EP1811948A1 - Non-aqueous system having viscoelastic properties - Google Patents

Abstract

A non-aqueous system having viscoelastic properties, comprising a surface-active substance, an oil component, and a pyrogenically prepared silica that has been rendered hydrophobic, exhibits viscoelastic properties and is characterised by storage modulus, loss modulus, loss factor and yield point. The non-aqueous system having viscoelastic properties can be used in the preparation of suspensions of active ingredients.

Description

Non-aqueous system having viscoelastic properties

The invention relates to a system having viscoelastic properties, to a process for its preparation, and to its use in the preparation and storage of formulations of herbicides, pesticides and cosmetic and pharmaceutical preparations.

Solid pesticides are commonly formulated as emulsifiable suspension concentrates, wherein typically a pesticidally active ingredient in a solid particulate state is suspended in a non-active liquid carrier. The liquid carrier in such concentrates can be aqueous or non-aqueous, for example a hydrocarbon oil or other organic liquid, and is selected such that the solid pesticide has low solubility in the liquid carrier.

Most_so-lid—pesticides—are—of—1ow—so1-ubi-li-fey—in—water—and- can be formulated as aqueous suspension concentrktes, or as non-aqueous suspension concentrates wherein the liquid carrier is not an effective solvent for the pesticide.

Suspension concentrate formulations preferably have a high concentration of active ingredient, have good storage stability, and are easy to use. In particular, because these concentrates are typically diluted with water at the time of use, they must be readily emulsified in water, and have good emulsion stability in the diluted state.

Physical stability of suspension concentrates, both during storage and during use, is of particular concern with these formulations having a solid particulate phase and a continuous liquid phase. Suspension concentrates are inherently unstable in a gravitational field because of difference in density between the solid pesticide and the liquid carrier, which can result in separation of the formulation over time into a pesticide-rich layer and a carrier-rich layer. In extreme cases, phase separation occurs, wherein the solid particulate pesticide, typically the denser phase, settles at the bottom of the liquid phase. It is therefore generally necessary to include one or more suspension aid(s) in the formulation to assist in maintaining suspension of the solid and thereby improve the physical stability. If separation occurs, it is preferred that the solid can be readily resuspended with minimum agitation of the formulation.

Further, a pesticidal suspension concentrate to be used in the agricultural industry is typically diluted with water to prepare a dilute sprayable composition which is then applied by spraying to soil and/or plants in a field, for example by means of conventional spraying equipment. At the time of use, therefore, it is desirable that the suspension concentrate is readily emulsified in water, with no more than a minimal and acceptable amount of segregation _of components into distinct layers referred to in the industry as "creaming", sedimentation. In order to accomplish this, one or more surfactants or emulsifiers are therefore also typically included in suspension concentrates to improve dispersibility in water.

Suspension concentrates having an oil as the liquid carrier are particularly troublesome and require an emulsifier that is capable, by a process of emulsification, of dispersing the oil without forming gels or lumps, and distributing the pesticide in the aqueous phase of a dilute sprayable composition. This emulsification must take place quickly, without complications.

As conventionally understood, the term, pesticide, is inclusive of insecticides, herbicides, fungicides, and other active ingredients. When the pesticide active ingredient is soluble in, for example, a hydrocarbon fluid, an emulsifiable concentrate solution can be made by combining suitable surfactants with the hydrocarbon fluid and active ingredient. When the active ingredient is not soluble in an organic fluid and not chemically stable in water, an alternative approach is needed.

One approach is to suspend pesticide particles in an organic fluid/surfactant solution. For the particles to remain suspended and not settle to the bottoms of their containers appropriate rheological properties must be achieved in the final suspension. This could be achieved with viscous hydrocarbon oils; however, most viscous hydrocarbon oils are phytotoxic. Consequently, one would prefer to use lower viscosity organic fluids that are not phytotoxic and to then thicken or viscosify the fluids to a suitable viscosity with a thickening agent. Common thickening agents for organic fluids that could be used include soluble polymers and network or structure forming compounds such as fumed silicas, clays, and materials that are crystalline or., semi-crystalline in the fluidl at application temperature, but soluble in the fluid at an elevated temperature.

While all these agents can thicken organic fluids, many are not compatible with the surfactants needed to disperse the concentrate in water. For example, a small concentration (about 5 wt.%) of a high molecular weight (about 2 million) polyisobutylene can thicken a mixed aliphatic hydrocarbon. When a blend of surfactants that is soluble in the aliphatic hydrocarbon and capable of dispersing it in water is added, the complete mixture does not form a solution, but instead separates into two phases.

According to US 6,464,996 Exxon Mobil Chemical Patents Inc. a similar amount of a hydrophobic fumed silica can also thicken a mixed aliphatic hydrocarbon; however, when the same dispersing surfactant blend is added, the viscosity of the solution drops back close to the level of the neat hydrocarbon fluid. Accordingly, it is known from the prior art that non-aqueous systems can be thickened by means of fumed silicas. This is also true, for example, of plant protection formulations (US 5,397,773, WO 02/21921). It is likewise known from the prior art that, in a disadvantageous manner, the viscosity of such suspensions thickened by means of fumed silica is markedly reduced by the addition of a surface-active substance and assumes almost the value of the unthickened oil (US 6,464,996).

The viscosity of thickened suspensions/emulsions/ suspoemulsions by the use of silicas, described by the measured viscosity of these systems, is used as a means of evaluating the settling properties of such systems. According to the prior art, the shear viscosity, determined by means of rotational measurement, has always been used as a measure of the thickening.

However, rotational measurement of the shear viscosity destroys ^"the^{" "}siTicaTsurfac^'ta^'nt network during^"the^"" measurement itself and is therefore not suitable for describing the structures at rest, which are critical for the settling behaviour. Many highly viscous fluids do not have a yield point, for example, and as a result cannot prevent settling in the long term.

In contrast, by the use of highly sensitive oscillation rheometers, the viscoelastic properties of silica structures are measured in the so-called linear viscoelastic range and accordingly describe the gel structure that actually exists in the state of rest.

A suspension is stable in the long term when the structural strength of a spatial network formed in the fluid is greater in the state of rest than the weight of the particles to be stabilised in the suspension. The yield point describes this structural strength in the state of rest. The relationship between the yield point and the particle size that can be stabilised can be described as follows:

τ = F where F = V_Sphere-Ap -g A

τ = V_sp_here-Δp -g => τ = g^•Ap -r

•"•sphere -J wherein: τ = yield point (Pa)

Δp = difference in density between fluid and active ingredient particles (kg/m³ ) r = radius of active ingredient particles d₉₅ value (m) g = acceleration due to gravity 9.81 m/s²

V_sp_here = volume of a sphere having the radius of the active ingredient particles dg₅ value (m)

•^-_sph_er_e = surface area of a sphere having the radius of the active ingredient particles dg₅ value (m)

Accordingly, the object was to invent non-aqueous systems that are thickened with fumed silicas in such a manner that particles suspended therein are prevented from settling out in the long term. The addition of surface-active substances should not - as described in US 6,464,996 - damage the structural strength that has been built up. The yield point and not the shear viscosity is to be used as a measure of the long-term stability of the suspension.

The invention provides a non-aqueous system having viscoelastic properties, which system is characterised in that it comprises a surface-active substance or a mixture of surface-active substances, an oil component and a pyrogenically prepared silica. The non-aqueous system according to the invention can exhibit viscoelastic properties characterised by storage modulus, loss modulus, loss factor and yield point.

In a preferred embodiment of the invention, the non-aqueous system is characterised in that the surface-active substance is non-ionic.

