Process for producing oil-in-water (0 / w) nanoemulsions for industrial nanoemulsion end-use products

Abstract

The subject matter of the invention relates to an industrially scalable, economical, generally applicable, three-step process for producing nanoemulsions having small droplet size and high stability by a phase inversion composition ( PIC) method, without the use of organic solvents, preferably alcohols, customarily applied to achieve small droplet size as emulsifiers and / or formulation aids, at room temperature and atmospheric pressure, such that in a first step, the oil is homogenized with the emulsifier for several minutes, in a second step, a defined amount of water is added in a single portion and homogenized for 5-10 minutes, thereby obtaining a mixture forming a premix, in a third step, the premix is dispersed in water, thereby producing the nanoemulsion, wherein the preparation of the nanoemulsion does not require the use of high-speed or high-pressure homogenizers or ultrasonic equipment, and all processes are carried out at room temperature. The subject matter of the invention further relates to a fourth step of the process, in which additional substances, preferably water-based, water-soluble substances, preferably acids, bases, glycerin, alcohols, or substances interacting with water, preferably gelling agents, are added to the nanoemulsion prepared in the three steps, depending on the field of application, for the purpose of producing a nanoemulsion end- use product.

Description

[0001] Process for producing oil-in-water (O / W) nanoemulsions for industrial nanoemulsion end-use products

[0002] I . SUBJECT MATTER OF THE INVENTION

[0003] The subj ect matter of the invention is an industrially feasible , economical and generally applicable three-step process for producing a nanoemulsion having a small droplet si ze , preferably below 30 nm, and high stability by a phase inversion composition ( PIC ) method, without the use of organic solvents customarily applied for achieving small droplet si ze , preferably alcohols , as emulsi fiers or formulation aids , at ambient temperature and atmospheric pressure , in such a manner that

[0004] - as a first step, apolar substances ( oil or oils ) are homogenised with one or more emulsi fiers for several minutes ;

[0005] - as a second step, a predetermined amount of water is added in a single portion and the mixture is homogenised for 5-10 minutes , preferably until it becomes visually completely homogeneous , whereby the viscosity of the resulting mixture, referred to as the premix, increases and the mixture undergoes a slight temperature rise ;

[0006] - as a third step, the nanoemulsion is produced in such a manner that the premix is dispersed in water, wherein the dispersion of the premix is carried out , independently of scale , under intensive mixing and phase contact for less than 1-2 minutes , fol lowed by continuous mixing of the mixture for one hour, whereby the total preparation time of the nanoemulsion is 1 . 5 hours .

[0007] The subj ect matter of the invention further includes that the concentration of the nanoemulsion prepared in this manner can be adj usted either during formulation or by subsequent arbitrary dilution of the prepared nanoemulsion, depending on the intended application .

[0008] The stability of the nanoemulsion thus obtained, including its kinetic and thermodynamic stability as well as its pH tolerance , is confirmed by measurements . In the case of internal use , the nanoemulsion retains its stability even upon contact with gastric acid .

[0009] The subj ect matter of the invention further includes that , for preparing the nanoemulsion, there is no need to use monohydric or polyhydric alcohols of any carbon chain length as emulsi fiers and / or co-emulsi f iers or formulation aids , and there is no need to use high-speed or high-pressure homogenisers or ultrasonic devices , and all processes are carried out at ambient temperature , while the process according to the invention i s capable of achieving a signi ficantly smaller droplet si ze .

[0010] According to the solution forming the subject matter of the invention , it is therefore not necessary to use alcohols and / or organic solvents as emulsifiers or formulation aids for producing the nanoemulsion ; however , the subsequent addition of alcohols to the already prepared nanoemulsion for stabilising or antimicrobial purposes is not excluded, if required by the formulated system.

[0011] The subj ect matter of the invention further includes that the droplet si ze can be maintained upon scale-up, that is , when producing larger quantities of the nanoemulsion .

[0012] The subj ect matter of the invention further includes a fourth step of the process , during which further substances , preferably water-based and water-soluble substances , preferably acids , bases , glycerine , alcohols or substances interacting with water, preferably gelling agents , are added to the nanoemuls ion prepared in three steps , depending on the intended field o f use , preferably according to the groupings detailed below, for the purpose of producing a nanoemulsion end-use product , without limiting the scope of protection to the listed groups .

[0013] The subj ect matter of the invention further includes that the process does not require high-energy equipment , heat input, solvents or alcohols , large amounts of emulsi fiers or long production times , and the process according to the invention is more time-ef ficient and provides better yield than solutions known from the state of the art .

[0014] The subj ect matter of the invention further includes that the process is carried out at ambient temperature and atmospheric pressure .

[0015] The subj ect matter of the invention further includes the fields of use and forms of the products produced during the various steps of the process according to the invention, which are as follows :

[0016] - the premix produced in step 2 can be used as a plant protection agent when the premix is manually mixed with tap water, thereby producing a nanoemulsion that remains stable for several days ;

[0017] - the nanoemulsion produced in step 3 can be used in fields of application known from the state of the art ;

[0018] - the nanoemulsion end-use product produced in step 4 can be used in the following forms : as a liquid and / or spray as cosmetic products , plant care products , insect repellents , beverages and medicinal preparations , and, in gelled form, as gels , so ft gelatin capsules , cosmetic products and medicinal preparations . IN THE PROCESS ACCORDING TO THE SUBJECT MATTER OF THE INVENTION, THE MATERIALS LISTED AND GROUPED BELOW MAY BE USED WITHOUT LIMITING THE SCOPE OF PROTECTION THERETO.

[0019] Water :

[0020] During the experiments, deionised water is used; however, the process according to the invention does not exclude the use of distilled water, ultrapure water or other purified water, as well as the use of tap water and other waters containing dissolved salts for mixing with the prepared premix.

[0021] Emulsifiers, surfactants and co-surfactants:

[0022] - preferably Tween 80 (T80) (polyoxyethylene ( 20 ) sorbitan monooleate) ;

[0023] - preferably Tween 20 (T20) (polyoxyethylene ( 20 ) sorbitan monolaurate) ;

[0024] - other polyoxyethylene ( 20 ) sorbitan fatty acid esters, preferably Tween 40, Tween 60, Tween 65 and Tween 85 emulsifiers ;

[0025] - polyethylene glycols, preferably PEG-400, PEG-600, PEG-800,

[0026] PEG-1000 and PEG-2000 emulsifiers;

[0027] - sorbitan fatty acid esters, preferably Span 20 and Span 60;

[0028] - other emulsifiers known from the literature.

[0029] Oils - essential oils and essential oil mixtures:

[0030] - preferably lavender oil, lemon oil, peppermint oil, rose oil, pine oil, clove oil, rosemary oil and grapefruit oil, and mixtures thereof;

[0031] - other essential oils and essential oil mixtures known from the literature.

[0032] Oils - triglycerides and triglyceride mixtures:

[0033] - preferably walnut oil, grape seed oil, fractionated coconut oil, apricot kernel oil, rosehip seed oil and argan oil;

[0034] - other triglycerides or triglyceride mixtures known from the literature . Oil-soluble substances and active agents :

[0035] - preferably propolis (propolis extract ) ;

[0036] - preferably vitamin E ( tocopherol ) ;

[0037] - preferably Acmella extract ;

[0038] - other oil-soluble substances and active agents known from the literature .

[0039] Substances addable to the nanoemulsion in the fourth step for producing the nanoemulsion end-use product :

[0040] - preferably preservatives , such as phenoxyethanol ;

[0041] - preferably water-soluble substances and active agents , particularly preferably vitamin F;

[0042] - further preferably alcohols , particularly preferably ethanol and glycerine ;

[0043] - further preferably acids and bases ;

[0044] - further preferably gelling agents , particularly preferably xanthan gum and carbomer ; other components known from the literature , depending on the intended field of use .

[0045] DEFINITIONS

[0046] PREMIX : The product produced in step 2 of the process according to the subj ect matter of the invention . NANOEMULSION : In addition to its general , commonly known designation and meaning, in the present description it means the product produced in the third step of the process according to the invention .

[0047] NANOEMULSION END-USE PRODUCT : The product produced in the fourth step of the process according to the invention . PIC nanoemulsion phase inversion composition technique : a method suitable for producing a nanoemulsion, wherein, in this technique , a change in the composition of the constituents changes the hydrophilic-lipophilic behaviour of the emulsi fier .

[0048] PICT nanoemulsion technique : a phase inversion composition method suitable for producing a nanoemulsion, according to which the organic phase is added to the aqueous phase ; in the solution according to the invention, one of the techniques applied in the third step . PIC2 nanoemulsion technique : a phase inversion composition method suitable for producing a nanoemulsion, according to which the aqueous phase is added to the organic phase , which is also an applicable technique . PIC2 / PIC1 combined nanoemulsion technique : the combined solution according to the invention, being the technique applied in the second and third steps with which the examined samples were prepared, namely : first the organic phase is mixed with a small amount of water ( PIC2 ) , and then the resulting mixture is added to the aqueous phase ( PIC1 ) .

[0049] All three products produced by the process according to the subj ect matter of the invention and defined above can be used for direct application in various fields of use .

[0050] DESCRIPTION OF THE FIRST STEP OF THE PROCESS ACCORDING TO THE SUBJECT MATTER OF THE INVENTION , THE RESULT OF WHICH IS A MIXTURE OF EMULSIFIER AND OIL

[0051] The subj ect matter of the invention further includes that the emulsi fier and / or co-emulsi f ier used in the first step of the process according to the invention is selected depending on the quality of the oil .

[0052] The subj ect matter of the invention further includes that the emulsi fiers used in the first step of the process according to the invention are preferably

[0053] - polysorbate 80 (polyoxyethylene

[0020] sorbitan monooleate ,

[0054] Tween 80 ( T80 ) ) and

[0055] - polysorbate 20 (polyoxyethylene

[0020] sorbitan monolaurate , Tween 20 ( T20 ) ) .

[0056] The subj ect matter of the invention further includes that the ratio of the emulsi fiers used in the first step of the process according to the invention is set depending on the viscosity of the oil and / or oil mixture, in such a manner that the proportion of T80 increases with the viscosity and / or apolarity of the oil and / or oil mixture, preferably in the grouping detailed below:

[0057] - in the case of triglycerides, exclusively T80 may be used, or preferably the ratio of T80 to T20 is at least 1 / 1;

[0058] - in the case of essential oils, the T80 / T20 ratio is preferably less than or equal to 1 / 1, particularly preferably from 1 / 7 to 1 / 1, and particularly preferably from 2 / 5 to 1 / 1. The subject matter of the invention further includes that the ratio of the T80 emulsifier to the oil used in the first step of the process according to the invention preferably has a minimum value, below which, irrespective of the amount of T20 added, a clear, transparent nanoemulsion is not formed at a later stage.

[0059] In the first step of the process according to the subject matter of the invention, preferably a mixture of several different oils is used, particularly preferably an essential oil-essential oil mixture, a triglyceride-triglyceride mixture, or an essential oil-triglyceride mixture. The ideal emulsifier (co-emulsif ier, T80 and T20 ratios) ratios required for producing nanoemulsions of the different oils used were summarised, by oil type, in Table 5 of Figure 19.

