Process for the preparation of polyurea microparticles and microparticles so obtained

Abstract

The present invention relates to a process for the preparation of polyurea microparticles suspension including at least one active ingredient in eco-friendly microsystems. The present invention relates also to polyurea microparticles suspension obtainable by the process of the invention and their use for delivering said active ingredient in agriculture.

Description

[0001] P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0002] TITLE:

[0003] PROCESS FOR THE PREPARATION OF POLYUREA MICROPARTICLES AND MICROPARTICLES SO OBTAINED

[0004] ***** ***** *****

[0005] FIELD OF THE INVENTION

[0006] The present invention relates to a process for the preparation of a suspension of p polyurea microparticles including hydrophobic active ingredients in eco-friendly microsystems.

[0007] The present invention relates also to dry microparticles suspension obtainable by the process of the invention and their use for delivering said active ingredient in agriculture.

[0008] STATE OF THE ART

[0009] Microplastics is a general term indicating solid polymeric particles less than 5 mm in length according to the European Chemicals Agency (ECHA). Once in the environment, not biodegradable microplastics are accumulated in marine, freshwater, and terrestrial ecosystems which lead to a big impact on the wildlife as well as on the whole food chain.

[0010] Many species mistake microplastics for food, leading to ingestion and potential health problems such as starvation, suffocation, and entanglement as reported by different researchers in the last decades. Furthermore, in an environment dominated by particulate material, microplastics can alter soil chemistry and affect soil organisms’ fitness and function.

[0011] In the literature it is shown that microplastics are frequently detected also in human samples since people are potentially exposed to microplastics through oral intake, inhalation, and skin contact as common ways. The effects connected with their introduction in human body mainly consist of oxidative stress, DNA damage, organ dysfunction, metabolic disorder, immune response, neurotoxicity, as well as reproductive and developmental toxicity. In addition, epidemiological evidence suggests that a variety of chronic diseases may be related to microplastics exposure.P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0012] In light of the above, in 2023, the European Commission adopted a REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) restriction on microplastics intentionally added to products and a proposal for a Regulation on preventing plastic pellet losses to the environment.

[0013] The Ell aims to reduce microplastic releases by 30% by 2030. This will be achieved by

[0014] - reducing plastic pollution (as these degrade into microplastics),

[0015] - restricting the use of intentionally added microplastics to products, and

[0016] - reducing unintentional microplastic releases

[0017] The regulation defines synthetic polymer microplastic as: “polymers that are solid and which either are contained in particles and constitute at least 1 % by weight of those particles, or build a continuous surface coating on particles, where at least 1 % by weight of those particles fulfill either of the following conditions:

[0018] (a) All dimensions of the particles are equal to or less than 5 mm.

[0019] (b) The length of the particles is equal to or less than 15 mm and their length to diameter ratio is greater than 3.”

[0020] However, some exceptions are included, such as:

[0021] • degradable or water-soluble (>2 g / l) polymers and natural polymers that have not been chemically modified,

[0022] • biodegradable polymers, and

[0023] • polymers with no carbon atoms within their own structure.

[0024] Crop protection compounds, including herbicides, insecticides, fungicides, and plant nutrients are often encapsulated either in polymeric matrices or within a core-shell system in their formulation form to achieve one or more purposes listed below:

[0025] • obtaining an active ingredient-controlled release for optimum effectiveness, • retarding the losses of volatile components,

[0026] • protecting the active ingredient against light and oxidation,

[0027] • protecting either employers or final users from harmful or unpleasant materials,

[0028] • preventing premature chemical reactions with other mixture components,P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0029] and

[0030] • reducing actives side effects such as crop toxicity and drifting.

[0031] Nowadays, synthetic polymers such as polyacrylates, polyamides, polyureas or polyurethanes represent the most common materials for encapsulating pesticides. Unfortunately, such materials lack of the required REACH characteristics described above, and the development of new environmentally friendly products is needed. Nevertheless, polyurea materials are still widely used in agrochemical industry since such polymer class possess unique attributes which make them ideal for entrapping specific active ingredients. These attributes include a wide range of physical and mechanical properties, chemical functionality, and diversity in specific polymer characteristics.

[0032] Looking at the prior knowledge, no methods have been described to obtain polyurea microparticles from relatively harmless starting materials and having an adequate biodegradation profile.

[0033] WO 2021 / 260017 illustrates the process to produce microcapsules from NCO terminated polyester-polyol polyisocyanate prepolymer containing at least 2 isocyanate groups and a polyamine as reagent materials. However, polyesters are known to undergo hydrolysis after some time in the environment. In fact, the biodegradability of the examples shown in the document described that the maximum value reached for the products was 38.8%. This result is not in compliance with the Commission Regulation 2023 / 2055 of 25 September 2023 amending Annex XVII to Regulation (EC) No 1907 / 2006 of the European Parliament and of the Council concerning the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) as regards synthetic polymer microparticles. According to the above, a tested item is considered to meet the biodegradation requirement if 60% mineralization is measured as consumed O2 or evolved CO2.

