WO2022147269A1

WO2022147269A1 - System and method for time expiration reminder for medical care

Info

Publication number: WO2022147269A1
Application number: PCT/US2021/065707
Authority: WO
Inventors: Stephanie A. HAMMER-KRABBE; Thomas M. KRABBE
Original assignee: Claralert, Inc.
Priority date: 2020-12-31
Filing date: 2021-12-30
Publication date: 2022-07-07
Also published as: WO2022147269A4

Abstract

A user actuatable time expiration reminder does not depend on electronic or powered means, but rather on predictable and well understood chemical processes. Uses include, but are not limited to, medical bandages or dressings to let the patient or caregiver know that it is time to change a bandage or dressing. In one embodiment, a liquid filled bladder is deliberately ruptured whereby the liquid causes a color indicator to show that actuation has occurred. After a predetermined time, the liquid dissolves a coating that surrounds a separately located dye, thus releasing the dye and revealing an image at (but not before) a time corresponding to the preferred expiration time.

Description

System and Method for Time Expiration Reminder for Medical Care

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of United States Provisional Patent Application Nos. 63/132,507 (filed December 31, 2020), 63/143,308 (filed January 29, 2021) and 63/249,351 (filed September 28, 2021). Each of the foregoing applications is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

[0002] This disclosure relates to visual time expiration reminders. More particularly, this disclosure relates to systems and methods of visual time alert reminders that change color and/or present a colored or distinctive mark, image or pattern after passage of a predetermined length of time to clearly indicate that an action must be taken.

BACKGROUND

[0003] It is well known that bandages and medical dressings require changing from time to time, according to the care instruction that patients are given by a trained medical professional. Over time, bandages and dressings can become saturated, contaminated, or otherwise outlive their period of use. The need for timely changes is particularly acute in home care because untrained (also known as family) caregivers and patients themselves (in the absence of a trained medical provider) must visually supervise wounds and be on the lookout for signs of potential infection. Untrained caregivers and patients need to perform bandage changes in a timely manner, but they may not have the training to recognize when bandages should be changed. Even supervised care environments have multiple personnel involved in care because of shift changes, and a dressing change may be inadvertently missed because of failed communication or another reason. In addition, both trained and/or untrained caregivers and/or patients may also be overworked,

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SUBSTITUTE SHEET (RULE 26) emotionally overloaded, under significant stress and/or juggling many responsibilities and may simply forget that it is time to change a bandage. A forgotten change could lead to infection, or worse.

[0004] Existing time alert reminders that might hypothetically be deployed in a bandage or dressing environment do not use color, image or the combination of color and image to show whether a predetermined length of time has expired. They are not particularly well suited for home healthcare environments in which laypeople are not well trained, barely trained or not even trained at all to perform complex medical care, which includes bandage changes. Most provide a gradual color change or gradual presentment of a colored mark. However, the gradual nature of such color changes makes it difficult for an observer to draw conclusions about the proper time for the change. What is needed is a time alert reminder that is essentially binary, straightforward to deploy, and is well suited for a medical context (both home care and supervised care). A reminder needs to be clear and unmistakable to minimize the chance of confusion or ambiguity about whether the time has come for a bandage or dressing change.

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SUBSTITUTE SHEET (RULE 26) SUMMARY OF THE INVENTION

[0005] A time expiration reminder may be attached to an object, such as a bandage or other temporary medical dressing, where it is desirable to know whether the object has been in use for a certain length of time. After being activated, the time alert reminder will typically change color and/or display an image or otherwise indicate when a predetermined length of time is over.

[0006] A time expiration reminder supports regular visual supervision of wounds by both untrained and trained caregivers and patients themselves because after the predetermined time period is over, the invention clearly and continuously displays a color and/or image combination to visually remind users that an action must be taken. Time alerts support caregivers and patients in following care instructions they receive from trained medical professionals. Time alerts as disclosed herein are multicultural and accessible to people with all levels of literacy since they are color and picture based. The combination of color and image ensures that color blind people and people with low vision can also use them.

[0007] In a first embodiment, a time alert reminder sleeve has a containment around a color source (such as a dissolvable capsule) and a bladder containing a solution. When a user presses down on the bladder, the bladder ruptures, expelling the solution into the sleeve. After a predetermined length of time, the solution dissolves the capsule, releasing a dye tablet in the capsule into the solution. The dye tablet then dissolves in the solution, rapidly changing the color of the solution to indicate that the predetermined length of time is over. A window (preferably with appropriate iconography) can display the color through the sleeve.