[0060] The subject matter of the invention further includes that the adjustment of the emulsif ier-to-oil (E / O) ratio is carried out based on knowledge of the relationship between droplet size and the amount of emulsifier required to achieve the droplet size, taking into account that the required E / O ratio is inversely proportional to the droplet size, wherein the E / O ratio is preferably four, which corresponds to a nanoemulsion having a droplet size below 50 nm, which, in the case of colourless oil, means a clear, water-like transparent nanoemulsion, and in other cases a transparent nanoemulsion . The subj ect matter of the invention further includes that the optimal T80 / T20 and E / O ratios depending on the oil and / or oil mixture are set in accordance with the desired droplet si ze in such a manner that the components containing the emulsi fiers and oils are measured in any order and homogenised, thereby obtaining a homogeneous mixture at ambient temperature , preferably within five minutes . The E / O ratios are shown in Table 6 of Figure 19 and in

[0061] Diagram 20 of Figure 19.

[0062] DESCRIPTION OF THE SECOND STEP OF THE PROCESS ACCORDING TO THE SUBJECT MATTER OF THE INVENTION , THE RESULT OF WHICH IS THE "PREMIX" PRODUCT

[0063] In the second step of the process according to the subj ect matter of the invention, a predetermined amount of water is added to the mixture prepared in the first step . According to the solution of the invention, nanoemulsions prepared by the PIC1 technique without a premix were the references in our measurements ( samples referred to as T1KRT and E1KRT ) .

[0064] The other PIC2 method known from the state of the art is slow, as the water must be added slowly throughout to the organic phase .

[0065] At the bicontinuous composition the mixture becomes unmanageably viscous (paste-like ) , both in the laboratory ( it sticks to the stirrer, is not mixed properly) and in production ( di f ferent viscosities require di f ferent rotational speeds / mixer types for good homogeneity) . According to the state of the art , to eliminate this , the mixture is heated, alcohols are added, or other viscosity reducers are added . The subj ect matter of the invention further includes , when applying the combined PIC2 / PIC1 technique , that instead of adding the water throughout , a smaller amount of water is added to the organic phase in such a manner that the system does not yet reach the bicontinuous composition, and thereafter the process is switched to the other technique and the mixture is dispersed into the aqueous phase according to the PIC1 method . As a result , more stable emulsions are obtained than i f the PIC1 method were applied alone . The addition o f water increases the hydration of the hydrophilic emulsi fier, thereby reducing the interfacial curvature , which reaches zero upon attainment of the bicontinuous composition . The amount of water must be comparable to the amount of oil .

[0066] Based on the solution according to the invention, water corresponding to hal f of the mass of the oil is added to the oily phase , thereby confirming that the stability of the triglyceride nanoemulsion prepared from the premix is better, as also confirmed by the triglyceride and essential oil measurement results shown in Graphs 16-19 : in the comparison of premix- free ( T1KRT and E1KRT ) and premix-containing samples ( T1ORT and E1ORT ) , this exact oil / water ratio was used for premix preparation in the triglyceride samples .

[0067] According to the subj ect matter of the invention, the more water is added, the closer the system will be to the bicontinuous composition, but the amount of water must be chosen so that the mixture remains manageable / mixable / dosable . According to the invention, the amount of water added depends on the following .

[0068] - For producing a more stable nanoemulsion, i f exclusively the T80 emulsi fier i s used or i f the T80 / T20 ratio is greater than 1 , preferably an amount of water corresponding to hal f of the mass of the oil is suf ficient , or a larger amount may be added, in which case the viscosity increases .

[0069] - For producing a more stable nanoemulsion, i f the T80 / T20 ratio is less than or equal to 1 , then according to the invention preferably an amount of water corresponding to the sum of the masses of the oil and T20 is added . This is close to the bicontinuous composition, and the viscosity of the mixture does not increase excessively due to the higher T20 concentration . This means that the smaller the T80 / T20 ratio , the more water can be added without forming a paste-like gel . The amount of water to be added is not limited to these two relationships ; these are heuristics only, intended to be as close as possible to the bicontinuous composition . According to the invention, the water is added either in a single portion or slowly, the latter increasing the preparation time . These mixtures are mixed without excessive intensity until homogeneous , avoiding the presence of gel fragments . This time ( i f the mixer mixes properly) takes 5-10 minutes . The premix obtained as a result of the second step of the process can also be used for direct use ; the results of the examined samples T1PRE and E1PRE as well as T1PRE* and E1PRE* are shown in the corresponding Graphs 12-15 and in the description under the presentation of the Premix stability tests ( the tap-water samples are the asterisked ones ) .

[0070] DESCRIPTION OF THE THIRD STEP OF THE PROCESS ACCORDING TO THE SUBJECT MATTER OF THE INVENTION , THE RESULT OF WHICH IS THE NANOEMULSION

[0071] In the third step according to the subj ect matter of the invention, the premix prepared in step 2 is added to the aqueous phase and / or water in the manner detailed below . The desired amount of water is measured so that a nanoemulsion of appropriate concentration can be prepared, and the premix is added to the water in a thin but steady stream under continuous intensive mixing . This process takes approximately 1-2 minutes . Intensive mixing is required during and after the addition, but the use of a high-speed (high-shear ) homogeniser is not necessary . The premix may also be added more slowly to the water, but this increases the production time , and the use of a homogeniser is also possible , but it is not a condition of the process . After the addition, the mixture is mixed for at least one hour, because a shorter time negatively af fects the stability of the nanoemul sion . For comparability, all samples of the measurement results presented in the description were mixed for one hour . During mixing, the mixer and its position must be selected so as not to introduce air into the system, because then intensive foam formation can be expected . The measurement results were obtained, in the case of the PRE and PRE* samples , by examining nanoemulsions prepared from 1- and 4-week premixes with deionised water using the procedure described for step 3 , and from a 4-week premix with tap water and manual mixing; all other samples were prepared from freshly prepared premixes .

[0072] The nanoemulsion thus obtained can also be used for direct use .

[0073] The subj ect matter of the invention further includes that the nanoemulsion is prepared by using a mixture of several oils by the process according to the invention, i . e . the premix used in the third step is prepared by pre-mixing several oils and this is then added to the water .

[0074] The subj ect matter of the invention further includes that i f the oils cannot be pre-mixed, then by the process according to the invention the premix used in the third step is prepared separately for each oil , and then one premix is added to the water to prepare an intermediate nanoemulsion, and the premix prepared from the other oil is added to the resulting intermediate nanoemulsion to obtain the final nanoemulsion . DESCRIPTION OF THE FOURTH STEP OF THE PROCESS ACCORDING TO THE SUBJECT MATTER OF THE INVENTION , THE RESULT OF WHICH IS THE NANOEMULSION END-USE PRODUCT

[0075] For preparing the nanoemulsion end-use product , the following additives may be added to the nanoemulsion prepared in the third step, without limiting the scope of protection to these additives :

[0076] - water-soluble functional components may be added to the prepared nanoemulsion, preferably alcohol , particularly preferably glycerine , gelling agents may be added, or the nanoemulsion may be further diluted with water . Upon dilution, intensive mixing is no longer necessary . The stability of the nanoemulsion solution according to the subj ect matter of the invention was examined as a function of various treatments and changes— cooling, heating, acid / base treatment and scale-up— whereby the results show that it has adequate stability for the industrial-scale production of various nanoemulsion end-use products .

[0077] The subj ect matter of the invention further includes , preferably, the use of the base materials grouped below in the four process steps according to the subj ect matter of the invention, depending on the intended field of use .

[0078] The subj ect matter of the invention further includes , preferably, the use of the base materials grouped below in the four process steps according to the subj ect matter of the invention, depending on the intended field of use .

[0079] COSMETIC INDUSTRY

[0080] For preparing cosmetic nanoemulsion end-use products , preferably skin care , wound treatment and hair care end-use products , the apolar base materials required according to the invention may preferably comprise

[0081] - any oil used in the cosmetic industry, preferably oils containing a large amount of triglycerides and therefore referred to as triglycerides , particularly preferably walnut oil , grape seed oil , argan oil , coconut oil , olive oil and rosehip seed oil ;

[0082] - or further preferably any essential oil used in the cosmetic industry, meaning any fragrance-containing, water-insoluble oil , particularly preferably lavender oil , lemon oil , j asmine oil and rose oil ; and

[0083] - further apolar substances or cosmetic base materials having similar physical properties , particularly preferably vitamin E , coenzyme Q10 , plant extracts , particularly preferably Acmella extract .

[0084] The subj ect matter of the invention further includes that , in step 4 , the base materials listed below are added to the nanoemulsion produced in step 3 depending on the intended use, for the purpose of converting it into a cosmetic nanoemulsion end-use product :

[0085] - further aqueous-based excipients / active agents that are water-soluble , water-miscible or capable of interacting with water ;

[0086] - depending on the desired form of appearance and rheological and other properties , any cosmetic active agents and excipients , preferably gelling agents , preservatives , vitamins , and monohydric or polyhydric alcohols of any carbon chain length, preferably glycerine , ethanol , isopropanol and benzyl alcohol .

[0087] In this case , the nanoemulsion end-use product is not identical to the nanoemulsion; therefore , the alcohol is not a formulation aid required for producing the nanoemulsion, but may be a base material or excipient of the end-use product containing the given nanoemulsion . FOOD INDUSTRY:

[0088] Food-industry hydrophobic nutrients, end products or excipients, preferably flavourings, lipids, preservatives and vitamins, as apolar base materials required for producing nanoemulsion end-use products, may according to the invention preferably be oil-soluble food-industry active agents, particularly preferably vitamins A, D and E, carotenoids, lycopene, lutein, curcumin, resveratrol and CBD. The subject matter of the invention further includes that a large part of these compounds is introduced into the emulsion dissolved in a carrier oil, preferably flaxseed oil, olive oil, corn oil and hemp seed oil. The subject matter of the invention further includes that the carrier oil, preferably lemon oil, is in itself an active agent .

[0089] The subject matter of the invention further includes that the nanoemulsion formed in step 3 can be used directly in the food industry on its own, or the nanoemulsion is converted into a food-industry nanoemulsion end-use product depending on the desired form of appearance and rheological and other properties by adding any food-industry active agents and excipients, preferably stabilisers, texture modifiers, polymers or pH-adjusting agents, in accordance with the intended use.

[0090] PLANT PROTECTION INDUSTRY:

[0091] Apolar base materials required for producing plant protection agents as nanoemulsion end-use products may according to the invention preferably be - essential oils, preferably cinnamon, peppermint, thyme, geranium, lemon, lemon balm, eucalyptus and tea tree essential oils due to their antibacterial or antifungal effects; or preferably marjoram and thyme essential oils for inhibiting the growth of undesirable weeds; - or preferably spearmint and garlic essential oils for protection against pests .

[0092] The subj ect matter of the invention further includes that essential oils , preferably pine oil , may function on their own as carrier oils , thereby enabling synergy with synthetic agents soluble therein .

[0093] The subj ect matter of the invention further includes that , during the process according to the invention, the triglyceride and essential oil nanoemulsion premix prepared in step 2 can be used on its own as a plant protection concentrate , from which, prior to use , the nanoemulsion is prepared by aqueous dilution to the required concentration, preferably by manual mixing or by means of mixers of field sprayers , optionally using tap water, whereby the nanoemulsion can thus be used as a plant protection agent due to its simple , on-site preparation in the manner according to the subj ect matter of the invention .

[0094] The droplet si ze of the nanoemulsion prepared in this manner is preferably less than 30 nm and it remains stable for several days .

