Induction of cytochrome P-450IA1 in fetal rat liver by a single dose of 3-methylcholanthrene

Pregnant Sprague-Dawley rats were treated with a single ip dose of either olive oil or 40 mg/kg of 3-methylcholanthrene on gestation day 20 and sacrificed at various times after injection. Determination of aryl hydrocarbon hydroxylase activity 24 hr after injection revealed that treatment with 3-methylcholanthrene resulted in a 10.5-fold stimulation of enzymatic activity in liver 800 x g supernatants. Western blot analysis with monoclonal antibody 1-7-1 confirmed these results and demonstrated the presence of a 3-methylcholanthrene-inducible P-450 isozyme. Using Northern and slot blot techniques, the induction of steady-state levels of CYPIA1 RNA was shown to occur as early as 4 hr following 3-methylcholanthrene injection. CYPIA1 RNA levels were induced 31.6-fold over values obtained from oil-treated tissues at this time. This appears to be the optimal time to study changes in the levels of CYPIA1 RNA gene expression in the fetus following transplacental exposure to polycyclic aromatic hydrocarbons. By 12 to 24 hr postinjection, the induction of CYPIA1 RNA levels declined to 3.5- to 8.5-fold above control values. These results demonstrate that the kinetics of induction of the CYPIA1 gene during the fetal period differed from that seen in adults.

Coca paste: chemical analysis and smoking experiments

Several samples of Colombian and a sample of Peruvian coca paste were subjected to chemical analysis to ascertain the complexity of these products. A neutral and acid fraction and a basic fraction were analyzed by gas chromatography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS). The basic fraction was also analyzed as its trimethylsilyl (TMS) derivative. Several gasoline residue components were identified in the neutral fraction. In addition to cocaine (greater than 60% in all cases), other alkaloids were identified. Lead and manganese analyses were carried out on these samples. While all the samples contained no lead (less than 45 ppm), most of the Colombian samples contained significant amounts of manganese (greater than 5%). Preliminary smoking experiments with a Colombian coca paste sample indicated that it behaves more like free cocaine than like a cocaine sulfate salt.

Role of the maternal environment in determining susceptibility to transplacentally induced chemical carcinogenesis in mouse fetuses

Treatment of pregnant mice with 3-methylcholanthrene (MC) causes lung and liver tumors in the offspring, the incidences of which are greatly influenced by the Ah locus regulated induction phenotype for aryl hydrocarbon hydroxylase activity (AHH) in both the mother and fetuses. In order to examine the biochemical and molecular mechanisms responsible for the modulating effect of maternal environment on tumor susceptibility, reciprocal crosses between responsive C57BL/6 and non-responsive DBA/2 mice were made and the pregnant mothers were treated i.p. on the 17th day of gestation with either olive oil alone, 30 mg/kg of MC, or 30 mg/kg of beta-naphthoflavone (beta NF). At various times after injection, the mothers were killed and the fetuses removed for enzymatic and molecular blot analysis. In fetal lung tissues, the absolute levels and relative induction ratios of AHH activity from D2B6F1 fetuses were very similar to those obtained in B6D2F1 fetuses during the first 24 h following a transplacental exposure to either inducing agent. This was also the case 48 h after an injection of beta NF. However, 48 h after exposure to MC, the AHH activity in fetal lungs from B6 mothers had declined to practically control values, whereas fetal lungs from D2 mothers still exhibited a high level of AHH activity. Similar induction kinetics for the CYPIA1 gene were obtained in fetal livers. These results were confirmed at the RNA level by quantitative slot-blot analysis of fetal RNA preparations. In both organs, treatment with inducing agents for the P450IA1 gene resulted in a rapid and early induction of CYPIA1 RNA by 4 h. Fetuses from D2 mothers, however, showed a more sustained induction of CYPIA1 RNA following exposure to MC than did fetuses from B6 mothers. These results suggest that the observed increase in tumor susceptibility observed in the offspring of D2 mothers compared to the offspring of B6 mothers was due, at least in part, to the differences in the persistence of induction of the CYPIA1 gene locus, and may be the result of differences in the clearance rates of MC from the fetal and maternal compartments or its pharmacokinetic distribution in the two types of maternal environments.

