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United States Patent: 4,055,191 Page 14 of 23 *As palladium **As nitrate nitrogen - ***From infrared spectral absorption in the region of aromatic C vibrations. (11.9-14.0.mu.) Once again, the cigarette containing both palladium and magnesium nitrate afforded materially lower PCAH concentrations than those treated with either palladium or magnesium nitrate alone. By comparing the data for Samples 1 and 4, it can be seen that ammonium hexachloropalladate gave lower PCAH levels than the corresponding tetrachloropalladate. EXAMPLE III A 1.0-gram portion of ammonium hexachloropalladate was dissolved in 100 cc of water and added to 56.6-grams of sugarglycerine-propylene glycol casing solution. A 27.84-gram portion of hydrated aluminum nitrate, Al(NO.sub.3).sub.3.9H.sub.2 0, was dissolved in the casing solution and the mixture sprayed onto 400 grams of a cut tobacco strip blend (32 cuts per inch), (Sample 6). The final tobacco blend contained 0.06 percent by weight palladium and 0.65 percent by weight added nitrate nitrogen and 0.75 percent by weight total nitrate nitrogen. A blend containing only the Al (NO.sub.3).sub.3.9H.sub.2 0 was prepared in a similar manner, (Sample 7). These samples were tested as described in Example I, and the data obtained are tabulated with Example IV for a typical run. Data for Sample 2 and the Control of Example I are included for purposes of comparison. EXAMPLE IV The same equipment, procedure and materials used in Example III were used in Example IV, except a 22.56-gram portion of potassium nitrage was used in place of the Al(NO.sub.3).sub.3.9N.sub.2 O. The final tobacco blend (Sample 8) contained 0.06 percent by weight palladium, 0.65 percent by weight added nitrate nitrogen and 0.75 percent by weight total nitrate nitrogen. A blend containing only the potassium nitrate was prepared in a similar manner, (Sample 9). These samples were tested as described in Example I, and the data obtained are tabulated with Example III for a typical run. Data for Sample 2 and the Control of Example I are included for purposes of comparison. CONCENTRTION OF PCAH http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HIT.../405519 2/13/01

United States Patent: 4,055,191 - Page 12 of 23 Tobacco balance to 100% The smoking composition may be further processed and formed into any desired shape or used loosely e.g., cigars, cigarettes, and pipe tobacco in a manner well- known to those skilled in the tobacco art. Alternatively, solutions of soluble palladium compounds, suspensions of palladium black in casing or water or powder mixtures can be dispersed by atomization or other convenient means on reconstituted tobaccos manufactured by methods other than the one described above or on synthetic tobacco substitute materials. A further understanding of the invention will be had from a consideration of the following examples that amy be used in actual commercial practice and are set forth to illustrate certain preferred embodiments. EXAMPLE I A 0.77-pound portion of ammonium hexachloropalladate was dissolved in the minimum amount of water necessary and the solution was added to a mixture of sugar-glycerin-propylene glycol-water casing solution. A 18.94-pound portion of magnesium nitrate hexahydrate was dissolved in this mixture and sprayed in a conventional casing applicator onto 222 pounds of uncut strip tobacco blend. The treated tobacco was blended with 63.0 pounds of reconstituted tobacco sheet and 15.0 pounds of stems. The resulting blend was cut at 32 cuts per inch (Sample 1). Blends containing only the palladium (Sample 2) and only the magnesium nitrate (Sample 3) as well as a control blend containing neither additive were prepared in a similar manner. Each of the three samples and the control blend were pyrolyzed in a special pyrolysis reactor consisting of a steel cylinder about 4 inches in diameter and 5 inches along with an annular space at the central perimeter covered with a stainless steel screen. Cut tobacco was packed into this reactor at densities similar to cigarette densities and the tobacco was lit at the exposed perimeter. The burning tobacco itself thus produced the necessary heat for pyrolysis and the reactor closely approximated on a large scale the conditions extant in a burning cigarette cone. The combustion and pyrolysis products were pumped out through a small tube positioned concentrically with the cylinder and the dry solids in the smoke were analyzed for PCAH content. The concentrations of PCAH from the test tobaccos, as a percent of the concentration of PCAH from the control tobacco are tabulated as follows for a typical run: http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1 &Sect2=HIT.../405519 2/13/01