[0095] PHARMACEUTICAL INDUSTRY :

[0096] Apolar base materials required for producing medicines and medicinal preparations as nanoemulsion end-use products may according to the invention preferably be semi-synthetic oily esters , triglycerides and partial glycerides . The main factor to be considered when selecting suitable excipients for l ipid formulations is that they are capable of dissolving the entire dose in a volume appropriate for unit oral administration . The type and concentration of the oilemulsi fier mixture , the proportion of the emulsi fier, and the carriers or the temperature conditions of preparation play an important role in emulsi fication . Excipients should be selected from the US FDA "GRAS" ( generally recognised as safe ) list of excipients or from other inactive ingredients permitted and published by regulatory bodies. Drug release properties must not change during the shelf life of the formulation, and the drug must be both physically and chemically stable in the formulation. In commercial parenteral preparations, for example polyoxyl 35 castor oil (Cremophor EL) and sodium deoxycholate (bile salt) are used as emulsifiers. Other commonly used products include Solutol HS-15 (polyoxyethylene-660-hydroxystearate) , polyoxyethylene (20) sorbitan fatty acid esters 20, 40, 60 and 80 (Tween) , sorbitan fatty acid esters 20, 40, 60 and 80 (Span) , and others. As carrier oils, for example coconut oil, sesame oil, cottonseed oil and vitamin E (D-tocopherol ) , and for parenteral and oral administration oleic acid and ethyl oleate are used. In addition, numerous synthetic lipids may be used for preparing nanoemulsions, such as Caproyl 90, triacetin, isopropyl myristate, oleic acid, palm oil esters, corn oil, olive oil, isopropyl palmitate, Labrafil MM44 CS, Maisine 35-1, Miglyol 812, Captex 200.

[0097] (Nanoemulsion: An Emerging Novel Technology for Improving the Bioavailability of Drugs - Preeti , Sharda Sambhakar, Rohit Malik, Saurabh Bhatia, Ahmed Al Harrasi, Chanchai Rani, Renu

[0098] Saharan, Suresh Kumar, Geeta, Renu Sehrawat)

[0099] II. BACKGROUND, STATE OF THE ART, TECHNICAL CONTEXT

[0100] BACKGROUND

[0101] The droplet size range of nanoemulsions generally lies between 20 and 100 nanometres. These ultrafine emulsions are colloidal systems in which one liquid is dispersed in another in the form of tiny droplets. The advantage of the nanoscale is that it creates a more stable system and improves bioavailability, for example in the case of pharmaceutical active agents or in cosmetic preparations. Key characteristics:

[0102] • Droplet size: 20-100 nm.

[0103] • Transparency: often transparent or translucent due to the small size.

[0104] • Stability: higher stability compared to conventional emulsions .

[0105] • Fields of use: pharmaceutical industry, cosmetics, food industry .

[0106] Nanoemulsions are considered classical liquid emulsions consisting of two immiscible liquids. Small spherical droplets (d < 100 nm) can be formed from oil and water without the addition of surfactants. However, this system becomes very unstable; therefore, most nanoemulsions require the use of surfactants (often more than one surfactant) to facilitate droplet formation. Oil (0) , water (W) and surfactants (E) are the three main components of the emulsion. In the present case, an O / W nanoemulsion is concerned, in which the oil is the dispersed phase and the water is the continuous phase. Droplets of the order of a few tens of nanometres are unstable due to the large pressure difference inside and outside the curved interface. The presence of polydispersity in droplet size leads to differences in chemical potential, which promotes mass transfer between droplets. However, with a suitable stabilising polymer layer or surfactant, the required repulsive barrier (electrostatic, steric, etc.) against coalescence can be achieved. With adequate knowledge of surfactant properties, stable nanodispersions can be efficiently produced for a given combination of dispersed and continuous phases. Such systems are of great research interest in the food, pharmaceutical, agrochemical, cosmetic and other industries, with the following advantages. They generally show better stability against particle aggregation and possible sedimentation. Due to the sufficiently small droplet size, they scatter light waves only weakly, and are therefore advantageous where the product must be optically transparent. The biological accessibility of bioactive molecules present in the dispersed phase, potentially of specific types, is much higher .

[0107] (Koh Kai Seng and Wong Voon Loong: Nanoemulsions - Properties , Fabrications and Applications)

[0108] (Kaustav Bhattacharj ee : Importance of Surface Energy in Nanoemulsion) Nanoemulsions are widely used in cosmetic preparations as drug delivery techniques because they are capable of dissolving non-polar active agents. Several large cosmetic companies have begun investing in different nanoemulsion preparation processes, and some products are already on the market. However, further investigation of nanoemulsion systems is required, especially with regard to surfactant-free systems. Another very typical purpose of nanoemulsions is masking the unpleasant taste of oily liquids, and a nanoemulsion may also protect medicines that are sensitive to oxidation and hydrolysis. It is useful in transdermal drug delivery systems because it penetrates the skin barrier excellently and causes minimal irritation. Due to its submicron particle diameter and other advantages, an effective nanoemulsion delivery method used in cosmetics can also be applied in other areas, such as the food and pharmaceutical industries, beverage production and other sectors.

[0109] (A METICULOUS ACCOUNT ON NANOEMULSION IN SKINCARE: APPLICATION TO RECENT DEVELOPMENT : R. S. Pawar, S. V. Khairnar and A. P. Pratap)

[0110] Nanoemulsions can be converted into various dosage forms, such as liquids, creams, sprays, gels, aerosols and foams; and can be administered in an equally diverse manner. They have a higher solubilisation capacity than simple micellar dispersions, and are used in the cosmetic and pesticide industries as aqueous bases for organic materials. Their long- term physical stability is a direct consequence of the small droplet size. It has been reported that many nanoemulsions undergo direct lymphatic absorption, thereby avoiding first- pass metabolism in order to improve bioavailability and reduce the dose of drugs that are extensively transformed in the liver. The components used for developing nanoemulsions must also be strictly non-toxic if intended for human use. (Yuvraj Singh, Jaya Gopal Meher, Kavit Raval , Farooq All Khan, Mohini Chaurasia, Nitin K. Jain, Manish K. Chourasia: Nanoemulsion: Concepts , development and applications in drug delivery) Microemulsions and nanoemulsions have great potential to enhance transdermal permeation of drugs. There are already numerous commercial products that use both natural and synthetic materials as emulsions. Among the various applications, the cosmetic industry stands out as the main supplier of emulsion-based products, where anti-ageing, cleansing, moisturising or anti-wrinkle creams represent most of the consumer demand.

[0111] (Eliana B. Souto, Amanda Cano, Carlos Martins-Gomes , Tiago E. Coutinho, Aleksandra Zieli ska and Amelia M. Silva: Microemulsions and. Nanoemulsions in Skin Drug Delivery) Currently, the market for nanotechnology products in the food industry is approaching USD 1 billion (most of which is nanoparticle-coated packaging technologies, health-improving products and beverages) . Much of the work carried out by research groups in recent years on nanoparticle carriers has focused on developing manufacturing methods based on pharmaceutical drug delivery systems. The challenge in developing such manufacturing methods was to replace some of the polymers and surfactants used in the pharmaceutical industry with food-grade alternatives.

[0112] (Edgar Acosta: Bioavailability of nanoparticles in nutrient and nutraceutical delivery) Fungal pathogens cause signi ficant reductions in crop yield . Therefore , there is a need to develop green, environmentally friendly and safe fungicidal formulations . The toxic ef fects of conventional fungicides on organisms and the environment are a maj or cause for concern . Research has confirmed the anti fungal ef fect of the examined oil nanoemulsions and has suggested that they may be used for biological control against the fungus Botrytis cinerea . Although various synthetic preservatives are often used to maintain food safety, their negative ef fects on health and the environment highlight the need to find safer alternatives . Currently, some plant-based preparations have proven their signi ficance as green preservatives in increasing the shel f li fe of foods . Among plant-based preparations , the use of essential oils has attracted considerable interest in the food industry due to their environmentally friendly and safer properties . (Kamel A. Abd-El salam : Nano fungicides)

[0113] The nanoemulsion was developed as a dispersion system to increase the bioavailability of the essential oil . It was observed that the given essential oil was very promising in terms of larvicidal activity, both under controlled conditions and in the field . Essential oils , either isolated or in synergistic mixtures , may provide an alternative in pest control because they are biodegradable and selective . They become inexpensive , environmentally friendly formulations , which are fairly ef fective in combating pests , particularly when using low-energy and organic-solvent- free delivery methods .

[0114] (Camila Aline Romano, Jeronimo Ralmundo de Oli veira Neto, Lui z Carl os da Cunha , Adelalr Helena dos Santos , Jose Reallno de Paula : Essential oil-based nanoemulsion of Murraya koenigii is an efficient larvicidal against Aedes aegypti under field conditions) TECHNICAL CONTEXT , KNOWN METHODS FOR PREPARING NANOEMULSIONS

[0115] The preparation of a nanoemulsion depends on the energy introduced into the system . Both low- and high-energy techniques have been developed for producing nanoemulsions . Low-energy emulsi fication techniques commonly used in the cosmetic and pharmaceutical industries include the phase inversion temperature ( PIT ) or the phase inversion composition ( PIC ) . Energy input is required to produce a nanoemulsion even though it is a spontaneous process . The amount of energy input essential for producing nanoemulsions is mainly related to the increase in surface area, resulting in interfacial tension and the formation of new droplets . A critical aspect in producing nanoemulsions is achieving extremely low interfacial tension at the ( 0 / W) interface , which requires the appropriate use of surfactants . Surfactants facilitate stabilisation of low- interf acial-tension droplets . The preparation of nanoemulsions can be classi fied into two main categories : low-energy processes and high-energy approaches , based on the process by which energy is introduced into the system to be emulsi fied . Nanoemulsions may be produced by energy input from chemical components and by changing the temperature or composition of the ( 0 / W) system .

[0116] I f a given amount (volume ) of oil is to be dispersed, then by reducing the droplet si ze the total surface area of the droplets increases drastically . Creating smaller droplets increases the interfacial area where emulsi fier, coemulsi fier, etc . molecules are located . Consequently, the minimum or required amount of emulsi fier will also increase . The surf ace / volume ( given amount ) ratio as a function of droplet diameter is theoretically illustrated by the diagram below . Minimum / required emulsifier amount as a function of droplet size

[0117] Experimental evidence of the relationship between emulsifier- to-oil ratio and droplet size

[0118] A COMPARATIVE ANALYSIS OF THE PRIOR ART LITERATURE WITH THE SUBJECT MATTER OF THE INVENTION

[0119] Patent document CN117044776 relates to the preparation of a nanoemulsion in which polysorbate (Tween) emulsifiers are used with ethanol, glycerine and propylene glycol as coemulsifiers. The raw materials are weighed and a high-speed homogeniser is used, and then the nanoemulsion is produced by a high-pressure emulsification technique. The droplet size thereof is approximately 70-90 nm. The (emulsifier + coemulsifier ) / oil ratio is approximately two. In patent document CN116785204, from the raw materials used in the preceding document, the nanoemulsion was prepared in a similar manner, with the difference that ultrasonic homogenisation was selected. The droplet size of the emulsion produced by them is 200+ nm and the (emulsifier + coemulsifier ) / oil ratio is approximately 1.1. In patent document CN116406680, inter alia Tween emulsifiers are also used for preparing a nanoemulsion with n-butanol (alcohol) as a co-emulsif ier . A high-speed homogeniser or ultrasonic homogenisation is used. Their result is a droplet size of 150+ nm .

[0120] In patent document CN116421731, emulsifiers of the Tween series are also used, and, in addition, smaller alcohols such as ethanol, propylene glycol and glycerine are used as coemulsifiers. Their order of preparation is as follows: the oily phase is mixed with the emulsifiers and co-emulsif iers, then an equal volume of water is mixed thereto and, in some embodiments, a high-pressure homogeniser is used, and then the mixture is further diluted. The entire process is carried out at 30-56 °C.