[0034] Moreover, the examples within the document describe the use of aromatic polyisocyanate (i.e. MDI, pMDI, TDI) as preferred reagents which are classified as extremely toxic, sometimes lethal by inhalation, materials (EC regulation 1272 / 2008). The aforesaid issues may result in difficulties on product handling asP024103WO-01 Notarbartolo & Gervasi S.p.A.

[0035] well as a concern for soil and aquatic environment.

[0036] It is an object of the invention to provide improved biodegradable microparticles for use in agriculture having improved properties, such as improved stability and a controlled and tunable release of the active ingredients, specifically for active ingredients having a high volatility or being in a liquid state below 70°C.

[0037] SUMMARY OF THE INVENTION

[0038] It has now been unexpectedly found by the present inventors that it is possible to produce a suspension (CS) microparticles suitable for agricultural use, comprising at least one active ingredient which is encapsulated within a biodegradable polyurea matrix.

[0039] The use of such polyurea microparticle suspension permits the tuned and controlled delivery of active ingredients ensuring a long term formulation stability and excellent flowing behavior at the same time.

[0040] Therefore, the invention relates to a process for the preparation of a suspension containing at least one polyurea microparticle, wherein said at least one microparticle includes at least one active ingredient and is prepared by homopolymerization through emulsification-condensation procedure, said process comprising the step of:

[0041] a) preparing an oil phase of at least one active ingredient, lysine ethyl ester diisocyanate, and a catalyst

[0042] b) preparing an aqueous phase;

[0043] c) preparing an oil in water (O / W) emulsion by mixing the oil phase of step a) and aqueous phase of step b);

[0044] d) obtaining a suspension of at least one microparticle including the at least one active ingredient of step a).

[0045] The inventors found out an inventive process that allows to obtain a suspension of microparticles comprising at least one active ingredient for a tuned delivery in agriculture.P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0046] In the present invention the terms microsphere and microparticle are used to mean a particle made of a polymer and in the particle size range of 1-1000 pm as measured by microscopy, laser diffraction and sieving methods.

[0047] Specifically the microparticle / microsphere of the invention is not a capsule having a structure composed of a shell and a core, but is like a matrix wherein the active ingredient is dispersed as demonstrated in the experimental part.

[0048] The inventors of the present invention hence found out that the process according to the invention allows to obtain polyurea microparticles suspension.

[0049] Moreover, advantageously the process of the invention uses an eco-friendly polyurea obtained by homo-polymerization of lysine ethyl ester diisocyanate to include in the polyurea microparticles very different crop protection agents. The use of an eco-friendly polyurea matrix allows to avoid the use of microplastics and meet the requirements of the REACH restriction adopted by the European Commission. The inventors faced with the problem of encapsulating very highly volatile liquid active ingredients and with active ingredients having a low solubilization rate.

[0050] The inventors advantageously found out the process for obtaining microparticles / microspheres suitable for including highly volatile liquid active ingredients.

[0051] The microparticles so obtained are solid and very stable in an aqueous medium and can be delivered as a suspension according to the present invention.

[0052] In a very advantageous and preferred embodiment the active ingredients are selected from the group selected from clomazone, bixlozone, lambda-cyhalothrin and triallate. In an even more advantageous and preferred embodiment the active ingredient is clomazone.

[0053] In a preferred embodiment the inventors found a one-step homo-polymerization method to provide improved microparticles for use in agriculture having enhanced properties in terms of physical stability and user-handling characteristics.

[0054] In another aspect the invention relates to a suspension of at least one of polyurea microparticle including the at least one active ingredient obtainable from the process of the invention.P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0055] In a preferred and advantageous embodiment, the invention relates to a suspension of polyurea microparticles matrix-encapsulating the at least one active ingredient, wherein the at least one active ingredient is a highly volatile liquid compound, preferably clomazone.

[0056] In a more preferred and advantageous embodiment the matrix-encapsulated clomazone is in amount from 10 to 60% w / w, preferably from 20 to 30% w / w with respect to the total amount of the formulation.

[0057] The water dispersible dry microparticles obtainable by the process of the invention are suitable for delivering the active ingredients in agriculture field.

[0058] Advantageously the microparticles of the invention allow a tuned and controlled release of the active ingredient, depending on the action of the active principle. In a further aspect, the present invention relates to the use of said microspheres in agriculture for delivering one or more active ingredients.

[0059] DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 shows the results of the proof of concept for macroparticles. Spheres obtained for the study (1A); Single whole capsule (1B); Microparticle split in half (1C).

[0061] Figure 2 shows the FTIR spectrum of technical grade clomazone (2A) and microsphere example (2B) respectively.

[0062] Figure 3 shows a microphotograph of example 1.

[0063] Figure 4 shows the appearance of plant plots for visual inspection after 14 days. Untreated corn and OSR pots (Panel A); post treatment com samples (Panel B) post treatment OSR samples (Panel C).

[0064] Figure 5 shows the percentage of phytotoxicity and efficacy according to Example 1.