United States Patent: 4,055,191 _ Page 7 of 23 not necessarily a reliable indicator of the additives' effect on the bulk of the PCAH. It has been postulated that the effect of nitrates on the composition of cigarette smoke stems from two properties of nitrates: (a) their capacity to function as oxidants, and (b) their capacity to form the unpaired electron species, nitric oxide, in the pyrolysis zone of the cigarette that acts as a free radical scavenger. Provided a sufficiently high level is added, all nitrates tend to lower the PCAH yield of cigarettes to some degree, but depending on the particular cation, not necessarily the concentration of PCAH in the smoke condensate, as indicated in the Pyriki et al. article discussed above. DESCRIPTION OF THE INVENTION It has now been found that the concentration of the PCAH fraction normally found in the smoke of a natural leaf smoking tobacco can be substantially reduced without adverse organoleptic effect on tobacco smoke by incorporating both palladium, in metallic or salt form, and an inorganic salt of nitric acid. It has been further discovered that the tobacco compositions of the present invention are unique in their ability to significantly reduce the biological activity of tobacco smoke normally produced from tobacco upon pyrolysis. The present invention involves the application of these surprising discoveries to cigarettes, cigars, pipe tobacco and other smoking tobacco compositions. Accordingly, it is an object of this invention to provide smoking tobacco compositions which on burning substantially reduce the concentration of PCAH in the tobacco smoke. Another object of this invention is to disclose a combination of chemical materials which when present in a smoking tobacco preparation substantially reduce the biological activity of the tobacco smoke. Still another object of the present invention is to provide smoking tobacco compositions which substantially reduce the biological activity of the smoke and are acceptable to the smoker from a standpoint of palatability. A further object of the present invention is to disclose a cigarette which produces less PCAH and a lowered biological activity on smoking. These and other objects of this invention will be apparent from the accompanying disclosure and appended claims. DETAILED DESCRIPTION OF THE INVENTION In accordance with the present invention, the biological activity and the concentration http://164.195.100.11/netacg'i/nph-Parser?Sectl=PTO1&Sect2=HIT.../405519 2/13/01

United States Patent: 4,055,191 Page 9 of 23 grade Mg(NO.sub.3).sub.2.6H.sub.2 0 which contains (on a weight basis) less than about 0.0005% chloride ion, 0.005% sulfate ion and 0.0004% heavy metals (calculated as lead). In addition to the nitrate salt other metal salts capable of releasing nitric oxide are useful in the practice of the present invention added to the tobacco in amounts of from about 0.25 to about 0.75 weight percent, calculated as nitrate nitrogen, based on the weight of the tobacco. Illustrative of these are the various inorganic nitrite salts such as lithium nitrite, sodium nitrite, potassium nitrite, magnesium nitrite, calcium nitrite, hydrated salts thereof and mixtures thereof. Using the generally accepted standard toxicological procedures described in the disclosures of Industrial Toxicology, 3rd Edition, Hardy, et al., Acton Mass., Publishing Sciences Group Inc., 1974; Merck Index, 8th Edition, Rahway, N.J., Merck & Co., Inc., 1968; Sax Dangerous Properties of Industrial Materials, 4th Edition, New York, Van Nostrand Reinhold Co., 1975; and Toxic Substances List, 1974 Edition, Rockville, Md., NIOSH, 1974, as the basis for forming guidelines as to the potential toxicity of metals and their salts, the following is a list of those metals whose nitrate salts would be less suitable, from a toxicity standpoint, in the practice of the present invention: antimony, beryllium, barium, cadmium, chromium, cobalt, indium, lead, mercury, nickel, osmium, polonium, ruthenium, selenium, silver, thalium, vanadium and zirconium. If any of the nitrate salts of these metals are used in the practice of the present invention, means must be provided to remove the metals from or to lower the concentration of the metal to a non-toxic level in the smoke stream. Inasmuch as the role of the nitrate salt in the present invention is believed to be due to the ability of the salt to form nitric oxide in the appropriate temperature region of the combustion zone the choice and concentration of the nitrate may vary accordingly. Prior to the present invention, many of the nitrates and, in particular, nitrates of Group Ia metals were known to be good combustion promoters. When they are added to tobacco, the burn rate of the cigarettes is accelerated and the total smoke yield is decreased. The concentration of PCAH within the smoke condensate is, however, not necessarily decreased and is at times increased (Pyriki et al., above). The nitric oxide yield of such nitrates is relatively low. Hence, nitrates of Group Ia metals have to be added at relatively higher levels to achieve an equivalent reduction in the concentration of the PCAH in tobacco smoke. In addition, the added nitrates, and in particular those that accelerate burn rate when used in amounts taught by the prior art (5-10%), impart a disagreeable taste to the main stream of smoke and an obnoxious odor to the side stream aroma, thereby making the cigarette unacceptable from the point of view of a palatable cigarette. Thus, nitrate salts, when used alone in tobacco, have not proven to be universal http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HIT.../405519 2/13/01

