Drug delivery device and method
First Claim
1. In a drug delivery device having a pressurized source of a liquid medicament delivering the liquid drug to an outlet via a flow path, the flow path including a flow restriction and first and second valves, a method for identifying the presence of a gas bubble in the flow path, the method comprising:
- (a) operating the first and second valves in such a manner as to ensure a pressure between the first and second valves significantly below a pressure of the pressurized source;
(b) during a pressure accumulation period, maintaining the first valve open and the second valve closed; and
(c) at the end of the pressure accumulation period, identifying the presence or absence of a gas bubble in the flow path based at least in part on a measurement of pressure between the first and second valves.
1 Assignment
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Accused Products
Abstract
A drug delivery device includes a pressurized reservoir in communication with a flow path to an outlet. The flow path includes two normally-closed valves and a flow restriction. A pressure measurement arrangement measures a differential fluid pressure between two points along the flow path which span at least part of the flow restriction, one of the points being between the valves. A controller selectively opens the valves to deliver a defined quantity of the liquid medicament to the outlet.
94 Citations
12 Claims
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1. In a drug delivery device having a pressurized source of a liquid medicament delivering the liquid drug to an outlet via a flow path, the flow path including a flow restriction and first and second valves, a method for identifying the presence of a gas bubble in the flow path, the method comprising:
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(a) operating the first and second valves in such a manner as to ensure a pressure between the first and second valves significantly below a pressure of the pressurized source; (b) during a pressure accumulation period, maintaining the first valve open and the second valve closed; and (c) at the end of the pressure accumulation period, identifying the presence or absence of a gas bubble in the flow path based at least in part on a measurement of pressure between the first and second valves. - View Dependent Claims (2, 3)
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4. In a drug delivery device having a pressurized source of a liquid drug delivering the liquid drug to an outlet via a flow path, the flow path including a flow restriction, a method for identifying the presence of a gas bubble in the flow path, the method comprising:
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(a) monitoring at least one parameter affected by a pressure drop across the flow restriction; and (b) when the at least one parameter satisfies a bubble-detection condition indicative of a reduced pressure drop across the flow restriction, indicating the presence of a gas bubble in the flow path. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12)
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Specification