[0008] In a second embodiment, a time alert reminder patch has two strips of litmus paper separated by a barrier and a bladder containing a solution. When a user presses down on the bladder, the bladder ruptures, expelling the solution onto the first strip of litmus paper. The solution

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SUBSTITUTE SHEET (RULE 26) migrates through the first strip of litmus paper causing an immediate color change to provide a clear indication to the user that the process has started. Then, the solution migrates to the barrier, and after a predetermined length of time, dissolves the barrier. The solution then migrates through the second strip of litmus paper, rapidly changing the color to indicate that the predetermined length of time is over.

[0009] In a third embodiment, a time alert reminder bandage has a time-release color printed on top or woven in. After being activated, the time-release color changes color or presents a colored mark to indicate that a predetermined length of time is over.

[0010] These as well as other embodiment, advantages, and alternatives, will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying drawings.

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SUBSTITUTE SHEET (RULE 26) BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 shows a sleeve of a first embodiment in its initial configuration.

[0012] FIG. 2 shows the sleeve of the first embodiment in its initial configuration, without the cover.

[0013] FIG. 3 shows the sleeve of the first embodiment, after the bladder has been ruptured but before the capsule has dissolved.

[0014] FIG. 4 shows the sleeve of the first embodiment after the bladder has been ruptured but before the capsule has dissolved, without the cover.

[0015] FIG. 5 shows the sleeve of the first embodiment after the capsule has dissolved and the dye tablet has mixed with the solution from the bladder.

[0016] FIG. 6 shows the sleeve of the first embodiment after the capsule has dissolved and the dye tablet has mixed with the solution from the bladder, without the cover.

[0017] FIG. 7 shows the capsule of the first embodiment.

[0018] FIG. 8 shows the capsule of the first embodiment inside a cage.

[0019] FIG. 9 shows a patch of a second embodiment in its initial configuration with two strips of litmus paper and a barrier on a base layer, and a bladder containing a solution positioned on the first strip of litmus paper, without the cover.

[0020] FIG. 10 shows the patch of the second embodiment in its initial configuration.

[0021] FIG. 11 shows the patch of the second embodiment after the bladder has been ruptured but before the barrier has dissolved, without the cover.

[0022] FIG. 12 shows the patch of the second embodiment after the bladder has been ruptured but before the barrier has dissolved.

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SUBSTITUTE SHEET (RULE 26) [0023] FIG. 13 shows the patch of the second embodiment after the barrier dissolves, without the cover.

[0024] FIG. 14 shows the patch of the second embodiment after the barrier dissolves.

[0025] FIG. 15 shows a bandage of a third embodiment with time-release ink before the time-release ink has activated.

[0026] FIG. 16 shows the bandage of the third embodiment after the time-release ink has activated.

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SUBSTITUTE SHEET (RULE 26) DETAILED DESCRIPTION

[0027] Example systems and methods are described herein. It should be understood the words “example” and “exemplary” are used herein to mean “serving as an example, instance, or illustration.” Any embodiment or feature described herein as being an “example” or “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or features. In the following detailed description, reference is made to the accompanying figures, which form apart thereof. In the figures, symbols typically identify similar components, unless context dictates otherwise. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein.

[0028] The example embodiments described herein are not meant to be limiting. It will be readily understood that the embodiments of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

I. Introduction

[0029] Time alert reminders of the present invention may be applied to any object where it is desirable to know whether the object has been in use for a certain amount of time, such as bandages or other temporary medical dressings; medical equipment or devices that must be connected or disconnected after a certain time period, such as feeding tubes or ostomy plates; ophthalmology “eye training” patches; pharma products that must be replaced or changed after a certain time period, such as birth control patches; or walls in areas that must be cleaned after a certain time period.

[0030] For example, when applied to bandages, time alert reminders of the present invention support caregivers and patients themselves and allow them to see “at a glance” when a

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SUBSTITUTE SHEET (RULE 26) bandage must be changed. This is especially important for untrained caregivers with little to no medical training who perform wound care in a home setting. Failing to timely change bandages can lead people to inadvertently miss signs of possible infection, can slow the healing process, and can encourage infection.