Cross-reactivity of selected compounds in the Abbott TDx cannabinoid assay

Immunoassay procedures, both enzyme immunoassay and radioimmunoassay, continue to be widely used to screen samples for recent marijuana use by analyzing the urine samples for 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (11-nor-delta 9-THC-9-COOH) (the major urinary metabolite of delta 9-tetrahydrocannabinol [delta 9-THC]). Using commercially available immunoassay reagents, the cross-reactivity of the antiserum utilized in Abbott's TDx cannabinoid assay (a fluorescence polarization immunoassay) was evaluated. This cross-reactivity was evaluated against a group of cannabinoids and noncannabinoid phenolic constituents of Cannabis, some cannabinoid metabolites, and other agents that appear in normal urine samples. In general, the antiserum was equally reactive toward 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid, its glucuronide, and the corresponding delta 8-isomer, which was the acid moiety utilized in standards and controls of the assay prior to January, 1990. Reduced binding to the antiserum was observed with hydroxylated derivatives of delta 9- and delta 8-THC, and the other cannabinoids, in general, exhibited limited binding potentials toward the antibody. For the noncannabinoid constituents, no binding was observed at the highest concentrations evaluated (40 mg/L).

Effect of pretreatment with beta-naphthoflavone on tumorigenesis by N-nitrosoethylurea in five mouse strains

The non-carcinogenic inducer of the Ah locus, beta-naphthoflavone (beta NF), was administered to females of 5 mouse strains at a dose of 150 mg/kg 48 h before treatment with a tumorigenic dose of the direct-acting carcinogen, N-nitrosoethylurea (ENU), once weekly for 4 weeks. The strains used were C57BL/6, C3H/He and NIH Swiss (responsive to Ah locus induction) and AKR and DBA/2 (induction-non-responsive). The ENU caused primary lung tumors in all strains and in some cases smaller numbers of other neoplasms, including lymphomas, sarcomas and hepatocellular tumors. The beta NF pretreatment did not reduce the numbers of any of the tumors, compared with mice given ENU alone. This result is in contrast to previous findings of a strong protective effect of beta NF against tumorigenesis in Ah-responsive strains by the metabolism-dependent carcinogens, benzo[a]pyrene and 3-methylcholanthrene and confirms that this protection is directly related to enzyme induction. beta NF treatment caused a significant doubling in the number of lung tumor bearers among the ENU-exposed C57BL/6 mice but in no other strain, suggesting the possibility of strain-specific tumor promotion.

The formation of 3-methylcholanthrene-initiated lung tumors correlates with induction of cytochrome P450IA1 by the carcinogen in fetal but not adult mice

The administration of 3-methylcholanthrene (MC) to pregnant mice results in the formation of lung tumors in the offspring. Previous work has shown that fetuses demonstrating inducibility of aryl hydrocarbon metabolism develop two to five times more lung tumors than induction-nonresponsive littermates. In this study, the effects of fetal versus adult MC exposure were compared with regard to both induction of aryl hydrocarbon hydroxylase activity (AHH) in lung and dependence of lung tumorigenesis on the Ah genotype. In inducible (C57BL/6 X DBA/2)F1 fetal lung supernatants, a single ip injection of 100 mg/kg of MC to the mothers resulted in a maximal 50-fold induction of AHH activity by 8 hr, which persisted for 48 hr. The enzyme data agreed well with RNA blot analysis, as MC caused maximal induction of P450IA1 RNA by 4 hr. For comparison, adult (F1 X DBA/2) mice were given three weekly injections of 100 mg/kg MC and tumor incidences were determined after 16 weeks. No differences were observed between responsive and nonresponsive mice of either sex in the number of mice bearing lung tumors, nor did the tumor multiplicity differ between responsive and nonresponsive males. However, noninducible female mice had a significantly higher tumor multiplicity than their inducible counterparts (p less than 0.025). Single ip injections of MC to adult F1 mice revealed that lung AHH activity was increased only 4- to 7-fold in the adult animal compared to the large fetal induction ratio. The difference in the magnitude of induction was due to the higher constitutive levels of AHH activity seen in adult tissue (4- to 14-fold greater than maximal basal fetal levels), as fetal and adult supernatants showed similar levels of induced activity following MC treatment. These results suggest that the correlation between susceptibility to MC-initiated lung tumors and induction of cytochrome P450IA1 is a unique property of the fetus and may be due, in part, to the low basal levels of fetal activating enzymes and their high induction ratio during the fetal period.

