Self-test for analgesic product
Electrotransport drug delivery devices, system and methods of using configured to determine if a current is present between the anode and cathode when drug is not intended to be delivered by the device. These devices/systems may include an off-current module to determine that any current (e.g., which may be inferred by measuring potential difference between the anode and cathode of the device) flowing between the anode and cathode is below a threshold value when the device is not supposed to be delivering drug, thereby preventing unintended delivery of drug and/or alerting a user that unintended delivery of drug may occur.
1. An electrotransport drug delivery device that prevents unwanted delivery of drug while in an off state when the device is powered on, the device comprising:
an anode;
a cathode;
an activation circuit configured to apply current between the anode and cathode to deliver a drug by electrotransport when the device is in an on state and not in the off state; and
an off-current module, the module configured to automatically and periodically determine if there is a current flowing between the anode and cathode when the activation circuit is in the off state while powered on.
2. The device of claim 1 , wherein the off-current module comprises control logic.
3. The device of claim 1 , wherein the off-current module comprises firmware, software and/or hardware configured to determine if there is a potential difference between the anode and the cathode when the activation circuit is in the off state while powered on.
4. The device of claim 1 , wherein the off-current module comprises software, firmware and/or hardware configured to determine if there is a change in capacitance between the anode and cathode when the activation circuit is in the off state while powered on.
5. The device of claim 1 , wherein the off-current module comprises software, firmware and/or hardware configured to determine if there is a change in inductance between the anode and cathode when the activation circuit is in the off state while powered on.
6. The device of claim 1 , wherein the off-current module comprises a sensing circuit that independently determines an anode voltage and a cathode voltage and compares the potential difference between the anode voltage and cathode voltage to a threshold value.
7. The device of claim 6 , further including a switch connected between a reference voltage source and a sense resistor, the off-current module configured to close the switch periodically to determine the potential difference between the anode voltage and cathode voltage.
8. The device of claim 1 , wherein the off-current module is configured to determine if there is a current flowing between the anode and cathode when the activation circuit is in the off state at least once per minute.
9. The device of claim 1 , wherein the off-current module is configured to determine if there is a current flowing between the anode and cathode when the activation circuit is in the off state between at least once every 10 ms and once every 10 minutes.
10. The device of claim 1 , wherein the off-current module is configured to wait at least 10 ms before determining if there is a current flowing between the anode and cathode when the activation circuit is in the off state.
11. The device of claim 1 , wherein the device has a two-part structure comprising:
an electrical module including the activation circuit and the off-current module; and
a reservoir module including the anode and the cathode and a source of drug to be delivered;
wherein the electrical module and reservoir module are configured to be combined prior to application to a patient.
12. The device of claim 11 , wherein the off-current module is not enabled until the electrical module and reservoir module are combined.
13. The device of claim 1 , wherein the off-current module is configured to indicate that there is a current flowing between the anode and cathode when the activation circuit is in the off state while powered on where the current flowing is above an Output Current Off Threshold.
14. The device of claim 13 , wherein the Output Current Off Threshold is about 9 μA.
15. The device of claim 1 , further comprising an Rsense resistor and an Rsense accuracy module configured to verify the accuracy of an Rsense resistance value.
16. The device of claim 1 , further comprising an anode/cathode voltage difference test that measures the anode voltage and the cathode voltage using the ADC and calculates the voltage difference between the two.
17. An electrotransport drug delivery device that prevents unwanted delivery of drug while in an off state, the device comprising:
a reservoir module including: an anode, a cathode and a source of drug;
an electrical module including:
an activation circuit configured to apply current between the anode and cathode to deliver a drug by electrotransport when the device is in an on state and not in the off state; and
an off-current module, the module configured to automatically and periodically determine if there is a current flowing between the anode and the cathode greater than an Output Current Off Threshold of 9 μA when the activation circuit is in the off state while powered on;
wherein the reservoir module and the electrical module are configured to be combined before being applied to a patient.