FR2686511A1 - Pharmaceutical composition containing combinations of vanadium and/or niobium with amino acids or amino acid derivatives - Google Patents

Abstract

The invention relates to a pharmaceutical composition. This composition contains as active principle the combination of one mol of derivative of vanadium or of niobium with an oxidation number of 4 or 5, or of a mixture of derivatives of vanadium and of niobium in which the niobium and/or vanadium have an oxidation number of 4 or 5, with 1 to 100 mol of sulphur-containing L or D amino acid containing a natural amino acid side chain, or of a derivative of such an amino acid, this derivative being an alkali metal salt, a hydrochloride, a hydroxamate or a derivative containing at least one amide, ester or secondary or tertiary amine function resulting from the conversion of at least one of the acid and/or amine functions of the aforementioned amino acid, the aforementioned active principle being incorporated in a pharmaceutically acceptable excipient, vehicle or carrier. This composition is chiefly useful for the treatment or prevention of diabetes.

Description

Pharmaceutical composition containing associations of vanadium and / or niobium with amino acids or amino acid derivatives.

 The present invention relates to pharmaceutical compositions containing combinations of vanadium and / or niobium with amino acids or amino acid derivatives.

The synthesis of derivatives or complexes of vanadium and niobium is well known: for example it can be done according to the methods listed by Léopold Gmelins, and described in the collection Handbuch der anorganischen Chemie, Vanadium (System
Nummer 48), Verbindungen, Verlag Chemie-GMBH, Weinheim / Bergstrasse, in particular Teil B Leiferung 2, 1967, at pages 688-819 for organic complexes (pages 719-789 for complexes of V4, pages 790- 819 for V5 complexes) and in Handbuch der anorganischen Chemie, 8 Auflage, Niobium (System Nummer 49), Teil
B4, Verbindungen, Verlag Chemie-GMBH, Weinheim / Bergstrasse, 1973, in particular at pages 334-472 for organic complexes of niobium.

 A bibliographic review with 198 references on "The Bioinorganic Chemistry of Vanadium" was recently carried out by Dieter Rehder, (Angew. Chem. Int. Ed. Engl. 1991, 30, 148-167).

 It is known, and this emerges very particularly from the above publication, that the vanadium derivatives in aqueous solution exist in the form of several equilibrium species. Thus, vanadate, where vanadium is at oxidation state 5, depending on the pH and the concentration, can be in several monomeric forms (polycoordinated with solvent or Ligands), or polymeric, with one or more charges .

Thus, with hydroxylated derivatives of the HO-R form, vanadate spontaneously forms mono-, di- and tri-esters (CR0) VO (OH))
x 3-x which coexist in equilibrium. The coordination geometry is also very diverse, the degree of coordination generally ranging from 4 to 7 (sometimes 8) and the same ligand being able to coordinate the metal in an axial or equatorial position and giving rise to tetragonal pyramids, trigonal bipyramids, pentagonal or octahedral, etc.

The same is true for vanadyle, in which vanadium is in oxidation state 4, as shown in particular by J. Costa Pessoa et al., Polyhedron, 1988, 7, 1245-1262 and
Polyhedron, 1989, 8, 1173-1199, depending on the pH and the concentration if we note LH an amino acid like serine (alanine, threonine, etc.) and M the metal (VO in this case), it can one or more of the following species coexist: MLH, ML, MLH2, 3 ML2H2, ML2H, ML2, ML2H-1 'ML2H-2t M2L2H, M2L2H3, etc., as well as some hydrolysis or hydration products.

 Furthermore, it appears from the bibliographical study cited above that several studies have been devoted to the interaction of vanadium with amino acids or with small peptides or proteins (cf. the references cited therein, such as BR Nechay, Archives of Biochemistry and Biophysics, 1986, 251, 128-138). Complexes with cysteine esters have been described and patented. The complexes of vanadate with the ethyl ester of N-acetyl tyrosine were studied by NMR (A.S. Tracey and M.J. Gresser, Proc. Natl. Acad. Sci. USA, 1986, 83, 609-613).

Similarly, J. Costa Pessoa et al. have studied in physicochemistry the complexes of vanadyl with amino acids such as serine, alanine, threonine (Polyhedron, 1988, 7, 1245-1262 and
Polyhedron, 1989, 8, 1173-1199).

Circulating proteins such as albumin and ferredoxins are known to complex vanadium, as well as glutathione (natural tripeptide) complex vanadate and vanadyle. In Inorg. Chem. 1988, 27, 4312-4316, Dieter Rehder describes the complexation of vanadate by dipeptides based on gly, glu, pro, asp, ser, or tyr, and tripeptides in reference 12 of
B. Galeffi and AS Tracey, Inorg. Chem. 1989, 28, 1726-1734 (cf.

ref. 28 also), cf. also L.J. Theriot et al., J. Inorg.

Nucl. Chem. 1969, 31, 2841 and L. Casella et al. Inorganica chemica
Acta, 1988, 144, 89-97.

Complexes of cysteine with vanadium 4 have been described in the literature, for example the synthesis of complexes of the methyl or ethyl ester of cysteine with vanadyl (H. Sakurai et al., Inorganica Chimica Acta, 1988, 151 , 85-86 H Sakurai et al., Inorganica Chimica Acta, 1980, 46, L119-L120
MD Sifri et al., Inorganica Chimica Acta, 1988, 142, 229-234).

