Apparatus, system and method for measuring resistance of an inhaler

1. A closed-loop system for measuring the resistance of an inhaler comprising:

an apparatus comprising a first chamber having a first valve and a second chamber having a second valve,

wherein the first chamber and the second chamber are sealably attached to one another to form a barrier to ambient air and

wherein the first and second chambers communicate with one another via an air pathway established by an inhaler air conduit located between the first chamber and the second chamber;

a vacuum pump attached to the first chamber configured to maintain constant pressure; and

one or more microprocessors configured to detect and analyze pressure differential signals from the first and the second chamber and a signal for a flow rate through the inhaler;

wherein the one or more microprocessors analyze the signals using a closed-loop algorithm based on the pressure and flow rate signals.

2. The closed-loop system of claim 1 , further comprising at least one flow controller and at least one pressure sensor.

3. The closed-loop system of claim 1 , wherein the pressure and flow rate measurements are made by a flow controller of the closed-loop system at predetermined pressure drop settings for the inhaler.

4. The closed-loop system of claim 1 , further comprising a flow controller.

5. The closed-loop system of claim 4 , wherein the flow controller comprises a microprocessor, a laminar flow sensor, a valve and a pressure sensor.

6. The closed-loop system of claim 4 , wherein the flow controller is attached to the second chamber.

7. The closed-loop system of claim 1 , wherein the closed-loop system further comprises a pressure controller.

8. The closed-loop system of claim 7 , wherein the pressure controller is attached to the first chamber.

9. The closed-loop system of claim 1 , wherein the at least one microprocessor is configured to control opening and closing of the first and second valves.

10. The closed-loop system of claim 1 , wherein the inhaler is held in place so as to not be moveable when the first and second chambers are sealably attached to one another.

11. A method for measuring the resistance to airflow of an inhaler, comprising:

attaching a first chamber having a first valve to a second chamber having a second valve,

wherein the first and second chambers are sealably attached to each other to form a barrier to ambient air, and

wherein the first and second chambers communicate with each other via an air pathway established by an inhaler air conduit located between the first chamber and the second chamber;

obtaining a constant pressure environment in the first chamber by using a vacuum pump attached to the first chamber;

controlling opening and closing of the first and second valves by using at least one microprocessor;

simultaneously measuring:

a flow rate though the inhaler air conduit and

a pressure differential between the first and second chambers; and

analyzing the signals using a closed-loop algorithm.

12. The method of claim 11 , wherein the constant pressure environment is maintained by a closed-loop algorithm.

13. The method of claim 11 , wherein the flow rate and pressure differential measurements from various test set points of the inhaler are analyzed with an algorithm to generate a resistance value for the inhaler.

14. The method of claim 13 , wherein the resistance value for the inhaler is determined using pressure differential measurements.

15. The method of claim 11 , wherein the pressure and flow rate measurements are made at predetermined pressure drop settings for the inhaler.

16. The method of claim 11 , wherein at least three predetermined value settings are used to measure pressure differential and flow rate and determine the resistance value of the inhaler.