[0065] DETAILED DESCRIPTION OF THE INVENTION

[0066] Therefore, the invention relates to the invention relates to a process for the preparation of a suspension containing at least one polyurea microparticle, wherein said at least microparticle includes at least one active ingredient and is prepared byP024103WO-01 Notarbartolo & Gervasi S.p.A.

[0067] homo-polymerization through emulsification-condensation procedure, said process comprising the step of:

[0068] a) preparing an oil phase of at least one active ingredient, lysine ethyl ester diisocyanate and a catalyst;

[0069] b) preparing an aqueous phase;

[0070] c) preparing an oil in water (O / W) emulsion by mixing the oil phase of step a) and aqueous phase of step b) and;

[0071] d) obtaining a suspension of at least one microparticle including the at least one active ingredient of step a).

[0072] In the present description the following terms and definitions will be used:

[0073] - “microparticle” means a particle made of a polymer and in the particle size range of 1- 1000 pm as measured by microscopy, laser diffraction and sieving methods and comprises in its definition the “microsphere”;

[0074] - the term “active ingredient” refers to any hydrophilic or hydrophobic chemical or biological component (ora combination thereof), the application of which causes or provide a beneficial and / or useful effect in agriculture including, but not limited to fertilizers and pesticides including acaricides, fungicides, herbicides, insecticides, and nematicides;

[0075] - “highly volatile liquid” means a liquid having a vapour pressure equal to or above 1 10’4mm Hg, and

[0076] - the term homo-polymerization refers to a polymerization process that produces a homopolymer by reacting a single, identical type of monomer to form long, uniform polymer chains.

[0077] The process comprises the step a) of preparing an oil phase of at least one active ingredient and lysine ethyl ester diisocyanate.

[0078] Preferably, the preparation provides for dissolving lysine ethyl ester diisocyanate in the at least one active ingredient.

[0079] The active ingredient can be preferably selected from the group consisting of fertilizers, pesticides, comprising preferably acaricides, fungicides, herbicides, insecticides, and nematicides.P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0080] More preferably, the active ingredient is a highly volatile liquid active ingredient, a compound, solid or liquid, having a low solubilization rate, harmful compounds for workers and final users or compounds which need a controlled release.

[0081] Specifically and still more preferably, the at least one active ingredient can be selected from the group consisting of

[0082] - an isoxazoline-derivate herbicide, preferably clomazone, bixolozone, pyroxasulfone, fenoxasulfone;

[0083] - a thiocarbamate herbicide, preferably triallate, diallate, butylate, cycloate, EPTC and molinate;

[0084] - a pyrethroid, preferably cyfluthrin, lambda-cyhalothrin, bifenthrin, permethrin and resmethrin;

[0085] - a dinitroaniline, preferably pendimethalin, trifluralin, ethalfluralin, oryzalin, butralin, benefin / benfluralin and prodiamine

[0086] - a terpen and / or terpeoid, preferably d-limonene, azadirachtins, carvacrol, 1,8-cineole, anisole, limonene, [3-pinene, linalool, menthone, a-pinene, pulegone, myrcene eugenol, borneol, menthol, isomenthol, anethole, camphor, carvone, menthyl acetate, linalyl acetate, thymol, p-cymene, y-terpinene, a-terpineol, 4-terpineol, citronellol and geraniol, and

[0087] - an essential oil, preferably cinnamon oil, citronella oil, clove oil, eucalyptus oil, lemongrass oil, mint oil, mint oil, orange oil, peppermint oil, rosemary oil and thyme oil.

[0088] More preferably the at least one active ingredient is selected from the group consisting of:

[0089] - an isoxazoline-derivate herbicide, still more preferably clomazone, bixolozone, pyroxasulfone, fenoxasulfone and even more preferably clomazone;

[0090] - a thiocarbamate herbicide, still more preferably triallate, diallate, butylate, cycloate, EPTC and molinate; and

[0091] - a pyrethroid, still more preferably cyfluthrin, lambda-cyhalothrin, bifenthrin, permethrin and resmethrin.P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0092] In a preferred and advantageous embodiment, the at least one active ingredient is a highly volatile liquid compound.

[0093] In a more preferred and advantageous embodiment, the at least one active ingredient is selected from the group consisting of clomazone, bixlozone, triallate and lambda-cyhalothrin.

[0094] The most preferred active ingredient is clomazone.

[0095] Clomazone, the common name for 2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone, is an active ingredient in highly effective herbicides that are selective against perennial weeds, including grasses and broadleaves. Clomazone works by inhibiting the biosynthesis of carotenoids in the plant; a plant affected by clomazone exhibits progressive whitening with increased dosage. Herbicides containing clomazone are applied to the soil for control of weeds on beans, cabbage, cucumbers, cotton, melons, mint, peas, peppers, rice, soybeans, squash, sugarcane, sweet potatoes, tobacco and tuberous vegetables. Such herbicides are selective against perennial weeds, including grasses and broadleaves.

[0096] Clomazone is a highly volatile compound and therefore it is a problematic active ingredient.