 Much work has been done on the activity of vanadium in the treatment of hyperglycemia. These are mainly scientific literature documents which deal only with mineral derivatives of vanadium.

In the literature since 1985, numerous studies describe the hypoglycemic effects of mineral derivatives of vanadate (+5) or vanadyle (+4) ions. An excellent bibliographical update can be found in the Doctoral Thesis in Pharmacy of
Jean-Jacques MONGOLD, September 1991, University of Montpellier I,
France.

 European patent EP-O 264 278 describes compositions with insulin-mimetic activity containing vanadates and mineral peroxovanadates.

 Furthermore, the applicant has described in its international applications WO 91/07406 and WO 91/13892 as well as in its French application not yet published and filed on May 21, 1991 under the number 91 06 174 organo-metallic complexes of transition metals porphyrinic structure useful in particular in the treatment of hyperglycemia.

 European patent EP-O 305 264 describes organomineral vanadyl compounds obtained from C6-C10 esters of cysteine. For the compounds described in this document, the hypoglycemic dose is 4.3 mg of vanadium / kg and the duration of action is approximately 6 h.

 Japanese patent JP 2 292 217 describes an antidiabetic activity for 7 vanadyle-dioxo complexes (tartrate, gluconate, malonate, oxalate, lactate, salycilate and acetyl-acetonate), as well as for 2 vanadyle-monoamino-monothio complexes: the l complex 'methyl ester of cysteine with vanadyl and that of 2-amino-ethane-thiol. For the complex of the methyl ester of cysteine with vanadyl, a lowering of the glycemia is described from 377 mg / dl for the controls to 318 mg / dl, for a dose of 3 mg of vanadium / kg and to 258 mg / dl for a dose of 10 mg vanadium / kg.

 The Applicants have now found that complexes resulting from the reaction of vanadium derivatives at degree of oxidation 4 or 5 with non-sulfur amino acids or derivatives of non-sulfur amino acids were more active for the treatment of diabetes than the others derivatives of this metal known for their anti-diabetic activity. The comparison was carried out on the one hand with mineral derivatives, vanadyl sulphate and sodium orthovanadate in particular, and with the complexes derived from cysteine and, this, for equivalent doses of metal.

The Applicant has thus demonstrated an effect of increasing the bioavailability of vanadium due to complexation by non-sulfur amino acids or derivatives of non-sulfur amino acids
It also demonstrated that a comparable effect could be obtained by complexing niobium at a degree of oxidation 4 or 5 with non-sulfur amino acids or derivatives of non-sulfur amino acids.

 By "complex" is meant the reaction product of the metal derivative on the ligand consisting of the amino acid or its derivative.

It is in fact a mixture of complexes corresponding to the fixing by bonds with 1 and / or 2 electrons of a variable number of heteroatoms according to the envisaged ligand and whose spatial arrangement around the metal and the degree of Metal coordination may vary.

 Complexes resulting from the reaction of a vanadium or niobium derivative at oxidation state 4 or 5 with an amino acid or an unsulfurized amino acid derivative have been found to be useful as active ingredient in medicaments for treatment diabetes and related diseases.

 The above complexes having the particularity of being formed very easily by contact either in solution or in suspension of the metallic derivative and of the organic derivative, the invention covers not only pharmaceutical compositions including said already formed complexes but also pharmaceutical compositions including mixture of the two types of constituents, the complexation of which will be carried out in vivo during the administration of the pharmaceutical composition.

 The term “association” denotes both the mixture of the two types of constituents and the product of the complexation reaction.

Thus, according to an essential characteristic, the present invention relates to pharmaceutical compositions containing as active principle the association of a mole of vanadium derivative, and / or of niobium with oxidation state 4 or 5 or of a mixture of derivatives vanadium and niobium where niobium and vanadium are at the oxidation state 4 or 5 with 1 to 100 moles of amino acid L or
D unsulfurized containing a side chain of natural amino acid or of a derivative of such an amino acid, said derivative being an alkali metal salt, a hydrochloride, a hydroxamate or a derivative containing at least one amide, ester or secondary or tertiary amine resulting from the transformation of at least one of the acid and / or amine functions of said amino acid, said active principle being incorporated in a pharmaceutically acceptable excipient or carrier.

 According to a variant of the invention, the ratio of the number of moles of amino acid or of amino acid derivative to the number of moles of the metal derivative will advantageously be between 2 and 5.

 The niobium or vanadium derivative will be at the oxidation state 4 or 5 and advantageously in the form of an oxide, a halide, an oxyhalide, a sulfate, an alkali metal metallate or d ammonium, an acetate, an acetylacetonate, said derivative can be in the form of a hydrate or a complex with a solvent.

 The amino acid is advantageously chosen from natural amino acids.

 According to an advantageous variant, the amino acid is chosen from natural amino acids having a side chain containing heteroatoms, with the exception of sulfur.

 Thus, the amino acid will advantageously be chosen from the group consisting of tryptophan, lysine, tyrosine, serine, threonine, arginine, aspartic acid, glutamine, asparagine, glutamate, aspartate. These amino acids can therefore coordinate or complex either a second metal ion or the same.

