Composition for protecting wood from marine wood borers

Abstract

Embodiments of the present invention relate to a method of reducing or preventing infestation of marine wood-boring insects to wood in a marine environment by impregnating the wood with a composition comprising medetomidine or an enantiomer, salt or base thereof.

Description

Technical Field

[0001] Embodiments herein are generally directed to a method of impregnating wood with a composition for the purpose of preventing or at least reducing wood-boring insect attack on the wood in a marine environment. Background Art

[0002] Wood in marine environments is attacked by various wood-boring insects, including but not limited to shipworms and water lice. Wood-boring insects bore into the wood and dig tunnels into the wood. Wood-boring insect infestations usually appear as small holes on the surface, but inside, the larvae dig larger and larger burrows as they grow. The larvae coat the inside of the wood with calcium material. An adult shipworm can be up to 60 cm long and 1 cm in diameter. These infestations by wood-boring insects destroy the structural integrity of the wood and the structures made from it. After an infestation, it can take only a few months for the wood to be completely destroyed and need to be replaced.

[0003] In the eighteenth century, copper sheathing was used on wooden ships as a means of preventing damage by marine wood borers. In addition, it was discovered that chemicals such as creosote or compositions such as chromated copper arsenate (CCA) could be used to impregnate wood and protect it from wood borers. Concerns about the effects of these treatments on non-target organisms have led to legislation in many countries (European Commission, 2003) and these well-established and generally effective marine wood preservatives are now restricted or banned.

[0004] WO2013 / 131940 discloses a method for reducing or preventing marine wood borers from infesting wood in a marine environment by impregnating the wood with a biocidal composition comprising tralopyril. However, tralopyril may be embryotoxic, have teratogenic potential in aquatic animals, and may cause thyroid endocrine disorders (Ecotoxicology and Environmental Safety (2021) 223: 112615).

[0005] WO2013 / 141821 discloses an anti-marine wood-boring insect composition comprising a group of base polymers for exposure to a liquid environment (wherein the presence of marine wood-boring insects is expected) and a phthalocyanine compound.

[0006] JP2018-080275 discloses an antifouling coating composition containing a polyether-modified silicone oil, an antifouling agent and a film-forming resin.

[0007] EP2432315 discloses the preparation of small polymer microcapsules with an oil core and solid microspheres containing a large amount of biocide by internal phase separation from emulsion droplets using ethyl acetate as solvent. The size of the microcapsules and microspheres is between 0.2-20 μm in diameter.

[0008] There remains a need for treatment of wooden structures exposed to marine environments to prevent or at least reduce infestation by marine wood-boring insects. Summary of the invention

[0009] A general objective of the present disclosure is to protect wooden structures exposed to marine environments from marine wood-boring insects such as shipworms and water lice.

[0010] The embodiments disclosed herein achieve this and other objectives.

[0011] The invention is defined in the independent claim. Further embodiments of the invention are defined in the dependent claims.

[0012] One aspect of the embodiment relates to a method of reducing or preventing attack by marine wood-boring insects on wood present in a marine environment. The method comprises impregnating at least a portion of the wood with a composition comprising medetomidine or an enantiomer, salt or base thereof in an amount of at least 0.05% by weight, based on the total weight of the composition.

[0013] Another aspect of the embodiment relates to the use of a composition comprising medetomidine or an enantiomer, salt or base thereof in an amount of at least 0.05% by weight, based on the total weight of the composition, for reducing or preventing attack by marine wood-boring insects on wood present in a marine environment.

[0014] The medetomidine composition of the present invention is capable of protecting wood in marine environments, such as piles, bridge piers, hulls and similar structures, from wood-boring insects such as shipworms and water lice. The medetomidine composition is also safe for workers to operate and the environment from the perspective of health, safety and environment (HSE) in the intended use. The medetomidine composition is also capable of penetrating into the wood so that a sufficient amount of medetomidine or its enantiomer, salt or base is absorbed by the wood to ensure a long-lasting protective effect.