[0121] The solution according to the subject matter of the invention does not require high-energy equipment, heat input, solvents or alcohols, large amounts of emulsifier, or long production time; the process according to the invention is more timeefficient and faster, and provides a smaller droplet size than the prior art solutions described above.

[0122] Patent document US20230201087 uses Tween 80 for producing a nanoemulsion with a co-emulsif ier alcohol having at least 3 carbon atoms. The emulsifiers are mixed with the oil, and then added into water under intensive mixing / phase contact. Their result is, according to their statement, approximately 20 nm, with an opalescent appearance. Their (emulsifier + co- emulsif ier ) / oil ratio is less than 2. Patent document W02023162101 proceeds similarly to the preceding document. A polyhydric alcohol (5-30%) , three emulsifiers and the oils are mixed, and this is dispersed in water using a simple stirrer. This method resulted in a nanoemulsion having a droplet size of 50+ nm.

[0123] In contrast to the solutions described in the two patent documents, the solution according to the subject matter of the invention does not use monohydric or polyhydric alcohols of any carbon chain length.

[0124] Patent documents WO2023139907 and W02021005676 also use polysorbates as emulsifiers, which are mixed with an oil, and the mixture is then dispersed in water, or vice versa. The examples show that this step is carried out at 60-70 °C, followed by rapid cooling. Their emulsif ier / oil ratio is 2.5- 6.5; the achieved droplet size is smaller than 30 nm. Patent documents W01999011240, W01994006310 and WO1997010725 use Tween and Span emulsifiers in their process, where the microemulsion is formed at 140 °C and then rapidly cooled.

[0125] The solutions described above are typical examples of the PIT method; the solution according to the invention does not use this method, but uses the PIC method.

[0126] Patent document CN104874305 uses a non-ionic emulsifier, which is mixed with oil, to which water is added dropwise while stirring slowly at 25-55 °C, thereby resulting in a nanoemulsion. Their emulsif ier / oil ratio is approximately 0.4, whereas their droplet size is 50-100 nm.

[0127] The solution of the cited patent document is a typical phase inversion technique, being slow due to dropwise addition and resulting in a large droplet size. The solution according to the invention is faster and results in a smaller droplet size. Patent document WO2015066777 produces an oil-in-water nanoemulsion using fatty alcohols, monoalcohols and polyols as co-emulsif iers . The emulsifiers are mixed with the oil at 70 °C, and then a small amount of water is added. Thereafter, the remaining required water is added slowly after cooling to 45 °C. According to their example, their emulsif ier / oil ratio is 4.5 and their average droplet size is 20-80 nm.

[0128] The solution of the cited patent document is a combination of the PIT method and phase inversion. With less or the same amount of emulsifier, the process according to the invention achieved a smaller droplet size at ambient temperature. Patent document W02020250252 uses Tween 20 , 40 and 80 and other emulsi fiers with glycerine and propylene glycol as coemulsi fiers . Both the oily phase and the aqueous phase contain emulsi fier and co-emulsi f ier . The oily phase is titrated with the aqueous phase . With this process , a droplet si ze of 15 ± 10 nm was achieved . Their emulsi f ier / oil ratio is 10-14 .

[0129] The solution of the cited patent document is a spontaneous emulsion technique . The process according to the invention requires much less emulsi fier to achieve a droplet si ze of approximately this magnitude ; furthermore , it is not necessary to add anything to the aqueous phase , which also accelerates the process to obtain a small-droplet-si ze emulsion . The titration is also a slow process , which is not required for the process according to the invention .

[0130] Patent document US20150174067 produces a microemulsion and its preconcentrate using Tween 80 and coconut oil . The coconut oil may also contain a dissolved active agent . Their emulsi f ier / oil (E / O) ratio is 4-9 . A mixture of this ratio is the preconcentrate , which contains only these two materials . This preconcentrate is dispersed in water to form the microemulsion . At an E / O ratio of 4 , they observed deterioration over time . The droplet si ze at preparation of the active-agent-containing emulsions was 45- 60 nm .

[0131] Similarly to the solution of the cited patent document , a coconut oil emul sion containing a dissolved substance was also prepared by the process according to the invention, but the result was a much smaller droplet si ze when working at an E / O ratio of 4 . Inter alia, the process according to the invention is intended to eliminate the time-dependent "deterioration" occurring at smaller ratios in the case of triglycerides .

[0132] Patent document EP2384188 produces a microemulsion using a mixture of Tween 20 and Tween 80 with triacetin, which is used as a polarity modi fier, and ethanol or DME as a co-emulsi f ier . These constituents are mixed with the active agent , and then water is added thereto in several portions (without speci fying the portion si zes ) at ambient temperature . The ratio of the amount of emulsi fiers and excipients to the active agent is 14 .

[0133] Although the solution of the cited patent document uses a phase inversion technique , compared to the process according to the invention it uses overall much more excipient as coemulsi fier, including ethanol and triacetin as a polarity modi fier .

[0134] Patent document W02021245001 produces a microemulsion from emulsi fier, oil and polysaccharide base materials . Water is added to the mixture over 0 . 5-3 hours . They may also use alcohol as a co-emulsi f ier . In addition, they use a crosslinking agent , which is related to stability ( also according to their statement ) .

[0135] Although the solution of the cited patent document uses a phase inversion technique , compared to the cited patent document the process according to the invention does not use a polysaccharide for producing the emulsion, and results in a stable emulsion even without a crosslinking agent .

[0136] Patent document W02022029604 produces a microemulsion using Tween 80 and acetone / ethanol in the oily phase , which is evaporated from it at the end of the process . In addition, PVA or PEG is used in the aqueous phase . The oily phase is added to the aqueous phase while stirring slowly at ambient temperature . Their average droplet si ze is 83 . 19 nm .

[0137] The solution of the cited patent document is a solvent-based spontaneous emulsion technique . With the process according to the invention, a much smaller droplet si ze can be achieved .

[0138] Patent document WO2016182926 discloses a nanoemulsion preparation process using Tween 80 , PEG400 and alcohol in the oily phase . The oily phase is dispersed slowly in water, or vice versa . They achieve an extremely small droplet si ze , but they mix for a very long time after dispersion (hours , days ) . The process according to the invention is much faster and more time-efficient and does not use alcohol as an excipient.

[0139] IV. TABULATED SUMMARY OF THE STABILITY OF NANOEMULSION SAMPLES PREPARED IN THE THIRD STEP OF THE PROCESS ACCORDING TO THE INVENTION AFTER DIFFERENT TREATMENTS AND CHANGES

[0140] 1. The stability of the nanoemulsion prepared in the third step of the process according to the subject matter of the invention was examined, considering further transformations in the fourth step, as a function of various changes and treatments.

[0141] The treatments and changes were: cooling, heating, acid / base treatment, and scale-up.

[0142] 2. For the nanoemulsion test samples, O / W nanoemulsions were prepared from triglycerides and essential oils in 100 g amounts, and the oil content of the samples was in all cases 3 wt%.

[0143] 3. In both cases, samples were formulated from 3 different oils, oil mixtures or oil-dissolved active agents, and their stability was tested at ambient temperature, and then, selecting one oil each (T1 and El) , the refrigerated (approximately 2-10 °C) and 45 °C storage stability was tested on separately formulated samples, the pH tolerance was tested at ambient temperature on one acid- and one base-treated sample, the production process was scaled up to 10 kg (approximately 10 L) , and premixes of the selected oils were formulated and their ambienttemperature stability was tested.

[0144] The method of the invention was compared with the known PIC1 process without premix preparation, using one triglyceride sample and one essential oil sample, which were formulated in both ways.

[0145] The oils used and Tween 80 (T80) were purchased from the Humanity webshop, and Tween 20 (T20) was purchased from the E-NATURALNE webshop. As water, deionised water obtainable in retail stores was used. The compositions of the oils, (active) agents used during the study and the nanoemulsions and samples formulated therefrom were summarised in Table 1, the characterisations and explanations of the triglyceride nanoemulsions and samples were summarised in Table 2, and the characterisations of the essential oil nanoemulsions and samples were summarised in Table 3, in Figures 1-2.

[0146] MEASUREMENT PARAMETERS

[0147] The samples were monitored weekly for four weeks. For their characterisation and stability testing, dynamic light scattering (DLS) was used with a Malvern Zetasizer Nano ZS (Serial Number: MAL1020402) , during which the average hydrodynamic diameter (Z-Average) and polydispersity index (PDI) of the nanoemulsions were examined. The measurement was carried out at 25 °C. The DLS measurements were performed by Bay Zoltan Kdzhasznu Nonprofit Kft.

[0148] Some of the measurement reports prepared by them are shown in Figures 3-8, which are the measurement results of the following samples: freshly formulated E1ORT and T1ORT start samples, 4 -week El ORT and T1ORT samples, 1-week T1OH sample and 2-week T3PO sample.

[0149] In addition, regular visual observations were carried out on sample amounts of approximately 15-20 ml. After week 5 from formulation, the nanoemulsions were subjected to a centrifugation test using a Heraeus Megafuge 16, serial number 41399922, Thermo Fisher Scientific, during which they were centrifuged at 8500 rpm for 20 minutes. For nanoemulsions that were still stable after 4 weeks (1 month) , the stability (DLS) test was repeated after 5 months. MEASUREMENT RESULTS OF FRESHLY FORMULATED (START) NANOEMULSIONS

[0150] The average droplet size, hydrodynamic diameter, of all freshly formulated nanoemulsion samples prepared by the proprietary method, not treated with acid / base and not yet subjected to heat treatment, is < 30 nm. The triglyceride samples and their designations are: T1ORT, T1OC, T1OH, T2ORT, T3PO, TIO(IOL) . The essential oil samples and their designations are: E1ORT, EIOC, E1OH, E2ORT, E(1 / 3)O, EIO(IOL) . The samples are clear, transparent solutions with colourless, pale or intensely yellow colour. The average droplet size, hydrodynamic diameter, of all freshly formulated 100 g (approximately 100 ml) triglyceride nanoemulsions prepared by the proprietary method, not yet treated with acid / base, namely T1ORT, T2ORT, T3PO, T1OC and T1OH, is < 20 nm, more preferably < 17 nm, and the average distribution of the hydrodynamic diameters is 17.00 ± 1.65 nm. Their PDI is < 0.34, more preferably < 0.28. The Start measurement report of the freshly formulated T1ORT sample is shown in Figure 3. The droplet size, hydrodynamic diameter, of the scaled-up 10 kg (approximately 10 L) triglyceride nanoemulsion (TIO(IOL) ) is < 30 nm and its PDI is < 0.42. The average hydrodynamic diameter of all freshly formulated 100 g (approximately 100 ml) essential oil nanoemulsions prepared by the proprietary method, not yet treated with acid / base, namely E1ORT, E2ORT, E (1 / 3)0, EIOC and E1OH, is < 15 nm, more preferably < 12 nm, and the average distribution of the hydrodynamic diameters is 11.22 ± 0.79 nm. Their PDI is < 0.27, more preferably < 0.25. The Start measurement report of the freshly formulated E1ORT sample is shown in Figure 4. The scaled-up 10 kg (approximately 10 L) essential-oil nanoemulsion (EIO(IOL) ) has a hydrodynamic diameter of < 15 nm and a PDI of < 0.28.

