PESTICIDE RESIDUES IN FOOD - 1984 Sponsored jointly by FAO and WHO EVALUATIONS 1984 The monographs Data and recommendations of the joint meeting of the FAO Panel of Experts on Pesticide Residues in Food and the Environment and the WHO Expert Group on Pesticide Residues Rome, 24 September - 3 October 1984 Food and Agriculture Organization of the United Nations Rome 1985 PROPAMOCARB Identity Chemical: (IUPAC and C.A.): Propyl 3 - (dimethylaminopropyl) carbamate hydrochloride Synonyms: PrevicurRN, Prevex, Filex, Banol, Dynone N, Schering Code No. SN 66752 and ZK 66752 Structural formula: CH3 O \ " N - (CH2)3 - NH - C - O - C3H7 HCL / CH3 Molecular formula: C9H21 Cl N2 O2 Other information on identity and properties Molecular weight: 224.7 State: A colourless crystalline solid (technical propamocarb hydrochloride) with faint aromatic odour and strong hygroscopic properties Melting point: 45 - 55°C Vapour pressure: 6 × 10-6 Torr at 25°C Dissociation constant (pKa): 9.1 Octanol/water partition coefficient: 2.5 × 10-3 Solubility (at 25°C): >700 g/l in water; >500 g/l in methanol; >430 g/l in methylene chloride; >300 g/l in isopropanol; 23 g/l in ethyl acetate; <0.1 g/l in toluene and hexane Stability: Propamocarb is very stable to hydrolysis. Even at pH 14 the half-life is five days. At pH 9, the half-life is calculated to be 1.3 × 103 years, increasing at pH 5 to 1.3 × 107 years. The product is stable at 55°C for over two years, and to light, even on the addition of acetone. Specification of The technical material has a purity in excess technical material: of 95 percent with the main impurities being N, N - dimethyl - 1 - 3 - diaminopropane dihydrochloride (max. 5 percent), N, N, - bis - (3 - dimethylaminopropyl) urea dihydrochloride (max. 2%) and solvents (max. 1%). Note: Unless otherwise indicated, the studies reviewed in this monograph were conducted with Previcur N, an aqueous formulation of technical propamocarb hydrochloride containing approximately 65 - 70% of the active ingredient (a.i.). For the purpose of identification a 70% aqueous formulation of propamocarb hydrochloride as used in the text of the monograph is synonymous with Previcur N. Unless otherwise specified, the dosages used in the studies are expressed in terms of the formulation. Effects on Enzyme and Other Biochemical Parameters In vitro Plasma specimens from dogs and rats were separately incubated in vitro with technical propamocarb hydrochloride or a 70% aqueous formulation of propamocarb hydrochloride at concentrations, expressed as the technical material, ranging from 0.925 to 74 mg/ml plasma. Significant dose-related inhibition (22 - 60%) of both rat and dog plasma cholinesterase was noted following incubation with either technical or formulated propamocarb hydrochloride at plasma concentrations of 37 mg propamocarb hydrochloride/ml and above. This concentration corresponded to approximately 2.2 g/kg b.w. in vivo provided that the total amount of active ingredient would be available in the plasma and that the plasma volume is about 6% of the body weight (Kopp, et al.,1981b). In Vivo Rat Groups of 10 male and 10 female rats were intubated with propamocarb hydrochloride as a 70% aqueous formulation at 0 or 3000 mg a.i/kg b.w./day for 11 days. Compound-related mortality occurred in three males and seven females of the treated group on days 7 and 8, and in one treated female on day 9 of treatment. Assay of whole blood cholinesterase on day 7 at 30 minutes, 1 hour, 2 hours and 3 hours after dosing, and of brain cholinesterase on day 11 at 30 minutes post-treatment indicated no significant compound-related inhibition of either tissue. (Hunter, et al., 1978). Dog Groups of one male and two female beagles were given, by gavage, a single dose of a 70% aqueous formulation of propamocarb hydrochloride at 0 or 674 mg a.i./kg b.w. One male and one female of the treated groups died 42 minutes and 35 minutes after treatment, respectively. Mean activity of erythrocyte cholinesterase in the treated group was inhibited (>20%) 22-36 minutes after dosing, as compared to pre-treatment value or to concurrent control level. Complete recovery of the enzyme activity seemed to be evident at 34-56 minutes post treatment. Plasma cholinesterase was not inhibited at either of the two post-dosing sampling periods. Details of the study, such as the assay method for tissue cholinesterase and the exact time of sampling of blood from individual treated animals, were not available. (Kopp, et al., 1981b). EVALUATION FOR ACCEPTABLE DAILY INTAKE BIOCHEMICAL ASPECTS Absorption, Distribution, Excretion and Metabolism Rat After a single oral dose of 0.5 mg/kg b.w. of 14C-propamocarb hydrochloride*, female rats excreted approximately 90% of the administered radioactivity within 24 hours of dosing via the urine (87%), faeces (2.5%) and expired air (<0.3%). Similar rapid elimination of 14C-propamocarb hydrochloride by female rats was also observed following oral administration of 0.5 mg 14C-propamocarb hydrochloride/kg b.w./day for 21 days. During the 21-day dosing period, an average of 83% and 3.2% of the daily administered dose was recovered respectively in the urine and the