[0015] Brief Description of Figures and Tables

[0016] The embodiments and further objects and advantages thereof may best be understood by reference to the following description taken in conjunction with the accompanying drawings and tables, in which:

[0017] Figure 1 Treated and untreated wooden test pieces after one year of immersion are shown. The upper left corner is an untreated reference wooden test piece. The remaining wooden test pieces have been treated with a 0.8% ethanol solution prepared from a concentrate of medetomidine in 1-methoxy-2-propanol (20%) as described in Example 1.

[0018] Figure 2The wooden test pieces after one year of immersion are shown. First column: reference wooden test pieces treated with chromated copper arsenate (CCA), second column: untreated reference wooden test pieces, third column: wooden test pieces treated with solution A (0.1%), fourth column: wooden test pieces treated with solution B (0.5%), fifth column: wooden test pieces treated with solution C (1.0%). Solutions A, B and C were prepared by diluting a concentrate consisting of 10 parts of medetomidine, 9 parts of acetic acid and 9 parts of water, as described in Example 1. DETAILED DESCRIPTION

[0019] The foregoing and other aspects of the embodiments will now be described in more detail in conjunction with the description and methods provided herein. It should be understood that the present invention can be embodied in different forms and should not be construed as being limited to the embodiments described herein. On the contrary, these embodiments are provided to make this disclosure comprehensive and complete and to fully convey the scope of the present invention to those of ordinary skill in the art.

[0020] Those skilled in the art will understand that the terms used in the description herein are only used to describe specific embodiments and are not intended to limit the present invention. Unless otherwise defined, all terms (including technical and scientific terms used in the specification) have the same meaning as those generally understood by those skilled in the art to which the present invention belongs.

[0021] As used in the description of the embodiment, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are also intended to include plural forms. Therefore, these references can be replaced with references to "one or more (one or more)" (e.g., one) of the relevant components or integers. As used herein, all references to "one or more" of a particular component or integer should be understood to refer to such components or integers from one to multiple (e.g., two, three or four). It should be understood that references to "one or more" of a particular component or integer will include specific references to one such integer. In addition, as used herein, "and / or" refers to and encompasses any and all possible combinations of one or more related listed items. In addition, the term "about" used herein refers to a change of 20%, 10%, 5%, 1%, 0.5% or even 0.1% of a specified amount when referring to a measurable value (e.g., the amount of a compound, dosage, time, temperature, etc.). When a range is used, such as a range from x to y, this means that a measurable value is a range from about x to about y, or any range or value including x and y. It should be further understood that when the terms “include” and / or “comprising” are used in this specification, they specify the presence of stated features, integers, steps, operations, elements, components and / or groups, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups.

[0022] All patents, patent applications, and publications cited herein are incorporated herein by reference in their entirety. In the event of a conflict in terminology, the present specification controls.

[0023] As used herein, "wood" encompasses all forms of wood, including but not limited to solid wood, such as timber or lumber, such as logs, beams, planks, sheets and boards, wood composite materials, such as plywood, laminated lumber or wood plastic composites, and all products made from wood and wood composite materials. Exemplary but non-limiting examples of such wood products include ship hulls, harbor installations, dry docks, piers, sluice gates, locks, mooring masts, wooden poles, bridges, bulkheads, etc.

[0024] As used herein, "woodborer" refers to marine woodborers that are either molluscs or crustaceans. Woodborer molluscs include bivalve molluscs of the family Pholadidae, also known as piddocks or angelwings, and bivalve molluscs of the family Teredinidae, also known as shipworms. Woodborer crustaceans include marine isopods from the family Limnoriidae, also known as gribble; woodlice from the family Armadillidiidae, also known as pill bugs or roly polies; and amphipods of the family Cheluridae. Particularly common marine wood-boring insects include Teredo navalis, commonly known as the naval shipworm or turu, and Limnoria lignorum, commonly known as the water louse.

[0025] The present embodiments generally relate to a method of impregnating wood with a composition for the purpose of preventing or at least reducing attack by wood-boring insects on the wood in a marine environment.

