A kit for monitoring the volume of fluid in a receptacle

Abstract

A kit for monitoring the volume of fluid in a receptacle (1) for collection of bodily waste, such as an ostomy bag. The kit comprises at least one detectable substance (12) for adding to a receptacle (1) before the receptacle is used to collect fluid. The kit further has a probe (4) to be located at least partially within the receptacle. The probe (4) can detect when the detectable substance has been diluted by fluid in the receptacle. As the detectable substance is diluted as the receptacle fills with bodily waste, the probe can detect when the bag is full or nearing full. The kit further has a controller (6) for the probe, the controller (6) being capable of processing data from the probe and triggering an alert to the wearer.

Description

A KIT FOR MONITORING THE VOLUME OF FLUID IN A RECEPTACLEField of the Invention

[0001] The invention relates to receptacles for bodily waste, such as an ostomy bag or exterior collection device and systems and methods for determining the volume of fluid in a receptacle.Background

[0002] Colorectal conditions such as inflammatory bowel disease, trauma, diverticular disease, and malignancy can require surgical intervention and intestinal diversion through the creation of a stoma. The latter is a surgical opening on the abdomen through which the passage of faeces is directed into an external disposable pouch. It has been estimated that there are between 175,000 and 205,000 ostomates (ileostomy, colostomy and urostomy) in the UK, with over 20,000 new stomas created each year. While there have been substantial advances in surgical procedures, complications post release remain considerable and can impact on psychological and physiological wellbeing. The creation of a diverting ileostomy can be particularly problematic where the intestinal surface area for reabsorption can be greatly reduced thereby leading to a high stomal output. Where there is persistent loss of large amounts of small bowel fluid (1500-2000 mL I 24 h), dehydration and electrolyte disorders can arise and are a common factor in the readmission of patients with an ileostomy. High output stomas (HOS) can also greatly increase the propensity towards pouch leakage and peristomal skin complications. Moisture associated skin damage through prolonged exposure to the bowel fluid can be particularly troublesome for patients as it can directly impact on the subsequent adhesion of the collection pouch to the skin.

[0003] Measuring stoma output is critical in the early stages of recovery from surgery where there is a need to monitor fluid balance but also for those whose stoma starts to increase output either because of diet, disease or injury. Determining the volume of stoma output is presently done using a measuring jug and either visual approximation or weight. One known solution marketed as the Ostomi-I Alert Sensor™, by 11 HealthTechnologies Limited, involves clipping a flexible band on the outside of the ostomy bag. As the bag fills the flexible band is stretched. Data regarding the flexible band and thus the volume of the ostomy bag is relayed wirelessly to the wearer. With this product, the flexible band will be distorted as the ostomy bag moves about when the wearer moves, thereby affecting the accuracy of the readings. At present, to the best of our knowledge, there are no other technological solutions for stoma patients. The use of a jug is problematic in terms of accuracy and the inconvenience and becomes impractical when the patient is returning to employment.

[0004] The present invention seeks to obviate or mitigate the problems outlined above. Specifically, the present invention seeks to obviate or mitigate the problems associated with determining stoma output.Summary of the Invention

[0005] According to a first aspect of the invention there is provided a kit for monitoring the volume of fluid in a receptacle for collection of bodily waste, wherein the kit comprises at least one detectable substance for adding to a receptacle before the receptacle is used to collect fluid, the kit further comprising a probe to be located at least partially within the receptacle for detecting when the detectable substance has been diluted by fluid in the receptacle.

[0006] Optionally, the detectable substance is a biocompatible substance.

[0007] Optionally, the detectable substance is an electrolyte, nutrient, metabolite, biomarker, peptide, antibody, enzyme, nucleic acid, hormone, neurotransmitter, or antioxidant.

[0008] Optionally, the detectable substance is a purine-related metabolite, vitamin, heterocyclic nitrogen compound or combinations thereof.

[0009] Optionally, the detectable substance is riboflavin, uric acid, xanthine, hypoxanthine, or combinations thereof.

[0010] Optionally, the kit comprises 1 mg to 1 g of the detectable substance.

[0011] Optionally, the probe determines the concentration of the detectable substance when a threshold quantity of fluid has entered the receptacle.