faeces. At sacrifice, 24 hours after acute or subacute oral dosing, total 14C residues detected in the 19 tissues analyzed including, among others liver, kidney, lung, spleen, heart, adipose tissue, skin and skeletal muscle (but excluding the alimentary tract) accounted for 1.7% of the single dose and approximately 0.3% of the total dose given over a 21 day dosing period (equivalent to approximately 7% of the last daily dose). Female rats with "Acute biliary - and urethra fistula" treated with a single intraduodenal dose of 0.5 mg/kg b.w. of 14C-propamocarb hydrochloride eliminated 81% of the administered radio-activity in the urine as early as six hours after dosing. By 24 hours post- administration, a total of 92% of the 14C was recovered in the urine as compared to only 1.8% in the bile (Kopp et al. 1979). * 14C-propamocarb hydrochloride labelled at the 1-propyl position was used in all of the available rat metabolism studies. In female rats treated with a single oral dose of 10 or 100 mg 14C-propamocarb hydrochloride/kg b.w. ten to 19 urinary metabolites were detected. The major metabolites identified were 2-hydroxypropyl ester propamocarb (15-32% of the radioactivity recovered in the urine) and N - (3 -dimethylaminopropyl) -acetamide (12 - 21%). Small amounts (approx 4%) of 3-hydroxypropyl ester propamocarb were also identifiable but only in rats given 100 mg/kg b.w. The unchanged parent compound accounted for 3-16% of the C14 detected in the urine. The data suggested that the relative amounts of major and minor metabolites found and the presence or absence of certain minor metabolites are related to dosage (Brühl & Celorio, 1982). A further study by the same authors in female rats orally treated with 50 mg 14C-propamocarb hydrochloride/kg b.w./day for ten days indicated the presence of at least 30 urinary metabolites. 2-Hydroxypropyl ester propamocarb (26% of the 14C recovered in the urine),3-3- dimethylaminopropyl)-4-hydroxy-e-methyl-oxazolidin - 2 - one (14%) and propamocarb N-oxide (13%) were the major urinary metabolites identified. Other compounds found in amounts not exceeding 5% each included the parent compound, 3-hydroxypropyl ester propamocarb, mono-demethyl 2-hydroxypropyl ester propamocarb and 3-(N, N-dimethylamino) -propylamine. All of the identified components together accounted for 66% of the radioactivity present in the urine. N - (3-dimethylaminopropyl)-acetamide, identified previously as a urinary metabolite in the rat (Brühl and Celorio 1982), was not found in the present study. (Brühl & Celorio 1984). Fig.1 presents the proposed metabolic pathways for propamocarb in the rat (Brühl & Celorio 1982; Brühl & Celorio 1984). TOXICOLOGICAL STUDIES Special Studies on Reproduction Rat Groups of 25 male and 25 female (Wistar derived, SPF) were fed a 70% aqueous formulation of propamocarb hydrochloride in the diet at 0, 40, 200 or 1000 ppm a.i. for 100 days prior to mating to initiate a three generation (two litters/generation) reproduction study. Weanlings from the second litters were selected to become parents of the next generation. After the second mating trial in each generation, the dams in each dosage group were divided into four subgroups of ten and fifteen (F0 and F1 generations or of approximately equal size (F2 generation). One subgroup was allowed to litter and rear their young until 21 days post partum. The other subgroup was sacrificed on day 19 of gestation for examination of uterine contents. Foetuses were evaluated for external, skeletal and visceral abnormalities. In the parental generations, no compound-related mortalities or overt signs of toxicity were observed. Frequently, a slight decrease (<10%), not dose-related, in food consumption occurred in the treated groups during the premating period of each generation. Parental body weight, pregnancy rate, median pre-coital time, mating performance and duration of gestation period were comparable to control values.Over the three generations, there were no treatment-related effects on litter size on days 1, 4, 12 and 21; pup weight on days 1 and 4; sex ratio of pups and histopathological findings of F3b weanlings. Incidence of dams with total litter loss was increased at 200 ppm only in F1b litters. Pup weight at 1000 ppm was decreased on day 21 in F1a litters and on day 12 in F1b litters. An increase in spleen weight was note in F3b weanlings at 1000 ppm. Examination of pre-weaning pups from each generation for rate of physical development (hair growth, incisor eruption, opening of the auditory canal and the eye) and of selected F1b and F2b animals for pupillary reflex and startle response at about 28 days of age indicated no abnormal findings attributable to the compound. Teratological investigation of F1b, F2b, and F3b litters revealed no significant differences between control and treated groups with respect to number of implantations or corpora lutea, litter size, late resorptions of foetal weight. F2b litters at 1000 ppm exhibited an increase in early resorptions and pre-implantation loss. Increased renal pelvic cavitation, unilaterally or bilaterally, was found in 2/67 foetuses from 2/12 dams at 1000 ppm of the F3b litters, as