a of the anesthetized rat 12. In this case, the puncture is complete when the entire blade surface provided at the tip of the injection needle 18 pierces the subcutaneous foot 12a. When the injection needle 18 is punctured in the rat 12 in this manner, a myoelectric reaction occurs due to the puncture.

穿刺ステップに続く投与ステップでは、注射針18の穿刺による筋電反応が消えた後に、麻酔されたラット12に注射針18を介して薬液を投与する。この場合、シリンジポンプ20は予め設定された投与速度及び投与量に基づきシリンジ14の押子14aを押し込むことにより、薬液は、設定された投与速度及び投与量でラット12の足底皮下12aに注入される。 In the administration step following the puncture step, after the myoelectric reaction due to the puncture of the injection needle 18 disappears, the medicinal solution is administered to the anesthetized rat 12 via the injection needle 18. In this case, the syringe pump 20 pushes the pusher 14a of the syringe 14 on the basis of a preset administration speed and dose, so that the drug solution is injected into the plantar subcutaneous 12a of the rat 12 at the preset administration speed and dose. To be done.

なお、各投与ステップにおいて、隣接する投与箇所(穿刺箇所)同士の間隔は、一箇所当たりの投与量が100μL以下の場合で2mm以上あけることが好ましい。これにより、薬液投与による筋電反応の取得において、隣接する投与箇所による影響を回避し、精度の高い測定が可能となる。 In addition, in each administration step, the interval between adjacent administration sites (puncture sites) is preferably 2 mm or more when the dose per site is 100 μL or less. This makes it possible to avoid the influence of the adjacent administration site in obtaining the myoelectric reaction due to the administration of the drug solution, and to perform highly accurate measurement.

組成の異なる複数の薬液を試験する場合には、各投与ステップでの薬液の投与速度及び投与量を同じにする。また、同一組成の薬液について複数の投与条件を試験する場合には、各投与ステップにおいて、薬液の投与速度と投与量の一方又は両方を変えて、薬液を投与する。 When a plurality of drug solutions having different compositions are tested, the dosing rate and dose of the drug solution in each administration step should be the same. Further, when a plurality of administration conditions are tested for a drug solution having the same composition, one or both of the drug solution administration rate and the dose are changed in each administration step.

ラット12の足底サイズを考慮すると、複数の投与箇所における一箇所当たりの投与量は10〜100μLであることが好ましい。また、複数の投与箇所でのラット12への総投与量は200μL以下であることが好ましい。例えば、投与量と投与箇所数の組合せは、20μL×8箇所(=160μL)、50μL×4箇所(=200μL)、100μL×2箇所(200μL)等が挙げられる。また、薬液の投与速度は、例えば、5〜100μL/secである。 Considering the plantar size of the rat 12, it is preferable that the dose per site at a plurality of administration sites is 10 to 100 μL. Further, the total dose to rat 12 at a plurality of administration sites is preferably 200 μL or less. For example, the combination of the dose and the number of administration sites includes 20 μL×8 places (=160 μL), 50 μL×4 places (=200 μL), 100 μL×2 places (200 μL), and the like. The administration rate of the drug solution is, for example, 5 to 100 μL/sec.

なお、穿刺ステップにおいて穿刺による筋電反応が生じた場合にのみ薬液を投与すると、無駄な薬液投与を回避することができる。すなわち、穿刺したにもかかわらず筋電反応が見られない場合には、別の場所に穿刺し直すことで、筋電反応が生じない箇所への薬液の投与を未然に防止することができる。 Note that wasteful administration of the drug solution can be avoided by administering the drug solution only when a myoelectric reaction due to the puncture occurs in the puncturing step. That is, when the myoelectric reaction is not seen despite the puncture, re-puncturing to another place can prevent administration of the medicinal solution to the place where the myoelectric reaction does not occur.