[0026] It has been found that impregnation of wood with a medetomidine composition prior to immersing the wood in a marine environment can prevent or at least reduce attack by marine wood-boring insects on wood in a marine environment.

[0027] Thus, one aspect of the embodiment relates to a method of reducing or preventing marine wood-boring insects from attacking wood present in a marine environment. The method comprises impregnating at least a portion of the wood with a composition comprising medetomidine or an enantiomer, salt or base thereof in an amount of at least 0.05% by weight, based on the total weight of the composition.

[0028] Medetomidine, also known as (±)-4-[1-(2,3-dimethylphenyl)ethyl)-1H-imidazole, see formula I, is a highly selective α2-adrenoceptor agonist. The imidazole group of medetomidine has two tautomers, corresponding to 4-[1-(2,3-dimethylphenyl)ethyl)-1H-imidazole or its tautomer 5-[1-(2,3-dimethylphenyl)ethyl)-1H-imidazole shown in formula I.

[0029]

[0030] Medetomidine is a racemic mixture of two optical enantiomers, i.e., left-handed and right-handed optical isomers (Journal of pharmacology and experimental therapeutics (1991) 259: 848-854; European Journal of Pharmacology (1991) 195: 193-199), with common names of levo-medetomidine and dexmedetomidine, respectively. Methods for preparing medetomidine and related intermediates are disclosed in, for example, WO2011 / 070069 and WO2013 / 014428.

[0031] Unless otherwise expressly stated, the terms medetomidine, dexmedetomidine and levomedetomidine as used herein include salts, bases and solvates thereof. The acceptable salts of medetomidine, dexmedetomidine and levomedetomidine include acid addition salts and base addition salts. Such salts can be formed by conventional methods, for example, by reacting medetomidine, dexmedetomidine and levomedetomidine in the form of free acid or free base with one or more equivalents of appropriate acid or base, optionally in a solvent, or in a medium in which the salt is not dissolved, and then removing the solvent or medium using standard techniques (e.g., vacuum or freeze drying). Salts can also be prepared by exchanging the counterions of medetomidine, dexmedetomidine and levomedetomidine in the form of salts with another counterion, for example, using a suitable ion exchange resin. An illustrative but non-limiting example of a salt of medetomidine is medetomidine hydrochloride. For the avoidance of doubt, other acceptable derivatives of medetomidine, dexmedetomidine and levomedetomidine are also included within the scope of the present invention, such as solvates and the like.

[0032] The enantiomers of medetomidine can be separated from each other by separating the racemic or other mixtures of enantiomers using chiral resolution or chiral column chromatography as known in the art. Alternatively, the desired enantiomer can be prepared by enantioselective synthesis, also known as chiral synthesis or asymmetric synthesis, which is defined as a chemical reaction or reaction sequence in which one or more new chiral elements are formed in a substrate molecule to produce unequal amounts of stereoisomeric products.

[0033] Medetomidine in its base form is marketed by I-Tech AB under the product name Sale.

[0034] As used herein, a "medetomidine composition" or "medetomidine solution" includes a composition or solution comprising medetomidine or an enantiomer, salt or base thereof.

[0035] Below, various aspects and embodiments of the present invention will be described in more detail for medetomidine.These aspects and embodiments also include the enantiomer of medetomidine, such as dexmedetomidine and levomedetomidine, the salt of medetomidine, the salt of dexmedetomidine or the salt of levomedetomidine or the alkali of medetomidine, the alkali of dexmedetomidine or the alkali of levomedetomidine, collectively referred to as medetomidine, or its enantiomer, alkali or salt.Therefore, unless otherwise indicated, otherwise mentioning medetomidine herein should be deemed to relate to medetomidine, the salt of medetomidine, the alkali of medetomidine, dexmedetomidine, the salt of dexmedetomidine, the alkali of dexmedetomidine, levomedetomidine, the salt of levomedetomidine and / or the alkali of levomedetomidine.