In the non-aqueous system according to the invention, the viscoelastic properties can be enhanced by the cooperation of surface-active substances and pyrogenically prepared silicas.

According to the invention, suspensions/emulsions/ suspoemulsions comprising at least one non-aqueous medium, a surface-active substance and an active ingredient that is insoluble in the fluid have been stabilised using silicas. The viscoelastic properties, in particular the yield point, of these systems have been determined by means of a newly developed measuring method. The measuring results -allow- better prediction of the expected stability of suspensions/ emulsions/suspoemulsions. It is thus possible to adjust viscoelastic properties in a specific manner for the purpose of stabilising a suspension.

It has been found, surprisingly, that the yield point of non-aqueous suspensions/emulsions/suspoemulsions stabilised with silica is dependent in a significant manner on the nature of the surface-active substance that is used. Again surprisingly, an opposite effect was found, as described in US 6,464,996. In contrast to a liquid system that does not comprise a surface-active substance and in which no structure at all was to be recognised, the yield point could be adjusted in a specific manner by the use of different surface-active substances.

In principle there can be used anionic, cationic, non-ionic and amphoteric surfactants, including polymeric surfactants and surfactants having heteroatoms in the hydrophobic group, as well as mixtures of the groups of surfactants.

The anionic surfactant can correspond to the formula R⁵-SO₃ ^~ 1/n M⁽ⁿ⁺⁾ (III), wherein M is a mono- or di-valent cation (n = 1 or 2) and R⁵ represents a straight-chain or branched, aliphatic or heteroaliphatic radical having from 6 to 30 carbon atoms or a (Ce-Cso-alkyl)aryl radical.

The non-ionic surfactant can correspond to the formula [R⁶-CO- (E0)_x ^"]_yA² (IV), wherein R⁶ represents a straight- chain or branched, saturated or unsaturated, optionally mono- or di-hydroxylated aliphatic radical having from 8 to 30 carbon atoms, the sum of all x is from zero to 100, y represents 1, or A² is derived from a C₃-C₇-polyol when y represents from 2 to 7.

The anionic surfactants include, for example, carboxylates, especially alkali, alkaline earth and ammonium salts of -£atty--acids-,—.e-..g-..-potassium stearate., which-are usually- also referred to as soaps; acyl glutamates; sarcosinates, e.g. sodium lauroyl sarcosinate; taurates; methyl celluloses; alkyl phosphates, especially mono- and di- phosphoric acid alkyl esters; sulfates, especially alkyl sulfates and alkyl ether sulfates, such as, for example, sodium dodecyl sulfate (SDS) C₂H₂₅So₄Na, sodium dodecylbenzenesulfonate Ci₂H_2SCeH₅-SO₃Na; sulfonates, especially sulfonates of formula (III) , further alkyl- and alkylaryl-sulfonates, especially alkali, alkaline earth and ammonium salts of arylsulfonic acids as well as alkyl- substituted arylsulfonic acids, alkylbenzenesulfonic acids, such as, for example, ligno- and phenol-sulfonic acid, naphthalene- and dibutylnaphthalene-sulfonic acids, or dodecylbenzenesulfonates, alkyl naphthalenesulfonates, alkylmethyl ester sulfonates, condensation products of sulfonated naphthalene and derivatives thereof with formaldehyde, condensation products of naphthalenesulfonic acids, phenolic and/or phenolsulfonic acids with formaldehyde or with formaldehyde and urea, mono- or di- alkylsuccinic acid ester sulfonates; as well as albumin hydrolysates and lignin sulfite waste lyes. The above- mentioned sulfonic acids are advantageously used in the 5 form of their neutral or optionally basic salts.

The cationic surfactants include, for example, quaternised ammonium compounds, especially alkyltrimethylammonium and dialkyldimethylammonium halides such as, for example,

cetyltrimethylammonium chloride C16H33 (CH₃) 3NCI 10 Ci₂H₂₅

\ didodecyl dimethylammonium chloride / N(CHs)₂-Cl

C12H25

and alkyl sulfates as well as pyridine and imidazoline derivatives, especially alkylpyridinium halides.

-1-5 -The—non—i-oni-e- su-rfae-t-an-ts- i-neiude, -for-example-,- the • - compounds of formula (IV) , further alkoxylates alnd, especially, ethoxylates, as well as non-ionic surfactants, especially

non-ionic surfactants like

20 large hydrophilic head group (based on ethylene oxide) dodecyl hexaethylene glycol monoether Ci₂H₂₅(CH₂-CH₂-O)₆-OH abbreviated Ci₂E₆ nonyl phenol ethoxylates C₉Hi₉-C₆H₅- (CH₂-CH₂-O) ₉OH;C₉φE₉

small hydrophilic head group

25 CH₃

dodecyl dimethylamine oxide Cl₂H₂₅-N-K)

CH₃

dedecyl sulphicyl ethanol Ci₂H₂₅-SO-CH₂-OH - fatty alcohol polyoxyethylene esters, for example lauryl alcohol polyoxyethylene ether acetate,

- alkyl-polyoxyethylene and -polyoxypropylene ethers, e.g. of iso-tridecyl alcohol and fatty alcohol polyoxyethylene ethers, alkylaryl alcohol polyoxyethylene ethers, e.g. octylphenol-polyoxyethylene ether,

- alkoxylated animal and/or vegetable fats and/or oils, for example maize oil ethoxylates, castor oil ethoxylates, tallow ethoxylates,

- glycerol esters, such as, for example, glycerol monostearate,

fatty alcohol alkoxylates and oxoalcohol alkoxylates, especially of the type RO- (RgO)_x(RioO)_yRn where R₉ and Rio independently of one another = C₂H_4/ C₃H₆, C₄H₈ and Rn = H, or Ci-Ci2-alkyl, R = C₃-C₃₀-alkyl or C₆-C₃o-alkenyl, x and y independently of one another are from 0 to 50, wherein x and y may not both be 0, such as iso-tridecyl alcohol and oleyl alcohol polyoxyethylene ether,

alkylphenol alkoxylates, such as, for example, ethoxylated isooctyl-, octyl- or nonyl-phenol, tributylphenol-polyoxyethylene ether,

fatty amine alkoxylates, fatty acid amide and fatty acid diethanol amide alkoxylates, especially their ethoxylates,

sugar surfactants, sorbitol esters, such as, for example, sorbitan fatty acid esters (sorbitan monooleate, sorbitan tristearate) , polyoxyethylene sorbitan fatty acid esters, alkyl polyglycosides, N-alkyl gluconamides, alkylmethyl sulfoxides,

- alkyldimethylphosphine oxides, such as, for example, tetradecyldimethylphosphine oxide.

The amphoteric surfactants include, for example, sulfobetaines, carboxybetaines and alkyldimethylamine oxides, e.g. tetradecyldimethylamine oxides or 3-dimethyl dodecyl propane sulfonate (betaines)

Ci₂-H₂₅-N-CH₂-CH₂-CH₂-SO₃ ^{" "}

(CH₃)₂ lecithin, swelling surfactant-a triglyceride Ci₇H₃₅-COO-CH₂

Ci₇H₃₅-COO-CH 0^"

^" CH₂ - 0 - P- 0- CH₂ -CH₂ ¹⁷CH₂ -N ( CH₃ )^" ₃ ^'

0

The polymeric surfactants include, for example, di-, tri- and multi-block polymers of the (AB)_x, ABA and BAB type, e.g. polyethylene oxide block polypropylene oxide block polyethylene oxide, polystyrene block polyethylene oxide, and AB comb polymers, e.g. polymethacrylate comb polyethylene oxide.

