Dose measurement system and method
Embodiments described herein generally relate to devices, systems and methods for measuring the dose remaining in a drug delivery device that is used for delivering a dose to a patient. In some embodiments, a dose measurement system for measuring the liquid volume in a container includes a plurality of light sources which are disposed and configured to emit electromagnetic radiation toward the container. A plurality of sensors are located in the apparatus that are optically coupleable to the plurality of light sources and are disposed and configured to detect the electromagnetic radiation emitted by at least a portion of the light sources. The apparatus also includes a processing unit configured to receive data representing the portion of the detected electromagnetic radiation from each of the plurality of sensors. The processing unit is further operable to convert the received data into a signature representative of the electromagnetic radiation detected by the plurality of sensors.
1. An apparatus for measuring liquid volume in a container, the apparatus comprising:
a plurality of light sources disposed and configured to emit electromagnetic radiation toward the container;
a plurality of sensors optically coupleable to the plurality of light sources, each sensor of the plurality of sensors disposed and configured to detect the electromagnetic radiation emitted by at least two of the plurality of light sources; and
a processing unit configured to receive data representative of the detected electromagnetic radiation from each of the plurality of sensors, the processing unit operable to combine the received data into a signal signature representative of the electromagnetic radiation detected by the plurality of sensors.
2. The apparatus of claim 1 , wherein the processing unit is further configured to associate the signal signature with a reference signature, the reference signature being representative of a liquid volume in the container.
3. The apparatus of claim 1 , wherein the plurality of light sources, the plurality of sensors and the processing unit are disposed in a housing, the housing configured to be removably coupleable to a drug delivery device.
4. The apparatus of claim 3 , wherein the drug delivery device is an injection pen.
5. The apparatus of claim 4 , wherein the housing is a pen cap.
6. The apparatus of claim 5 , wherein at least one of the injection pen and the pen cap includes alignment features configured to allow the pen cap to be coupled to the injection pen in a predetermined radial orientation.
7. The apparatus of claim 1 , wherein the processing unit includes a memory configured to temporarily store at least one of the data representative of the detected electromagnetic radiation from each of the plurality of sensors and the signal signature representative of the electromagnetic radiation detected by the plurality of sensors.
8. The apparatus of claim 1 , wherein the processing unit includes a memory configured to store a plurality of reference signatures, each of the plurality of reference signatures being representative of a liquid volume in the container.
9. The apparatus of claim 1 , wherein the processing unit includes an RFID chip configured to store information, the REID chip configured to allow a near field communication-enabled device to read the stored information.
10. The apparatus of claim 1 , wherein the light sources are light emitting diodes.
11. The apparatus of claim 1 , wherein the sensors are photodetectors.
12. The apparatus of claim 1 , wherein the electromagnetic radiation is infrared radiation.
13. The apparatus of claim 1 , wherein the electromagnetic radiation is microwave radiation.
14. The apparatus of claim 1 , wherein the electromagnetic radiation is emitted in pulses.
15. A method of estimating a volume of liquid in a drug container, the method comprising:
causing a plurality of light sources to emit electromagnetic radiation toward the drug container;
detecting the electromagnetic radiation emitted by at least two of the plurality of light sources with each of a plurality of sensors;
combining data representative of the detected electromagnetic radiation from each of the plurality of sensors into a signal signature representative of the electromagnetic radiation detected through the drug container by the plurality of sensors; and
comparing the signal signature to a plurality of reference signatures to determine the volume of liquid in the drug container.
16. The method of claim 15 , further comprising:
calculating a dose delivered to a patient based on the volume of liquid in the container.
17. The method of claim 15 , further comprising:
correcting the signal signature for background light.
18. A method, comprising:
causing a plurality of light sources to emit electromagnetic radiation toward an injection pen a first time;
detecting the electromagnetic radiation emitted by at least two of the plurality of light sources with each of a plurality of sensors at the first time;
combining data representative of the detected electromagnetic radiation from each of the plurality of sensors to obtain a first signal signature of the electromagnetic radiation detected through the injection pen by the plurality of sensors;
comparing the first signal signature to a plurality of reference signatures to determine a first volume of liquid in the injection pen;
causing the plurality of light sources to emit electromagnetic radiation toward the injection pen a second time after the first time;
detecting the electromagnetic radiation emitted by at least two of the plurality of light sources with each of the plurality of sensors at the second time;
combining data representative of the detected electromagnetic radiation from each of the plurality of sensors to obtain a second signal signature of the electromagnetic radiation detected through the injection pen by the plurality of sensors;
comparing the second signal signature to the plurality of reference signatures to determine a second volume of liquid in the injection pen; and
estimating a dose delivered from the injection pen based on the first volume and the second volume.
19. The method of claim 18 , wherein the plurality of light sources and the plurality of sensors are disposed in an injection pen cap removably coupleable to the injection pen, the method further comprising:
obtaining the first signal signature at the first time when the injection pen cap is coupled to the injection pen; and
obtaining the second signal signature at the second time when the injection pen cap is recoupled to the injection pen after being removed at least once from the injection pen after the first time.
20. The method of claim 18 , further comprising:
communicating information associated with the dose delivered to an external device.
21. The apparatus of claim 1 , wherein each of the plurality of sensors is disposed and configured to detect at least one of a transmitted portion, a refracted portion, and a reflected portion of the electromagnetic radiation.
22. The apparatus of claim 1 , further comprising:
a communications module configured to allow two-way communication between the apparatus and a remote device.
23. The apparatus of claim 1 , further comprising:
an insulation structure configured to shield electronic components of the apparatus from external electromagnetic noise.
24. The apparatus of claim 1 , further comprising:
a display configured to communicate information associated with a status of the apparatus to a user.
25. The apparatus of claim 24 , wherein that status includes at least one of a number of doses remaining, a history of use, remaining battery life, wireless connectivity, a user reminder, and a user alert that liquid volume in the container is critically low.
26. The method of claim 15 , further comprising:
generating the plurality of reference signatures by recording a signal signature for each of a range of dose volumes in the drug container.
27. The method of claim 17 , wherein correcting the signal signature for background light includes comparing the signal signature with a background signature detected by the plurality of sensors in a dark state of each of the plurality of light sources.