[0097] Lambda-cyhalothrin, common name (RS)-alpha-cyano-3-phenoxybenzyl 3-(2-chloro-3,3,3-trifluoropropenyl)-2,2, -dimethylcyclopropanecarboxylate is a synthetic pyrethroid insecticide and acaricide used to control a wide range of pests in a variety of applications. Pests controlled include aphids, Colorado beetles and butterfly larvae. Crops on which it may be applied include cotton, cereals, hops, ornamentals, potatoes, vegetables, or others.

[0098] The same can be repeated for bixolozone, that is a highly volatile liquid herbicide characterized by high vapor tension, hence a significant volatility. Lambda-cyhalothrin, common name of (RS)-alpha-cyano-3-phenoxybenzyl 3-(2-chloro-3,3,3-trifluoropropenyl)-2,2, -dimethylcyclopropanecarboxylate is a synthetic pyrethroid insecticide and acaricide used to control a wide range of pests in a variety of applications. Pests controlled include aphids, Colorado beetles and butterflyP024103WO-01 Notarbartolo & Gervasi S.p.A.

[0099] larvae. Crops on which it may be applied include cotton, cereals, hops, ornamentals, potatoes, vegetables, or others.

[0100] Triallate, IIIPAC name S-(2,3,3-trichloroprop-2-enyl) N,N-di(propan-2-yl) carbamothioate, belongs to the thiocarbamate chemical class. It is a pre-emergence selective herbicide used to control grass weeds in fields and pulse crops. It is used selectively to control wild oats, black grass, and annual meadow grass in barley, wheat, peas, lentils, rye, maize, beets, brassicas, carrots, and onions.

[0101] Triallate needs to be finely released from capsules to carry out a proper weed control with no side effect on crops therefore it is a problematic active ingredient.

[0102] Lambda-cyhalothrin, common name of (RS)-alpha-cyano-3-phenoxybenzyl 3-(2-chloro-3,3,3-trifluoropropenyl)-2,2, -dimethylcyclopropanecarboxylate is a synthetic pyrethroid insecticide and acaricide used to control a wide range of pests in a variety of applications. Pests controlled include aphids, Colorado beetles and butterfly larvae. Crops on which it may be applied include cotton, cereals, hops, ornamentals, potatoes, vegetables, or others.

[0103] Lambda-cyhalothrin has a high toxicity degree and it is potentially lethal by inhalation and therefore it is a problematic active ingredient.

[0104] Lysine ethyl ester diisocyanate is the monomer of step a) that is used for preparing the oil phase together with the at least one active ingredient.

[0105] Preferably the monomer is dissolved in the at least one active ingredient, more preferably in the amount in the range ratio from 1 : 2.5 to 1.10, preferably 1 :5 (w / w). In a preferred embodiment the oil phase of step a) comprises the at least one active ingredient in the range from 25% to 95%, preferably from 80% to 90% (w / w) with respect to the total weight of the oil phase.

[0106] The process comprises the step b) of preparing an aqueous phase.

[0107] In step b) the aqueous phase is prepared preferably by adding an excipient selected from the group consisting of a wetting agent, an emulsifying agent, a dispersing agent and a mixture thereof.

[0108] Preferably, the wetting agent of is selected from the group consisting of sodium dodecyl sulfate, sodium dioctylsulfosuccinate, sodium lauryl sulfate, alkylbenzeneP024103WO-01 Notarbartolo & Gervasi S.p.A.

[0109] sulfonates, alkylphenolethocylates, polysorbates, polyether alcohols and polypropylene glycol-ethylene oxide condensates more preferably it is sodium dodecyl sulfate.

[0110] The wetting agent of the aqueous phase is preferably dissolved in water in a weight percentage (%) in the range from 1 % to 10%, preferably from 2 to 3 % (w / w) with respect to the total weight of the aqueous phase.

[0111] Preferably, the emulsifying agent of step b) is selected from the group consisting of calcium lignosulphonate, tristyrylphenol phosphate, castor oil ethoxylate, sodium lauryl sulfate, alkylbenzene sulfonates, alkylphenolethocylates, polysorbates, polyether alcohols and polypropylene glycol-ethylene oxide condensates. more preferably it is selected from tristyrylphenol phosphate, castor oil ethoxylate and their mixture.

[0112] The emulsifying agent of is added in water in a weight percentage (%) in the range from 0.5% to 3%, preferably from 1 % to 2% (w / w) with respect to the total weight of the aqueous phase.

[0113] Preferably, the dispersing agent of step is selected from the group consisting of xanthan gum, fatty acid esters and ethoxylated fatty acid esters, sodium alkyl sulfosuccinates, allyloxybenzene sulfonates, poly(vinyl alcohol), guar gum and hydroxyethyl, more preferably it is a xanthan gum.

[0114] The dispersing agent of step is added in water in a weight percentage (%) in the range from 0.1% to 3%, preferably from 0.2 to 1% (w / w) with respect to the total weight of the aqueous phase.

[0115] The process provides for a step c) of preparing an oil in water (O / W) emulsion by mixing the oil phase of step a) and aqueous phase of step b).

[0116] Preferably, the process comprises the step c) of adding the aqueous phase of step b) in the oil phase of step a), thus obtaining an oil in water (O / W) emulsion.