[0012] Optionally, the threshold quantity of fluid is at least 1 ml.

[0013] Optionally, the probe is an electrochemical probe and comprises at least two electrodes, further wherein the probe is connected to a controller for determining the current between the at least two electrodes.

[0014] Optionally, the controller is further capable of adjusting the potential difference between the at least two electrodes.

[0015] Optionally, the probe is connected to the controller by an electrically conductive wire.

[0016] Optionally, the controller has an attachment means for releasable attachment to a wearer. The attachment means may comprise a belt or loop attached to the controller and extendable around a wearer’s waist. The attachment means may comprise one or more hook and loop type fasteners to attach the controller to a wearer.

[0017] Optionally, the controller comprises a processor for determining when there has been an increase in fluid volume in the receptacle, or determining when the fluid volume in the receptacle approaches a predetermined level, or both.

[0018] Optionally, the processor is further capable of converting the signal detected by the probe into a volume value, or receptacle fullness value.

[0019] Optionally, the controller further comprises a transmitter for transmitting data derived from or regarding the signal detected by the probe.

[0020] Optionally, the detectable substance may be disposed on the probe and insertable into a receptacle together with the probe.

[0021] Optionally, the detectable substance may be adsorbed onto a receptacle surface.

[0022] Optionally, the probe can detect two or more different detectable substances. Optionally, the probe can detect three or more different detectable substances. Optionally, the probe can detect four or more different detectable substances.

[0023] Optionally, the kit comprises a first detectable substance, and a second detectable substance, wherein the second detectable substance is different to the first detectable substance. Optionally, the kit further comprises a third detectable substance, and wherein the third detectable substance is different to the first and second detectable substances. Optionally, the kit further comprises a fourth detectable substance, and wherein the fourth detectable substance is different to the first, second and third detectable substances.

[0024] Optionally, the kit comprises a first probe for detecting a first detectable substance, and a second probe for detecting a second detectable substance, and wherein the second detectable substance is different to the first detectable substance. Optionally, the kit further comprises a third probe for detecting a third detectable substance, and wherein the third detectable substance is different to the first and second detectable substances. Optionally, the kit further comprises a fourth probe for detecting a fourth detectable substance, and wherein the fourth detectable substance is different to the first, second and third substances.

[0025] Optionally, the detectable substances each have distinct electrochemical signatures.

[0026] According to a second aspect of the invention there is provided a receptacle for collection of bodily waste, wherein the receptacle comprises at least one detectable substance that is added to the receptacle before the receptacle is used to collect fluid, the receptacle comprising a probe for detecting when the detectable substance has been diluted.

[0027] Optionally, the detectable substance is a biocompatible substance.

[0028] Optionally, the detectable substance is an electrolyte, metabolite, biomarker, peptide, antibody, enzyme, nucleic acid, hormone, neurotransmitter, or antioxidant.

[0029] Optionally, the detectable substance is a purine-related metabolite, vitamin, heterocyclic nitrogen compound or combinations thereof.

[0030] Optionally, the detectable substance is riboflavin, uric acid, xanthine, hypoxanthine, or combinations thereof.

[0031] Optionally, the receptacle contains 1 mg to 1 g of the detectable substance.

[0032] Optionally, the concentration of the detectable substance is 0.001 to 1% (w / v) when 100 ml of fluid is present in the receptacle.

[0033] Optionally, the probe determines the concentration of the detectable substance when a threshold quantity of fluid has entered the receptacle.

[0034] Optionally, the threshold quantity of fluid is at least 1 ml.

[0035] Optionally, the probe can detect two or more different detectable substances. Optionally, the probe can detect three or more different detectable substances. Optionally, the probe can detect four or more different detectable substances.

[0036] Optionally, the receptacle comprises a first detectable substance, and a second detectable substance, wherein the second detectable substance is different to the first detectable substance. Optionally, the receptacle further comprises a third detectable substance, and wherein the third detectable substance is different to the first and second detectable substances. Optionally, the receptacle further comprises a fourth detectable substance, and wherein the fourth detectable substance is different to the first, second and third detectable substances.

