AU2019261786A1

AU2019261786A1 - Highly Loaded Suspension Concentrates

Info

Publication number: AU2019261786A1
Application number: AU2019261786A
Authority: AU
Inventors: Andrew HORSFIELD; Peter Vaughan
Original assignee: Adama Australia Pty Ltd
Current assignee: Adama Australia Pty Ltd
Priority date: 2018-11-09
Filing date: 2019-11-08
Publication date: 2020-05-28

Abstract

Abstract The invention provides a suspension concentrate formulation which includes more than 400 g/litre of a suitable active ingredient or of a combination of suitable active ingredients; an anionic dispersant; a polymeric stabiliser; a rheology modifier; and 5 water. Examples of active ingredient are iprodione, methoxyfenozide, propyzamide, tebuconazole, azoxystrobin and a combination of tebuconazole and azoxystrobin. 10 The invention also provides methods for determining whether a selected active ingredient is suitable for formulation as an aqueous suspension concentrate.

Description

Highly Loaded Suspension Concentrates

Technical Field

The invention relates to novel formulations for highly loaded suspension concentrates. In the description below, the invention is discussed in relation to highly loaded formulations suitable for a range of active ingredients for agricultural use. However, it is to be understood that the scope of the invention is not limited to agrochemicals.

Background

High concentration formulations are generally desirable for agricultural use. A highly loaded formulation can deliver the required quantity of active ingredient to a user in a smaller volume, saving packaging, freight costs, storage volume and energy costs and reducing waste. Higher concentration formulations also reduce the quantity of formulated product required to be produced by formulators.

A suspension concentrate (SC) formulation contains one or more solid active ingredients dispersed in water. SC formulations can be cost effective for a range of active ingredients with low water solubility. SC formulations are regarded as easy to use, because of absence of dust compared to a wettable power (WP) formulation, for example. However, an SC formulation must be stable, so that the active ingredient/s remains in suspension in a range of conditions, usually mandated by a relevant authority, such as Australian Pesticides and Veterinary Medicines Authority (APVMA).

Typically, SC formulations contain water, the active ingredient(s), dispersants/ adjuvants to ensure a stable suspension of the active ingredient and other materials such as antifoam and antimicrobial compounds.

While highly loaded SC formulations are desirable, as set out above, problems can arise in obtaining an acceptable formulation. The use of water as a carrier is desirable as it is an inexpensive and non-toxic solvent. The amount of water and other materials required to effectively suspend an active ingredient in an SC formulation can determine the maximum concentration of the formulation. The majority of current

2019261786 08 Nov 2019 agrochemical SC formulations are relatively lowly loaded - often <500 g active ingredient /Litre, compared with other formulations that form a dispersion/suspension on dilution with water for application by the end user, such as water dispersible granules (WG's), where >800 g active ingredient/kg is often possible, depending on the active ingredient.

There are some examples of higher loaded SC formulations such as chlorothalonil at >720 g/L, metamitron at 700 g/L and some seed treatment formulations of imidacloprid at 600 g/L. However, for most active ingredients, the maximum loading available in a stable SC formulation is significantly lower.

In addition, for some active ingredients a 'highly loaded' suspension concentrate formulation would involve a concentration less than 500 g active ingredient/Litre. An example is methoxyfenozide, which is currently commercially available in a concentration of only 240 g/L.

Summary of the Invention

In a theory proposed by the inventors, in order to produce a stable suspension concentrate, the maximum volume occupied by the dispersed phase in suspension concentrate formulations is limited to about 520 mL. This conversely allows for a minimum volume of about 480 mL for the continuous phase (water plus excipients). In experimenting with this theory, it has been discovered that the maximum dispersed 20 phase loading which can be achieved in suspension concentrate formulation, in order that there is sufficient volume of the continuous phase to make the composition flowable, is primarily a factor of the density of the dispersed phase under consideration.