United States Patent: 4,055,191 Page 8 of 23 of PCAH is substantially reduced without adverse organoleptic effect on tobacco smoke by incorporating in tobacco a catalytic mixture of palladium, in metallic or salt form, and a nitrate or nitrite salt of a metal selected from Groups Ia, Ib, IIa, IIb, IIIa, IIIb, IVa, IVb, Va, Vb, and the transition metals of the Periodic Table of Elements. Palladium may be incorporated into the tobacco composition in finely divided metallic form, for example palladium black, and/or in the form of a salt which is decomposable in situ, preferably by heat, into metallic palladium. Water-soluble palladium salts are preferred because they are readily incorporated into and distributed throughout the tobacco composition. Illustrative examples of suitable palladium salts include simple salts such as palladium nitrate, palladium halides such as palladium chloride, diammine complexes such as palladous dichlorodiammine (Pd(NH.sub.3).sub.2 Cl.sub.2), and palladate salts, especially ammonium salts such as ammonium tetrachloro-palladate and ammonium hexachloropalladate. One form of palladium which has been found to be particularly effective in combination with tobacco to provide the smoking composition of this invention is ammonium hexachloropalladate, (NH.sub.4).sub.2 PdCl.sub.6, (Research Organic-Inorganic Chemicals Corp.), 99.5% pure. The catalytic amount of palladium associated with the tobacco in the smoking composition is in the range of between and 0.OOlto about 1% by weight of the tobacco used to prepare the smoking composition. Although the reduced yield of polycyclic compounds arising from pyrolytic reactions of the composition have been achieved at these levels, it has been found that the best results are obtained when the palladium is in the preferred range of from about 0.01to about 0.1% based upon the weight of the tobacco. - The nitrates which are employed in accordance with the present invention are the nitrate salts of metals of Groups Ia, lb, IIa, IIb, IIIa, IIIb, IVa, IVb, Va, Vb, and the transition metals of the Periodic Table. The particular nitrate salt chosen for use in the practice of the present invention is one which is deemed to be non-toxic when present in the smoking compositions of the present invention. Illustrative of the various nitrate salts which are suitable for use, from a toxicity standpoint, in the practice of the present invention are the nitrates of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, yttrium, lanthanum, cerium, neodymium, samarium, europium, gadolinium, turbium, dysprosium, erbium, scandium, manganese, iron, rhodium, palladium, copper, zinc, aluminum, gallium, tin, bismuth, hydrates thereof and mixtures thereof. Preferably, the nitrate salt is an alkali or alkaline earth metal nitrate. More preferably, the nitrate is selected from the group of calcium, magnesium and zinc with magnesium nitrate being the most preferred salt. A magnesium nitrate which has been particularly effective in combination with palladium and tobacco to provide the smoking composition of this invention in A.C.S. http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1 &Sect2=HIT.../405519 2/13/01