Partially hydrolysed poly(vinyl acetate) commonly referred to as poly(vinyl alcohol)

(CH₂-CH)_x- (CH₂-CH)_y(CH₂-CH)_x-

OH OCOCH₃ OH

Polyethylene oxide-polypropylene oxide poly(ethylene oxide) block copolymers commonly referred to as luronics HO- ( CH₂-CH₂-O) _x- (CH₂-CH-O ) _Y- (CH₂-CH₂-O) x-OH

CH₃

Further surfactants which should be mentioned here by way of example are perfluoro surfactants, silicone surfactants, phospholipids, such as, for example, lecithin or chemically modified lecithins, amino acid surfactants, e.g. N-lauroyl glutamate, and surface-active homo- and co-polymers, e.g. polyvinylpyrrolidone, polyacrylic acids in the form of their salts, polyvinyl alcohol, polypropylene oxide, polyethylene oxide, maleic anhydride-isobutene copolymers and vinylpyrrolidone-vinyl acetate copolymers, as well as polyelectrolytes such as, for example,

Naphthalene formaldehyde sulfonated condensates Lignosulfates: anionic polyelectrolytes prepared by sulfonation of wood lignin (complex structures)

Polyacrylic acid and polyacrylic/polymethacrylic acid

CH₃

-

Polyvinylpyridiunium salt

or

polyethers, such as, for example, polyethylene glycols, polypropylene glycols, such as, for example, Pluriol® P types or copolymers thereof, such as, for example, Plunonic® PE types.

Polyvinyl alcohols, e.g. Mowiol® alkyl polyglycosides fatty amine polyglycol ethers fatty amine N-oxides alkylsulfoxides Unless specified, the alkyl chains of the surfactants listed above are linear or branched radicals usually having from 8 to 20 carbon atoms.

The surfactant component can be formed by an anionic surfactant of formula (III) . These are particular sulfonates. They include especially alkanesulfonates as well as sulfosuccinates, so that R⁵ advantageously represents an aliphatic or heteroaliphatic radical that is straight-chain or branched - especially branched one or two times - and has from 6 to 30, preferably at least 8 and especially from 12 to 24 carbon atoms. For alkanesulfonates, R⁵ may be derived especially from fatty alkyl radicals, for example based on the above-mentioned fatty acids. Particular heteroaliphatic radicals are interrupted by one or two ester groupings -OC(O)-. R¹ in this connection represents especially succin-2-ylates, including mono- and di-esters, and α-bonded fatty acid esters.

Sulfosuccinates are preferred anionic surfactants of formula III. R⁵ here represents a radical -CH(C (0) -0-R⁷)CH₂- C(O)-O-R⁸, wherein R⁷, R⁸ independently of one another may have the meanings given for R³ and R⁴ and represent especially alkyl radicals having from 1 to 12 and preferably from 5 to 8 carbon atoms. A preferred alkyl radical is octyl, especially iso-octyl.

Because of the negative charge of anionic surfactants, counter-ions are required, so that M represents a mono- or di-valent cation. In principle, any inorganic or organic cation that can be used in agriculture is suitable. Preference is given to cations of metals, such as lithium, sodium, calcium, potassium, magnesium, zinc, manganese, particular preference being given to lithium, sodium and calcium. A sulfosuccinate is dioctyl succinate, for example the sodium salt.

The anionic surfactants of formula III also include alkylarylsulfonates, so that R⁵ advantageously also represents an alkyl-substituted alkyl radical. The aryl radical may be mono- or poly-substituted, especially di- or tri-substituted, by identical or different alkyl radicals, it being possible for two substituents to occupy the same position. The alkyl radicals generally have from 6 to 30, preferably from 10 to 24 and especially from 8 to 12 carbon atoms. They may, independently of one another, be straight- chain or branched, especially branched 1, 2, 3 or 4 times. Of the straight-chain alkyl radicals there may be mentioned, for example, decanyl, undecanyl, dodecanyl, tridecanyl and tetradecanyl, and of the branched alkyl radicals there may be mentioned, for example, tetrapropylene. A preferred aryl radical is phenyl.

An alkylarylsulfonate may be άodecylpheήylsulfonate, for example the sodium, lithium or calcium salt.

Where present, the amount of anionic surfactants of formula III, based on the total weight of the oil suspension concentrate, is generally from 1 to 40 wt.%, preferably from 7.5 to 30 wt.% and especially from 10 to 30 wt.%.

The surfactant component may further be formed by a non-ionic surfactant of formula IV. These are optionally ethoxylated carboxylic acids and esters of mono- or poly- functional alcohols (polyols) .

The radical R⁶ is derived especially from fatty acid radicals, for example those mentioned above, so that R⁶ advantageously represents an optionally mono- or di- hydroxylated aliphatic radical that is straight-chain or branched - especially branched 1 to 2 times - and saturated or unsaturated - especially mono-, di- or tri-unsaturated - and that has from 8 to 30, preferably from 12 to 24 and especially from 10 to 24 carbon atoms. These include especially palmityl, stearyl, arachidyl, hexadecenyl, oleyl, linoIyI, linolenyl, ricinoleyl, eicosanyl and also mono- and di-hydroxystearyl, of which ricinoleyl and oleyl are preferred.

If the non-ionic surfactants of formula IV are ethoxylated, then the sum of all x gives the mean ethoxylation number, which is generally from 3 to 100 and especially from 5 to 50.

If A² is hydroxy, then y = 1 and the mean ethoxylation number is advantageously from 5 to 50 and preferably from 15 to 40. Special mention is to be made in this connection of corresponding ricinoleic acid and oleic acid polyethoxylates.

~I-f—A—r-ep-r-esen-ts--op-t-iona-l-l-y-branched—a-1-kyl-θx-y-ha-v-i-ng—f-r-em—1- to 4 and preferably 1 or 2 carbon atoms, then y = 1 and the mean ethoxylation number is from 3 to 100 and preferably from 20 to 50.

If A² is derived from a polyol having from 3 to 7 and especially 6 carbon atoms, then the value of y = from 2 to 7 and preferably from 3 to 6. y hydroxy hydrogen atoms of the radical A² are here each replaced by a radical R⁶-CO- (EO)_x-, wherein a plurality of radicals R⁶ and a plurality of indices x may be identical or different. Preferably, a plurality of radicals R⁶ are identical, while the indices x may be different and generally follow a normal distribution. In particular, A² is derived from a sugar alcohol, such as sorbitol or glycerol. A preferred meaning of A² is sorbitol. If ethoxylated, the mean ethoxylation number is from 5 to 50 and preferably from 15 to 40. Special mention is to be made in this connection of the corresponding sorbitol polyethoxy-oleates and -stearates. The surface-active substance or surfactant should contain groups such as, for example, R-OH and/or R-O-R' . These groups are able to interact with the silanol groups of the pyrogenically prepared hydrophilic and or hydrophobic silica. The surface-active substance should be soluble or dispersible in the oil component.

Preferred surfactants according to the invention are fatty alcohol polyglycol ethers, alkylphenol polyglycol ethers, fatty acid polyglycol esters, liquid polyalkoxylated aliphatic alcohols or amines. These are prepared by alkoxylation of fatty alcohols or amines containing from 9 to 24, preferably from 12 to 22, especially from 14 to 20 carbon atoms with alkylene oxides containing from 2 to 6, preferably from 2 to 3 carbon atoms, especially with a mixture of ethylene oxide and propylene oxide. The aliphatic radical of the fatty alcohols or fatty amines may be straight-chain or branched.

These co^~mpbnentεF^~ϊήay correspond^"tcT the formula H_2n+I I_n-Xt(CH₂-CH₂-O)_x(CH₂-CH(CH₃)OyH]₂,

in which X = 0 or N z = l when x = 0 or 2 when x = N n = from 9 to 20 x = from 1 to 8 Y = from 6 to 12.