注射(穿刺及び薬液投与)に伴ってラット12の半腱様筋12bに発生した筋電位は、測定電極24により検出され、高感度生体電気増幅器28により増幅された後に、データ収集装置30に送られる。データ収集装置30によって、筋電位データから筋電位波形が生成される。生成された筋電位波形は、パーソナルコンピュータ32のモニタ画面32aに表示される。 The myoelectric potential generated in the semitendinosus muscle 12b of the rat 12 due to the injection (puncture and administration of drug solution) is detected by the measurement electrode 24, amplified by the high-sensitivity bioelectric amplifier 28, and then sent to the data acquisition device 30. To be The data collection device 30 generates a myoelectric potential waveform from the myoelectric potential data. The generated myoelectric potential waveform is displayed on the monitor screen 32a of the personal computer 32.

図2は、得られる筋電位波形の一例を示している。図2において、T1は注射針18を穿刺した時点であり、穿刺による筋電反応(R1)が見られる。また、T2はラット12への薬液の投与を開始した時点であり、薬液投与による筋電反応(R2)が見られる。 FIG. 2 shows an example of the obtained myoelectric potential waveform. In FIG. 2, T1 is the time point when the injection needle 18 is punctured, and the myoelectric reaction (R1) due to the puncture is seen. Further, T2 is the time when the administration of the drug solution to the rat 12 was started, and the myoelectric reaction (R2) due to the drug solution administration was observed.

上述したように、本発明では、注射針18の穿刺による筋電反応が消えた後に、麻酔されたラット12に注射針18を介して薬液を投与するので、穿刺による筋電反応と薬液投与による筋電反応とが時間的に重ならない。すなわち、薬液投与による筋電反応を、穿刺による筋電反応と分けて測定することができる。 As described above, in the present invention, after the myoelectric reaction due to the puncture of the injection needle 18 disappears, the medicinal solution is administered to the anesthetized rat 12 through the injection needle 18. The myoelectric response does not overlap in time. That is, the myoelectric reaction due to the administration of the drug solution can be measured separately from the myoelectric reaction due to the puncture.

このような筋電位波形が得られたら、薬液投与による痛みを評価(定量化)するために、測定ステップを行う。測定ステップでは、薬液投与による筋電反応の持続時間Tの測定、及び薬液投与による筋電反応が生じてから消えるまでの筋電位の絶対値を積分した積分値S、すなわちEMG強度(μV.s)の測定の少なくとも一方を行う。積分値Sは、筋電反応の持続時間Tの期間における筋電位を整流化し、積分した筋電位波形の面積である。薬液投与による筋電反応の持続時間Tと積分値Sは、パーソナルコンピュータ32により計算してもよいし、データ収集装置30により計算した値をモニタ画面32aに表示させてもよい。 When such a myoelectric potential waveform is obtained, a measurement step is performed in order to evaluate (quantify) the pain caused by administration of the drug solution. In the measuring step, the duration T of the myoelectric reaction due to the administration of the drug solution is measured, and the integrated value S, which is the integral value of the absolute value of the myoelectric potential from the occurrence of the myoelectric response due to the drug solution to its disappearance, that is, EMG intensity (μV.s) ) Make at least one of the measurements. The integrated value S is the area of the myoelectric potential waveform obtained by rectifying and integrating the myoelectric potential during the duration T of the myoelectric reaction. The duration T and the integrated value S of the myoelectric reaction due to the administration of the drug solution may be calculated by the personal computer 32, or the values calculated by the data collecting device 30 may be displayed on the monitor screen 32a.

このように、本発明の方法によれば、注射針18の穿刺による筋電反応が消えた後にラット12に薬液を投与して薬液投与による筋電反応を測定するので、筋電図(EMG)上で穿刺による筋電反応と薬液投与による筋電反応とが重なることがない。これにより、穿刺による痛みと分けて、薬液投与による痛みを評価(定量化)することができる。この場合、穿刺による筋電反応が消えてから1秒以上(より好ましくは10秒以上)経過した後に、薬液の投与を開始すると、穿刺による筋電反応と分けて、薬液投与による筋電反応をより効果的に測定することができる。 As described above, according to the method of the present invention, after the myoelectric reaction due to the puncture of the injection needle 18 disappears, the rat 12 is administered with the drug solution and the myoelectric reaction due to the drug solution administration is measured. The myoelectric reaction due to the puncture and the myoelectric reaction due to the administration of the drug solution do not overlap with each other. This makes it possible to evaluate (quantify) the pain caused by the administration of the drug solution separately from the pain caused by the puncture. In this case, when the administration of the drug solution is started 1 second or more (more preferably 10 seconds or more) after the myoelectric reaction due to the puncture disappeared, the myoelectric reaction due to the drug administration is separated from the myoelectric reaction due to the puncture. It can be measured more effectively.