[0117] In the oil in water (O / W) emulsion, the above excipient are present preferably in the following amounts with respect to the total amount of the emulsion:P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0118] - L-lysine ethyl ester diisocyanate, the monomer of step a) is in an amount in the range from 1% to 8% (w / w), preferably from 2 to 6%, more preferably from 2.2% to 5% (w / w);

[0119] - the at least one active ingredient in the range from 5% to 50%, preferably from 10% to 35% (w / w);

[0120] - the wetting agent is in the range from 0.1 % to 8%, preferably 1.8% (w / w). - the emulsifying agent is in the range from 0.5% to 6%, preferably from 1 % to 2% (w / w),;

[0121] - the dispersing agent is in the range from 0.1% to 5%, preferably from 0.2% to 1% (w / w);

[0122] Preferably, before step c) a pre-heating is carried out of the aqueous phase and the oil phase, independently from each other, more preferably at a temperature in the range from 20°C to 80°C, still more preferably at 50°C.

[0123] In an advantageous and preferred embodiment, the aqueous phase is poured dropwise into oil phase and homogenized. The homogenization can be carried out preferably with a speed in the range from 4000 to 10000 rpm for 3-20 minutes, more preferably at 6000 rpm with a homogenizer known in the art.

[0124] The invention provides for step d) of adding a catalyst to the water (O / W) emulsion of step c).

[0125] The catalyst is preferably selected from the group consisting of dibutyltin dilaurate, 1 ,4-diazabicyclo [2.2.2] octane, cobaltous stearate, triethylenediamine, stannous 2-ethylhexoate, more preferably it is dibutyltin dilaurate.

[0126] The catalyst is preferably added in an amount in the range from 0.000000009% to 0.2, preferably 0.000001 to 0.1% (w / w) with respect to the aqueous phase of step b).

[0127] The catalyst allows to obtain the homo-polymerization of L-lysine ethyl ester diisocyanate to obtain polylurea microparticles in a suspension.

[0128] Preferably, after the addition of the at least one catalyst to the O / W emulsion in step d), the resulting emulsion is heated and kept under magnetic stirring.P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0129] In an advantageous and preferred embodiment, the stirring is carried out preferably at a temperature in the range from 20°C to 80°C, preferably at 50°C, more preferably with a speed in the range from 500 to 1500 rpm for preferably 4 hours, still more preferably at 1000 rpm for 4 hours with a stirrer known in the art.

[0130] The process comprises the step e) of obtaining a polyurea microparticles suspensions including the at least one active ingredient of step a).

[0131] As it will be clear from the experimental part reported below, the microparticle / microsphere of the invention is a matrix wherein the active ingredient is dispersed as demonstrated in the experimental part.

[0132] Therefore the process of the invention allowed the inclusion through a matrixencapsulation of preferably very highly volatile liquid active ingredients and having a low solubilization rate.

[0133] The process of the invention advantageously permits the matrix-encapsulation of one or more active ingredients with a loading in the range from 25 to 95% (w / w), preferably from 30 to 90% (w / w) with respect to the total weight of the microparticle. In the preferred and advantageous embodiment, wherein the active ingredient is clomazone, the matrix-encapsulated clomazone is in amount from 30 to 95 % (w / w), preferably from 40 to 95 % (w / w) with respect to the total weight of the microparticle. The use of an eco-friendly polyurea matrix allows to avoid the use of microplastics and meet the requirements of the REACH restriction adopted by the European Commission.

[0134] In another aspect, the invention relates to a suspension of polyurea microparticles including the at least one active ingredient obtainable from the process of the invention.

[0135] Specifically the microparticle / microsphere of the invention is not a capsule having a structure composed of a shell and a core, but is like a matrix wherein the active ingredient is dispersed as demonstrated in the experimental part.

[0136] In a preferred and advantageous embodiment, the invention relates to a suspension of polyurea microparticles including the at least one active ingredient, wherein the at least one active ingredient is a highly volatile liquid compound, preferablyP024103WO-01 Notarbartolo & Gervasi S.p.A.

[0137] clomazone.

[0138] Advantageously the suspension of the invention comprises a microparticle capable to release an amount of the at least one active ingredient in the range from 1 to 100%, with respect to the whole amount of the at least one active ingredient of the microparticle suspension.

[0139] The inventors advantageously found out a process for obtaining microparticles suitable for matrix-encapsulating highly volatile liquid active ingredients. The microparticles so obtained are solid and very stable.

[0140] In a very advantageous and preferred embodiment the active ingredient is clomazone.

[0141] The polyurea microparticles suspensions including the at least one active ingredient obtainable by the process of the invention are suitable for delivering one or more active ingredients in agriculture field.

[0142] Advantageously the microparticles suspension of the invention allows a tuned and controlled release of the active ingredient, depending on the action of the active principle.