compared to an incidence of zero in 37 concurrent control foetuses from a total of 9 dams examined for visceral abnormalities. The study demonstrated a dietary level of 200 ppm to be without adverse effect on the reproductive parameters examined. There was no clear evidence for teratogenic potential at any dose tested. (Huntingdon Research Centre, 1983). Special Studies on Teratogenicity (Also see under "Special Studies on Reproduction") Rat Groups of 25 mated female rats (Wistar - Han-Schering, SPF) were intubated with a 70% aqueous formulation of propamocarb hydrochloride in water at 0, 0.1, 0.3, 1.0 or 3.0 ml/kg b.w./days from days 6 through day 19 of pregnancy. The dams were sacrificed on day 20 post-coitum and foetuses were removed for gross external, visceral and skeletal examination. Five dams at 3 ml/kg b.w. and one dam at 1.0 ml/kg b.w. died, but with the exception of 1/5 dams of the top dosage group showing severe pulmonary oedema, no abnormal findings were reportedly seen at autopsy. In the top dosage group, a majority of the dams exhibited toxic signs. Additionally, maternal weight gain between days 16 and 20 post-coitum was depressed and uterine weight was decreased. Also at the same dosage level, adverse effects were observed on the mean number of early resorptions or live foetuses, mean total litter size, incidence of pregnant dams with resorptions of entire litters, post-implantation loss and foetal weight. There were no significant differences between control and treated groups in mean number of corpora lutea or implantations, pre-implantation loss and sex ratio. Foetuses at both 1 and 3 ml/kg b.w. showed an increase (dose-related) in the incidence of retarded ossification. An elevated frequency of foetuses with 14 ribs was seen at 0.3 ml/kg b.w. and above, but a dose-response pattern was not evident. Based on the data, the compound appeared to retard foetal development at and above 1 ml/kg b.w. (approximately equivalent to 700 mg a.i./kg b.w.). A dosage level of 3 ml/kg b.w. (approximately equivalent to 2100 mg a.i./kg b.w.) was toxic to both mothers and foetuses. There was however no clear evidence of teratogenic activity at any level under the conditions of the experiment (Poggel, et al., 1981). Rabbit Groups of 15 to 20 mated female rabbits (New Zealand White) were intubated with a 70% aqueous formulation of propamocarb hydrochloride in water at 0, 0.2, 0.4 or 0.8 ml/kg b.w./day from days 6 through 18 of gestation. The does were sacrificed on day 28 of pregnancy and uterine contents were examined. Live young were evaluated for external malformation and incubated for 24 hours prior to sacrifice for examination for skeletal and visceral abnormalities. Mortality occurred in control and treated groups, but only two deaths at 0.8 ml/kg b.w. appeared to be treatment related. The total number of does showing evidence of pregnancy (including those showing abortions or total resorption) and surviving at termination was 12, 12, 11, 10 respectively at 0, 0.2, 0.4, 0.8 ml/kg b.w. Does at and above 0.4 ml/kg b.w. showed weight loss on gestation day 16 and growth depression on day 28. Pregnancy rate, mean litter size, mean number of early resorptions, incidence of pregnant does with early resorptions, incidence of pregnant does with entire litters resorbed, post- implantation loss and foetal survival rate after six- and 24-hour incubation were all adversely affected in the top dosage group Foetal weight was depressed at both 0.4 and 0.8 ml/kg b.w. Cleft palate, not observed in any of the 71 foetuses from ten concurrent control litters or in any of a combined total of 133 foetuses from 18 litters of the two lower dosage groups, was observed in 1/21 foetuses from five litters examined at 0.8 ml/kg b.w. Historical control data included in the report on the incidence of cleft palate in foetuses of New Zealand White rabbits were of limited value as a basis of comparison due to the absence of the data in question using litter as the sampling unit and lack of information on the time frame over which the data were obtained. There were no significant differences between control and treated groups in the other monitored parameters including the number of implantations or corpora lutea, pre-implantation loss and visceral or skeletal malformations of pups. The study appeared to indicate the teratogenic no-effect level to be at least 0.4 ml/kg b.w. (equivalent approximately to 280 mg/ai/kg b.w.). Maternal and foetal toxicity were evident at this level but not at 0.2 ml/kg b.w. (Huntingdon Research Centre, 1981). Groups of 18 to 21 mated female rabbits (New Zealand White) were treated orally with propamocarb hydrochloride as a 70% aqueous formulation in water at 0, 0.02, 0.06, 0.2, 0.4 or 0.8 ml/kg b.w./day from day 6 to day 18 of gestation. All does were sacrificed on day 28 post coitum and uterine contents were examined. Foetuses were evaluated for external, skeletal and visceral abnormalities. Mortality was not affected by treatment. The number of pregnant does with live foetuses surviving on day 28 was 11, 14, 10, 11, 7, 13 respectively at 0, 0.02, 0.06, 0.2, 0.4, 0.8 ml/kg b.w. Pregnant does at 0.8 ml/kg