Team Members: Joe Bothwell Communicator Kelly ToyTeam Leader Jon Cappel BWIG Karim Mahamud BSAC

Client: Jack Jiang, M.D., PhD Division of Otolaryngology UW Medical School Advisor: John Webster, Ph. D Biomedical Engineering

A device to atomize medication (water) molecules to sizes ranging from 5 to 20 µm. This is most easily achieved by modifying existing jet nebulizers to create particle sizes to our specification. ABSTRACT

PROBLEM STATEMENT The goal of this project is to develop a device that can selectively produce liquid particles in the range of 5 to 20 µm. This device should safely and accurately produce the particles with precision of  10% to the desired mean.

Background There is a lot of research available on spray technology Most medical atomization devices are designed to target the lower respiratory system. Particle size affects the location of distribution, particles smaller than 5 µm tend to bypass the larynx.

MOTIVATION Available devices tend to be quite complex, and expensive. It would be ideal to select a specific particle size to analyze the different effects it has on the larynx. Conduct research to determine which way to atomize particles is the best.

Product Design Specification Dispense liquid (water) particles of sizes ranging from 5-20 µm Portable Simple design, easy to use. Reliable to ± 10% for 6 months or 400 uses Adaptable as an inhaler to channel medication directly to patient. Should be ergonomically pleasing to patients

Variables effecting Particle Size A larger orifice creates larger particle sizes. Higher pressure creates smaller particle sizes. Large Orifice Small Orifice

Design Alternatives Modification of Salter Labs Nebulizer Modification of Pari LC Plus Nebulizer Pressurize liquid though restricted flow.

Salter Labs 8900 Nebulizer Nebulizes at 7 L/min in horizontal or vertical position Large surface area provided by convex cone Designed to maximize output Residual volume 1.7 mL Low cost of $2.99

Pari LC Plus Nebulizer 2 valves to deliver medication Maximizes aerosol delivery, minimizes waste Delivers 20 L/min in 6.5 to 8.5 minutes Residual volume 1.4 mL Cost $

Pressurize liquid through restricted flow. Depends on mechanical force of pressure Depends on size of orifice of spray valve Effective differences require pressure gradients on the scale of several hundred PSI

Malvern Particle Size Detector Used to measure particle sizes of sprays, dry powders suspensions, and liquids Can measure particles from 0.1µm to 1mm Can take a reading once every.4 milliseconds

Design Matrix Salter LabsPari LC Plus Pressurized Flow Simplicity 567 Reliability 565 Ease of Modification 674 Ease of Use 663 Total

Chosen Design: Pari LC Plus Nebulizer Has a more simple design, most easily modified Lower residual volume Higher output

Results Pari LC PlusSalter PSI 9.36µm 8.89µm 15 PSI 8.78µm 7.89µm 20 PSI 8.16µm 7.34µm 25 PSI 7.25µm 6.64µm

Future work- Salter 8900 Nebulizer Baffle shears liquid File down baffle Larger particles are able to pass Baffle structures

Future work- Pari LC Plus Nebulizer Increase clearance Increase size of orifice Results in larger particle size

References Dr. A Rawle, Basic principles of particle size measurement, Malvern Instruments limited Hess D., Nebulizers: Principles and Performance. Respiratory Care. 2 March 2004 Dennis J., Hendrick D. Design of drug nebulizers. J. Aerosol Sci. 2000;Sep:S787- s789. American Academy of Asthma and Allergy Immunity Aerogen, Dolovich M., Labiris N., Pulmonary drug delivery. Br. J. Clin. Pharmacol. 1 March 2004 Prakash Prashanth Ravi Prg. Ast-Grader/Reader, Engineering Experiment Station Malvern Instruments