Renal function during onset of carbachol-induced hypertension in conscious rats

This study evaluated the changes in renal function that occur during the early phases of chronic infusion of carbachol into the lateral ventricle in conscious rats. Infusion of 1.0 micrograms/h of carbachol i.c.v. resulted in a prompt pressor response with mean arterial pressure rising 20 mm Hg within 15 min. The pressure remained elevated for the duration of a 2-hour infusion. Carbachol infusion at 0.5 micrograms/h induced a similar elevation in blood pressure, but the onset was delayed, reaching significance only after 30-60 min. The higher dose of carbachol was associated with a marked and sustained natriuresis, with sodium excretion increasing from 2.1 +/- 0.3 to 5.3 +/- 1.0 microEq/100 g min after 2 h, compared to 2.0 +/- 0.5 and 1.8 +/- 0.3 microEq/100 g min in vehicle-infused control animals. Sodium excretion did not change significantly in animals infused with carbachol at 0.5 microgram/h. There were no significant changes in glomerular filtration rate in any of the groups. Plasma levels of atrial natriuretic peptide (ANP) were not altered significantly by ventricular infusion of carbachol (188 +/- 99 before vs. 83 +/- 17 pg/ml after infusion). It is concluded that the pressor response to central carbachol infusion is not dependent on retention of sodium and water. The natriuresis observed with carbachol infusion can be dissociated from the pressor response, and is not mediated by ANP.

Morphine and Codeine in Biological Fluids: Approaches to Source Differentiation

Heroin, morphine, and codeine are among the most abused opiate analgesics today. Analysis of individuals' urines for morphine and codeine is sued as an indication of prior ingestion of these dugs. Poppy seeds and products containing poppy seeds are found to have small amounts of morphine and codeine (usually less than 200 µg morphine/g seeds and much less codeine), which is enough to produce a positive urine test for opiates. This manuscript reviews current data on the analysis of various poppy seed products and urine specimens from individuals ingesting these products. A brief review of the metabolism and elimination of these drugs is presented, with general guidelines for differentiation of poppy seed use versus condone, morphine, or heroin abuse.

Differential induction of fetal mouse liver and lung cytochromes P-450 by beta-naphthoflavone and 3-methylcholanthrene

