STABLE AGROCHEMICAL COMPOSITION

FIELD OF THE INVENTION:

The present invention is to provide stabilized agrochemical composition with non-hazardous solvents. In a particular aspect of present invention relates to an emulsion composition comprises of an organo-phosphorus active ingredient or its combination with a pyrethroid active ingredient, surfactant, stabilizer, aqueous medium, optionally one or more green oil or auxiliary agent.

BACKGROUND OF THE INVENTION:

Pests can have an adverse and damaging impact on agricultural production by affecting crops production. Also, pests have a detrimental effect on the environment and human health. To control pests, several organo -phosphorous or pyrethroid pesticides have been developed and are currently in use e.g. profenofos, ethion, or cypermethrin. However, such insecticides need a suitable insecticidal formulation to be used for the treatment of pests of crop plant without causing any harm to the respective environment.

Organo-phosphorus active ingredients are esters of phosphoric acid. Profenofos (shown in Figure 1), and ethion represent a class of organo-phosphorus broad-spectrum insecticides known for its high efficacy, systemic absorption and low residue.

Profenofos is an acetyl cholinesterase inhibitor that produces contact and stomach toxicity in the pests. It is chemically known as 4-bromo-2-chloro-l-[ethoxy(propylsulfanyl)phosphoryl] oxybenzene and was first described in U.S. patent 3,992,533, which is assigned to Ciba-Geigy Corporation. It is used for the treatment of the pests on a variety of crops namely cotton, tea, tobacco, maize, potato, soybean, sugar beet and vegetables. It is used mainly on the cotton crop plant against aphids, jassids or lepidopteran pests. It is effective against organo-phosphorous and pyrethroid-resistant cotton pests. It has the following structure:

Figure 1

Pyrethroid active ingredients are synthetic derivatives of pyrethrins. Pyrethroid active ingredients have been found to give excellent control of pests of the order of Lepidoptera. Cypermethrin represents a class of pyrethroid insecticides.

Pesticidal emulsion formulation is used worldwide as they are simple to handle and convenient to dispense in the field, mainly as a spray with water. U.S. patent application 20020098221 discloses the general method of preparation of oil in water emulsion of pyrethroid insecticides. Chinese patent application 102326580 discloses profenofos emulsion in water which comprises of profenofos, surfactant, water and co-solvent as toluene and xylene. Chinese patent 101606517 discloses an aqueous pesticidal emulsion formulation of profenofos that contains a-pinene, D-limonene and jatropha oil methyl ester as a solvent.

Organo-phosphorus active ingredient such as profenofos and ethion; pyrethroid active ingredient such as cypermethrin are available as an emulsifiable concentrate (EC) formulation.

In general, organo-phosphorus active ingredient based pesticide has very low water solubility and low half-life in water (DT50). In most of the cases these DT50 values are sensitive to pH. Organo-phosphorus active ingredients tend to have lowest DT50 values at pH > 7.

Under these circumstances with low DT50 value, developing aqueous based formulation with shelf-life < 2 years is challenging as activity of organo-phosphorus active ingredients decrease rapidly.

The need of making aqueous based formulation arises from the fact that in the conventional EC formulations large amount of hydrocarbons, which are atmospheric contaminants and are carcinogenic to birds and mammals. Low biodegradability makes them unfavorable in context to safety and sustainability of the environment and earth.

Because of the degradation issues, it is technically essential to develop technologies and identify suitable stabilizers to prevent such degradation in organo-phosphorus active ingredients.

Inventors of present invention surprisingly found that urea and its derivative; several amines can prevent such degradation of organo-phosphorus active ingredients.

Moreover, the solvents conventionally used in such EC formulation are mainly aromatic hydrocarbons namely toluene and xylene. Such solvents are known to adversely impact the environment and hence fail to meet the requirements and trends of sustainable agricultural practices. Use of organic solvents is known to be a health hazard as these solvents are known to be carcinogenic and toxic to mammals including humans.

The object of the present invention is to provide stabilized agrochemical composition with non-hazardous solvents such as aqueous formulation, which is safe and free from hazardous volatile organic solvents like toluene and/or xylene, is effective in controlling pests, and which has advantageous properties that overcome the above mentioned shortcoming.