[0036] According to embodiments, the use of a medetomidine composition (e.g., a medetomidine solution) can prevent, inhibit, stop or significantly delay the invasion, infestation or penetration of one or more types of marine wood-boring insects (e.g., wood-boring bivalve molluscs and crustaceans) for at least 3 months, or even longer, such as several months, such as 6-9 months, or one or more years, such as 1-10 years, or 2-5 years. According to embodiments, the use of a medetomidine composition (e.g., a medetomidine solution) impregnated on a surface and / or in a marine environment exposed or exposed to marine wood-boring insects or impregnated on a surface and / or in a material, structure or object (collectively referred to herein as wood or wood products) at risk of marine wood-boring insects can prevent, inhibit, stop or significantly delay the invasion, infestation or penetration of marine wood-boring insects into such surfaces during a corresponding period of time or service or service life.

[0037] Thus, impregnation of wood with a medetomidine composition (eg, a medetomidine solution) according to embodiments will render the wood material, structure, or object made therefrom resistant to attack by marine wood borers.

[0038] In one embodiment, the composition comprises medetomidine or its enantiomer, salt or base in an amount of 0.05% to 5% by weight based on the total weight of the composition. In a preferred embodiment, the composition comprises medetomidine or its enantiomer, salt or base in an amount of 0.1% to 5% by weight based on the total weight of the composition, preferably in an amount of 0.1% to 2.5% by weight based on the total weight of the composition. More preferably, the composition comprises medetomidine or its enantiomer, salt or base in an amount of 0.5% to 2.5% by weight based on the total weight of the composition, preferably in an amount of 0.5% to 1.0% by weight based on the total weight of the composition.

[0039] In one embodiment, the composition is a solution comprising medetomidine or an enantiomer, salt or base thereof. Thus, in such an embodiment, the medetomidine composition is a medetomidine solution comprising medetomidine or an enantiomer, base or salt thereof dissolved or dispersed in a solvent.

[0040] In one embodiment, the solvent is selected from water, carboxylic acids, alcohols and any combination thereof. Currently preferred carboxylic acids include formic acid (formic acid), acetic acid (acetic acid), propionic acid and butyric acid, more preferably acetic acid, i.e. acetic acid. Currently preferred alcohols include methanol, ethanol, propan-2-ol, butan-1-ol, ethylene-1,2-diol, propan-1,2-diol, butan-1,2-diol, propan-1,3-diol, butan-1,3-diol, butan-1,4-diol, benzyl alcohol and 1-methoxypropan-2-ol (propylene glycol methyl ether (PGME) or 1-methoxy-2-propanol).

[0041] In certain embodiments, the solvent is selected from water, acetic acid, methanol, ethanol, butane-1,4-diol, benzyl alcohol, 1-methoxypropan-2-ol, or any combination thereof.

[0042] The solubility of medetomidine in water depends on pH and temperature, with higher solubility at low pH and higher temperatures and lower solubility at higher pH and lower temperatures.

[0043] In one embodiment, the solution is an acidic aqueous solution comprising medetomidine or its enantiomer, salt or base. The acidic aqueous solution then has an acidic pH, i.e. a pH below 7. In a preferred embodiment, the pH of the acidic aqueous solution is selected in the interval of 4 to 6, more preferably in the interval of 4.5 to 5.5. The currently preferred pH of the acidic aqueous solution is 4.6 to 5.4, 4.7 to 5.3, 4.8 to 5.2, or 4.9 to 5.1, for example about 5.0.

[0044] It is preferred that the acidic aqueous solution used to impregnate the wood or at least a portion of the wood has a pH of about 5 in order to be compatible with the wood. Too large a difference in pH between the wood and the acidic aqueous solution may result in precipitation of medetomidine or its enantiomer, salt or base in the acidic aqueous solution, thereby resulting in less penetration of medetomidine or its enantiomer, salt or base into the wood during the impregnation process.

[0045] The acidic aqueous solution is preferably in the form of a mixture of at least one acid and water, in particular a mixture of at least one carboxylic acid and water, such as a mixture of acetic acid and water.