 Among the amino acids advantageously chosen, there is also proline.

 The amino acid derivatives useful according to the invention are the amino acid derivatives in the form of esters, amides or hydroxamates, that is to say derivatives of amino acids in which at least a carboxylic acid or free amine function has been transformed by reactions well known to those skilled in the art.

où Y est O ou -NH,
R est une chaîne latérale d'acide aminé,
R', R" et R"' sont indépendamment
- de l'hydrogène,
ou - une chaine hydrocarbonée aliphatique linéaire ou ramifiée contenant 1 à 30 atomes de carbone, de préférence 16 à 20 et contenant O à 6 insaturations et pouvant comporter des fonctions amine, alcool, thiol, phosphate, acide, éther, amide,
ou - une channe hydrocarbonée linéaire ou ramifiée contenant jusqu a 30 atomes de carbone et renfermant au moins un cycle aromatique ou hétéroaromatique,
R' pouvant également être un sucre ou un polyalcool.The amino acid derivatives used to form the complexes according to the invention are advantageously in one of the following forms

where Y is O or -NH,
R is an amino acid side chain,
R ', R "and R"' are independently
- hydrogen,
or - a linear or branched aliphatic hydrocarbon chain containing 1 to 30 carbon atoms, preferably 16 to 20 and containing O to 6 unsaturations and which may contain amine, alcohol, thiol, phosphate, acid, ether, amide functions,
or - a linear or branched hydrocarbon chain containing up to 30 carbon atoms and containing at least one aromatic or heteroaromatic ring,
R 'can also be a sugar or a polyalcohol.

 According to a variant of the invention, in the derivatives of formulas I, II or III above, R '= R "= R"' = H and the derivative is the amino acid itself.

 According to another variant, the amino acid derivative is a monoester. In formulas I, II or III, Y = O and R "= R" '= H.

 R ′ is then advantageously a C1-C30 alkyl, mono or polyunsaturated or arylalkyl group.

 As examples of such groups, mention may be made of methyl, ethyl, linoleyl, gamma-linolenyl, oleyl, phenyl, benzyl, ricinoleyl groups.

 According to another variant, the amino acid derivative is in the form of a monoamide and one of the groups R 'or R "or R"' is a C1 to C30 alkyl group, C1 to C30 alkenyl, arylalkyl or alkylaryl or an oleyl, linoleyl, gamma linlenyl, ricinoleyl group.

 According to another variant, the amino acid derivative is a sugar ester, mention will be made, for example, of the esters obtained by condensation of a glucose or a fructose on the acid function of an amino acid.

 According to another variant of the invention, the amino acid derivative is in the form of a hydroxamate.

According to another variant, the amino acid derivative is a secondary or tertiary amine. Among these secondary or tertiary amines, particular mention will be made of those for which
R "and / or R"'are linear or branched hydrocarbon chains containing 1 to 30 carbon atoms, in particular alkyl chains, or chains comprising from 1 to 6 unsaturations or alkylaryl chains.

 As examples of amino acid derivatives in the form of secondary or tertiary amine, there may be mentioned in particular for example N-oleylproline, N-benzylproline.

When the amino acid derivative carrying the desired branching or heteroatom functions is not commercially available, a person skilled in the art can prepare it by following the conventional methods of synthesis, protection and deprotection of functional groups. Such methods are in particular described in Peptide Chemistry, 1988, M. BODANSZKY, Berlin Spinger as well as in Protective Goups in Organic Synthesis, TW Greene,
Wiley Interscience 1980 and in Protective Goups in Organic
Chemistry, JFW McOmie, Plenum Press, 1973).

So
a) when it is desired to obtain a derivative with a branched hydrocarbon chain, it is possible for example
- on an acid function of the substrate, carry out the coupling of a branched alcohol (such as phytol, geraniol, farnesol, etc.), or of a primary or secondary amine by means of a coupling agent such as DCC , or, in the case of fatty alcohols, by esterification in a dehydrating medium (azeotropic removal of water),
- on an amine or alcohol function of the substrate, carry out the coupling of a branched acid by means of a coupling agent such as DCC, or by reaction with an acid anhydride,
- on an amine function (or an alcohol function transformed into an alcoholate) of the substrate, perform the coupling using a branched halogenated derivative (such as farnesyl or geranyl bromide, etc.),
b) when it is desired to obtain a derivative with a chain having ether or thioether functions, it is possible, for example, to esterify an acid function of the substrate, for example by hexa-ethylene glycol, or to alkylate an amine function of the substrate by a polythioether halogenated chain,
c) when it is desired to obtain a derivative with a chain having alcohol functions, it is possible, for example, to hydrate in alcohol or to oxidize in diol the unsaturation (s) of an unsaturated hydrocarbon chain of the substrate, for example the double bond of an oleylamine derivative by H30 or by K Mn 04.