SUMMARY OF THE INVENTION

In one aspect, the present invention relates to a method of stabilizing an agrochemical composition comprising of:

a) addition of one or more agrochemical active ingredient;

b) addition of one or more stabilizer;

c) optionally addition of one or more surfactant;

d) optionally addition of an aqueous medium;

e) optionally addition of one or more green oil or auxiliary agent;

wherein the stabilizer is selected from the group comprising of urea or its derivatives , triethanolamine, cocoamine, hexamine, tallowamine, epoxidized plant oil, p-anisaldehyde or a combination thereof.

In a further aspect, the present invention relates to an emulsion composition comprising:

a) one or more organo-phosphorus active ingredient,

b) one or more surfactant,

c) one or more stabilizer,

d) an aqueous medium,

e) optionally one or more green oil or auxiliary agent,

wherein the stabilizer is selected from the group comprising of urea or its derivatives, triethanolamine, cocoamine, hexamine, tallowamine, epoxidized plant oil, p-anisaldehyde or a combination thereof.

In another aspect, the present invention relates to an emulsion composition comprising:

a) one or more active ingredient in combination is selected from the group comprising of organo-phosphorus and pyrethroid,

b) one or more surfactant,

c) one or more stabilizer,

d) an aqueous medium,

e) optionally one or more green oil or auxiliary agent,

wherein the stabilizer is selected from the group comprising of urea or its derivatives, triethanolamine, cocoamine, hexamine, tallowamine, epoxidized plant oil, p-anisaldehyde or a combination thereof.

In a further aspect, the present invention relates to an emulsion composition comprising:

a) active ingredient profenofos or ethion or a combination thereof,

b) one or more surfactant,

c) one or more stabilizer,

d) an aqueous medium,

e) optionally one or more green oil or auxiliary agent,

wherein the stabilizer is selected from the group comprising of urea or its derivatives, triethanolamine, cocoamine, hexamine, tallowamine, epoxidized plant oil, p-anisaldehyde or a combination thereof.

In another aspect, the present invention relates to an emulsion composition comprising:

a) profenofos or ethion in combination with cypermethrin or its derivatives thereof,

b) one or more surfactant,

c) one or more stabilizer,

d) an aqueous medium,

e) optionally one or more green oil or auxiliary agent,

wherein the stabilizer is selected from the group comprising of urea or its derivatives, triethanolamine, cocoamine, hexamine, tallowamine, epoxidized plant oil, p-anisaldehyde or a combination thereof.

In an aspect of the present invention, the median particle size of the emulsified composition is about 0.1 pm to about 5 pm, preferably about 1 pm.

In a further aspect, the present invention relates to a process for preparing an emulsion composition comprising the steps of:

A. Preparation of an oil phase comprising the steps of:

a. addition of one or more organo-phosphorus active ingredient,

b. addition of one or more surfactant,

c. optionally one or more green oil to obtain the oil phase,

B. Preparation of an aqueous phase comprising the steps of:

I. addition of one or more surfactant in an aqueous medium,

II. addition of one or more stabilizer,

III. optionally one or more auxiliary agent,

C. mixing the oil phase into the aqueous phase or vice-versa to obtain the emulsion composition.

In a further aspect, the present invention relates to a process for preparing an emulsion composition comprising the steps of:

A. Preparation of an oil phase comprising the steps of:

a. addition of one or more active ingredient selected from organo-phosphorus and pyrethroid,

b. addition of one or more surfactant,

c. optionally one or more green oil to obtain the oil phase,

B. Preparation of an aqueous phase comprising the steps of:

I. addition of one or more surfactant in an aqueous medium,

II. addition of one or more stabilizer,

III. optionally one or more auxiliary agent,

C. mixing the oil phase into the aqueous phase or vice-versa to obtain the emulsion composition.

The above mentioned steps for preparing the emulsion composition may be modified by a person skilled in the art.

In a further aspect of the present invention, the emulsion composition comprises of an aqueous phase and an oil phase; the surfactant in both phases has different hydrophilic-lipophilic balance (HLB) value, wherein the surfactant in oil phase has HLB value between 4 and 12 and the surfactant in aqueous phase has balance has HLB value between 12 and 20.

The emulsion composition according to the present invention is used to control pests in crops such as, but not limited to, cotton, tea, tobacco, potatoes, soybean, maize, capsicum, rice and other vegetable crops and offers the following advantages:

• offers high storage stability.

