Pharmacokinetics of intra-amniotically administered hyperosmolar urea in rhesus monkeys

Blake, David A.; Burnett, Lonnie S.; Miyasaki, Barbara C.; Longstreth, James; King, Theodore M.

doi:10.1016/0002-9378(76)90151-4

Cited by 7 publications

(3 citation statements)

References 13 publications

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“…Pharmacokinetics of three-compartment fit of urea concentration and excretion data (Blake et al 1976b) Compartment vessels vs. intact vitelline vessels (1.2 × 10 −3 ±3.8×10 −4 versus 1.0 × 10 −3 ± 2.7 × 10 −4 ml/g/s, N = 5) were not significant. The permeability of chorioallantoic placenta of the guinea pig as a function of molecular dimension was 1.1 × 10 −3 ± 2.1 × 10 −4 ml/g/s (N = 8).…”

Section: Tablementioning

confidence: 82%

“…Plasma concentration and urine elimination data are given in Tables 3a and 3b, respectively (Bourne and Barber 1972). Blake et al (1976b) injected three mid-gestation rhesus monkeys directly into the amniotic fluid with [ 14 C]Urea (58% w/v, 2.3 g/kg, 25 μCi). Amniotic fluid and blood were obtained before and at 7.…”

Section: Distributionmentioning

confidence: 99%

“…The rate constant for transfer of Urea from the amniotic fluid to the fetal compartment was independent of the concentration in amniotic fluid. Excretion data are presented in Table 4 (Blake et al 1976b). Thornburg and Faber (1977) ligated the branch point of the vitelline vessel of pregnant guinea pigs 1 to 20 days before the experiment.…”

Section: Table 3amentioning

confidence: 99%

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Niacinamide (aka nicotinamide) and Niacin (aka nicotinic acid) are heterocyclic aromatic compounds which function in cosmetics primarily as hair and skin conditioning agents. Niacinamide is used in around 30 cosmetic formulations including shampoos, hair tonics, skin moisturizers, and cleansing formulations. Niacin is used in a few similar product types. The concentration of use of Niacinamide varies from a low of 0.0001% in night preparations to a high of 3% in body and hand creams, lotions, powders and sprays. Niacin concentrations of use range from 0.01% in body and hand creams, lotions, powders and sprays to 0.1% in paste masks (mud packs). Both ingredients are accepted for use in cosmetics in Japan and the European Union. Both are GRAS direct food additives and nutrient and/or dietary supplements. Niacinamide may be used in clinical treatment of hypercholesteremia and Niacin in prevention of pellegra and treatment of certain psychological disorders. Both ingredients are readily absorbed from skin, blood, and the intestines and widely distribute throughout the body. Metabolites include N1-methylnicotinamide and N1-methyl-4-pyridone-3-carboxamide. Excretion is primarily through the urinary tract. While Niacinamide is more toxic than Niacin in acute toxicity studies, both are relatively non-toxic. Short-term oral, parenteral, or dermal toxicity studies did not identify significant irreversible effects. Niacinamide, evaluated in an in vitro test to predict ocular irritation, was not an acute ocular hazard. Animal testing of Niacinamide in rabbits in actual formulations produced mostly non-irritant reactions, with only some marginally irritating responses. Skin irritation tests of up to 2.5% Niacinamide in rabbits produced only marginal irritation. Skin sensitization tests of Niacinamide at 5% during induction and 20% during challenge were negative in guinea pigs. Neither cosmetic ingredient was mutagenic in Ames tests, with or without metabolic activation. Niacinamide and Niacin at 2 mg/ml were negative in a chromosome aberration test in Chinese hamster ovary cells, but did produce large structural chromosome aberrations at 3 mg/ml. Niacinamide induced sister chromatid exchanges in Chinese hamster ovary cells, but Niacin did not. Under certain circumstances, Niacinamide can cause an increase in unscheduled DNA synthesis in human lymphocytes treated with UV or a nitrosoguanidine compound. Niacinamide itself was not carcinogenic when administered (1%) in the drinking water of mice. No data on the carcinogenic effect of Niacin were available. Niacinamide can moderate the induction of tumors by established carcinogens. Niacinamide in combination with streptozotocin (a nitrosourea compound) or with heliotrine (a pyrrolizidine alkaloid), produced pancreatic islet tumors. On the other hand, Niacinamide reduced the renal adenomas produced by streptozotocin; and intestinal and bladder tumors induced by a preparation of bracken fern. Niacinamide evaluated in in vitro test systems did affect development, but Niacinamide re...

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Section: Tablementioning

confidence: 82%

Section: Distributionmentioning

confidence: 99%