b.w. showed weight loss on day 18 and a decrease in weight gain on day 28. The mean number of dead foetuses per pregnant doe and the incidence of pregnant does with dead foetuses were increased at 0.4 ml/kg b.w. only. The mean number of early resorptions was elevated and the mean foetal weight was reduced at the top dosage level. Post- implantation loss was increased at both 0.4 and 0.8 ml/kg b.w. Other measured parameters, including number of corpora lutea or implantations, litter size, pre-implantation loss and gross, skeletal and visceral findings of foetuses, were not significantly different from controls. Cleft palate, observed in a single foetus of the top dosage group (0.8 ml/kg b.w.) in a previous rabbit study (Anon., 1981), was not seen in any of the foetuses in the present study. The teratogenic no-effect level was demonstrated at 0.8 ml/kg b.w. (equivalent approximately to 560 mg a.i/kg b.w.) (Schering AG, 1981). Special Studies on Mutagenicity Mutagenicity studies for propamocarb hydrochloride as a 70% aqueous formulation are summarized in Table 1. Food consumption was marginally increased in males at 500 ppm between weeks 79 and 104. Body weight, general appearance and behaviour were unaffected. No gross pathological changes attributable to ingestion of the compound were evident. Histopathological examination of a wide range of tissues from all animals of control and top dosage groups, plus any tissue showing macroscopic abnormality suggestive of neoplasia revealed no treatment-related findings. There was no significant difference between control and treated groups in incidence of any particular type of tumour. The most frequently observed tumours were liver tumours in males, lung tumours in both sexes and lymphoreticular tumours in females. Over 65% of the concurrent controls (both sexes) had spontaneous tumours. Under the condition of the experiment, the test material was not carcinogenic (Hunter, et al., 1983a). Special Studies on Eye and Skin Irritation In primary eye irritation studies with New Zealand White rabbits, a 70% aqueous formulation of propamocarb hydrochloride was found to be slightly irritating to the eye (Schöbel 1977; Ullmann & Suter 1983a). Propamocarb hydrochloride, as a 70% aqueous formulation, was shown to be practically non-irritating to the skin when applied to the intact skin of New Zealand White rabbits (Ullmann & Suter 1983b). In New Zealand White rabbits with skin sites exposed to a 70% aqueous formulation of propamocarb hydrochloride (0.25 ml/site) five hours/day for 28 consecutive days, signs of local irritation including reddening, scabbing and thickening of the pithelium were noted at both intact and abraded sites. Additionally, the abraded sites showed reactions such as swelling and induration. Upon microscopic examination, acanthosis, hyperkeratosis and necrosis were noted in the abraded skin (Schöbel & Schuppler 1976). Special Study on Skin Sensitization A 70% aqueous formulation of propamocarb hydrochloride was not a skin sensitizer in guinea pigs (Schöbel & Schuppler 1977). Special Studies on Pharmacology In mice treated with single intraveneous doses of propamocarb hydrochloride as a 70% aqueous formulation, 30 mg/kg b.w. caused restlessness and increased motor activity. After 100 mg/kg b.w., additional symptoms such as irregular breathing and exophthalmos appeared. Death occurred at 175 mg/kg b.w. and above consequent to the development of clonic convulsions. No clinical signs of toxicity or abnormalities in normal reflexes and autonomic function were seen at 10 mg/kg b.w. or below. (Hara, et al., 1984). Special Studies on Carcinogenicity (See also under "Long Term Studies") Mouse Groups of 60 male and 60 female CD-1 mice, about 35 days old, were fed dietary levels of propamocarb hydrochloride as a 70% aqueous formulation at 0, 20, 100 or 500 ppm a.i. for two years. Mortality was not affected by treatment. At termination, about 17 - 28% males and 42 - 52% females of control and treated groups survived. (Over 53% males and at least 75% females per control and treated group lived at least 78 weeks). Single intravenous doses ranging from 3 to 100 mg/kg b.w. of the 70% aqueous formulation in mice did not produce analgesia or effects on any of the following parameters: convulsions induced by electroshock, barbital-induced anesthesia, pinnal and corneal reflexes and muscular relaxation or coordination. No changes in rectal temperature were detected in rabbits given 10 or 100 mg/kg b.w. of the test formulation intravenously. Transitory alterations in spontaneous EEG patterns were observed in rabbits treated intravenously at 100 mg/kg b.w. but not at 10 mg/kg b.w. and below. (Hara, et al., 1984). Neuromuscular transmission in isolated rat diaphragm was slightly enhanced initially but then slightly inhibited by the formulated product at a concentration of 10-3 g/ml. Neuromuscular contraction in rat gastrocnemius was unaffected in situ after an intravenous dose of 100 mg/kg b.w. The test formulation, at concentrations of 10-5/ml and above, inhibited acetylcholine- or histamine-induced contraction of isolated guinea pig ileum and also acetylcholine-induced contraction of