In this specification and claims, 'density' means crystalline density. Usually, crystalline 25 density is theoretically calculated or derived from X-Ray Diffraction (XRD) data, which can provide crystal structure and unit cell parameters. 'Unit cell' means the simplest repeating unit in a crystal and is defined in terms of lattice points, being the points in space about which the particles are free to vibrate in a crystal. The molecular arrangement of a crystal ultimately determines the weight and volume of the unit cell.

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The parameters of crystal structure and unit cell are used to calculate unit cell volume and how many molecules are present in every unit cell. The formula for the calculation of density is given by:

Crystalline Density = (Molecular weight x No. of molecules per unit cell) / Volume of the unit cell x Avogadro's number).

The proposed theory is based upon consideration of certain commercially successful suspension concentrate formulations, as well as by development and study of several highly loaded prototypes and by experimentation with agricultural active ingredient dispersed phases of varying density and chemistry. Examples are set out below in Table A. The formulations which were developed by the inventors are indicated by '625 prototype developed'. It is to be understood that the loading of 625 g/L does not indicate that this is a maximum loading for the active ingredients listed. The loading of 625 g/L was selected as a commercially useful loading, being easy for users to measure.

TABLE A

Compound	Density	Loading g/L	Continuous Phase	Dispersed Phase
Chlorothalonil	1.80	720 commercial product	600.0 mL	400.0 mL
Iprodione	1.40	625 prototype developed	553.6 mL	446.4 mL
Azoxystrobin	1.33	625 prototype developed	530.1 mL	469.9 mL
Tebuconazole	1.25	625 prototype developed	500 mL	500.0 mL
Propyzamide	1.21	625 prototype developed	483.5 mL	516.5 mL
Diafenthiuron	1.07	600 unsuccessful	439.3 mL	560.7 mL

Compound	Density	Loading g/L	Continuous Phase	Dispersed Phase
Diafenthiuron		500 commercial product	532.7 mL	467.3 mL

The theory and the discovery of the role of density of the dispersed phase considerably assists in formulation of highly loaded SC formulations, enabling the formulator to predict with many active ingredients whether a highly loaded SC formulation is possible. As a result, the formulator can avoid wasting time and resources in experimenting unsuccessfully with many low density active ingredients.

An example is diafenthiuron. As shown in the table above, diafenthiuron is available commercially at a loading of 500 g/L. However, an attempt to formulate diafenthiuron as a suspension concentrate at a loading of 600 g/L failed to produce a stable product. The above table shows that diafenthiuron has low density compared with the other listed active ingredients for which successful highly loaded SC formulations were developed.

Accordingly, in one aspect, the present invention provides a method for determining whether a selected active ingredient is suitable for formulation as an aqueous suspension concentrate having a dispersed phase and a continuous phase where the selected active ingredient is to have a loading of more than about 400 g/L, the method including the steps of:

(a) ascertaining density of the selected active ingredient;

(b) comparing the density of the selected active ingredient with densities of active ingredients for which aqueous suspension concentrate formulations have been successfully developed where the continuous phase has a minimum volume of about 480 mL and the dispersed phase has a maximum volume of about 520 mL; and (c) if the density of the selected active ingredient is comparable with any of the densities of the active ingredients for the said successfully developed aqueous suspension concentrate formulations, formulating

2019261786 08 Nov 2019 the selected active ingredient as an aqueous suspension concentrate at a loading at least as high as that of the loading of the comparable successfully developed aqueous suspension concentrate formulation.

The selected active ingredient may be a single active ingredient or a combination of 5 two or more active ingredients.

In some embodiments, the selected active ingredient is intended to have a loading of more than 500 g/L.

The dispersed phase is generally regarded as the phase in which the selected active ingredient is suspended in the SC formulation while the continuous phase is generally 10 regarded as the phase containing water and excipients.

In general, it can be expected that the higher the density of the selected active ingredient, the higher the loading in the aqueous suspension concentrate formulation.