[0143] Without being bound to any theory, the inventors realized that the suspension of the invention comprising the microparticles / microspheres including the at least one active ingredient was capable to properly eradicate the unwished plant growth process with negligible effects on crop cultures as shown in the experimental part, owing to the structure of the microparticles of the suspension, being each microparticle a matrix of homo-polymerized L-lysine ethyl ester diisocyanate containing the active ingredient obtained through a emulsification-condensation procedure.

[0144] Preferably, the polyurea microparticle has a D50 in the range from 1 pm to 40 pm, more preferably 1-15 pm and D90 in the range from 10 pm to 100 pm, more preferably from 15 pm to 40 pm as measured by a laser diffraction analyzer (more preferably analyzer Malvern 3000, Malvern Panalytical, Malvern, UK).P024103WG-01 Notarbartolo & Gervasi S.p.A.

[0145] In a further aspect, the present invention relates to the use of said polyurea microparticles suspension including the at least one active ingredient in agriculture for delivering one or more active ingredients

[0146] EXPERIMENTAL PART

[0147] Example 1 : Preparation and evaluation of a suspension of microparticles of the invention

[0148] The microencapsulation procedure used consisted of emulsification-condensation method. Hence a primary emulsion was obtained prior clomazone encapsulation in a solid matrix. L-Lysine ethyl ester diisocyanate (VWR, Milano, Italy) was used as the sole monomer. The monomer was dissolved in clomazone (Sipcam Oxon, Mezzana Bigli, Italy) in a 1 :5 ratio by weight, this mixture represented the oil phase of the primary emulsion. The aqueous phase was obtained by dissolving 1.8 g of sodium dodecyl sulfate (Geropon SDS, Solvay, Ospiate di Bollate, Italy) in 75.1 ml of deionized water. The two phases were pre-heated at 50°C, then the aqueous phase was poured dropwise into the dispersed phase and homogenized by an Ultraturrax T50, (IKA, Staufen, Germany) at 6000 rpm to obtain a O / W emulsion. A catalytic amount (8 pg) of dibutyltin dilaurate (VWR, Milano, Italy) was added to the reaction mixtures to start the homo-polymerization and the system was kept under magnetic stirring at 1000 RPM and 50°C for 4h. Lastly, the temperature was dropped down at room temperature whereas the sample have been stirring overnight to obtain a microparticle suspension. The formulation composition containing all the ingredients is reported in the below table 1.

[0149]

[0150] P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0151] Table 1. 0 / W emulsion composition

[0152] The loading of clomazone was found to be 17.9% (w / w) of the whole formulation by HPLC.

[0153] Particle size analyses were obtained by a laser diffraction analyzer (Malvern 3000, Malvern Panalytical, Malvern, UK) using water as dispersing medium, D50 and D90 obtained were 35.9 and 95.6 pm respectively.

[0154] The release of clomazone from the microparticles were analyzed by dispersing a known weight of powder in a fixed volume of hexane, the amount of released active ingredient was obtained by calculating the difference between the initial loading value and the clomazone amount measured in the supernatant normalized by the microparticle concentration after 1, 5, 15, 30 and 60 minutes.

[0155] Results are shown in Table 2.

[0156] Table 2. Clomazone releasing profile

[0157]

[0158] Several tests had also been conducted to analyze the homo-polymerization process in order to get some insight in the microparticle formation. The procedure has been done working in macro size to make it easier the study (figure 1 A). The idea was to observe what type of particles are formed using this methodology. Pictures 1 B and 1 C show the proof of concept about the homo-polymerization events occurred during the sphere maturation, the images clearly depict the formation of a homogenous solid matrix where clomazone is entrapped within. The particles of the actual formulation obtained as described before have also been analyzed by infrared spectroscopy by using FTIR spectrometer (Frontier, Perkin Elmer , Waltham, MA, USA) in absorbance mode with the range of 4000 to 650 cm’1’ as shown in figure 2. The distinctive clomazone peaksP024103WO-01 Notarbartolo & Gervasi S.p.A.

[0159] (figure 2A) are also well detectable in the particle formulation pointing out that clomazone itself is dispersed in the homo-polymer obtained. As final point, Figure 3 depicts a microphotograph of the CS microspheres suspended in their aqueous medium after complete polymerization.

[0160] Efficacy and phytotoxicity evaluations were also performed in glasshouse in order to evaluate the selectivity on oilseed rape (Delight variety, OSR) and com (PR36Y03 variety). Echinochloa crus-galli (ECHCG), weed was used as target species and the formulation was compared against untreated sample pots and clomazone emulsifiable concentrates (EC, 500g / l). The dose applied for com was 80 g / ha whereas 90 g / ha were chosen for oilseed rape treatment (dose n). The application took place just after the sowing of 15 seeds / container, and phytotoxicity symptoms (bleaching) had been evaluated for 14 days. From the date recorded during the whole trial period, it was observed that all the test items showed a significantly different bleaching profile as depicted in Figures 4 and 5.

[0161] More in detail, Panel A in figure 4 shows the appearance of untreated sample pots of both com and OSR respectively: no bleaching or other signs of toxicity were detected during the whole test. In panel B are shown com pots treated by Sirtaki CS (a commercial product based on non-biodegradable polyurethane microcapsules), an emulsifiable concentrate and polyurea microparticles formulation respectively treated using two different doses, namely 80 and 160 gai / ha.

