COMPOSITION FOR DELIVERING NITRIC OXIDE TO SKIN

Abstract

A skin application composition comprising a first component comprising S-nitrosothiol in dry inactive condition is provided.

Claims

1. A skin application composition comprising a first component comprising S-nitrosothiol in dry inactive condition.

2. The skin application composition according to claim 1, wherein the skin application composition is a skin dressing.

3. The skin application composition according to claim 1, wherein the first component is a solid material.

4. The skin application composition according to claim 3, wherein the solid material comprises a polymer material.

5. The skin application composition according to claim 4, wherein the polymer material comprises polyvinyl alcohol or polyvinyl pyrrolidone or a mixture thereof.

6. The skin application composition according to claim 3, wherein the solid material is in the form of a sheet, a layer or a slab.

7. The skin application composition according to claim 1, wherein the first component is a porous water-absorbable material.

8. The skin application composition according to claim 1, wherein the first component comprises a non-aqueous liquid matrix containing the S-nitrosothiol dispersed therein.

9. The skin application composition according to claim 1, wherein the first component comprises a chelating agent capable of chelating divalent metal ions.

10. The skin application composition according to claim 1, which comprises a second component comprising a source of water.

11. The skin application composition according to claim 10, wherein the second component comprises a source of divalent metal ions.

12. The skin application composition according to claim 9, wherein the concentration of divalent metal ions exceeds the capacity of the chelating agent to chelate divalent metal ions.

Description

EXAMPLES

[0067] A number of model systems were prepared to demonstrate the release rate of S-nitrosothiols. The systems are detailed in tables at the start of each results section below. For each system, sample aliquots from the aqueous component were taken, at three time points after the system ‘activation’ (i.e. all components being brought together) to confirm the presence of S-nitrosothiol release. The first time-point was always t=zero (i.e. measuring S-nitrosothiol in the aqueous component prior to being ‘activated’ with the dry/non-aqueous component to demonstrate there was no S-nitrosothiol at the start, which was the case in all systems), then t=2 hours after activation and finally t=6 hours after activation.

[0068] Materials [0069] Sodium nitrite (300 mM) in DI water [0070] Glutathione (300 mM) in DI water [0071] Lactic acid (100 mM) in DI water—(adjusted to pH 4.0 with 0.2 M NaOH) [0072] Sorbitol (1 M) in DI water [0073] Polyvinyl alcohol (7.5% w/w) in DI water—M.sub.w 31,000-50,000, 98-99% hydrolyzed—obtained from Sigma (363138) [0074] EDTA (disodium) (5 mM) in DI water [0075] Copper (2+) Nitrite (5 mM) in DI water

[0076] PVA Stock Solution Manufacture Procedure

[0077] 462.5 ml of DI water was measured out and heated on hot plate to constant temperature between 80-85° C. —controlled with digital thermometer. 37.5 g PVA powder was measured out and divided onto 5×7.5 g aliquots. Single aliquots of the PVA powder were added to the heated water which was being stirred (preventing PVA coagulation). Throughout the additions, the water/PVA temperature was maintained at 80-85° C. Additions were repeated while maintaining the temperature of the water/PVA mix until the PVA is dissolved. After removal from the hotplate and cooling, the final volume was made up to 500 ml with DI water.

[0078] PVA Films Manufacture

[0079] PVA films were produced by mixing the PVA stock solution with active components and allowing the mixture to dry in a Petri plate at 40° C. 20 ml of each pre-prepared PVA solution comprising the active components was poured into 10×10 cm Petri plates and left to dry overnight in an incubator at 40° C. The composition of the PVA mixtures prior to drying is shown in Table 1. Glutathione and nitrite were allowed to react together to form S-nitrosothiol prior to formation of the PVA film.

[0080] The PVA films comprising S-nitrosothiol were subsequently used to follow the rate of S-nitrosothiol release after being brought in contact with an aqueous system.

TABLE-US-00001 TABLE 1 Film ID Film Components PVA4 PVA (5% w/w) Glutathione (30 mM) Sodium nitrite (30 mM) Lactic acid (5 mM) at pH 4.0 PVA5 PVA (5% w/w) Glutathione (30 mM) Sodium nitrite (30 mM) Lactic acid (5 mM) EDTA (0.05 mM) at pH 4.0

[0081] Powder Manufacture

[0082] Powders comprising an S-nitrosothiol were produced by mixing glutathione and sodium nitrite in aqueous sorbitol background, allowing the glutathione and sodium nitrite to react and form S-nitrosothiol, followed by drying the mixture. For each powder, 20 ml of each pre-prepared solution was poured into 10×10 cm Petri plates and left to dehydrate for 24 hours in an incubator at 40° C., followed by a thorough desiccation. Once in powder form, the formulations were dispersed in neat Propylene Glycol (0.1 g of powder to 1 ml Propylene Glycol).