以上のように組成の異なる複数の薬液毎に、又は複数の投与条件毎に、穿刺ステップ、投与ステップ及び測定ステップを行い、次に、組成の異なる複数の薬液のうち持続時間Tが最も短いあるいは積分値Sが最も小さい薬液組成、又は複数の投与条件のうち持続時間Tが最も短いもしくは積分値Sが最も小さい投与条件を特定する(特定ステップ)。これにより、痛みの少ない薬液組成又は投与条件を選定することができる。 As described above, the puncture step, the administration step and the measurement step are performed for each of a plurality of drug solutions having different compositions, and then the duration T is the shortest among the plurality of drug solutions having a different composition or The chemical solution composition having the smallest integral value S, or the administration condition having the shortest duration T or the smallest integral value S among a plurality of administration conditions is specified (specific step). This makes it possible to select a drug solution composition or administration condition with less pain.

ここで、図3Aは、組成の異なる複数の薬液をラットに注射した場合の各薬液の投与による筋電反応の持続時間を示すグラフである。図3Bは、組成の異なる複数の薬液をラットに注射した場合の各薬液の投与による筋電反応から得たEMG強度を示すグラフである。図3A及び図3Bから、ラットでは薬液組成の違いによって、筋電反応の持続時間及びEMG強度が異なること、すなわち薬液投与による痛みに差があることが分かる。 Here, FIG. 3A is a graph showing the duration of myoelectric reaction due to administration of each drug solution when a plurality of drug solutions having different compositions were injected into a rat. FIG. 3B is a graph showing the EMG intensity obtained from the myoelectric reaction by administration of each drug solution when a plurality of drug solutions having different compositions were injected into a rat. From FIGS. 3A and 3B, it can be seen that in rats, the duration of the myoelectric reaction and the EMG intensity differ depending on the difference in the composition of the drug solution, that is, there is a difference in pain due to the drug solution administration.

図4Aは、生理食塩水を異なる複数の投与量にてヒトに注射した場合の痛みの大きさ(VAS:Visual Analog Scale)を示すグラフである(下部に出典元を示す)。VASは、最大を10として、現在の痛みがどの程度であるかを示す評価スケールである。図4Bは、生理食塩水を異なる複数の投与量にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。図4A及び図4Bから、投与量が増えるほど痛みが大きくなる傾向があることは、ヒトもラットも同じであることが分かる。 FIG. 4A is a graph showing the magnitude of pain (VAS: Visual Analog Scale) when physiological saline is injected into a human at different doses (the source is shown below). VAS is a rating scale showing how much current pain is, with the maximum being 10. FIG. 4B is a graph showing the EMG intensity obtained from the myoelectric reaction by the injection solution when physiological saline was injected into rats at different doses. It can be seen from FIGS. 4A and 4B that the pain tends to increase as the dose increases, in both humans and rats.

図5Aは、異なる複数のpH値でヒトに注射した場合の痛みの大きさ(VAS)を示すグラフである(下部に出典元を示す)。図5Bは、異なる複数のpH値でラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。図5A及び図5Bから、pH値が低いほど痛みが大きくなる傾向があることは、ヒトもラットも同じであることが分かる。 FIG. 5A is a graph showing the pain magnitude (VAS) when injected into humans at different pH values (source is shown below). FIG. 5B is a graph showing the EMG intensity obtained from the myoelectric reaction by the injection solution when injected into rats at different pH values. It can be seen from FIGS. 5A and 5B that the tendency of pain to increase with decreasing pH value is the same in humans and rats.

