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. 13 - exist beWeen the smoking conditions which we chose, and the natural "intermittent" smoking: 1. As a consequence of the lack of smoking pauses, in the continuous puff there can be practically no loss of nicotine into the side stream smoke. 2. The rate of flow is constant in the case of the continuous puff, and corresponds to a flow rate of 1 1/3 ml/soc. In intermittent smoking, normally a volume of 35-40 ml is sucked in within 2 seconds, in the case of 1 or 2 puffs per minute. The x'loar rate is therefore 15 times higirer during a puff than in the case of the continuous puff; this has as a consequence the fact that the gloi•ring zone temperature is subject to greater variations, and higher ma.yimvm temperatures are obtained. Therefore, higher losses are to he expected from hoati.ng. NrnaovAr: A rrFatPr flow rate must also decrease the absorption in the tobacco butt. Actually i••e detPrminedd that in the case of intermittent smoking a con- sidcrably higher portion of the nicotine contained in the burned tobacco is lost, and that the aricunt absorbed. in the tobacco butt is significantly r smaller. The totp•1 nicotine leaving the cigarette in the main stream of smoke is like*•-rise somei•rhat smaller. On the other hand, we could also deter- mine differences in physical-cheTdcal behavior of the nicotine in the smoke which werc characteristic of the types of tobacco investigated, in the case of int,)r.m.lttent smoking. To be sure, Lreater difficulties are involved in the quantitative determination of these differences in the casa of inter- mittent smoking. . It is known to be difficult to determine the nicotine alon~•, in rni; - turos with pyridine and its derivatives. ~lhilc in tobacco and in the total

S carbon, which proves to bo present in the rogion where the oxygen is sucked in,'and combines completely with the oxygen, bringing about further dis- tillation and pyrolysis because of the heat oS combustion set•iree. It is rEn•rardins to emiu'asize this method of origin of the smoke, in order in this way to dispel the widespread error, according to which smoke should be made physiologically harmless by a "complete combustion." Structur.e of the cicarette smoke. In an invisible medium (the so-called gas phase) there are suspended as r. so-called particle phase about 3 billion droplets per cubic centimeter of space; these droplets have diameters of 0.1 to 1 11 (Keith and Derrick5). In the physical sense, these two portions are differentiated above all by their readiness for contact. Since free diffusion prevails in the gas phase, components in their forward motion in the smoke come quantitatively into direct contact with the bodies in their surroundings (pieces of tobacco, paper, filter fibers, saliva in the mouth, etc.) in a~.ztter of seconds. The droplets in the particle phase, on the other hand, behave very slug- gishly, and come into actual contact with the surroiindin~s only when these offer especial.ly large surfaces and a very fine subdivision of the smoke in the smallest space elemonts, such as is the case in an effective s.nol:c fil- ter or even in the lungs. In a chemical sense it has been shown'that by far the grAa.test nuaiber off smoke constituents are distributed in some ratio in both phases. Only a few substances with extremely low or extremely high boiling points are practically limited to one of the two phases. In Ennor- al, nore than °9p1' of the nicotine is in the particle phase6 , so thst for determination of the nicotine in smoke only the condensed particle phase is custorarily nmlyzr:d. f;owevcr, until recently, the .^.en:,itivity of the dis- tributien aquilibri>>m had been cons3.derably urn-lorestim~.ted: whon nicotino