A suitable surfactant mixture according to the invention may be a combination of alkyl and/or alkylaryl ethoxylates having from 6 to 36 carbon atoms and from 2 to 60 ethylene oxide units (EO) and alkyl- and/or alkylaryl-sulfonates having from 6 to 36 carbon atoms. The former include, for example, surfactants such as those from the ^®Arkopal series (Hoechst AG) , which are nonylphenols having from 3 to 50 EO, or from the ^®Genapol series (Hoechst AG) , which are fatty alcohols such as coconut fatty alcohol, oleyl alcohol, stearyl alcohol, tallow alcohol etc. or isotridecyl alcohol having from 2 to 40 EO . These ethoxylates may additionally be phosphated and optionally neutralised by means of bases such as alkali or amines , such as ^®Emcol 136 (Witco Chem) , which is an alkylphenol polyglycol ether phosphate neutralised with alkali . Suitable alkylarylsulf onates are surfactants such as Ca dodecylbenzenesulf onate (Hoechst AG) .

In a particularly preferred embodiment of the invention, the non-ionic surfactants Pluronic PE 10500 , Pluriol P 4000 and/or Pluriol P 2000 can be used .

Plurionic PE 10500 is a block polymer of the formula :

HO (CH₂CH₂O ) x (CH-CH₂-O) _y (CH₂OH₂O) _ZH

CH₃

Pluriol P 4000 and Pluriol P 2000 are polypropylene glycols of the formula :

HO (CH-CH₂O) _nH

I

CH₃

The oil component may be:

In principle there can be used, for example, mineral oils, synthetic oils and vegetable and animal oils.

These include especially aprotic solvents, such as mineral oil fractions having a moderate to high boiling point, for example kerosene and diesel oil, also coaltar oils, hydrocarbons, paraffin oils, optionally hydrogenated or partially hydrogenated aromatic compounds or alkyl aromatic compounds from the benzene or naphthalene group, aliphatic or aromatic carboxylic acid or dicarboxylic acid esters, especially the esters of formulae (Ha) or (lib) , fats or oils of vegetable or animal origin, such as mono-, di- and tri-glycerides, in pure form or as a mixture, for example in the form of oily extracts of natural substances, for example cottonseed oil, coconut oil, palm oil, thistle oil, olive oil, soybean oil, sunflower oil, castor oil, sesame oil, maize oil, groundnut oil, rapeseed oil, linseed oil, almond oil, castor oil, safflower oil, and refined products thereof, for example hydrogenated or partially hydrogenated products thereof, and/or esters thereof, especially methyl and ethyl esters, such as, for example, soybean oil acid esters, especially soybean oil acid methyl ester and ethyl' ester, rapeseed acid esters, especially rapeseed acid methyl ester and ethyl ester, lauric acid esters, stearic acid esters, palmitic acid esters.

Aliphatic or aromatic hydrocarbons, for example toluene, xylene, n-alkanes, iso-alkanes, cycloalkanes, or mixtures thereof.

to Ehe invention,^" only oiT is used^' as the carrier medium; the special addition of water is not necessary and is even wholly undesirable, because only in this manner is the necessary stability of both physical and chemical nature retained. Suitable oils are preferably non-aromatic organic compounds which are liquid and have a boiling point above 62⁰C, preferably above 100⁰C, at normal pressure.

Examples which may be mentioned include: paraffinic oils, such as BP n-paraffin (BP Chemicals) , fatty oils of vegetable or animal origin, such as rapeseed oil, sunflower oil, cottonseed oil, linseed oil, soybean oil, coconut oil, palm oil, thistle oil and castor oil, mono- or poly-hydric alcohols, such as decanol, stearic, lauryl, palmitic, tallow alcohol, glycols and glycerol and polyglycols. Esters of organic carboxylic acids with mono- or poly- hydric alcohols are particularly preferred. Suitable carboxylic acids are, inter alia, those having from 10 to 36 carbon atoms, for the alcohol moiety those having from 1 to 26 carbon atoms. Rapeseed acid methyl esters and ethyl esters, lauric acid isobutyl esters, stearic acid butyl esters, palmitic acid methyl and 2- (ethyl)hexyl esters are particularly suitable. When choosing the appropriate oils, a portion of the active ingredient(s) used may also be in dissolved form in addition to the solid-dispersed phase. However, this is not essential.

The solvent is suitably a water immiscible solvent in which the solubility of the crop protection compound is less than 5 g/1. Preferably, it is an apolar organic solvent selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons, alkyl lactates, glycols and plant oil esters or mixtures thereof. Preferred aromatic hydrocarbons are e.g. toulene, xylenes, or substituted naphtalenes as for example Solvesso^® 200 (Deutsche Exxon Chemicals) or Shellsol^® (Deutsche Shell AG) , preferred aliphatic hydrocarbons are e.g. cyclohexane, paraffins as for example Isopar^® H (Deutsche Exxon Chemicals) or Shellsol^® T (Deutsche Shell AG) , preferred plant oil esters are methylated coconut or soybean oil esters, in particular methyl caprylate such as Witconol 1095 (Witco Corp.), preferred alkyl lactates are ethyl and 2-ethylhexyl lactate, preferred glycols are dialkyl diethyleneglycols, in particular diethyl diethyleneglycol. Mixtures of different solvents are often suitable.

In a particularly preferred embodiment of the invention, soybean oil acid methyl ester can be used.

The term "fumed silicas" is understood to mean highly dispersed silicas which are obtained at high temperatures by coagulation from the gas phase, especially by flame or high-temperature hydrolysis.

In that process, a homogeneous mixture of a vaporisable silicon compound, hydrogen and air is burnt in a flame (Ullmann's Enzyklopadie der technischen Chemie, 4th Edition, Volume 21, page 464 (1982) .

The pyrogenically prepared silica can be rendered hydrophobic using silanes, such as, for example, dimethyldichlorosilane, which react with the silanol groups at the surface of the silica (see Ullmann's Enzyklopadie der technischen Chemie, 4th Edition, Volume 21, page 466 (1982) .

The following silicas, for example, can be used as pyrogenically prepared silicas:

Aerosil 130, Aerosil 130 V, Aerosil 150, Aerosil 150 V, Aerosil 200, Aerosil 200 V, Aerosil 300, Aerosil 380, Aerosil 380 V, Aerosil 90, Aerosil COK 84, Aerosil MOX 170, Aerosil OX 50, Aerosil R 104, Aerosil R 106, Aerosil R 202, Aerosil R 812, Aerosil R 812 S, Aerosil R 8200, Aerosil R 972, Aerosil R 972 V, Aerosil R 974, Aerαs±l_R_9-7_4 -V

In a preferred embodiment of the invention, the pyrogenically prepared silicas Aerosil^® R974, R972 and Aerosil 200 can be used.

The pyrogenic, hydrophobic silica should be present in an amount of at least 0.1; 0.5; 1.00 or 2.00 g/100 g of suspension, in order to ensure the formation of a network structure.

The maximum amount may be 10; 20; 30 g/100 g.

The non-aqueous system according to the invention with its viscoelastic properties can be used in the preparation of emulsions or suspensions of active substances.

By means of the system according to the invention, solids, especially active ingredients such as, for example, pesticides, herbicides, insecticides or fungicides, as well as pharmaceutical and cosmetic active ingredients , can be maintained in a stable suspension .

