Glucose sensor calibration
First Claim
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1. A process for calibrating a glucose sensor in a sterile environment, the glucose sensor comprising a sensing probe for detecting glucose, the process comprising:
- (i) providing a calibration unit comprising (a) at least a first and a second sterile calibration fluid, each calibration fluid having a different concentration of glucose, (b) a sensing zone, a sensing region of the sensing probe of the glucose sensor being located within the sensing zone, wherein the sensing region of the sensing probe is surrounded by a membrane, and (c) a waste chamber for collecting used calibration fluid;
(ii) providing the first calibration fluid to the sensing zone such that the fluid is in contact with the sensing region, and determining a sensor output;
(iii) flushing the first calibration fluid to the waste chamber;
(iv) providing the second calibration fluid to the sensing zone such that the fluid is in contact with the sensing region, and determining the sensor output; and
(v) using the sensor output readings to calibrate the glucose sensor;
wherein the calibration process is carried out under sterile conditions, and wherein said glucose sensor is an invasive fiber optic glucose sensor containing a fluorescent glucose indicator system, the sensor probe being adapted to detect glucose in vivo.
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Abstract
A process for calibrating a glucose sensor under sterile conditions includes providing separate, sterile, glucose-containing calibration fluids, each having a different glucose concentration, and in turn providing these fluids to a sensing zone containing a sensing probe of a glucose sensor. Each solution is typically, in turn, propelled into the sensing zone, thus flushing out used fluid already present in the sensing zone. The process provides rapid calibration of a glucose sensor in a sterile fashion and is therefore appropriate for point-of-use calibration.
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Citations
24 Claims
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1. A process for calibrating a glucose sensor in a sterile environment, the glucose sensor comprising a sensing probe for detecting glucose, the process comprising:
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(i) providing a calibration unit comprising (a) at least a first and a second sterile calibration fluid, each calibration fluid having a different concentration of glucose, (b) a sensing zone, a sensing region of the sensing probe of the glucose sensor being located within the sensing zone, wherein the sensing region of the sensing probe is surrounded by a membrane, and (c) a waste chamber for collecting used calibration fluid; (ii) providing the first calibration fluid to the sensing zone such that the fluid is in contact with the sensing region, and determining a sensor output; (iii) flushing the first calibration fluid to the waste chamber; (iv) providing the second calibration fluid to the sensing zone such that the fluid is in contact with the sensing region, and determining the sensor output; and (v) using the sensor output readings to calibrate the glucose sensor; wherein the calibration process is carried out under sterile conditions, and wherein said glucose sensor is an invasive fiber optic glucose sensor containing a fluorescent glucose indicator system, the sensor probe being adapted to detect glucose in vivo. - View Dependent Claims (2, 3, 4, 5, 6, 24)
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7. A glucose sensor kit comprising a sensing probe for detecting glucose and a calibration unit, wherein the calibration unit comprises:
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a sensing zone having at least one inlet and at least one outlet, a sensing region of the sensing probe being located in the sensing zone, wherein the sensing region of the sensing probe is surrounded by a membrane; a first calibration chamber containing a first sterile calibration fluid, the first calibration chamber being connected to, or adapted for connection to, an inlet to the sensing zone; a second calibration chamber containing a second sterile calibration fluid having a glucose concentration different from that of the first calibration fluid, the second calibration chamber being connected to, or adapted for connection to, an inlet to the sensing zone; at least one fluid propulsion means for propelling calibration fluid from the calibration chambers to the sensing zone; a waste chamber configured to collect used calibration fluid which is flushed out of the sensing zone; the glucose sensor kit configured to carry out calibration of a sensor under sterile conditions, and wherein the sensing probe is part of an invasive fiber optic glucose sensor containing a fluorescent glucose indicator system, and the sensor probe is adapted to detect glucose in vivo. - View Dependent Claims (8, 9, 10, 11)
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12. A calibration unit for calibrating an invasive fiber optic glucose sensor, said sensor containing a fluorescent glucose indicator system and a sensor probe being adapted to detect glucose in vivo, wherein said calibration unit comprises:
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a sensing zone having at least one inlet and at least one outlet, the sensing zone configured to house a sensing region of a sensing probe of the glucose sensor, wherein the sensing region of the sensing probe is surrounded by a membrane; a first calibration chamber containing a first sterile calibration fluid, the first calibration chamber being connected to, or adapted for connection to, the at least one inlet to the sensing zone; a second calibration chamber containing a second sterile calibration fluid having a glucose concentration different from that of the first calibration fluid, the second calibration chamber being connected to, or adapted for connection to, the at least one inlet to the sensing zone; at least one fluid propulsion means for propelling calibration fluid from the calibration chambers to the sensing zone; and a waste chamber configured to collect used calibration fluid which is flushed out of the sensing zone; the calibration unit being configured to carry out calibration of the sensor under sterile conditions. - View Dependent Claims (13, 14, 15)
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16. A process for the preparation of a calibration unit for calibrating a glucose sensor, comprising the steps:
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(i) providing glucose in solid form in a first mixing chamber, and water or an aqueous solution in a second mixing chamber; (ii) sterilizing the first and second mixing chambers by use of heat or irradiation; (iii) mixing contents of the first and second chambers to provide a first, sterile glucose-containing calibration fluid; (iv) providing at least a portion of the first calibration fluid to a first calibration chamber, whilst maintaining sterility of the fluid; (v) providing at least one further sterile calibration fluid, each further fluid having a glucose concentration different from one another and from the first calibration fluid, the further calibration fluid(s) being provided in one or more further calibration chambers; (vi) connecting the first and one or more further calibration chambers to a calibration unit such that the calibration chambers are connected to, or adapted for connection to, an inlet to a sensing zone of the calibration unit; and (vii) sterilizing the calibration unit using a surface sterilant, said sterilizing step using the surface sterilant being carried out either before or after step (vi), to provide said sterile calibration unit containing said first calibration fluid as a part of at least two sterile calibration fluids. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification