Murine teratology and pharmacokinetics of the enantiomers of sodium 2-ethylhexanoate

Effective method for the detection of piroxicam in human plasma using HPLC

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used by the general population to alleviate inflammation and pain after oral surgeries. Piroxicam is among the most commonly used NSAIDs and excels in controlling pain, swelling, trismus and other common symptoms of inflammation. This study aimed to evaluate different concentrations of piroxicam and its major metabolite, 5'-hydroxypiroxicam, in human plasma samples over time using high performance liquid chromatography (HPLC) after liquid-liquid extraction. Briefly, 10 volunteers participated in this study after approval by the Ethics Committee of Bauru School of Dentistry, Universidade de São Paulo - USP, Brazil. Volunteers received a single dose oral of piroxicam (20 mg) and had blood collected at various times following an established protocol. The methodology of liquid-liquid extraction was effective for determining concentrations of piroxicam in plasma using HPLC in 10 out of 10 volunteers while 5'-hydroxypiroxicam was only detected in 2 out of 10 volunteers.

Developmental toxicity of 2-ethylhexyl stearate

2-Ethylhexyl stearate was investigated in an embryo-/foetotoxicity and teratogenicity study on rats according to OECD guidelines for the testing of chemicals (No. 414). Dose levels of 0 (arachidis oil), 100, 300 and 1000mg/kg body weight/day were administered by gavage. Dams tolerated the applied dose levels without any toxic effects. Pre- and post-implantation loss and mean numbers of resorptions were unaffected by treatment. All parameters were comparable with the animals of the control group. Skeletal and visceral investigations revealed no treatment-related malformations. For embryo-/foetotoxicity, teratogenicity and maternal toxicity a NOAEL of 1000mg/kg was deduced.

Differential sensitivity of the SWV and C57BL/6 mouse strains to the teratogenic action of single administrations of cadmium given throughout the period of anterior neuropore closure

When administered to mice during gestation, the heavy metal, cadmium, is known to induce malformations of the neural tube, craniofacial region, limbs, trunk, viscera, and axial skeleton that vary in scope and severity among inbred strains of mice. Two strains, C57BL/6 and SWV, were previously shown to differ in their susceptibility to exencephaly induced by many teratogenic treatments, including sodium 2-ethylhexanoate, hyperthermia, valproic acid, and carbon dioxide, with the SWV strain being consistently more sensitive than the C57BL/6 strain. These findings support the observation of Finnell et al. ([1988] Teratology 38:313-320) of shared hierarchies of relative susceptibility to exencephaly induced by biochemically distinct teratogens, and suggest that the SWV strain would also be more sensitive to exencephaly induced by cadmium. In the present study, pregnant mice from the two strains were exposed to single i.p. injections of cadmium chloride at 4 mg/kg-BW on day 6.5, 7.0, 7.5, 8.0, 8.5, or 9.0 of gestation. Fetuses were removed by cesarean section on day 18 of gestation and scored for malformations. The C57BL/6 strain was observed to be more sensitive than the SWV strain to the induction of exencephaly by cadmium on days 6.5, 7.0, and 8.0, with mean litter percentages of 3.6%, 88.3%, and 62.2%, respectively, compared to 0.0%, 4.1%, and 27.7% for the SWV strain. This finding provides evidence in contrast to the hypothesis of shared hierarchies of sensitivity to teratogen-induced exencephaly. Data on a number of other cadmium-induced malformations are also presented.

Differential prenatal toxicity of one straight-chain and five branched-chain primary alcohols in rats

One straight-chain alcohol (n-octanol) and five branched-chain alcohols [2-ethylhexanol (2-EH), isodecanol, two types of isononanol and a C7-9-11 alcohol] were investigated for developmental effects in Wistar rats at equimolar dose levels (0, 1, 5 and 10 mmol/kg by gavage from gestation day 6 to 15; 10 animals per group). n-Octanol and both isononanols were also investigated in a supplementary experiment at 7.5 mmol/kg/day. Pronounced maternal but no developmental toxicity was achieved with n-octanol. C7-9-11 alcohol, which is a mixture of isomers mostly of a low degree of branching (alpha-methyl), showed no adverse effects at any dose levels. The two types of isononanols (typical mixtures of two different sets of isomers originating from two different production routes) exhibited a marked degree of maternal and foetal toxicity at 7.5 and 10 mmol/kg and slight foetal effects at 5 mmol/kg. Because of maternal toxicity in the top dose, a statistically significant increase in malformations was obtained only in the dose window of 7.5 mmol/kg in the supplementary experiment. Isodecanol (a mixture of different isomers) elicited maternal toxicity at 10 mmol/kg and caused a low incidence of retardations and rare malformations at that dose level. Some maternal signs but no foetal effects were observed at 5 mmol/kg. 2-EH showed strong maternal and also foetal toxicity at 10 mmol/kg and slight maternal and foetal toxicity at 5 mmol/kg. The differential responses to the test materials indicate that, at present, within this chemical class of alcohols, the potential for developmental toxicity has to be investigated case by case for each individual structure.

Differential prenatal toxicity of branched phthalate esters in rats

Several phthalate esters with alcohol moieties ranging from C5-C10 chains were investigated for prenatal toxicity in 10 rats per group after gavage administration of 0, 40, 200 and 1000 mg/kg/day from gestation day 6 to 15. At 1000 mg/kg di(2-ethylhexyl) phthalate showed clear foetotoxicity, embryolethality and teratogenicity. No significant effects were recorded at 40 and 200 mg/kg. Di-711-phthalate, a phthalic ester with linear components and a predominantly alpha-methyl branching type, and di-isopentylphthalate showed a very similar spectrum of effects. Interestingly, the alcohol moiety of di-711-phthalate, 711-alcohol was developmentally inactive in a previous experiment. Di-iso-decylphthalate and three types of di-iso-nonylphthalate showed foetal effects of borderline significance at 1000 mg/kg/day.