isolated rabbit trachea; and enhanced nor-epinephrine- induced contraction of isolated rat vas deferens. This concentration (10-5 g/ml) did not modify the spontaneous contraction of atria isolated from guinea-pig. The serotonin-induced contraction of isolated rat fundus was depressed only at concentrations of 10-4 g/ml and above. The oxytocin-induced contraction of isolated uterus in oestrous rat was unaffected even at concentrations up to 10-3 g/ml. (Hara, et al., 1984). In anesthetized rabbits, intravenous doses of the formulation at 10 mg/kg b.w. and above produced bradycardia and antihypertensive activity which were not affected by pretreatment with an intravenous dose of 5 mg/kg b.w. of atropine. Tachycardia induced by 0.1 mg/kg b.w. of isoproterenol given intraveneously was not antagonized by intravenous administration of 30 mg/kg b.w. of the propamocarb formulation. Blood coagulation in rats was not significantly affected by an intravenous dose of 100 mg/kg b.w. of the aqueous formulation. In vitro clotting time of blood from the rabbit was prolonged by the formulation at a concentration of 10-2 g/ml but not below (Hara, et al., 1984). Acute Toxicity Acute toxicity of propamocarb hydrochloride to rats, mice, rabbits and dogs is summarized in Table 2. High doses produced hypokinesis, convulsion, staggering gait, ataxia and piloerection within 24 hours post-dosing. Short Term Studies Oral/Dietary Rat Groups of ten male and ten female rats were fed the free base of propamocarb hydrochloride in their diet at 0, 20, 50 or 1000 ppm for 90 days. An additional group of the same size was given 500 ppm for 6 weeks and 1000 ppm for the remaining 7 weeks. There was no mortality or abnormal behaviour. None of the parameters monitored, that is weekly body weight, food consumption, haematology, urinalysis, terminal blood chemistry, activity of plasma, erythrocyte, and brain cholinesterase, were adversely affected. Gross pathological changes and organ weights were not significantly different from those in the controls. Histopathological examination of a number of selected tissues from animals of control and top-dosage groups failed to reveal any treatment-related findings. The no-effect level was demonstrated at 500 ppm (de Rijke Köter & Leegwater, 1976). Groups of 30 male and 30 female rats were fed diets containing propamocarb hydrochloride, in the form of a 70% aqueous formulation, at 0, 200, 1000 or 5000 ppm a.i. for 13 weeks. No mortality or clinical signs were observed. Ophthalmoscopic findings, clinical chemistry and haematology were not influenced by treatment. Activity of plasma and erythrocyte cholinesterase at weeks 7 and 13 or of terminal brain cholinesterase, determined in 24-hour fasted animals, was not inhibited. In females at 5000 ppm, growth was slightly decreased (< 10%) frequently during the study, and water consumption at week 1 was reduced. Feed efficiency was decreased intermittently over the course of the study in males at 5000 ppm and in females at both 1000 and 5000 ppm. Proteinuria occurred in both sexes of all groups including the control at weeks 7 and 13 with the males showing greater degree of severity. At terminal sacrifice a decrease of absolute weight of liver and spleen and an increase in organ/body weight ratio of kidney in both sexes were evident in the high dose only. There were no significant gross pathological changes between control and treated groups. Histopathological evaluation of a number of selected tissues including the bone marrow plus all grossly abnormal tissues from each animal indicated an increase in incidence of granulomatous inflammation of the liver and of hyperplasia of the lymph node in females at 5000 ppm. The study showed the no-effect level to be at least 200 ppm. (Kojima & Enomoto 1982). Dog Groups of pure-bred beagle dogs (four males and four females/ group) were fed the free base of propamocarb hydrochloride in the diet at 0, 50, 100, 500 or 1000 ppm for 90 days with the top dosage level being raised to 2000 ppm at week 7. No compound-related effects were observed on survival, general appearance and behaviour, growth or food consumption, haematology, blood chemistry and urinalysis as well as liver and kidney function tests. Assay of plasma, erythrocyte and brain cholinesterase revealed no significant inhibition. At terminal sacrifice, organ weights and gross pathological changes were not altered by the compound. Microscopic evaluation indicated no compound-related findings. The no-effect level was at least 1000 ppm (Reuzel & Til (1977). Dermal Rabbit Groups of New Zealand White rabbits (three animals sex/group, with skin abraded) were exposed dermally to propamocarb hydrochloride as a 70% aqueous formulation at 0, 0.2, 0.7 or 2.0 ml/kg b.w. under occlusive patch for a period of six-hours/day, five days/week for a total of 15 applications in 21 days. Treated sites were washed at the end of each exposure period. There were no compound-induced systemic effects as judged by mortality, clinical signs, haematology, blood chemistry, organ weight, gross pathology and histopathology. Mild to moderate erythema and oedema were seen in animals of all treated groups