図6Aは、5%NaClをヒトに注射した場合の痛みの大きさ(VAS)の時間経過を示すグラフである(下部に出典元を示す)。図6Aから、5%NaClをヒトに注射すると、大きな痛みが生じることが分かる。一方、図6Bは、NaClを異なる複数の濃度にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。図6Bから、ラットではNaCl濃度が5%以上で痛みが顕著に大きくなることが分かる。よって、図6A及び図6Bから、NaCl濃度による痛みに関して、ヒトとラットは同様の傾向を示すことが分かる。 FIG. 6A is a graph showing the time course of pain size (VAS) when 5% NaCl was injected into a human (the source is shown in the lower part). From FIG. 6A, it can be seen that injection of 5% NaCl into humans causes great pain. On the other hand, FIG. 6B is a graph showing the EMG intensity obtained from the myoelectric reaction by the injection solution when NaCl was injected into a rat at different concentrations. From FIG. 6B, it can be seen that in the rat, the pain is significantly increased when the NaCl concentration is 5% or more. Therefore, it can be seen from FIGS. 6A and 6B that humans and rats exhibit similar tendencies in pain caused by NaCl concentration.

図7Aは、グルタミン酸を異なる複数のモル濃度にてヒトに注射した場合の痛みの大きさ(VAS)を示すグラフである。なお、図7Aは、同図の下部に示す出典元のグラフに基づいて作成したグラフである。図7Bは、グルタミン酸を異なる複数のモル濃度にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。図7A及び図7Bから、グルタミン酸のモル濃度が高いほど痛みが大きくなる傾向があることは、ヒトもラットも同じであることが分かる。 FIG. 7A is a graph showing pain magnitude (VAS) when glutamic acid is injected into humans at different molar concentrations. Note that FIG. 7A is a graph created based on the graph of the source shown in the lower part of FIG. FIG. 7B is a graph showing the EMG intensity obtained from the myoelectric reaction by the injection solution when glutamic acid was injected into a rat at different molar concentrations. From FIGS. 7A and 7B, it can be seen that the higher the molar concentration of glutamic acid, the greater the tendency for pain to be, which is the same in humans and rats.

以上より、ヒトが感じる痛みの大きさは、ラットを用いた筋電反応の測定結果と同様の傾向を示すことが分かる。また、ラット以外の哺乳類の場合にも、ラットと同様の傾向を示すものと考えられる。よって、本発明の方法は、ヒト用の薬液及び投与方法の開発に適用することができる。 From the above, it is understood that the magnitude of pain felt by humans shows the same tendency as the measurement result of myoelectric reaction using rats. It is also considered that mammals other than rats show the same tendency as that of rats. Therefore, the method of the present invention can be applied to the development of drug solutions and administration methods for humans.

図8Aは、ポリエチレングリコール・生理食塩水混合液を異なる複数の粘度にてラットに注射した場合の注射液による筋電反応の持続時間を示すグラフである。図8Bは、ポリエチレングリコール・生理食塩水混合液を異なる複数の粘度にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。図8A及び図8Bから、注射液の粘度の違いで痛みの大きさが変わることが分かる。 FIG. 8A is a graph showing the duration of myoelectric reaction by an injection solution when a polyethylene glycol/physiological saline mixture solution was injected into a rat at a plurality of different viscosities. FIG. 8B is a graph showing the EMG intensity obtained from the myoelectric reaction by the injection solution when a polyethylene glycol/physiological saline mixture solution was injected into a rat at a plurality of different viscosities. From FIG. 8A and FIG. 8B, it can be seen that the size of pain changes depending on the viscosity of the injection solution.