[0031] Time expiration reminders of the present invention may be pre-applied to objects by the time of sale. Alternatively, time expiration reminders of the present invention may be sold separately and applied as needed at the time of use. It will be appreciated that the time expiration reminders described herein do not rely on electronic or powered means, but instead depend solely on predictable and well understood chemical processes.

II. Sleeve with Dissolvable Capsule

[0032] Figures 1-8 depict a first embodiment of a time alert reminder sleeve 100. The sleeve 100 contains a strip of pH paper 106, a capsule 110, and a bladder 114, each affixed to the inside of the sleeve 100 using adhesive. The capsule 110 contains a dye tablet, and the bladder 114 contains a solution 116 and has a seal 117 for the ends. The sleeve 100 is made of transparent plastic, such as polyethylene, and is securely sealed to prevent the escape of its contents.

[0033] Preferably, the clear top of the sleeve 100 is further covered by a white or otherwise opaque top 102 with two clear windows 104 and 108. Alternatively, an opaque sticker may be applied, or a white plastic sleeve may be used. A first window 104 is over the location of the pH paper 106, so that color peeking through will clearly indicate the “on” state of the “timer.” A second window 108 will reveal color after the amount of time has passed and the capsule 110 has dissolved, to be discussed below. The opaqueness of the cover 102 hides the underlying process from users ensure the user only sees a binary alert, e.g. when the time has passed. It is the purpose to conceal the dissolving capsule from the user in order to prevent confusion. The opaqueness of

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SUBSTITUTE SHEET (RULE 26) the cover 102 also emphasizes the color changes in the pH paper 106 and in the solution 116 by providing a contrast with the colors visible through the windows 104 and 108.

[0034] Figures 1 (with cover 102) and 2 (without cover 102) depict the sleeve 100 in its initial configuration. To activate the time alert reminder feature, a user presses down on the bladder 114, thereby rupturing the seal 117 and expelling the solution 116 into the sleeve 100. Figures 3 (with cover 102) and 4 (without cover 102) depict the sleeve 100 after the solution 116 has been expelled into the sleeve 100, but before the capsule 110 has dissolved. Figures 5 (with cover 102) and 6 (without cover 102) depict the sleeve 100 after the capsule 110 has dissolved and the dye tablet has mixed with the solution 116 from the bladder 114, indicating that a predetermined length of time has passed.

[0035] The bladder 114 is made of a plastic material with a cling seal like “GLAD Press’ N Seal” (The Glad Products Company, Oakland California), where one side of the material will stick to itself. The sticky side should be on the inside of the bladder 114 so that once the solution 116 is expelled, the inside of the bladder 114 will stick to itself and stay compressed. This prevents the bladder 114 from reinflating once the seal 117 is ruptured and the solution 116 is expelled into the sleeve 100. Alternatively, a container similar to an eye drop dispensers or a rupturable capsule could be used as the bladder 114.

[0036] The solution 116 of the present embodiment is made of 50% citric acid, CsHsO?, and 50% water. These ingredients are safe, cheap, and widely available. However, other compositions for the solution 116 may be used. Varying the acidity of the solution 116 affects the time to dissolve the capsule 110 and dye tablet and the color change produced on the pH paper 106.

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SUBSTITUTE SHEET (RULE 26) [0037] The pH paper 106 is adhesively affixed to the top of the sleeve 100. After the solution 116 is expelled into the sleeve 100 and comes into contact with the pH paper 106, the solution 116 will instantly turn the pH paper 106 a different color to indicate that the time alert reminder is activated. For example, the Hydrion® (93) S/R Inst-Chek Disp 0.0-13.0 pH paper may be used. This pH paper is initially yellow in color and changes to a red or orange color in the presence of an acidic solution. This pH paper is safe to use in medical applications.

[0038] Figure 7 depicts a capsule 110 of the first embodiment. The capsule 110 has an enteric coating and contains a dye tablet. For example, “Vegan Acid-Resistant (Enteric) Capsules” from CapsuleSupplies.com may be used. Enteric coatings resist dissolving in acidic environments. This enables the capsule 110 to predictably delay releasing the dye tablet into the solution 116 for a predetermined length of time. The time may be varied by altering the thickness of the capsules or by using multiple nested capsules of different sizes, like a Matryoshka doll. The following predetermined times for time alert reminders on bandages are contemplated: 12 hours, 24 hours, 48 hours, and 28 days. However, different predetermined times may be used. It is well known that enteric capsules have a delayed release in an acidic solution compared not non-enteric capsules.

