METHOD AND PROCEDURE FOR OBTAINING NATURAL PYRETHRIN MICROBIOCAPSULES WITH HIGH STABILITY

Abstract

The present invention describes a procedure for obtaining microbiocapsules of one or more pyrethrins as active substance, and is framed in the field of biopesticide production technique. Natural pyrethrin is a broad spectrum insecticide extracted from the flowers of the plant of the genus Chrysasnthemun and is easily decomposed by air and light. The present invention increases the stability of pyrethrins, being effective for a longer time than other solutions of the state of the art. The method and procedure comprises the following steps; a first oil phase, a second phase of mixture emulsion and a third encapsulation phase. The result is the obtaining of pyrethrin microbiocapsules with a size between 0.5 to 5 microns, with greater stability. The process does not reduce the insecticidal capacity of pyrethrins.

15

Claims

1. A procedure for obtaining pyrethrin microbiocapsules that comprises several steps: (1) Oily phase, consisting of a solution of one or more pyrethrin(s) as active substance with a concentration between (48% -80%), in one or more vegetable oil(s) in a 1:20 ratio; (2) emulsifying phase wherein an emulsifying agent is added; (3) phase for obtaining microbiocapsule s, wherein by means of a controlled mixing process, 4-25% w/v pyrethrin microbiocapsules are obtained.

2. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (1), the animal or vegetable oils are selected from the group consisting of sunflower, corn, soy, avocado, jojoba, pumpkin, grape seed, sesame, hazelnut, fish oils, glycerol tricaprocaprylate, or the vegetable or animal oils of the formula R.sub.9 000R.sub.10 in which R.sub.9 represents the moiety of a higher fatty acid comprising 7 to 29 atoms carbon and R.sub.10 represents a straight or branched hydrocarbon chain containing from 3 to 30 carbon atoms in particular alkyl or alkenyl.

3. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (1), wherein stirring between 60-150RPM is carried out.

4. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (1), the temperature is 20 to 40° C. 25

5. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (1), a solvent agent such as fatty acids and their derivatives, can be added.

6. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (1), a solvent agent such as lower alcohols, can be added.

7. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (1), a solvent agent such as natural or synthetic essential oils, can be added.

8. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (1), a solvent agent can be added that may be a mixture of claims 5, 6 and/or 7

9. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (2), a non-ionic emulsifying agent is added that appears in a proportion of 10 to 50% by weight of the composition with respect to the total weight of the composition.

10. In claim 9 the non-ionic emulsifying agent that is added is of the amphoteric or ampholytic type.

11. In claim 9 the non-ionic emulsifying agent that is added is of the anionic type.

12. In claim 9 the non-ionic emulsifying agent that is added is of the cationic type.

13. In claim 9 a second relatively hydrophobic emulsifying agent may be added in combination with a relatively hydrophilic agent.

14. In claim 13 the emulsifying agent is anionic in combination with a non-ionic agent.

15. In claim 13, the emulsifying agent is present in the composition, generally, in a proportion that can range from 10 to 50% by weight.

16. In claim 9, a co-formulating agent can further be added.

17. In claim 16 the co-formulating agent can be an antioxidant.

18. In claim 16 the co-formulating agent can be an acidulant.

19. In claim 16 the co-formulating agent can be a anti-foaming agent.

20. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (2), the temperature is between 10 ° -45 ° C.

21. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (3), a stirring of 60-300 RPM between 1 to 36 hours is carried out.

22. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (3), it is produced at a density between 0.910 g/cm.sup.3 and 0.980 g/cm.sup.3.

23. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (3), it is carried out at a pH between 5-10.

24. A procedure for obtaining pyrethrin microbiocapsules according to claim 1, characterized in that in phase (3), microbiocapsules of a size between 0.5μ and 5μ are produced.

25. The use of the encapsulated product resulting from the procedure according to claim 1, for the control of pests.

26. The use according to claim 25, wherein it is an insecticide.

27. The use according to claim 26, wherein it is a pyrethroid

28. The use according to claim 25, with an optimal efficacy durability of at least 2 years.

29. Use according to claim 25 wherein the emulsifier added in phase (2) is a cationic emulsifying agent that increases the insecticidal capacity .