It will be noted from table A that, generally, as the density of the active ingredient increases, the dispersed phase volume decreases to a minimum of 400 mL while the 75 continuous phase volume increases to a maximum of 600 mL for a successful SC formulation.

In step (c) in the method above, the comparable successfully developed aqueous suspension concentrate formulation is preferably that having a density that is less than but close to that ofthe selected active ingredient.

It has also been discovered that density (or alternately specific gravity) of an active ingredient can be relevant to ascertaining suitability of the active ingredient for formulation as an aqueous suspension concentrate at a relatively high loading. In the description below, density is referred to, rather than specific gravity. However, it is to be understood that specific gravity values can be substituted.

Table B below shows the ratio of certain active ingredient loading to density. Stable SC formulations have been developed successfully for the active ingredients in Table B, at the loading indicated.

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TABLE B

Active Ingredient (Al)	Al Density	Al loading (g ai/L)	Al Loading: Density ratio
Chlorothalonil	1.80	720	400
Iprodione	1.4	625	446
Azoxystrobin	1.33	625	470
Tebuconazole	1.25	625	500
Propyzamide	1.21	625	517
Methoxyfenozide	1.10	480	436
Azoxystrobin Tebuconazole	1.33	222	463
1.25	370

In the case of the co-formulation of azoxystrobin and tebuconazole, the Al loading: density ratio ('Ratio') is calculated according to the formula:

Ratio = (density of Al #l/loading Al #1) + (density of Al #2/loading Al #2) + (density of Al #n/loading Al #n).

In the case of the co-formulation shown, Al #1 is azoxystrobin and Al #2 is tebuconazole.

It will be noted in Table B that the loading of the co-formulation of azoxystrobin and 10 tebuconazole is 592 g ai/L, which is close to the 625 g/L of the solo formulations of each of azoxystrobin and tebuconazole.

It will be appreciated by the person skilled in the art that the Ratio represents the volume occupied by the dispersed phase in the formulation. It is expected that, as the Ratio or dispersed phase volume for a chosen active ingredient approaches the 75 maximum of 520, the ability of the active ingredient to be more highly loaded in a stable SC formulation will be restricted.

For example, in Table B methoxyfenozide has a lower density than the other active ingredients and the loading selected in the prototype (480 g/L) has a Ratio of 436. At a more commercially desirable higher loading of 625 g/L the ratio becomes 570,

2019261786 08 Nov 2019 exceeding the limit of 520. It is therefore expected that a commercially acceptable higher loading of methoxyfenozide of greater than 480 g/L will be difficult to achieve in a stable SC formulation.

Successful aqueous suspension concentrate formulations in Table B have a Ratio of about 520 or less. As already noted above, an aqueous suspension concentrate of diafenthiuron at 600 g/L is not sufficiently stable. The ratio of active ingredient loading to density is well above 520, being 561.

In a second aspect, therefore, this invention provides a method for determining whether a selected active ingredient is suitable for formulation as an aqueous 10 suspension concentrate at a selected loading in g/L, the method including the steps of:

(a) ascertaining density of the selected active ingredient;

(b) calculating ratio of the selected loading to the ascertained density; and (c) if the ratio is less than about 520, formulating the selected active ingredient as an aqueous suspension concentrate at the selected loading.

It will be appreciated that the methods of the invention in each of the first and second aspects can save unnecessary experimentation in the preparation of suspension concentrate formulations, saving time and costs. The methods may be used separately, or together as an aid to avoid or reduce failures in formulating suspension concentrates.

In practicing the method of the invention, it has been found that for some active ingredients, conventional dispersant/surfactant systems may not be appropriate. Whilst the theory supporting the method would favour high density dispersed phases, the propensity for syneresis and sedimentation is increased proportionately to the density of the dispersed phase.

The viscosity of a suspension concentrate at the maximum loading is predicated by the surface chemistry of the dispersed phase and moreover by the high solids content.

Understandably, the highly loaded suspension concentrates are typically more viscous than the lower loaded formulations.