[0046] For example, a concentrated acidic aqueous solution can be prepared by dissolving medetomidine (10 parts) in concentrated acetic acid (9 parts) and water (9 parts) at room temperature. The resulting concentrated acidic aqueous solution is then diluted to an appropriate use solution by adding water.

[0047] In one embodiment, the method includes dissolving medetomidine or its enantiomer, salt or alkali in an acidic aqueous solvent to form a concentrated acidic aqueous solution with a first pH. In a specific embodiment, the concentrated acidic aqueous solution is a mixture of at least one acid (preferably at least one carboxylic acid, more preferably acetic acid) and water. The method then includes diluting the concentrated acidic aqueous solution with water to form an acidic solution with a second pH. The first pH is lower than the second pH, and the second pH is lower than 7, preferably selected in the interval of 4 to 6, more preferably selected in the interval of 4.5 to 5.5, for example, about 5.0.

[0048] Medetomidine solutions are generally easier to prepare in organic solvents (e.g., alcohols), but are accompanied by additional disadvantages associated with such organic solvents, such as in terms of worker safety and flammability issues. Illustrative but non-limiting examples of suitable organic solvents are methanol, ethanol, butane-1,4-diol, benzyl alcohol, 1-methoxypropan-2-ol. For example, a concentrate of medetomidine or its enantiomer, salt, or base may first be prepared in an organic solvent. The concentrate may then be diluted with a suitable solvent (e.g., an organic solvent and / or water) for impregnation.

[0049] In one embodiment, impregnating at least a portion of the wood comprises impregnating at least a portion of a wood product with a medetomidine composition (e.g., a medetomidine solution). A wood product is a product made of wood, or at least comprises wood, and wherein the wood product or at least one or more wooden parts of the wood product are to be at least partially immersed in a marine environment. In a specific embodiment, at least a portion of at least one wooden surface of the wood product is impregnated with a medetomidine composition, such as a medetomidine solution.

[0050] As previously mentioned, the method comprises impregnating at least a portion of the wood with a medetomidine composition (e.g., a medetomidine solution). In one embodiment, only a portion of the wood is impregnated with a medetomidine composition (e.g., a medetomidine solution). For example, only a portion of the wood product may be exposed to the marine environment and may therefore be subject to the infringement of marine wood-boring insects. For example, any remainder of the wood product may be present outside the water, i.e., not immersed in water during use. Alternatively, the remainder of the wood product may be protected by a surface coating, a sheet or a layer to prevent marine wood-boring insects from reaching the wood below. In such an embodiment, only the wood portion that is exposed to and susceptible to the infringement of marine wood-boring insects is impregnated with a medetomidine composition (e.g., a medetomidine solution).

[0051] In another embodiment, the method comprises impregnating the wood with a medetomidine composition (e.g., a medetomidine solution). In this embodiment, the entire or at least substantially the entire wood product is impregnated with a medetomidine composition, e.g., a medetomidine solution. This means that all surfaces of the wood product are preferably impregnated to protect these surfaces and the wood from marine wood borers when the wood product is immersed in a marine environment.

[0052] At least a portion of the wood can be impregnated with a medetomidine composition (eg, a medetomidine solution) according to various embodiments. In one embodiment, at least a portion of the wood is impregnated with a medetomidine composition (eg, a medetomidine solution) in a closed, high pressure system.

[0053] In this embodiment, the wood or at least the portion thereof to be treated with the medetomidine composition is exposed to high pressure when in contact with the medetomidine composition (e.g., medetomidine solution). High pressure as used herein means a pressure above ambient pressure, i.e., above 1 bar. In a particular embodiment, during the impregnation, the wood is exposed to a pressure of at least 2 bars, e.g., at least 3 bars, at least 4 bars, or at least 5 bars, or even higher pressures, e.g., at least 6 bars, at least 7 bars, at least 8 bars, at least 9 bars, or at least 10 bars. In this embodiment, even higher pressures may also be used.