[0039] A dye tablet, such as “PAAS® Egg Dye Tablets” (Signature Brands, LLC, Ocala, Florida) with a radius of 2 to 3mm, is contained in capsule 110. Larger or smaller dye tablets may be used, depending on the amount of solution 116 used. The PAAS® tablets contain the following ingredients: Sodium Bicarbonate, Maltodextrin, Magnesium Stearate, Cellulose Gum, and the following color options: FD&C Yellow 5, FD&C Red 40, FD&C Yellow 6, FD&C Blue 1, FD&C Red 3, FD&C Blue 2. Sodium Bicarbonate helps rapidly dissolve the dye tablet into the solution 116.

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SUBSTITUTE SHEET (RULE 26) [0040] Stickers with icons may be affixed to the sleeve 100 at locations aligned with the first and second windows 104 and 108 of the cover 102. A sticker with a white trashcan icon 112 is affixed to the sleeve 100 at the location aligned with the second window 108 in the cover 102. Before the solution 116 changes color, the lack of color around the trashcan icon 112 indicates that the predetermined length of time has not yet passed. When the solution 116 changes color, the colored solution 116 backlights the trashcan icon 112 to indicate that the predetermined length of time has passed. This provides a binary alert (unexpired, expired) to clearly indicate to a user when the predetermined length of time has passed. Using universally recognizable colors, such as green for unexpired and red for expired, and pictures, such as icons used on mobile devices, helps to clearly indicate either or both of the status and functions of the time alert reminder. The color changes rapidly to prevent user confusion. While a trashcan icon 112 is depicted, other similar communicative icons may be used to the same effect. These universally recognized images indicate “delete” or “empty” or “recycle” and thus aid comprehension by caregivers and patients. They transcend language, culture and literacy levels.

[0041] Optionally, a channel 118 may connect to the seal 117 on the bladder 114 and extend towards the capsule 110. The channel 118 restricts where the solution 116 may travel in the sleeve 100. When a user presses down on the bladder 114 to activate the time alert reminder, the solution 116 will be expelled through the channel 118, directly to the capsule 110. This reduces the amount of the solution 116 needed and causes the capsule 110 to dissolve more reliably. The channel 118 may be created by applying heat sealing the polyethylene material, although other methods may be used. The channel 118 may also be an added physical structure, such as a straw or flexible plastic ridges (sidewalls).

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SUBSTITUTE SHEET (RULE 26) [0042] Figure 8 depicts a 3-D hexagonal cage 120 that may be placed around the capsule

110 of the first embodiment to protect the capsule 110 from breaking and prematurely releasing the dye tablet. When the time alert reminder is used on a medical bandage, for example, the cage 120 prevents a patient from damaging the capsule 110 by lying on it. The cage 120 is made of a sturdy, plastic material and may be produced through 3-D printing. Other types of cages with different shapes or materials may be used.

[0043] The sleeve 100 may be adhesively applied to any object. As an additional safety feature, the adhesive may leave a stain or mark on an object when removed to indicate that the object was used.

[0044] The sleeve 100 may be manufactured in the following way. First, an opaque cover 102 is adhesively applied to one side of a plastic sheet. Icon stickers may be adhesively applied to the opaque cover from the inside. Second, the bladder 114, pH paper 106, and capsule 110 are adhesively applied to the other side of the plastic sheet. Third, the plastic sheet is folded onto itself to create a sleeve shape and is heat sealed to prevent the escape of its contents. Fourth, the plastic sheet may be further heat sealed to create the channel 118 within the sleeve 100. Fifth, icon stickers, such as the sticker with the trashcan icon 112, may be applied to the outside of the sleeve 100. If icon stickers are applied on the outside of the sleeve, a waterproof coating must be applied on top.

III. Patch with Litmus Paper Strips and Dissolvable Barrier

[0045] Figures 9-14 depict a second embodiment of a time alert reminder patch 200. A base layer 202 of the patch 200 has two strips of litmus paper 204 and 210 separated by a barrier 208. A bladder 206 is positioned above the first strip of litmus paper 204. The bladder 206 contains a neutral-pH solution, such as water, and is similar to the bladder 114 in the sleeve 100 of first

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SUBSTITUTE SHEET (RULE 26) embodiment. A transparent top layer 212 seals the patch 200. The base and top layers 202 and 212 of the patch 200 are made of a liquid-proof plastic material, such as polyethylene, and the barrier 208 is made of an organic substance (such as the material that makes up an enteric capsule, or sugar), which predictably dissolves in water.