Rheology modifiers are required to structure the continuous phase and therefore limit syneresis and sedimentation in suspension concentrate formulation. Typically, polysaccharide, polymer, mineral clay or modified silicas are used to provide structure to the continuous phase, sufficient to slow sedimentation and syneresis to an acceptable level for a 2-year storage shelf life.

However, it has been found that the addition of rheology modifier to a highly loaded suspension concentrate has the undesirable consequence of a producing too viscous a product, with limited container pourability, insufficient container rinsability and poor spontaneity of dispersion, such that the mandatory industry specification and prescribed testing (CIPAC MT 148 Pourability & CIPAC MT 160 Spontaneity of Dispersion) cannot be achieved.

Distance dependent, attractive interactions between particles, such as van der Waals forces and Brownian motion collisions, are the cause of particle agglomeration and high viscosity in poorly optimized suspension concentrate formulations. In the case of increased loading of the dispersed phase, these interactions are more prevalent, the particles being more abundant and closely packed in a limited continuous phase volume. Therefore, highly loaded SC formulations often display some undesirable rheology and agglomerate more rapidly than more dilute and more typical suspension concentrates.

Dispersants, either electrostatic (anionic) or steric (polymeric) can be used to prevent particle interactions in suspension concentrate formulations and thus limit agglomeration and reduce viscosity. Anionic dispersants, whilst effective, are typically interfered with by spray tank mixed soluble liquid formulation (electrolytes), causing an incompatibility. For this reason, they are generally avoided in favour of polymeric steric dispersants (non-ionic) particularly where the product may be mixed in the spray tank together with electrolytes.

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The surface tension of the dispersed phase must be overcome to replace air and wet the solid particle surface with the continuous phase. An appropriate wetting agent can be critical to the colloid milling stage of the formulation process and together with a humectant prevents skinning or drying out at the liquid-air interface during the 5 manufacturing process and storage. It has been found that the limited continuous phase volume inherent to a highly loaded suspension concentrate makes prevention of skinning and drying out during manufacture and upon storage significantly more challenging.

It has been surprisingly discovered that it is possible to provide certain SC solo and 10 co-formulations that are more highly loaded yet stable, by using a selected combination of anionic dispersant with stabiliser and rheology modifiers, and to meet all prescribed industry specifications.

Accordingly, in a third aspect, the invention provides a suspension concentrate formulation which includes:

(a) more than 400 g/litre of one or more suitable active ingredients;

(b) an anionic dispersant;

(c) a polymeric stabiliser;

(d) a rheology modifier; and (e) water.

Preferably, the suitable active ingredient is chosen from the group consisting of: iprodione, methoxyfenozide, propyzamide, tebuconazole, azoxystrobin and tebuconazole and azoxystrobin as a co-formulation. Other active ingredients that are able to be formulated as an SC are also suitable providing their density is >1.0 and they are compatible with items (b), (c) and/or (d) above.

It is further preferred that the active ingredient is loaded at about 625 g/L or more.

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Examples of anionic dispersants are:

- Soprophor™ FLK, available from Solvay Interox Pty Limited in Australia and described as ethoxylated tristyrlphenol phosphate potassium salt;

- Morwet™ D-425, available from AkzoNobel Surface Chemistry in Australia and described as naphthalenesulfonic acid, polymer with formaldehyde, sodium salt.

The polymeric stabiliser is preferably chosen from:

- Atlox™ 4913-LQ-(NV), available from Croda Crop Care, described as methyl methacrylate - methacrylic acid - monoethoxy polyethylene glycol methacrylate copolymer solution;

- Agrilan™ 755, available from AkzoNobel Surface Chemistry in Australia, described as a proprietary hydrophilic comb polymer (composition undisclosed).

- Stepflow 4000, available from Stepan and described as polymethyl methacrylate-polyethylene glycol graft copolymer;

Examples of rheology modifier are one or more of: Attagel™ 50, available from BASF, described as modified fullers earth; Xanthum gum TFST, available from Jungbunzlauer Austria AG and described as technical grade, fine, salt tolerant xanthum gum; AgRHO Pol 23 W, available from Solvay Interox Pty Limited in Australia and described as 20 xanthum gum.

