Tobacco Documents Online

ULTRASONIC GENE ZATION OF AN AQUEOUS NICOTINE AEROSOL FOR SUBJECTIVE TESTING Peter J. Lipowicz 2 April 1991

HYPOTHESIS: SUBJECTIVE RESPONSE TO NICOTINE AEROSOL CAN BE ALTERED BY CHANGING AEROSOL PH • Impact • Physiological response • Protonated nicotine vs. basic nicotine

RESEARCH PLAN • Generate nicotine aerosol at controlled~ pH • Measure subjective response with panelists • Determine validity of hypothesis • Determine applicability of hypothesis

CHARACTERISTICS OF THE IDEAL AEROSOL GENERATOR • Subjectively neutral matrix • Controllable and sufficient nicotine concentration • Controllable aerosol pH • Steady and reproducible output • Amenable to panelist testing

THE ULTRASONIC AEROSOL GENERATOR • Generates aqueous solution • Aerosol composition is same as solution composition • Nicotine concentration of solution can be varied • pH of solution can be adjusted with addition of acid • Can generate high concentrations, • Compact commercial units available

G.n4rator R.stfrotr (E): G.ys.r(0)

2020j26841

ISSUES IN THE DEVELOPMENT OF THE TEST PROTOCOL • Nicotine level -- 20'to 30 ug per puff • Acid to adjust pH -- phosphoric acid • Measurement of aerosol pH -- pH paper • Isotonicity of solution -- not controlled • Sterility of solution -- filter sterilized • Sterility of generator -- autoclaved'~ • Nicotine concentration in aerosol -- spectrophotometry • Venting excess aerosol -- installed hood in Frank Gullotta's laboratory • Sampling prodecure • Reproducibility of aerosol production • Physical nature of aerosol

REQUIREMENTS OF SAMPLING PROCEDURE • Simplicity • Delivers controlled volume of aerosol • Similarity to cigarette -- inhalation by puffs -- puff volume -- pressure drop -- size of mouth end

STABILITY AND REPRODUCIBILITY OF AEROSOL OUTPUT • Required so that nicotine level can be controlled • Medium rate ( 1 g/min ) is not reproducible -- varies for different aqueous solutions • High rate(4.5 g/min ) isbetter-- less affected by solution composition

COlVIP ' !SON OF PHYSICAL CHARACTERISTICS OF ULTRASONIC AEROSOL AND CIGARETTE SMOKE • Particle size • Deposition in the respiratory tract • Stability

SIZE D~ISTRIBUTION OF UL'I'RAS'ONIC AEROSOL FROM DEVILBISS ULTRA-NEB 99

lob

2020126848 Figure 13.12 Water droplet lifetimes as function of droplet size for 0, 50, and 100% relative humidity at 20° C.

GOALS OF PRELIMINARY TFSTING' • Adjust nicotine solution concentration • Specify certain pH levels • Adjust pressure drop in sampling tube

CURRENT PROCEDURE • Make 200 ml of 0.01 M nicotine(0.17%)! in~ water • Adjust pH of solution to range of 6 to 9' with phosphoric acid • Filter sterilize solution • Sterilize ultrasonic nebulizer in autoclave • Generate aerosol at highest power setting ( 4.5 g/min ) • Confirm nicotine level in aerosol ( 30 ug per puff }. • Subject samples every 30 sec for next 4 - 6 min

CITRRENT STATUS • Aerosol generator is set up~ in Frank Gullotta'slaboratory (T426) • We are testing different procedures for measuring nicotine concentration in the aerosol • Preliminary subjective testing has not begun

CONCLUSIONS • We have developed an aerosol generation system for subjective testing of an aqueous nicotine aerosol • We have resolved the major issues concerning, the test protocol • Once in place, this protocol can serve as the basis for protocols to test other substances