and increased with dosage (Field 1980). Table 1. Special Studies on mutagenicity of Propamocarb Hydrochloride Test Test object Concentrations of Purity Results Reference System propamocarb HCL used In Vitro Ames' test S.typhimurium 3.5- 70% negative Hastwell, et al., (with and strains TA 1535, 5,000 ug/plate aq with or without 1977; without TA100,TA1537 solv. metabolic Kojima & metabolic TA1538,TA98 activation Nakajima 1981a activation) E.Coli WP2uvrA Rec-assay Bacillus+subtilis 500- 70% negative Kojima & H17 (rec±) and 10,000 ug/disk aq without Nakajima 1981b M45 (rec) solv. metabolic activation Saccharomyces cerevisae Mitotic strain D4 ) 1,000- 70% negative Jagannath & Brusick, gene mutation ) 10,000 ug/plate aq. with or without Hoorn, 1980 ) solv. metabolic Reverse strains S138 and ) activation mutation S211C ) ) Mitotic strain D5 ) recombination ) In Vivo Micronucleus Mouse 1,250 to 5,000 70% negative Richold & Richardson, test mg/kg b.w. aq. Hossack,1980 orally solv. Table 1. (continued) Test Test object Concentrations of Purity Results Reference System propamocarb HCL used Dominant Mouse 424 to 1,237 70% negative Jorgenson & Jones, lethal assay mg/kg b.w./day aq. Rushbrook,1979 for 8 weeks in solv. drinking water; prior to mating weekly for 2 consecutive weeks Table 2. Acute Toxicity of Propamocarb Hydrochloride to Animals LD50 Species Sex Route (mg a.i/kg b.w.) Reference Mouse M + F oral 1600 to >2858 Schöbel & Etreby, 1976a & 1976b; Rushbrook, et al., 1982a,Kojima, et al., 1982a M s.c. 1710 Kojima, et al., F 1870 1982b M i.p. 457 Kojima, et al., F 435 1982c M + F dermal >3000 Kojima, et al., 1982d Rat M + F oral 2000 to Kojima, et al., 1982e 8600 Schöbel & Siegmund, 1976a M s.c. 5220 Kojima,et al.,1982f F 3230 Rat M + F i.p. 437-763 Schöbel & Schuppler, 1977; Kojima, et al., 1982g Rat M + F dermal >3920 Schöbel & Siegmund, (duration of 1976g exposure not specified) Rat M + F dermal >3000 Kojima, et al., 1982h (24-hour exposure) Rat M + F inhalation >3960 mg/m3* Robkamp & (4-hour Schuppler, 1976 "nose only" exposure Table 2. (continued) LD50 Species Sex Route (mg a.i/kg b.w.) Reference Rabbit M + F dermal >3920 Schöbel & Siegmund (duration of 1976c exposure not specified) Dog** M + F oral <674 Kopp, et al., 1981a & 1981b * 4-hour LC50 ** 674, 1000 and 2000 mg/kg produced 3/6 mortalities with emesis of doses > 1000 mg/kg. Long-term Studies Rat Groups of 50 male and 50 female Sprague-Dawley CD rats were fed diets containing propamocarb hydrochloride as a 70% aqueous formulation at 0, 40, 200 or 1000 ppm a.i. for 104 weeks. Additional animals (ten males and ten females per group) were fed the same dietary levels for the same duration and used primarily for routine laboratory investigations (satellite group). Two additional groups of ten males and ten females were fed 0 or 1000 ppm of the test diet with one-half of the animals in each group sacrificed after 52 weeks and the remainder at the end of a four-week withdrawal period. These animals were subjected to macroscopic examination and organ weight analysis. Mortality was not influenced by treatment. Forty-six to 58% of the males and 30-44% of the females of all groups including the control survived at the end of two years. Over 50% of the animals (both sexes) of control and treated groups lived at least 91 weeks. Compound-related clinical signs were not apparent. No consistent dose- related changes were seen on body weight, food consumption and water intake. Haematological, clinical chemistry and urinalysis values as well as ophthalmoscopic findings, monitored at several intervals over the course of the study, were not significantly different between control and treated groups. Activity of tissue cholinesterase was not measured at any time during the study. Gross pathological changes in treated animals dying or sacrificed in extremis during the study and in those sacrificed at 52 weeks, after the four-week withdrawal period, or terminally were comparable to those in the control group. Organ weight determinations revealed no significant difference between control and treated groups. Histopathological evaluation of non- neoplastic findings was unremarkable except for an increased incidence of degenerative hepatocytes/necrosis in high-dose males. Evaluation of the neoplastic changes demonstrated an increase in occurrence in males of subcutaneous fibrosarcoma in the treated groups. Incidence of the tumour was 0/58 in controls, 5/56 (8.9%) at 40 ppm, 2/58 (3.5%) at 200 ppm and 7/55 (12.7%) at 1000 ppm (the denominator denoted the number of survivors from both main and satellite groups at each dosage level at the end of 51 weeks when the first subcutaneous fibrosarcoma was detected in the males). The difference from concurrent controls was statistically significant at 40 ppm and 1000 ppm. Data on background incidence of subcutaneous fibrosarcoma in the particular strain of rats employed in the study were not available in the report. Over 80% of the concurrent controls (both sexes) had tumours, with pituitary adenoma (both sexes), mammary tumours (females) and subcutaneous fibroma and lipoma (males), the most prevalent tumours. There were no other neoplastic