[0037] Optionally, the receptacle comprises a first probe for detecting a first detectable substance, and a second probe for detecting a second detectable substance, and wherein the second detectable substance is different to the first detectable substance. Optionally, the receptacle further comprises a third probe for detecting a third detectable substance, and wherein the third detectable substance is different to the first and second detectable substances. Optionally, the receptacle further comprises a fourth probe for detecting a fourth detectable substance, and wherein the fourth detectable substance is different to the first, second and third substances.

[0038] Optionally, the detectable substances each have distinct electrochemical signatures.

[0039] Optionally, the probe is an electrochemical probe. Optionally, the probe comprises at least two electrodes. Optionally, the probe is connected to a controller for determining the current between at least two electrodes.

[0040] Optionally, the controller is capable of measuring the potential difference between the at least two electrodes.

[0041] Optionally, the controller is capable of adjusting the potential difference between the at least two electrodes.

[0042] Optionally, the probe is connected to the controller by an electrically conductive wire.

[0043] Optionally, the controller has an attachment means for releasable attachment to a wearer. The attachment means may comprise a belt or loop attached to the controller and extendable around a wearer’s waist. The attachment means may comprise one or more hook and loop type fasteners to attach the controller to a wearer.

[0044] Optionally, the controller comprises a processor for determining when there has been an increase in fluid volume in the receptacle, or determining when the fluid volume in the receptacle approaches a predetermined level, or both.

[0045] Optionally, the processor is further capable of converting the signal detected by the probe into a volume value, or receptacle fullness value.

[0046] Optionally, the controller further comprises a transmitter for transmitting data derived from or regarding the signal detected by the probe, or both.

[0047] Optionally, the probe is located at least partially within the receptacle.

[0048] Optionally, the receptacle further comprises a drain, and wherein the probe is located at least partially within the drain.

[0049] Optionally, the receptacle is an ostomy bag or external collection device.

[0050] Optionally, the ostomy bag comprises a base plate, and optionally the probe is integrated into the base plate.

[0051] Optionally, the receptacle further comprises a skin barrier.

[0052] Optionally, the receptacle further com prises a barrier opening, engageable with a stoma.

[0053] Optionally, the receptacle has a maximum volume of 200 to 2000 ml. Optionally, the receptacle has a maximum volume of 500 to 1500 ml. Optionally, the receptacle has a maximum volume of 1000 ml or around 1000 ml.

[0054] The receptacle may comprise the kit according to the first aspect of the invention, or any features thereof.

[0055] According to a third aspect of the invention there is provided a method for modifying a receptacle to enable the volume of fluid in the receptacle to be determined, the method comprising the steps of: a. providing a receptacle; b. inserting a detectable substance into the receptacle; and, c. inserting a probe into the receptacle.

[0056] Optionally, step b) may involve inserting the detectable substance by disposing the detectable substance on the probe initially, and then inserting the probe and detectable substance together into the receptacle. Alternatively, or additionally, step b) may involve adsorbing the detectable substance onto the receptacle surface.

[0057] Optionally, step c) may involve inserting the probe by integrating the probe into a base plate of the receptacle.

[0058] Optionally, the method involves inserting the probe into the drain of the receptacle.

[0059] Optionally, the method involves wired or wirelessly connecting the probe to a controller.

[0060] The method may involve using the kit according to the first aspect of the invention.

[0061] The receptacle, detectable substance and probe may have any of the features of the receptacle, detectable substance and probe as described in relation to any other aspect of the invention.

[0062] According to a fourth aspect of the invention there is provided a method for determining when the volume of fluid in the receptacle of the second aspect of the invention has increased, the method comprising the steps of:a. using the probe to determine a first current between two electrodes of the probe at a set potential difference; b. using the probe to determine a second current between two electrodes of the probe at the same potential difference; c. calculating if the second current is lower than the first current; and d. confirming that the volume of fluid has increased if the second current is lower than the first current.

[0063] Optionally, the method involves confirming that the volume of the fluid has increased if the second current is lower than the first current by at least 10%.

[0064] In step c) the calculating may be conducted by subtracting the second current from the first current. If the resulting value is a positive number, then the second current is lower than the first current.

[0065] Optionally, step d) involves alerting a user by an audible or visual alert. Optionally, step d) involves transmitting data to an external device, such as a smartphone or tablet, which then alerts a user. Optionally, the step involves transmitting data from the controller.

