Organic compounds -- part of the class 532-570 series – Organic compounds – Silicon containing
Reexamination Certificate
1996-07-16
2001-01-09
Shaver, Paul F. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Silicon containing
C556S408000, C556S409000, C556S410000, C556S411000, C556S466000, C556S413000, C556S419000, C556S418000, C556S426000, C556S460000, C556S461000, C514S064000, C514S844000, C514S944000, C424S401000, C424S457000, C424S078030, C424S048000, C424S049000, C424S070100, C424S078040, C549S214000
Reexamination Certificate
active
06172250
ABSTRACT:
SUMMARY
Preparation process of a biologically active compound consisting in hydrolyzing a precursor with the formula
in which A, B, C, D and X indicate radicals different from OH, the A B, C, D bonds with the Si atom being covalent bonds and 2 or 3 of these bonds are hydrolysable. The hydrolysis is carried out in a solvent containing a small quantity of water in a proportion with regard to the solvent preferably included between 0.1% and 5%, and at least one of the compounds obtained from the silicon hydrolyzed bonds is a compound said stabilizing preventing the formation of polymers from silicon hydrolyzed bonds.
TECHNICAL FIELD
The present invention concerns biologically active silicon compounds and in particular a process for the preparation of biologically active silicon compounds in a concentrated form starting from hydrolysable precursors.
BACKGROUND ART
Silicon is a very common element in nature and is generally known under its natural inorganic forms such as silica and silicate, and also under the form of synthetic polymers, the silicones. These silicon-containing compounds are barely soluble or not at all soluble in aqueous medium which explains their weak incidence at the alive organisms level. The silicones, in particular, are characterized by a great inertia towards the biological medium and consequently present a high biocompatibility.
However, the silicon, even in minute quantities, plays an important biological role and must be considered as an essential element of life. It is especially necessary for a normal growth of numerous species. It has been demonstrated that silicon was intervening in the connective tissue structuration in interacting with the glycosaminoglycan and proteins. This is one of the constitutive elements of proteins-glycosaminoglycan complexes found in the extracellular matrix of these tissues. Silicon also interacts with the glycosaminoglycan in the cartilage tissue development. We also know that silicon plays an important role in the bone formation where it favours the mineralization process.
Besides, silicon can be considered as a collagen constituent and we think that it plays a major role in the reticulation process of collagen fibers. Silicon also intervenes at the hair texture level where it would especially contribute to increase the resistance of the hair fibre. Silicon is also involved in the cell metabolism and it would be especially favourable to the metabolic activity of osteoblasts.
Beyond the cross-linking power of silicon and its implication in the metabolic activity of some cells, it appears that a high silicon content, in the tissues, jointly with the glycosaminoglycan content is characteristic of healthy and metabolically active tissues. In the same way, numerous works have demonstrated the importance of silicon in the physiological cycle regulation of the hair.
Today's researches tend to reinforce the idea that silicon intervenes in numerous biological mechanisms. Recent works have even demonstrated that silicon plays a major role in the aluminum elimination by biological systems.
Works of the applicant have demonstrated that silicon compounds could constitute a form of assimilable silicon by the organism (as opposed to mineral silicon or to silicones) on condition that it possesses the characteristic of existing in aqueous solution under the form of soluble oligomers of low molecular weight. Furthermore, another necessary characteristic of the oligomers activity in aqueous solution is to present numerous Si—OH functions. So, it is evident that the biological properties of these bioavailable compounds are only observed if they form soluble oligomers in aqueous solution, which result from a chain of siloxane bonds Si—O—Si, rich in Si—OH functions.
Apart from the fact that the presence of Si-OH highly polar functions confers their water solubility to the oligomers, at the present time, we think that a part of the properties observed are conducted by the fact that the chemical species involved in most of the above mentioned biological mechanisms would be a form of soluble silicon, the silicic acid of Si(OH)
4
formula. This compound only exists at very low concentrations in water since it has a very strong tendency to polycondense to form silica.
Consequently we have researched more stable products similar to silicic acid, by chemically modifying the Si-OH functions. It quickly became obvious that these functions were essential for the biological activity. In other respects, we knew that a series of natural compounds, and among them, the tannins and the catecholamines were capable of forming a complex with the silicic acid and like this were capable of increasing its stability in solution. These complexes would be the way of transport for the silicic acid in the organism and it is under this form that the cell would introduce the silicon. Nevertheless, their stability is still too weak for the carrying out of a pharmacologically active product.
The applicant has perfected active analogues of these complexes. It concerns products resulting from the complexation between a complexing molecule and an active organo-silicon compound. The characteristic of these compounds is to possess several Si-OH functions like the silicic acid, but also one or two carbon-silicon bonds. Nevertheless, these analogues possessing researched biological properties, even if they are more stable than the silicic acid complexes, still they must be prepared under the form of diluted aqueous solutions, which silicon content cannot exceed 2 g/litre owing to the fact that with a higher concentration, we would favour the polycondensation.
SUMMARY OF THE INVENTION
This is why the main goal of the invention is to provide biologically active silicon-containing compounds not developing towards the formation of inactive polycondensed forms such as polysiloxane.
Another goal of the invention is to carry out a preparation process of biologically active silicon compounds under a concentrated form by hydrolysis of silicon containing precursors with the release of stabilizing products preventing the polycondensation of silicon compounds.
The subject of this invention is then a preparation process of a biologically active silicon compound consisting in hydrolyzing a precursor having the formula
in which
A, B, C, D and X indicate radicals different from OH, the links A, B, C, D with the Si atom being covalent bonds and 2 or 3 of these bonds are hydrolysable. The hydrolysis is carried out in a solvent containing a small water quantity and in a proportion with regard to the solvent preferably between 0.1% and 5%, and at least one of these compounds coming from the hydrolyzed bonds of silicon is a compound said stabilizing preventing the formation of polymers from the silicon hydrolyzed bonds.
DESCRIPTION OF THE INVENTION
All along the description, we shall call “silyl” the biologically active compound obtained from the invention process, keeping the word “precursor” to indicate the biologically inactive silicon compound, and which is hydrolysable according to the invention process.
Radicals which are hydrolysable are either hydrogen atoms or preferably radicals linked to Si by an oxygen atom, a nitrogen atom or by a sulphur atom. Therefore, they can be esters or alkoxy, aryloxy radicals such as phenoxy radicals or allyloxy or vinyloxy radicals, when the silicon atom is directly bond to an oxygen atom. These radicals can also be thioester or aryl or alkylthioether radicals, when the silicon is bound by a sulphur atom. The radicals can also be amines, mono or disubstituted by hydrocarbon chains substituted or not by one or several functional groups, aryl or alkylamide, when the silicon is bound to a nitrogen atom.
The radicals bound to Si and which are not hydrolysable can be hydrocarbon radicals, substituted or not by one or several functional groups, certain alkoxy radicals with a steric hindrance, the fluorocarbon radicals or even a fluorine atom.
In the second type of general formula, the radical X can be an hydrocarbon radical, substituted by one or several func
Franco Andre
Gueyne Jean
Nicolay Jean-Francois
Seguin Marie-Christine
EXSYMOL S.A.M.
Lydon James C.
Shaver Paul F.
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