[0054] An example of a closed high pressure system is the "full-cell process", also known as the "Bethell process", which is a method of impregnating wood with a preservative, invented by American inventor John Bethell in the 19th century. It involves sealing the wood in a pressure chamber and applying a vacuum to remove air and moisture from the wood cells. The wood is then pressure treated with a preservative to impregnate the wood whole cell (i.e., the cell wall and the lumen or interior) with a substance that imparts properties such as resistance to decay, fire, insects, and wood-boring marine animals. According to an embodiment, this Bethell process can be used to impregnate at least a portion of the wood with a medetomidine composition (e.g., a medetomidine solution).

[0055] Another example of a closed high pressure system is the so-called "Rüping process", in which the wood is placed in a pressurized impregnation boiler, then the medetomidine composition (eg, a medetomidine solution) is introduced and the pressure is released.

[0056] In another embodiment, at least a portion of the wood is impregnated with a medetomidine composition (e.g., a medetomidine solution) in a vacuum system. Thus, in this embodiment, at least a portion of the wood is impregnated with a medetomidine composition (e.g., a medetomidine solution) under vacuum. As used herein, vacuum refers to a pressure below ambient pressure, such as equal to or below 500 mbar, equal to or below 100 mbar, equal to or below 10 mbar, equal to or below 1 mbar, or even lower.

[0057] In another embodiment, at least a portion of the wood is impregnated with a medetomidine composition (e.g., a medetomidine solution) while applying an oscillating pressure or a series of vacuum cycles. In the former case, the wood can be exposed to alternating pressures during impregnation, such as X1 bar, X2 bar, X1 bar, X2 bar, etc., where X1 > X2 or X1 < X2. For example, one of X1 and X2 can be 1 bar, i.e., ambient pressure, while the other of X1 and X2 is a pressure above ambient pressure. In the case of a series of vacuum cycles, a similar method can be applied by alternating between reducing the pressure below ambient pressure, having the pressure equal to or above ambient pressure, reducing the pressure below ambient pressure, having the pressure equal to or above ambient pressure, etc.

[0058] A further embodiment of impregnating at least a portion of the wood is to immerse or soak at least a portion of the wood in a medetomidine composition (e.g., a medetomidine solution). Other techniques for impregnating at least a portion of the wood can also be used, such as by applying a medetomidine composition (e.g., a medetomidine solution), by painting at least a portion of the wood with a medetomidine composition (e.g., a medetomidine solution), or by brush application.

[0059] Examples

[0060] Example 1 - Impregnation Solution

[0061] Solvent-based Impregnation Solution

[0062] Medetomidine (200 g, I-Tech AB) was dissolved in 1-methoxy-2-propanol to form a 1-liter solution. This medetomidine solution was diluted with ethanol to a final concentration of 0.8 wt% medetomidine and used as the impregnation solution.

[0063] Water-based Impregnation Solution

[0064] Medetomidine has poor water solubility. To increase the solubility, the imidazole ring in medetomidine was protonated using acetic acid.

[0065] 0.1% Solution A

[0066] 5g of medetomidine ( I-Tech AB), 4.5 g acetic acid and 4.5 g water were mixed in a 100 ml E-flask and stirred. A clear solution was obtained after 60 minutes. The solution was diluted with water to a final weight of 5 kg.

[0067] 0.5% solution B

[0068] 25 g of medetomidine ( I-Tech AB), 22.5 g of acetic acid and 22.5 g of water were mixed in a 100 ml E-flask and stirred. A clear solution was obtained after 60 minutes. The solution was diluted with water to a final weight of 5 kg.

[0069] 1.0% Solution C

[0070] 50 g of medetomidine ( I-Tech AB), 45 g of acetic acid and 45 g of water were mixed in a 250 ml flask and stirred. A clear solution was obtained after 30 minutes. The solution was diluted with water to a final weight of 5 kg.