1

Pesticidal active ingredients may be, for example: Water-insoluble herbicides that can optionally be included in a contemplated composition are exemplified without restriction by aclonifen, amidosulfuron, anilofos, azafenidin, azimsulfuron, benfluralin, benfuresate, bensulfuron-methyl, bensulide, benzofenap, bifenox, bromobutide, bromofenoxim, butamifos, butralin, butroxydim, butylate, cafenstrole, carbetamide, carfentrazone-ethyl, chlomethoxyfen, chlorbromuron, chloridazon, chlorimuron- ethyl, chlornitrofen, chlorotoluron, chlorpropham, chlorsulfuron, chlorthaldimethyl, chlorthiamid, cinmethylin, cinosulfuron, clethodim, clodinafop-propargyl, clomazone, clomeprop, cloransulam-methyl, cycloate, cyclosulfamuron, cycloxydim, cyhalofop-butyl, daimuron, desmedipham, dichlobenil, diclofop-methyl, diflufenican, dimefuron, dimepiperate, dinitramine, dinoterb, diphenamid, dithiopyr, diuron, EPTC, esprocarb, ethalfluraliϊi, ethametsulfuronmethyl, ethofumesate, ethoxysulfuron, etobenzanid, fenoxaprop-ethyl, fenuron, flamprop-methyl, flazasulfuron, fluazifop-butyl, fluchloralin, flumetsulam, flumicloracpentyl, flumioxazin, fluometuron, fluorochloridone, fluoroglycofen-ethyl, flupoxam, flurenol, fluridone, fluroxypyr-1-methylheptyl, flurtamone, fluthiacet-methyl, fomesafen, halosulfuron, haloxyfop- methyl, hexazinone, imazosulfuron, indanofan, isoproturon, isouron, isoxaben, isoxaflutole, isoxapyrifop, lactofen, lenacil, linuron, mefenacet, metamitron, methabenzthiazuron, methyldymron, metobenzuron, metobromuron, metosulam, metoxuron, metribuzin, metsulfuron, molinate, monolinuron, naproanilide, napropamide, naptalam, neburon, nicosulfuron, norflurazon, orbencarb, oryzalin, oxadiargyl, oxadiazon, oxasulfuron, oxyfluorfen, pebulate, pendimethalin, pentanochlor, pentoxazone, phenmedipham, piperophos, primisulfuron, prodiamine, propanil, propaquizafop, propham, propyzamide, prosulfocarb, prosulfuron, pyraflufen-ethyl, pyrazolynate, pyrazosulfuron-ethyl, pyrazoxyfen, pyributicarb,' pyridate, pyriminobac-methyl, quinclorac, quininerac, quizalofopethyl, rimsulfuron, sethoxydim, siduron, sulcotrione, sulfentrazone, sulfometuron, sulfosulfuron, tebutam, tebuthiuron, terbacil, thiazopyr, thifensulfuron, thiobencarb_,, tiocarbazil, tralkoxydim, triallate, triasulfuron, tribenuron, trifluralin, triflusulfuron and vernolate.

Further herbicides can be:

2, 4-D; 2,4-DB; Acetochlor; Acifluorfen; Alachlor;

Alloxidim; Ametryn; Aminotriazole; Asulam; Atrazine; Benazolin; Bensulforon; Bentazone; Bilanafos; Bispyribac- sodium; Bromacil; Bromoxynil; Butachlor; Carfentrazone;

Chlorimuron; Chlorthal; Cinidon-ethyl; Clefoxydim;

Clodinafop; Clopyralid; Cloransulam-methyl; Cumy|luron;

Cyanazine; Desmetryn; Dicamba; Dichlorprop; Diclofop; Diclosulam; Difenzoquat; Diflufenzopyr; Demethachlor;

Dimethenamid; Diquat; Endothal; Ethametsulfuron; Ethoxyfen;

Fenoxaprop; Fluazifop; Flufenacet; Fluoroglycofen;

Flupyrsulfuron; Flurochloridone; Fluroxypyrp; Glufosinate;

Glyphosate; Haloxyfop; Imazamethabenz; Imazamox; Imazapic; Imazapyr; Imazaquin; Imazethapyr; Imazosulfuron; MCPA;

MCPA-thioethyl, MCPB; Mecoprop; Metazachlor;

Methabenzthiazuron; Methyl arsonic acid; Metalachlor;

Oxasulfuron; Paraquat; Picloram; Pretilachlor; Prometryn;

Propachlor; Propazine; Pyrazolinate; Pyrazosulfuron; Pyribenzoxim; Pyrithiobac; Quinoclamine; Quizalofop;

Quizalofop-P-tefuryl; Sulfosate; Sulfosulfuron; Terbumeton;

Terbuthylazine; Terbutryn; Thenylchlor; Triclopyr;

Amicarbazone-BAYMKH3586; Azafenidin-DPX-R6447;

Beflubutamid-UBH-820; Benzfendizone-FMC 143686; Benzobicyclon-SB-500; Butafenacil-CGA 276854; Fentrazamide- BAYYRC2388; Florasulam-DE570; Fluazolate-JV485; Flucarbazone-BAYMKH6562; Flufebpγr-ethyl-S3453 ; Foramsulfuron-AEF 130360; Indanofan-MK-243 ; Iodosulfuron- AEF 115008; Isoxadifen-AEF122006; KPP421; Mesosulfuron - AEF 130060; Mesotrione-ZA1296; MTB-951; OK-9701;

Oxaziclomefone-MY-00; Penoxsulam-DE638; Pethoxamid-TKC-94; Picolinofen-AC900001; Propoxycarbazone (proposed) BAYMKH6561; Pyriftalid-CGA279233; Tepraloxydim- BAS62OH/NP6IEC; Triaziflam-IDH 1105; Trifloxysulfuron (Na salt) - CGA362622; Tritosulfuron

Examples of suitable further pesticides include, but are not limited to, triazines like atrazine, simazine and propazine; sulfonylureas like nicosulfuron, tribenuron, and primisulfuron; carbamates like carbaryl and propoxur, imidazolinones like imazaquin and imazapyr; glyphosate and its carous salts; benzimidazoles like benomyl and thiabendazole; chlorothalonil; biologicals like various bacilli (Bacillus thuringiensis, Bacillus sphaericus) and spiosads; and strobilogens like azoxystrobin.

Further pesticides can be used as:

Insecticide

Abamectin; Acephate; Acequinocyl; Acetamiprid; Acrinathrin;

Alanycarb; Aldicarb; Alpha-cypermethrin; Amitraz; Azinphos- methyl; Azocyclotin; Bacillus thuringiensis; Bendiocarb;

Benfuracarb; Bensultap; Benzoximate; Bifenazate; Bifentrin;

BPMC (Fenobucarb) ; Bromopropylate; Buprofezin; Cadusafos;

Carbaryl; Carbofuran; Carbosulfan; Cartap; Chinomathionat;

Chlorethoxyfos; Chlorfenapyr; Chlorfenvinphos; Chlorfluazuron; Chlormephos; Chloropirifos; Clofentezine;

Cycloprothirin; Cyfluthrin; Cyhexatin; Cypermethrin;

Cyromazine; Deltamethin; Demeton-s-methyl; Diafenthiuron;

Diazinon; Dichlorvos; Dicofol; Dicrotophos; Diflubenzuron;

Dimethoate; Disolfoton; Emamectin benzoate; Endosulfan; Esfenvalerate; Ethiofencarb; Ethion; Ethoprophos;

Etofenprox; Etoxazole; Etrimfos; Fenamiphos; Fenazaquin;

Fenbutatin oxide; Fenitrothion; Fenothiocarb; Fenoxycarb;

Fenpropthrin; Fenpyroximate; Fenthion; Fenvalerate; Fipronil; Flubroythirinate; Flucycloxuron; Flueythrinate;

