ECOBIOLOGICAL TREATMENT OF SIDE EFFECTS OF RADIOTHERAPY

Abstract

The present invention concerns a three-dimensional bipolymeric matrix deploying biological and biomechanical activity, able to neutralize the various physiopathological parameters involved in the development and worsening of skin lesions and/or sores, combining: a first polymeric network comprising first colloids (Col-1) bonded non-covalently to an unsulfated crosslinked polysaccharide; and a second polymeric network comprising second colloids (Col-2) bonded covalently or non-covalently to a sulfated polysaccharide.

Claims

1. A three-dimensional bipolymeric matrix exhibiting biomechanical activity, capable of neutralizing the various physiopathological parameters involved in the development and aggravation of skin lesions and/or sores combining: a first polymeric network comprising first colloids (Col-1) non-covalently bonded to an unsulfated crosslinked polysaccharide; and a second crosslinked polymeric network comprising second colloids (Col-2) bonded covalently or non-covalently with a sulfated polysaccharide.

2. The matrix according to claim 1, wherein the Col-1 colloids are cerium dioxide colloids and the unsulfated polysaccharide is selected from the group consisting of alginate, hyaluronic acid, guar gum, xanthan gum, acacia gum, pullulan, dextran and mixtures thereof.

3. The matrix according to claim 1, wherein the Col-2 colloids are platinum colloids and the sulfated polysaccharide is selected from the group consisting of a compound whose INCI designation is aphanothece sacrum polysaccharide, glycosaminoglycans sulphates, glucans, fucans, fucoidans, carrageenans, ulvans, pentosan polysulfate and mixtures thereof.

4. The matrix according to claim 1, wherein the second colloids (Col-2) are non-covalently bonded to the sulfated polysaccharide.

5. A dressing to prevent and/or heal a skin sore comprising the matrix according to claim 1.

6. A method of preventing and/or healing a skin sore or radiodermatitis, said method comprising applying the matrix according to claim 1 to skin having thereon the skin sore or radiodermatitis.

7. The method according to claim 6, of preventing and/or healing a skin sore, wherein the skin sore is dry or exudative.

8. The method according to claim 6, of preventing and/or healing radiodermatitis, wherein the radiodermatitis is of dry to exudative grade.

9. A method of producing a three-dimensional bipolymeric matrix according to claim 1, wherein the matrix is obtained by mixing: a solution (A) comprising Col-1 colloids non-covalently bonded with an unsulfated polysaccharide, a source of divalent metals, and Col-2 colloids surface and covalently bonded with an agent capable of positively charging the colloid; and a solution (B) comprising an acidifier and a sulfated polysaccharide.

10. The method according to claim 9, wherein: Col-1 colloids are cerium dioxide colloids; the unsulfated polysaccharide is alginate; the source of bivalent metals is a calcium salt; Col-2 colloids are platinum colloids of zero oxidation state, surface and covalently bonded with an agent capable of positively charging the colloid; the acidifier is gluconolactone; and the sulfated polysaccharide is the compound corresponding to the INCI designation aphanothece sacrum polysaccharide.

11. The method according to claim 9, wherein the two solutions (A) and (B) are mixed in a proportion of 4/5 of solution (A) and 1/5 of solution (B).

12. A device for implementing the method according to claim 9, said device comprising the solution (A) and the solution (B).

13. The device according to claim 12, wherein the solution (A) and the solution (B) are packaged in a bottle, a sprayer, a syringe or as a single dose vial.

14. The device according to claim 12, wherein the solution (A) and the solution (B) are packaged in a two-compartment container.

15. The device according to claim 12, wherein: the solution (A) is at pH 7 and comprises Col-1 colloids non-covalently bonded to an unsulfated polysaccharide, a source of bivalent metals, and Col-2 colloids covalently bonded with an agent capable of positively charging the colloid; and the solution (B) is at pH 3, and comprises an acidifier and a sulfated polysaccharide.

16. The device according to claim 15, wherein: Col-1 colloids are cerium dioxide colloids; the unsulfated polysaccharide is alginate; the source of bivalent metals is calcium carbonate; Col-2 colloids are platinum colloids with zero oxidation state, which is platinum whose core exhibits zero oxidation state, covalently bonded to an agent capable of positively charging the colloid, which is cysteamine; the acidifier is gluconolactone; and the sulfated polysaccharide is the compound corresponding to the INCI designation aphanothece sacrum polysaccharide.