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] To complement the description that is being made and in order to help a better understanding of the features of the invention, a set of drawings is attached as an integral part of said description, wherein with an illustrative and non-limiting nature, the following has been represented:

[0031] FIG. 1—Shows a chromatographic profile of the resulting composition under normal conditions and 14 days later in the same compound applying the MT 46.3 method.

[0032] FIG. 2—Shows a photograph of pyrethrin microbiocapsules wherein an epifluorescence microscope (Axioplan, ZEISS) is observed. A sample drop is placed on a slide (20x40x0.25mm) with a 20x objective.

[0033] FIG. 3—Shows a photograph of pyrethrin microbiocapsules wherein their size and monodispersity are indicated:

[0034] 1. Length 5.14 μm

[0035] 2. Length 4.42 μm

[0036] 3. Length 5.48 μm

[0037] 4. Length 5.14 μm

PREFERRED EMBODIMENT OF THE INVENTION

[0038] The invention will be illustrated below by means of tests carried out by the inventors, which show the effectiveness of the procedure of the invention:

[0039] Example 1 73g of a refined extract of chrysanthemum EDEOIL P60® were mixed as a source of pyrethrins 60% (w/w); Pyrethrin I, Cinerin I, Jasmoline I, Pyrethrin II, Cinerin II and Jasmoline II, the ratio between Pyrethrin I and Pyrethrin II was 1.85, with 557g of soybean oil with 50% linoleic acid and 25% in oleic acid, also containing lauric, myristic, palmitic, stearic and linolenic acid, stirring was carried out at 60rpm in HI 180x-2® at a temperature of 25° C. and 1g of extract rich in tocopherol E306 was added, stirring was continued for 20 minutes, then without stopping stirring, 158g of 99.5% propylene glycol and 185g of 97% polysorbate 80 Sorbilene® were added. Then 15g of D-limonene of 94% concentration (bitter orange) and 8g of vegetable glycerin E-422 were added, acting as a co-formulating agent, improving the tense activity of the formulation. It was stirred at 120 rpm for about 2 hours and the appearance of the microbiocapsules was observed (FIG. 2), then the microcapsules and their shapes were measured according to (FIG. 3).

[0040] Example 2

[0041] To determine the stability of the product, obtained by the process of the present invention as described in example 1, the method MT 46.3 (J. Zhang et al. J. of Chromatography A. 1218 (2011) 6621-6629 Dean was used Ban et al. Afr. J. of Biotechnology Vol. 9 (18), pp. 2702-2708, May 3, 2010) by means of heat stimulation to age the formulations and simulate the packaged and stored product (FIG. 1). Formulations that passed the test were considered viable for at least 2 years.

TABLE-US-00001 TABLE I Storage stability at 54° C. Assay 0 day 7 days 14 days Physical status Homogeneous Homogeneous Homogeneous (Method EPA OPPTS liquid liquid liquid 830.6303) Color Transparent Transparent Transparent (Method EPA OPPTS yellow yellow yellow 830.6302) Odor Typical Typical Typical (Method EPA OPPTS 830.6304) pH 1/100 (20° C.) 4.66 4.61 4.57 (Method CIPAC MT 75.3) Density (25° C.) 1.0390 g/ml 1.0392 g/ml 1.0386 g/ml (Method EPA OPPTS 830.7300) Acidity (% H2SO4)  0.063  0.065  0.068 (Method CIPAC MT 191) Wettability <10 sec. <10 sec. <10 sec. (Method CIPAC MT 53.3) Suspensibility 96.8  96.2  95.8  (Method CIPAC MT 184) Foam persistence <2 ml <2 ml <2 ml (ml in 1 minute) (Method CIPAC MT 47) Chemical composition: 4.48% w/v 4.48% w/v 4.48% w/v pyrethrins (Method HPLC-DAD)