Previous studies have shown that the incidences of liver and lung tumors in mice exposed transplacentally to 3-methyl-cholanthrene (MC) were significantly influenced by the sensitivity of both mothers and fetuses to induction of cytochrome(s) P-450 by polycyclic aromatic hydrocarbons. In order to delineate further the biochemical and molecular processes underlying the observed biological effects, the inductive effect of MC and beta-naphthoflavone (beta NF) on cytochrome P-450 was determined at the biochemical and molecular levels. C57BL/6 females were mated with DBA/2 males and treated i.p. on day 17 of gestation with olive oil alone, 150 mg/kg of beta NF or different doses of MC. At various times after injection the mothers were sacrificed and the fetuses removed for biochemical and molecular studies. MC caused maximal induction of aryl hydrocarbon hydroxylase (AHH) activity by 8 h in both the liver and lung. beta NF caused nearly maximal induction of AHH activity by 8 h in the lung but had little effect on liver AHH activity at this time. Maximal induction with beta NF occurred by 24 h in both organs. Addition of monoclonal antibody 1-7-1, specific for the MC-inducible forms of cytochrome P-450 (P-450IA1 and A2), to the incubation mixtures resulted in a 55-70% inhibition of AHH activity in both lung and liver assays, regardless of the inducing agent used, while having no effect on AHH activity from oil-treated mice. RNA blot analysis carried out in parallel with enzyme assays demonstrated that the levels of enzyme activity correlated very well with the levels of steady-state RNAs. MC caused maximal induction of P-450IA1 RNA levels 4 h after injection in both organs and a biphasic secondary increase was observed in the lung. Maximal levels of P-450IA1 RNA were seen at 12-16 h following injection of beta NF. However, the ratio of P-450IA1 RNAs present at 16 versus 2 h in the beta NF-treated liver appeared greater than that in the lung. P-450IA2 was also induced in fetal liver and lung, but at low levels relative to P-450IA1. The results indicate that the increase in functional AHH activity was primarily due to induction of cytochrome P-450IA1. The differences in induction kinetics observed for cytochromes P-450IA1 and A2 suggest that these enzymes exhibit both tissue- and inducer-dependent specificity.

Modification of transplacental tumorigenesis by 3-methylcholanthrene in mice by genotype at the Ah locus and pretreatment with beta-naphthoflavone

Transplacental lung and liver tumorigenesis in the mouse by 3-methylcholanthrene (MC) was assessed as a function of inducibility of MC metabolism in fetus and in mother, and of pretreatment of the mothers with a noncarcinogenic inducer, beta-naphthoflavone (beta NF). Pregnant (C57BL/6 X DBA/2)F1 females (genotype Ahb Ahd, inducer responsive) mated to DBA/2 males received 45 or 100 mg/kg MC on gestation day 17, and DBA/2 females (genotype Ahd Ahd, nonresponsive) mated to F1 males were given 5 or 30 mg MC/kg. These crosses generated both responsive and nonresponsive offspring. Phenotype and tumor incidences were determined at 13 months of age. The transplacental action of MC was dose dependent and resulted in more lung and liver tumors in induction-responsive offspring than in nonresponsive littermates in most comparisons. beta NF alone did not result in increased numbers of tumors. Significant, complex effects were seen when the mothers were pretreated with beta NF (150 mg/kg) on gestation day 15, before MC on day 17. The beta NF pretreatment protected the fetuses of the F1 mothers: there was a significant overall 30 to 50% reduction in numbers of lung and liver tumors. The greatest effect was seen in the induction-responsive males, who experienced a 50% reduction in both incidence and multiplicity of lung tumors after 100 mg MC/kg, compared with males exposed to MC only. By contrast, beta NF pretreatment of DBA mothers had no general effect but rather potentiated the action of the 5 mg MC/kg dose on multiplicity of lung tumors in inducible males, causing a significant 4-fold increase. It also caused a 60% increase in inducible male liver tumor multiplicity when given before the 30 mg MC/kg dose. Thus, beta NF pretreatment was protective when the mother was inducible, especially in the inducible fetuses of such a mother, but when the mother was noninducible the beta NF pretreatment had no effect in some situations and potentiated the action of the carcinogen in others, mainly in inducible fetuses. These results underscore the fact that induced maternal and fetal metabolism contribute to risk of transplacental tumorigenesis by MC in qualitatively opposite ways.