If desired, the SC formulations of the invention may include other surfactants, such as:

- Atlox™ 4894-LQ-(NV), available from Croda Crop Care, being a wetting agent/stabiliser and described as a nonionic proprietary surfactant blend (composition undisclosed);

- A humectant such as glycerine (propane-1, 2, 3 - triol) BP/EP/USP grade, propylene glycol (propane-1, 2- diol) available from Recochem Inc or mono propylene glycol;

- A preservative such as Proxel™ GXL, available from Lonza Australia Pty Limited and described as aqueous dipropylene glycol solution of 1, 2- benzisothiazolin3-one;

- An antifoam agent such as Gensil™ 2030, available from Solvay Interox Pty Ltd in Australia and described as polydimethysiloxane aqueous emulsion, or SAG 1572, a silicon antifoam emulsion, available from Momentive Performance Materials;

- An emulsifier such as Ethylan™ NS 500 NQ, available from AkzoNobel Surface Chemistry in Australia and described as polyethylene glycol-co-propylene glycol) monobutyl ether.

If required, the pH of the formulation may be adjusted, for example using citric acid.

The active ingredient in the suspension concentrate formulation of the third aspect of the invention preferably is selected according to the method of the invention in its first aspect and/or its second aspect

Detailed Description of Preferred Embodiments

Example 1: SC Formulation of Iprodione

Table 1 below sets out the formulation composition and Table 2 below sets out the component details.

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Table 1 - Formulation Composition

Content g/L	Component	Purpose in Formulation	Supplier
647.6	Iprodione Technical 96.5%	active ingredient	Jiangsu Kuaida Agrochemical Co. Ltd
25.0	Morwet™ D-425	dispersant	AkzoNobel Surface Chemistry
10.0	Ethylan™ NS500NQ	emulsifier	AkzoNobel Surface Chemistry
6.5	Agrilan™ 755	stabiliser, dispersant	AkzoNobel Surface Chemistry
80.0	Propylene Glycol	humectant	Recochem Inc
1.93	AgRHO Pol 23 W	rheological additive	Solvay Interox Pty Ltd
2.0	Proxel GXL 20	preservative	Lonza Australia Pty Ltd
0.3	Citric Acid	pH adjustment	Ixom Operations Pty Ltd
0.4	Gensil 2030	antifoam	Solvay Interox Pty Ltd
438.6	Water	diluent	Potable water source

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Table 2 - Component Details

Trade Name	IUPAC NAME	CAS#
Iprodione Technical 96%	3-(3,5 -dichlorophenyl)-2,4-dioxo-N- propan-2-ylimidazolidine-l-carboxamide	36734-19-7
Morwet™ D-425	naphthalenesulfonic acid, polymer with formaldehyde, sodium salt	9084-06-4
Ethylan™ NS 500 NQ	polyethylene glycol-co-propylene glycol) monobutyl ether	9038-95-3
Agrilan™ 755	proprietary hydrophilic comb polymer, composition undisclosed	N.A.
Propylene Glycol	propane-1,2-diol	57-55-6
AgRHO Pol 23 W	xanthum gum	11138-66-2
Proxel GXL 20	aqueous dipropylene glycol solution of 1, 2- benzisothiazolin-3-one	2634-33-5
Citric Acid	2-hydroxypropane-l, 2, 3-tricarboxylic acid	77-92-9
Gensil 2030	polydimethylsiloxane aqueous emulsion	63148-62-9
Water	water	7732-18-5

Method:

The required amount of Ethylan NS 500 LQ was melted in a water bath at 60°C and maintained in a completely molten state prior to addition.