[0162] From the pictures, it results clear that the emulsifiable concentrate treated plants resulted smaller and more whitened in comparison with the samples treated using included clomazone at both dosing. Different bleaching degree is also spotted between plants treated by Sirtaki and the new formulation where the latter showed a lower toxicity by visual inspection. A similar result was observed on OSR treated plants too (Panel C). In this case 90 and 180 gai / ha dosing were employed.

[0163] A quantitative analysis confirmed the results of the above (figure 5). The efficacy against ECHCG culture did not show any significant difference in all the samples taken into account since all the formulations reached the maximum value (black bars).P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0164] Anyway, a substantially variation in phytotoxicity, and hence selectivity, was observed among the formulations (white and grey bars for com and OSR samples respectively). Obviously, the emulsifiable concentrate, EC, showed the highest phytotoxicity in both cultures as consequence of the fast Al release on the soil ground.

[0165] On the other hand, a different scenario was observed in plants when matrix-encapsulated clomazone was tested: the commercial reference product Sirtaki showed a dose-depended bleaching on corn culture treated with 80 and 160 g / ha of active respectively (namely 40.0 and 67.5%). On the contrary, no dose related toxic effect was observed on OSR (22.5% for both doses). Surprisingly the toxicity level of the polyurea formulation herein described resulted substantially lower than the one observed in the reference product. In fact, at the dose “n” only 3.8 and 5 % of phytotoxicity was detected (80 g / ha and 90 g / ha on com and OSR respectively) whereas such values increased up to 31.3 (com) and 16.3% (OSR) when treated with “2n” dose, far below if compared with Sirtaki treatment.

[0166] In conclusion, the data confirm that the use Lysine diisocyanate in the inventive process allowed to encapsulate the active ingredient in high amount and in effective way as well as to properly eradicate the weed growth process with negligible effects on crop cultures.

[0167] Example 2: Preparation and evaluation of the suspension of microparticles of the invention containing bixlozone

[0168] A further microparticles suspension containing bixlozone (2-(2,4-Dichlorobenzyl)-4,4-dimethylisoxazolidin-3-one) as matrix-encapsulated active ingredient was obtained following the procedure described above. Bixlozone is a highly volatile liquid herbicide characterized by a high vapor tension, hence a significant volatility. The process of the invention allowed to achieve an active ingredient controlled release for optimum effectiveness as well as the reduction of side effects such as crop toxicity and drifting is necessary.

[0169] Table 3 shows the amount as %w / w of each component of the formulation.

[0170] Table 3. O / W emulsion compositionP024103WG-01 Notarbartolo & Gervasi S.p.A.

[0171]

[0172] The loading of bixolozone within the dry powder was found to be 19.6% (w / w) by HPLC considering the whole formulation.

[0173] Particle size analyses of D50 and D90 resulted 9.8 and 27.6 pm respectively as measured with a laser diffraction analyzer (Malvern 3000, Malvern Panalytical, Malvern, UK).

[0174] The release profile was evaluated with respect to the total amount of the active ingredient matrix-encapsulated according to the procedure described above.

[0175] Release profile is shown in Table 4.

[0176] Table 4. Bixolozone releasing profile

[0177]

[0178] Example 3: Preparation and evaluation of the suspension of microparticles of the invention containing lambda cyhalothrin

[0179] A microparticles suspension, CS, containing lambda cyhalothrin as matrix-encapsulated active ingredient was obtained following the procedure described in theP024103WG-01 Notarbartolo & Gervasi S.p.A.

[0180] example 1. Lambda cyhalothrin is a pyrethroid insecticide harmful to humans because of its severe side effects. The matrix-encapsulation of lambda cyhalothrin in a confined system is mandatory in several manufacturing processes to protect either employers or final users.

[0181] Table 5 shows the amount as %w / w of each component of the formulation.

[0182] Table 5. O / W emulsion composition

[0183]

[0184] The loading of lambda cyhalothrin within the dry powder was found to be 9.9% (w / w) of the whole formulation by HPLC.

[0185] The loading of lambda cyhalothrin was found to be 19.6% (w / w) of the whole formulation by HPLC. Particle size analyses of D50 and D90 resulted 8.7 and 14.4 pm respectively as measured with a laser diffraction analyzer (Malvern 3000, Malvern Panalytical, Malvern, UK).

[0186] The release profile of Lambda cyhalothrin from the microparticles was evaluated by HPLC.

[0187] Active ingredient release from the microparticles analyses were performed by dispersing a known weight of formulation in a fixed volume of hexane, the amount of released active ingredient was obtained by calculating the difference between the initial loading value and the clomazone amount measured in the supernatant normalized by the microparticle concentration after 1, 5, 15, 30 and 60 minutes. The release profile was evaluated with respect to the total amount of the active ingredient matrix-encapsulated.P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0188] Release profile is shown in Table 6.