[0083] The composition of the aqueous mixtures for powder preparation prior to drying is shown in Table 2.

[0084] The powders comprising S-nitrosothiol, suspended in non-aqueous Propylene Glycol were subsequently used to follow the rate of S-nitrosothiol release after being brought in contact with an aqueous system.

TABLE-US-00002 TABLE 2 Powder ID Powder Components P3 Sorbitol (500 mM) Glutatthione (30 mM) Sodium nitrite (30 mM) Lactic acid (5 mM) at pH 4.0 P4 Sorbitol (500 mM) Glutathione (30 mM) Sodium nitrite (30 mM) Lactic acid (5 mM) EDTA (0.05 mM) at pH 4.0

[0085] Impregnated Foams Manufacture

[0086] Impregnated foams comprising S-nitrosothiol were produced by allowing the foam to absorb an aqueous solution comprising glutathione and sodium nitrite, allowing the glutathione and sodium nitrite to react and form S-nitrosothiol, followed by thorough drying at 40° C.

[0087] ActivHeal™ (Advanced Medical Solutions) foam was used.

[0088] The composition of the aqueous mixtures for impregnated foam preparation prior to drying is shown in Table 3.

[0089] The impregnated foams comprising S-nitrosothiol were subsequently used to follow the rate of S-nitrosothiol release after being brought in contact with an aqueous system.

TABLE-US-00003 TABLE 3 Foam ID Impregnated Foam Components F1 Glutathione (30 mM) Sodium nitrite (30 mM) Lactic acid (5 mM) at pH 4.0 F2 Glutathione (30 mM) Sodium nitrite (30 mM) Lactic acid (5 mM) EDTA (0.05 mM) at pH 4.0

[0090] For impregnated foams production, 20 mls of each pre-prepared component solution was poured into 10×10 cm Petri plates. 4×4 cm.sup.2 pieces of the foam dressing were placed into the solution and the solution allowed to soak into the dressings over 4 hours. The foam dressing pieces were then removed and dried overnight in an incubator at 40° C.

[0091] Aqueous Components

[0092] The pre-prepared PVA films/Powders/Impregnated Foams require contact with an aqueous component to activate S-nitrosothiol generation. The aqueous components used are shown in Table 4.

TABLE-US-00004 TABLE 4 AQ ID Aqueous Component AQ1 Sheet hydrogel AQ2 Sheet hydrogel imbibed with 5 mM Copper Nitrite Solution (50 μL of Cu(NO.sub.3).sub.2 per 1 cm.sup.2 hydrogel) AQ3 Amorphous Hydrogel AQ4 Amorphous Hydrogel (50 μL of 5 mM Cu(NO.sub.3).sub.2 per 1 cm2 hydrogel) AQ5 DI water AQ6 0.2 mM Cu(NO.sub.3).sub.2 Solution (in DI water)

[0093] Details of the sheet hydrogel and amorphous hydrogel materials are shown in Table 5.

TABLE-US-00005 TABLE 5 Component Name Manufacturer Details Sheet ActiformCool Activa 70% H.sub.2O:30% hydrogel Acrylic Polymer (Taurate derivative). Phenoxyethanol as preservative. Used in moderate to heavily exuding wounds Amorphous ActivHeal Advanced Medical Hydrogel with high Hydrogel Solutions water content - 85%. Used in nil to low exudate wounds

[0094] S-Nitrosothiol Measurement

[0095] The presence of S-nitrosothiols was measured by an Absorbance reading at 490 nm using the Griess reagent method described below. S-nitrosothiol concentration can be calculated from the absorbance measurement using the extinction coefficient of ca. 10,000 M.sup.−1 cm.sup.−1. Absorbance measurement was carried out using Fisherbrand™ Digital Colorimeter Model 45.

[0096] Two different methods were required to measure S-nitrosothiol concentration depending on whether a Hydrogel (AQ1 to AQ4) or a Solution (AQ5 and AQ6) were utilised as the aqueous component.