Next 90% of the water was charged into a suitable vessel equipped with a high shear saw tooth impeller. While continuing to mix, the following were added in sequence: the citric acid, 90% of the propylene glycol, 50% of the Gensil 2030, the Morwet™ D425, the Ethylan NS 500 LQ, the Agrilan™ 755 and the iprodione technical.

The mixture was dispersed on high speed for 30 minutes, then bead milled by recirculation through a Dyno™ KD grinding mill or equivalent, until a Malvern™ measured mean particle size of between < 3.0 microns and 90% < 8.0 microns was achieved.

The milled base was then transferred into a suitable vessel equipped with a stirrer.

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The remaining propylene glycol, AgRHO Pol 23 W and Proxel GXL were premixed in a suitable vessel and added to the milled base. While continuing to mix, the remaining water and Gensil 2030 were added. Mixing was continued on a slow speed for a further 60 minutes, until the AgRHO Pol 23 W was completely hydrated and dispersed.

The active ingredient content was confirmed by the analytical method QCM-127.01; the active ingredient content was adjusted with water as required.

Product Specification and Analysis:

5000 mL of the formulation was prepared by the above method and analysed and tested as set out in Table 3 below. The active ingredient iprodione was present in the amount of 626 g/L and the formulation passed the required tests, including pourability, suspensibility, spontaneity of dispersion and viscosity.

Table 3: Product Specification and Analysis

Determination	Method	Specification	Analysis	Result
Appearance, physical state and colour	Visual	Beige suspension	Beige suspension	PASS
Odour	Olfactory	Characteristic	Characteristic	PASS
pH-1% v/v dilution	CIPAC MT 75.3	3.5-6.0	4.26	PASS
Density @ 20°C	CIPAC MT 3.3.2	1.203-1.213 g/mL	1.208 g/mL @ 20°C	PASS
Pourability 700 mL Kilner jar	CIPAC MT 148	< 5% residue < 0.25% rinsed residue	2.78% residue 0.19% rinsed residue	PASS

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Determination	Method	Specification	Analysis	Result
Suspensibility Standard water D	CIPAC MT 184 2.0 g/250 mL	>60% and <105% after 30 minutes	90%	PASS
Spontaneity of dispersion Standard water C	CIPAC MT 160 12.5 ml/250 mL	>60% and <105% after 5 minutes	94%	PASS
Wet sieve test	CIPAC MT 185 75 μιτι sieve	< 2.0%	<0.01%	PASS
Viscosity @ 20°C Brookfield RVT	CIPAC MT 192 SPD 2 20 rpm	600-800 cps	740 cps	PASS
Persistent foam Standard water C	CIPAC MT 47.2 2.0g/200mL	Max 60 mLfoam after 1 minute	Initial: 42 mL After 10 sec: 30 mL After 1 min: 16 mL After 3 min: 9 mL After 12 min: 5 mL	PASS
Content iprodione	QCM-127.01	600-650 g/L	626 g/L	PASS

Example 2: SC Formulation of Azoxystrobin

Table 4 below sets out the formulation composition and Table 5 below sets out the component details.

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Table 4 - Formulation Composition

Content g/L	Component	Purpose in Formulation	Supplier
637.8	Azoxystrobin Technical 98%	active ingredient	Approved Source
25.0	Morwet™ D-425	dispersant	AkzoNobel Surface Chemistry
10.0	Ethylan™ NS 500 NQ	emulsifier	AkzoNobel Surface Chemistry
10.0	Agrilan™ 755	stabiliser, dispersant	AkzoNobel Surface Chemistry
80.0	Propylene Glycol	humectant	Recochem Inc
2.0	AgRHO Pol 23 W	rheological additive	Solvay Interox Pty Ltd
2.5	Proxel GXL 20	preservative	Lonza Australia Pty Ltd
1.5	Gensil 2030	antifoam	Solvay Interox Pty Ltd
413.2	Water	diluent	Potable water source

