Drug – bio-affecting and body treating compositions – Designated organic nonactive ingredient containing other... – Carboxylic acid ester
Reexamination Certificate
1999-07-27
2001-04-24
Carr, Deborah D (Department: 1621)
Drug, bio-affecting and body treating compositions
Designated organic nonactive ingredient containing other...
Carboxylic acid ester
C554S227000
Reexamination Certificate
active
06221919
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to the use of ethoxylated fatty acid esters as self-emulsifiable compounds, particularly useful for preparing phytosanitary treatment products or medicines for veterinary or human use.
It is known that an emulsion is a mixture of water and oil stabilised by surfactants.
The dispersion of oil in water (or water in oil) in the form of droplets sufficiently fine for obtaining a stable emulsion necessitates bringing about energy which is often considerable.
Furthermore, any oily preparation is called self-emulsifiable which is capable of forming a stable emulsion with an aqueous phase, practically without bringing about energy, by dispersion in the aqueous phase by slow mechanical stirring for example.
Self-emulsifiable compositions are particularly appreciated each time that mixtures with an aqueous phase, generally water, must be prepared without the need for efficient means of stirring.
Thus, it is notably a matter of:
within the context of domestic uses, e. g. for the preparation of household cleaning materials or gardening products;
within the context of agricultural uses, e. g. for the preparation of phytosanitary products intended for storage in tanks or other containers;
in the pharmaceutical field, e. g. for the preparation of extemporaneously made medicines.
Self-emulsifiable preparations have been described for a long time in the state of the art, especially in the agrochemical field.
These preparations are generally constituted of mineral oils or petroleum fractions to which not very harmful surfactants such as ethoxylated alkyl phenols in particular have been added.
Such preparations are however weakly biodegradable and therefore represent a potential danger to the environment, which has limited the development of them over the last years.
Recently, research has been orientated towards substitute products for petroleum oils and the use has been recommended to this end of biodegradable oils such as triglycerides or methyl esters of fatty acids in particular.
However, these oils are much more difficult to emulsify than mineral oils.
Furthermore, it has also been envisaged to replace ethoxylated alkyl phenols by biodegradable surfactants, but this has proved to be extremely difficult for cost and efficiency reasons.
SUMMARY OF THE INVENTION
Within this context, the aim of the present invention is to solve the technical problem which consists in providing a novel self-emulsifiable composition which is particularly useful for preparing phytosanitary treatment products or medicines for veterinary or human use, whose implementation is easy and which has a sufficient biodegradable character to fulfil the concerns of respect of the environment.
DETAILED DESCRIPTION OF THE INVENTION
It has been discovered, and this constitutes the basis of the present invention, that certain esters obtained by reaction between fatty acids, low molecular weight alcohols or polyols and ethylene oxide constitute self-emulsifiable components without the aid of any other surfactant, and are biodegradable and capable of dissolving active principles which are little or not soluble in water.
Thus, according to a first aspect, the present application aims at covering the use of ethoxylated fatty acid esters having one of the following formulae:
in which:
R
1
, R
3
, R
5
, R
6
, R
8
and R
10
represent a linear or branched, saturated or unsaturated hydrocarbon chain having from 5 to 30 carbon atoms;
R
2
, R
4
, R
7
and R
9
represent a linear or branched, saturated or unsaturated hydrocarbon chain having from 1 to 5 carbon atoms;
the total number of ethylene oxide molecules represented in the above-mentioned formulae I, II and III by k, l+m, n+p+q respectively being an integer such that the HLB value (hydrophilic-lipophilic balance) of said compounds be between about 4 and about 10, preferably between about 5 and about 9; and, preferably still, neighbouring 5.
as self-emulsifiable compounds which are particularly useful for preparing phytosanitary products or medicines for veterinary or human use.
Advantageously, it will be possible for the following products, as well as mixtures thereof, to be used in accordance with the present invention:
Ethoxylated fatty acid esters having the above-mentioned formula I in which R
1
is selected from palmitic, stearic, ricinoleic, oleic, linoleic and linolenic acid residues; R
2
represents a methyl radical and k is an integer between 1 and 5, preferably equal to 2;
Ethoxylated fatty acid esters having the above-mentioned formula III in which:
R
6
, R
8
and R
10
represent hydrocarbon chains corresponding to the fatty chains of a vegetable oil;
R
7
and R
9
represent a methylene group CH
2
;
n, p, q are integers such that their sum be between 3 and 30.
Ethoxylated fatty acid esters having the above-mentioned formula III in which:
R
6
, R
8
and R
10
represent hydrocarbon chains having from 16 to 22 carbon atoms corresponding to the fatty chains of rapeseed oil;
R
7
and R
9
represent a methylene group CH
2
;
n, p, q are integers such that their sum be between 3 and 30, and preferably equal to 20;
Ethoxylated fatty acid esters having the above-mentioned formula III in which:
R
6
, R
8
and R
10
represent hydrocarbon chains corresponding to the fatty chains of castor oil;
R
7
and R
9
represent a methylene radical CH
2
;
n, p and q represent integers such that their sum be between 5 and 7.
Within the context of the present description and claims, “hydrocarbon chain” is understood as meaning any chain constituted exclusively of carbon atoms and hydrogen atoms.
Alkyls, alkenyl or alkynyl chains constitute examples of such hydrocarbon chains.
The hydrophilic-lipophilic balance (also referred to as HLB) is defined by the following formula:
HLB
=
20
(
1
-
SI
AI
)
in which:
SI represents the saponification index of the product measured according to the NFT 60206 standard; and
AI represents the acid index of the acid used for the manufacture of the product measured according to the NFT 60204 standard.
The most interesting compounds within the context of the present invention are those which are liquid at ambient temperature.
The mixture of several products having the above-mentioned formulae I, II and III may be used advantageously for the preparation of specific self-emulsifiable compositions having particular density, viscosity or coagulation point characteristics.
The addition of biodegradable solvents which are miscible with these products, such as triglycerides, glycols, low molecular weight esters or ketones is also conceivable.
Esters or ketones having known solvent properties and which are generally obtained by condensation of a short-chain fatty acid (less than 10 carbon atoms) with an alcohol of less than 10 carbon atoms are referred to as low molecular weight esters or ketones.
Methyl isobutyl ketone, methyl ethyl ketone, ethyl acetate, amyl acetate, isoamyl acetate are examples thereof.
As examples of a preferred biodegradable solvent, propylene glycol, glycerine and glycerol triacetate can be mentioned.
It will be possible for these solvents to be present in the self-emulsifiable composition in amounts ranging from 0 to about 50% by weight compared to the total weight of the composition.
Ethoxylated fatty acid esters having a chemical structure very close to that of compounds of above-mentioned formulae I, II and III have been described in the literature, e. g. in the U.S. Pat. No. 2,678,935; U.S. Pat. No. 3,539,518; U.S. Pat. No. 4,022,808; GB 1,050,497 documents.
However, the prior documents contain no indication enabling the person skilled in the art to deduce that certain ethoxylated fatty acid esters having above-mentioned formulae I to III would constitute a self-emulsifiable phase.
The compounds used within the context of the present invention can be easily prepared by chemical methods similar to those described in the above-mentioned state of the art.
Generally, these compounds can be obtained:
either by an esterification of ethoxylated alcohols as described
Carr Deborah D
Dennison, Scheiner Schultz & Wakeman
SEPPIC
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