differences between treated and control groups. The no-effect level for non-neoplastic effects was equal to 8.3 mg a.i/kg b.w./day, based on food consumption and body weight data (Hunter, et al., 1983b). Comments Propamocarb hydrochloride was evaluated for the first time by the JMPR at this session. The compound, a carbamate fungicide, is rapidly absorbed, degraded and readily excreted primarily in the urine of (female) rats. Oxidation of the parent molecule appears to be the major metabolic pathway. There is no evidence of significant tissue accumulation of propamocarb hydrochloride and/or its metabolites. Metabolism data in mammalian species other than the rat are not available. Propamocarb hydrochloride has a relatively low order of acute oral toxicity in rodents, with LD5 values of over 1500 mg/kg b.w. in both mice and rats. Limited acute oral data in dogs appeared to indicate that they are more sensitive than rodents to toxicity of the compound. A three-generation reproduction study, including teratological investigation in rats, showed a no-effect level of 200 ppm on reproduction and teratogenicity. A teratology study in rats showed retardation of foetal development at doses which were maternally toxic. Teratology studies in rabbits were negative. Mutagenicity studies were also negative. A carcinogenicity study in mice was negative. A long-term study in rats showed some evidence of increased incidence of sub-cutaneous fibrosarcoma. Therefore, background data on incidence of this malignancy in the particular strain of rats are required. Ninety-day feeding studies in rats and dogs established no-effect levels of at least 200 ppm and 1000 ppm respectively. Inhibition of brain and erythrocyte cholinesterases was not observed in these studies. In view of the concerns with respect to the elevated incidence of subcutaneous fibrosarcoma in male rats of the long-term study and the non-availability of a dog study longer than three months, only a temporary ADI was granted. Level causing no toxicological effect Rat: 200 ppm in the diet, equivalent to 8.3 mg/kg b.w. Dog: 1,000 ppm in the diet, equivalent to 25 mg/kg b.w. Estimate of temporary acceptable daily intake for humans 0 - 0.2 mg/kg b.w. Further work or information Required (by 1986): Historical data on the incidence of subcutaneous fibrosarcoma in the CD strain of rats used in the long-term study. Complete data on the 24-month dog study known to have been completed. Metabolism and pharmacokinetic studies in mice and rats using multiple dosage levels. Desirable: Observations in humans. Complete data on the 4-5 week feeding study in rats. REFERENCES Brühl, R. & Celorio, J. Propamocarb hydrochloride: Metabolism in rats. 1982 Submitted by Schering AG to WHO. (Unpublished). 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Hoorn, A.J.W., Jagannath, D.R. & Brusick, D.J. Mutagenic evaluation of 1980 Previcur N. Batch No. 271001B00000 in the mitotic gene conversion, reverse mutation & mitotic recombination assays in yeast. Litton Bionetics, Inc. Submitted by Schering AG to WHO. (Unpublished). Hossack, D.J.N., Richold, M. & Richardson, J.C. Micronucleus test on 1980 CP604 (SN66752, Previcur N). Huntingdon Research Centre, England. Submitted by Schering AG to WHO. (Unpublished). Hunter, B., Jones, D.R., Heywood, R., Street, A.E. & Gibson, W.A. 1978 Previcur N (SN66752). Assessment of whole blood & brain cholinesterase activities in rats after 11 days of treatment by oral gavage. Huntington Research Centre, England. Submitted by Schering AG to WHO. (Unpublished). Hunter, B., Watson, M., Read, R.M., Prentice, D.E., Woodhouse, R.N., 1983a Cherry, C.P. & Gibson, W.A. Previcur N (SN 66752): Potential tumorigenicity to mice in dietary administration for 104 weeks (final report). Huntingdon Research Centre, England. Submitted by Schering AG to WHO. (Unpublished). Hunter, B., Jones, D.R., Heywood, R., Street, A.E., Jolly, D.W., 1983b Offer, J.M. & Gibson, W.A. Previcur N (SN66752): Toxicity & potential tumorigenicity in dietary administration to rats for 104 weeks. (final amended report). Huntingdon Research Centre, England. Submitted by Schering AG to WHO. (Unpublished). Huntingdon Research Centre. Previcur N teratology study: effect of 1981 administration during organogensis on foetuses of the rabbit. Reprotox, Deutschland. Submitted by Schering AG to WHO. (Unpublished). Huntingdon Research Centre. Effect of Previcur N on reproductive 1983 function of multiple generations in the rat. Reprotox, Deutschland. Submitted by Schering AG to WHO. (Unpublished). Kojima, K. & Nakajima, M. Mutagenicity test in bacteria with Previcur 1981a N. Biosafety Research Centre, Foods, Drugs & Pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kojima, K. & Nakajima, M. "REC" assay to detect mutagenic activity of 1981b Previcur N. Biosafety Research Centre, Foods, Drugs & Pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kojima, K. & Enomoto, M. Previcur N: Three-month subchronic oral 1982 toxicity study in rats. Biosafety Research Centre, Foods, Drugs & Pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kojama, K. Seki, S. & Okamura, T. Previcur N: Acute oral toxicity in 1982a