It is also possible to couple along a) a chain containing, in addition to an alcohol, amine or free acid function, one or more OH functions protected, for example by methoxyethoxyethyl groups, then liberating the alcohol functions by
++ Zn ions
d) when it is desired to obtain a derivative with a chain having sulphate or phosphate functions, it is possible, for example, to transform an alcohol derivative obtained according to c) by means of a Cl
PO (OR) 2 or a Cl-SO2 (OR), R being, for example, a Me, Et,
Benzyl,
e) when it is desired to obtain a derivative with a chain having sulfonate or phosphonate functions, it is possible, for example, to transform an alcohol or amine function of the substrate by means of Cl-CH2-CH2PO (ONa) 2 or Cl- CH2-CH2SO2 (ONa),
f) when it is desired to obtain a derivative with a chain having acid functions, it is possible, for example, to couple along a) a chain containing, in addition to an alcohol, amine or free acid function, one or more COOH functions protected in the form tert-butyl ester, then release the COOH functions in an acid medium,
g) When it is desired to obtain a derivative with a chain having amine functions, it is possible, for example, to couple along a) a chain containing, in addition to an alcohol, amine or free acid function, one or more primary amine or amine functions secondary protected, for example, by t-butyloxycarbonyl (BOC) groups, then release the amine functions in an acid medium.

In the case of tertiary amines these do not need to be protected, for example, EDTA (by any of its acid functions) can be coupled to an amine function of the substrate, or else make an ester of tetrakis- (2-hydroxypropyl) -ethylene-diamine on an acid function of the substrate,
h) when it is desired to obtain a derivative with a chain having thiol functions, it is possible, for example, to couple along a) a chain containing, in addition to an alcohol, amine or free acid function, one or more thiol functions protected by Me3SiCH2CH2- groups, then release these SH functions by F ions
The metal is in the oxidation state 4 or 5.

 When the metal is vanadium, it is at degree of oxidation 4 or 5, preferably at degree of oxidation 4.

 When the metal is niobium, it is at degree of oxidation 4 or 5, preferably at degree of oxidation 5.

By way of example of metal derivatives which can be used according to the invention, mention will be made, by designating by (acac) an acetylacetonate group and by OAc an acetate group, the following derivatives VOS04, VCl4, VOCI2, VO (OAc) 2, VO (acac ) 2, VOICI3, V205, Na3VO4,
K3V04, NaV03, H4NV03, NbCl4, NbCl5, Nb205, as well as their hydrates (for example VOSO4, SH2O) or their complexes with a solvent, for example with water, THF (for example NbCl4, THF), ether , ethylene glycol, etc.

 An important advantage of the complexes useful according to the invention is that they are easily formed by simple contacting of amino acids or amino acid derivatives with the metal derivative.

 This reaction can be carried out either in solution in water or in a solvent.

 As solvent, mention may be made of hydroalcoholic mixtures, for example mixtures containing 100 to 70% of water for 0 to 30% of alcohol.

 The alcohol used in the constitution of the hydroalcoholic medium is advantageously chosen from linear or branched C1-C4 alcohols, advantageously ethyl alcohol.

 The reaction can also be carried out in suspension in an organic agent. By way of example, mention will be made of THF, DMF and dichloromethane.

 The organometallic complexes described above are used more particularly for the preparation of medicaments useful in the treatment or prevention of diseases such as diabetes, hypercholesterolemia, hypertriglyceremia, hyperlipidemia as well as complications associated with these pathologies .

 Examples of associated pathologies include arterial hypertension, arteriosclerosis, heart failure, peripheral ischemia or ocular pathologies progressing to blindness.

 The present invention therefore relates to pharmaceutical compositions including the complexes described above or the mixture of the two constituents not yet complexed but capable of complexing in the body.

 The pharmaceutical compositions containing the complexes or associations of the invention may be in different forms. The complexes of the invention will be incorporated into a pharmaceutically acceptable excipient, vehicle, or support.

 As pharmaceutically acceptable excipients, vehicles or supports, any excipient, vehicle or support well known to those skilled in the art can be used. Mention may be made, for example, and without limitation of lactose, corn starch, glucose, gum arabic, stearic acid or magnesium stearate, dextrin, mannitol, talc, an oil of natural origin rich in essential unsaturated fatty acids, etc. In particular, if necessary, other additives well known to those skilled in the art can be used, such as stabilizers, desiccants, binders, pH buffers, etc.

 An advantage of the complexes described above is that they can be used directly without prior purification other than the removal of the solvent, in particular when it is an organic solvent.

 The compositions of the invention can be administered in various ways, in particular by oral, permucosal (lingual, nasal, ocular) route. They can also be in injectable form and intended for subcutaneous, intramuscular or intravenous injection.

They can also be used in application
Local, for example in the form of patches.

 The organometallic associations advantageously represent from 5 to 80% by weight relative to the total weight of the pharmaceutical preparation, and are found incorporated in a pharmaceutically acceptable excipient, vehicle or support and compatible with the mode of administration envisaged.

 The pharmaceutical compositions according to the invention when they are intended for oral administration advantageously contain from 10 to 5000 nanomoles of metal derivative per dose.

 The compositions in the form of injectable formulations advantageously contain from 20 to 10,000 nanomoles of metal derivative per injectable dose of 1 to 10 ml.

 The compositions intended for local application, in particular in the form of a patch, advantageously contain from 0.1 to 100 micromoles of metal derivative per applicable dose.

 According to another aspect, the invention relates to the use of the complexes described above as active ingredient of a medicament useful for the treatment or prevention of diabetes and associated diseases.

 The following examples are given purely by way of illustration and in no way limit the invention. They demonstrate the ease of preparation of the complexes, their use for preparing pharmaceutical compositions and the effectiveness of the active ingredient.