[0046] The patch 200 is encased in an opaque cover. The cover has a first window 218 positioned over the bladder 206 and the first strip of litmus paper 204 and a second window 220 positioned over the second strip of litmus paper 210. High quality litmus paper should be used to produce more vivid colors. A sticker with a power icon 214 is placed on the top layer 212 at the location of the first window 218, and a sticker with a trashcan icon 216 is placed on the top layer 212 at the location of the second window 220. The power icon 214 indicates that a user should press at that location to activate the time alert reminder feature. Optimally, the power icon 214 is sized 10mm x 10mm to be easy for a user to press, and is the industry standard optimal size for mobile device finger swipes.

[0047] Figures 9 and 10 depict the patch 200 in its initial configuration. To activate the time alert reminder feature, a user presses down on the bladder 206, thereby rupturing the seal and expelling the solution into the first strip of litmus paper 204. The solution migrates through the first strip of litmus paper 204 to the barrier 208. The neutral-pH solution turns the first strip of litmus 204 paper green in color, which shows through the power icon 214 on the cover. Figures 11 and 12 depict the time alert reminder after the solution has been expelled onto the first strip of litmus 204 paper, but before the barrier 208 has dissolved. After a predetermined length of time, the solution dissolves the barrier 208, turning the solution slightly acidic, and allowing the solution to migrate through the second strip of litmus paper 210. The now-acidic solution turns the second strip of litmus paper 210 red in color. This backlights the trashcan icon 216, clearly indicating that

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SUBSTITUTE SHEET (RULE 26) the predetermined length of time has passed. Figures 13 and 14 depict the time alert reminder after the barrier 208 has dissolved and the solution has migrated through the second strip of litmus paper 210.

[0048] Like the sleeve 100 of the first embodiment, the patch 200 provides a binary (expired/nonexpired) alert, the color change occurs rapidly after the predetermined length of time passes, and the opaque cover hides the underlying process from the user to avoid confusion. The following predetermined times for time alert reminders on bandages are contemplated for all embodiments discussed herein: 12 hours, 24 hours, 48 hours, and 28 days. However, different predetermined times may be used. A user might select or purchase the alert with the predetermined time period that coincides with care instructions given by a medical provider.

[0049] Alternatively, solutions with different pH levels can be used to produce different color combinations. For example, using an alkaline solution will turn litmus paper blue.

[0050] The patch 200 may be adhesively applied to any object. As an additional safety feature, the adhesive may leave a stain or mark on an object when removed to indicate that the object was used.

IV. Multilayered Bandage

[0051] Figures 15-16 depict a third embodiment of a time alert reminder bandage 300. The bandage 300, which may have multiple layers, has a time-release color 302 printed on top or woven in. Importantly, the time-release color 302 is kept away from the bottom of the bandage 300, and therefore away from any wound.

[0052] As shown in Figure 15, a picture of a sad face 302 is printed on a bandage 300 using a time-release color. The sad face picture 302 is not yet visible. To prevent the time-release color 302 from activating right after being printed on the bandage 300, the place where the ink is applied

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SUBSTITUTE SHEET (RULE 26) on the bandage 300 may be hermetically sealed or covered with a removable coating sticker to prevent the start of the reaction.

[0053] The time-release color 302 used is an invisible ink. Gall ink is one well known type of invisible ink and consists of soluble polyphenols (typically gallic acid and a Fe(II) salt). As soon as the gall ink is applied a surface and exposed to air, the Fe(II) is oxidized to Fe(III), which forms insoluble, deep colors with the polyphenol. The permanent color may take about a day to develop. Although invisible ink is used as the time-release color in this embodiment, different time-release colors may be used to enable a wide variety of color changes, such as those that change color through chemical oxidation, enzyme oxidation, or exposure to enzymes or acidity (that may be present in a wound), mechanical pressure, heat, water or humidity, or a chemical spray.

[0054] The reaction may be started by unsealing the bandage 300 or removing the coating sticker. The time-release color 302 changes color or presents a colored mark to indicate the passage of a predetermined length of time. This is shown in Figure 16, where the time-release color is now fully colored, revealing the sad face picture 302. Unlike the first two embodiments, the color change is gradual and not binary. However, using universally understood colors and pictures, such as a red sad face, help to indicate to a user that the bandage 300 is expired.