[0066] The receptacle and probe may have any of the features of the receptacle or probe described in relation to any other aspect of the invention.List of Figures

[0067] Specific implementations of the present disclosure will now be described, by way of example only, and with reference to the accompanying drawings in which:

[0068] Figure 1 shows voltammograms highlighting the response of the probe towards a detectable substance where the fluid volume is low (A) and high (B).

[0069] Figure 2 shows a schematic of a stoma pouch according to the present disclosure.

[0070] Figure 3 is a block diagram of the probe and controller according to the present disclosure.

[0071] Figure 4 is a squarewave voltammogram detailing the probe response to uric acid under simulated conditions. The graph inset is corresponding calibration data from which concentration can be determined.

[0072] Figure 5 is a squarewave voltammogram detailing the probe response to xanthine under simulated conditions. The graph inset is corresponding calibration data from which concentration can be determined.

[0073] Figure 6 is a squarewave voltammogram detailing the probe response to hypoxanthine under simulated conditions. The graph inset is corresponding calibration data from which concentration can be determined.

[0074] Figure 7 is a squarewave voltammogram comparing the peak positions of three purine metabolites - providing clear resolution between the three metabolites and highlighting the potential for multiparametric detection - providing multiple handles through which to calculate concentration in a complex medium. This allows the molecular probe which is added to the sensor / pouch to be “tuned” to avoid interference form endogenous compounds.Detailed Description

[0075] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently described subject matter pertains. The meaning and scope of these terms should be clear, but in cases of ambiguity, the definitions articulated herein supersede any definitions found in dictionaries or external sources.

[0076] Within the specification and the appended claims, unless explicitly stated otherwise, the ensuing terms are ascribed the meanings outlined: The term “biocompatible” means a substance not harmful to humans.

[0077] The term “bodily waste” means excretory products from a human or animal such as urine or faeces or both.

[0078] The term “current” means an electrical current. An electrical current is a flow of charged particles, such as electrons or ions, moving through an electrical conductoror space. In the context of the probe, the current between the two electrodes will be a measure of the flow of charged particles between the two electrodes.

[0079] The term “detectable substance” means any substance detectable by a probe.

[0080] The term “probe” in reference to the probe of the receptacle means a device configured to detect the detectable substance in a fluid. In particular, the probe can detect the detectable substance in fluid in the receptacle. The detection may be as a result of a change in the current between electrodes of the probe. The probe need not necessarily detect only the detectable substance and may detect multiple substances which affect the change in current between the electrodes.

[0081] The term “electrically conductive wire” means a flexible length of metal for carrying electric current. The metal may be copper, for example, and it may be coated by an insulator, such as thermoplastic or thermoset materials (e.g. polyvinyl chloride, polyethylene, etc).

[0082] The term “electrochemical probe” means a device comprising at least two electrodes and being capable of gathering chemical information based on the interaction between a substance and the electrode. Electrochemical probes may also have three electrodes for use of cyclic or squarewave voltammetry.

[0083] The term “external collection device” is a device for collecting bodily waste and includes an external urine collection device.

[0084] The term “fluid” means a liquid or gas. In the context of the present disclosure, fluid includes bodily waste, for example, urine, faeces, or both.

[0085] The term “processor” means an electronic circuit capable of performing calculations and computational tasks.

[0086] The term “ostomy bag” means a device attachable to a wearer to collect waste through a stoma on the wearer. Ostomy bags are also known as an ostomy pouch, stoma bag, or stoma pouch.

[0087] The term “receiver” means an electronic device capable of acquiring signals from a transmitter.

[0088] The term “receptacle” means a container for fluid, such as a bag formed from flexible material and non-permeable material. The receptacle may be formed at least in part from polymeric material such as a polyolefin. Suitable materials include polymers comprising ethylene-vinyl acetate.

[0089] The term “stoma” means an opening in a person’s abdomen that is connected to a digestive or urinary system to allow waste to pass from the digestive or urinary system and out the opening.

[0090] The term “transmitter” means an electronic device capable of sending signals to a receiver.

