Document zdJY5O3bYadJaXLvbY7qYdd83

office copy DOW CONFIDENTIAL INFORMATION R & D REPORT CXtNUMIKR DOW CHEMICAL U.S.A. LAiOMATOHY REPORT CODE C. k *? HET T2.8-l-13-(2) DATE ISSUED ., PV DEPARTMENT October 28, 1982 LAE* NO. PRQRLEM NO. Health & Environmental Sciences/Toxicology Research Lab. 2.0.4 4,6,1 ,1 ,3 ,0 ,2 THE COMPARATIVE ABSORPTION AND EXCRETION OF CHEMICAL VAPORS BY THE UPPER, LOWER AND INTACT RESPIRATORY TRACTS OF RATS 52 PAGES IN FULL REPORT AUTHOR (* ) William T. Stott, John C. Ramsey and Michael J. McKenna -- Upper respiratory tract (URT) absorption of several compounds with differing water solubilities and potentials to cause lesions of the nasal mucosa was studied in rats. Uptake of propylene glycol monomethyl ether (PGME), PGME ace tate ester (PGMEAc), ethyl acrylate (EA), epichlorohydrin (EPI), styrene (STY), nitroethane (NE), ethylene dibromide (EDB) and methylene chloride (MeCl2) vapors by the isolated URT were compared with the uptake of these compounds by the iso lated lower respiratory tract (LRT) and whole animal. Nearly all PGME, PGMEAc and 30-70% of EA, EPI, STY, NE and EDB were absorbed by the URT. Similar levels were absorbed by the LRT and whole animal except for STY (>90% absorbed). It was estimated that intact animals received between 19% (MeClp) and 47% (PGME) of its total dose via the URT. Further, the dosage per unit surface area of URT was as much as 500 times that of the LRT. This absorption was observed to be quantita tively related to the blood/air partition coefficient of these compounds. Ab sorption of chemical by the URT, however, did not correlate with the ability of compounds to cause lesions of the nasal mucosa. Several predictive pharmacokine tic models were developed for uptake of chemicals by various regions of the res piratory tract. File-*5 72.3-1-13-(2) Photo K-4567-C*!) p V K-ai7-<e><' K-UIO-QS)^ qO 1 conftof.nttai DISTRIBUTION: DEPARTMENT FILES R & D ADMINISTRATION CENTRAL REPORT INDEX - 4 COPIES (566 Bldg. - Midland) form e-4iot printed R-to-o K-ITIS-Offiity K-07'1-(27)W. O0V'- jMBGl-QWV (V }<.--/}> K- ) Distribution 11st Is continued on ttchod ptg. THE COMPARATIVE ABSORPTION AND EXCRETION OF CHEMICAL VAPORS BY THE UPPER, LOWER AND INTACT RESPIRATORY TRACTS OF RATS By: W. T. Stott, J. C. Ramsey and M. J. McKenna Toxicology Research Laboratory Health and Environmental Sciences, U.S.A, Dow Chemical U.S.A. Midland, Michigan 48640 00 gonf*oFNTT THE COMPARATIVE ABSORPTION AND EXCRETION OF CHEMICAL VAPORS BY THE UPPER, LOWER AND INTACT RESPIRATORY TRACTS OF RATS By: W. T, Stott, J, C. Ramsey and M. J. McKenna ABSTRACT Upper respiratory tract (URT) absorption of several compounds with differing water solubilities and potentials to cause lesions of the nasal mucosa was studied in rats. Uptake of propylene glycol monomethyl ether (PGME), PGME acetate ester (PGMEAc), ethyl acrylate (EA), epichlorohydrin (EPI), styrene (STY), nitroethane (NE), ethylene dibromide (EDB) and methy lene chloride (MeCl2) vapors by the isolated URT were compared with the up take of these compounds by the isolated lower respiratory tract (LRT) and whole animal. Nearly all PGME, PGMEAc and 30-70% of EA, EPI, STY, NE and EDB were absorbed by the URT. Similar levels were absorbed by the LRT and whole animal except for STY (>90% absorbed). It was estimated that intact animals received between 19% (MeCl2) and 47% (PGME) of its total dose via the URT. Further, the dosage per unit surface area of URT was as much as 500 times that of the LRT. This absorption was observed to be quantita tively related to the blood/air partition coefficient of these compounds. Absorption of chemical by the URT, however, did not correlate with the ability of compounds to cause lesions of the nasal mucosa. Several predic tive pharmacokinetic models were developed for uptake of chemicals by various regions of the respiratory tract. DOW CONFIDENTIAL DO 1 3646? opnttai. conf T. INTRODUCTION The mucosa of the upper respiratory tract (URT) of rodents has been observed to be a frequent target tissue of inhaled chemicals. Compounds fall Into two general categories; those causing a nonspecific degeneration of epithelium (e.g., ethylene dibromide), and those causing primarily lesions of the olfactory neuroepithelium (e.g., ethyl acrylate) (Nitschke et al_., 1981; Miller et al_., 1980). Unlike the lesions produced by several nonspecific nasal mucosal toxicants (e.g. formaldehyde), lesions of the olfactory epithelium have not been observed to progress to neoplasia. The URT functions as a first line of defense In preventing potentially harmful chemical vapors from reaching the lower respiratory tract (LRT). Described by Brain (1970) as an efficient "scrubbing tower", the URT directs inhaled air into close contact with a mucosa richly supplied with fenestrated capillaries (Swindle, 1935; Proctor and Swift, 1977). Not sur prisingly, the URT has been observed to absorb large amounts of respiratory irritants such as ozone, formaldehyde, mustard gas, acrolein, hydrogen fluoride and sulfur dioxide (Brain, 1970; Feron et al_., 1978; Giddens and Fairchild, 1972; Cameron et al., 1946; Aharonson et al_., 1974; Spiezer and Frank, 1966; Egle, 1972; Morris and Smith, 1982). This absorption is gen erally believed to be related to the water solubility and reactivity of the inhaled compounds (Aharonson et aK, 1974; Morgan and Frank, 1977). In order to better assess the potential human risk of exposure to com pounds causing lesions of the URT mucosa in obligate nasal breathing ro dents, there is a need for additional information regarding; 1) potential DOIOONFIDENMI -2- physicochemical factors controlling chemical absorption by the URT, 2) the relationship of chemical absorption to the development of specific lesions of the URT mucosa, and 3) the role the URT plays relative to the LRT in the absorption of