[0097] Reagents for S-Nitrosothiol Measurement [0098] Reagent 1: Na-phosphate buffer (pH 7.4, 0.1 M). [0099] Reagent 2: Griess reagent: 20 mg of N-(1-Naphthyl)ethylendiamine dihydrochloride (NADD)+500 mg of sulphanilamide dissolved in 2 mL of DMSO. [0100] Reagent 3: Mercuric chloride (10 mM) in DMSO (13.58 mg of HgCl2 in 5 mL of DMSO).

[0101] Procedure to Measure S-Nitrosothiol Concentration in Gels [0102] 1. Dispense 25 mL of Reagent 1 and 825 μL of Reagent 2 into a 250 ml pot [0103] 2. Weigh accurately 300 mg of the hydrogel and immerse it in the reagent mix. Incubate while shaking mildly for 30 min. [0104] 3. Transfer 2.6 ml of the reagent mix from the pot into a plastic cuvette [0105] 4. Add 25 μl of Reagent 3 [0106] 5. Read absorbance of the resulting mixture at 490 nm in 10 min

[0107] Procedure to Measure S-Nitrosothiol Concentration in Solutions [0108] 1. Dispense 1.5 mL of Reagent 1 into a plastic cuvette [0109] 2. Add 200 μL of the sample [0110] 3. Add 1.17 μL of DI water [0111] 4. Add 100 μL of Reagent 2 [0112] 5. Add 30 μL of Reagent 3 and mix thoroughly [0113] 6. Read absorbance of the resulting mixture at 490 nm in 10 min

[0114] Results

[0115] S-Nitrosothiol Measurements in PVA Film Systems

[0116] Release of S-nitrosothiol from PVA film systems following activation by contact with aqueous systems is shown in Table 6. In each case the measurements were repeated, and the results are shown in mAU.

TABLE-US-00006 TABLE 6 Aqueous Absorbance Absorbance Absorbance PVA film component at t = 0 at 2 hours at 6 hours PVA4 Aq1 0 10 60 0 10 50 PVA4 Aq2 0 0 60 0 0 40 PVA4 Aq3 0 70 90 0 70 80 PVA4 Aq4 0 20 40 0 20 50 PVA5 Aq1 0 10 20 0 0 20 PVA5 Aq2 0 20 30 0 10 30 PVA5 Aq3 0 40 80 0 40 90 PVA5 Aq4 0 20 100 0 20 90

[0117] S-Nitrosothiol Measurements in Foam Based Systems

[0118] Release of S-nitrosothiol from foam based systems following activation by contact with aqueous systems is shown in Table 7. In each case the measurements were repeated, and the results are shown in mAU.

TABLE-US-00007 TABLE 7 Foam Aqueous Absorbance Absorbance Absorbance component component at t = 0 at 2 hrs at 6 hours Foam 1 Aq1 0 30 90 0 20 90 Foam 1 Aq2 0 20 40 0 20 40 Foam 1 Aq3 0 70 90 0 60 80 Foam 1 Aq4 0 70 80 0 70 90 Foam 1 Aq5 0 820 750 0 920 810 Foam 1 Aq6 0 370 440 0 360 390 Foam 2 Aq1 0 0 0 0 0 0.00 Foam 2 Aq2 0 30 20 0 40 20 Foam 2 Aq3 0 190 230 0 160 210 Foam 2 Aq4 0 170 230 0 180 250 Foam 2 Aq5 0 670 920 0 500 740 Foam 2 Aq6 0 810 690 0 820 750

[0119] S-Nitrosothiol Measurements in Systems Based on a Non-Aqueous Liquid Component

[0120] Release of S-nitrosothiol from powder based non-aqueous systems following activation by contact with aqueous systems is shown in Table 8. In each case the measurements were repeated, and the results are shown in mAU.

TABLE-US-00008 TABLE 8 Non-aqueous Aqueous Absorbance Absorbance Absorbance component 1 component at t = 0 at 2 hrs at 6 hours P3 Aq3 0 30 50 0 30 50 P3 Aq4 0 40 30 0 30 30 P3 Aq5 0 80 50 0 80 50 P3 Aq6 0 70 0 0 70 0 P4 Aq3 0 10 40 0 0 30 P4 Aq4 0 0 0 0 0 0 P4 Aq5 0 80 60 0 70 60 P4 Aq6 0 50 0 0 30 0

CONCLUSIONS

[0121] Release of S-nitrosothiol from non-aqueous components based on PVA films, a foam based systems and powder based systems was demonstrated on contact with an aqueous component.