Organic compounds -- part of the class 532-570 series – Organic compounds – Fatty compounds having an acid moiety which contains the...
Reexamination Certificate
2003-01-21
2004-12-07
Pryor, Alton N. (Department: 1616)
Organic compounds -- part of the class 532-570 series
Organic compounds
Fatty compounds having an acid moiety which contains the...
C554S124000, C554S174000, C560S001000, C560S129000
Reexamination Certificate
active
06828451
ABSTRACT:
Method for preparing a fatty substance ester and use thereof in pharmaceutics, cosmetics or food industry.
The present invention relates to a novel process for the preparation of an ester of fatty substance and of an alcohol chosen from the group consisting of sterols, stanols, 4-methylsterols and their hydrogenated homologs, triterpene alcohols and their hydrogenated homologs, and the mixtures of these, this ester being intended in particular for a pharmaceutical use, in particular a dermatological use, and for a cosmetic or food use.
Phytosterols (family of the phytohormones) and essential fatty acids are compounds with a high biological activity which are therefore advantageous [lacuna] the fields of pharmaceuticals, cosmetics and the human diet.
Phytosterols are compounds of terpene origin which constitute the major fraction of plant unsaponifiable materials, an example of which is &bgr;-sitosterol. Since the 50s, phytosterols have been known in particular for their hypocholesterolemic action (Ling & Jones (1995), Life Sciences, Vol. 57, No. 3, pp. 195-206). The hypothesized mechanism of action is as follows: phytosterols lead to a decrease in the blood cholesterol by competing with the latter for its dissolution within the micelles of the bile salts in the intestine. In addition, the sterols lead to a decrease in the blood cholesterol (LDL) and a slight increase in the synthesis and excretion of endogenous cholesterol.
In an analogous way, polyunsaturated fatty acids (PUFAs) play an essential role at the nutritional level. By way of example, linoleic acid is an essential compound to the body since the latter cannot synthesize it (Delplanque et al. (1999), Oléagineux Corps Gras Lipides [Oleaginous Lipid Fatty, Substances], Vol. 1, pp. 86-93). It is in fact the starting member of the metabolic series of the n-6 or &ohgr;-6 PUFAs, fatty acids which are vital to the body. This series of acids comprises in particular arachidonic acid (C20:4), which is at the basis of the synthesis of chemical mediators, such as eicosanoids, which control numerous functions of the body, in particular platelet aggregation, the renal function and the immune response. Mention may also be made, among essential fatty acids, of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), for their preventive role with respect to cardiovascular diseases and some cancers.
Finally, at the dermocosmetic level, sterols and essential fatty acids are also essential compounds. Sterols are known for their antiinflammatory and antierythematous properties, in addition to their soothing and restructuring action (Wachter, Salka, Magnet, Cosmetics & Toiletries, (1995), Vol. 110, pp. 72-80). Furthermore, by limiting transepidermal water losses, mono- and polyunsaturated fatty acids for their part have a moisturizing and nutritional action. Finally, sterols and PUFAs have an important role in the synthesis of the lipids of the epidermal cutaneous barrier.
With the aim of increasing the bioavailability of sterols, and of stanols, their saturated homologs, it is known in the prior art to increase the lipophilicity of these compounds by subjecting them to an esterification reaction with a fatty substance, in particular a fatty acid or a derivative of the latter, preferably in the presence of a catalyst.
Currently, sterols and stanols are esterified by a transesterification reaction in the presence of homogeneous basic catalysts, such as sodium methoxide. The presence of NaOMe necessitates additional stages in which the catalyst in destroyed, leading to the formation of salts which it is absolutely essential to destroy. All these latter operations represent a very high additional coat in the production of these esters of sterols and of stanols. Furthermore, the use of homogeneous catalysts can promote side reactions in which the compounds are decomposed, the effect of which may be to modify the final appearance of the product (color and/or smell).
Heterogeneous catalysis, in comparison with homogeneous catalysis, exhibits the advantage of employing catalysts which can be more easily separated from the reaction medium and of creating fewer problems of corrosion and of side reactions. Mention may thus be made of magnesium oxide, which, however, exhibits the disadvantage of causing dehydration side reactions and/or reactions in which unsaturated bonds are isomerized, which reactions are unacceptable, in particular in the case of products intended for food use.
It has now been found, entirely surprisingly and unexpectedly, that the use of a certain class of compounds makes it possible to obtain an excellent heterogeneous catalysis effect for the esterification reaction involving at least one fatty substance and at least one sterol and/or one stanol and/or one 4-methylsterol, or a hydrogenated homolog of the latter, and/or one triterpene alcohol, or a hydrogenated homolog of the latter. The fatty substance esters obtained by the process according to the invention are very particularly suitable for the sectors of pharmaceuticals, in particular dermatology, cosmetics and specialized food (functional foods, medicinal foods, cosmetic foods).
The present invention thus relates to a process for the preparation of a fatty substance ester, characterized in that at least one fatty substance is subjected to an esterification reaction with at least one alcohol compound chosen from the group consisting of sterols, stanols, 4-methylsterols and their hydrogenated homologs, triterpene alcohols and their hydrogenated homologs, and mixtures of these, in the presence of at least one solid catalyst chosen from the group consisting of oxides of lanthanide metals and mixtures of these oxides.
The term “solid catalyst” is understood to mean, according to the invention, a catalyst which is undissolved in the remainder of the liquid reaction medium and which can be recycled after use.
The term “lanthanide oxide” is understood to mean, according to the invention, an oxide chosen from the group consisting of lanthanum oxide, cerium oxides, praseodymium oxides, neodymium oxides, promethium oxides, samarium oxides, europium oxides, gadolinium oxides, terbium oxides, dysprosium oxides, holmium oxides, erbium oxides, thulium oxides, ytterbium oxides, lutenium oxides and mixtures of these oxides.
The solid catalyst is preferably chosen from the group consisting of lanthanum oxide La
2
O
3
, ceric oxide CeO
2
, praseodymium oxides PrO
2
, Pr
6
O
11
and Pr
2
O
3
, samarium oxide Sm
2
O
3
and mixtures of these oxides.
More particularly, the solid oxide is preferably lanthanum oxide La
2
O
3
.
The solid catalyst can be provided in particular in a solid form chosen from the group consisting of powders, grains (pellets), beads, extruded forms and mixtures of these.
Preferably, the solid catalyst is in the form of a powder having a mean particle size of in particular between 1 and approximately 1000 micrometers, more particularly between approximately 10 and approximately 500 micrometers and very particularly preferably between approximately 50 and approximately 100 micrometers.
The solid catalyst can be supported on an inert support, that is to say a support which is inert in the presence of the reactants and products of the esterification reaction, such as the porous or nonporous inert supports known to a person skilled in the art, for example alumina or silica.
The oxides of lanthanides used as catalysts in the process according to the invention can be prepared according to methods known to a person skilled in the art, including when a supported catalyst is involved. They are also commercially available, such as the “LSA” and “HSA” forms sold by Rhodia.
The weight of catalyst to be used in the process according to the invention can be determined by a person skilled in the art using his overall knowledge, in particular with regard to the esterification reaction.
In particular, the solid catalyst used in the process according to the invention is present in the reaction medium in a proportion of between approximately 0.01 and approximately
Barrault Joë
Boisseau Mickaël
Piccirilli Antoine
Pouilloux Yannick
Laboratoires Expanscience
Pryor Alton N.
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