Example 1
Preparation of a proline complex with vanadium 4
5 millimoles of vanadyl sulfate pentahydrate (1.265 g) are dissolved in 10 ml of distilled water, then 10 millimoles of L-proline (1.151 g) dissolved in 10 ml of distilled water are added. The blue solution obtained is evaporated to dryness under vacuum (water pump) while heating to 650C. The gray-black solid obtained has a melting point above 2000C.

Example 2
Preparation of a proline salt with vanadium 4
10 millimoles of L-proline (1.151 g) are dissolved in 10 ml of distilled water, then 10 millimoles of a 1N sodium hydroxide solution are added. To the sodium salt of proline thus obtained, 5 millimoles of vanadyl sulfate pentahydrate (1.265 g) dissolved in 10 ml of distilled water are added. There is a very rapid color change towards dark gray-navy blue. The products are then isolated by evaporation of the solvents to dryness.

Example 3
Preparation of a proline complex with vanadium 5
5 millimoles of sodium orthovanadate (0.919 g) are dissolved in 20 ml of distilled water, then 10 millimoles of L-proline (1.151 g) dissolved in 10 ml of distilled water are added. NMR analysis of vanadium 51 of this solution shows the existence of only two species, a majority of which. The colorless solution obtained is tested as it is after dilution.

Example 4
Preparation of a proline complex with vanadium 5:
2.5 millimoles of vanadium oxide (V205) are dissolved in 20 ml of distilled water to which 10 millimoles of sodium hydroxide are added, the solution becomes light yellow, then 10 millimoles of L-proline (1.151 9) are added. The solution obtained is very obscure.

NMR analysis of vanadium 51 of this solution shows the existence of 4 species. The solution left in the open air for several days leads to a blue-black product which precipitates slowly. It is isolated by filtration.

Example 5
Preparation of a proline complex with peroxovanadate
2.5 millimoles of vanadium oxide (V2O5) are dissolved in 2 equivalents of hydrogen peroxide at 30% by mass, then 10 millimoles of L-proline (1.151 g) are added. The solution obtained is red, with an orange foam on top. After 24 hours of rest at
o 8 C, the solution turns green.

Example 6
Preparation of a histidine complex with vanadium 4
10 millimoles of histidine (1.551 g) are dissolved in 15 ml of distilled water, then 5 millimoles of vanadyl sulfate pentahydrate (1.265 g) dissolved in 5 ml of distilled water are added. The solu
o blue obtained is evaporated to dryness by heating to 50 C under vacuum. The solid obtained is gray-blue.

Example 7
Preparation of an ornithine complex with vanadium 4
10 millimoles of ornithine hydrochloride (1.686 g) are dissolved in 15 ml of distilled water. The addition of 10.25 millimoles of K2C03 makes it possible to slightly basify the solution in which nitrogen is bubbled to remove the dissolved oxygen, then under nitrogen, 5 millimoles of vanadyl sulfate pentahydrate (1.265 g) dissolved in 5 ml of distilled and degassed water. Carbon dioxide evolution ensues. The solution
o obtained is evaporated to dryness by heating to 55 ° C. under vacuum.

Example 8
Preparation of an arginine complex with vanadium 4
10 millimoles of vanadyl pentahydrate sulfate (2.53 g) are dissolved in 20 ml of distilled water, then 10 millimoles of arginine (1.742 g) are added. The solution obtained is evaporated to dryness while heating to 6O0C under vacuum.

Example 9
Preparation of a complex of an arginine derivative (arginine hydroxamate) with vanadium 4
10 millimoles of vanadyl pentahydrate sulfate (2.53 g) are dissolved in 20 ml of distilled water, then 10 millimoles of arginine hydroxamate are added. The solution obtained is evaporated to dryness while heating under vacuum to 550C.

Example 10
Preparation of a complex of a lysine derivative (lysine benzylester) with vanadium 4
10 millimoles of lysine benzyl ester hydrochloride are dissolved in 40 ml of distilled and degassed water, then neutralized by the addition of 10.25 millimoles of K2CO3 while bubbling nitrogen through. Then, under nitrogen, 5 millimoles of vanadyl sulfate pentahydrate (1.265 g) dissolved in 5 ml of distilled and degassed water are added. Carbon dioxide evolution ensues. The solution obtained is evaporated to dryness while heating to
o 70 C under vacuum.

Example 11
Preparation of a proline complex with niobium 5:
In an anhydrous THF solution and under nitrogen, 25 millimoles of L-proline (2.875 g) are suspended, then 5 millimoles of NbCl5 (1.35 g) are added all at once. The resulting yellow solution becomes darker and darker very quickly (orange, then red, then brown, then black with blue reflections) as the proline dissolves. Then, it discolors very quickly until it becomes very slightly yellow. A little methanol is added, then the solvents are evaporated in vacuo (water pump) while heating to 400C. The result is a very thin clear yellow film on the balloon, which is practically unstuck. To recover the product, it is dissolved in 50 ml of water and it is transferred to a bottle, where it solidifies into a kind of white gelatin. The product thus obtained is tested as it is after dilution, and suspended.