17. The matrix according to claim 2, wherein the unsulfated polysaccharide is alginate.

18. The matrix according to claim 3, wherein the sulfated polysaccharide is aphanothece sacrum polysaccharide.

19. The method according to claim 9, wherein the source of divalent metals is an alkaline earth metal and the agent capable of positively charging the colloid is cysteamine.

20. The method according to claim 10, wherein: the calcium salt is calcium carbonate, the Col-2 colloids are of platinum with a core of zero oxidation state, and the agent capable of positively charging the colloid is cysteamine.

Description

[0194] The invention and the advantages resulting therefrom will emerge more clearly from the following figures and examples, given in order to illustrate the invention and not in a limiting manner.

[0195] FIG. 1 shows the diffractogram of CeO.sub.2 colloids before non-covalently bonding with alginate.

[0196] FIG. 2 shows the diffractogram of Pt colloids before covalently bonding with aphanothece sacrum polysaccharide (INCI), modified by adding thiol groups.

[0197] FIG. 3 shows the degradation activity of ABTS (in %) of the bipolymeric matrix according to the invention compared to 2 commercial products, as a function of time (in minutes).

EXEMPLARY EMBODIMENTS OF THE INVENTION

1/Synthesis of Cerium Dioxide Colloids (Col-1) According to the Invention

[0198] 0.1-2 mmol of dextrose or myo-inositol and 0.5-5 equivalents of a cerium dioxide precursor such as cerium chloride are dissolved in 10-100 mL of water. When dissolved, 1-10 equivalents of ammonia are added. The solution is kept under stirring for 1-5 h. Acetone is added as a counter solvent to allow purification by centrifugation. The pellet is redispersed in water at the desired concentration.

[0199] The result of this synthetic process is cerium dioxide colloids coated with dextrose or myo-inositol. In this complex, dextrose and myo-inositol perform a role of controlling the size of the particles and the narrow dispersion of the size of the particles around an average size.

2/Synthesis of Platinum Colloids (Col-2) According to the Invention, for Covalent Bonding with a Sulfated Polysaccharide

[0200] A solution is prepared from 0.1 to 10 mmol of gluconolactone dissolved in 10 to 100 mL of water and then heated to reflux.

[0201] When reflux is reached, 0.01 to 10 mmol of a colloidal platinum precursor salt such as chloroplatinic acid and 0.001 to 1 mmol of polyvinylpyrrolidone (PVP), dissolved in 10 to 100 mL of water, are added to the reaction medium.

[0202] The solution is permitted to reflux for 1 to 5 hours.

[0203] The solution is then cooled to room temperature and acetone is added as a counter solvent to allow purification by centrifugation. The pellet is then dispersed to the desired concentration in the water.

[0204] The result of this synthetic process is platinum colloids dispersed in PVP. These colloids may be covalently bonded to a sulfated polysaccharide according to the invention, for example aphanothece sacrum polysaccharide (INCI), modified by adding thiol groups, the hemisynthesis of which is described in Example 3.

3/Hemi-Synthesis of Aphanothece Sacrum Polysaccharide (INCI), Modified by Adding Thiol Groups

[0205] 10 to 100×10-7 mmol of aphanothece sacrum polysaccharide are dissolved in 10 to 100 mL of water and the solution is stirred.

[0206] 100,000-100,000,00×10-7 mmol of N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride are added. The solution is kept under stirring for 10 to 100 min.

[0207] 1,000,000 to 100,000,000×10-7 mmol of cysteine are added, the solution is kept under stirring until the solid dissolves. The pH is adjusted to 4.

[0208] The solution is kept under stirring for 6 to 24 hours. The pH is then adjusted to 6.

[0209] The solution is poured into approximately ten times its volume of ethanol in order to precipitate the aphanothece sacrum polysaccharide modified by adding thiol groups and recover this compound by centrifugation before dissolving it in a minimum of water (solution at 1-5% by mass) to be lyophilized.

