System and method for measuring rapid decompression ice nucleation in lyophilization
An environmental sensor system for monitoring nucleation in a lyophilization chamber is disclosed which includes a sensor unit, including a temperature sensor, a pressure sensor, and a reader circuit in electronic communication with the sensor unit; wherein the sensor unit is adapted to sealingly fit around a vial placed in a lyophilization chamber and further adapted to be energized by the reader circuit and provide signals associated with temperature and pressure within the vial in a non-invasive manner in which the sensors are configured to be positioned in a headspace within the vial but not in contact with product within the vial.
1 . An environmental sensor system for monitoring nucleation in a lyophilization chamber, comprising:
a sensor unit, including
a temperature sensor,
a pressure sensor; and
a reader circuit in electronic communication with the sensor unit;
wherein the sensor unit is adapted to sealingly fit around a vial placed in a lyophilization chamber and further adapted to be energized by the reader circuit and provide signals associated with temperature and pressure within the vial in a non-invasive manner in which the sensors are configured to be positioned in a headspace within the vial but not in contact with product within the vial.
2 . The environmental sensor system of claim 1 , further comprising a relative humidity (RH) sensor adapted to provide the RH of the headspace.
3 . The environmental sensor system of claim 2 , wherein the signals associated with temperature, pressure and RH are communicated wirelessly to a base station.
4 . The environmental sensor system of claim 3 , wherein the wireless protocol is selected from the group consisting of Bluetooth Low Energy (BLE), WiFi, ZigBee®, Z-Wave®, Thread®, and cellular.
5 . The environmental sensor system of claim 1 , wherein temperature, and relative humidity readings from the environmental sensor are used to calculate the dew point of product within the vial according to:
D
P
=
λ
(
ln
(
R
H
1
0
0
+
β
T
λ
+
T
)
β
-
(
ln
(
RH
/
100
+
βT
/
(
λ
+
T
)
)
where RH is the relative humidity,
T is the temperature,
α=6.112 hPa (hectopascal),
β=17.62° C., and
λ=243.12° C.
6 . A system for determining onset of nucleation in a lyophilization chamber, comprising:
a lyophilization chamber;
at least one vial containing a product to be lyophilized,
at least one sensor unit coupled to each of the at least one vials, adapted to measure a corresponding temperature, pressure, and relative humidity (RH);
at least one pressure sensor adapted to provide absolute pressure within the lyophilization chamber;
a processor adapted to receive signals from the at least one sensor unit, the processor configured to calculate the dew point of each of the at least one vials, and
based on temperature of each of the at least one vials determine if onset of nucleation has occurred.
7 . The system of claim 6 , wherein the dew point is calculated based on:
D
P
=
λ
(
ln
(
R
H
1
0
0
+
β
T
λ
+
T
)
β
-
(
ln
(
RH
/
100
+
βT
/
(
λ
+
T
)
)
where RH is the relative humidity,
T is the temperature,
α=6.112 hPa (hectopascal),
β=17.62° C., and
λ=243.12° C.
8 . The system of claim 6 , wherein the signals from the at least one sensor unit is received by the processor in a wireless manner.
9 . The system of claim 6 , wherein the wireless protocol is selected from the group consisting of Bluetooth Low Energy (BLE), WiFi, ZigBee®, Z-Wave®, Thread®, and cellular.
10 . A method of determining onset of nucleation in a lyophilization chamber, comprising:
receiving a signal corresponding to headspace parameters from at least one sensor unit coupled to each of a corresponding vials in a lyophilization chamber, adapted to measure corresponding temperature, pressure, and relative humidity (RH) in the headspace; and
receiving a signal corresponding to absolute pressure from at least one pressure sensor receiving absolute pressure within the lyophilization chamber from a pressure sensor disposed therein;
a processor calculating the dew point of each of the at least one vials, and
based on temperature of each of the at least one vials determining if onset of nucleation has occurred.
11 . The method of claim 10 , wherein the dew point is calculated based on:
D
P
=
λ
(
ln
(
R
H
1
0
0
+
β
T
λ
+
T
)
β
-
(
ln
(
RH
/
100
+
βT
/
(
λ
+
T
)
)
where RH is the relative humidity,
T is the temperature,
α=6.112 hPa (hectopascal),
β=17.62° C., and
λ=243.12° C.
12 . The method of claim 10 , the signal corresponding to headspace parameters from the at least one sensor unit is received in a wireless manner.
13 . The system of claim 12 , wherein the wireless protocol is selected from the group consisting of Bluetooth Low Energy (BLE), WiFi, ZigBee®, Z-Wave®, Thread®, and cellular.