Example 12
Preparation of a proline salt with niobium 4
In an anhydrous THF solution and under nitrogen, 20 millimoles of L-proline (2.3 g) are suspended, then 5 millimoles of the complex of niobium chloride with the
THF or NbCl4: THF (1.895 g). The resulting red-ocher solution quickly becomes darker (brown-black with yellow-green reflections). Add a little methanol, then evaporate
o solvents under vacuum (water pump) by heating to 40 C. This results in a very hygroscopic gummy product.

Example 13
Preparation of a proline derivative (proline-oleylamide):
10 millimoles of N are dissolved in 25 ml of anhydrous DMF
Boc-proline, then 20 millimoles of oleylamine and 11 millimoles of DCC (dicyclohexylcarbodiimide) are added. After 16 h of reaction, all of the proline has been consumed, the DCU (dicyclohexylurea) formed is filtered through a sinter, and the DMF is evaporated in vacuo of a vane pump. The amine function is then deprotected by stirring the product obtained in a 50/50 solution of dichloromethane / trifluoroacetic acid. The TFA salt of the product then precipitates in the form of a white solid which is filtered through a frit and rinsed with CH2Cl2, then with methanol. This salt is then neutralized with a solution of triethylamine in CH2Cl2 by vigorous stirring. The suspension obtained is then centrifuged, then filtered and rinsed twice with chloroform. The product, single spot in TLC (eluent 95 CH2Cl / S MeOH / 0, S AcOH) is then dried under vacuum in a heating desiccator. Yield 45%. A cisjurans mixture of proline C-oleylamide is obtained, the identity of the structure of which is confirmed by its 1 H NMR, IR and elementary (C, H, N) analyzes.

Preparation of the proline-oleylamide complex with vanadium 4
5 millimoles of the proline derivative are dissolved in 95% ethanol, and 5 milliliters of an aqueous solution containing 2.5 millimoles of VOS04.5H2O (0.632 g) are added thereto. The solvents are evaporated in vacuo at 35 ° C. Elementary analyzes (C,
H, N) and IR of the blue solid obtained are in accordance with what is expected.

Example 14
Preparation of a proline derivative (N-octadecyl proline)
In 250 ml of dichloromethane, 30 millimoles of 1-bromooctadecane (TO g) are dissolved, then 20 millimoles of proline (2.3 g) dissolved in 100 milliliters of methanol are added, as well as 40 millimoles of K2C03 (5.5 g ) which remain suspended. After 7 days of reaction at room temperature, all of the proline was consumed. The insolubles (K2C03 and
KBr). The product is suspended in 500 ml of heptane and
o placed at 6 C for 24 h. The filtrate containing the excess bromooctadecane is removed and the white deposit is recovered. The same operation is repeated twice. The product obtained, single spot in TLC (eluent 90 CH 2Cl2 / 8 MeOH / 2 AcOH) is then dried under vacuum in a heating dissector. Yield 70%. N-octadecyl proline is obtained, the identity of the structure of which is confirmed by its H, IR and elementary NMR (C, H, N) analyzes. This derivative forms stable emulsions between aqueous and organic phases. It is soluble in methanol.

Preparation of the N-octadecyl proline complex with vanadium 4
5 millimoles of the proline derivative are suspended with 50 ml of water, and 5 ml of an aqueous solution containing 2.5 millimoles of VOSO4.5H20 (0.632 g) are added thereto. The product is tested as it is after dilution and suspension in water.

Example 15
Preparation of a complex of a tyrosine derivative (thyrosine methyl ester) with vanadium 4
10 millimoles of the thyrosine methyl ester are dissolved in 30 ml of distilled water, then 5 millimoles of sodium meta vanadate (0.609 g) dissolved in 25 ml of distilled water are added. The solution obtained is evaporated to dryness while heating to 700C under vacuum. The solid obtained has a melting point above 2000C.

Example 16
Formulation in any pharmaceutically acceptable diluent or excipient a) Example of composition for oral administration
A metal complex prepared according to any one of Examples 1 to 15 is mixed in a mill, in an amount of 10 to 5000 nanomoles of metal (preferably from 20 to 250 nanomoles), with a sugar polymer, for example dextran or cellulose, with zinc stereate, in sufficient amounts to make a 100 milligram tablet, which is then coated with gum arabic and sorbitan monosterate. Advantageously, gastro-resistant capsules based on gelatin, titanium dioxide and cellulose ester can be prepared.

b) Example of composition for administration by injection
A metal complex prepared according to any one of Examples 1 to 15 and which is soluble in water, is dissolved in an amount of 20 to 10,000 nanomoles of metal (preferably from 50 to 500 nanomoles), in 1 to 10 milliliters of sterile deionized water (preferably 2 to 4 milliliters), then it is adjusted in pH and in mineral salts so as to be as close as possible to physiological saline (pH 7.4 and 9 g / l), by base acids, or mineral salts made up of elements found in the blood, preferably H +, HO, Na +, Cl.

c) Example of composition for local application:
A metal complex prepared according to any one of the preceding examples 1 to 15 is emulsified, micronized or suspended in an amount of 0.1 to 100 micromoles of metal (preferably from 1 to 20 micromoles), in a water emulsion, glycerol, mono-, diet triglycerides of fatty acids, and fatty alcohols.