[0151] STABILITY OF STORED NANOEMULSION SAMPLES AND GRAPHICAL SUMMARY STABILITY OF STORAGE AT AMBIENT TEMPERATURE Triglyceride samples: T3PO:

[0152] After 4 weeks, among the triglyceride ambient-temperature storage samples (T1ORT; T2ORT; T3PO) , only the propolis- saturated coconut oil (T3PO) showed slight deterioration, however its hydrodynamic diameter remained < 30 nm after 4 weeks. During the centrifugation test performed in week 5, no precipitation was visible. After 5 months, the T3PO sample showed slight turbidity and a further increase in droplet size, with a hydrodynamic diameter of < 80 nm and a PDI of < 0.25; however, it still remained within the nanoemulsion size range .

[0153] The measurement report of the T3PO sample stored for 2 weeks is shown in Figure 5.

[0154] T1ORT and T2ORT:

[0155] The other ambient-temperature samples (T1ORT and T2ORT) showed no signs of deterioration after 4 weeks; their particle size and PDI were stable and closely matched the start measurements: hydrodynamic diameter < 20 nm, more preferably < 17 nm, PDI < 0.28.

[0156] The measurement report of the T1ORT sample stored for 4 weeks is shown in Figure 6.

[0157] By visual observation, after week 4 and after 5 months, all samples remained clear and transparent; during the centrifugation test performed in week 5, no precipitation was visible in any of them.

[0158] These samples did not show significant deterioration even after 5 months. Their hydrodynamic diameter was < 30 nm. Their PDI, however, was variable, < 0.46; more preferably < 0.3. This indicates that the droplet size distributions became less uniform and a minimal deterioration of solution quality commenced .

[0159] The measurement results as a function of time are shown in Figure 9, Graph No. 1. Essential-oil samples:

[0160] The essential-oil samples stored at ambient temperature (E1ORT, E2ORT and E (1 / 3)0) showed no signs of deterioration after 4 weeks; their particle size and PDI were stable and closely matched the start measurements: hydrodynamic diameter < 15 nm, PDI < 0.33, more preferably < 0.28. The measurement report of the E1ORT sample stored for 4 weeks is shown in Figure 7.

[0161] By visual observation, after week 4 and after 5 months, all samples remained clear and transparent; during the centrifugation test performed in week 5, no precipitation was visible in any of them.

[0162] These samples did not show significant deterioration even after 5 months. Their hydrodynamic diameter was < 15 nm. Their PDI was < 0.35; more preferably < 0.3. Thus, after 5 months, droplet size remained unchanged and the deterioration observed in the PDI was also minimal.

[0163] The measurement results as a function of time are shown in Figure 9, Graph No. 2.

[0164] STABILITY OF REFRIGERATED STORAGE

[0165] The triglyceride and essential-oil nanoemulsions stored in a refrigerator (approximately 2-10 °C) were stable after 4 weeks; neither showed any deviation from the samples stored at ambient temperature: Z-Average < 20 nm, more preferably < 15 nm, PDI < 0.26. By visual observation, they remained clear, transparent solutions. During the centri fugation test performed in week 5 , very minimal , barely noticeable precipitation was visible at the bottom of the triglyceride sample ; no precipitation occurred in the essential-oil sample .

[0166] After 2 months , however, in the triglyceride ( T1OC ) sample, a clearly visible floating body resembling mould was observed, which was not detected in any other sample . Accordingly, although the emulsion itsel f was stable and a clear solution, further measurements were omitted due to quality deterioration .

[0167] In contrast , the essential-oil (EIOC ) sample showed a high degree of stability even after 5 months , with a hydrodynamic diameter of < 15 nm and a PDI of < 0 . 3 .

[0168] The 5-month measurement results of the essential-oil sample compared with ambient-temperature storage are shown in Figure 9, Graph No . 3.

[0169] The four-week measurement results of the essential-oil and triglyceride samples compared with ambient-temperature storage , as a function of time , are shown in

[0170] Figure 10, Graphs No . 4 and. 5.

[0171] STORAGE STABILITY OF SAMPLES HEATED TO 45 ° C

[0172] For the samples heated to 45 ° C, the essential-oil sample (E1OH) was stable and showed no change compared with ambienttemperature storage .

[0173] The measurement results of the essential-oil sample , compared with the ambient-temperature and refrigerated storage data, as a function of time , are shown in Figure 10, Graph No . 4.

[0174] For the triglyceride sample ( T1OH) , however, already after 1 week a more pronounced droplet si ze increase and clearly visible opalescence were observed, and by the end of week 4 a white , opaque emulsion was obtained, having a hydrodynamic diameter of < 120 nm . The PDI , however, did not increase ; at the end of the study, PDI < 0 . 15 . During the centri fugation test performed in week 5 , minimal precipitation was visible at the bottom; no precipitation occurred in the essential-oil s amp 1 e .

[0175] The slightly opalescent 45 ° C triglyceride sample removed for visual observation after 1 week ( Z-average < 60 nm) , when stored at ambient temperature , did not become more opalescent , did not cream, and showed no signs of degradation . The measurement report of the T1OH sample stored for 1 week is shown in Figure 8.

[0176] The measurement results of the triglyceride samples , compared with the ambient-temperature and refrigerated storage data, as a function of time , are shown in Figure 10, Graph No . 5.

[0177] CONCLUSION OF NANOEMULSION STABILITY AND MEASUREMENT RESULTS

[0178] From the above , it is concluded that , in the long term, the most suitable storage temperature for triglyceride nanoemulsions is ambient temperature , at which they remain stable for 5 months . Heating at 45 ° C can be tolerated for at most a few days without signi ficant damage . Refrigerated storage is tolerated by the emulsions , but in the long term it is recommended only with the use of a suitable preservative . Essential-oil nanoemulsions are more resistant to temperature ef fects : they can be stored stably for 5 months both at ambient temperature and in a refrigerator, and they can also tolerate 45 ° C for at least 1 month without deterioration .

[0179] STABILITY OF ACID- AND BASE-TREATED SAMPLES

[0180] MEASUREMENT PARAMETERS

[0181] For both the triglyceride sample (walnut-oil nanoemulsion, T1ORT ) and the essential-oil sample ( lavender-oil nanoemulsion, E1ORT ) , the pH of one separately formulated 100 g sample was adj usted to approximately 2 . 0 us ing household hydrochloric acid ( T1OAC, E10AC) , and the pH of one separately formulated 100 g sample was adjusted to approximately 12.0 using KOH solution (approximately 50%) (T1OAL, E1OAL) . (The pH measurement was carried out using a Voltcraft PHT-02 ATC manual pH meter. )

[0182] MEASUREMENT RESULTS OF TRIGLYCERIDE SAMPLES

[0183] The original pH of the untreated triglyceride nanoemulsion (prepared from walnut oil) , T1ORT, was approximately 5.9. The pH tolerance of the triglyceride samples was monitored for 2 weeks .

[0184] STABILITY AND MEASUREMENT RESULTS OF ACIDIC AND BASIC SAMPLES Acidification of the triglyceride sample (T10AC) had no effect on either particle size or PDI; after 2 weeks, both remained stable and differed only slightly from the untreated nanoemulsion: Z-Average < 25 nm, more preferably < 20 nm, PDI

[0185] < 0.28.

[0186] Basification of the triglyceride sample (T1OAL) caused, already after 1 week, a slight increase in particle size and a larger increase in PDI; after 2 weeks, Z-average < 25 nm, PDI

[0187] < 0.55, i.e. pH ~12 reduces stability time.

[0188] Visual observation: both when freshly formulated and after 2 weeks, they were clear, transparent liquids. After 4 weeks, however, the acidified sample (T1OAC) showed slight opalescence. On the surface of the basic sample (T1OAL) , small oil droplets were visible.

[0189] The results showed that triglyceride nanoemulsions tolerate acidic medium for approximately 2 weeks, and basic medium for approximately 1 week. The measurement results as a function of time are shown in Figure 11, Graphs No. 6 and. 7. MEASUREMENT RESULTS OF ESSENTIAL-OIL SAMPLES

[0190] The original pH of the untreated essential-oil nanoemulsion (prepared from lavender oil) , E1ORT, was approximately 6.9. The pH tolerance of the essential-oil samples was monitored for 1 week (7 days) .

[0191] STABILITY AND MEASUREMENT RESULTS OF ACIDIC AND BASIC SAMPLES The acidic sample (E10AC) was stable by the end of day 7 and its measured parameters were very similar to those of the untreated sample: Z-Average < 15 nm, PDI < 0.25. The particle size of the basic sample was stable by the end of day 7, but its PDI deteriorated somewhat. At the end of measurement: Z- Average < 15 nm, PDI < 0.40.

[0192] Visual observation: both when freshly formulated and after 1 week, they were clear, transparent liquids. After 4 weeks, however, the acidified sample (E1OAC) completely degraded into a white, opalescent liquid with creamy precipitation on the top .

[0193] On the surface of the basic sample (E1OAL) , small oil droplets were visible after week 4.

[0194] The results showed that essential-oil nanoemulsions tolerate acidic medium for approximately 1-2 weeks, and basic medium for < 1 week.

[0195] The measurement results as a function of time are shown in Figure 12, Graphs No. 8 and. 9.

[0196] STABILITY OF SCALED-UP 10 kg (approximately 10 L) SAMPLES The scaled-up samples were stable for both oil types and remained clear, transparent solutions until the end of the study. During the centrifugation test performed in week 5, no precipitation occurred in the essential-oil sample, while very minimal precipitation was visible in the triglyceride sample. The average particle size and PDI of the essential-oil sample remained very similar to those of the 100 g sample throughout; after 4 weeks and after 5 months , Z-Average < 15 nm and PDI < 0 . 2 .

[0197] The average particle si ze of the triglyceride sample was slightly higher from the outset than that of the 100 g sample , but stable ; by the end of week 4 and after 5 months it was < 30 nm . Its PDI was somewhat higher from the outset than that of the other samples : on the day of formulation < 0 . 42 ; by the end of week 4 and after 5 months also < 0 . 45 . The measurement results as a function of time are shown in

[0198] Figure 13, Graphs No . 10 and 11.

[0199] PREMIX STABILITY STUDY

[0200] Premixes T10RT and E1ORT ( oil + emulsi fier ( s ) + water ) in amounts required for 1-1 nanoemulsion of 3 wt% and 300 g total mass were prepared, stored in sealed glass containers at ambient temperature , and then, after 1 week and after 4 weeks , they were homogenised, sampled and, by mixing into deionised water, 100-100 g of 3 wt% nanoemulsions were prepared ( samples T1PRE and E1PRE ) , which were measured on the day of preparation .

[0201] Thereafter, in week 4 , from the remaining premixes , 1-1 nanoemulsion sample of approximately 95 g and approximately 2 . 3-2 . 4 wt% triglyceride and essential-oil nanoemulsion was formulated, using tap water at ambient temperature instead of deionised water, and manual ( spoon) mixing instead of 1 hour of mechanical stirring, only for as long as the premix became fully mixed and was no longer visually discernible in the emulsion ( samples T1PRE* and E1PRE* ) . The samples were measured on the day of preparation .

[0202] For the triglyceride samples , at week 4 the premix was visually homogeneous , clear, transparent , vivid yellow and viscous ; homogenisation in this case means short manual shaking and rotation of the container .

[0203] For the samples prepared with deionised water and 1 hour of stirring (T1PRE) , the particle size after 1 week and after 4 weeks was < 25 nm, PDI < 0.42, more preferably < 0.30. Slightly opalescent, transparent liquids. During the centrifugation test performed in week 5, the sample formulated in week 4 was centrifuged, and slight precipitation was visible at the bottom.