chemicals by the entire respiratory tract. The purpose of the present study was to provide this information in rats for several com pounds of differing water solubilities and potential to cause lesions of the URT (Table 1). fiflWJQNFlDEHIIAL 00 1 3646.4 CONFTDFNTTAl -3- METHODS AND MATERIALS Chemicals. Ethyl acrylate (EA; Lot #EJS 11-9-77; >99% pure) was obtained from Rohm and Haas Co., Philadelphia, PA, nltroethane (NE; Lot #8020-513; >97% pure) was obtained from International Minerals Co., Terre Haute, IN, and methylene chloride (MeClg; Lot #AE411; >99% pure) was obtained from Burdick and Jackson Laboratories Inc., Muskegon, MI. Styrene (STY; Lot #11-30-81), eplchlorohydrin (EPI; Lot #TP-073k), ethylene dibromide (EDB; production grade), propylene glycol monomethyl ether (PGME; Lot #810310-25) and its acetate ester (PGMEAC; Lot #DPC 203-23) were all obtained from the Dow Chemical Company, Midland, MI, and were >99% pure. Animals. ! Male Fischer 344 rats (200-260 g), obtained from Charles River Breed ing Laboratories (Portage, MI) were utilized in all experiments. Animals were pair housed in environmentally controlled rooms (232C, 5015% rela tive humidity, 12 hour photoperiod), fed Purina Certified Rodent Chow (Ralston Purina, St. Louis, M0) and given water ad libitum, and acclimated at least 7 days prior to use. For all experiments rats were anesthetized (60 mg/kg sodium pentobar bital, ip.), were shorn of facial hair, and had their mouths sealed using surcjlcal clips. The level of anesthesia maintained throughout experiments (approximately stage 3, level 2) resulted in respiratory minute volumes of 53_+3 ml /min as determined by plethysmography (Landry et al., 1982). DOW CONFIDENTIAL OO 1.36465 CONFIDENT! Al -4- Procedures. Atmospheres of 75 ppm EDB, 100 ppm EPI, 200 ppm STY, 225 ppm EA, 500 ppm MeCl2 1000 ppm NE, 1000 ppm PGME and 1000 ppm PGMEAc were used in all experiments. These exposure levels represented those reportedly causing URT lesions in rat bioassays (where applicable) and were absorbed by intact animals at rates directly proportional to exposure levels. Concentrations of these compounds were quantitated using appropriate standards with a Varian Model 1500 gas chromatograph (GC) (Palo Alto, CA) equipped with a 1 ml loop injector, a 1 foot SS 1/8 In. ID column packed with 10% Carbowax 1500 on Chromasorb WH-P (Supelco, Inc., Bellefonte, PA) (column temperature varied between compounds) and a flame Ionization detector (20 ml/mln He carrier gas at 180C). Rates of absorption or excretion of the inhalant by an animal were determined upon reaching a constant level using equations (1) or (2) respectively: (a = moles chemical/mole effluent gas; b = moles chemical/mole test atmosphere; c = 1/min flow rate; d = 24.45 1/mole). moles/min absorbed = (b-a)(c) d (1) moles/min excreted (2) DOW COHHOENTUL DO 1.36466. OONFTDFNTTAL -5- ' Absorption of Inhaled compounds by the intact respiratory tract was investigated by exposing individual anesthetized rats in a small, nose-only chamber equipped with a tight fitting polyvinyl chloride (PVC) cuff which was fastened around the animal's snout. Test atmospheres were pumped (Fluid Metering Inc., Oyster Bay, NY) through the nose-only apparatus at a rate of 150 ml/min and then through a flow meter (Gilmont Inc., Great Neck, NY) and to the GC. Absorption and excretion of inhaled chemicals by the isolated URT or LRT of rats were Investigated in double tracheostomlzed, anesthetized rats much as has been described by Morris and Smith (1982) (Dia. 1). The caudal endotracheal tube (PE 200; Clay Adams, New York, NY) extended out of the trachea approximately 1.5 cm, ending inside a 1/8 inch I.D. Y-intersectlon. A gas flow of 150 ml/min was maintained through this intersection Into the GC via Teflon tubing (1/8 in ID). For LRT absorption studies, the gas in take line was attached to a Saran gas bag containing the desired atmos phere. To determine LRT excretion of compounds this end was left open to room air. To determine URT absorption of compounds, the cephalad endotracheal tube (PE 160) was attached to the GC via a flow meter and pump (Dia. 1). A unidirectional 50-60 ml/min or 100-110 ml/min gas stream was thus main tained from the nares (mouth clipped shut) to the trachea. A PVC cuff was firmly secured about the animals snout on one end and attached to a Saran gas bag containing the test atmosphere on the other. To measure excretion DOW CONFIDENTIAL D0 136.467 CONFIDENTIAL -6- of chemicals by the URT the same gas flow was maintained but in the oppo site direction (trachea to nares), the intake was of room air and the out flow to the GC was via a Teflon line in place of the gas bag at one end of the PVC cuff. Using these data, the "dose" of chemical received by the animal via the URT and LRT was estimated using equations (3) and (4) respectively (e = moles absorbed by URT/t; f moles passing into animal/t; g = fraction ab sorbed; t=time). In the normal animal, exposure of the URT to test atmo sphere occurs primarily during inhalation (i.e. approximately one-half the time of exposure), thus the URT "dose" was multiplied times 0.5t. The dose received by the whole animal was also calculated (equation 5): moles absorbed = (f) (g) (0.5t) by URT moles absorbed = (f-e) (g) (t) by LRT moles absorbed = (f) (g) (t) by whole animal (3) (4) (5) To better understand the factors controlling URT absorption of chemi cal vapors, as well as the interrelationship of the Isolated URT, LRT and the intact respiratory system, a kinetic model was constructed to simulate DOW CONFIDENTIAL 00 136468 CONFIDENTIAL -7- the absorption and excretion rates observed in these experiments. The model was based on partitioning of the chemical between blood and air, and the partition coefficient for a given chemical was considered to be identi cal in the URT, LRT and Intact respiratory