[0091] The term “vitamin” means an organic compound essential to an organism for proper metabolic function.

[0092] In the figures there is shown a receptacle 1 according to the present invention for collection of bodily waste 2. The receptacle 1 contains at least one detectable substance 12. The detectable substance may be provided as a known quantity of a detectable substance. The detectable substance is added to the receptacle 1 before the receptacle 1 is used in the collection of bodily waste. The receptacle 1 further comprises a probe 4 for determining when the detectable substance has been diluted. The detectable substance will become diluted when fluid enters the receptacle, for example, from a stoma when in use. Thus, by detecting when the substance is diluted, the probe can determine when the volume of fluid in the receptacle 1 has increased. This can be used to trigger an alarm to a wearer of the receptacle 1 to alert the wearer that the receptacle 1 is nearing full or is full.

[0093] In the illustrated example, the detectable substance is riboflavin, also known as vitamin B2. Alternatively, the detectable substance may be other biocompatible substances, such as an electrolyte, metabolite, biomarker, peptide, antibody, enzyme, nucleic acid, hormone, neurotransmitter, or antioxidant. The detectable substance may be uric acid, xanthine or hypoxanthine. Combinations of the preceding substances may also be used.

[0094] The probe 4 is an electrochemical probe and comprises at least two electrodes 5. The probe 4 is connected to a controller 6 for determining the electrical current between the two electrodes 5. The electrodes may be formed from carbon (graphiterod, glassy carbon, boron doped diamond, carbon fibre, screen printed carbon), graphene, graphene oxide or laser induced graphene, carbon composites (carbon mixed with a polymeric or epoxy binder or conductive filaments, such as those used in 3D printers, for example carbon black and PLA-based filaments), or gold such as gold wire or screen-printed gold.

[0095] The controller 6 is further capable of adjusting the potential difference between the electrodes 5. As such, the controller 6 can adjust the current between the electrodes 6. The controller 6 comprises a potentiostat 8, enabling it to adjust the potential difference between the electrodes 5 and to determine the current between the electrodes 5. The controller 6 may have a cyclic voltametric, squarewave voltametric, or amperometric operational mode, wherein the controller 6 controls the potential difference between the electrodes 5. Additionally, or alternatively, the controller 6 may have a potentiometric operational mode, wherein the controller 6 measures the potential difference between the two electrodes 5 but does not control the potential difference between the two electrodes 5.

[0096] The probe 4 is connected to the controller 6 by an electrically conductive wire 7. The controller 6 further has an attachment means for releasable attachment to a wearer.

[0097] The controller 6 comprises a processor 9. The processor can determine when there has been an increase in fluid volume in the receptacle 1 . More specifically, the processor 9 can determine when the current between the two electrodes 5 of the probe 4 at a set potential difference decreases and can trigger an alert upon determining the decrease. The drop in current is indicative of an increase in fluid volume level because the concentration of the detectable substance has decreased as it is diluted by the fluid volume. This results in a reduction in current between the two electrodes at a given potential difference. The controller 6 and processor 9 can be configured to trigger an alert when the current drops by more than 10%, for example.

[0098] In some embodiments, the processor 9 is configured to convert the current data to a concentration of the detectable substance 12. The processor 9 may be further be configured to convert the current data or concentration data into a volume of fluid in the receptacle 1 , or a percentage fullness value.

[0099] The controller 6 further comprises a transmitter 13 for transmitting data derived from or regarding the signal detected by the probe. The data may be transmitted to a receiving device, such as a smartphone or tablet. The receiving device may then raise an alert, such as an audible or visual alert, or both, to alarm the wearer of the receptacle 1 that the fluid volume has reached a certain level. This can be useful to alert the wearer when the receptacle is full or approaching fullness, as the wearer can then take steps to empty the receptacle 1.

[0100] The controller 6 comprises a power source 11 , which may be a battery, or a rechargeable battery, for example. The power source 11 powers the processor 9, potentiostat 8 and transmitter 13.

[0101] In a further embodiment, not shown, the controller is capable of raising an alert to the wearer. In this embodiment, the controller may comprise a speaker, vibrating unit, light emitting means, or electronic display, for example, or combinations thereof, to provide an alert. In this embodiment, the transmitter is not necessary, but could be included so that an alert may be raised at the controller but also in a connected device that receives the signal from the transmitter.