Gas chromatographic/mass spectrometric analysis of morphine and codeine in human urine of poppy seed eaters

In this study, poppy seeds were examined for a natural constituent that might serve as a maker for the seeds' ingestion as opposed to opiate abuse. Thebaine was selected as possible marker, since it was found to be a component of all poppy seeds examined and was not a natural component of different heroin samples. During the course of this investigation, a new extraction and cleanup procedure was developed for the gas chromatographic/nitrogen phosphorus detection (GC/NPD) and gas chromatographic/mass spectrometric (GC/MS) analysis of morphine and codeine in urine. A linear response, over a concentration range of 25 to 600 ng/mL, was obtained for codeine and morphine (r = 0.9982 and 0.9947, respectively). The minimum detectable level (LOD) and limit of quantitation (LOQ) for morphine were 10 and 30 ng/mL, respectively; whereas LOD and LOQ for codeine were 2 and 8 ng/mL, respectively. The coefficients of variance (CV, n = 6) for morphine and codeine analyses at the 100-ng/mL level were 13.3 and 4.6%, respectively. This procedure was used for the analysis of urine samples from five poppy seed eaters who each ingested 200 g of poppy seed cake. Results indicated that significant amounts of morphine and codeine are excreted in urine and that in all subjects, at least at one point in time, the apparent morphine concentration as determined by radioimmunoassay (RIA) analysis exceeded the cutoff value (300 ng/mL) established for screening. Thebaine was not detected in urine specimens collected following poppy seeds ingestion and thus could not be used as a marker.

Immunohistochemical determination of inducibility phenotype with a monoclonal antibody to a methylcholanthrene-inducible isozyme of cytochrome P-450

A monoclonal antibody (MAb) to a methylcholanthrene (MC)-induced cytochrome P-450, designated MAb 1-7-1, was used for immunohistochemical staining of formalin-fixed tissues from oil- and MC-treated C57BL/6, DBA/2, and [(C57BL/6 X DBA/2) F1 X DBA/2] F2 mice. An avidin-biotin-peroxidase complex immunohistochemical technique was used. For controls, the tissues were also exposed to MAbs 1-48-5 and HyHel-9 (to egg white lysozyme). In liver, MAb 1-7-1 specifically stained the cytoplasm of centrilobular hepatocytes of C57BL/6 mice treated with MC (80 mg/kg) 48 h before kill; staining was not observed with vehicle-treated C57BL/6 mice, with oil- or MC-treated DBA/2 mice, or with comparable antibody concentrations of control MAbs 1-48-5 or HyHel-9. In the F2 mice, about 50% were expected to be MC inducible (AhbAhd). Inducibility phenotype was determined by measuring the conversion of [14C]MC to oxidized and conjugated products by liver homogenates. In freshly fixed material from MC-treated mice, those livers shown by the determination of phenotype to be inducible also stained with MAb 1-7-1, whereas those not induced were immunohistochemically negative. Furthermore, there was a significant positive correlation between degree of staining and the level of MC-metabolizing activity measured biochemically. The immunohistochemical procedure was also accurate in determination of inducibility phenotype of livers that had been in paraffin blocks for up to 2 yr if more concentrated antibody was used. In lung, MAb 1-7-1 stained specifically the alveolar walls and endothelium of blood vessels in MC-induced C57BL/6 mice only; the control MAbs and other mice gave negative results. Similarly, in kidney MAb 1-7-1 stained only glomeruli and interstitial tissue of MC-induced C57BL/6 mice and only endothelium of blood vessels in the colons of these mice. These observations are consistent with induction of the cytochrome P-450 recognized by MAb 1-7-1 in the endothelial cells of extrahepatic tissue. Immunohistochemical staining with MAb thus shows great promise for highly specific localization of particular species of cytochromes P-450 in tissues, for in situ quantification of these enzymes, and for determination of inducibility phenotype with fixed material.