[0204] For the sample prepared with tap water and manual mixing (T1PRE*) , the mixing time was approximately 17 minutes (15-20 minutes) , during which the premix pieces were fully dispersed. Visually: slightly opalescent, transparent / translucent liquid, having a hydrodynamic diameter of < 30 nm and PDI < 0.6. The system thus prepared is fairly polydisperse, but a nanoemulsion stable for a few days can be prepared by this method. During the centrifugation test performed in week 5, minimal precipitation was visible on the side and at the bottom.

[0205] The measurement results as a function of time are shown in Figure 14, Graphs No. 12 and 13.

[0206] For the essential-oil samples, the premix was a slightly opalescent, colourless, viscous liquid, which separated into two phases after a few days and remained in that state; accordingly, homogenisation in this case means stirring for approximately 2-3 minutes at approximately 300 rpm until the system appears homogeneous.

[0207] For the samples prepared with deionised water and 1 hour of stirring (E1PRE) , the particle size after 1 week and after 4 weeks was < 15 nm, PDI < 0.25, more preferably < 0.23. Colourless, clear, transparent liquids. During the centrifugation test performed in week 5, minimal precipitation was visible at the bottom. Thus, phase separation of the premix does not present a problem for nanoemulsion formulation; however, appropriate homogenisation must be ensured . For the sample prepared with tap water and manual mixing (E1PRE*) , the mixing time was approximately 5 minutes, during which the premix pieces were fully dispersed. Visually: colourless, clear, transparent liquid, having a hydrodynamic diameter of < 15 nm and PDI < 0.2. During the centrifugation test performed in week 5, no precipitation was visible. The measurement results as a function of time are shown in

[0208] Figure 15, Graphs No. 14 and 15.

[0209] COMPARISON OF THE PREMIX METHOD AND THE PIC METHOD WITHOUT PREMIX

[0210] One 100 g, 3 wt% triglyceride (T1KRT) and one essential-oil (E1KRT) sample were prepared by omitting premix preparation, with all other conditions, composition, mixing time, etc. being the same as for the other samples: the oil and emulsifier ( s ) were homogenised by stirring for approximately 5 minutes at approximately 300 rpm, then the mixture (organic phase) was added into the aqueous phase (deionised water) under continuous stirring, and thereafter stirred for 1 hour at approximately 1100 rpm at ambient temperature. In both cases the final result was a clear, transparent liquid, which was monitored for 5 months.

[0211] For the triglyceride sample, the initial particle size was of the same order of magnitude as that of the control sample measured by the proprietary method (T1ORT) . At the end of week 4, Z-Average < 20 nm.

[0212] Although the measurement results did not yet show it, after approximately 3 weeks, on the surface of the T1KRT sample set aside for visual observation, slight creaming was visible, which increased over time; it temporarily disappeared upon mixing, but reappeared by the next day. During the centrifugation test performed in week 5, slight precipitation occurred on the side of the T1KRT sample. For the T1ORT sample prepared by the premix method, neither creaming nor precipitation was observed.

[0213] After 5 months, it is visible that the average hydrodynamic diameter changed only minimally for both T1KRT and T1ORT: for T1ORT < 20 nm; for T1KRT < 25 nm. However, quality deterioration of the sample without premix was already observable after 1 month in the increasingly steep rise of its PDI. After 5 months of storage, the PDI of the premix sample (T1ORT) was < 0.25; the PDI of the non-premix sample (T1KRT) was < 0.35.

[0214] The measurement results as a function of time are shown in Figure 16, Graphs No. 16 and 17.

[0215] It is thus evident that the triglyceride nanoemulsion solution prepared by the process without premix starts to deteriorate significantly faster than that prepared by the premix method. This is visible both visually via creaming and via the more pronounced increase in PDI . Based on the results, it is assumed that, for triglyceride-based nanoemulsions, incorporating premix preparation either promotes longer-term stability of the nanoemulsion or shortens the mixing time required for formation of a stable system. It is possible that with longer (multi-hour) stirring an identical stability could have been achieved; however, this was not tested. For the essential-oil sample (E1KRT) , the particle size was of the same order of magnitude as that of the control sample measured by the proprietary method (E1ORT) and it remained stable throughout the study period. At the beginning of the study, at the end of week 4 and after 5 months, Z-Average < 15 nm. During the centrifugation test performed in week 5, no precipitation was visible in either E1KRT or E1ORT, and the solutions remained clear without turbidity until the end of the study. The PDI of the premix sample (E1ORT) remained stable over the 5 months and PDI < 0.25. The PDI of the non-premix sample (E1KRT) showed variability. At the beginning of the study, PDI < 0.35, then within approximately 1 month it decreased significantly to PDI < 0.2, which is slightly better than the PDI value of the premix sample, and this remained stable until the end of the study.

[0216] Based on the results, it is assumed that for essential-oil nanoemulsions, premix preparation is not necessarily required from a stability standpoint, and omitting it does not affect system stability within the examined time range. At the same time, for triglyceride nanoemulsion production, premix preparation improves long-term stability of the product; thus, in this case its use is strongly recommended. A further advantage of premix preparation is that, during the production process, premix preparation and mixing with the aqueous phase can, if necessary, be separated in time and space, as the premixes themselves are stable for at least 1 month. Furthermore, for example for plant-protection applications, it may be possible to market spray products in premix form, since a nanoemulsion stable for a few days can be prepared from them even by manual mixing. The measurement results as a function of time are shown in Figure 17, Graphs No. 18 and. 19.

[0217] The test results for T1KRT, T1ORT and E1KRT and E1ORT shown in Graphs No. 16-19 demonstrate that the nanoemulsion prepared from premix according to the invention is more stable in the triglyceride variant, and has identical stability in the essential-oil variant, compared with the nanoemulsion prepared by the PIC method without premix.

[0218] REPRODUCIBILITY OF THE MEASUREMENTS

[0219] For the measurements, 100 g batches were formulated separately, on the same day, under identical conditions, as the following 3 + 3 samples prepared according to the same recipe (from the same oil, at the same concentration) . Accordingly, the Start measurements of the ambient (_ORT) , refrigerated (_OC) and 45 °C (_OH) samples are suitable for examining whether performing the process three times in the same way yields the same result.

[0220] The measurement results for the triglyceride and essential-oil samples are summarised in Figure 18, Table No. 4.

[0221] According to the results, the average hydrodynamic diameters are consistent for both the triglyceride and essential-oil samples; any differences may be caused by possible measurement error due to solution concentration and by non-identical distributions (non-identical PDI) . The quantiles, however, clearly show that the formed droplets fall within a given interval .

[0222] VI . Recipes , Embodiments

[0223] The subject matter of the invention is supported by the following embodiments, without limiting the scope of protection to the embodiments.

[0224] 1. Recipe (1) : T1ORT - walnut oil nanoemulsion (100 g, 3 m / m% )

[0225] We weigh 3.0 g of walnut oil and 12.0 g of Tween 80, and homogenise the mixture at room temperature and atmospheric pressure using a magnetic stirrer at ~400 rpm for 5 minutes, then add 1.5 g of deionised water and stir for a further ~5 minutes until no lumps remain and a clear, homogeneous, yellow (foamy) premix is obtained. We measure 83.5 g of water and stir at ~1100 rpm, then add the premix to the stirring water in a continuous stream within ~0.5-l minute, and stir at the same speed for 1 hour. Gel pieces of the premix disappear from the mixture after ~5-10 minutes of stirring. Foaming is to be expected as a result of the intensive stirring. 2. Recipe (2) : E1ORT - lavender oil nanoemulsion (100 g, 3 m / m% )

[0226] We weigh 3.0 g of lavender essential oil, 6.0 g of Tween 80 and 6.0 g of Tween 20. The mixture is homogenised at room temperature and atmospheric pressure using a magnetic stirrer at ~400 rpm for 5 minutes, then 9.0 g of deionised water is added and stirring is continued for a further ~5 minutes until a homogeneous, slightly opalescent, whitish (foamy) premix is obtained. We measure 76.0 g of water and stir at ~1100 rpm, then add the premix to the stirring water in a continuous stream within ~0.5-l minute, and stir at the same speed for 1 hour. The premix pieces disperse immediately after addition. The mixture is initially opalescent and clears after ~10-15 minutes of intensive stirring; foaming is to be expected.

[0227] VI I . Summary

[0228] The essence and advantages of the invention are summarised below .

[0229] ESSENCE OF THE INVENTION:

[0230] The subject matter of the invention is a generally applicable, three-step process for preparing a nanoemulsion having a small droplet size and high stability without the use of a solvent, a special emulsifier, preferably without the use of an alcohol, at room temperature and atmospheric pressure, wherein the water-insoluble apolar materials (oil, etc.) are mixed and stirred with water as specified in the first two steps of the process according to the subject matter of the invention, and the "premix" thus obtained is converted into a nanoemulsion in the third step as specified.

[0231] The subject matter of the invention further includes producing a nanoemulsion end-use product, wherein various further waterbased substances (acid, base, gelling agent, alcohol, etc.) are added to the nanoemulsion solution in a fourth step to obtain, depending on the f ield of application, the nanoemulsion end-use product .

[0232] The nanoemulsion end-use product has numerous possible uses : it can be used as a liquid, as a cosmetic product- , plant care- , insect repellent- spray, as a medicinal product , beverages ; gelled as a gel , so ft gelatin capsule , cosmetic product , medicinal product ; and as the premix produced in step 2 , which nanoemulsion concentrate can be used directly as a plant protection agent (premix mixed with tap water by hand) .

[0233] Thus , the nanoemulsion and the premix can also be used on their own in certain fields of application . The subj ect matter of the invention, and novelty, is that the premix - by dilution to the required concentrations - can be used directly as a plant protection agent .

[0234] GENERAL ADVANTAGES

[0235] 1 . It is emphasised that no alcohol needs to be added for their preparation, which previously formed part of the usual process for preparing a small droplet si ze nanoemulsion solution .

[0236] 2 . The concentration of the nanoemulsion prepared in three steps can be adj usted either during formulation or by subsequent arbitrary dilution of the prepared nanoemulsion ( the extent of dilution being controlled by maintaining ef ficacy) , depending on the intended application .

[0237] 3 . A further advantage is that for preparing the nanoemulsion, there is no need to use a mono- or polyhydric alcohol (with any number of carbon atoms ) as an emulsi fier and / or co-emulsi f ier ; there is also no need to use a high-speed, high-pressure homogeniser or ultrasonic equipment ; all proces ses are performed at room temperature ; the process according to the invention is capable of achieving a much smaller droplet size, and the droplet size can also be maintained upon scale-up.

[0238] 4. The process according to the invention does not require energy-intensive equipment, heat input, solvents or alcohols, a large amount of emulsifier, or a long production time; the process according to the invention is more time-saving and provides better yield than solutions according to the prior art; no special conditions are required; the process is performed at room temperature and atmospheric pressure.

[0239] ADVANTAGES GROUPED BY FIELD OF APPLICATION

[0240] ADVANTAGES OF COSMETIC USE

[0241] Nanoemulsion end-use products can be used in cosmetics on their own as a spray or nanoemulsion gel, but can also be blended into other products, such as creams. They can be found, inter alia, in sunscreens and moisturising creams, serums, makeup base products and hair care products.

[0242] Their increasing popularity in cosmetics is due to their properties that are excellently suitable for cosmetic use: they promote faster absorption of products, so they do not leave a sticky residue on the skin, and active ingredients, due to the small droplet size, are able to penetrate into deeper layers of the skin than in the case of conventional emulsions, thereby being utilised more effectively.

