Percutaneous absorption of<i>cis‐</i>and<i>trans</i>‐permethrin in rhesus monkeys and rats: Anatomic site and interspecies variation

Sidon, Edward W.; Moody, Richard P.; Franklin, Claire A.

doi:10.1080/15287398809531107

Cited by 36 publications

(17 citation statements)

References 26 publications

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“…The value (1.967) predicted by the Potts and Guy (1992) equation is 7.5 Â 10 7 greater. However, the results of in vivo rat absorption studies (43-46% over 7-14 days) conducted by Sidon et al (1988) appear to produce similar results to the high Potts and Guy (1992) K p value for permethrin. According to Farahmand and Maibach (2009), in vitro estimates may be improved when vehicle effect is considered and studies are carried out under steady-state conditions.…”

Section: Skin Permeation Constantssupporting

confidence: 82%

“…This value is 7.5 Â 10 7 greater than the value reported by Bast et al (1997). Additional work is needed to determine whether the high results of Sidon et al (1988) are inconsistent with the Bast et al (1997) value. At present the absorption K p s for the pyrethroids appear to be extremely low, based on the rat in vivo studies of Scott and Ramsay (1987) with cypermethrin and in vitro studies with isolated rat and human skin.…”

Section: Discussioncontrasting

confidence: 65%

“…Several percutaneous studies with the pyrethroids strongly support the belief that these insecticides are not readily absorbed, but remain on the surface of the skin until they are washed off. In one particular study (Sidon et al 1988) the high levels of permethrin absorption through the forehead skin (24-28%) of the monkey was reported over a 7-to 14-days period. Wester et al (1994) reported an absorption of 1.9% of pyrethrin that had been applied to the forearm of human volunteers over a 7-days period.…”

Section: Discussionmentioning

confidence: 95%

“…Bast et al (1997) calculated a K p value of 2.63 Â 10 À8 Á cm Á h À1 for permethrin. Moreover, Bast et al (1997) commented on the high permeability data of Sidon et al (1988) involving permethrin, which they thought defied interpretation. From the QSAR equation of Potts and Guy (1992) a percutaneous K p (cm Á h À1 ) for permethrin was predicted to be 1.967.…”

Section: Discussionmentioning

confidence: 97%

“…3.8 Dermal Dose-Response, Pharmacokinetic, and Metabolism Studies Sidon et al (1988) developed 7-or 14-days dermal absorption data in Rhesus monkeys and Sprague-Dawley rats using permethrin (cis and trans isomers) labeled with 14 C in the alcohol and cyclopropyl groups. Permethrin was applied to the forehead or forearm of the monkey and to the mid-lumbosacral region of the rat.…”

Section: Skin:blood Partition Coefficientsmentioning

confidence: 99%

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Parameters for Pyrethroid Insecticide QSAR and PBPK/PD Models for Human Risk Assessment

Knaak

Dary²,

Zhang

et al. 2012

Reviews of Environmental Contamination and Toxicology

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In this review we have examined the status of parameters required by pyrethroid QSAR-PBPK/PD models for assessing health risks. In lieu of the chemical,biological, biochemical, and toxicological information developed on the pyrethroids since 1968, the finding of suitable parameters for QSAR and PBPK/PD model development was a monumental task. The most useful information obtained came from rat toxicokinetic studies (i.e., absorption, distribution, and excretion), metabolism studies with 14C-cyclopropane- and alcohol-labeled pyrethroids, the use of known chiral isomers in the metabolism studies and their relation to commercial products. In this review we identify the individual chiralisomers that have been used in published studies and the chiral HPLC columns available for separating them. Chiral HPLC columns are necessary for isomer identification and for developing kinetic values (Vm,, and Kin) for pyrethroid hydroxylation. Early investigators synthesized analytical standards for key pyrethroid metabolites, and these were used to confirm the identity of urinary etabolites, by using TLC. These analytical standards no longer exist, and muste resynthesized if further studies on the kinetics of the metabolism of pyrethroids are to be undertaken.In an attempt to circumvent the availability of analytical standards, several CYP450 studies were carried out using the substrate depletion method. This approach does not provide information on the products formed downstream, and may be of limited use in developing human environmental exposure PBPK/PD models that require extensive urinary metabolite data. Hydrolytic standards (i.e., alcohols and acids) were available to investigators who studied the carboxylesterase-catalyzed hydrolysis of several pyrethroid insecticides. The data generated in these studies are suitable for use in developing human exposure PBPK/PD models.Tissue:blood partition coefficients were developed for the parent pyrethroids and their metabolites, by using a published mechanistic model introduced by Poulin and Thiele (2002a; b) and log DpH 7.4 values. The estimated coefficients, especially those of adipose tissue, were too high and had to be corrected by using a procedure in which the proportion of parent or metabolite residues that are unbound to plasma albumin is considered, as described in the GastroPlus model (Simulations Plus, Inc.,Lancaster, CA). The literature suggested that Km values be adjusted by multiplying Km by the substrate (decimal amount) that is unbound to microsomal or CYPprotein. Mirfazaelian et al. (2006) used flow- and diffusion-limited compartments in their deltamethrin model. The addition of permeability areas (PA) having diffusion limits, such as the fat and slowly perfused compartments, enabled the investigators to bring model predictions in line with in vivo data.There appears to be large differences in the manner and rate of absorption of the pyrethroids from the gastrointestinal tract, implying that GI advanced compartmental transit models (ACAT) need to be included in PBPK mo...

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Section: Skin Permeation Constantssupporting

confidence: 82%