• use of environmentally friendly solvents in the preparation of the formulation as compared to toluene and/or xylene, which adversely impact the environment as well as mammals including humans.

offers higher biological activity.

Accordingly, it is an objective and advantage of the present invention to provide an environmentally safe and effective emulsion composition of one or more organo-phosphorus active ingredient or its combination with pyrethroid active ingredient that is effective against pests of cotton, tobacco, tea and vegetable crops such as potatoes.

Another objective and advantage of the present invention is to provide an emulsion composition that shows technical advancement compared to existing emulsion concentrate formulation of an organo-phosphorus or its combination with pyrethroid active ingredient.

Another objective and advantage of the present invention is to provide a composition which meets environmental and economic requirements imposed on modem-day insecticides which are continually increasing for example, about application rate, the formation of residues, low costs, and favorable preparation ability.

The above and other objectives will become more apparent in view of the description given below.

DETAILED DESCRIPTION OF THE INVENTION:

DEFINITIONS

It will be understood that the terminology used herein is to describe embodiments only, and is not intended to be limiting. As used in this specification, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, the reference to "a surfactant" includes one or more such surfactants.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although other methods and materials similar, or equivalent, to those described herein can be used in the practice of the present invention, the preferred materials and methods are described herein.

As used herein, the terms "comprises", "comprising", "includes", "including", or any other variation thereof, are intended to cover a non-exclusive inclusion, subject to any limitation explicitly indicated. For example, a composition or a method that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, or method.

As used herein, the term“composition” or "formulation" can be used interchangeably, unless stated otherwise, is meant to encompass, and are not limited to, compositions or formulations containing one or more organo-phosphorus active ingredient or its combination with pyrethroid active ingredient.

As used herein, the term“green oil” refers to the oils which are natural in origin or obtained from a plant source or cause less harm to the environment.

As used herein, the term "auxiliary agent" refers to inert substances which are commonly used as the diluent, to provide stability or to increase the activity profile of the formulation with or without having agrochemical activity or direct effect on the pests.

As used herein, the term“aqueous medium” refers to any polar solvent selected from water, ethanol, methanol, n-butanol, isopropanol, n-propanol, or formic acid, preferably the aqueous medium is water.

As used herein, the term“surfactant(s)” means a compound that, when dissolved in a liquid, reduces the surface tension of the liquid, which reduces the interfacial tension between two liquids or which reduces surface tension between a liquid and a solid. More typically the term“surfactant” is used herein to refer to a compound that, when dissolved in oil/water, reduces the surface tension of the oil/water.

As used herein, the term“stabilizer(s)” refers to a substance capable of imparting resistance against physical or chemical deterioration or deformulation.

As used herein, the term“defoamer agent(s)” refers to a chemical additive that reduces and hinders the formation of foam in the industrial process of liquids, semi-solids, or solids. The terms defoamer and anti-foaming agent are used interchangeably.

As used herein, the term“thickener(s)” refers to a polymeric material, which at a low concentration increases the viscosity of an aqueous solution and helps to stabilize the emulsion.

Unless otherwise specified, % refers to % weight; and % weight refers to % of the weight of respective component with respect to the total weight of the composition. For the present invention, the term“about” refers to +1% to 10% of a specified value.

As used herein, the term“profenofos” encompasses profenofos or its salt, derivatives or any other modified form of profenofos.

As used herein, the term“ethion” encompasses ethion or its salt, derivatives or any other modified form of ethion.

As used herein, the term“cypermethrin” encompasses cypermethrin or its salt, derivatives or any other modified form of cypermethrin like alpha-cypermethrin, beta-cypermethrin, deltamethrin, theta-cypermethrin or zeta-cypermethrin.

Accordingly, the present invention relates to an emulsion composition of one or more organo-phosphorus active ingredient (such as profenofos or ethion) or its combination with pyrethroid active ingredient (such as cypermethrin) to provide a fast-acting, safer-to-use, environmentally friendly formulation.

An emulsion is a conventional formulation in the field of the agrochemical formulations. The emulsion is pre-formed in the commercial product and is conventionally diluted with a carrier (usually water) when making up the spray mixture. They, therefore, differ from emulsifiable concentrates which comprise pesticides in an anhydrous formulation in organic solvents. Emulsifiable concentrates formulations form an emulsion only when making up the spray mixture. The disadvantage of emulsifiable concentrates formulation is the high content of organic solvents.