system. When compound instabil ities prohibited measurement of blood/air partition coefficients, water/air values were substituted (Table 1). In the intact system, absorption of an inhaled chemical by the URT may take place during inhalation and to a less extent during exhalation, thus the model depicting the Intact animal (Dla. 2) contained a "nasal cavity" for each situation (URTI and URTE). Inhaled atmospheres were passed through the URTI first, then the lungs and exited through the URTE. Models describing the uptake and excretion of Inhalants by the URT and LRT con tained only one URT with both the URT and LRT being Independently venti lated, one with test atmosphere (absorption) and the other with air (excre tion) (Dia. 3). The rest of the body (eg. muscle, fat, liver) were lumped into a sin gle compartment equivalent to the volume of distribution of the chemical in rats. Nonresplratory elimination of absorbed chemicals was defined to be equivalent to their central compartment elimination rate constants observed in rats. Physiological constants included; a total cardiac output in pen tobarbital anesthetized rats of 14.8 l/hour<kg (Blood et al_., 1950) of which 1.5% was estimated to perfuse the URT (Stott et al_., 1982) and 98.5% the central compartment; a URT capillary blood volume of 0.052 ml (10% of a DOW CONflDENIMl DO 136469 CONFTDPNTT Al -8- measured total URT blood volume in rats); an estimation of 0.34 ml of cap illary blood in pulmonary tissues (Weibel, 1963); and an effective ventila tion of the respiratory tract (minus anatomical dead space) of 0.7 x 53.2 ml/min. All other constants were maintained as in the intact system. The constants used and computer programs with their differential equations are shown in Appendices I-III. In addition, i.v. blood curves of PGME, PGMEAc, NE and EA are shown in Appendices IV-VII. DOW CONFIDENTIAL DO 1.364-70 CONFIDENTIAL -9- RESULTS Absorption of chemical vapors by the URT, LRT and Intact respiratory tracts of pentobarbital anesthetized rats reached an apparent plateau with in 10 to 20 minutes and remained relatively constant for the duration of exposure. As shown In Table 2, the Isolated URT was observed to absorb over 90% of PGME and PGMEAc and between 50 to 70% of EA, EPI, STY, NE or EDB when these vapors were passed through the URT at a flow rate equivalent to the animals respiratory minute volume (50-60 ml/min). In contrast, MeCl2 was only poorly absorbed (17%) by the URT. Similar rates of absorp tion were observed to occur with the LRT and the intact respiratory tract, with the exception of STY and MeCl2 which were more readily absorbed (>90% and >36% respectively) than in the URT. In general, only a small percentage (<5%) of LRT absorbed compounds wer^ simultanelously excreted via the URT. Likewise, little of the com- I pounds absorbed by the URT were simultaneously excreted by the LRT (<3%) (Table 2). MeCl2 was an exception to this rule, as virtually all MeCl2 ab sorbed by the URT was excreted by the LRT. A constant rate of excretion by the URT and LRT was also observed even though it was doubtful that steadystate blood levels had been attained. Indeed, this was observed in preli minary experiments on PGME excretion, in which pulmonary excretion appeared to remain constant over the same time period in which blood levels of pGME doubled. An explanation of this may be the inability to detect small abso lute changes in chemical vapor concentrations of effluents. DOW CONFIDENTIAL 00 13&A71 CONFTDFiNTTAl -10- An increased URT ventilation rate (100-110 ml/min) was observed to re sult in less than a 5% decrease in the absorption of PGME, PGMEAc and EPI. A larger decrease (25 to 40%) in the absorption of vapors was noted for EA, STY, NE, EDB and MeCl2 (Table 3). Despite this decrease in percent absorp tion, the rate of URT uptake of chemicals was observed to increase for most of the compounds tested, PGME, PGMEAc and EPI were absorbed at rates equi valent to 1.9 to 2.0 times, and EA, STY, MeCl2 and EDB at rates 1.2 to 1.5 times, the rates observed at the slower URT ventilation rate. URT absorbed material was estimated to contribute from 19% (MeCl2) to 47% (PGME) of the total dose of test chemicals received by exposed intact rats (Fig. 1). These estimates were obtained using the URT % absorption data obtained at two times the respiratory minute volumes of these animals, thus approximating the residence times of chemicals passing through the URT. The calculated total dose of a given chemical received by rats (l.e. sum of the isolated URT and LRT doses) was well within the potential exper imental error for that calculated from actual whole animal exposure data. These results, when normalized for a uniform exposure concentration and exposure time, are displayed in Fig. 1. A comparison of the rates of chemical absorption predicted by kinetic models for the three experimental preparations are presented in Table 4. In general, there was good agreement between predicted values and the ex perimentally observed results shown in Table 2. Notable exceptions were DOW CONFIDENTIAL OO 136472 CONFTDENTIAI -li the absorption of MeCl2 by the LRT and intact animals, in which the models overpredicted uptake, and the absorption of EA, EPI and EDB by the isolated URT, in which the model considerably underpredicted absorption. Predicted URT and LRT excretion values were within the range of experimentally ob served values (data not shown). DOW CONFIDENTIAL 136473 CONFIDENTIAL -12- DISCUSSION The results of the present study demonstrate that the URT plays a sig nificant role In the absorption a variety of chemical vapors by rodents. The Isolated, ventlllated URT of anesthetized Fischer-344 rats was observed to absorb nearly all PGME and PGMEAc vapors, and 30-70% of EA, EPI, NE, EDB, and STY vapors passed through them at a ventilation rate