[0071] Example 2

[0072] Impregnation with solvent-based solutions

[0073] A wooden test piece (EN 252, pine, 25×50×150 mm) was prepared. The wooden test piece was whole cell impregnated with the 0.8% 1-methoxy-2-propanol / ethanol solution in Example 1 using an autoclave. After impregnation, the wooden test piece was air dried in a fume hood at room temperature (20-25° C.) for one week.

[0074] Impregnation with a water-based solution

[0075] Pine sapwood (Pinus sylvestris L) wooden test pieces (22.4×48×163 mm) were prepared. Before impregnation, the tangential and radial surfaces of the wooden test pieces were planed. The wooden test pieces were then conditioned at 20°C and 65% relative humidity (Rh). Ten wooden test pieces were used for moisture measurement. They were oven dried at a temperature of 103°C for 18 hours and the weight was recorded. The average moisture content before impregnation was 8.6%.

[0076] The wooden test pieces were packed together and separated from each other by plastic grids. 20 test pieces were placed in each of three plastic containers and secured with weights to ensure that the wooden test pieces remained submerged during the entire impregnation process. One of three different medetomidine solutions (solution A, solution B and solution C, all from Example 1) was added to each container. The container was placed in an autoclave. The impregnation procedure started with an initial step in which the container containing the wooden test piece was kept under vacuum for 30 minutes to remove air from the wood structure. A pressure of 10 bar was then applied for 1 hour.

[0077] Weigh the wooden test piece directly after immersion and record the wet uptake (kg / m 3 ), then air dried for 12 hours, and then dried at 103°C for 18 hours. The average moisture absorption of impregnation solutions A, B and C is higher than 700 kg / m 3 .

[0078] Table 1 - Uptake of impregnation solution

[0079]

[0080] Example 3

[0081] First field test

[0082] Wooden test pieces impregnated with the solvent-based solution were mounted on aluminum frames and submerged at the Kristineberg Marine Biological Research Station on the west coast of Sweden between June 1, 2020 and May 28, 2021. Untreated reference pieces ( Figure 1 , upper left) was completely perforated by shipworms. The wooden test piece treated with 0.8% medetomidine ethanol solution (Example 1) had only a few shipworms, such as Figure 1 shown.

[0083] Second field test

[0084] Wooden test pieces impregnated with various water-based solutions (Example 1) were mounted on aluminum frames and submerged from May 28, 2021 to June 9, 2022 at the Kristineberg Marine Biological Research Station on the west coast of Sweden.

[0085] Figure 2 Table 2 shows the results after 1 year of immersion of wooden test pieces impregnated with water-based solutions of various medetomidine concentrations (0.1%, 0.5% and 1% prepared in Example 1) and treated and untreated reference pieces.

[0086] Table 2 - Test results

[0087] Name / Number illustrate Cross-cutting results Tr Ref 287 CCA-processed reference parts Original, no shipworms Ref 312 Unprocessed references Completely perforated by shipworms Ref 283 Unprocessed references Completely perforated by shipworms 7345 0.1% treatment Completely perforated by shipworms 7347 0.1% treatment Completely perforated by shipworms 7366 0.5% treatment Severely perforated by shipworms 7367 0.5% treatment Severely perforated by shipworms 7382 1% Treatment Only a few shipworms 7388 1% Treatment Only a few shipworms

[0088] The above embodiments are to be understood as several illustrative examples of the present invention. It will be appreciated by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the scope of the present invention. In particular, different partial technical solutions in different embodiments may be combined into other configurations where technically feasible. However, the scope of the present invention is defined by the appended claims.

Claims

1. A method of reducing or preventing attack by marine wood-boring insects on wood present in a marine environment, the method comprising impregnating at least a portion of the wood with a composition comprising medetomidine or an enantiomer, salt or base thereof in an amount of at least 0.05% by weight, based on the total weight of the composition.

2. The method according to claim 1, wherein the composition comprises medetomidine or an enantiomer, salt or base thereof in an amount of 0.05% to 5% by weight based on the total weight of the composition.

3. The method according to claim 2, wherein the composition comprises medetomidine or its enantiomer, salt or base in an amount of 0.1 to 5 wt% based on the total weight of the composition, preferably in an amount of 0.1 to 2.5 wt% based on the total weight of the composition.

