781 



CIGARETTE YIELDS AND SMOICE BIOAVAILABILITY 317 



and 255." ng,'mi for ihe original and dupiicatc samples, respectively. The mean dif- 

 ference of 9.0 ng/ml had a SEM of 3.2 nj/ml. There was no statistically signilxant 

 pair^ise difference between the original and dupiicatc values for cither nicotine or 

 cotinine, at the 5% kve! of significance. 



In a previous study (19), utilizing the same methods of analysis for cotinine and 

 :oiine. inienerenoes from other compounds were excluded after measuring a random 

 jup of samples by high-resolution gas chromatography and mass speciromctiy. 



Expired Carbon Monoxide Determinations 



Expired air samples were obtained at the time of blood withdrawal by having the 

 respondent loosen aB tight fitting clothes, assume a standing position, take a full deep 

 breath, hold it for 5 sec, and exhale all but the end tidal air, which was then coUcaed 

 in a 1-liter polyethylene sample bag. The CO concentration was measured iramcdiatdy 

 using a carbon monoxide analyzer (Ecolyzcr, Energetics Sciences, Inc., Elmstead, 

 N. Y.), with a sensitivity of ±1 ppm, on the fuD scale from to 100 ppm. 



RESULTS 



A very close similarity of data allowed a combined analysis for both sexes. Brand 

 yields are those reported by the Federal Trade Commission (14). Because of »«U- 

 known production variations and seasonal drifts, the actual yields of the cigarettes 

 smoked by the subjects might have been somewhat different from FTC figures. Data 

 arc presented graphically as a sequence of interval means. It is emphasized that this 

 representation shows only the overall trend in the data; each mean, by itself, is com- 

 prised of several dau points. Ninety-fivt percent confidence bounds (broken hncs) 

 indicate the extent of scanering. A scatter plot of the original plasma nicotine mea- 

 juremenis is given to illustrate the extent of variance, which is similar for plasma 

 cotinine and expired CO data sets. Linear regression equations are given where desir- 

 able. However, it a clear that true functions involving nicotine or CO intake are 

 nonlinear and must intersect (0,0) cotDrdinatcs: 



Plasma Sicotine and Cotinine as a Funaion of Cigarette Yield 



Individual levels of plasma nicotine are presented as measured to emphasize their 

 pharmacodynamic significance, and are gjvcn in Fig. 2 as a function of FTC nicotine 

 yields. The figure shows a close correspondence in slope and intercept with the mean 

 sample trends of Fig. 3. Plasma cotinine values correlated with FTC nicotine yields 

 in a pattern similar to that of plasma nicotine ()'= 225.3 -i- 74.4^ r = 0.23, /*< 0.001) 

 and their mean sample trends are also reported in Fig. 3. 



Nicotine Intake 



The transformation of plasma nicotine data according to cigarette consumpdon, 

 body weight, volume of distribution, and clearance give an estimate of mean nicotine 