図9Aは、リン酸緩衝生理食塩水(pH5)を異なる複数の投与速度にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。図9Bは、10%NaClを異なる複数の投与速度にてラットに注射した場合の注射液による筋電反応から得たEMG強度を示すグラフである。図9A及び図9Bから、注射液の組成によっては、注射液の投与速度の違いによって痛みの大きさが変わることが分かる。 FIG. 9A is a graph showing EMG intensity obtained from myoelectric reaction by an injection solution when phosphate-buffered saline (pH 5) was injected into a rat at different administration rates. FIG. 9B is a graph showing the EMG intensity obtained from the myoelectric reaction by the injection solution when 10% NaCl was injected into a rat at different administration rates. From FIGS. 9A and 9B, it can be seen that the magnitude of pain changes depending on the composition of the injection solution and the difference in the injection solution administration rate.

次に、ラット12を用いた薬液投与による痛みの評価について、具体的な実施例を説明する。本実施例においては、以下のように、組成の異なるサンプル1〜3の薬液(炎症性自己免疫疾患治療用の注射用水性製剤)を調整した。 Next, a specific example of the evaluation of pain due to the administration of the drug solution using the rat 12 will be described. In the present example, the drug solutions of Samples 1 to 3 having different compositions (aqueous preparations for injection for treating inflammatory autoimmune disease) were prepared as follows.

(サンプル1)
リン酸水素二ナトリウム(無水)0.71gを注射用水50mLに溶解した。リン酸二水素ナトリウム(無水)0.60gを注射用水50mLに溶解した。リン酸水素二ナトリウム溶液:リン酸二水素ナトリウム溶液=87:13の容量比で混合し、この混合液を注射用水で10倍希釈して10mMリン酸緩衝液とした。メトトレキサート125mg、塩化ナトリウム27mgを10mMリン酸緩衝液5mLに溶解し、水酸化ナトリウム適量にてpHを7.5付近に調整し、メトトレキサート25mg/mL濃度の水溶液を得た。この水溶液を0.2μmの孔径のメンブランフィルターを用いて濾過し、炎症性自己免疫疾患治療用の注射用水性製剤を調製した。
(Sample 1)
0.71 g of disodium hydrogen phosphate (anhydrous) was dissolved in 50 mL of water for injection. 0.60 g of sodium dihydrogen phosphate (anhydrous) was dissolved in 50 mL of water for injection. The disodium hydrogen phosphate solution:sodium dihydrogen phosphate solution was mixed at a volume ratio of 87:13, and this mixed solution was diluted 10 times with water for injection to obtain a 10 mM phosphate buffer solution. 125 mg of methotrexate and 27 mg of sodium chloride were dissolved in 5 mL of 10 mM phosphate buffer, and the pH was adjusted to around 7.5 with an appropriate amount of sodium hydroxide to obtain an aqueous solution having a concentration of 25 mg/mL methotrexate. This aqueous solution was filtered using a membrane filter having a pore size of 0.2 μm to prepare an aqueous injection preparation for treating inflammatory autoimmune disease.

(サンプル2)
サンプル1における水酸化ナトリウムの添加量を変化させた以外は、サンプル1と同様に行い、pH8.0のメトトレキサートを含有する注射用水性製剤を調製した。
(Sample 2)
The same procedure as in Sample 1 was carried out except that the amount of sodium hydroxide added in Sample 1 was changed to prepare an aqueous injectable preparation containing methotrexate at pH 8.0.

(サンプル3)
サンプル1における水酸化ナトリウムの添加量を変化させた以外は、サンプル1と同様に行い、pH8.5のメトトレキサートを含有する注射用水性製剤を調製した。
(Sample 3)
The procedure of Sample 1 was repeated, except that the amount of sodium hydroxide added in Sample 1 was changed, to prepare an aqueous injectable preparation containing methotrexate at pH 8.5.

図1に示した測定システム10を用い、サンプル1〜3のメトトレキサートを含有する注射用水性製剤をラット12に投与したときの筋電図(EMG)を測定した。 Using the measurement system 10 shown in FIG. 1, electromyograms (EMG) were measured when the aqueous injection formulations containing methotrexate of Samples 1 to 3 were administered to rats 12.

具体的には、濃度3%/Airのイソフルランでラット12を麻酔し、半腱様筋12bを露出した。麻酔を1.5%/Air程度に落とし、足先先端にクリップ型刺激電極34を装着した。電気刺激(40Hz、10mA、2ms)を行い、収縮が認められた位置に測定電極24を挿入した。電気刺激強度を5mAに落とし、100μV程度の反応が得られるまで、麻酔濃度を落とした(1〜1.4%/Air)。麻酔濃度を変更してから30分以上安定化させ、ラット12への薬液の投与を行った。 Specifically, rat 12 was anesthetized with isoflurane at a concentration of 3%/Air to expose semitendinosus muscle 12b. Anesthesia was reduced to about 1.5%/Air, and a clip-type stimulation electrode 34 was attached to the tip of the foot. Electrical stimulation (40 Hz, 10 mA, 2 ms) was performed, and the measurement electrode 24 was inserted at the position where contraction was observed. The electric stimulus intensity was lowered to 5 mA, and the anesthetic concentration was lowered until a reaction of about 100 μV was obtained (1 to 1.4%/Air). After the anesthesia concentration was changed and stabilized for 30 minutes or more, the drug solution was administered to the rat 12.

ラット12への薬液の投与においては、シリンジポンプ20に1mLシリンジ14を装てんし、29Gの注射針18を足底皮下12aに穿刺し、10μL/secの投与速度で20μLを投与した。同一の投与条件にてサンプル1〜3を順次ラット12に投与した。EMG強度の測定結果を図10に示す。 In administering the drug solution to the rat 12, the syringe pump 20 was loaded with the 1 mL syringe 14, the 29 G injection needle 18 was punctured into the plantar subcutaneous 12a, and 20 μL was administered at an administration rate of 10 μL/sec. Samples 1 to 3 were sequentially administered to rat 12 under the same administration conditions. The measurement result of the EMG intensity is shown in FIG.

図10から、異なる組成のサンプル1〜3のうち、サンプル1の薬液投与によるEMG強度が最も小さいことが分かった。すなわち、サンプル1の薬液投与による痛みが最も少ないことが分かった。従って、本実施例では、痛みの少ない炎症性自己免疫疾患治療用の注射用水性製剤として、サンプル1の薬液組成を選定することとした。 From FIG. 10, it was found that among samples 1 to 3 having different compositions, sample 1 had the lowest EMG intensity by the administration of the chemical solution. That is, it was found that the pain caused by administration of the chemical solution of Sample 1 was the least. Therefore, in this example, it was decided to select the composition of the drug solution of Sample 1 as an injectable aqueous preparation for treating inflammatory autoimmune diseases with less pain.

上記において、本発明について好適な実施形態を挙げて説明したが、本発明は前記実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲において、種々の改変が可能なことは言うまでもない。 Although the present invention has been described above with reference to the preferred embodiments, it is needless to say that the present invention is not limited to the above embodiments and various modifications can be made without departing from the gist of the present invention. Yes.

10…測定システム 12…ラット
14…シリンジ 18…注射針
20…シリンジポンプ
10... Measuring system 12... Rat 14... Syringe 18... Injection needle 20... Syringe pump

Claims (11)