Spectrophotometric evaluation of carboxyhemoglobin in blood of mice after exposure to marijuana or tobacco smoke in a modified Walton horizontal smoke exposure machine

Carboxyhemoglobin (COHb) values were determined in mice exposed to varying amounts of marijuana and tobacco cigarette smoke utilizing a spectrophotometric technique. Mice were exposed to smoke inhalation in a modified Walton horizontal smoke exposure machine, whereby rodents can be exposed to multiples of 1-min smoke exposure cycles. Smoke exposure was intermittent; during the first 30 sec of each 1-min cycle, the subjects were exposed to smoke diluted either 1:10 or 1:5 with air. During the second half of the cycle the animals were given fresh air. There was a positive linear relationship between COHb values obtained and the number of puffs of marijuana smoke administered via either 2, 4, 6, or 8 "puffs" of marijuana smoke. COHb levels in plasma did not increase in animals given multiple 8-puff episodes of smoke daily as long as a 60-min period was interposed between smoking episodes. COHb values in mice exposed to tobacco smoke were significantly higher than those in mice receiving equal numbers of exposures to marijuana smoke. Mean COHb values of mice receiving 8 consecutive puffs of marijuana smoke were 18.6 and 22.0% saturation, but CO was rapidly cleared from the blood. This rapid clearance suggests that the binding affinity of CO for mouse hemoglobin may be be weaker than that of human hemoglobin. Mice similarly exposed to 6 or 8 puffs of tobacco smoke had mean COHb values of 24.6 and 28.5% saturation, respectively. No acute lethal effects were observed in mice receiving multiple daily episodes of 8 puffs per episode of marijuana smoke, whereas mice exposed to a single 8-puff episode of tobacco smoke suffered about 50% acute lethal effects.

Comparison of serum progesterone levels in dogs after administration of progesterone by vaginal tablet and vaginal suppositories

Serum progesterone levels from a vaginal tablet formulation and six different vaginal suppository formulations, each containing 25 mg of progesterone, were evaluated in mongrel dogs. Bioavailabilities relative to an intravenous dose of progesterone were calculated. The vaginal tablet was found to have a significantly higher bioavailability compared with the vaginal suppositories.

Fetal mouse susceptibility to transplacental lung and liver carcinogenesis by 3-methylcholanthrene: positive correlation with responsiveness to inducers of aromatic hydrocarbon metabolism

The role of metabolic activation of carcinogens in fetal tissue as a determinant of sensitivity in transplacental carcinogenesis was investigated in a pharmacogenetic experiment utilizing backcrosses of C57BL/6 (AhbAhb, responsive to induction of aromatic hydrocarbon metabolism) and DBA/2 (AhdAhd, non-responsive) mice. Responsive (C57BL/6 X DBA/2)F1 and non-responsive DBA mothers, all carrying both responsive (AhbAhd) and non-responsive (AhdAhd) fetuses, were given i.p. doses of the carcinogen 3-methylcholanthrene (MC) ranging from 5 to 175 mg/kg on gestation day 17. At 10 months of age the metabolic phenotype of each offspring was determined, and correlated with number of lung and liver tumors. Both male and female AhbAhd (responsive) offspring in most dose groups presented a consistent two- to three-fold higher incidence of lung tumors than did non-responsive AhdAhd littermates. The difference held for offspring of both (C57BL/6 X DBA)F1 and DBA mothers and it was of statistical significance for one or both sexes at most dosage levels. Hepatocellular tumors were also significantly more frequent in responsive male AhbAhd progeny of (C57BL/6 X DBA/2)F1 mothers than in non-responsive AhdAhd littermates. Progeny of the DBA mothers exhibited significantly more liver and lung tumors than did those of the (C57BL/6 X DBA/2)F1 mothers receiving the same dose. These results suggest that in this model system both maternal and fetal genotype for responsiveness to induction of aromatic hydrocarbon metabolism are important factors modulating fetal carcinogenic risk.