equivalent to 1 or 2 times the respiratory minute volume (53 ml/min). The URT appears to play a relatively minor role In the absorption of MeCl2 and in the excre tion of all these chemicals, once absorbed Into the blood stream. To obtain these data, the bidirectional, alternating ventilation of the URT in the intact animal was replaced by the unidirectional, constant ventilation of the Isolated URT. Thus, gradients of vapor concentrations which normally exist between the URT and LRT were disrupted. However, con siderable evidence suggests that these data do approximate normal URT func tion. Unidirectional air flow prevents the loss of absorbed chemicals from the nasal mucous due to solute backpressure normally occurring during exha lation. However, significant backpressure would be expected only with high concentrations of compounds (eg. >1%) with high vapor pressures and low water solubilities, circumstances quite different from those employed here. Preliminary experiments established that there were no appreciable differ ences in URT blood flow between the exposed Isolated URT and the URT of ex posed intact animals, and that no trigeminal nerve reflex mediated changes In respiratory rates occurred in these anesthetized rats. And finally, there was good agreement between the total amounts of chemicals absorbed when calculated as a sum of the isolated parts of the respiratory system and the intact system (Fig. 1). DOW CONFIDENTIAL DO 136474 CONFIDENTIAL -13- The influence of flow rate on absorption of chemical vapors by the isolated URT was also evaluated. As shown In Table 3, a two-fold increase in the flow rate from 53 to 105 ml/min resulted in up to a 40% decrease in the absorption of chemicals. The former URT ventilaton rate utilized re presented the respiratory minute volumes of these animals thus maintaining an equivalent net mass transfer of chemicals in each of the animal prepara tions. The later flow rate resulted in roughly equivalent residence times of vapors in the isolted URT as occurred In the URT of exposed whole ani mals. A similar relationship of URT flow rate and chemical absorption has been discussed by Brain (1970) and Aharonson et al_. (1974). Based upon the above considerations, the chemical dose of PGME, PGMEAc, EA, STY, EPI, EDB and NE absorbed by animals via the URT appears to be quite substantial relative to that absorbed by the LRT in the intact respiratory system, even though the URT is only exposed primarily during the inhalation phase of the breathing cycle (Fig. 1). Furthermore, when absorption is expressed in terms of surface area (Chang et al_., 1982; Bevin et^ al_., 1979), the dose received by the URT is as much as 500 times greater than that of the LRT. Thus, it is not surprising that the reactive com pounds EDB and EPI were observed to effect the respiratory epithelium of the nasal cavity before that of the LRT (Nltschke et al_., 1981; Quast et al., 1979). In these cases the protective role of the nasal mucosa is well illustrated. DOW CONFIDm 00 136475 OONFTDFNTTAl. -14- Simple chemical vapor absorption itself however, does not correlate with the production of morphologic lesions of the URT mucosa. PGME was readily absorbed by the isolated URT yet does not cause these lesions in exposed rats (Miller et al_., 1981a). Likewise, the potential site of acti vity within the URT mucosa of exposed rats does not appear to be related to their URT absorption. Compounds causing primarily lesions of the olfactory epithelium (NE, EA, PGMEAc) were absorbed by the Isolated URT at rates greater or equivalent to those compounds which cause primarily lesions of the respiratory epithelium (EPI, EDB) (Gushow et al_., 1982; Miller et al., 1980, 1981b; Nitschke et al_., 1981; Quast et aU, 1979). The kinetic models utilized to predict chemical absorption by the URT, LRT and intact respiratory tract correctly reflected the dynamics of chemi cal vapor uptake in the exposed rat. Uptake was related to the blood/air partitioning of compounds, but only when used In conjunction with the dis tribution and excretion kinetics of the chemicals. Likewise, a simple cor relation between uptake and water solubilities was not evident. Differ ences in observed and predicted values of chemical vapor absorption were mostly inconsequential and not attributable to any single variable. The large underestimations of URT absorption of EA, EPI and EDB made by the model were not surprising. EA has been observed to be readily hydrolyzed by nasal cavity area esterases in vitro (Stott and Young, 1982), while EPI and EDB are known to undergo metabolic activation and to bind with tissue macromolecules (Rannug, 1980; Fishbein, 1976; Jones et al., 1969). Indeed, MW CONFIDENTIAL DO 136476 CONF T DFNTT AL the nasal mucosa Is well supplied with xenobiotic metabolizing enzyme sys tems (Dahl et al_., 1980; Brlttebo et ]_., 1981). Thus, substantial amounts of these three chemicals may be removed In the URT at a rate faster than physical blood/air partitioning would account for. The overprediction of MeCl2 absorption by the LRT and Intact animal models may reflect a more serious error In the physical and biological constants used or a particular sensitivity to some experimental effect. The data reported here emphasize the role the URT may play In protect ing the lungs from exposure to high concentrations of potentially harmful chemical vapors. However, extensive absorption of vapors by the URT does not indicate that a compound is a respiratory tract toxicant or that It causes lesions of the URT mucosa. It Is expected that mouth breathing by exposed nonobligate nasal breathing animals, including humans, will circum- I vent [this protective role thereby decreasing the dose of chemical received by the URT relative to the LRT. In this situation, compounds causing gen eralized lesions of the respiratory