mice. Biosafety Research Center, Foods, Drugs & Pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kojima, K. Seki, S. & Okamura, T. Acute subcutaneous toxicity study in 1982b mice. Biosafety Research Center, Foods, Drugs & Pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kojima, K., Seki, S. & Okamura, T. Previcur N: Acute intraperitoneal 1982c toxicity study in mice. Biosafety Research Center, Foods, Drugs & Pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kojima, K., Seki, S. & Okamura, T. Previcur N: Acute percutaneous 1982d toxicity study in mice. Biosafety Research Center, Foods, Drugs & Pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kojima, K., Seki, S. & Okamura, T. Acute oral toxicity study in rats. 1982e Biosafety Research Center, Foods, Drugs, & Pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kojima, K., Seki, S. & Okamura, T. Acute subcutaneous toxicity study 1982f in rats. Biosafety Research Center, Foods, Drugs & Pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kojima, K., Seki, S. & Okamura, T. Acute intraperitonial toxicity 1982g study in rats. Biosafety Research Center, Foods, Drugs and pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kojima, K., Seki, S. and Okamura, T. Acute percutaneous toxicity study 1982h in rats. Unpublished report from Biosafety Research Center, Foods, Drugs and Pesticides, Japan. Submitted by Schering AG to WHO. (Unpublished). Kopp, R., Hümpel, M., Kühne, G. Aner, B., Klawa, D. & Rzadkiewicz, M., 1979 Pharmacokinetics of Propamocarb hydrochloride on single & repeated oral administration of 0.5 mg/kg in rats. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Kopp, R., Günzel, P., RoBkamp, G., Schöbel, C. & Siegmund, F. Previcur 1981a N. Systemic tolerance test (LD50) ZK66752(CP604) in the dog following single oral administration. Schering AG. Submitted by Schering AG to WHO. (Unpublished) Kopp, R., Günzel, P., Bhargava, A.S., Schöbel, C. & Slabke, P. 1981b Influence of SN66.752 upon the acetylcholinesterase activity in vitro (dog & rat) and in vivo (dog) after single oral administration. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Poggel, H.A., Kopp, R. & Günzel, P. Previcur N. (CP604). 1981 Embryotoxicity including teratogenicity study in rats after daily intragastrical administration from day 6 to day 19 of gestation. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Reuzel, P.G.J. & Til, H.P. Subchronic (90-day) feeding study with 1977 ZK17.296 (SN39744 Propamocarb) in dogs (final report). Centraal Instituut Voor Voedingsonderzoek, The Netherlands. Submitted by Schering AG to WHO. (Unpublished). RoBkamp, G. & Schuppler, J. ZK66752 Acute Inhalation toxicity to the 1976 rats (M + F) of aqueous ZK66.752 following single four-hour continuous exposure (LC50). Schering AG. Submitted by Schering AG to WHO. (Unpublished). Rushbrook, C.J., Jorgenson, T.A. & Jones, D.C.L. Dominant lethal study 1979 of Previcur N. SRI International, USA. Submitted by Schering AG to WHO. (Unpublished). Schering A.G. Previcur N (CP604): embryotoxicity including 1981 teratogenicity study in rabbits after daily intragastrical administration from day 6 to day 18 of gestation. Submitted by Schering AG to WHO. (Unpublished). Schöbel, C. SN66752. Eye irritation, rabbits: single application of 1977 CP604 to the rabbit eye. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Schöbel, C. & Etreby, M.F. El. ZK66752: Acute oral (i.g.) toxicity 1976a mice (male) single administration. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Schöbel, C. & Etreby, M.F. El. ZK66752. Acute oral (i.g.) toxicity 1976b mice (female) single administration. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Schöbel, C.J. and Schuppler, J. SN6675: Dermal toxicity study of CP604 1976 on the intact and scarified skin of the rabbit following daily application for 28 days. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Schöbel, C. & Schuppler, J. ZK66752. Acute i.p. toxicity rats (M + F) 1977 single application. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Schöbel, C. & Siegmund, F. ZK66752: acute oral (i.g.) toxicity rats 1976a (M + F) single administration. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Schöbel, C. & Siegmund, F. ZK 66752: acute dermal toxicity rats 1976b (M + F) single administration. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Schöbel, C. & Siegmund, F. ZK66752. Acute dermal toxicity rabbits 1976c (M + F) single administration. Schering AG. Submitted by Schering AG to WHO. (Unpublished). Ullmann, L. & Suter, B. Primary eye irritation after single 1983a application with Previcur N in the rabbit. Research & Consulting Co., AG, Switzerland. Submitted by Schering AG to WHO. (Unpublished). Ullmann, L. & Suter, B. Primary skin irritation following a single 1983b four-hour occlusive application with Previcur N in the rabbit. Research & Consulting Co., AG., Switzerland. Submitted by Schering AG to WHO. (Unpublished).
See Also: Toxicological Abbreviations Propamocarb (Pesticide residues in food: 1984 evaluations) Propamocarb (Pesticide residues in food: 1986 evaluations Part II Toxicology) Propamocarb (JMPR Evaluations 2005 Part II Toxicological)