Table 5 - Component Details

Trade Name	IUPAC NAME	CAS#
Azoxystrobin Technical 98%	methyl (2E)-2-(2-{[6-(2-cyanophenoxyl) pyrimidin-4-yl]oxy}phenyl)-3methoxyacrylate	131860-33- 8
Morwet™ D-425	naphthalenesulfonic acid, polymer with formaldehyde, sodium salt	9084-06-4
Ethylan™ NS 500 NQ	poly(ethylene glycol-co-propylene glycol) monobutyl ether	9038-95-3

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Trade Name	IUPAC NAME	CAS#
Agrilan™ 755	proprietary hydrophilic comb polymer, composition undisclosed	N.A.
Propylene Glycol	propane-1,2-diol	57-55-6
AgRHO Pol 23W	xanthum gum	11138-66-2
Proxel GXL 20	aqueous dipropylene glycol solution of l,2-benzisothiazolin-3-one	2634-33-5
Gensil 2030	polydimethylsiloxane aqueous emulsion	63148-62-9
Water	potable water	7732-18-5

Method:

Next the water was charged into a suitable vessel equipped with a high shear saw 5 tooth impeller. While continuing to mix, the following were added in sequence: 80% of the propylene glycol, 50% of the Gensil 2030, the Morwet™ D-425, the Ethylan NS 500 LQ and the azoxystrobin technical.

The mixture was dispersed on high speed for 30 minutes, then bead milled by recirculation through a Dyno™ KD grinding mill or equivalent, until a Malvern™ 10 measured mean particle size of between < 3.0 microns and 90% < 8.0 microns was achieved.

While mixing, the Agrilan™ 755 was added.

The remaining propylene glycol, AgRHO Pol 23 W and Proxel GXL were premixed in a suitable vessel and added to the milled base. While continuing to mix, the remaining

Gensil 2030 was added. Mixing was continued on a slow speed for a further 60 minutes, until the AgRHO Pol 23 W was completely hydrated and dispersed.

The active ingredient content was confirmed by the analytical method QCM-126.01; the active ingredient content was adjusted with water as required.

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Example 3: SC Formulation of 625 g/L Tebuconazole

Table 6 below sets out the formulation composition.

g/L	Component Trade Name	Purpose	Chemistry Description
634.50	Tebuconazole Technical 98.5%	active ingredient
50.00	Soprophor™ FLK	anionic dispersant	ethoxylated tristyrlphenol phosphate potassium salt
20.00	Atlox™ 4894-LQ-(MV)	wetting agent, stabilizer	nonionic proprietary surfactant blend, composition undisclosed
30.00	Atlox™ 4913-LQ-(MV)	steric stabilizer	methyl methacrylatemethacrylic acidmonomethoxy polyethylene glycol methacrylate copolymer solution
6.93	Attagel™ 50	rheology modifier	modified fullers earth
50.00	Glycerine BP/EP/USP Grade	humectant	propane-1,2,3-triol
0.80	Xanthum Gum TFST	rheology modifier	xanthum gum (technical grade, fine, salt tolerant)
1.50	Proxel™ GXL	preservative	aqueous dipropylene glycol solution of 1,2benzisothiazolin-3-one
1.50	Gensil™ 2030	antifoam	polydimethysiloxane aqueous emulsion
340.69	Potable water	diluent

This formulation was prepared using the same general method as for Examples 1 and 2 above.

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Example 4: SC Formulation of 370 g/L Tebuconazole + 222 g/L Azoxystrobin

Table 7 below sets out the formulation composition.