4. The method according to claim 3, wherein the composition comprises medetomidine or its enantiomer, salt or base in an amount of 0.5 to 2.5 wt% based on the total weight of the composition, preferably in an amount of 0.5 to 1.0 wt% based on the total weight of the composition.

5. The method according to any one of claims 1 to 4, wherein the composition is a solution comprising medetomidine or an enantiomer, a salt or a base thereof.

6. The method of claim 5, wherein the solution comprises a solvent selected from the group consisting of water, carboxylic acid, alcohol, and any combination thereof.

7. The method of claim 6, wherein the solution comprises a solvent selected from the group consisting of water, acetic acid, methanol, ethanol, butane-1,4-diol, benzyl alcohol, 1-methoxypropan-2-ol, and any combination thereof.

8. The method according to any one of claims 5 to 7, wherein the solution is an acidic aqueous solution comprising medetomidine or its enantiomer, salt or base, having a pH below 7, preferably selected in the interval of 4 to 6, more preferably selected in the interval of 4.5 to 5.5, such as about 5.

0.

9. The method according to claim 8, further comprising: dissolving medetomidine or its enantiomer, salt or base in an acidic aqueous solvent to form a concentrated acidic aqueous solution having a first pH, wherein the acidic aqueous solvent is preferably a mixture of water and at least one carboxylic acid; and The concentrated acidic aqueous solution is diluted with water to form an acidic aqueous solution having a second pH below 7, wherein the first pH is lower than the second pH.

10. The method of any one of claims 1 to 9, wherein impregnating at least a portion of the wood comprises impregnating the wood with the composition.

11. The method of any one of claims 1 to 10, wherein impregnating at least a portion of the wood comprises impregnating at least a portion of the wood with the composition in a closed high pressure system.

12. The method of any one of claims 1 to 10, wherein impregnating at least a portion of the wood comprises impregnating at least a portion of the wood with the composition under vacuum.

13. The method of any one of claims 1 to 10, wherein impregnating at least a portion of the wood comprises impregnating at least a portion of the wood with the composition while applying oscillating pressure or a series of vacuum cycles.

14. The method of any one of claims 1 to 10, wherein impregnating at least a portion of the wood comprises immersing at least a portion of the wood in the composition.

15. Use of a composition comprising medetomidine or its enantiomer, salt or base in an amount of at least 0.05% by weight, based on the total weight of the composition, for reducing or preventing attack by marine wood-boring insects on wood present in a marine environment.

16. The use according to claim 1, wherein the composition comprises medetomidine or its enantiomer, salt or base in an amount of 0.05% to 5% by weight based on the total weight of the composition.

17. Use according to claim 16, wherein the composition comprises medetomidine or its enantiomer, salt or base in an amount of 0.1 to 5 wt% based on the total weight of the composition, preferably in an amount of 0.1 to 2.5 wt% based on the total weight of the composition.

18. Use according to claim 17, wherein the composition comprises medetomidine or its enantiomer, salt or base in an amount of 0.5 to 2.5 wt% based on the total weight of the composition, preferably in an amount of 0.5 to 1.0 wt% based on the total weight of the composition.

19. Use according to any one of claims 15 to 18, wherein the composition is a solution comprising medetomidine or an enantiomer, a salt or a base thereof.

20. The use according to claim 19, wherein the solution comprises a solvent selected from the group consisting of water, carboxylic acids, alcohols and any combination thereof.

21. The use according to claim 20, wherein the solution comprises a solvent selected from the group consisting of water, acetic acid, methanol, ethanol, butane-1,4-diol, benzyl alcohol, 1-methoxypropan-2-ol, and any combination thereof.

22. Use according to any one of claims 20 to 21, wherein the solution is an acidic aqueous solution comprising medetomidine or its enantiomer, salt or base, having a pH below 7, preferably selected in the interval of 4 to 6, more preferably selected in the interval of 4.5 to 5.5, such as about 5.0.

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