Flufenoxuron; Flutenzine; Fluvalinate; Formetanate;

Formothion; Fosthiazate; Furathiocarb; Halfenbrox;

Halofenozide; Hexaflumuron; Hexythiazox; Imidacloprid;

Indaxacarb; Isofenphos; Isoprocarb; Isoxathion; Lambda- cyhalothrin; Lindane (Gainma-HCH) ; Lufenuron; Malathion;

Metaldehyde; Methamidophos; Methidathion; Methiocarb;

Methomyl; Methoprene; Methoxyfenozide; Mevinphos;

Milbemectin; Monocrotophos; Nitenpyram; Novaluron;

Omethoate; Oxamyl;. Oxydemeton-methyl; Parathion; Parathion- methyl; Permethrin; Phenthoate; Phorate; Phosalone;

Phosmet; Phosphamidon; Phoxim; Pirimicarb; Pirimiphos- ethyl; Pirimiphos-methyl; Profenofos; Propaphos;

Propargite; Propoxur; Prothiofos; Pymetrozine; Pyraclofos;

Pyridaben; Pyridafenthion; Pyrimidifen; Pyriproxyfen; Quinakphos; Silafluofen; Spinosad; Sulprofos; T^bufenozide;

Tebufenpyrad; Tebupirimfos; Teflubenzuron; Tefluthrin;

Terbufos; Thiamethoxam; Thiocyclam; Thiodicarb; Thiometon;

Tralomethrin; Triazamate; Triazophos; Trichlorfon;

Triflumuron; Vamidothion; Xylyl Methylcarbamate; Zeta- Cypermethrin; Acetoprole-RPA115782; AKD 1022;

Chromafenozide-ANS-118; Clothianidin-TI-435; Dinitefuran-

MTI-446; Ethiprole-RPA 107382; Fluacypyrim-NA-83;

Flupyrazofos; Phosphocarb-BAS301; Protrifenbute-FMC 111869;

Thiacloprid-BAYYRC2894; ToIfenpyrad-OMI-88

Fungicide

Acibenzolar; Azoxystrobin; Benalaxyl; Benomyl; Bitertanol; Bromuconazole; Bupirimate; Captan; Carbendazim; Carboxin; Carpropamid; Chlorothalonil; Chlozolinate; Copper Fungicides; Cymoxanil; Cyproconazole; Cyprodinil; Dichlofluanid; Diclomezine; Diethofencarb; Difenoconazole;

Dimethirimol; Dimethomorp; Diniconazole; Dinocap;

Dithianon; Dodemorph; Dodine; Edifenphos; Epoxiconazole;

Ethaboxam; Ethirimol; Etridiazole; Famoxadone; Fenarimol; Fenbuconazole; Fenhexamid; Fenitropan; Fenpiclonil;

Fenpropidin; Fenpropimorph; Fentin; Ferimzone; Fluazinam;

Fludioxonil; Fluoroimide; Fluquinconazole; Flusulfamide;

Flutolanil; Flutriafol; Folpet; Fosetyl; Fuberidazole;

Furalaxyl; Furametpyr; Guazatine; Hexaconazole; Hymexazol; Imazalil; Imibenconazole; Iminoctadine; Ipconazole;

Iprobenfos; Iprodione/ Iprovalicarb; Isoprothiolane;

Kasugamycin; Kresoxim-methyl; Mancozeb; Maneb; Mepanipyrim;

Mepronil; Metalaxyl; Metconazole; Methasulfocarb; Metiram;

Myclobutanil; Nitrothal-isopropyl; Nuarimol; Oxadixyl; Oxine-copper; Oxolinic acid; Oxycarboxin; Pefurazoate;

Penconazole; Pencycuron; Phthalide; Probenazole;

Prochloraz; Procyinidone; Propamocarb; Propiconazole;

Propineb; Pyrazophos; Pyrifenox; Pyrimethanil; Pyroquilon;

Quinoxyfen; Quintozene; Spiroxamine; Streptomycin; Sulfur; Tebuconazole; Tecloftalam; Tetraconazole; Thiabendazole;

Thifluzamide; Thiophanate-methyl; Thiram; Tolclofos-methyl;

Tolylfluanid; Triadimefon; Triadimenol; Tricyclazole;

Triforine; Tritiforine; Triticonazole; Validamycin;

Vinclozolin; Zineb; Ziram; Cynamidazosulfamid-IKF-916; Cyamidazosulfamid-IKF-916; Diclocymet-S2900; Fenamidone-

RPA407213; Fenoxanil-AC382042/NNF9425; Iprovalicarb-SZX722;

MA 565; Metominostrobin-SSF-126; MTF-753; NF-149; NNF-9850;

Oxproconazole fumarate-UBF-910; Picoxystronin-ZA1963;

Silthiopharm-MON-65500; Simeconazole-Fl55; Trifloxystrobin- OGA279202; Zoxamide-RH7281

PGR

Aminoethoxyvinyl glycine; Prohydrojasmon-PDJ

Nematicide ZA3274 Other

Chlormequat,- Chloropicrin; Choline Chloride; Cyclanilide; Dazomet; Dichlopropene; Dikegulac; Dimethipin; Ethepon; Flumetralin; Gibberellic Acid; Inabenfide; Maleic hydrazide; Mepiquat; Metam; Methyl Bromide; Methyl isothiocyanate; Paclobutrazol; Prohexadione; Thidiazuron; Triapenthenol; Tributyl phosphorotrithioate; Trinexapac- ethyl; Uniconazole; Fluthiacet-KIH9201 / CGA 248757

This list is not meant to be exhaustive but to be representative of the types of pesticides that may be utilized herein.

The invention also provides cosmetic and/or pharmaceutical preparations consisting of a surface-active substance or a mixture of surface-active substances, an oil component, a hydrophilic and/or hydrophobic pyrogenically prepared silica as well as one or more cosmetically or pharmaceutically relevant auxiliary substances and/or active ingredients.

The oils according to the invention can preferably be selected from the group of the polar oils, for example the group of the triglycerides or lecithins. It may be particularly advantageous to use polar oils of vegetable origin, for example avocado oil, cottonseed oil, groundnut oil, thistle oil, jojoba oil, marrow oil, kukui nut oil, macadamia nut oil, maize oil, almond oil, evening primrose oil, olive oil, palm oil, rapeseed oil, sesame oil, soybean oil, sunflower oil, wheatgerm oil, castor oil, safflower oil, grapeseed oil.

It is also possible to use paraffin oil or linear and/or cyclic silicone oils. Suitable synthetic oils may be, for example, - mono-, di-, tri-esters of linear or branched and/or saturated or unsaturated alcohols and fatty acids each having from 6 to 40 carbon atoms;

ethers between linear or branched and/or saturated or unsaturated alcohols each having from 6 to 40 carbon atoms;

- linear and cyclic hydrocarbons having from 6 to 40 carbon atoms.

There may be suitable especially octyl stearate, hexyl laurate, dibutyl adipate, ceteryl isononanoate, decyl oleate, oleyl erucate, caprylic / capric triglycerides, dicapryl ether and/or dioctylcyclohexanes.

Further oils which can be used according to the invention are known from DE 101 56 674, page 6, lines 9 to 59.