3 took up an intermediate position. The behavior of the nicotine upon smoking proved to be quito dependent upon the pH value of the smoke. Most striking are the differences in the "oral cavity." There, the "saliva" took about four times as much nicotine from the basic smoke as from the acid smoke! T~bacco ype M Ilico- .tinR per.~ tobac-i co ( a e o, •a cot ,:e u:'i.,lt; srae ng ' ~ of nicotin ~onta ned in smoked ~, ,r,no .,`'r„e~, I le.rin stream t Vola- ~ rc-d r+ p?i of liz~ sorh~d e: - the ' r F}yro- ~. ine-~ . Tow ' n the by~ thn 1~'' Qd ~ -- butt, ivall~pA,,.ed s:no`ce • Virgin Rhod. 14,4 30 70 42 2,6 2s 5,0 Virgin USA 13,3 29 71 45 3.1 23 6.2 Maryland USA . 10.2 30 70 30 6,0 26 6,1 Psrsgusy 11.6 .6 94 34 13,2 .47 7,7' Burley Japsn . 27,4 '10 28 . 11,2 46 6.0 , . , . . . ~ ~.; ` ~. .~:....a...,~.: Fig. 1. Percenta6e distribution of tobacco nicotine among its ~... _ t _t .. T, . . ! ! 1 .' _ , 9 • YQl1~l4J ~lr,r1C:~lvil,r,.V PiNVt V:IC vu,vA.J.Ai6• •L1G 1,YSli1 111bV16dN 11GJ in the relationship between the pH value of the smoke and the nicotine absorption in the saliva of the mouth. The nicotine v:hich had passed the oral cavity, in the case of !'_cPr inhalation, was taken up to the extent of over 90o in the lung (Borbely 4 ). In this case, practically thc entire nicotine from the smoke Goes over into the body of the smoker, so that the smoke nicotine content is of a very certain and direct value as evidcnce. However, inhalation is a relatively young custom, and hazardous to health; here we are proceeding from the assumption that tt:e smoke is not inhaled.. In the caso of the two basic tobaccos this is also scarcely possible, since the basic smoke produces a painful irritating effect in the larynx. . For the understanding of the measured values, some information concern- ing the origin and r.tructure of the smoko is necessary.

- 12 - influence the vapor pressure and thus the "absorbability" of the nicotine in a buffered medium, we have, on the other hand, found the pronounced dependence upon the pFI of the smoke to be confirmed in the case of all of the investigations carried out thus far. Table 5. Amounts of nicotine ("total alkaloids") per cicarette. Average values from 3 determinations, in each case on one ciga- rette. In the last two columns, the three individuEl, measure- monts are also given. (P'cr percentage distribution, see Fig. l.) i I Years Types of t smo}:ec ,os -. zn ,o-tin^ soroc in the so,• e In :e . in t.~:e I sma!ce, tobacco tob~.cco nd siae tobacco saava conden- St:ri bU Bt . S t 3 ~g m m g mg ~ Virgin 0,32 3,48 Rhodesien 0,33 ' - 3.66 0,40 ' 3,23' 13,8 4,2 6,8 ' 0,35 3,45 Virgin USA 0,33 2,61 0.28 2,16 ' 0,38 2,60 10,6 3,1 4,8 0,33 2,42 Maryland USA " n.n ~ a! 0,42 1,91 0,38 1,40 6,7 2,0 2,8 0,l0 1,68 Paraguay ' 1,21 4.64 1,08 ; 3,98 1,32. 4,17 9,1 0,65 ' 3,1 1,20 .. 4,23 Burley Japan 2,6G ' 11,03 2,12 10,24 3,34 11,20 23,8 3,7 8,8 2,87 10,82 eC~o, '.-1Prnischh had esti:-r~).ted the fraction of the tobacco nicotine taken up from the smoke in the case of mouth smoking as 2-5~ from "acid" ci~arottes on the basis of an entirely different type of inea5urement. The values for Virgin found in our model experiments (Figure 1) agree amizinZly With this. In the interpretation of the exporimenta.l results, obviously the fact must be taken into consideration thot above a11 the followint- difforences