[0243] Highlighting a few examples from studies on efficacy, grape seed oil nanoemulsion is much more effective as an anti-aging agent than macroemulsions, and a nanoemulsion cream containing lavender essential oil significantly accelerates wound healing and re-epithelialisation .

[0244] (The effect of antioxidant of grapeseed oil as skin anti-aging in nanoemulsion and emulsion preparations - Sumaiyah and B.M. Leisyah ; Deep skin wound healing potential of lavender essential oil and licorice extract in a nanoemulsion form: Biochemical, histopathological and gene expression evidences - Maryam Kazemi, Mojgan Mohammad! far , Esmat Aghadavoud, Zarichehr Vakili, Mohammad Hossein Aarabi , Sayyed Alireza Talaei; Cosmetic Nanoemulsion - Uses, Procedure, Risk Factors, and Disadvantages - Dr. Neeta Bhanushali Lalji)

[0245] ADVANTAGES OF FOOD INDUSTRY USE

[0246] As set out above as part of the subject matter of the invention, applying the listed substances in the food industry as nanoemulsions improves their dispersibility in water, their chemical stability, or increases their bioavailability and thus their efficacy. In this field too, nanoemulsions can be prepared in compliance with the applicable regulations, using internally approved emulsifiers, oils and essential oils, and active ingredients. The general process according to the invention and our emulsifiers used (T80 and T20) also comply, in this case, with the criteria prescribed in the industry. The nanoemulsion end-use product prepared by the process tolerates pH values around gastric acid, at which it remains stable for days. When used as a dietary supplement, a wide range of f at / oil-soluble substances can be encapsulated in the nanoemulsion, not only vitamins. The use / applicability is very broad, from which the following research example is highlighted. Lemon oil nanoemulsion has a greater effect on bacteria causing fish spoilage than 100% lemon oil, and thus can potentially be used as a natural antimicrobial agent in the fish processing industry.

[0247] (Antimicrobial influence of nanoemulsified lemon essential oil and pure lemon essential oil on food-borne pathogens and fish spoilage bacteria - Hatice Yazgan, Yesim Ozogul , Esmeray Kuley; Nanoemulsions as delivery systems for lipophilic nutraceuticals : strategies for improving their formulation, stability, functionality and bioavailability - Seung Jun Choi and David Julian McClements)

[0248] ADVANTAGES OF PLANT PROTECTION INDUSTRY USE

[0249] Nanoemulsions are already used in the plant protection industry as carriers of plant protection active ingredients or as efficient delivery systems for agricultural chemicals. These formulations may replace or provide better alternatives to conventional pesticides. Their aim is to improve the water solubility and utilisation of active ingredients, and to prepare sustainable, green and environmentally friendly plant protection agents. The most common form is the use of oil-in- water nanoemulsions. The general advantages of nanoemulsions are also manifested here, such as better release and utilisation of substances due to small droplet size, and protection of the active ingredient against photodegradation as a result of encapsulation. In such formulations, non-ionic emulsifiers are generally used, because they are less affected by ion concentration and pH. Emulsifiers currently used in plant protection agents include Tween 80, Tween 20, Span 80, Span 20, PEG-40 castor oil, and the PEG series. The possibilities for use of nanoemulsion end-use products in the plant protection industry are broad; for example, a higher emergence rate and germination index can be observed in maize if seeds are coated with vitamin E nanoemulsion before sowing.

[0250] (Nanoemulsion seed, invigouration for improved germination and seedling vigour in maize - M Surendhiran, K Raja, Jerlin Regis, Marimuthu Subramanian; Synthesis and Technology of Nanoemulsion-Based Pesticide Formulation - Isshadiba Mustafa , Mohd Zobir Bin Hussein)

[0251] (NanoEmulsion Based Pesticides Formulations -A Bioengineering Perspective - Priyanka Devi, Samuel Prem Math! Maran) ADVANTAGES OF PHARMACEUTICAL USE

[0252] Nanoemulsions are becoming increasingly popular in the pharmaceutical industry due to their high applicability. Their main purpose is to increase solubility and stability, improve bioavailability and better utilisation, which may allow a lower dose of the active ingredient to be sufficient. The active ingredient is enclosed in droplets, which protects it against environmental variables such as oxidation or pH changes; furthermore, it can effectively mask the metallic or bitter taste of medicines, which may cause unpleasant side effects such as nausea and vomiting. Consequently, it can be useful in creating innovative pharmaceutical products. The use of pharmaceutical active ingredients as nanoemulsions can be parenteral, oral, intravenous, intrapulmonary, intranasal and intraocular. In terms of their forms, they may be gels, creams, foams, aerosols and sprays, which facilitate administration .

[0253] They can be applied to pharmaceutical preparations for several diseases, such as high blood pressure, diabetes, cancer treatment, cataract, glaucoma, Alzheimer's disease, migraine, meningitis .

[0254] REFERENCES

[0255] Koh Kai Seng and Wong Voon Loong: Nanoemulsions - Properties,

[0256] Fabrications and Applications, Introductory Chapter: From Microemulsions to Nanoemulsions; 1. Chapt; (2019)

[0257] Kaustav Bhattachar jee : Importance of Surface Energy in

[0258] Nanoemulsion; 6. Chapt.; (2019)

[0259] R. S. Pawar , S. V. Khairnar and A. P. Pratap: A meticulous account on nanoemulsion in skincare: application to recent development (2022) ; Vol. 13 (5) : 1908-1923.

[0260] Yuvraj Singh, Jay a Gopal Meher, Kavit Raval , Farooq Ali Khan, Mohini Chaurasia, Nitin K. Jain, Manish K. Chourasia: Nanoemulsion: Concepts, development and applications in drug delivery (2017) ; Vol. 252: 28-49.

[0261] Eliana B. Souto, Amanda Cano, Carlos Martins -Gomes , Tiago E.

[0262] Coutinho , Aleksandra Zielinska and Amelia M. Silva:

[0263] Microemulsions and Nanoemulsions in Skin Drug Delivery (2022) ; 9(4) : 158.

[0264] Edgar Acosta: Bioavailability of nanoparticles in nutrient and nutraceutical delivery (2009) ; Vol. 14: 3-15.

[0265] Kamel A. Abd-Elsalam: Nanofungicides (2024)

[0266] Camila Aline Romano, Jeronimo Raimundo de Oliveira Neto , Luiz Carlos da Cunha, Adelair Helena dos Santos, Jose Realino de Paula: Essential oil-based nanoemulsion of Murraya koenigii is an efficient larvicidal against Aedes aegypti under field conditions (2024) ; Vol. 208: 117836 Abeeda Mushtaq, Sajad Mohd Wani , A.R. Malik, Amir Gull, Seema Ramniwas , Gulzar Ahmad Nayik, Sezai Ercisli, Romina Alina Marc, Riaz Ullah, Ahmed Bari: Recent insights into Nanoemulsions: Their preparation, properties and applications (2023) ; 18: 100684.

[0267] Sumaiyah and B.M. Leisyah: The effect of antioxidant of grapeseed oil as skin anti-aging in nanoemulsion and emulsion preparations (2019) ; Vol. 12: 1185-1194

[0268] Maryam Kazemi, Mojgan Mohammadifar , Esmat Aghadavoud, Zarichehr Vakili, Mohammad Hossein Aarabi , Sayyed Alireza Talaei : Deep skin wound healing potential of lavender essential oil and licorice extract in a nanoemulsion form: Biochemical, histopathological and gene expression evidences (2020) ; Vol. 29: 116-124.

[0269] Dr. Neeta Bhanushali Lalji: Cosmetic Nanoemulsion - Uses, Procedure, Risk Factors, and Disadvantages (2022)

[0270] Hatice Yazgan, Yesim Ozogul , Esmeray Kuley: Antimicrobial influence of nanoemulsified lemon essential oil and pure lemon essential oil on food-borne pathogens and fish spoilage bacteria (2019) ; Vol. 306: 108266

[0271] Seung Jun Choi and David Julian McClements : Nanoemulsions as delivery systems for lipophilic nutraceuticals: strategies for improving their formulation, stability, functionality and bioavailability (2020) ; 29(2) : 149-168.

[0272] M Surendhiran, K Raja, Jerlin Regis, Marimuthu Subramanian:

[0273] Nano emulsion seed invigouration for improved germination and seedling vigour in maize (2019) ; Vol. 9: 333-340. Isshadiba Mustafa, Mohd Zobir Bin Hussein: Synthesis and Technology of Nanoemulsion-Based Pesticide Formulation (2020) ; 10 (8) : 1608.

[0274] Priyanka Devi, Samuel Prem Mathi Maran: Nano Emulsion Based Pesticides Formulations-A Bioengineering Perspective (2023) ; Vol. 7: 50-59.

[0275] Preeti , Sharda Sambhakar, Rohit Malik, Saurabh Bhatia, Ahmed Al Harrasi , Chanchai Rani, Renu Saharan, Suresh Kumar, Geeta, Renu Sehrawat: Nanoemulsion: An Emerging Novel Technology for Improving the Bioavailability of Drugs (2023) ; 6640103.

Claims

CLAIMS1. An industrially feasible, economical, generally applicable, three-step process the preparation a highly stable nanoemulsion having a small droplet size, preferably below 30 nm, by a phase inversion composition (PIC) method, wherein the process is characterised in that- no organic solvent, preferably no alcohol, is employed as an emulsifier or as a formulation aid for achieving the small droplet size, and- the process is carried out at ambient temperature and at atmospheric pressure, in such a manner that:(a) as a first step, apolar materials, namely one or more oils, are homogenised with one or more emulsifiers for several minutes while setting an appropriate emulsif ier-to-oil (E / O) ratio ;(b) as a second step, a predetermined amount of water is added in a single portion to the mixture obtained in the first step and the resulting mixture is homogenised for 5-10 minutes, preferably until it becomes visually completely homogeneous, whereby the viscosity of the resulting mixture, referred to as a premix, increases and the premix undergoes a slight temperature rise;(c) as a third step, the nanoemulsion is produced by dispersing the premix in water in such a way that the dispersion of the premix is carried out, independently of scale, under intensive mixing and phase contact for a period of less than 1-2 minutes, followed by continuous mixing of the mixture for one hour, such that the total preparation time of the nanoemulsion is approximately 1.5 hours.

2. The process according to claim 1, wherein during the process, one or more materials selected from the groups listed and classified below are used and / or may be added, without limiting the scope of protection thereto :Water- deionised water, as used in the experiments,- distilled water, ultrapure water or other purified water,- tap water or water containing dissolved salts, particularly for mixing with the premix.Emulsifiers, surfactants and co-surf actants- preferably polysorbate 80 (Tween 80, T80; polyoxyethylene ( 20 ) sorbitan monooleate) ;- preferably polysorbate 20 (Tween 20, T20; polyoxyethylene ( 20 ) sorbitan monolaurate) ;- other polyoxyethylene sorbitan fatty acid esters, preferably polysorbate 40, polysorbate 60, polysorbate 65 and polysorbate 85;- polyethylene glycols, preferably PEG-400, PEG-600, PEG-800,PEG-1000 and PEG-2000;- sorbitan fatty acid esters, preferably Span 20 and Span 60;- other emulsifiers known from the prior art.Oils - essential oils and essential oil mixtures- preferably lavender oil, lemon oil, peppermint oil, rose oil, pine oil, clove oil, rosemary oil and grapefruit oil, and mixtures thereof;- other essential oils and essential oil mixtures known from the prior art.Oils - triglycerides and triglyceride mixtures- preferably walnut oil, grape seed oil, fractionated coconut oil, apricot kernel oil, rosehip seed oil and argan oil;- other triglycerides and triglyceride mixtures known from the prior art.Oil -soluble substances and active agents- preferably propolis (propolis extract ) ;- preferably vitamin E ( tocopherol ) ;- preferably Acmella extract ;- other oil-soluble substances and active agents known from the prior art .Substances addable to the nanoemulsion in a fourth step for producing a nanoemulsion end-use product- preferably preservatives , such as phenoxyethanol ;- preferably water-soluble substances and active agents , particularly vitamin F;- preferably alcohols , particularly ethanol and glycerine ;- preferably acids and bases ;- preferably gelling agents , particularly xanthan gum and carbomer ;- other ingredients known from the prior art , depending on the intended field of use .3 . The process according to claim 1 , wherein the concentration of the nanoemulsion can be adj usted, depending on the intended application, either during formulation or by subsequent dilution of the prepared nanoemulsion in an arbitrary manner .4 . The process according to claim 1 , wherein, for preparing the nanoemulsion, no monohydric or polyhydric alcohol of any carbon chain length is employed as an emulsi fier and / or coemulsi fier or as a formulation aid .5 . The process according to claim 1 , wherein no high-speed homogeniser, high-pressure homogeniser or ultrasonic device is employed during the homogenisation .