[0102] In the illustrated embodiment, the probe 4 is located at least partially within the receptacle 1. More specifically, the receptacle has a drain 14, and the probe 4 is located at least partially within the drain 14. In the illustrated embodiment, the receptacle 1 is an ostomy bag 15. In other embodiments not shown, the receptacle may be an external collection device other than an ostomy bag, or other device for collecting bodily waste fluids. The ostomy bag 15 has a skin barrier and a barrier opening 16 that is engageable with a stoma.

[0103] In one embodiment, not shown, the receptacle is an ostomy bag that comprises a base plate. In this embodiment, the probe is integrated into the base plate.

[0104] The receptacle 1 has a maximum volume of 1000 ml. In other embodiments, the maximum volume may be varied. For example, overnight ostomy bags may have a greater volume than 1000 ml.

[0105] The amount of the detectable substance present in the receptacle may be a value within the following ranges: 1 mg to 10 g, 5 mg to 5 g, or 1 mg to 1 g. Any lower limit from the preceding ranges may be combined with any of the upper limits.

[0106] The amount of the detectable substance present in the receptacle may be a value within the following ranges: 25 pmol to 100 mmol, 50 pmol to 10 mmol, or 100 pmol to 1 mmol. Any lower limit from the preceding ranges may be combined with any of the upper limits.

[0107] The concentration of the detectable substance may be a value within the following ranges when 100 ml of fluid is present in the receptacle: 0.001 to 10% (w / v), 0.005 to 5% (w / v), or 0.01 to 1% (w / v). Any lower limit from the preceding ranges may be combined with any of the upper limits.

[0108] The concentration of the detectable substance may be a value within the following ranges when 200 ml of fluid is present in the receptacle: 0.0005 to 5% (w / v), 0.0025 to 2.5% (w / v), or 0.005 to 0.5% (w / v). Any lower limit from the preceding ranges may be combined with any of the upper limits.

[0109] The concentration of the detectable substance may be a value within the following ranges when fluid is present in the receptacle: 25 pM to 100 mM, 50 pM to 10 mM, or 100 pM to 1 mM. Any lower limit from the preceding ranges may be combined with any of the upper limits.

[0110] The probe 4 determines the concentration of the detectable substance when a threshold quantity of fluid has entered the receptacle 1. The threshold quantity of fluid is the lowest amount of fluid required to cover the electrodes, and by as low as 2 or 3 ml. The threshold quantity of fluid is at least 1 ml. The controller 6 can be configured to trigger an alarm when the detectable substance has been diluted by 100-fold, 200- fold or 300-fold. The dilution is determined by a proportional drop in current at a set potential difference as determined by the probe.

[0111] In use, it is possible to determine when the volume of fluid in the receptacle 1 has increased, using the following steps: a. using the probe 4 to determine a first current between two electrodes 5 of the probe at a set potential difference; b. using the probe 4 to determine a second current between two electrodes 5 of the probe at the same potential difference; c. calculating if the second current is lower than the first current; andd. confirming that the volume of fluid has increased if the second current is lower than the first current.

[0112] The current between the electrodes 5 is at an initial high level as a result of the presence of the detectable substance. As the fluid volume in the receptacle 1 increases, the detectable substance becomes diluted, and the current between the electrodes 5 resultingly decreases. The potentiostat 8 is set to maintain a constant potential difference between the electrodes 5. The potentiostat 8 is further capable of determining the current between the electrodes 5. The potentiostat 8 provides data regarding the current to the processor 9. The processor 9 is configured to determine when the current drops below a certain value. For example, the processor 9 may be configured to confirm that the volume of the fluid has increased if the second current is lower than the first current by at least 10%.

[0113] A user or wearer can be alerted by an audible or visual alert, or both, when the current has decreased beyond a certain predetermined value. The processor 9 determines when the current has decreased beyond the predetermined value, and then triggers the transmitter 13 to transmit a signal to a receiver, such as a smartphone or tablet. The receiver then initiates an alarm. An alarm may be provided also or alternatively by the controller 6 itself, wherein the processor may be configured to directly trigger an alarm.

