PH INDICATOR DRESSING
Disclosed herein are devices, wound dressings and methods for determining the pH of wound exudate at a wound. Example devices include a device comprising a surface configured to contact the wound and a pH indicator applied to the surface, wherein the pH indicator has a first colour prior to contact with the wound exudate and changes colour as a function of the pH of the wound exudate.
1 . A device for determining the pH of a wound exudate comprising a surface configured to contact the wound and a pH indicator applied to the surface, wherein the pH indicator has a first colour prior to contact with the wound exudate and changes colour as a function of the pH of the wound exudate.
2 . The device according to claim 1 , wherein the colour change in the pH indicator is detectable at a 0.1 unit interval change in pH.
3 . The device according to claim 2 , wherein the colour change in the pH indicator is detectable between about pH 5 and about pH 10.
4 . The device according to claim 3 , wherein the colour change in the pH indicator is detectable between about pH 5.5 and about pH 9.5.
5 . The device according to claim 3 or 4 , wherein the colour change in the pH indicator is detectable between about pH 6.5 and 9.5.
6 . The device according to any of claims 1 to 5 , wherein the pH indicator comprises a phenylazo compound.
7 . The device according to claim 6 , wherein the phenylazo compound is selected from the group listed in Table 1.
8 . The device according to claim 6 or 7 , wherein the pH indicator comprises a combination of phenylazo compounds.
9 . The device according to any of claims 1 to 8 , wherein the device is a conformable non-woven, mesh or perforated film.
10 . The device according to claims 1 to 9 , wherein the device is used in combination with a secondary dressing.
11 . The device according to claim 10 , wherein the device is the wound contacting layer of a wound dressing.
12 . A wound dressing comprising:
(a) a wound-contacting surface,
(b) an opposing non-wound contacting surface,
(c) a pH indication zone comprising a pH indicator which indicates the pH of a wound exudate, wherein the colour of the pH indicator changes in response to a change in the pH of the wound exudate; and,
(d) at least one conduit for directing wound exudate towards the pH indication zone.
13 . The wound dressing according to claim 12 , wherein the dressing has an outer surface and wherein a pH indication zone is located at or near the outer surface.
14 . The wound dressing according to claim 13 , wherein the dressing has a peripheral edge extending between the wound-contacting surface and the opposing non-wound contacting surface and wherein the outer surface is the peripheral edge.
15 . The wound dressing according to any of claims 12 to 14 , wherein the at least one conduit directs wound exudate laterally towards the pH indication zone.
16 . The wound dressing according to any of claims 12 to 15 , wherein the colour change in the pH indicator is detectable at a 0.1 unit interval change in pH.
17 . The wound dressing according to claim 16 , wherein the colour change in the pH indicator is detectable between about pH 5 and about pH 10.
18 . The wound dressing according to claim 17 , wherein the colour change in the pH indicator is detectable between about pH 5.5 and about pH 9.5.
19 . The wound dressing according to claim 17 or 18 , wherein the colour change in the pH indicator is detectable between about pH 6.5 and about pH 9.5.
20 . The wound dressing according to any of claims 12 to 19 , wherein the pH indicator comprises a phenylazo compound.
21 . The wound dressing according to claim 20 , wherein the phenylazo compound is selected from the group listed in Table 1.
22 . The wound dressing according to claim 20 or 21 , wherein the pH indicator comprises a combination of phenylazo compounds.
23 . A formulation for indicating pH of a wound exudate comprising a dye that includes a phenylazo compound and wherein a colour of the phenylazo compound changes in response to a change in the pH of the wound exudate.
24 . The formulation according to claim 23 , wherein the phenylazo compound is selected from the group listed in Table 1.
25 . The formulation according to claim 23 or 24 , wherein the dye comprises a combination of phenylazo compounds.
26 . The formulation according to any of claims 23 to 25 , wherein the colour change in the pH indicator is detectable at a 0.1 unit interval change in pH.
27 . The formulation according to claim 26 , wherein the colour change in the pH indicator is detectable between about pH 5 and about pH 10.
28 . The formulation according to claim 27 , wherein the colour change in the pH indicator is detectable between about pH 5 and about pH 9.5.
29 . The formulation according to claim 27 , wherein the colour change in the pH indicator is detectable between about pH 6.5 and about pH 9.5.
30 . A method for monitoring the pH of a wound, the method comprising the steps of:
(a) providing a device comprising a surface configured to contact the wound, said surface having a pH indicator applied thereto, wherein the pH indicator has a first colour prior to contact with the wound exudate and changes colour as a function of the pH of the wound exudate;
(b) applying the device to the wound; and,
(c) assessing the colour of the pH indicator.
31 . The method according to claim 30 , further comprising the step of combining the device with a secondary dressing prior to applying the device to the wound.
32 . The method according to claim 31 , wherein the combining step comprises adhering the device to the secondary dressing.
33 . The method according to claim 31 or 32 , wherein the device forms the wound contacting surface of the secondary dressing.
34 . The method according to any of claims 31 to 33 , further comprising the step of removing the combination of the device and the wound dressing prior to assessing the colour of the pH indicator.
35 . A wound dressing comprising a wound contacting surface having a pH indicating means wherein the pH indicating means has a first colour prior to contact with the wound exudate and changes colour as a function of the pH of the wound exudate.
36 . A wound dressing comprising:
(a) a pH indicating means wherein the pH indicating means has a first colour prior to contact with wound exudate and changes colour as a function of the pH of the wound exudate; and,
(b) a conduit means for directing the wound exudate towards the pH indicating means.
37 . A system for detecting pH of a wound exudate, comprising at least one of a device of any of claims 1 - 11 , a wound dressing of any of claim 12 - 22 , or 35 - 36 , and a formulation of any of claims 23 - 29 .