6. The process according to claim 1, wherein all process steps are carried out at ambient temperature and at atmospheric pressure .

7. The process according to claim 1, wherein the droplet size of the nanoemulsion is maintained upon scale-up, that is, during the production of larger quantities of the nanoemulsion .

8. The process according to any one of claims 1 to 7, wherein the fields of use and forms of the products produced during the process are as follows:- the premix produced in step 2 is usable as a plant protection agent when the premix is manually mixed with tap water, thereby producing a nanoemulsion that remains stable for several days;- the nanoemulsion produced in step 3 is applicable in fields of use known from the state of the art;- the nanoemulsion end-use product produced in step 4 is usable in the form of liquids and / or sprays as cosmetic products, plant care products, insect repellents, beverages and medicinal preparations, and, in gelled form, as gels, soft gelatin capsules, cosmetic products and medicinal preparations .

9. The process according to claims 1 to 8, wherein the emulsifiers and / or co-emulsif iers used in the first step of the process are selected from the following: polysorbate 80 (polyoxyethylene [ 20 ] sorbitan monooleate, Tween 80) , referred to as T80, and polysorbate 20 (polyoxyethylene [ 20 ] sorbitan monolaurate, Tween 20) , referred to as T20.

10. The process according to claims 1 to 9, wherein the ratio of T80 to T20 is selected according to the followinggroupings and values :- in the case of triglycerides, exclusively T80 may be used, or preferably the ratio of T80 to T20 is at least 1 / 1;- in the case of essential oils, the T80 / T20 ratio is preferably less than or equal to 1 / 1, more preferably from 1 / 7 to 1 / 1, and particularly preferably from 2 / 5 to 1 / 1.

11. The process according to any one of claims 1 to 10, wherein the ratio of the T80 emulsifier to the oil used in the first step of the process has a preferred minimum value, below which, irrespective of the amount of T20 added, a clear and transparent nanoemulsion is not formed at a later stage .

12. The process according to any one of claims 1 to 11, wherein the adjustment of the emulsif ier-to-oil (E / O) ratio is carried out based on knowledge of the relationship between droplet size and the amount of emulsifier required to achieve the droplet size, taking into account that the required E / O ratio is inversely proportional to the droplet size .

13. The process according to claim 12, wherein the E / O ratio is from 3 to 8, preferably about four, which corresponds to a nanoemulsion having a droplet size below 30 nm, which, in the case of colourless oil, results in a clear, water-like transparent nanoemulsion and, in other cases, a transparent nanoemulsion .

14. The process according to any one of claims 1 to 13, wherein the optimal T80 / T20 and E / O ratios depending on the oil and / or oil mixture are set in accordance with the data summarised and illustrated in Tables 5 and 6 and in Diagram 20 (Figure 19) , and in accordance with the desired dropletsi ze , in such a way that the components comprising the emulsi fiers and oils are measured in any order and homogenised, thereby obtaining a homogeneous mixture at ambient temperature within five minutes .15 . The process according to any one of claims 1 to 14 , wherein in the first step of the process preferably a mixture of several oils is used, particularly preferably an essential oil-essential oil mixture , a triglyceridetriglyceride mixture , or an essential oil-triglyceride mixture .16 . The process according to any one of claims 1 to 15 , wherein in the second step of the process , for producing the premix, water is added to the mixture prepared in the first step, and, in order to avoid unmanageable viscosity, a combination of the PIC2 and PIC1 methods ( PIC2 / PIC1 technique ) is applied in such a manner that first a smaller amount of water is added to the organic phase so that the system does not yet reach a bicontinuous composition, and thereafter the process is switched to the other technique and the mixture is dispersed into the aqueous phase according to the PIC1 method, thereby producing emulsions that are more stable than those obtained by applying the PIC1 method alone .17 . The process according to any one of claims 1 to 16 , wherein during the second step the amount of water added depends on the factors listed below and the addition of water is carried out as described below :- for producing a more stable nanoemulsion, i f exclusively the T80 emulsi fier is used or i f the T80 / T20 ratio is greater than 1 , preferably an amount of water corresponding to hal f of the mass of the oil is suf ficient , or a largeramount may be added, in which case the viscosity increases ;- for producing a more stable nanoemulsion, i f the T80 / T20 ratio is less than or equal to 1 , preferably an amount of water corresponding to the sum of the masses of the oil and T20 is added;- this amount is close to the bicontinuous composition, and the viscosity of the mixture does not increase excessively due to the higher T20 concentration, meaning that the smaller the T80 / T20 ratio , the more water can be added without forming a paste-like gel ; the amount of water to be added is not limited to these two relationships , these being heuristics intended to approach the bicontinuous composition as closely as possible ;- the water is added either in a single portion or slowly, the latter increasing the preparation time ;- the resulting mixtures are mixed without excessive intensity until homogeneous , avoiding the presence of gel fragments , which, i f the mixer provides adequate mixing, takes 5-10 minutes ;- the premix obtained as a result of the second step of the process is usable on its own as a plant protection concentrate , from which, for use , the nanoemulsion is prepared by aqueous dilution to the required concentration, preferably using tap water, as supported by the results of T1PRE and E1PRE as well as T1PRE* and E1PRE* shown in Graphs 12-15 ( Figures 14-15 ) .18 . The process according to any one of claims 1 to 17 , wherein in the third step of the process the premix prepared in the second step is added to the aqueous phase and / or water in the manner described below :- a desired amount of water is measured to prepare a nanoemulsion of appropriate concentration, and the premix is added to the water in a thin but steady stream undercontinuous intensive mixing, this process taking approximately 1-2 minutes ;- intensive mixing is required during and after the addition, but the use of a high-speed, high-shear homogeniser is not necessary;- the premix may also be added more slowly to the water, which increases the production time , and the use of a homogeniser is possible but not a prerequisite of the process ;- after the addition, the mixture is mixed for at least one hour, as a shorter time negatively af fects the stability of the nanoemulsion;- for comparability, the nanoemulsion samples described were mixed for one hour ;- during mixing, the mixer and its position are selected so as to avoid introducing air into the system, as this would result in intensive foam formation;- the results are summarised in Graphs 1-19 ( Figures 9-17 ) .19 . The process according to any one of claims 1 to 18 , wherein the premix used in the third step is prepared by pre-mixing several oils and is then added to the water .20 . The process according to any one of claims 1 to 19 , wherein the premix used in the third step is prepared separately for each oil , and one premix is added to the water to produce an intermediate nanoemulsion, after which the premix prepared from the other oil is added to the resulting intermediate nanoemulsion to obtain the final nanoemulsion .21 . The process according to any one of claims 1 to 20 , wherein during the process , for producing cosmetic nanoemulsion end-use products , preferably skin care , woundtreatment and hair care products, the apolar base materials and oils applicable during the preparation of the nanoemulsion may be selected from the following, without limiting the scope of protection thereto:- any oil used in the cosmetic industry, preferably containing a high amount of triglycerides (generally referred to as triglycerides) , particularly preferably walnut oil, grape seed oil, argan oil, coconut oil, olive oil and rosehip seed oil;- any essential oil used in the cosmetic industry, meaning any fragrance-containing, water-insoluble oil, particularly preferably lavender oil, lemon oil, jasmine oil and rose oil ;- apolar substances or cosmetic base materials having similar physical properties, particularly preferably vitamin E, coenzyme Q10 and plant extracts, particularly preferably Acmella extract.

22. The process according to any one of claims 1 to 21, wherein in the fourth step of the process, for producing cosmetic nanoemulsion end-use products, preferably skin care, wound treatment and hair care products, the following base materials may be added to and used with the nanoemulsion produced in the third step, without limiting the scope of protection thereto:- aqueous-based excipients and / or active agents that are water-soluble, water-miscible or capable of interacting with water;- depending on the desired form of appearance and rheological and other properties, any cosmetic active agents and excipients, preferably gelling agents, preservatives, vitamins, and monohydric or polyhydric alcohols of any carbon chain length, preferably glycerine, ethanol, isopropanol and benzyl alcohol.

23. The process according to any one of claims 1 to 22, wherein during the process, for producing food-industry nanoemulsion end-use products, applicable base materials may be selected from the following, without limiting the scope of protection thereto:- food-industry hydrophobic nutrients, end products or excipients, preferably flavourings, lipids, preservatives and vitamins;- apolar base materials, preferably oil-soluble foodindustry active agents, particularly preferably vitamins A, D and E, carotenoids, lycopene, lutein, curcumin, resveratrol and CBD.

24. The process according to any one of claims 1 to 23, wherein essential oils, preferably pine oil, may function on their own as carrier oils, thereby enabling synergistic effects with synthetic agents soluble therein.

25. The process according to any one of claims 1 to 24, wherein the triglyceride and essential oil nanoemulsion premix prepared in step 2 is usable on its own as a plant protection concentrate, from which, prior to use, the nanoemulsion is prepared by aqueous dilution to the required concentration, preferably by manual mixing or by means of mixers of field sprayers, optionally using tap water, whereby the nanoemulsion can thus be applied as a plant protection agent due to its simple, on-site preparation.

26. The process according to claims 1 to 25, wherein the nanoemulsion prepared in this manner preferably has a droplet size of less than 30 nm and remains stable for several days.

27. The process according to claims 1 to 26, wherein the nanoemulsions prepared in this manner have a droplet size of 11-19 nm and, upon scale-up to a prepared solution volume of 10 litres, have a droplet size of less than 25 nm.

28. The process according to any one of claims 1 to 27, wherein for producing medicinal and pharmaceutical nanoemulsion end-use products, the apolar base materials required may be selected from the following, without limiting the scope of protection thereto: semi-synthetic oily esters, triglycerides, partial glycerides, and, as further base materials, non-ionic ester emulsifiers.

29. The process according to claims 1 to 28, wherein in nanoemulsion medicinal and pharmaceutical preparations the following are used as carrier oils, without limiting the scope of protection thereto: coconut oil, sesame oil, cottonseed oil, vitamin E (D-tocopherol ) , and, for parenteral and oral administration, oleic acid, ethyl oleate, synthetic lipids, preferably Caproyl 90, triacetin, isopropyl myristate, oleic acid, palm oil esters, corn oil, olive oil, isopropyl palmitate, Labrafil MM44 CS, Maisine 35-1, Miglyol 812 and Captex 200.

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