This study was conducted to determine the relative dermal bioavailability (absor
ption), distribution, metabolism, and excretion (ADME) of diiso
pro
panolamine (DIPA), an alcohol amine used in a number of industrial and
personal care
products. Grou
ps of 4 female Fischer 344 rats received either a single bolus i.v. dose of 19.0 mg/kg
p>14p>C-DIPA in water or a dermal a
pplication of 19.5 mg/kg
p>14p>C-DIPA in acetone to an area of 1 cm
p>2p> on the back and covered with a bandage. Time-course blood and excreta were collected and radioactivity determined. Urine was analyzed for DIPA and monoiso
pro
panolamine (MIPA). Following i.v. administration, DIPA was ra
pidly cleared from the
plasma and excreted into urine in a biex
ponential manner (
t1/2α, 0.4 h;
t1/2β, 2.9 h). The levels of radioactivity in
plasma dro
pped below the limit of detection 12 h
post-dosing. A total of 97 ± 4%of the dose was actively excreted in urine by kidney, most (
p://www.sciencedirect.com/scidirimg/entities/223c.gif" alt="not, vert, similar" border=0>71%) within 6 h of dosing, virtually all as
parent com
pound; renal clearance exceeded the glomerular filtration rate. Following dermal a
pplication,
p://www.sciencedirect.com/scidirimg/entities/223c.gif" alt="not, vert, similar" border=0>20%of the dose was absorbed in 48 h with the steady-state
penetration rate of
p://www.sciencedirect.com/scidirimg/entities/223c.gif" alt="not, vert, similar" border=0>0.2%/h. Most (14.4%) of the a
pplied radioactivity was excreted in urine at a relatively constant rate due to the
presence of large amount of the
p>14p>C-DIPA at the a
pplication site. Fecal elimination was <0.2%of the dose. The absorbed DIPA did not accumulate in tissues; only
p://www.sciencedirect.com/scidirimg/entities/223c.gif" alt="not, vert, similar" border=0>0.1%of the administered dose was found in liver and kidney. The absolute systemic dermal bioavailability (dose corrected AUC
dermal/AUC
i.v.) of
p>14p>C-DIPA was 12%. The ADME of DIPA contrasts that of its diethanol analogue, diethanolamine, which dis
plays a broad s
pectrum of toxicity in rats and mice. Toxicologically significant concentrations of DIPA are unlikely to be achieved in the systemic circulation and/or tissues as a result of re
peated dermal a
pplication of
products containing DIPA due to slow absor
ption from the skin, ra
pid unchanged elimination in urine, and majority of the
products contain
p://www.sciencedirect.com/scidirimg/entities/2a7d.gif" alt="less-than-or-equals, slant" border=0>1%DIPA.