ANALYTE-CONTROLLED LIQUID DELIVERY DEVICE AND ANALYTE MONITOR

摘要

A liquid delivery device (40) comprising a housing (41) having a lower surface (51) for application to the skin of a subject and having a reservoir (42) and a gas generation chamber (43) therein separated by a displaceable membrane (45). Gas generated by an electrolytic cell (44) under the control of a microprocessor (46) causes the gas generation chamber (43) to expand and the reservoir (42) to contract, thereby discharging a liquid drug, such as insulin, from the reservoir via a hollow delivery needle (49) extending from the lower surface (51). The delivery needle (49) and a sensor needle (48) both extend from the lower surface a sufficient distance so as to penetrate through the epidermis and into the dermis when the housing is pressed against the skin. The sensor needle (48) has an enzymatic coating for the detection of an analyte, such as glucose in the subject's plasma. The delivery needle (49) is made of platinum-iridium, and a current passes between the needles (48, 49) and a potentiostat circuit (47) according to the amount of glucose detected. A reference electrode (silver/silver chloride) (50) which rests against the subject's skin increases the accuracy of the glucose measurement. The current through the potentiostat circuit (47) is measured by a voltmeter (53) and a signal from the voltmeter (53) is amplified and communicated to the microprocessor (46) which determines the correct rate of delivery of the drug on the basis of the level of analyte detected in the subject's plasma.