身体の所定部位と、前記所定部位に刺激を与えた際に脊髄反射によって屈曲する骨格筋とを有する哺乳類の実験動物を準備し、
前記実験動物を吸入麻酔にて麻酔し、
麻酔された前記実験動物の前記骨格筋に測定電極を挿入し、
前記骨格筋の筋電位を前記測定電極で測定しながら、麻酔された前記実験動物の前記所定部位である皮下に注射針を穿刺し、
前記注射針の穿刺による筋電反応が消えてから1秒以上経過した後に、麻酔された前記実験動物の前記皮下への前記注射針を介し薬液投与を開始し、
前記薬液の投与による筋電反応の持続時間の測定、及び前記薬液の投与による前記筋電反応が生じてから消えるまでの前記筋電位の絶対値を積分したEMG強度の測定の少なくとも一方を行うことにより、穿刺による前記筋電反応と分けて、前記薬液の投与による前記筋電反応を測定する
ことを特徴とする薬液投与による痛みの評価方法。
Prepare a mammalian experimental animal having a predetermined part of the body and a skeletal muscle that bends by spinal reflex when the predetermined part is stimulated,
Anesthetizing the experimental animal by inhalation anesthesia,
Inserting a measurement electrode into the skeletal muscle of the anesthetized experimental animal,
While measuring the myoelectric potential of the skeletal muscle with the measurement electrode, puncture an injection needle subcutaneously is the predetermined site of the anesthetized experimental animal,
After 1 second or more has elapsed since the myoelectric reaction due to the puncture of the injection needle disappeared , administration of the drug solution via the injection needle to the subcutaneous of the anesthetized experimental animal was started ,
At least one of the measurement of the duration of the myoelectric reaction due to the administration of the drug solution and the measurement of the EMG intensity obtained by integrating the absolute value of the myoelectric potential from the occurrence of the myoelectric response due to the administration of the drug solution to the disappearance thereof. Therefore, the myoelectric reaction due to the administration of the drug solution is measured separately from the myoelectric reaction due to the puncture .
A method for evaluating pain caused by administration of a drug solution, which comprises:
請求項1記載の薬液投与による痛みの評価方法において、
前記実験動物の前記所定部位の複数の投与箇所に、組成の異なる複数の前記薬液を同じ投与条件で投与し、又は同一組成の前記薬液を異なる投与条件で投与する、
ことを特徴とする薬液投与による痛みの評価方法。
The method for evaluating pain caused by administration of a drug solution according to claim 1,
At a plurality of administration sites of the predetermined site of the experimental animal, a plurality of the drug solutions having different compositions are administered under the same administration conditions, or the drug solutions having the same composition are administered under different administration conditions,
A method for evaluating pain caused by administration of a drug solution, which comprises:
請求項2記載の薬液投与による痛みの評価方法において、
前記実験動物は、ラットである、
ことを特徴とする薬液投与による痛みの評価方法。
The method for evaluating pain caused by administration of a drug solution according to claim 2,
The experimental animal is a rat,
A method for evaluating pain caused by administration of a drug solution, which comprises:
請求項3記載の薬液投与による痛みの評価方法において、
前記所定部位は足底皮下であり、前記骨格筋は半腱様筋である、
ことを特徴とする薬液投与による痛みの評価方法。
The method for evaluating pain caused by administration of a drug solution according to claim 3,
The predetermined site is subcutaneous foot sole, the skeletal muscle is semitendinosus,
A method for evaluating pain caused by administration of a drug solution, which comprises:
請求項3又は4記載の薬液投与による痛みの評価方法において、
前記複数の投与箇所における一箇所当たりの投与量は10〜100μLである、
ことを特徴とする薬液投与による痛みの評価方法。
The method for evaluating pain due to administration of a liquid medicine according to claim 3 or 4,
The dose per site at the plurality of administration sites is 10 to 100 μL,
A method for evaluating pain caused by administration of a drug solution, which comprises:
請求項5記載の薬液投与による痛みの評価方法において、
隣接する前記投与箇所同士の間隔を2mm以上あける、
ことを特徴とする薬液投与による痛みの評価方法。
The method for evaluating pain caused by administration of a medical solution according to claim 5,
A space of 2 mm or more is provided between adjacent administration points,
A method for evaluating pain caused by administration of a drug solution, which comprises:
請求項3〜6のいずれか1項に記載の薬液投与による痛みの評価方法において、
前記複数の投与箇所での総投与量は200μL以下である、
ことを特徴とする薬液投与による痛みの評価方法。
The method for evaluating pain due to administration of a liquid medicine according to claim 3,