United States Patent: 4,055,191 Page 18 of 23 Observation of tumor and outgrowth development was made each day during condensate application. Formal checking was performed monthly after the first observation of a tumor or outgrowth and as the incidence of tumor development increased the formal checking was made biweekly. Gross visual observations include diagnosis of several kinds of non-tumorous outgrowths (warts, spicules, etc.), positive papillomas, and possible or probable carcinomas. At death or sacrifice, all outgrowths were examined histopathologically to confirm or extend the visual observations. The data in Table I summarizes the condensate yields and the mean amounts applied per animal for each of the cigarette groups. Each mouse which survived to termination received 375 applications of condensate. TABLE I Smoke Condensate Yield and Application Smoking Data Application No. of Total Total Yield (gm)* Average** Cig. per Sample Smokings Cartons Condensate per 100 (mg Control of 50%) Application A B 36 36 36 90 94.5 93 839.2 872.8 826.4 46.6 56.2 44.4 101 99 96 1.1 1.1 1.1 Acetone Control 100 -- *Grams of condensate yield pr 1000 cigarettes. **Mean average amount of application in milligrams of solution ( weight condensate in acetone). The tumor incidence data, as observed grossly during the experiment, are presented in detail in Table II. The one papilloma grossly observed with the condensate from cigarette Group B, tobacco treated with palladium and magnesium nitrate hexahydrate, occurred very late in the experiment while the Control cigarette, untreated tobacco, produced the earliest and highest incidence of tumors. http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HIT.../405519 2/13/01

United States Patent: 4,055,191 CONCENTRATION OF PCAH ADDITIVE WEIGHT ~ RELATIVE TO CONTROL SAMPLE (NH.sub.4).sub.2 PdCl.sub.6 * Mg(NO.sub.3).sub.2 ** WEIGHT BASIS IR ANALYSIS*** Control 100 100 1 0.06 0.55 50 50 2 0.06 60 59 3 -- 0.55 78 78 Page 13 of 23 *As palladium **As nitrate nitrogen ***From infrared spectral absorption in the region of aromatic C bonding vibrations. (11.9-14.0.mu.) EXAMPLE II A 0.64-gram portion of ammonium tetrachloropalladate was dissolved in 100 cc of water and added to 56.6g of glycerine-sugar-propylene glycol casing solution. A 27.5- gram portion of magnesium nitrate hexahydrate was dissolved in the casing solution and the mixture was sprayed onto 400g of cut strip blend (32 cuts per inch) (Sample 4). A blend containing only the (NH.sub.4).sub.2 PdCl.sub.4 was prepared in a similar manner (Sample 5). These samples were tested as described in Example I, and the data obtained are tabulated for a typical run. Data for Sample 3 and the Control of Example I are included for purposes of comparison. CONCENTRATION OF PCAH ADDITIVE, WEIGHT % RELATIVE TO CONTROL SAMPLE (NH.sub.4)PdCl.sub.4 * Mg(NO.sub.3).sub.2 ** WEIGHT BASIS IR ANALYSIS*** Control 100 100 3 -- 0.55 78 78 4 0.06 0.55 57 59 5 0.06 -- 80 78 tC http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1 &Sect2=HIT.../405519 2/13/01

United States Patent: 4,055,191 TABLE II Gross Tumor Incidence During Experiment Control A B Weeks A P A P A P 23 1 1 27 1 1 31 2 2 36 3 4 1 1 40 3 4 2 2 44 4 5 3 3 48 8 10 3 3 53 8 10 5 58 12 15 7 8 62 13 20 7 8 1 1 66 14 24 9 12 1 1* 71 16 27 14 21 1 1 73 18 33 16 24 1 1 75 18 35 16 29 1 1 77 19 37 17 32 1 1 79 20 38 18 34 1 1 Page 19 of 23 A = Number of papilloma-bearing mice. P= Cumulative total of papillomas observed. *At 66th week observation, the observed papilloma of the mouse i Group B regressed, i.e. disappeared. The final tumor data for a experiments is presented in Table III. The data includes the fin observations at the end of the 80-week test period, number of ad new tumors and tumor-bearing animals added at necropsy, tumor an tumor-bearing animal totals, the effective number of animals and incidence. The effective number of animals is the number survivi time of appearance of the first tumor in each group. The tumor i is the tumor-bearing animals as a percentage of the effective to The differences in the data collected during gross external observation and at final diagnosis at necropsy can be attributed to the following factors: (1) the regression of papillomas which are still counted as part of the total incidence, (2) histological confirmation of an outgrowth or papillomas as either papillomas or carcinomas, and (3) new papillomas or carcinomas which were detected only after necropsy. m ~ ._- The grossly observed papilloma in the condensate from the cigarettes of Sample B m ~ regressed within a 4-week period, and the newly observed papilloma noted at 4h- , necropsy, was noted as positive but at a very early development stage. _. cn_ 0 The greatly reduced activity of the cigarettes of the present invention, cigarette http://164.195.100.11/netacg•i/nph-Parser?Sect1=PTOl&Sect2=HIT...l405519 2/13/01