Example 17
Determination of a hypoglycemic effect:
The injection of 60 mg / kg of streptozotocin intravenously into the rat causes, within 24 hours of the injection, the induction of stable, irreversible and insulin sensitive diabetes mellitus. Subsequent hyperglycemia can be reduced by the administration of substances with hypoglycaemic properties.

a) Protocol
The tests were carried out on male rats of the Wistar strain (6 per batch), coming from the breeding center of the
Faculty of Pharmacy of Montpellier.

 The animals are kept under observation for 4 days before the start of the tests. At the start of the test, the animals weigh on average 180 g. During the observation period, the animals, divided into cages of 3, receive food and drinking water ad libitum and are subjected to a temperature between 21 and 23 ° C. and to a day / dark cycle of 12 h.

 In all trials, diabetes was induced by injection of streptozotocin SIGMA in citrate buffer at pH 4.5.

 Animals weighing an average of 180 g are anesthetized with ether. An intravenous injection of streptozotocin is performed in the vein of the penis; a control glycemia is carried out 72 h after the administration of streptozotocin; only animals with a blood sugar level greater than or equal to 3 g / l (on average 3.8 g / l) are selected and subjected to treatment with the test substance.

The complexes tested were administered under the following injection conditions
- for vanadium derivatives, doses corresponding to 2 mg of metal were administered twice a day for the first two days and doses corresponding to 2 mg of metal were administered on the following 13 days,
- For niobium derivatives, doses corresponding to 120 micromoles of metal were administered the first two days and 60 micromoles the following 13 days.

 The glycemia control is carried out in the morning at 9 a.m., the time of the day when the glycemia of the diabetic control or treated rats, subjected to large variations during the day, is the highest. Diabetic rats receive only the excipient (physiological saline) and serve as diabetic controls; finally, "white control" rats of the same weight, which have not received an injection of streptozotocin are kept in order to compare the consumption of water and food.

b) Results
The daily glycemic control did not allow us to highlight the hypoglycemic effect during the first two days of treatment. A significant and significant drop in blood sugar compared to that of control rats appears from the following days and is maintained in most cases even after treatment is stopped. This is accompanied by an equally significant reduction in polyphagia and polydipsia, which they manifest from the first days. Food and water consumption cover values tending to approach those of non-diabetic control rats.

 The figures in the appendix show the water and food consumption and the evolution of the glycemia of the rats treated with the complexes of examples 1, 3, 6, 7, 11 and 14.

 Note that the values given in these figures are averages obtained for the whole of a lot.

 Since, in some cases, one or two animals in the batch are not corrected, these means are slightly higher than the corresponding parameters of healthy subjects.

 The results are represented, for each example, in the form of a bar diagram; the black bar corresponding to the results obtained with the diabetic controls and the hatched bar corresponding to the results obtained with the rats treated with the complexes according to the invention.

 FIGS. 1a, 1b and 1c respectively represent the variations in consumption of water, food and the variations in the blood sugar level over time for a batch of diabetic rats treated with the product of Example 1 in comparison with the results. obtained for a batch of untreated diabetic rats.

 FIGS. 2a, 2b and 2c respectively represent the variations in consumption of water, food and the variations in the blood sugar level over time for a batch of diabetic rats treated with the product of Example 3 in comparison with the results. obtained for a batch of untreated diabetic rats.

 FIGS. 3a, 3b and 3c respectively represent the variations in consumption of water, food and the variations in the blood sugar level over time for a batch of diabetic rats treated with the product of Example 6 in comparison with the results. obtained for a batch of untreated diabetic rats.

 FIGS. 4a, 4b and 4c respectively represent the variations in consumption of water, food and the variations in the blood sugar level over time for a batch of diabetic rats treated with the product of Example 7 in comparison with the results. obtained for a batch of untreated diabetic rats.

 FIGS. 5a, 5b and 5c respectively represent the variations in consumption of water, food and the variations in the blood sugar level over time for a batch of diabetic rats treated with the product of Example II in comparison with the results. obtained for a batch of untreated diabetic rats.

 FIGS. 6a, 6b and 6c respectively represent the variations in consumption of water, food and the variations in the blood sugar level over time for a batch of diabetic rats treated with the product of Example 14 in comparison with the results. obtained for a batch of untreated diabetic rats.

 Measuring cholesterol and triglyceride levels also shows a return to normal.

 Like humans, diabetic rats develop metabolic disorders (hypercholesterolemia, hyperlipidemia, hypertriglyceridemia ...) as well as pathologies such as hypertension, arteriosclerosis, heart failure, peripheral ischemia, or even eye pathologies progressing to blindness.

 It has been shown that in treated rats, which have become normoglycemic, the disorders and complications described above do not appear.

Example 18
The effect defined by a mixture containing the proline complex with vanadium 4 according to example 1 and the proline complex with niobium 5 according to example 11 is studied according to the protocol defined in example 17. We realized that we obtained a very clear anti-diabetic effect with lower doses of each of the complexes than those used in the previous example. We thus highlight a synergistic effect of the two types of complexes.

FIG. 7 gives the results obtained by treating diabetic rats by mixing the two complexes under the following conditions
- injection of doses corresponding to 20 micromoles of vanadium and 20 micromoles of niobium, the first two days,
- injection of doses corresponding to 10 micromoles of vanadium and 10 micromoles of niobium, the following 13 days.

