Patent Description:
An infusion pump is a device attached to a wearer's body to deliver a medication continuously to a subcutaneous site on the wearer's body. A first type of infusion pump is suitable for a user with Type I diabetes, that is, a patient whose body does not produce native insulin. In this case, the insulin delivery process must be tightly controlled throughout the day, often in conjunction with frequent blood glucose testing, to ensure the user obtains the proper concentration of insulin in the bloodstream. For this purpose, a typical infusion pump system according to the prior art is a two part device which comprises a cannula-bearing infusion set worn on the body, and a programmable handheld controller module, which communicates wirelessly with the infusion set. A second type of infusion pump is purely disposable, intended for the Type II diabetes patient whose native insulin production and regulation is impaired and who prefers fewer features and less complexity than are provided with a Type I pump. The second type of pump is pre-programmed to deliver a continuous dose of insulin over a period of days, usually three-days. The user may have the option to fill the pump and to manually deliver meal time bolus injections with the same device, but this device is not provided with programming means to change the continuous dosage. In contrast, infusion pumps which are provided with programming means to change the continuous dosage are known from e.g. <CIT> and <CIT>, whereby <CIT> discloses a wearable medication infusion system according to the preamble of claim <NUM>.

Thus one object of the invention is to provide a disposable infusion pump that has selectable continuous rate dosage settings without requiring a wireless controller, and which provides simplified feedback in the form of an on-board display, so as to be suitable for a Type II diabetes patient desiring greater freedom in the processes of administering insulin.

The invention comprises a wearable medication infusion system as defined in claim <NUM>. Additional features of preferred embodiments of the invention are defined in the dependent claims. Thus, in one aspect, the invention pertains to a fluid medication delivery device comprising a wearable infusion pump. The pump contains a housing including an insertion cannula, a medication reservoir in communication with the cannula; an actuator in fluid communication with the reservoir and the cannula; an onboard display; a power source; and a microprocessor operatively communicating with the power source, the on-board display, the insertion cannula, and the actuator.

The infusion pump further includes a program key insert aperture in the housing and one or more program key(s) received in the program key insert aperture. Inserting the program key "wakes up" the device and closes one or more contacts on a printed circuit board within the housing to communicate a dosage rate to the microprocessor.

The illustrative embodiments of the invention refer to a wearable infusion pump in which the patient can insert a program key to enable a selectable, pre-set, continuous dosage rate, read real-time status and information from the device via an onboard display, and perform cannula insertion and bolus delivery operations via an onboard control. It is known to provide a wearable infusion pump for Type I diabetes with a handheld device with a wireless transmitter that needs to be programmed by the physician or patient in order to receive the medication dosage. Truly disposable pumps, as may be used to control Type II diabetes, are available for a single continuous dosage regimen. This means that a regimen of <NUM> insulin units per day, for example, requires a different set of pumps with a different stock keeping unit (SKU), than a set of pumps adapted to deliver <NUM> units per day.

In <FIG>, a wearable infusion pump drug delivery device <NUM> according to the invention is provided with housing <NUM> utilizing an onboard display <NUM>. The housing <NUM> provides the structure that supports the components of the infusion pump described below. The housing <NUM> is water-tight, preventing mechanical or electrical failure of the inner components resulting from fluid ingress. As the device is meant to be worn continuously on the body without removal for up to three days, the housing <NUM> is preferably composed of plastic or other lightweight material to prevent the device from becoming heavy or cumbersome on the user's body and includes an adhesive system (not shown) to adhere the device to the user's body.

In the embodiment of <FIG>, the onboard display <NUM> of device <NUM> has several light-emitting diodes (LEDs) indicating pump status and user prompts. In detail, LED <NUM> indicates the ON/OFF state of the infusion pump. The user turns the pump on by inserting the appropriate basal rate program key <NUM>-<NUM> in the program key insert aperture/key hole <NUM> located on the bottom, inferior portion of the pump housing <NUM>. The ON light diode then turns to green indicating a ready state after the user initially inserts the key. To avoid a continuously visible light display on the user's body, the green ON indicator may be adapted to dissipate after a period of time, as known in the art. After the device is switched on with the program key, the SET BASAL diode <NUM> flashes to green, indicating the microprocessor (MPU) <NUM> is reading and storing the basal rate programmed by the key (described in connection with <FIG>). After the basal rate is stored by the pump, a yellow LED on the FILL diode <NUM> prompts the user to fill reservoir <NUM> via a fill port <NUM> in fluid communication with the reservoir. The user fills reservoir <NUM> and the FILL diode <NUM> is lit with a green light, indicating the reservoir <NUM> is adequately filled with medication. Alternatively, the infusion pump may be adapted to accept a pre-filled cartridge with a similar system of prompts.