7 via the previously mentioned disturbance and reestablishment of the dis- tribution equilibrium, without actually coming into direct contact with it. I'7aturally this effect durin7 the short time oS residonce of two seconds assumes agroater importance, the more volatile the nicotine in the smoke particles is, i.e., the higher the pH value of the smoke ist .Absorntion in the ci;arettc butt: here the butt is understood to be the unburned tobacco residue, with no filter. A considorable portion of the smoke particles are held back on this tobacco, on account of its great sur- face. In add.ition to this, the tobacco fibers also influence thc smoke via its ~a.s rha.se. From this, we i-rould have to conclude that basic smoke also leaves behind more nicotine in the butt than does acid smoke. However, tho contrary is the case, on grounds which will be discussed later. ExnPri.^,~nt_1 ~c`hn~3s • fn,• niir i mrACt.i na t.i nrG wrrA n7•Eh11'ed on an auto- no tic lUac'1L''1~ ('•~olins '::~rk VIII). Len~th: 70 mm; dianeter: 8.3 m;7. I'orr each type of tobacco, the average cigarette weir,,,ht was determined after prior conditionin- at 60;' relative humidity and 20°C. 1'ie used. exclusively cigarcttcs i*nic'a varicd by less than 20 n- from the average weig-tit (techni- cal d.at.1, TKble 2). Ta.b7e..'.. Tec%nical data on the ciCarett.es investiCated. The duration of bun:,in•, is b•+sed on thF srro;ces' len,-th of 47 mnl at a flou of 80 m1 por rlinutc. TJlls iJ~ , w.~urat~-r;j watn° cc:n. !1vv tr- :0tt af Y,r,. nir. • t0'rt of ~ °l,r/ci.~^.rct Virgin Rhodoeian 1428 10,0 13,0 Virgin USA ` 1189 9,4 12.2 Tlaryland USA 948 6,4 ~ 11,2 P6raSuay 1173 8,9 11,3 13urloy Japan 1281 9,0 11,6 i

8 The Rr.porimental arranCemnnt for the sr,okfno m1y be tseen from Figures 3 and 4. Tho mouth piece of the ciCarctte is fastened to the ci.&,arette holder by an airtight connection 1•rith thin latex mambrane ("dontal dar,;" ). An a.ntor~^tic smol:in- ihachine of the "cigarette components CSM 10" type guarantees reproducible suction conditions. Ths fresh s:noke passes first thNough a Elass tube held at 37°C in airr.~ter bath, in which there is 0.6 nil of an absorption liquid whi.ch i:nitates the ::aliva of the mouth. This arti- ficial "saliva" conaists of 0.25 ?t phosphate buffer 4rith the addition 'af 100 p;+n of sa,wni n. The p•FI valu° was adjustod to 6.5, which corrosponds to the zvPra;;e va'!vc of ?^.uian saliva. ."\f.t-;r the c,at from the g11^s tube, the SmO~\E' ~nJi ^s through fi.nc filter ("CaTb:•id~e Filter"), An whi.c hch over 90.;,1f? of the particlcs cf (`.3 '1 c?i cr.;cter cont1ined in t'ie smol:e are held baclc6. This "smoke ~condea- sato" ("totn.) rsrticulat~ natter") which is precipitated on the fibcrgla•s : filtcr contains aa:on;; ether thin;;s practically all of the nicol,inE3 from t}:o s^ro:'c nz:sin,- throu3h it. In thc case of mouth smol:i.n~ (without inhalation) the sn:ol~e is : ucked into the nouth, t•here for one to t~-o seconds ;.n contact with the rr.oist mouth surface, and is then F:::pelled again. BetrTa.^,n successive smok: puffs there irs a rinsin~ of the r~outh sv.rfaces by r!;nct•ral of the saliva. Thc total 1^:cur.t of SUrf1co in t.ho oral cavity, as i•rell as its rinsin~ bet!rren sieccrssi.ve s•noke puffs, is probably susceptible to stron~;1•y indi- vidna1 vr.riltior.:>, •^•nd is di.ffi.cult to ricasure. In order to takc into r.ccowit those t-ro rlctor: in our c;;perimo:.t, in spi.t.c ot tizis, vc have ur.cc' a viL-ratur (50 vibrat,ion: p~,r second) to move the tLbe with the buffer solution. In this vrav the surface of thc artificial saliva i.s Lrer>tly in- (ir.-ivc forPl3tion) an,-' Zn addition :.s contin»zll;,~ rcnc~•rert.