 Figures 7a, 7b and 7c respectively giving the consumption of water, food and the blood sugar level of rats as a function of time clearly show the anti-diabetic effect of the mixture used.

Claims (18)

 1. Pharmaceutical composition, characterized in that it contains as active principle the association of one mole of vanadium derivative, of niobium to the degree of oxidation 4 or 5 or of a mixture of vanadium and niobium derivatives where niobium and / or vanadium are at the oxidation state 4 or 5 with 1 to 100 moles of amino acid L or D not sulfur containing a side chain of natural amino acid or a derivative of such an amino acid , said derivative being an alkali metal salt, a hydrochloride, a hydroxamate or a derivative containing at least one amide, ester or secondary or tertiary amine function resulting from the transformation of at least one of the acid and / or amine functions of said amino acid , said active ingredient being incorporated into a pharmaceutically acceptable vehicle or carrier excipient.  2. Pharmaceutical composition according to claim 1, characterized in that the ratio of the number of moles of amino acid or amino acid derivatives to the number of moles of metal derivative is between 2 and 5.  3. Pharmaceutical composition according to one of claims 1 or 2, characterized in that the derivative of vanadium or niobium in the oxidation state 4 or 5 is in the form of an oxide, a halide, a oxyhalide, a sulfate, an alkali metal or ammonium metallate, an acetate, an acetylacetonate, said derivative being able to be in the form of a hydrate or of a complex with a solvent.  4. Pharmaceutical composition according to one of claims 1 to 3, characterized in that the non-sulfur amino acid is a natural amino acid.  5. Pharmaceutical composition according to one of claims 1 to 4, characterized in that the amino acid comprises a side chain containing heteroatoms, with the exception of sulfur.  6. Pharmaceutical composition according to one of claims 1 to 4, characterized in that the amino acid belongs to the group of tryptophan, lysine, tyrosine, serine, threonine, arginine of l aspartic acid, glutamine, aspargine, glutamate, aspartate, and proline.  7. Pharmaceutical composition according to one of claims 1 to 6, characterized in that the amino acid or the amino acid derivative corresponds to one of the following formulas

 where Y is O or - NH  R is an amino acid side chain,  R ', R "and R"' are independently  - hydrogen,  or - a linear or branched aliphatic hydrocarbon chain containing 1 to 30 carbon atoms, preferably 16 to 20, and containing 0 to 6 unsaturations and which may contain amine, alcohol, thiol, phosphate, acid, ether, amide functions,  or - a linear or branched hydrocarbon chain containing up to 30 carbon atoms and containing at least one aromatic or heteroaromatic ring.  R 'can also be a sugar or a polyalcohol.  8. Composition according to claim 7, characterized in that the amino acid derivative is a monoester corresponding to one of formulas II or III in which:  R "= R" '= H  Y = O  R 'is an alkyl, alkenyl or alkylaryl group containing 1 to 30 carbon atoms.  9. Composition according to Claim 7, characterized in that the amino acid derivative is a monoamide and one of the groups R ', R "or R"' is an alkyl or alkenyl group in C1 to C30 linear or branched or an aralkyl or alkylaryl group or an oleyl or linoleyl, or y-linolenyl or ricinoleyl group.  10. Composition according to one of claims 1 to 7, characterized in that the amino acid derivative is a hydroxamate.  11. Composition according to claim 7, characterized in that the amino acid derivative is a secondary or tertiary amine corresponding to formula II or III in which R "and / or R" 'are linear or branched hydrocarbon chains comprising 1 with 30 carbon atoms, in particular alkyl chains, chains comprising 1 to 6 unsaturations, or alkylaryl chains.  12. Pharmaceutical composition according to one of claims 1 to 11, characterized in that said association is in the form of a mixture of complexes resulting from the reaction of said metal derivative with the amino acid or its derivative.  13. Pharmaceutical composition according to one of claims 1 to 12, characterized in that the metal derivative is a derivative of vanadium with the oxidation state 4.  14. Pharmaceutical composition according to claim 1 to 12, characterized in that the metal derivative is a niobium derivative at the oxidation state 5.  15. Pharmaceutical composition according to one of claims 1 to 14, characterized in that it is produced for an oral formulation and contains 10 to 5000 nanomoles of metal derivative per dose.  16. Pharmaceutical composition according to one of claims 1 to 14, characterized in that it is produced for an injectable formulation and contains 20 to 10,000 nanomoles of metal derivative per injectable dose of 1 to 10 ml.  17. Pharmaceutical composition according to one of claims 1 to 14, characterized in that it is formulated for local application in particular in a patch and contains 0.1 to 100 micromoles of metal derivative per applicable dose.  18. Use of mixtures resulting from the complexation of one mole of vanadium derivative, of niobium at oxidation state 4 or 5 or of a mixture of vanadium derivatives and niobium where niobium and / or vanadium are at oxidation state 4 or 5 with 1 to 100 moles of unsulfured amino acid L or D containing a side chain of natural amino acid or a derivative of such an amino acid, said derivative being an alkali metal salt , a hydrochloride, a hydroxamate or a derivative containing at least one secondary or tertiary amide, ester or amine function resulting from the transformation of at least one of the acid and / or amine functions of said amino acid, as active principle of a useful medicament for the treatment of diabetes and related diseases.