The emulsion composition according to the invention comprises of a continuous water phase and a dispersed oil phase. The mass median diameter of oil droplet size is usually in the range of about 0.1 to about 5 pm. The median particle size of the emulsified composition is about 0.1 pm to about 5 pm, preferably about 1 pm. The mass median diameter can be determined by particle-size measurement by laser diffraction, for example using a Malvern Mastersizer 2000.

In an embodiment of the present invention, the emulsion comprises of one or more organo-phosphorus active ingredient (such as profenofos, or ethion) or its composition with pyrethroid active ingredient (such as cypermethrin) as an active substance, dispersed in the water phase in the amount about 1% to 75% by weight, preferably about 2% to 65% by weight, and more preferably about 5% to 60% by weight.

In a preferred embodiment of the present invention, the emulsion composition according to the present invention further comprises of urea or its derivative as a stabilizer. The suitable content of urea or its derivative is 0.5% to 10% by weight.

The composition according to the present invention further comprises surfactant(s). Surfactant/ s) (an emulsifier, a dispersing agent, a wetting agent, a spreader, an adjuvant for penetration enhancement, rain fastness, soil leaching control etc.) are a nonionic, a cationic or an anionic surfactant or a combination of these surfactants. It is preferred to use one or more than one kind of surfactant e.g. the combination of a nonionic surfactant and an anionic surfactant; the combination of a nonionic surfactant and a cationic surfactant; or the combination of an anionic surfactant or a cationic surfactant.

Claims:

1. A method of stabilizing an agrochemical composition comprising of:

a) addition of one or more agrochemical active ingredient;

b) addition of one or more stabilizer;

c) optionally addition of one or more surfactant;

d) addition of an aqueous medium;

e) optionally addition of one or more green oil or auxiliary agent;

wherein the stabilizer is selected from the group comprising of urea or its derivatives, triethanolamine, cocoamine, hexamine, tallowamine, epoxidized plant oil, p-anisaldehyde or a combination thereof.

2. The method as claimed in claim 1, wherein the agrochemical active ingredient comprising of one or more organo-phosphorus active ingredient or its combination with one or more pyrethroid active ingredient.

3. The method as claimed in claim 2, wherein the organo-phosphorus active ingredient is selected from the group comprising of profenofos, ethion, chlorpyrifos, acephate, demeton-s- methyl, dichlorvos, dimethoate, fenitrothion, fention, malathion, monocrotophos, oxydemeton-methyl, parathion, parathion-methyl, phenoate, phorate, quinalphos, trizophos, chlorethoxyfos or a combination thereof.

4. The method as claimed in claim 2, wherein the pyrethroid selected from the group comprising of acrinathrin, allethrin , bioallethrin, barthrin, bifenthrin, kappa-bifenthrin, bioethanomethrin, brofenvalerate, brofluthrinate, bromethrin, butethrin, chlorempenthrin, cyclethrin, cycloprothrin, cyfluthrin, beta-cyfluthrin, cyhalothrin, gamma-cyhalothrin, lambda- cyhalothrin, cypermethrin, alpha-cypermethrin, beta-cypermethrin, theta-cypermethrin, zeta- cypermethrin, deltamethrin, dimefluthrin, dimethrin, empenthrin, chloroprallethrin, fenfluthrin, fenpirithrin, fenpropathrin, fenvalerate, esfenvalerate, flucythrinate, fluvahnate, tau-fluvalinate, furamethrin, furethrin, heptafluthrin, imiprothrin, japothrins, kadethrin, methothrin, metofluthrin, epsilon-metofluthrin, momfluorothrin, epsilon-momfluorothrin, pentmethrin, permethrin, biopermethrin, transpermethrin, phenothrin, prallethrin, profluthrin, proparthrin, pyresmethrin, renofluthrin, meperfluthrin, resmethrin, bioresmethrin, cismethrin, tefluthrin, kappa-tefluthrin, terallethrin, tetramethrin, tetramethylfluthrin, tralocythrin, tralomethrin, transfluthrin, valerate, preferably cypermethrin, alpha-cypermethrin, beta- cypermethrin, theta-cypermethrin or zeta-cypermethrin.