The disposable pump according to the invention typically can be worn for a period of up to three days. The reservoir <NUM> thus is capable of storing a volume of equivalent to the highest dose of medication given per day over three days, including meal-time bolus deliveries. The pump is adapted to provide continuous dosages of insulin in a range from <NUM> U/day to <NUM> U/day, preferably <NUM> U/day to <NUM> U/day. Mealtime bolus delivery generally does not exceed <NUM>-<NUM> U/day. Therefore, the reservoir <NUM> may hold up to <NUM>-<NUM> units of insulin, for example, according to the maximum amount of medication deliverable over a three-day period. The volume of the reservoir is not a critical feature, but based on this calculation could be <NUM> to <NUM>.

Any type of fluid delivery system known in the art may be used with the invention, such as a rotary pump in communication with a reservoir <NUM>, or a plunger <NUM> the like device within the reservoir, which provide pressure in response to actuator <NUM> to deliver a precise quantity of fluid to the cannula <NUM>. The actuator includes a motor <NUM> communicating with the microprocessor <NUM> to ensure that medication is delivered from the reservoir <NUM> in a calibrated amount.

Once the reservoir <NUM> is filled by the user, the medication is ready to be delivered through the cannula and inserted in the body. The device may comprise a motor <NUM> which inserts the cannula into the injection site responsive to a command from MPU <NUM>. The INSERT LED <NUM> then lights up, indicating the ready stage of the device to deliver medication to the user. At this point, the user can attach the device to the body using the adhesive. The cannula <NUM> is deployed by the user by depressing the INSERTION/BOLUS button <NUM>. The INSERTION/BOLUS <NUM> is a single, user-operable button attached to and sealed flush with the outer part of the housing <NUM> on the anterior portion, facing away from the user's body. It is depressed for two reasons. First, it is used for initial insertion of the cannula <NUM> into the user's body. The button also acts to provide a bolus delivery of drug, where the user activates a one-time bolus of medication, in addition to the continuous drug delivery, at mealtime for example, as is sometimes required for Type II diabetic patients. Although not limited in this regard, the INSERTION/BOLUS button <NUM> may be calibrated to deliver <NUM> to <NUM> units of insulin with each depression of the button, and would typically cut off after a maximum number of depressions, i.e., a maximum allowable daily bolus delivery may be pre-programmed into the MPU.

The cannula <NUM> is referred to herein as an "insertion cannula," meaning that the cannula is initially retracted into the housing and can be inserted into the user's subcutaneous space by pressing the INSERT/BOLUS button <NUM>. Apparatus for driving a small cannula of an infusion pump into a user's subcutaneous tissue are known in the art, and may be adapted from available designs. In embodiments, the cannula <NUM> is located on an infusion set connected to the infusion pump by tubing.

The STATUS <NUM> button of the onboard display <NUM> indicates to the user that the amount of insulin in the drug delivery device is low, or if an error condition is found. The STATUS <NUM> diode will light yellow when there is a low amount of insulin in the device and red when the reservoir <NUM> is at empty or if there is a device malfunction requiring action by the user.

<FIG> illustrates an embodiment of the device wherein the front side <NUM> of housing <NUM> is provided with the segmented or graphical display <NUM> alternative to the onboard LED display <NUM>. The segmented or graphical display <NUM> comprises a display of digitally generated alphanumeric characters. The display <NUM> indicates the same information as the onboard display <NUM> detailed above, however, using alphanumeric characters instead of LEDs. For example, the display <NUM> will flash the words "ON", "SET BASAL", "FILL", "INSERT", and "STATUS" to indicate the information available to the user regarding status of the device and user prompts. The use of the segmented or graphical on-pump display <NUM> constitutes an alternative embodiment to the LED onboard display <NUM>.

An important aspect of the present invention is illustrated in <FIG> which depict a program key insert aperture or "key hole" <NUM> which receives one of a plurality <NUM> of pre-programmed keys <NUM>-<NUM> each having a shape configured to close a predetermined number of contacts on printed circuit board (PCB) <NUM> which in turn communicates a predetermined instruction to microprocessor unit <NUM> to set the dosage. Using the pre-programmed keys allows the same pump to deliver different basal rates of insulin while at the same time avoiding the need for a complicated wireless programming device, which also reduces the likelihood of human error by eliminating the user calculation and programming steps characteristic of the prior art wireless devices.

<FIG> illustrates the bottom side <NUM> of the device where the program key insert aperture <NUM> is located. The bottom side of the housing <NUM> is sealed around the aperture <NUM> so that the device is water- and leak-proof. A flexible elastomeric material may be used for this purpose, sufficiently flexible to allow the program keys <NUM>-<NUM> to access the contacts on the PCB, but securely sealed against the opening. In embodiments, the microprocessor unit <NUM> is programmed to deliver a different dosage depending upon how many contacts are closed when the key is inserted, for example <NUM> units (U)/day, <NUM> U/day, <NUM> U/day up to <NUM> U/day. The contacts are depicted as extensions at different clock-hand positions extending radially from the perimeter of the key. Although many other configurations would be immediately apparent to those of ordinary skill in the art, this configuration is advantageous because a single stock keeping unit (SKU) is associated with the infusion pump capable of delivering different dosages depending on which key <NUM>-<NUM> is inserted, and the dosage programmed by the key is readily ascertained by the user simply by looking at the key, from its shape, and preferably also from its label and/or color.