epithelium would be expected to have a greater effect on the LRT epithelium. For example, pulmonary effects have been observed by Andur (1959) to occur in tracheostomized guinea pigs but not in normal guinea pigs exposed to formaldehyde vapors. However, for those compounds causing primarily lesions of the URT olfactory neuroepithe lium, a significant bypassing of the URT in these animals would result in a j decrease in the severity of mucosal lesions. DOW CONFIDENTIAL W x bA ZMCnOoNFT3DEN7T TAl -16- ACKNOWLEDGEMENTS The authors wish to express their appreciation to P. E. Kastl for ex cellent technical assistance and to Drs. R. R. Miller and R. J. Nolan for their support and insight into the conduct of these experiments. Written by: Dipl ornate, American Board of Toxicology Senior Research Toxicologist Toxicology Research Laboratory 26 acrei. Board of Toxicology Research Leader Toxicology Research Laboratory __- i* // l- /r^ M. vK McKenna, Ph.D. Dipiomate, American Board of Toxicology Research Manager Toxicology Research Laboratory Reviewed by: y.f) 31 fat- R. J. Nolan, Ph.D. Dipiomate, American Board of Toxicology Project Leader Toxicology Research Laboratory OOWJHNFIDENTIAL DO 136478 CONFIDENT! Al -17- TITLE OF STUDY: THE COMPARATIVE ABSORPTION AND EXCRETION OF CHEMICAL VAPORS BY THE UPPER, LOWER AND INTACT RESPIRATORY TRACTS OF RATS - HET T2.8-1-13-(2) In compliance with Good Laboratory Practice Regulations, the study phases were inspected by the Quality Assurance Unit and the results of these in spections reported to Management and the Study Director on the dates listed below. The report accurately reflects the data generated in accordance with the regulations and Standard Operating Procedures of the laboratory. All data and the reports are located at the submitting laboratory. Study Started: 21 Dec. 1981 Report Issued Date: 28 October 1982 Dates of Inspection: 21 Dec, 1981 Date of Report: 21 Dec. 1981 19 Feb. 1982 23 Feb. 1982 8 March 1982 8 March 1982 13 October 1982 14 October 1982 Quality Assurance Toxicology Research Laboratory Health & Environmental Sciences 1803 Building Dow Chemical U.S.A. Midland, MI 48640 DOW CONFIDENTIAL 00 1.36A79 CONFTOEr NTT A* -18REFERENCES Aharonson, E. F., Menkes, H., Gurtner, G., Swift, D, L. and Proctor, D. F. (1974). Effect of respiratory airflow rate on removal of soluble vapors by the nose. J. Appl. Physiol 37, 654-657. Amdur, M. D. (1959). The physiological response of guinea pigs to atmos pheric pollutants. Int, J. Air. Poll, _1 170-183. Bevin, W. S., Crawford, M. P. and Brewer, N. R. (1979). Morphophysiology. In The Laboratory Rat, (H. J. Baker, J. R. Lindsey and S. H. Weisbroth, eds.), Vol. 1, pp. 74-104, Academic Press, New York. Blood, F. R., Smith, D. L. and D'Amour, F. E. (1950). Cardiac output in the rat at normal and at high altitudes and Its relationship to gas embolism. Am J. Physiol. 163, 268-271. Brain, J. D. (1970). The uptake of Inhaled gases by the nose. Ann. Otol. Rhino!, Larygol. 79, 529-539. Brlttebo, E. B. and Tjaelve, H. (1982). Tissue-specificity of n-nitrosodibutylamine metabolism in Sprague-Dawley rats. Chem-Biol. 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The pharmacokinetics of inhaled methylene chloride in rats. Proc. Ninth Ann. Conf. Environ. Toxicol., Dayton, OH, 1979, AMRL-TR-79-68. pp. 184-205. Miller, R. R., Ayres, J. A. , Calhoun, L. L., Young, J. T. and McKenna, M. J. (1981a). Comparative short-term inhalation toxicity of ethylene glycol monomethyl ether and propylene glycol monomethyl ester in rats and mice. Toxicol. Appl, Pharmacol. 61, 368-377. Miller, R. R., Ayres, J. A., Rampy, L. W., Smith, J. M., Weil, C. S., Clary, J. J. and Jersey, G. C. (1980). Ethyl acrylate vapor inhalation study: 3 month sacrifice of rats and 6 month sacrifice of rats and mice. Presented at the 19th Ann. Mt, Soc, Toxicol., Washington, D.C. March 9-13, Abstr. 159. Miller, R. R., Ayres, J. A. and Young, J. T. (1981b). Dowanol PM Acetate Results of a 9-day vapor inhalation study with rats and mice. Report of the Dow Chemical Company, Midland, MI. Morgan, M. S. and Frank, R. (1977). Uptake of pollutant gases by the res piratory system. In Respiratory Defense Mechanism. (J. D. Brain, D. F. Proctor, L. M. Reid, eds.), pp. 157-189. Marcel Dekker, Inc., New York. Morris, J. B. and Smith, F. A. (1982). Regional deposition and absorption of inhaled hydrogen fluoride in the rat. Toxicol. Appl, Pharmacol. 62, 81-89. Nitschke, K. D., Koclba, R. J., Keyes, D. G. and McKenna, M. J. (1981). A thirteen week repeated inhalation study of ethylene dibromide In rats. Fund, Appl. Toxicol. 1, 437-442. Proctor, D. F. and Swift, D. L. (1977). Temperature and water vapor ad justment. In respiratory defense mechanisms (J. D. Brain, D. F. Proctor and L. M. Reid, eds.), pp. 95-124, Marcel Dekker, Inc., New York. NMMDQim 00 136481 CONFIDENT! Al -20- Quast, J. F., Henck, J. W., and McKenna, M. J. (1979). A 90-day inhala tion toxicity study of eplchlorohydrin in laboratory rodents. Presented at 18th Ann. Mt. Soc. Toxicol., New Oreleans, LA, March 11-15, Abstr. 85. Rampy, L. W,, Nitschke, K. D., Bell, T. J. and 8urek, J. 0. (1979). Inte rim results of two-year inhalation toxicologic studies of methylene chloride In rats and hamsters. Presented at 18th Ann. Mt. Soc.Toxicol., Ramsey, J.C. and Young, J. D. (1978). Pharmacokinetics of inhaled styrene In rats and humans. Scand. J. Work Environ. & Health 4 (Suppl. 2), 8491. Rannug, U. (1980). Genotoxic effects of 1,2-dibromethane and 1,2-dichloroethane. Mut, Res. 76, 269-295. Reznik, G., Stinson, S. F. and Ward, J. M. (1980). Respiratory pathology In rats and mice after inhalation of l,2-d1obromo-3-chloropropane or 1,2-dibromoethane for 13 weeks. Arch. Toxicol. 