Table 7

g/L	Component Trade Name	Purpose	Chemistry Description
375.38	Tebuconazole Technical 98.5%	active ingredient
225.88	Azoxystrobin Technical 98.2 %	active ingredient
50.00	Soprophor™ FLK	anionic dispersant	ethoxylated tristyrlphenol phosphate potassium salt
20.00	Atlox™ 4894-LQ-(MV)	wetting agent, stabilizer	nonionic proprietary surfactant blend, composition undisclosed
30.00	Atlox™ 4913-LQ-(MV)	steric stabilizer	methyl methacrylatemethacrylic acidmonomethoxy polyethylene glycol methacrylate copolymer solution
6.93	Attagel™ 50	rheology modifier	modified fullers earth
50.00	Glycerine BP/EP/USP Grade	humectant	propane-1,2,3-triol
0.80	Xanthum Gum TFST	rheology modifier	xanthum gum (technical grade, fine, salt tolerant)
1.50	Proxel™ GXL	preservative	aqueous dipropylene glycol solution of 1,2benzisothiazolin-3-one
1.50	Gensil™ 2030	antifoam	polydimethysiloxane aqueous emulsion
391.43	Potable water	diluent

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This formulation was prepared using the same general method as for Examples 1 and

2.

The embodiments described above relate to preferred embodiments of the various aspects of the invention only and are given by way of illustration. Changes, 5 modifications and variations may be made without departing from the spirit and scope of the present invention.

Claims

Claims

1. A suspension concentrate formulation which includes:

(a) more than 400 g/litre of a suitable active ingredient or of a combination of suitable active ingredients;

(b) an anionic dispersant;

(c) a polymeric stabiliser;

(d) a rheology modifier; and (e) water.
2. The suspension concentrate formulation of claim 1, wherein active ingredient is chosen from the group consisting of: iprodione, methoxyfenozide, propyzamide, tebuconazole, azoxystrobin and a combination of tebuconazole and azoxystrobin.
3. The suspension concentrate of claim 1 or 2, wherein the active ingredient or combination of active ingredients is present at about 625 g/mL.
4. The formulation of any one of claims 1 to 3, wherein the anionic dispersant is an ethoxylated tristyrylphenol phosphate or salt thereof.
5. The formulation of any one of claims 1 to 4, wherein the polymeric stabiliser is a polymethyl methacrylate-polyethylene glycol graft copolymer.
6. The formulation of any one of claims 1 to 4, wherein the polymeric stabiliser is a methyl methacrylate-methacrylic acid-monomethoxy polyethylene glycol methacrylate copolymer.
7. The formulation of any one of claims 1 to 6, wherein the rheology modifier is a clay or silica based colloid or xanthum gum or a combination thereof.
8. The formulation of any one of claims 1 to 7, which includes an emulsifier.
9. The formulation of claim 8, wherein the emulsifier is or contains polyalkoxylated butyl ether.
10. A method for determining whether a selected active ingredient is suitable for formulation as an aqueous suspension concentrate having a dispersed phase and a continuous phase, where the selected active ingredient is to have a loading of more than about 400 g/L, the method including the steps of:

(a) ascertaining density of the selected active ingredient;

(b) comparing the density of the selected active ingredient with densities of active ingredients for which aqueous suspension concentrate formulations have been successfully developed where the continuous phase has a minimum volume of about 480 mL and the dispersed phase has a maximum volume of about 520 mL; and (c) if the density of the selected active ingredient is comparable with any of the densities of the active ingredients for the said successfully developed aqueous suspension concentrate formulations, formulating the selected active ingredient as an aqueous suspension concentrate at a loading at least as high as that of the loading of the comparable successfully developed aqueous suspension concentrate formulation.
11. The method of claim 10, wherein the formulated aqueous suspension concentrate is the formulation claimed in any one of claims 1 to 9.
12. The method of claim 10, wherein the density of the selected active ingredient is within the range of >1.0 to 1.8.

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13. A method for determining whether a selected active ingredient is suitable for formulation as an aqueous suspension concentrate at a selected loading in g/L, the method including the steps of:

(a) ascertaining density of the selected active ingredient;

5 (b) calculating ratio of the selected loading to the ascertained density; and (c) if the ratio is less than about 520, formulating the selected active ingredient as an aqueous suspension concentrate at the selected loading.
14. The method claimed in claim 13, wherein the formulated aqueous suspension

10 concentrate is the formulation claimed in any one of claims 1 to 9.
15. The method claimed in claim 13 or 14, wherein the ratio is between 400 and 520.