EXPANSION RESEARCH FOR DEVELOPMENT OF LOCAL ANESTHETIC HAVING ANTI INFLAMMATORY ACTION

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1 No. 137 EXPANSION RESEARCH FOR DEVELOPMENT OF LOCAL ANESTHETIC HAVING ANTI INFLAMMATORY ACTION Takuya MIYAWAKI Professor Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Okayama University Outline The present research is being conducted to further improve the evaluation of our invention to be supported by JST for which a Japanese patent has already been applied in order to apply for 5 overseas patents in the USA, Germany, Italy, France, UK and China, and which was supported by JST for a PCT patent. The invention thereof uses the fact that by adding an α2 adrenergic receptor agonist to a local anesthetic, the effect of the local anesthetic may be prolonged and a local anesthetic composition having higher safety may be made. Furthermore, an object of the present examination and research is to verify an anti-inflammatory action of this α2 adrenergic receptor agonist itself. By adding the α2 adrenergic receptor agonist into the local anesthetic, pain and swelling due to surgery can be relieved by the anti-inflammatory action and the effect of speeding recovery from treatment is expected. Technical Field of the Research Medical agent 1. Advantage of the developed technology The present research is being conducted in order to improve the value of a local anesthetic composition which is already patent pending. The local anesthetic is used in a dental therapy, surgical procedures and in pain clinics; however, from a viewpoint of controlling pain, it has been developed while focusing on obtaining a stronger anesthetic effect, a longer acting period and fewer side effects. However, after administrating the local anesthetic, an invasive procedure such as a surgery may be performed and when the effect of the local anesthetic disappears(after several hours at most), a patient may suffer from pain or swelling. In the present examination and research, we note the anti-inflammatory action of the α2 adrenergic receptor agonist (hereinafter, referred to as α2 receptor agonist)which is a substance added to the local anesthetic composition for which our patent is pending and an aim thereof is to provide the antiinflammatory action to the local anesthetic. By developing the local anesthetic having the antiinflammatory action, it is possible to suppress reactions(pain or swelling)due to the

2 inflammation which occurs along with invasive procedures, reduce the pain of the patient and further, an early recovery after the surgery may be expected. Indeed, it will be an innovative development in a field of the local anesthetic. As far as we know, there are no inventions regarding this yet, in Japan or abroad. In this regard, if we advance the research as quickly as possible, we can get a big lead over our academic rivals. 2. Marketability and Potential of the Technology Since speeding recovery after surgery means promoting early discharge of the patient from the hospital, it is an important issue for medical economics. Since there is a tendency to convert as much as possible from major surgery which needs general anesthetic towards surgery which is less invasive, so-called minimally invasive surgery is a great global aim in surgical fields. With these developments, some surgeries which have been performed using a general anesthetic will be performed using a local anesthetic and the demand for local anesthetics is expected to increase. It is reported that long term prognosis(mortality rate)after surgery is worsened due to the excessive general anesthetic use, an invasive procedure with respect to the body and overdose administration of the general anesthetic. From this viewpoint, the marketability of local anesthetics seems set to expand in the future. Furthermore, when the early recovery after the surgery is focused upon as an objective, because anti-inflammatory action will help with this greatly, it is expected that anti-inflammatory therapy will be increasingly developed in the future. However, if it is possible to provide the anti-inflammatory action along with the local anesthetic, anti-inflammatory action can be easily realized by administrating the local anesthetic, increasing its utility value so that yet more important marketability can be expected. 3. Object and Demand An objective of the present study is to verify the anti-inflammatory action which is due to α2 receptor agonist, that is added to the local anesthetic composition which is already patent pending and which is a basis for the present research. We have already verified that there is an antiedematous effect in the α2 receptor agonist through an animal test(fig. 1)