[0114] Figure 4 presents a squarewave voltammogram detailing the probe 4 response to uric acid under simulated conditions. Uric acid, a common metabolite and byproduct of DNA / purine catabolism, exhibits a distinct electrochemical signature, as shown in the voltammogram. The current observed can be used to determine the metabolite concentration, which correlates with fluid volume. The inset graph provides corresponding calibration data, enabling the calculation of concentration from the peak current.

[0115] Figure 5 illustrates a squarewave voltammogram of the probe 4 response to xanthine under simulated conditions. Xanthine, another biocompatible metabolite, displays its unique electrochemical signature. The inset graph contains calibration data, facilitating the determination of concentration based on the voltammetric profile.

[0116] Figure 6 is a squarewave voltammogram showing the probe 4 response to hypoxanthine under simulated conditions. Hypoxanthine, similar to uric acid and xanthine, is a metabolite with a significant electrochemical signature. The distinct peak current, as highlighted in the voltammogram, serves as a marker for hypoxanthine concentration, which can be used for the accurate determination of fluid volume. Calibration data presented in the inset graph further supports the quantification process.

[0117] Figure 7 provides a comparative squarewave voltammogram illustrating the peak positions of uric acid, xanthine, and hypoxanthine, showcasing clear resolution between the three metabolites. This figure demonstrates the potential for multiparametric detection, allowing for multiple markers to be used in calculating concentration within a complex medium like stoma fluid. The markedly different peak positions of these metabolites provide a safeguard against potential interference from endogenous compounds in stoma fluid, as it is unlikely that an interfering molecule would affect all three markers simultaneously. This enhances the reliability of the measurement process.

[0118] The data presented in Figures 4-7 highlight the importance of selecting biocompatible metabolites such as uric acid, xanthine, and hypoxanthine, whose electrochemical signatures are distinct and intense. This distinction is particularly advantageous in complex mediums like stoma fluid, where endogenous compounds might otherwise interfere with the signal. The use of multiple probes and careful choice of biomarkers provide a method to verify the "true" response, minimising the chances of false signals.

[0119] Moreover, while Figures 4-7 specifically demonstrate voltammetric profiles, it is important to note that other electrochemical methodologies can also be employed. These methodologies operate on the principle that a change in concentration of a marker, due to dilution within the pouch, can be monitored electrochemically. This versatility in techniques ensures robust and accurate monitoring of fluid volume.

[0120] Where a range of values is provided, for example, concentration ranges, percentage ranges, or ratio ranges, it is understood that each intervening value, to the tenth of the unit of the lower limit, unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or interveningvalue in that stated range, is encompassed within the described subject matter. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and such embodiments are also encompassed within the described subject matter, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the described subject matter.

[0121] It should be understood that the terms "a" and "an" as used above and elsewhere herein refer to "one or more" of the enumerated components. It will be clear to one of ordinary skill in the art that the use of the singular includes the plural unless specifically stated otherwise. Therefore, the terms “a,” “an” and “at least one” are used interchangeably in this application.

[0122] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as size, weight, reaction conditions and so forth used in the specification and claims are to the understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present subject matter. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0123] Throughout the application, descriptions of various embodiments use "comprising" language; however, it will be understood by one of skill in the art, that in some instances, an embodiment can alternatively be described using the language "consisting essentially of or "consisting of."

Claims

CLAIMS1. A kit for monitoring the volume of fluid in a receptacle for collection of bodily waste, wherein the kit comprises at least one detectable substance for adding to a receptacle before the receptacle is used to collect fluid, the kit further comprising a probe to be located at least partially within the receptacle for detecting when the detectable substance has been diluted by fluid in the receptacle.

2. The kit of claim 1 wherein the detectable substance is a biocompatible substance.

3. The kit of claim 1 or claim 2 wherein the detectable substance is an electrolyte, nutrient, metabolite, biomarker, peptide, antibody, enzyme, nucleic acid, hormone, neurotransmitter, or antioxidant.

4. The kit of claim 3 wherein the detectable substance is a purine-related metabolite, vitamin, heterocyclic nitrogen compound or combinations thereof.

5. The kit of claim 4 wherein the detectable substance is riboflavin, uric acid, xanthine, hypoxanthine, or combinations thereof.

