UPTAKE AND EXCRETION OF AEROSOL ANTIPERSPIRANT 647 V=cuum Pump Flowmeter 18" Filter Aerosol Figure I. Exposure chamber and position of monkey head in relation to aerosol 6" In order to reduce the time between exposure and tissue removal, the two animals scheduled for immediate sacrifice were electrocuted. The other two were sacrificed by intravenous administration of pentobarbital. Tissues were removed as quickly as possible, taking care not to contaminate one sample with material from another. For analysis of the radioactivity in the solid tissues, they were finely chopped and then homogenized in a blender. An aliquot of the homogenate was placed on a filter paper disc which was then placed in a Packard©* Sample Oxidizer for combustion and collection of the resulting labeled carbon dioxide. The latter was collected in ethanolamine to which was added meth- anol and a scintillator solution (0.55% Permablend III©* in toluene). This mixture was placed in counting vials and measured in a liquid scintillation counter. t All samples containing more than 200 dpm were counted to a standard error of 1%. Samples containing twice the background count but less than 200 dpm (as determined by a 1-min count) were counted to a 10% standard error. For analysis of liquids, 200/xl. of blood or urine were placed on filter pa- per discs and processed as for solid tissues. *Packard Instrument Co., Downers Grove, Ill. '•Mark I, Nuclear-Chicago, Des Plaines, Ill.

648 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Room air at 6 1./min was drawn through the face mask of the two surviving monkeys and this, plus the exhaled breath, was bubbled through two gas traps containing ethanolamine/methanol (9/4) for collection. A flowmeter at- tached to the inlet of the mask monitored flowrate and respiration. The trap- ping solutions were assayed for •4 CO._, and other non-CO2-radioactivity (pre- sumed to be unmetabolized IPM). PtESULTS The tissue distribution of radioactivity in the two monkeys sacrificed im- mediately after exposure is shown in Table I. For purposes of calculation, these results were averaged. In these animals it may be assumed that metabo- lism was negligible during the 30 breaths taken. Thus, the distribution of label corresponds to the distribution of the total product. Of particular interest was the distribution of activity within the lung. Therefore, we separately measured each lobe. All lobes were very similar, indicating no noticeable variations in the pattern of deposition. Table I Distribution of Radioactivity following Inhalation Exposure (Immediately after Exposure) Monkey A Monkey B (tin x 10 •) (•c x 10 4) Skin or skin substitute (per in. •) 860.00 1360.00 Nasal septum 110.00 324.00 Trachea 9.88 29.70 Bifurcation 6.92 5.95 Lung (total) 109.41 67.13 Stomach 1.28 108.48 Esophagus 3.19 16.66 Bile 0 0 The tissue distribution 24 hours after exposure is given in Table II. It will be noted that the total exhaled radioactivity is comparatively high. No radioactivity was found in the blood and urine samples in monkeys A and B. In animals C and D, urine samples were collected periodically and blood was taken after 5 rain and again after 24 hours. The levels here were very low. This is shown in Tables III and IV. The airborne concentration of radioactivity in the exposure chamber dur- ing the exposure was obtained by assay of the exit port filter. These results are shown in Table V, along with the concentration of spray formulation to which they correspond. These values were very reproducible.