46, 233-240. Sato, A. and Nakajlma, T. (1979). A structure-activity relationship of some chlorinated hydrocarbons. Arch. Environ. HIth. 34, 69-75. Smith, F. A. Young, 0. D., Langvardt, P. W. and Braun, W. H. (1982). Pharmacokinetcs of epichlorohydrin administration to rats by gavage or Inhalation. (Manuscript In preparation). Spiezer, F. E. and Frank, N. R. (1966). The uptake and release of SO2 by the human nose. Arch. Environ. Hlth, 12, 725-728. Stott, W. T. and Young, J. T. (1982). Investigation of esters causing lesions of the nasal olfactory neuroepithelium. (Manuscript in prepara tion). Stott, W. T., Dryzga, M. D. and Ramsey, 0. C. (1982). Blood flow distri bution in the mouse as compared to the rat. Am. J. Physiol. (Submitted). Swindle, P. F. (1935). The architecture of the blood vascular networks in the erectile and secretory lining of the nasal passages. Ann. Otol, Rhino!. Laryngol. 44, 913-932. Weibel, E. R. (1963). Morphometry of the Human Lung, Academic Press New York, MWJMlFIOmiAL I TABLE 1 Physical and Biological Data Water Solubility Compound (ppm) P6ME PGMEAc 200,000 EA 2,000 EPI 60,000 STY 330 oo O NE ZTt 3 no r--"( ^ O3 m 0s EDB z -A 503; 4,000 ,-f 00 5. MeCl2 13,250 Partition Coefficient3 (Blood or Water/Air) 403 (B) 141 (W) 2.3 (W) 11 (W) 39 (B)d 21 (B) 3.9 (B) 9.7 (B)f Central Compartment Excretion Constant*1 (hr-1) 0.23 4.9 15.8 0.16c 2.7d 1.7 1.8e 10.69 Volume Distribution*1 (JO Reported Lesions of the URT Mucosa of Exposed Rats 0.91 No Visible Lesions (Miller et aK, 1981a) 1.01 Degeneration Olfactory Epithelium (Miller et al_., 1981b) 0.36 Degeneration Olfactory Epithelium (Miller et aK, 1980) 0.35c 1.15d Degeneration Respiratory Epithelium (Quast et al., 1979) No Visible Lesions (Jersey et aK, 1978) rH,o* 1 0.16 Degeneration Olfactory Epithelium (Gushow et aK, 1982) 0.23e Degeneration Respiratory Epithelium (Nitschke et al., 1981; Reznik et al., 1950) 0.309 No Visible Lesions (Rampy et a_K, 1979) aDetermined experimentally at 37C In a 100 ml sealed vial containing 5 ml whole heparinized blood or distilled water unless noted by footnote. (B) = blood; (W) = water. ^Determined experimentally upon i.v. administration to rats (blood concentration curve analysis) unless noted by footnote. cSmith (1982). dRamsey and Young (1978). The rate constant is based on the rapid () distributive phase. eWatanabe and Fox (personal communication). fSato and Nakajima (1979). 9McKenna (1979). DOUTCONFIDENTIAL d -22- TABLE 2 Absorption and Excretion of Chemical Vapors by the Isolated URT, LRT and by the Intact Respiratory Tract of Ratsa Compound PGME PGMEAc EA EPI STY NE EDB MeCl g TJTTT 94 0.05 92 0.41 68 5.9 65 9.1 62 8.2 62 5.9 50 1.8 17 1.8 % Absorption^ LRT 106 7.3 99 38 61 8.6 73 8.6 94 3.6 71 5.0 51 17 37 4.1 Intact 87 6.8 85 12 65 7.3 51 7.7 92 9.5 58 12 58 9.1 44 10 % Excretion0 URT DTI 0.2 0.5 0.1 0.6 3.8 2.8 3.6 0.2 1.7 1.8 0.2 0.8 ND ND 4.5 0.9 5.0 0.4 2.8 2.0 2.0 0.4 ND ND 4.8 100 3.8 16 aAverage +_ standard deviations of 4-8 animals ^Absorption expressed as a % of chemical available for absorption at a ventillation rate of 53 ml/min. cExcretion expressed as a % of absorbed chemical. ND * None Detected. DOW CONFIDENTIAL fiDaO& -23- TABLE 3 Absorption of Chemical Vapors by the Isolated URT at 1 and 2 Times the Respiratory Minute Volumes in Rats Compound PGME PGMEAc EA EPI STY NE EDB MeCl g % Absorption^ 50-60 ml/min flow 100-110 ml/min flow 100 0.05 100 0.05 99 0.5 97 2.3 68 6.4 42 11 54 6.4 51 4.5 52 1.8 33 5.0 70 1.8 52 1.4 48 3.2 32 5.0 10 2.3 6 2.7 Ratio* 1.0 0.98 0.62 0.94 0.63 0.74 0.67 0.60 Average +_ standard deviations of 3 rats. ^Absorption expressed as a % of chemical available for absorption. cPercent absorption at 110-110 ml/min divided by percent absorption at 50-60 ml/min. DOW CONFIDENTIAL DO 136485 CONFTDENTTAl -24- TABLE 4 Predicted vs. Observed Values for Chemical Absorption in Rats3 Compound PGME PGMEAc EA EPI STY NE EDB MeCl 2 --urn------ 99 85 7.3 29 77 50 16 111 onPercent of Experimental Value --------- Intact Respiratory Tract 94 115 100 116 113 106 80 111 104 105 104 123 81 66 240 198 3Values are presented as a % of experimental values = predicted x 100 observed DOW CONFIDENTIAL Dia. 1. Ventral view of animal preparation used to determine absorption of chemical vapors by the URT and simultaneous excretion of absorbed com pounds by the LRT. DOWJONFIDENTIAL DO OONF -26- DOW CONFIDENTIAL nn l3f>488 , confidential- -27- Dia. 2. Schematic of kinetic model of uptake of chemical vapors by the whole animal. Abbreviations: Q, respiratory minute volume; QC, total car diac output; Cl, concentration of chemical vapor going to LRT; CP, concen tration of chemical vapor exiting LRT; CX, concentration of chemical vapor in exhaled atmosphere; K10, central compartment excretion constant. I 00W CONFIDENTIAL 00 136489 rONFlOFNTTAl. -28- Excretion DOW CONFIDENTIAL 00 136490 OONF T OF NTI Al. -29- Dia. 3. Schematic of computer model of URT and LRT absorption and si multaneous excretion of chemical vapors. Abbreviations are as In Dia. 2 plus; CIP, concentration of chemical vapors entering the LRT. For URT ab sorption and LRT excretion of chemical vapors Cl = test atmosphere and CIP = room air. For LRT absorption and URT excretion of chemical vapors Cl = room air and CIP * test atmosphere. DOWJONFIDENriAL DO CONF lDENTtA" -30- Excretion OOWJHNFIDU no 136492 COMFTOF.NTTAl- Fig. 1. Comparison of calculated doses of chemicals received via the isolated URT, LRT and intact respiratory system. All data were normalized to a l^amole/min equal time exposure. DOW CONFIDENTIAL s LRT URT Whole Animal EDB MeClj SOtflCONflDENTIAL NSXSX> 136494 C O N F ID E N T IA L -33- APPENDIX I. Computer program used to estimate uptake of chemical vapors by the whole animal. DOWJJONFIDENTIAL oo tdfnttai C.ONF -34- c <>00000i 0 PROGRAM 00000011 1 00000012 I 00000013 1 GPETAC *ACSLjDYNAMIC GAS EXCHANGE MODEL WI' METABO LISM AND TISSUE UPTAKE - INHAL EQUII MODEL - WHOLE ANIMAL EXPOSSURE - RATS 00000061 00000062 INITIAL c 00000063 