4/Synthesis of Platinum Colloids (Col-2) According to the Invention, for Non-Covalent Bonding with the Sulfated Polysaccharide

[0210] 0.1-10 mmol of gluconolactone is dissolved in 10-100 mL of water and the solution is heated to reflux.

[0211] When reflux is reached, 0.1-1 equivalent of a colloidal platinum precursor salt such as chloroplatinic acid and 0.01-0.1 equivalent of polyvinylpyrrolidone (PVP) dissolved in 10-100 mL of water are added to the reaction medium.

[0212] The solution is kept at reflux for 1-5 h. The solution is cooled to room temperature and 0.1-1 equivalent of cysteamine hydrochloride are added. The solution is kept under stirring for 1-5 hours and then acetone is added as a counter solvent to allow purification by centrifugation. The pellet is then dispersed to the desired concentration in the water.

[0213] The result of this synthetic process is platinum colloids modified by the addition of cysteamine and dispersed in PVP. These colloids may be non-covalently bonded (Coulomb interaction) to a sulfate polysaccharide, for example aphanothece sacrum polysaccharide (INCI).

5/CeO.SUB.2./Alginate and Pt/Aphanothece Sacrum Polysaccharide Colloids According to the Invention

[0214] The small size of the CeO.sub.2 and Pt particles makes it possible to have a larger area to cover and therefore to bond a greater number of molecules to the surface of each of the particles.

[0215] The diffractograms were measured on powder with an XRD of Cu-Kα source in transmission.

[0216] The diffractogram of CeO.sub.2 colloids, before non-covalent bonding with alginate, is shown in FIG. 1.

[0217] The diffractogram of Pt colloids, before covalent bonding with aphanothece sacrum polysaccharide modified by addition of thiol groups, is shown in FIG. 2.

6/Manufacturing Process of the Bipolymeric Matrix According to the Invention

[0218] Two solutions (A) and (B) are mixed in a proportion of 4/5 of solution (A) and 1/5 of solution (B).

[0219] Solution (A) comprises CeO.sub.2 colloids according to the invention, obtained from Example 1, and alginate, calcium carbonate, and Pt/aphanothece sacrum polysaccharide colloids according to the invention obtained from the mixture of reactions described in examples 2 and 3, and water;

[0220] Solution (B) includes native (unmodified) aphanothece sacrum polysaccharide (INCI) and gluconolactone dispersed in water.

[0221] Alternatively, solution A comprises CeO.sub.2 colloids according to the invention, obtained from example 1, alginate, calcium carbonate, platinum colloids according to example 4 and native (unmodified) aphanothece sacrum polysaccharide (INCI) and water; and solution B of native (unmodified) aphanothece sacrum polysaccharide and gluconolactone dispersed in water.

[0222] After mixing, the three-dimensional bipolymeric matrix according to the invention is formed in a few minutes (1-5 minutes), or even seconds (less than a minute) by entanglement of the 2 crosslinked polymer networks according to the invention.

7/Determination of the Antioxidant Activity of the Three-Dimensional Bipolymeric Matrix According to the Invention

[0223] The bipolymeric matrix according to the invention comprises: [0224] a quantity of Col-1 colloids non-covalently bonded with alginate which represents between 0.01 and 1% by weight of the matrix; [0225] a quantity of Col-2 colloids covalently bonded to aphanothece sacrum polysaccharide modified by addition of thiol groups, which represents between 0.001 and 0.1% by weight of the matrix; [0226] a quantity of water which represents between 70 and 99% by weight of the matrix.

[0227] A stock solution of ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) at 14 mM is incubated, at equal volume, with a 4.9 mM solution of a hydraulic solution of ammonium persulfate to produce a cationic ABTS radical. The reaction mixture is incubated in the dark for 16 hours at room temperature. The solution obtained is diluted to 1/100 with phosphate buffer (0.2 M, and pH 7.4) containing 150 mM of NaCl to obtain an absorbance of 1.5 at 734 nm.

[0228] Samples of different masses of between 1.2 and 12 mg of the three-dimensional bipolymeric matrix according to the invention are dispersed at 240 g/L in water and are added to 2970 μL of the cationic ABTS solution of 0.07 mM in water, then placed under stirring in the dark.