The total dose at the plurality of administration sites is 200 μL or less,
A method for evaluating pain caused by administration of a drug solution, which comprises:
請求項3〜7のいずれか1項に記載の薬液投与による痛みの評価方法において、
前記薬液の投与速度は5〜100μL/secである、
ことを特徴とする薬液投与による痛みの評価方法。
The method for evaluating pain caused by administration of the drug solution according to any one of claims 3 to 7,
The administration rate of the drug solution is 5 to 100 μL/sec,
A method for evaluating pain caused by administration of a drug solution, which comprises:
請求項1〜のいずれか1項に記載の薬液投与による痛みの評価方法において、
前記穿刺による前記筋電反応が生じた場合にのみ前記薬液を投与する、
ことを特徴とする薬液投与による痛みの評価方法。
In the evaluation method of pain with a chemical solution administration according to any one of claims 1-8,
The drug solution is administered only when the myoelectric reaction due to the puncture occurs.
A method for evaluating pain caused by administration of a drug solution, which comprises:
請求項1〜のいずれか1項に記載の薬液投与による痛みの評価方法において、
前記測定電極として双極電極を用い、前記実験動物の胸部皮膚に基準電極を貼付する、
ことを特徴とする薬液投与による痛みの評価方法。
In the evaluation method of pain with a chemical solution administration according to any one of claims 1 to 9
Using a bipolar electrode as the measurement electrode, a reference electrode is attached to the chest skin of the experimental animal,
A method for evaluating pain caused by administration of a drug solution, which comprises:
身体の所定部位と、前記所定部位に刺激を与えた際に脊髄反射によって屈曲する骨格筋とを有する哺乳類の実験動物を準備する準備ステップと、
前記実験動物を吸入麻酔にて麻酔する麻酔ステップと、
麻酔された前記実験動物の前記骨格筋に測定電極を留置する測定電極留置ステップと、
前記骨格筋の筋電位を前記測定電極で測定しながら、麻酔された前記実験動物の前記所定部位である皮下に注射針を穿刺する穿刺ステップと、
前記注射針の穿刺による筋電反応が消えてから1秒以上経過した後に、麻酔された前記実験動物の前記皮下への前記注射針を介し薬液投与を開始する投与ステップと、
前記薬液の投与による筋電反応が生じてから消えるまでの前記筋電位の絶対値を積分したEMG強度の測定、及び前記薬液の投与による前記筋電反応の持続時間の測定の少なくとも一方を行うことにより、穿刺による前記筋電反応と分けて、前記薬液の投与による前記筋電反応を測定する測定ステップと、を含み、
組成の異なる複数の薬液毎に、又は複数の投与条件毎に、前記穿刺ステップ、前記投与ステップ及び前記測定ステップを行い、
さらに、組成の異なる前記複数の薬液のうち、前記持続時間が最も短い、あるいは前記EMG強度が最も小さい薬液組成、又は前記複数の投与条件のうち、前記持続時間が最も短い、あるいは前記EMG強度が最も小さい投与条件を特定する特定ステップを含む、
ことを特徴とする薬液投与の選定方法。
A preparatory step of preparing a mammalian experimental animal having a predetermined part of the body and a skeletal muscle that bends by spinal reflex when the predetermined part is stimulated,
Anesthesia step of anesthetizing the experimental animal by inhalation anesthesia,
Measuring electrode placement step of placing a measurement electrode in the skeletal muscle of the anesthetized experimental animal,
While measuring the myoelectric potential of the skeletal muscle with the measurement electrode, a puncturing step of puncturing an injection needle under the skin which is the predetermined site of the anesthetized experimental animal,
A dosing step of myoelectric reaction by puncture of the injection needle after more than one second off, to start doses of the liquid medicine through the needle into the subcutaneous anesthetized said experimental animal,
Performing at least one of the muscle measuring the integral of EMG intensity absolute value of the potential, and the measurement of the duration of the myoelectric reaction by the administration of the drug solution to disappear from the EMG reaction occurs by administration of the chemical According to the method, a step of measuring the myoelectric reaction due to administration of the drug solution is provided, which is separate from the myoelectric reaction due to puncture .
For each of a plurality of drug solutions having different compositions, or for each of a plurality of administration conditions, performing the puncturing step, the administering step and the measuring step,
Further, among the plurality of drug solutions having different compositions, the duration is the shortest, or the drug solution composition having the smallest EMG intensity, or the plurality of administration conditions, the duration is the shortest or the EMG intensity is Including specific steps to identify the smallest dosing conditions,
A method for selecting a drug solution, which is characterized by the following.
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