A compact multichamber gas inhalation exposure system for mice

A multi-unit, dynamic flow, inhalation exposure system which is capable of accommodating 12 mice per unit has been described. Components of the system include a mixing board, one or more glass distributing tubes, and detachable glass chamber tubes. The flow of a specified concentration of test gas exits from the mixing board, enters a distributing tube, and is then distributed equally to 12 chamber tubes housing one mouse each. Advantages includes quick equilibration time (10 min), relatively low flow rates (20 l/min per distributing tube), ease of disassembly for cleaning, compact size, modest expense and minimal temperature, pressure and physico-chemical effects.

Analysis of the major metabolite of delta 9-tetrahydrocannabinol in urine. V. Cross-reactivity of selected compounds in a radioimmunoassay

The potential for cross-reactivity of an antiserum used to detect 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid in a urine sample by a radioimmunoassay procedure has been examined. The degrees of cross-reactivity of 41 cannabinoids and non-cannabinoid phenolic constituents of Cannabis have been determined. In general, only (delta 8- or delta 9-THC type) cannabinoids of the dibenzopyran type structure were found to appreciably cross-react with the antiserum. Cross-reactivity was not observed with any non-cannabinoid constituent.

Analysis of the major metabolite of delta 9-tetrahydrocannabinol in urine. IV. A comparison of five methods

Urine samples from 29 subjects were simultaneously analyzed for 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid by five previously published methods. The procedures employed were radioimmunoassay (RIA), enzyme immunoassay (EIA), high performance liquid chromatography (HPLC), gas chromatography with electron capture detector (GC/ECD), and gas chromatography/mass spectrometry (GC/MS). A comparison of the results showed significant correlations between the results obtained by HPLC, GC/ECD, and GC/MS procedures. As anticipated, quantitation by any of these procedures resulted in lower values than those obtained by either of the immunoassays.

Development and evaluation of enteric-coated penicillamine tablets

Commercially available 250-mg penicillamine tablets were converted into enteric-coated tablets. Based on in vitro dissolution and disintegration tests, tablets coated with five layers of a cellulose acetate phthalate formulation by a modified pan coating technique were judged to be superior to other coated tablets. These tablets resisted disintegration in simulated gastric fluid over a 4-h period and disintegrated in an average of 21 min in simulated intestinal fluid. Enteric-coated penicillamine tablets were tested in vivo in nine weanling pigs divided into three groups: a negative control group, a test group dosed with enteric-coated penicillamine tablets, and a positive control group dosed with uncoated tablets. The incidence of GI tract bleeding, as determined by daily occult blood tests of the stools, was significantly less in the animals receiving the enteric-coated tablets when compared with the positive control group. The enteric-coated dosage form appeared to decrease GI tract irritation caused by penicillamine. Plasma concentration-time curves for penicillamine in the pigs were similar in shape to those reported in humans. Atypical double peaks occur in both species. Relative bioavailability of the enteric-coated tablet was found to be 67% when compared with the uncoated tablet. This apparent reduction is probably due to a large intrasubject variation in areas under the plasma concentration-time curves and not to a dosage form effect.

Study of the concentration of the herbicide (2,4-dichlorophenoxy)-acetic acid in coca leaves and paste obtained from plants treated with this herbicide

The herbicide (2,4-dichlorophenoxy)-acetic acid (2,4-D) is considered to be the most cost-effective for eradicating illicit coca plants. Since coca leaves are chewed by the natives of coca producing areas, and, since coca paste and cocaine are widely abused, a study was undertaken to determine whether 2,4-D is translocated into the leaves and transferred to coca paste when coca plants are treated with this herbicide. The study concluded that basal treatment of coca plants with 2,4-D ester resulted in translocation of 2,4-D into the leaves, and this herbicide was detected in high concentrations one week after treatment. Coca paste prepared from leaves obtained from basally treated plants did not contain 2,4-D. Foliage spraying resulted in extremely high concentrations of 2,4-D in the leaves, with significantly high concentrations of the herbicide found one week after spraying. Trace amounts of 2,4-D were detected in coca paste prepared from plants sprayed by the foliage method.