Fig 4. In vitro evaluation of adherence IVR.

Response of adherence IVR over 100 h using a simulated insertion/removal cycle of 2.5 h in and 0.5 h out (lower plot) using a programmed temperature test apparatus. Data represent the IN/OUT status (0 or 1) logged at a 5 min interval. The upper plot shows expansion of data at 6, 48, and, 96 h for three adherence IVRs measuring simultaneously. Vertical dotted lines indicate transition to “IN” temperature for each cycle shown. The temporal alignment of “IN” measurements does not vary between the three devices over 96 h of measurement. The time required for the device to respond to a simulated insertion or removal event was determined using the temperature-time data shown in Fig 5. The device was exposed to three repeated step changes in temperature between 28°C and 37°C, and response was calculated as the time required for the device to measure the range of 10% to 90% of the total 9°C temperature change (28.9°C and 36.1°C). For the step from 28°C to 37°C (simulated insertion), the 10%-90% time was 1.84 ± 0.006 min. For the step from 37°C to 28°C (simulated removal), the 90% to 10% time was 1.96 ± 0.096 min.