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

1. Team Members: Joe Bothwell Communicator Kelly Toy Team Leader Jon Cappel BWIG Karim Mahamud BSAC

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

3. ABSTRACT 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.

4. 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.

5. 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.

6. 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.

7. 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

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

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

10. 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

11. 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 $14.95 http://www.allergy4less.com

12. 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

13. 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

16. Design Matrix

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

18. Results

19. Future work- Salter 8900 Nebulizer • Baffle shears liquid • File down baffle • Larger particles are able to pass Baffle structures www.mbsollc.com/inservice5.asp

20. Future work- Pari LC Plus Nebulizer • Increase clearance • Increase size of orifice • Results in larger particle size http://www.allergy4less.com

21. References • Dr. A Rawle, Basic principles of particle size measurement, Malvern Instruments limited • Hess D., Nebulizers: Principles and Performance. Respiratory Care. http://www.rcjournal.com/contents/06.00/06.00.0609.asp. 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 http://www.aaaai.org/patients/allergic_conditions/metered_dose_inhalers.stm 2004 • Aerogen, 2004 http://www.aerogen.com/ • Dolovich M., Labiris N., Pulmonary drug delivery. Br. J. Clin. Pharmacol. www.blackwell-synergy.com/links/doi/10.1046/j.1365-2125.2003.01893.x/full 1 March 2004 • Prakash Prashanth RaviPrg. Ast-Grader/Reader, Engineering Experiment Station • Malvern Instruments www.malvern.co.uk/malvern/ondemand.nsf/frmondemandview