5. The method as claimed in claim 1, wherein the auxiliary agent is selected from the group comprising of co-solvent(s), anti-freezing agent(s), defoamer agent(s), thickener(s), preservative(s), pH adjuster(s), coloring agent(s) and/or odor masking agent(s).

6. The method as claimed in claim 1, wherein the surfactant is selected from the group comprising of nonionic surfactant, anionic surfactant or cationic surfactant.

7. The method as claimed in claim 6, wherein the non-ionic surfactant is selected from the group comprising of polyoxyethylene-polyoxyproylene block copolymer; the anionic surfactant is selected from the group comprising of sodium lauryl sulphate, calcium alkyl benzene sulphonate, sodium lauryl ether sulphate; cationic surfactant is selected from the group comprising of cationic hexadecyltrimethylammonium bromide, dodecylltrimethylammonium bromide, tetradecyltrimethylammonium bromide, or benzalkonium chloride.

8. The method as claimed in claim 6, wherein the surfactant is used alone or in combination thereof.

9. The method as claimed in claim 1, wherein the green oil is selected from the group comprising of paraffin oil, esters of fatty acids, glycerol fatty acids, plant oil, or epoxidized plant oil.

10. The method as claimed in claim 1, wherein the epoxidized plant oil is selected from the group comprising of the epoxidized form of castor oil, rapeseed oil, soya oil, cotton seed oil, canola oil, ricebran oil, palm oil, coconut oil, linseed oil, sunflower oil, peanut oil, thistle oil, or a combination thereof.

11. The method as claimed in claim 1, wherein the aqueous medium is water, ethanol, methanol, n-butanol, isopropanol, n-propanol, or formic acid, preferably water.

12. The method as claimed in claim 1, wherein the median particle size of the composition is about 0.1 pm to about 5 pm, preferably about 1 pm.

13. An emulsion composition comprising of:

a) one or more organo-phosphorus active ingredient,

b) one or more surfactant,

c) one or more stabilizer,

d) an aqueous medium,

e) optionally one or more green oil or auxiliary agent,

wherein the stabilizer is selected from the group comprising of urea or its derivatives, triethanolamine, cocoamine, hexamine, tallowamine, epoxidized plant oil, p-anisaldehyde or a combination thereof.

14. An emulsion composition comprising of:

a) one or more active ingredient in combination is selected from the group comprising of organo-phosphorus and pyrethroid,

b) one or more surfactant,

c) one or more stabilizer,

d) an aqueous medium,

e) optionally one or more green oil or auxiliary agent,

wherein the stabilizer is selected from the group comprising of urea or its derivatives, triethanolamine, cocoamine, hexamine, tallowamine, epoxidized plant oil, p-anisaldehyde or a combination thereof.

15. The emulsion composition as claimed in claim 13 or 14, wherein the organo-phosphorus active ingredient is selected from the group comprising of profenofos, ethion, chlorpyrifos, acephate, demeton-s-methyl, dichlorvos, dimethoate, fenitrothion, fention, malathion, monocrotophos, oxydemeton-methyl, parathion, parathion-methyl, phenoate, phorate, quinalphos, trizophos, chlorethoxyfos or a combination thereof.

16. The emulsion composition as claimed in claim 13, wherein one or more organo-phosphorus active ingredient may be combined with one or more pyrethroid active ingredient.

17. The emulsion composition as claimed in claim 14 or 16, wherein the pyrethroid selected from the group comprising of acrinathrin, allethrin , bioallethrin, barthrin, bifenthrin, kappa- bifenthrin, bioethanomethrin, brofenvalerate, brofluthrinate, bromethrin, butethrin, chlorempenthrin, cyclethrin, cycloprothrin, cyfluthrin, beta-cyfluthrin, cyhalothrin, gamma- cyhalothrin, lambda-cyhalothrin, cypermethrin, alpha-cypermethrin, beta-cypermethrin, theta- cypermethrin, zeta-cypermethrin, deltamethrin, dimefluthrin, dimethrin, empenthrin, chloroprallethrin, fenfluthrin, fenpirithrin, fenpropathrin, fenvalerate, esfenvalerate, flucythrinate, fluvalinate, tau-fluvalinate, furamethrin, furethrin, heptafluthrin, imiprothrin, japothrins, kadethrin, methothrin, metofluthrin, epsilon-metofluthrin, momfluorothrin, epsilon-momfluorothrin, pentmethrin, permethrin, biopermethrin, transpermethrin, phenothrin, prallethrin, profluthrin, proparthrin, pyresmethrin, renofluthrin, meperfluthrin, resmethrin, bioresmethrin, cismethrin, tefluthrin, kappa-tefluthrin, terallethrin, tetramethrin, tetramethylfluthrin, tralocythrin, tralomethrin, transfluthrin, valerate, preferably cypermethrin, alpha-cypermethrin, beta-cypermethrin, theta-cypermethrin or zeta-cypermethrin.

