Becton Dickinson and Company Limited

Vyteris, Inc.

Kenneth E Garde

Ronald J Flower

Steven D Walter

Circuits are provided for increasing the reliability of an iontophoretic drug delivery system. Such circuits detect the failure of a crystal oscillator of the system, the failure of a voltage reference of the system, or the impending failure of a battery power source of the system.

Circuits for increasing the reliability of an iontophoretic system

An iontophoretic drug delivery device includes a controller normally being in an off or low power consumption state, and a patch including electrodes, a reservoir for holding an ionizable drug for transdermal delivery to a patient and a return reservoir. The patch is removable and electrically connectable to the controller, and delivers the drug to patient when the patch is on the patient's skin and when the controller is switched from the off or low power consumption state to an operational state. This occurs when the patch is connected to the controller and a connector connects a power source to the controller or an activation means signals the controller to switch to the operational state. This feature preserves the battery of the controller.

Devices activating an iontophoretic delivery device

A circuit for causing a voltage step in a battery of a plurality of serially-connected cells is provided. The circuit causes one or more of the cells to discharge through a resistor at a higher rate than the other cells, thus producing a voltage step when the faster discharging cell dies before the other cells. A reverse-biased diode is connected in parallel to the faster discharging cell to cause the current to bypass the faster discharging cell after it has died, thus preventing it from reverse charging. This circuit may be controlled to adjust the higher rate of discharge, and thus the time of occurrence of the voltage step.

Circuit for causing a voltage step in a multi-cell battery

A fail-safe iontophoretic drug delivery apparatus and a corresponding method is provided. The apparatus includes a current generating circuit for sending a current through a patch, error detection circuitry, and a control circuit. The control circuit controls the current generating circuit. When errors are detected in the apparatus, the control circuit stops the current and disables itself.

Circuit and method for automatically turning off an iontophoresis system

An iontophoretic drug delivery system of the present invention includes a controller interconnectable with a drug-filled patch. The controller includes electronic circuitry which monitors and controls the supply of electrical current to the drug-filled patch during delivery of at least one drug, and the electronic circuitry includes a circuit for causing a voltage step in a battery of a plurality of serially-connected cells. Specifically, the circuit causes one or more of the cells to discharge through a resistor at a higher rate than the other cells, thus producing a voltage step when the faster discharging cell dies before the other cells. A reverse-biased diode is connected in parallel to the faster discharging cell to cause the current to bypass the faster discharging cell after it has died, thus preventing it from reverse charging. This circuitry may be controlled to adjust the higher rate of discharge, and thus the time of occurrence of the voltage step.

Iontophoretic drug delivery system

A iontophoretic drug delivery apparatus and a corresponding method is provided. The apparatus includes a switched-capacitor DC--DC voltage converter to step up a supply voltage, and a current control circuit that draws current from the stepped-up voltage.

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New Windsor, NY, United States of America

Kenneth E Garde