[0055] Alternatively, the time-release color may be printed on a patch. The patch may be hermetically sealed or covered with a removable coating sticker to prevent the start of the reaction. The patch may then be adhesively applied to a bandage. The patch may be made from an industrial sticker, with adhesive paper and a mylar pull-off cover.

V. Embodiments are Not Limiting

[0056] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments

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SUBSTITUTE SHEET (RULE 26) disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims. Equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. For example, while an embodiment discussed above uses acid in a rupturable bladder to cause a delayed-release effect on an enteric capsule, it is equally within the spirit and scope of the invention to use a base solution to cause a delayed- release effect on a capsule with a coating that resists dissolution in a base environment.

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SUBSTITUTE SHEET (RULE 26)

Claims

CLAIMS We claim:

1. Apparatus for indicating when a predetermined time duration is over, comprising:

(a) a body;

(b) rupturable bladder within the body comprising a liquid;

(c) an indicator in the body that changes visible appearance in the presence of the liquid;

(d) a containment material surrounding a color dye, the containment material spaced in the body apart from but in fluid communication with the liquid after rupture of the rupturable bladder; wherein the containment material dissolves in the liquid after a predetermined time.

2. The apparatus of claim 1, wherein the liquid is an acid, and the containment material is an enteric capsule.

3. The apparatus of claim 2, wherein the liquid comprises citric acid.

4. The apparatus of claim 2, further comprising: a transparent surface over the bladder and the capsule, and an opaque surface over the transparent surface, the opaque surface comprising a first window over the bladder and a second window over the capsule.

5. The apparatus of claim 4, wherein the bladder further comprises self-clinging material surrounding a bladder volume, such that rupture of the bladder will preclude the bladder volume refilling with the liquid.

6. The apparatus of claim 4, wherein the bladder is adhesively fixed to an inner surface of the body.

7. The apparatus of claim 4, further comprising a rigid cage enclosing the capsule while not preventing passage of the liquid.

8. A system comprising the apparatus of claim 4 in physical combination with a medical bandage, whereby rupture of the bladder results in appearance of color after but not before

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SUBSTITUTE SHEET (RULE 26) a predetermined time in the second window, to indicate when it is time to change the bandage.

9. Apparatus for indicating when a predetermined time duration is over, comprising: a body; rupturable bladder within the body comprising a liquid; a first indicator in the body that changes visible appearance in the presence of the liquid; a dissolvable barrier in fluid communication with the liquid after rupture of the rupturable bladder; a second indicator in the body that changes visible appearance in the presence of the liquid, whereby the barrier dissolves in the liquid after a predetermined time after contact with the liquid, thus causing passage of the liquid, thus causing the second indicator to change color after dissolving of the barrier.

10. The apparatus of claim 9 wherein the dissolvable barrier comprises an enteric coating.

11. The apparatus of claim 9 wherein the liquid is neutral pH upon release from the rupturable bladder, but becomes acidic after dissolution of the dissolvable barrier.

12. The apparatus of claim 11 wherein the first indicator’s changed visible appearance is one color, and the second indicator’s changed visible appearance is a second color different from the one color.

13. The apparatus of claim 12, further comprising: a transparent surface over the first indicator and the second indicator, and an opaque surface over the transparent surface, the opaque surface comprising a first window over the first indicator and a second window over the second indicator.

14. The apparatus of claim 12, wherein the bladder further comprises self-clinging material surrounding a bladder volume, such that rupture of the bladder will preclude the bladder volume refilling with the liquid.

15. The apparatus of claim 12, wherein the bladder is adhesively fixed to an inner surface of the body.

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SUBSTITUTE SHEET (RULE 26) A system comprising the apparatus of claim 12 in physical combination with a medical bandage, whereby rupture of the bladder results in appearance of color in the second window after but not before a predetermined time has elapsed, to indicate when it is time to change the bandage. A bandage comprising a timing initiator and a delayed indicator, wherein the delayed indicator changes appearance rapidly and distinctly after a predetermined period of time after actuation of the timing initiator, whereby the bandage will indicate when enough time has elapsed that it needs to be changed.

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SUBSTITUTE SHEET (RULE 26)