18. The emulsion composition as claimed in claim 13 or 14, wherein the organo-phosphorus active ingredient is profenofos, ethion, or a combination thereof.

19. The emulsion composition as claimed in claim 13 or 14, wherein the auxiliary agent is selected from the group comprising of co-solvent(s), anti-freezing agent(s), defoamer agent(s), thickener(s), preservative(s), pH adjuster(s), coloring agent(s) and/or odor masking agent(s).

20. The emulsion composition as claimed in claim 13 or 14, wherein the surfactant is selected from the group comprising of nonionic surfactant, anionic surfactant or cationic surfactant.

21. The emulsion composition as claimed in claim 20, wherein the non-ionic surfactant is selected from the group comprising of polyoxyethylene-polyoxyproylene block copolymer; the anionic surfactant is selected from the group comprising of sodium lauryl sulphate, calcium alkyl benzene sulphonate, sodium lauryl ether sulphate; cationic surfactant is selected from the group comprising of cationic hexadecyltrimethylammonium bromide, dodecylltrimethylammonium bromide, tetradecyltrimethylammonium bromide, or benzalkonium chloride.

22. The emulsion composition as claimed in claim 20, wherein the surfactant is used alone or in combination thereof.

23. The emulsion composition as claimed in claim 13 or 14, wherein the green oil is selected from the group comprising of paraffin oil, esters of fatty acids, glycerol fatty acids, plant oil, or epoxidized plant oil.

24. The emulsion composition as claimed in claim 13 or 14, wherein the epoxidized plant oil is selected from the group comprising of the epoxidized form of castor oil, rapeseed oil, soya oil, cotton seed oil, canola oil, ricebran oil, palm oil, coconut oil, linseed oil, sunflower oil, peanut oil, thistle oil, or a combination thereof.

25. The emulsion composition as claimed in claim 13 or 14, wherein the aqueous medium is water, ethanol, methanol, n-butanol, isopropanol, n-propanol, or formic acid, preferably water.

26. The emulsion composition as claimed in claim 13 or 14, wherein the median particle size of the emulsified composition is about 0.1 pm to about 5 pm, preferably about 1 pm.

27. A process for preparing the emulsion composition as claimed in claim 13, comprising the steps of:

A. Preparation of an oil phase comprising the steps of:

a. addition of one or more organo-phosphorus active ingredient,

b. addition of one or more surfactant,

c. optionally one or more green oil to obtain the oil phase,

B. Preparation of an aqueous phase comprising the steps of:

I. addition of one or more surfactant in an aqueous medium,

II. addition of one or more stabilizer,

III. optionally one or more auxiliary agent,

C. mixing the oil phase into the aqueous phase or vice-versa to obtain the emulsion composition.

28. A process for preparing the emulsion composition as claimed in claim 14, comprising the steps of:

A. Preparation of an oil phase comprising the steps of:

a. addition of one or more active ingredient in combination is selected from the group comprising of organo-phosphorus and pyrethroid,

b. addition of one or more surfactant,

c. optionally one or more green oil to obtain the oil phase,

B. Preparation of an aqueous phase comprising the steps of:

I. addition of one or more surfactant in an aqueous medium,

II. addition of one or more stabilizer,

III. optionally one or more auxiliary agent,

C. mixing the oil phase into the aqueous phase or vice-versa to obtain the emulsion composition.

29. The process as claimed in claim 27 or 28, wherein the surfactant in the oil phase having HLB value between 4 and 12.

30. The process as claimed in claim 27 or 28, wherein the surfactant in the aqueous phase having HLB value between 12 and 20.