785 



CIOAKCIIC. TICLU;) A>U iMi-'KX. OIVJA » AnvSOiLJ « I 



CLgarctItt 

 p«r Day 



RC Nlcotlna (mg/dtf 



Fw. 5. Mean values of cigarettes smoked per day as a function of FTC oicoiine yield (95% cotiJence 

 intervals). 



MNIC varies only between 0.75 and 1 .25 mg/cigarette (Fig. 4), corresponding to mean 

 steady-state nicotine plasma levels between 25 and 45 og/ml (Fig. 3), despite a much 

 greater variation of FTC cigarette yields from approximately 0. 1 to 1 .6 mg per cigarette. 

 The limiting factor is probably nicotine intake itself, since plasma nicotine and codnine 

 values display similar ceilings, while the nicotine to cotinine conversion rate remains 



PUsma NIcotina 

 (no/mO 



I ' I ' I ' I ' I ' 



J I 



Ogaranaa par Day 

 Fig. 6. Mean piasnu nicotine values as a function of cigarettes smoked daily (95% confidence ioierrals). 