The program keys are fashioned so that each different key closes a different number of contacts on the PCB. Each contact is connected to the microprocessor <NUM> through connecting traces <NUM>. The number of closed connections indicates what the set basal rate is and how many units to administer. Thus, <NUM> closed contacts from the program key <NUM> to the key hole <NUM> indicates <NUM> U/day; <NUM> closed contacts from the program key <NUM> to the key hole <NUM> indicates <NUM> U/day, etc. The microprocessor unit <NUM>, through connecting traces <NUM> on the PCB <NUM>, communicates with actuator <NUM>.

<FIG> schematically portrays the internal elements <NUM> of the infusion pump where the contacts on the PCB <NUM> communicate with the microprocessor unit <NUM>, which in turn communicates with the actuator <NUM>, and the display <NUM> all of which are mounted on printed circuit board <NUM>. The entire device is powered by an independent power source <NUM> housed in the device such as a battery or rechargeable battery.

In embodiments, the housing is provided with a single on-board user operable INSERTION/BOLUS button <NUM> for controlling cannula insertion and mealtime bolus delivery. The respective modes of the switch are dependent on the state of the device (i.e., the actuator cannot deliver a bolus unless the cannula has been inserted, and the cannula is only successfully inserted once). Alternatively, the device may be provided with separate insertion and bolus delivery buttons. After filling the reservoir, the user attaches infusion pump to the body, typically using an adhesive, and depresses the INSERTION/BOLUS <NUM> switch. Upon depression of the INSERTION/BOLUS <NUM> switch, the cannula <NUM> deploys from the housing <NUM> unit and breaks the user's skin. The cannula <NUM> then inserts into the subcutaneous layer of skin in order to deliver medication. The gauge of the cannula <NUM> must be such that it is small enough to be contained within the device and housing unit <NUM>, however, it must be large enough also to prevent breakage and to continuously deliver the medication to the user. Therefore, a cannula with needle gauge of <NUM>-<NUM> is preferable.

The end of the cannula <NUM> opposite the point of insertion is in fluid communication with the reservoir <NUM>. In embodiments, the reservoir <NUM> may be adapted to hold up to about <NUM> (<NUM> U), corresponding to a maximum dosage delivered over a three day period, including mealtime bolus delivery, but more typically up to about <NUM> (<NUM> U). In other embodiments, the pump is attached to an infusion set via tubing, so that the cannula is located on the infusion set.

The actuator <NUM> is also activated when the end-user pushes the INSERTION/BOLUS <NUM> button to deliver a one-time bolus of the drug. A preset amount of insulin is delivered each time the INSERTION/BOLUS button is depressed, such as <NUM> to <NUM> units, and typically <NUM>, <NUM> or <NUM> units of insulin per depression, up to a predetermined maximum per day.

As described above, the actuator <NUM> is controlled through the MPU <NUM> by the number of closed contacts activated in the program key insert aperture <NUM> by the program key. The MPU <NUM> also controls the onboard display <NUM> or segmented or graphical display <NUM>.

Claim 1:
A wearable medication infusion system, comprising:
an infusion set comprising an insertion cannula;
the infusion set connected by tubing to a wearable infusion pump (<NUM>),
said pump comprising a housing having an on-board display (<NUM>),
and within said housing
a medication reservoir (<NUM>) in fluid communication with the cannula;
an actuator (<NUM>) operatively communicating with the reservoir;
a power source; and
a microprocessor (<NUM>) operatively communicating with the power source, the on-board display, the insertion cannula and the actuator;
said infusion pump further comprising
a program key insert aperture (<NUM>) in the housing;
a program key (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) received in the program key insert aperture; and
a printed circuit board (<NUM>) having one or more contacts closed by the program key inserted in the program key insert aperture, operatively communicating with the microprocessor to set a dosage rate for the infusion pump,
further characterized in that a bottom side of the housing (<NUM>) is sealed around the key insert aperture (<NUM>) by a flexible elastomeric material to enable a water and leak proof pump, wherein the flexible elastomeric material has a sufficient flexibility to allow the program key (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to access the contacts on the printed circuit board (<NUM>) and securely seal the program key (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) against the key insert aperture (<NUM>);
and the microprocessor unit (<NUM>) is programmed to deliver a different dosage depending upon how many contacts are closed when the program key (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) is inserted, wherein the contacts of the program key (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) are extensions at different clock-hand positions extending radially from the perimeter of the program key (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>).