An optionally desired oil component of the cosme|tic or dermatological cleansing preparations - - within the scope of the present invention is advantageously selected from the group of the esters of saturated and/or unsaturated, branched and/or unbranched alkanecarboxylic acids having a chain length of from 3 to 30 carbon atoms and saturated and/or unsaturated, branched and/or unbranched alcohols having a chain length of from 3 to 30 carbon atoms, from the group of the esters of aromatic carboxylic acids and saturated and/or unsaturated, branched and/or unbranched alcohols having a chain length of from 3 to 30 carbon atoms. Such ester oils may then advantageously be selected from the group isopropyl myristate, isopropyl palmitate, isopropyl stearate, isopropyl oleate, n-butyl stearate, n-hexyl laurate, n-decyl oleate, isooctyl stearate, isononyl stearate, isononyl isononanoate, 2-ethylhexyl palmitate, 2-ethylhexyl laurate, 2-hexyldecyl stearate, 2-octyldodecyl palmitate, oleyl oleate, oleyl erucate, erucyl oleate, erucyl erucate and synthetic, semi-synthetic and natural mixtures of such esters, for example jojoba oil.

The oil component can advantageously be selected further from the group of the branched and unbranched hydrocarbons and waxes, the silicon oil, the dialkyl ethers, the group of the saturated or unsaturated, branched or unbranched alcohols, as well as the fatty acid triglycerides, specifically the triglycerol esters of saturated and/or unsaturated, branched and/or unbranched alkanecarboxylic acids having a chain length of from 8 to 24, especially from 12 to 18 carbon atoms. The fatty acid triglycerides can advantageously be selected, for example, from the group of the synthetic, semi-synthetic and natural oils, for example olive oil, sunflower oil, soybean oil, groundnut oil, rapeseed oil, almond oil, palm oil, coconut oil, palm-kernel oil and the like.

Any desired blends of such oil and wax components can also advantageously be used within the scope of the present invention. It may also be advantageous to use waxes, for example cetyl palmitate, as the only lipid component in the oil phase.

The oil component is advantageously selected from the group 2-ethylhexyl isostearate, octyl dodecanol, isotridecyl isononanoate, isoeicosan, 2-ethylhexyl cocoate, Ci₂-i₅-alkyl benzoate, caprylic/capric acid triglyceride, dicaprylyl ether.

Mixtures of Ci₂-i₅-alkyl benzoate and 2-ethylhexyl isostearate, mixtures of Ci₂-i₅-alkyl benzoate and isotridecyl isononanoate and mixtures of Ci₂-i₅-alkyl benzoate, 2-ethylhexyl isostearate and isotridecyl isononanoate are particularly advantageous. Of the hydrocarbons, paraffin oil, squalane and sgualene are advantageously to be used within the scope of the present invention.

Advantageously, the oil component may also have a content of cyclic or linear silicone oils or may consist entirely of such oils, it being preferable, however, to use an additional content of other oil-phase components in addition to the silicone oil or silicone oils.

Cyclomethicone (octamethylcyclotetrasiloxane) is advantageously employed as the silicone oil to be used according to the invention. However, other silicone oils are also advantageously to be used within the scope of the present invention,¹ for example hexamethylcyclotrisiloxane, polydimethylsiloxane, poly(methylphenylsiloxane) .

Mixtures of cyclomethicone and isotridecyl isononanoate and mixtures of cyclomethicone and 2-ethylhexyl isos,tearate are also particularly "advantageous.

The oil component is also advantageously selecte Id from the group of the phospholipids. The phospholipids are phosphoric acid esters of acylated glycerols. Of very great importance among the phosphatidyl cholines are, for example, the lecithins, which are distinguished by the general structure

0 CH₂-O-C-R"

R-C-O-CH CH,

CH₂-O-P-O-CH₂-CH₂-N⁺-CH₃

^ϋ CH₃ wherein R and R" typically represent unbranched aliphatic radicals having 15 or 17 carbon atoms and up to 4 cis-double bonds. According to the invention, the oils can be used on their own or in the form of a mixture.

The cosmetic composition may be, for example, a soap; a soapless washing agent; a liquid washing or showering preparation; a bath additive; a make-up remover; a peeling, preparation; a skin cream; a skin lotion; a face mask; a foot care agent; a sun protection agent; a skin-tanning agent; a depigmenting agent; an insect repellent; a wet-shaving agent, such as, for example, a stick, a cream, a gel or a foam; a pre-shave preparation; an after-shave care agent; a hair-removing agent; a tooth cream; a hair shampoo; a hair care agent, such as, for example, a hair treatment, a rinse or a conditioner; a perming agent; a smoothing agent, a style-fixing agent, such as, for example, a setting lotion, a hairspray, a hair lacquer, a hair gel or a hair wax; an agent for changing the colour of the hair, such as, for example, a bleaching agent, a hair dye, a tint or a colour fixing agent; a deodorant or antiperspirant, such as, for example, a stick, a roll-on, a lotion, a powder or a spray; facial make-up, such as, for example, a tinted day cream, a powder cream, a face powder, a cream make-up or a rouge; eye make-up, such as, for example, an eye shadow, a mascara, a kohl pencil, an eyeliner or an eyebrow pencil; a lip care agent; a decorative lip care agent, such as, for example, a lipstick, a lip gloss or a lip contour pencil; or a nail care agent, such as, for example, a nail varnish, a nail varnish remover, a cuticle remover, a nail hardener or a nail care cream.

The pharmaceutical preparations may be any desired solid, semi-solid or liquid pharmaceutical dosage forms, preferably for oral and/or topical administration, such as, for example, suspensions, emulsions, aerosols, ointments, creams, gels, pastes, suppositories, sticks, powders, granules, tablets, pastilles, dragees, film-coated tablets, hard gelatin capsules, soft gelatin capsules, extrudates, microcapsules or microspherules. Particular preference is given to solid pharmaceutical dosage forms, such as, for example, powders, granules, tablets and capsules. The term "pharmaceutical composition" within the scope of the present invention also includes preliminary and intermediate products for the preparation of granules, tablets, capsules, suspensions, dried juices and dried drops. Such preliminary and intermediate products may be, for example, in the form of a powder, granules or an extrudate.

Methods for the preparation of solid, semi-solid and liquid pharmaceutical dosage forms are known and are described in many publications and textbooks of pharmaceutical technology, see, for example, K.H. Bauer, K.-H. Frδmming, C. Fiihrer, Lehrbuch der pharmazeutischen Technologie, 6th Edition, Wissenschaftliche Verlagsgesellschaft mbH Stuttgart 1999. .. i

Examples

General procedure (preparation) and measurement by means of MCR 300 rheometer composition of the dispersion.

Model presentations for the interpretation of oscillation measurements on AEROSIL-thickened systems (amplitude sweep)

The AEROSIL-thickened dispersions are investigated inter alia by oscillation measurements, specifically in the amplitude sweep, using a Physica MCR300 rheometer. During the amplitude sweep, the excursion of the oscillating measurement body is continuously increased and the structure of the AEROSIL network is accordingly expanded. This increase in the excursion is continued until the lattice structure collapses. By means of this type of measurement it is possible to determine the so-called linear viscoelastic range (LVE) , which is a measure of the stability of the sample. It can also be used to determine the structural strength of the sample in the state of rest. Various, in some cases calculated, parameters are obtained from the measurement. A precise definition of the parameters will be found in the rheology manual "Rheologie" , Lotter Gehn 1998, Vincent- Verlag. These parameters are listed hereinbelow and explained by way of example by transfer to the model of a spring.

- Storage modulus (unit Pa) : Corresponds to the stored portion of the introduced energy in the linear viscoelastic range. In the spring model, the storage modulus would correspond to the spring constant.

- Loss modulus (unit Pa) : Corresponds to the proportion of the introduced energy in the linear viscoelastjic range that is not stored and is consumed by movement.