00000064 ' 'QI - TOTAL AIR FLOW RATE CL/HR) 00000065 CONSTANT c 00000066 =00000067 =00000068 CONSTANT c 00000069 QI = 9*0 1 QMV MINVOL' QMV 3*192 00000070 c 00000071 00000072 Constant ' =Q ALVEOLAR VENTILATION RATE (L/HR)' Q = 2*234 00000073 00000074 c 00000075 CONSTANT ` =QC CARDIAC OUTPUT (L/HR)' =QC 3.4 00000076 00000077 c 00000078 CONSTANT ='QU CARD OUTPUT AT 1.5ZQC' QU = 0.051 00000079 c 00000080 00000081 CONSTANT =QR CARD OUTPUT RESERV1 =QR 3*298 00000085 c 00000086 00000087 CONSTANT c'* 00000083 V n.r.r, 00039 ( CONSTANT r. r, p. o o 91 ' =VR VOL RESERVOIR' =VR .001 ' !C = 1ST ORDER RATE 1C K = *001 ' VBC~ ym_ '.C" C7 0 1 ;V;Y BLOOD IN LUNGS 00000092 CONSTANT VBP= 0*00034 ( 00000100 00000110 ' VBU = VOL BLOOD IN URT <L>' c 000001 1 1 CONSTANT 000001 1 2 0 00 01 1 3 VBU- 0.000052 ' PB = BLOOD-TO-AIR PARTITION COEFFICIENT 00000114 CONSTANT c 00000115 PB = *001 00000130 01} 0 0 0 2 0 0 CONC = CONCENTRATION IN CHAMBER AIR (MG/L t 00000300 CONSTANT CONC = 0.001 00000310 C0000500 'TIMING COMMANDS 1 ( 00000600 ''000610 CONSTANT TCMNG =: 6 * 0 00000700 ronSTmNT IS TCP " 2 * c OOOOOGOO CONSTANT 101 NTS - 120.0 00000900 Cl NT - TSTOP/POINTS 00001 GOO l O' ! 0 01 1 0 0 END 0 0 0 01 20 A T 'END Or INITIAL' i K. o:-')0(300 DYNAMIC 0000 i 4 ' o.-'.oc-'io alonr;: thm ;alg = 2 0-' : 0 i 1 1 oofti v.v ive 0 0`"'1 4 l 2 0 0 \ a * rt CY ~ MEASURED AIR CONCENTRATION (MG/L)1 oooo* ;i4 C Y - < C X * Q M V CI -w ' 0 T - CM'..') ) / 01 AOCM 4* 3 0 c 416 Cl = CGNCE >!TRA71 ON IN INHALE!: AIR (MG/L)' 00 136496 OONFTDFNTTAl r 60001417 G000141S =Cl C0NC#<1.0 -35STEP (TCHNG) ) 60001505 r 00001506 60001509 'TMASS = ABP+ABUE+ABUI+AR+AX+AM TMASS = 60001510 r .6000151 1 00001512 =('CV PO CV 60001513 c 60001514 00001515 DIF = 60001516 c 00001517 60001518 'DOSE = 60001519 c 60001530 DOSE = 60001540 00001550 c 600A< 560 60001570 'ABU I RABUI ABU I AHT IN BLOOD URT INSPIRATION' Q*(CI-CVUI/PB> + G)U* (CA-CVIJI) INTER f P'ABUI, 0*0) 60001580 c 00001590 60001600 CU CVUI/PB CVUI ABUI/VBL) 60001700 c 00001800 -30001 900 'ABP RABP '--'BP AHT IN BL LUNG ' Q*< CU - CA/PB) * QC*<CV-CA) INTCG-IRABP, 0*0) s 90002000 c 60002001 S' 60002002 CP CA/PB CA ABP/VBP ( 00002003 60002004 G0002005 'ABUE RABUE ABUE AHT IN BL URT EXHALATION' Q*(CP-CVUE/PB) +QUw(CA-CVUE) INTEG(RABUE, 0*0) 60002007 CX CVUE/PB C 00002003 00002010 CVUE= ABUE/VBU 00002300 c 00002941 00002942 'AM = AMOUNT METAB (MG)' 00002943 (. 30002944 RAH = K * AR AH = INTEG (RAM, 0.0) 00002945 00002946 c 00002947 'RAR = RATE AMT CHANGE IN RESERVOIR RAR = QR*(CA ~ CVR)- RAH 00002943 AR = INTEG (RAR, 0,0) 60002749 c 00002950 CVR= AR/VR 30002960 `AX = AMOUNT EXHALED (HG)' 30002970 c 00002930 60003200 RAX = Q*CX AX = INTEG(RAX, 0.0) 30004000 c 30004100 'AT = AMT INI-I TO URT' 60004200 RAI == Q*CI 30004300 AI = INTEG (RAI, 0.0) 00004310 30004300 30005000 00005300 TERMT(T.GT.T"TOR) 60005310 60005320 PREP AR ( T , CY , Cl, RABIJI , ABU I . CU , CV , RABUE L 60005330 ABUE , CX , CA, RmBP , ABP , CP, RAM . AM, k'AR, AR j * * * 00005400 RAX, AX,RAI,AI,THASS,DOSE,CVR,PB,QMV , 136497 DO CONF TDENTIAL -36- <V 99005410 CVUI,CVUE,DIF) 00005500 END $'END OF DERIVATIVE' ... G0OQ5510 0005600 09005700 END $1 END OF DYNAMIC 3005800 0 00005900 END $'END OF PROGRAM' C c c c c c & c= c c c O c c r now mmmtAi c k 00 136498 OONFTDFNTTAl. -37- APPENDIX II. Computer program used to estimate URT uptake and LRT ex cretion of chemical vapors. DOW CONFIDENTIAL 136499 DO C.OHF -3b- 00000010 PROGRAM: GBETAD.ACSLjDYNAMIC GAS EXCHANGE MODEL WITH SAT'JRABLE 00000011 METABOLISM AND TISSUE UPTAKE - INHAL EQUILIBRATION 00000012 00000013 i MODEL - URT ABSDPTION / LRT EXCRETION IN RATS 00000061 00000062 INITIAL 00000063 00000064 1QI = TOTAL AIR FLOW RATE (L/HR)' 00000065 CONSTANT QI = 9-0 00000066 00000067 1QMV=MIN VOL' 00000068 CONSTANT QMV= 3.192 00000069 00000070 'Q = VENTILATION RATE (L/HR)' 00000071 CONSTANT Q = 2.234 00000072 00000073 'QC - CARDIAC OUTPUT (L/HR)' 00000074 CONSTANT QC = 3.4 00000075 00000076 QR = CARDIAC OUTPUT TO RESERVOIR1 00000077 CONSTANT r 00000078 QR = 3.349 00000079 "QU = CARD OUTPUT AT 1.5JCQC' 00000030 CONSTANT c. 00000085 QU = .051 00000036 'VR = VOL RESERVOIR' c 00000087 CONSTANT 00000038 VR = .001 00000039 'K = 1ST ORDER RATE K1 l 00000090 CONSTANT 00000091 K = .001 1VBP= VOLUME OF CAPILLARY BLOOD IN LUNGS <L)` 00000092 CONSTANT VBP- 0.00034 00000100 c p 0^ 0 '7BU = VOL BLCOO IN URT (L)1 00"00*1 1 CONSTANT VBU*.000052 000001 1 2 c ri'Hflflf!< * T 1PB = BLOOD-TQ--AIR r'4r:'T'!"r'rnw ' 000001!4 CONSTANT PB = .001 00O00115 c 00CO0130 OG000200 'COMC = CONCENTRATION IN CHAMBER AIR (MG/L)' O'*0 00300 CONSTANT CONC =0.001 c 0 O' 0 0310 00000500 'TIMING COMMANDS' 00000600 t 00000610 CONSTANT TCHNG = 00000700 CONSTANT TSTOP = 6.0 2.0 0 00 00 SO10 CONSTANT POINTS = 120.0 c 0000'"'? 00 ClNT = T ST OP/POINTS 0000i000 00 "01 1 00 END *'END OF INITIAL' c 00001200 00001300 DYNAMIC 001 400 AAA \ J. * A ALGORITHM IALG = 2 '`00 : Vi 1 ''001 41 2 DERIVATIVE 00 136B00 CONFIDENTIAL c 0 >0001 -1 4 ' * ) ' 4 1 5 MEGS CQNC AT 0 15 LPM' "O./" ;ijj = cqmv*cf*- Q.I-QMV) ) /QI L now confideotmiccncentr-:'Tic11 in inhaled air <mc;/ -39- r OOOo 1 4i 9 03001420 CI = CONC* (1*0 - STEP ( TCHNG 00001-138 r kr 00001439 00001444 TMASS = ABP+ABU+AR+AXP+AM+AXU 00001445 TMASS = MASS BALANCE (MG)1 r 00001446 00001447 00001448 1 DOSE = NET AMOUNT ABSORBED (MG)' r 00001449 00001450 DOSE = AI+AIP-AXP-AXU 00001460 c 00001510 00001540 Vr. 00001550 00001560 ABU = AMT IN BLOOD URT ' RABU= Q#(CI-CVU/FB) + QU(CA-CVU) 00001570 ABU = INTEG(RABU, 0*0) r V 000015S0 00001590 CU = CVU/PB CVU = ABU/VBU 00001600 A 00001700 00001800 ' ABP = AMT IN BL LUNG ' RABP = Q#(CIP - CA/PB) + QCw(CV-CA) 00001900 ABP = INTEG(RABP, 0.0) 00002000 r 00002001 CP = CA/PB CA = ABP/VBP 00002002 * 00002003 00002004 POOLING OF CV1 CV = (QR*CVP + QU*CVU)/QC 000020^0 AQAA.?7,O0 00002941 00002942 AM = AMOUNT METAB (MG)' ,# - 00002943 , *_ 00002944 00002945 1 RAM K * AR AM = INTEG (RAM, 0.0) r* 00002*46 00002747 AR AMT TN RE.r'ERVC'IR' PA'". - SR.'v'CA - 3 V R ) - ".A,' 00002948 AR a INTEG (EAR, 0.0) 00002949 CVR = AR/VR - 00002950 00003200 00003300 ' AXLJ = AMT EXH FROM URT1 00003400 RAXU= Q#CU 00003500 AXU = INTEG (RAXU, 0.0) 00003600 te 00003700 ' AXP = AMT EXH PLJI..M1 00003800 RAXP = Q*CP 00003900 AXP INTEG (RAXP, 0.0) ' 00004000 I 00004100 1 1 AI - AMT INH TO URT' 00004200 RAI=Q*CI 00004300 AI - INTEG (RAI, 0.0; 00004310 00004320 A IP = AMT INH TO PULM' 00004330 RAIP a Q*CIP 00004340 00004341 AIP = INTEG(RAIP, 0.0) CIF = 0.00000000001 00 1.36501. CONFIOFNTTAL 00004350 00004800 00005300 TERMT(T.GT.T STOP) 00003310 DOW CONFIDENTIAL00005320 PEEPAR CT,CI, RABU,CV,ABU,CU,CVR,CIP,DOSE,... & 00005330 CA , RABP , ABF', CP , RAM, AM , R'AR .. AR , . . . 