[0189] Table 6. lambda cyhalothrin releasing profile

[0190]

[0191] Example 4: Preparation and evaluation of the microparticles of the invention containing triallate

[0192] A microparticles suspension, CS, containing triallate as encapsulated active ingredient was obtained following the procedure described in the example 1. Triallate is a herbicide belonging to the thiocarbamate class and it needs to be finely released from capsules to carry out a proper weed control with no side effect. In current example, SDS has been replaced by a mixture of surfactants, namely tristyrylphenol phosphate and castor oil ethoxylate. Furthermore, 1,4-Diazabicyclo[2.2.2]octane was used as catalyst instead of dibutyltin dilaurate.

[0193] Table 7 shows the amount as %w / w of each component of the formulation.

[0194] Table 7. O / W emulsion composition

[0195]

[0196] P024103WO-01 Notarbartolo & Gervasi S.p.A.

[0197] The loading of triallate within the dry powder was found to be 34.8% (w / w) of the whole formulation by HPLC.

[0198] Particle size analyses results showed values of 12.3 and 29.4 pm for d50 and d90 respectively as measured with a laser diffraction analyzer (Malvern 3000, Malvern Panalytical, Malvern, UK).

[0199] Triallate release profile from the microparticles analyses were performed by dispersing a known weight of formulation in a fixed volume of hexane, the amount of released active ingredient was obtained by calculating the difference between the initial loading value and the clomazone amount measured in the supernatant normalized by the microparticle concentration after 1, 5, 15, 30 and 60 minutes.

[0200] The release profile was evaluated with respect to the total amount of the active ingredient encapsulated.

[0201] The results are reported in Table 8.

[0202] Table 8. triallate releasing profile

[0203]

Claims

P024103WO-01 Notarbartolo & Gervasi S.p.A.CLAIMS1. A process for the preparation of a suspension containing at least one polyurea microparticle, wherein said at least microparticle includes at least one active ingredient and is prepared by homo-polymerization through emulsificationcondensation procedure, said process comprising the step of:a) preparing an oil phase of at least one active ingredient and lysine ethyl ester diisocyanate;b) preparing an aqueous phase;c) preparing an oil in water (O / W) emulsion by mixing the oil phase of step a) and aqueous phase of step b)d) adding a catalyst to the water (O / W) emulsion of step c); ande) obtaining a suspension of at least one polyurea microparticle including the at least one active ingredient of step a).

2. The process according to claim 1 , wherein the at least one active ingredient can be selected from the group consisting of- an herbicide selected from the group consisting of clomazone, bixolozone, pyroxasulfone, fenoxasulfone;- a thiocarbamate herbicide, preferably triallate, diallate, butylate, cycloate, EPTC and molinate;- a pyrethroid, preferably cyfluthrin, lambda-cyhalothrin, bifenthrin, permethrin and resmethrin;- a dinitroaniline, preferably pendimethalin, trifluralin, ethalfluralin, oryzalin, butralin, benefin / benfluralin and prodiamine- a terpen and / or terpeoid, preferably d-limonene, azadirachtins, carvacrol, 1,8-cineole, anisole, limonene, [3-pinene, linalool, menthone, a-pinene, pulegone, myrcene eugenol, borneol, menthol, isomenthol, anethole, camphor, carvone, menthyl acetate, linalyl acetate, thymol, p-cymene, y-terpinene, a-terpineol, 4-terpineol, citronellol and geraniol, andP024103WO-01 Notarbartolo & Gervasi S.p.A.- an essential oil, preferably cinnamon oil, citronella oil, clove oil, eucalyptus oil, lemongrass oil, mint oil, mint oil, orange oil, peppermint oil, rosemary oil and thyme oil.

3. The process according to claim 1 or claim 2, wherein the at least one active ingredient is a highly volatile liquid compound.

4. The process according to claim 1 or claim 2, wherein the at least one active ingredient is selected from the group consisting of clomazone, bixolozone, triallate and lambda-cyhalothrin, preferably it is clomazone.

5. The process according to anyone of claims 1 -4, wherein in step b) the aqueous phase is prepared by adding an excipient selected from the group consisting of a wetting agent in water, an emulsifying agent, a dispersing agent, a preservative agent and a mixture thereof.

6. The process according to anyone of claims 1 -5, wherein step c) is carried out by adding the aqueous phase of step b) in the oil phase of step a), thus obtaining an oil in water (O / W) emulsion.

7. The process according to anyone of claims 1 -6, wherein in step d) the catalyst is selected from the group consisting of dibutyltin dilaurate, 1 ,4-diazabicyclo [2.2.2] octane, cobaltous stearate, triethylenediamine, stannous 2-ethylhexoate, more preferably it is dibutyltin dilaurate or 1 ,4-diazabicyclo [2.2.2]octane.

8. A suspension of at least one polyurea microparticle matrix-encapsulating the at least one active ingredient obtainable from the process according to claims 1-7.

9. The suspension of at least one polyurea microparticle according to claim 8, wherein the at least one active ingredient is a highly volatile liquid compound, preferably clomazone.

10. A use of the suspension of at least one polyurea microparticle according to claim 9 for delivering at least one active ingredient in agriculture field.

Images