United States Patent: 4,055,191 Page 21 of 23 The survival of the experimental animals, showing the respective death dates for each animal, divided in tumor-free and tumor-bearing groups, is presented in Table IV. The data confirms the conclusions of the tumor-incidence data presented in Tables II and III, that is, the experimental animals which were painted with smoke condensate from tobacco treated with both palladium and magnesium nitrate hexahydrate showed a significant reduction in biological activity. The PCAH concentration data for the cigarettes of the 3 biological test groups is presented in Table V. The same equipment and procedure used in Example I were used to collect and measure the PCAH of the smoke condensates of the biological test groups of cigarettes. The PCAH concentration of the smoke condensate from the cigarettes of Sample B (tobacco treated with palladium and magnesium nitrate hexahydrate) was only slightly lower than that of Sample A (tobacco treated with palladium alone); however, the biological activity of the smoke condensate of Sample B was significantly lower than that of Sample A. While the PCAH concentration of the smoke from the additive cigarettes was decreased, the observed reduction in the biological activity may have been the combined result of reduced PCAH concentration and a reduction in the concentration of other select biological active species in the cigarette smoke. The calculations used in Table V for deterniining the PCAH concentration values relative to the controls were used to arrive at the relative PCAH concentrations reported throughout this specification. Other conventional tobacco additive materials, such as flavorants and humectants, in addition to those described above may be used in the practice of the present invention without deviating from the scope thereof. However, certain experimental results have indicated that the addition of long chain fatty acids in relatively large amount (about 4% by weight) to the tobacco is not as effective in the practice of the present invention. References herein to biological activity of tobacco smoke are based solely on the results obtained from experimental animal testing procedures following conventional protocol, such as set forth hereinabove. While the invention has been described in detail with particular reference to preferred embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims. TABLE IV http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HIT.../405519 2/13/01

United States Patent: 4,055,191 Page 15 of 23 ADDITIVE, WEIGHT % RELATIVE TO CONTROL OF TOTAL BLEND WEIGHT IR SAMPLE KNO.sub.3 ** (NH.sub.4).sub.2 PdCl.sub.6 * A1(NO.sub.3).sub.3 . 8H.sub.2 O** V-VX43 BASIS ANALYSIS*** d. Control -- -- 100 100 2 -- 0.06 -- 60 59 6 -- 0.06 0.65 64 58 7 -- -- 0.65 77 62 8 0.65 0.06 -- 63 52 9 65 0 -- 70 68 . \~-y a_dVI-003 *As palladium **As nitrate nitrogen ***From infrared spectral absorption in the region of aromatic C bonding vibrations. (11.9-14.0.mu.). The infrared analysis is be be the one accurate measurement of the concentration of PCAH. EXAMPLE V The same equipment, procedure and materials used in Example I were used except the final tobacco blend contained 0.12 percent by weight palladium (added As (NH.sub.4).sub.2 PdCl.sub.6) and 0.75 percent by weight nitrate nitrogen (0.65 percent of which was provided by added magnesium nitrate hexahydrate). This sample, Sample 10, was tested as described in Example I and showed a relative concentration of PCAH of 42 on a weight basis and 46 based on infrared analysis, compared to a value of 100 for the control of Example I. BIOLOGICAL TEST Utilizing conventional cigarette manufacturing devices, approximately 60,000 unfiltered cigarettes were produced for each of the following tabacco blends, (240,000 total cigarettes), which were treated and prepared according to the techniques and materials described in Example I. WEIGHT PERCENT TOBACCO BASED ON TOTAL TOBACCO WEIGHT WEIGHT % UNCUT Pd, ADDED NITRATED SAMPLE STRIP RTS**** http://164.195.100.11/netacg'i/nph-Parser?Sect1=PTO1&Sect2=HIT.../405519 2/13/01