00005400 RAI,AI, TMASS, DOSE , CY , F'B , QMV , * * . 00005410 RAXU, AXU , RAXF', AXF', RAIP, AIR , CVU ) & 00005500 END 00005510 t'END OF DERIVATIVE1 00005600 0 00005700 END 00005300 VEND OF DYNAMIC 00005900 END VEND OF PROGRAM' t c c c c c c* <y c G> c c o c c c DOW CONFIDENTIAL no 3^,507 OENtT AV- CONF T -41- APPENDIX III. Computer program used to estimate LRT uptake and URT ex cretion of chemical vapors. DOW CONFIDENTIAL 00 136503 CONFTOFNTTAl -42- r 00CO0010 PROGRAM: 0OOOOO11 1 00000012 1 00000013 1 GBETA * ACSL; DYNAMIC GAS EXCHANGE MODEL WITH SATU METABOLISM AND TISSUE UPTAKE - INHAL EQUILIBEATI MODEL - LRT ABSORPTION / URT EXCRETION - RATS 00000061 00000062 INITIAL c 00000063 0O0O0O64 00000065 CONSTANT 1 QI = TOTAL AIR FLOW RATE (L/HR)' GI = 9.0 c 00O0OO66 00000067 ' QMV =MIN VOL1 OO00O063 CONSTANT QMV = 3.192 c 00000069 OO0O007O Q VENTILATION RATE (L/HR)' OOOOO071 CONSTANT c 0O0O0O72 0G000073 0. = 2.234 QC = CARDIAC OUTPUT (L/HR)' O000O074 CONSTANT c OOO00073 00000076 QC = 3.4 1 QR = CARDIAC OUTPUT TO RESERVOIR' OO00OO77 CONSTANT c 00000073 0O00OO79 QR = 3.349 'QU = CARD OUTPUT AT 1.57.QC' c 03000030 CONSTANT 00000035 0300"36 c 0OO0OOS7 CONSTANT r^r-a a a qg r 33O00039 cv ""7A009Q CONSTANT ' ' A ft ft CM 0-000092 CONSTANT QU = .051 ' VR = VCL RESERVOIR' VR = .OOl K = 1ST ORDER RATE !< ' !< = .001 ' VBP = VOLUME OF CAPILLARY BLOOD IN LUNGS (L) ' VBP = 0.00034 O00O0100 c 0 70001 1 0 1VBU = VOL BLOOD IN URT <L)' 00001 1 1 CONSTANT VBU-O.000052 30000112 c A 70001 1 3 'PB = BLOOD-TO-AIR PARTITION COEFFICIENT' OOOG0114 CONSTANT RB = .001 '0001 1 5 c O0OO0130 . 0OOO200 1 CONC = CONCENTRATION IN CHAMBER AIR (MG/D c C00O0300 CONSTANT CONC = 0.001 -0000310 GOoO0500 'TIMING COMMANDS' ','0 OO c >"70061 G CONSENT "''AMT -rr'iMr - ,v f '' '*1 r*' ` pni'^TMiT C> H T M T *** -- ^ ^ 0 ^ 0 r.y.riA'j cmi = ''7' 7 "001 < 00 END $ ' END OF INITIAL' C 3 D01230 '000 i 300 DYNAMIC C0001400 ' 0 001 410 ALGORITHM IALG 'DOI 4i 1 O.."0O1 41 2 DERIVATIVE 00 136504 CONFIDENTI Al C -'0301 414 D00D15 0'001 -ii 6 3 0O01H7 DO >14 12 'CY-MEAS CONC AT 0.iGLPM1 COY - CMV* C P + CIP <( ' QI -- Q M V > 1 / GJI DOW CONFIDENTIAL -43- c 0000141? 00001420 'CIP= CIP= 00001430 r 00001433 00001439 00001444 TMASS - ABP+ABU+AR+AXP+AM+AXU f 00001445 00001446 1TMASS = MASS BALANCE (MG)' 00001447 c 00001448 00001449 'DOSE = NET AMOUNT ABSORBED (MG)' DOSE = AI+AIP-AXP-AXU 00001450 c 00001460 00001510 00001540 c 00001550 'ABU 00001560 RABU 00001570 c 00001580 ABU CU 00001590 CVU 00001600 c 00001700 ' ABP = AMT IN BL LUNG ' 00001800 RABP = G)#(CIP - CA/PB) + G>C*(CV-CA) 00001900 c 00002000 00002001 ABP CP CA = INTEG(RABP, O.O) = CA/PB = ABP/VBP s 00002002 >c 00002003 00002004 'PO CV 00002010 c 00002300 00002941 00002942 c 00002943 'AM = AMOUNT METAB (MG)' RAM = K * AR 00002944 AM = INTEG (RAM, 0.0) 00002945 c 00002946 'AR = AMT IN RESERVOIR' 00002947 RAR OR#(CA -CVR) - RAM 00002948 c 0000294? AR = INTEG (RAR, 0.0) CVR = AR/VR 00002950 00003200 ( 00003300 'AXU = AMT EXI-I FROM URT' 00003400 RAXU =; Q#CU c 00003500 00003600 AXU = INTEG (RAXU, 0.0) 00003700 ' AXP = AMT EXI-I PULM' f 00003800 00003900 RAXP :~ QCP AXP = INTEG (RAXP, 0.0) 00004000 00004100 ' AI = AMT INH TO URT' c 00004200 RAI - Q#CI 00004300 AI = INTEG (RAI, 0.0) 00004301 Cl - 0.00000000001 00004310 00004320 ' A I P := AMT INH TO PULM' 00004330 RAIP *= G)#CIP L 00004340 A IP != INTEG(RAIP, 0.0) 00004350 00004300 00005300 TERMT < T . GT . T, 00005310 OOW.DONFiOENriAl . 3f,B06 DO C.ONP C* -44- o 00005320 PREPAR(T,CI,RABU,CV, ABU,CU,CVR,CIP,DOSE, - * - 00005330 CA,RABP,ABP,CP,RAM,AM,RAR,AR, . * * 00005400 RAI,AI,TMASS,DOSE,CY,PB,QMV,... % 00005410 RAXU,AXU,RAXP,AXP,RAIP,AIP,CVU) 00005500 END $'END OF DERIVATIVE' 00005510 00005600 00005700 END $'END OF DYNAMIC' 00005800 c 00005900 END %'END OF PROGRAM' c c c c c c c c o c c 00 136506 r . CONFIDENTIAL DOIOONFIDENTIAL f -45- APPENDIX IV. Plasma decay curve of 10 mg/kg EA administered intravenously in rats. Calculated constants were: volume distribution = 363 ml; K10 0.259/min K12 * 0.0657/min; K21 = 0.0204/min; t 1/2 alpha = 2.10 min; t 1/2 beta = 43.1 min. I DOW CONFIDENTIAL DO 130507 CONFIDENTIAL TIME APPENDIX V. Plasma decay curve of 10 mg/kg NE administered intravenously in rats. Calculated constants were: volume distribution * 155 ml; K10 * 0.0278/min; K12 = 0.393/min; K21 = 0.123/min; t 1/2 alpha 1.29 min; t 1/2 beta = 109 min. DOW CONFiDENHAl 00 136509 CONFIDENTIAL -48- *)b DOW.COHFIOEHTU1 00 l 36^1-0 ' -49- APENDIX VI. Plasma decay curve of 10 mg/kg PGME administered intrave nously in rats. Calculated constants were volume distirbution * 907 ml; K10 = 0.00384/min; K12 = 0.0376/min; K21 = 0.0824/min; t 1/2 alpha = 5.72 min; t 1/2 beta = 266 min. DOW CONFIDENFUU DO 13651.1 CONFIDENTIAL os- t> CO NFIDENTIAL -51- APPENDIX VII. Plasma decay curve of 50 mg/kg PGMEAc administered intra venously in rats. Calculated constants were: volume distribution = 1011 ml; K10 = 0.0810/min; K12 = 0.213/min; K21 = 0.0289/min; t 1/2 alpha = 2.20 min; t 1/2 beta = 93 min. I DQW..CQNFIDEM1AI DO 136513 OONFTDFNTTAl. 1b TIME