[0229] After 30 minutes of incubation, the ABTS is completely degraded.

[0230] The product is mixed with 3000 μL of the ABTS solution, as prepared above, in a polymethyl methacrylate ultraviolet (UV) spectrophotometry vessel. The reaction mixture is incubated in the dark for 30 minutes at room temperature. Then, the absorbance is measured every 20 minutes.

[0231] The antioxidant property of the bipolymeric matrix according to the invention is compared with two commercial products: [0232] the Nu-Gel® dressing corresponding to a hydrogel containing sodium alginate for the treatment of dry, fibrinous or necrotic sores; [0233] the Flaminal Hydro® dressing corresponding to a gel comprising alginate and an antimicrobial enzymatic system.

[0234] The data is shown in FIG. 3.

[0235] The results show that after 120 hours, approximately 85% of ABTS has been degraded by the bipolymeric matrix according to the invention, while the Nu-Gel® and Flaminal Hydro® dressings degrade approximately 18% and 27% of ABTS, respectively.

[0236] In conclusion, the antioxidant activity of the solution containing the bipolymeric matrix according to the invention is exponential and much greater compared to those of the 2 commercial dressings.

8/Determination of the Absorption Capacity of Exudates by the Three-Dimensional Bipolymeric Matrix According to the Invention

[0237] The absorption capacity of exudates by the bipolymeric matrix according to the invention was compared with various commercial products indicated for the treatment of exudative or even very exudative sores.

[0238] An exudate solution is prepared by mixing 50 mL of fetal calf serum and 50 mL of a diluent containing 0.1% peptone and 0.9% sodium chloride. The sheet dressings are cut so as to obtain an area of 1.98 cm.sup.2. The gel dressings are poured so as to cover an area of 1.98 cm.sup.2.

[0239] Each sample is placed in a Petri dish 3 cm in diameter, then weighed (m0). Each dressing is covered with 4 mL of exudate before sealing the Petri dishes and storing them at 21° C. for 72 hours. The remaining exudate is removed from each dish and each sample is reweighed (ml).

[0240] The exudate absorption capacity of each dressing is determined according to the following formula:

[00001]$\begin{array}{cc}\mathrm{Absorption}\mathrm{capacity}=\frac{m1-m0}{m0}\times 100& \left[\mathrm{Math}1\right]\end{array}$

[0241] The results are shown in Table 1 below.

TABLE-US-00001 TABLE 1 Dressing Permafoam Biatain Intrasite Hydrotac Tegarderm Duoderm Bipolymeric brand Comfort Adhesive Conformable Hydrocolloid Extra Thin matrix Thin according to the invention Type Hydrofiber Hydrocellular Hydrogel Hydrogel Hydrocolloid Hydrocolloid Hydrogel sheets sheets sheets Absorption 66.25 101.60 11.64 35.41 19.81 30.90 15.36 after 60 h (g/100 cm.sup.2)

[0242] The results show that the hydrofiber and hydrocellular type dressings, indicated for exudative or even very exudative sores, have better absorption with 65 to 100 g/cm.sup.2 of exudate absorbed.

[0243] The hydrogel-type sheet dressings absorb 10-35 g/cm.sup.2 of exudate.

[0244] Hydrocolloid-type dressings, indicated for the treatment of low-exudative sores, absorb between 20 and 30 g/cm.sup.2 of exudate.

[0245] The bipolymeric matrix according to the invention absorbs 15 g/cm.sup.2 of exudate, placing it in hydrogel-type sheet dressings. This is the only sheet hydrogel in liquid form to withstand the exudate absorption test, since the 2 commercial hydrogels evaluated (Intrasite Conformable and Hydrotac) partially or completely dissolved in the exudate.

[0246] This is explained by the crosslinking of the bipolymeric matrix according to the invention which allows the exudate to be absorbed while maintaining the shape of the dressing.

[0247] In addition, absorption of exudate occurs slowly, gradually, allowing rearrangement of the bipolymeric matrix. On the contrary, the commercial products tested absorb exudate like a sponge. As a result, after saturation, these products can no longer absorb exudate and are therefore no longer effective.