- Yield point (unit Pa) : In real systems, there is a yield zone. In order to simplify handling, the tests use the yield point. The yield point corresponds to the force which must be applied in order to destroy the structure of the present system. In conformity with the general procedure (literature, equipment manufacturers) , a reduction in the storage modulus of 5 % is defined as the critical limiting value. In the spring model, this value would correspond to the upper limiting value of the linear spring behaviour. Outside this range, the spring travel does not increase linearly with the applied external force, which results in destruction of the spring. The yield point is critical for the stabilising action of the network formed by the pyrogenically prepared silicas (AEROSIL network) . It can, as a force, be converted directly into a stabilisable particle size (with a defined density) (Figure 1) .

- Critical deformation (unit %) : This is a measure of the elasticity or brittleness of the sample. This value represents the deformation at the time of collapse of the structure (definition: see yield point) . In the spring model, this value would correspond to the maximum extensibility of a spring in the linear range (see explanation under "Yield point").

- Loss factor (dimensionless) : This is defined by the ratio of loss modulus through storage modulus.

Preparation of the aerosil dispersions

- Weighing of soybean oil acid methyl ester (Agnique 2237, Cognis) + surfactant into a 250 ml glass bottle.

Dissolution of the surfactant, swinging of the bottle (for quantities see Table 1) .

- Addition of Aerosil^® R974, brief swinging to wet the silica

- Dispersion with Ultra Turrax T25 basic, shear head S 25 N 18 G. Time 15 min, speed 16,000 rpm. During shearing, the glass bottle is located in a water bath adjusted to a temperature of 25°C.

Degassing of the dispersion in vacuo.

- Measurement of the freshly prepared samples in oscillation using a MCR300 rheometer (as described below) . Measurement using a MCR 300 rheometer (oscillation measurement)

Oscillation measurements (storage modulus, yield point, critical deformation)

After being introduced into the measuring system, the samples are subjected to a defined stress in a preliminary shear procedure (constant frequency 1 Hz, constant temperature 23⁰C) and measured immediately thereafter.

Deformation {%) Duration (sec)

Cycle 1 100 120

Cycle 2 0.08 60

Cycle 3 100 120

Cycle 4 0.08 60

Cycle 5 100 I 20

Cycle 6 0.08 i 60

Cycle 7 100 20

Cycle 8 0.08 420

Cycle 9 Start of the actual measurement

Cycle 9 is an amplitude sweep with the following fixed measuring parameters:

Measuring system: DG.26.7 Measuring points 30 (without specified times)

Deformation: Frequency: 1 Hz Amplitude gamma: 0 . 008 % - 100 % Temperature: 23°C The storage modulus behaviour in the linear viscoelastic range (LVR) and yield point are evaluated.

The Pluriol surfactants used are:

Pluriol P grades

Chemical nature: polypropylene glycols of the general formula HO(CH-CH₂O)_nH

CH₃ The degree of polymerisation n and hence the mean molar mass determine the properties of the individual grades.

Properties

Pluriol Method Unit P 2000 P 4000

Supplied form liquid liquid

Appearance at 23°C colourless to weakly yellow colourless to weakly yellow

Mean molar mass ver. OH number g/mol about 2000 about 4000

Concentration about 100 about 100

Density at 23°C DIN 51757 g/cm³ about 1.0 about 1.0

Pour point DIN 51583 °C about -35 about -35

Kinematic viscosity

at 20°C mm² /s about 440 about 1050 at 40°C mm² /s about 150 about 360 at 98 . 9°C mm² /S -about- 23 about 190

Solubility and irascibility

The Pluriol P grades are clear liquids which are miscible with organic solvents, for example ethanol, toluene and trichloroethylene, in any ratio.

Pluriol P 2000 and Pluriol P 4000 are likewise miscible with most mineral oils in any ratio.

Pluronic PE 10500 is a wax-like, non-ionic surfactant which is prepared by copolymerisation of propylene oxide and ethylene oxide. As the following diagrammatic structural formula shows, the Pluronic PE grades are block polymers in which polypropylene glycol forms the central molecular part:

CH₃

HO(CH₂CH₂O)jc(CHCH₂Oy(CH₂CH₂O)_ZH

Pluronic PE 10500

Molar mass, calculated, from OH number g/mol. about 6500

Concentration about 100

Turbidity point (DIN 53917 BDG ⁰C water ⁰C > 100 NaCl solution ⁰C about 75 pH value (5 % in water) about 7

Density (23°C) g/cm³ about 1.03 (60⁰C)

Bulk density g/i

Viscosity (23⁰C, Brookfield, 60 rpm) iriPa- s

Pour point ⁰C

Melting point ⁰C about 44

Wetting action (DIN 53901, 23°C, about 300 2 g soda/1 of dis . water, 1 g/1) s

Surface tension about 39 (DIN 53914, 23⁰C, 1 g/1 of dist. water) mN/m

The Pluronic PE grades have a four- or five-figure number for identification purposes. In the case of four-figure numbers, the first figure is the key for the approximate molar mass of the hydrophobic polypropylene glycol block; in the case of five-figure numbers, this is indicated by the first two figures. The following figure, multiplied by 10, gives the percentage content of polyethylene glycol in the molecule as a whole.

Alkyl Esters

Aerosil ^® R974 is a hydrophobic fumed silica aftertreated with DDS (dimethyldichlorosilane) based on a hydropholic finned silica with a specific surface area of 200 m²/g.

Physico-chemical Data

Properties Unit Typical Value

Specific Surface (BET) mVg 170 ± 20

Carbon content 0.7-1 .3

Average primary particle nm 12 size

Tapped density (approx. g/1 about 50 value)* ace. to DIN ISO 787/XI, Aug. 1983

Moisture * ≤ 0 . 5

2 hours at 105°C

Ignition loss 2 hours at 1000°C based on material dried for 2 hours < 2 . 0 at 105°C

pH-value 3 . 7-4 . 7 in 4 % dispersion

SiO₂-content ( 1 ) ( 1 ) based on ignited > 99 . 8 material

* ex plant

The data represent typical values and not production parameters Test composition

without surfactant Pluronic PE10500 (mmol. ) Pluriol P4000 (mmol. ) Pluriol P2000 (mmol.)

0.085 0.015 0.054 0.025 0.0625 0.0665 0.16

Storage modulus (PA) not determinable 28.319 44.542 88.453 32.99 50.302 24.495 30.849

Loss factor not determinable 0.121 0.119 0.112 0.18 0.186 0.198 0.2

Yield point (Pa) not determinable 0.179 0.213 0.332 0.125 0.133 0.126 0.07

Crit. deformation (%) not determinable 0.499 0.402 0.319 0.331 0.21 0.328 0.174

Claims

Patent claims

1. Non-aqueous system having viscoelastic properties, characterised in that it comprises a surface-active substance or a mixture of surface-active substances, an oil component and a pyrogenically prepared silica.

2. Non-aqueous system according to claim 1, characterised in that it exhibits viscoelastic properties characterised by storage modulus, loss modulus, loss factor and yield point.

3. Non-aqueous system according to claim 1, characterised in that the surface-active substance is non-ionic.

4. Non-aqueous system according to claim 2, characterised in that the viscoelastic properties are enhanced by the cooperation of surface-active substances and pyrogenically prepared silica.

I 5. Use of the non-aqueous system having viscoelastic properties in the preparation of emulsions or ] suspensions of active ingredients.

6. Use of the non-aqueous system according to claim 5 in the preparation of stable suspensions of solids.

7. Non-aqueous cosmetic and/or pharmaceutical preparations, consisting of a surface-active substance or a mixture of surface-active substances, an oil component, a hydrophilic and/or hydrophobic pyrogenically prepared silica as well as one or more cosmetically or pharmaceutically relevant auxiliary substances and/or active ingredients.