3 Fig. 1 On the basis of a test result using a mouse footpad swelling assay, Fig. 1 shows time dependent changes of inflammatory swelling(increase in footpad volume)which are caused by Carrageenin which is a prophlogistic substance. Fig. 1 shows the antiedematous effect of the α2 receptor agonist(dexmedetomidine)with respect to the inflammatory swelling due to the Carrageenin. The inflammatory reaction such as swelling or the like is amplified through a mediator of inflammation which is generated in a tissue due to the prophlogistic substance, injuries or the like. In order to explain the action mechanism of the antiedematous effect of the α2 receptor agonist, it is necessary to observe the movement of the mediator of inflammation. In this regard, a specific object of the present examination and research is to investigate the influence of the α2 receptor agonist with respect to the generation of the mediator of inflammation. 4. Planned Activities (1)Samples 1)Target animal: eight-week-old-male ICR mouse 2) Local inflammatory model: Noninfectious local inflammatory model: administer 5% Carrageenin as a prophlogistic substance 3)Stimulus site: inject subcutaneously in a rear foot paw 4) Administration of α2 receptor agonist(dexmedetomidine): local administration(mix with a prophlogistic substance) 5) Evaluation of an instance of inflammation: measure the swelling rate of the inflammatory swelling cause by the prophlogistic substance which is injected to the rear foot of the mouse along with the time lapse using a swelling volume measuring device. 6) Preparation of sample: After performing the evaluation of the inflammation, the stimulus site of the target animal is removed, the sample of the removed site is divided for immunohistochemical evaluation and for gene expression evaluation. Sequentially, the divided samples are fixed in separate preservative solutions and are immediately frozen and preserved at minus 80 by an ultra deep freezer

4 (2)Chemical evaluation of immune tissue 1) Processing of samples and HE dyeing: the samples are immersed and fixed for one night in a fixing solution of 10% formalin and are permeated by a paraffin permeating device to form a paraffin block. Using a dedicated rotary microtome, the block is sliced to have a thickness of 5µm HE dyeing is performed, and the slice is observed. 2) First antibody response: After blocking the cells by 0.5% saponin and 3% BSA, the primary antibody with respect to a target inflammatory mediator(tnf-α, IL-1β, COX2), Alexa Flour 568(Molecular Probes)red, and F-actin green for verifying cell cytoskeleton are used. 3)Secondary antibody response: Histofine simple stain is used. 4) Observation of fluorescence stain: After the coloring(brown)due to DAB coloring, nuclear staining is performed with hematoxylin and it is observed by confocal scanning laser microscopy. (3)Gene expression evaluation 1) Adjustment of sample: The sample which is preserved at minus 80 has RNA extracted and purified using a cooled microcentrifuge, a centrifuge rotor and RNA extraction kit, a Dnase treatment is performed, reverse transcription is performed using an RT kit, and a cdna library of each mediator is manufactured. 2) Quantitative evaluation of mrna by real-time polymerase chain reaction(rt-pcr): Capillary, primer for each mediator and MgCl2 are added to the manufactured cdna library. The temperature for the real-time PCR analysis system and annealing is set to be 68, the real-time PCR is performed over 40 cycles, and the mediator gene(mrna) expression quantity is determined, using β-actin as an internal reference. 5. Aim An aim of the present research is to verify whether the generation of these mediators of the inflammation are suppressed by locally administrating the α2 receptor agonist, testing with inflammatory cytokine(tnf α, IL-1β)and COX2(cyclooxygenase-2)as representative mediators of inflammation. By doing so, it is possible to prove that the anti inflammatory action of the α2 receptor agonist is not a simple phenomenon and the action mechanism can be proved as well, thereby raising the reliability of α

5 6. Patent 1 Title of the Patent local anesthetic composition Application No. PCT/JP2009/ Application date October 30, 2008 Applicant Okayama University Inventor Takuya MIYAWAKI, Tatsushi YOSHITOMI Outline It was found that by adding an α2 adrenergic receptor agonist to a local anesthetic in which adrenalin or salt thereof is included, the content of the adrenalin or the salt thereof can be reduced and a local anesthetic composition having a high safety is obtained. Contact Person Name Kenich YOSHIDA yoshidak@cc.okayama-u.ac.jp Name of department Intellectual Property Office of Organization For Research Promotion & Collaboration of OKAYAMA University Position Manager of Intellectual Property Office