6. The kit of any preceding claim comprising 1 mg to 1 g of the detectable substance.

7. The kit of any preceding claim wherein the probe determines the concentration of the detectable substance when a threshold quantity of fluid has entered the receptacle.

8. The kit as claimed in claim 7 wherein the threshold quantity of fluid is at least 1 ml.

9. The kit of any preceding claim wherein the probe is an electrochemical probe and comprises at least two electrodes, further wherein the probe is connected to a controller for determining the current between the at least two electrodes.

10. The kit of claim 9 wherein the controller is further capable of adjusting the potential difference between the at least two electrodes.

11. The kit of claim 9 or claim 10 wherein the probe is connected to the controller by an electrically conductive wire.

12. The kit of any one of claims 9 to 11 wherein the controller has an attachment means for releasable attachment to a wearer.

13. The kit of any of claims 9 to 12 wherein the controller comprises a processor for determining when there has been an increase in fluid volume in the receptacle, or determining when the fluid volume in the receptacle approaches a predetermined level, or both.

14. The kit of claim 13 wherein the processor is further capable of converting the signal detected by the probe into a volume value, or receptacle fullness value.

15. The kit of claim 14 wherein the controller further comprises a transmitter for transmitting data derived from or regarding the signal detected by the probe.

16. The kit of any preceding wherein the probe can detect two or more different detectable substances.

17. The kit of any preceding claim wherein the probe can detect three or more different detectable substances.

18. The kit of any preceding claim wherein the probe can detect four or more different detectable substances.

19. The kit of any preceding claim comprising a first detectable substance, and a second detectable substance, wherein the second detectable substance is different to the first detectable substance.

20. The kit of claim 19 further comprising a third detectable substance, and wherein the third detectable substance is different to the first and second detectable substances.

21. The kit of claim 20 comprising a fourth detectable substance, and wherein the fourth detectable substance is different to the first, second and third detectable substances.

22. The kit of claim 19 comprising a first probe for detecting the first detectable substance, and a second probe for detecting the second detectable substance.

23. The kit of any claim 20 comprising a first probe for detecting the first detectable substance, a second probe for detecting the second detectable substance, and a third probe for detecting the third detectable substance.

24. The kit of claim 21 comprising a first probe for detecting the first detectable substance, a second probe for detecting the second detectable substance, a third probe for detecting the third detectable substance, and a fourth probe for detecting the fourth detectable substance.

25. The kit of any one of claims 19 to 25 wherein the detectable substances each have distinct electrochemical signatures.

26. A receptacle for collection of bodily waste, wherein the receptacle comprises at least one detectable substance that is added to the receptacle before the receptacle is used to collect fluid, the receptacle further comprising a probe to for detecting when the detectable substance has been diluted by fluid in the receptacle.

27. The receptacle of claim 26 wherein the concentration of the detectable substance is 0.001 to 1% (w / v) when 100 ml of fluid is present in the receptacle.

28. The receptacle of any preceding claim wherein the probe is located at least partially within the receptacle.

29. The receptacle of claim 28 further comprising a drain, and wherein the probe is located at least partially within the drain.

30. The receptacle of any preceding claim wherein the receptacle is an ostomy bag or external collection device.

31. The receptacle of claim 30 wherein the ostomy bag comprises a base plate, and wherein the probe is integrated into the base plate.

32. The receptacle of claim 31 further comprising a skin barrier, and a barrier opening, engageable with a stoma.

33. The receptacle of any preceding claim wherein the receptacle has a maximum volume of 200 to 2000 ml.

34. A method for modifying a receptacle to enable the volume of fluid in the receptacle to be determined, the method comprising the steps of: a. providing a receptacle; b. inserting a detectable substance into the receptacle; and, c. inserting a probe into the receptacle.

35. A method for determining when the volume of fluid in the receptacle of any preceding claim has increased, the method comprising the steps of: a. using the probe to determine a first current between two electrodes of the probe at a set potential difference; b. using the probe to determine a second current between two electrodes of the probe at the same potential difference; c. calculating if the second current is lower than the first current; and d. confirming that the volume of fluid has increased if the second current is lower than the first current.

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