US 12,420,011 B2
Devices and methods for flow restriction in a microfluidic circuit for drug delivery
Robert Farra, Action, MA (US)
Assigned to Cequr SA, Horw (CH)
Appl. No. 16/964,360
Filed by Cequr SA, Horw (CH)
PCT Filed Feb. 15, 2019, PCT No. PCT/IB2019/000150
§ 371(c)(1), (2) Date Jul. 23, 2020,
PCT Pub. No. WO2019/158997, PCT Pub. Date Aug. 22, 2019.
Claims priority of provisional application 62/631,522, filed on Feb. 16, 2018.
Prior Publication US 2021/0030952 A1, Feb. 4, 2021
Int. Cl. A61M 5/168 (2006.01); A61K 38/28 (2006.01); A61M 5/142 (2006.01); A61M 5/152 (2006.01)
CPC A61M 5/16804 (2013.01) [A61K 38/28 (2013.01); A61M 5/14248 (2013.01); A61M 5/152 (2013.01); A61M 2205/0244 (2013.01); A61M 2205/3331 (2013.01); A61M 2205/7545 (2013.01); A61M 2207/00 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A device for administering a liquid drug formulation to a patient, the device comprising:
a reservoir configured to hold a quantity of the liquid drug formulation; and
a microfluidic circuit which comprises at least one flow path configured to transport the liquid drug formulation from the reservoir to a drug release outlet,
wherein the at least one flow path comprises a pressure sensor disposed between a first flow restrictor comprising a first flow channel having an inlet and a second flow restrictor comprising a second flow channel having an outlet in the at least one flow path, wherein each of the first flow restrictor and the second flow restrictor is not a microcapillary, and wherein each of the inlet and the outlet are tapered,
wherein the pressure sensor, the first flow restrictor, and the second flow restrictor are disposed in a first substrate such that each of the first flow channel and second flow channel have a closed, elongated bottom wall, an elongated opening in a planar surface of the first substrate opposed to the bottom wall, and a pair of elongated sidewalls extending between the bottom wall of the flow channel and the elongated opening, the elongated opening closed off by a second substrate, and
wherein the pressure sensor comprises (i) a pressure chamber formed into the first substrate and disposed between the first flow channel and the second flow channel, (ii) a pressure dome adjacent to the pressure chamber and disposed between the first flow restrictor and the second flow restrictor, the pressure dome comprising a first region of the second substrate that is thinner than each of a second region of the second substrate that covers the first flow channel and a third region of the second substrate that covers the second flow channel, and (iii) a strain gauge disposed about the pressure dome.