Pharmacokinetic modelling of the plasma concentration-time profile of the vitamin retinyl palmitate following intramuscular administration.
Seven healthy male volunteers (21-24 y) received by the ventro-gluteal route a single dose of 100,000 I.U. of the vitamin retinyl palmitate (RP) in a water-miscible preparation (W) and 5 weeks later the same dose in an oily solution (S). After administration of W median (range) peak plasma concentrations of 5.6 (4.4-8.7). 10(3) micrograms l-1 were reached after 12 h and high levels persisted for another 50 h. At 144 h levels were still, by a factor 3, higher than baseline. Plasma levels of RP after S remained close to baseline (20-50 micrograms.l-1) suggesting negligibly low bioavailability. The plasma level profile of RP after W could well be described by use of a one-compartment model with Weibull-type absorption and Michaelis-Menten elimination. The median (range) absolute bio-availability (estimates of lower limits) was 42 (32-52) per cent.
Hartmann
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Pharma Clinical Research, F. Hoffmann-La Roche Ltd., Basle, Switzerland.
Gysel
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Dubach
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UC
Forgo
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I
D000328:Adult; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D004224:Diterpenes; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008954:Models, Biological; D012044:Regression Analysis; D000084562:Retinyl Esters; D013050:Spectrometry, Fluorescence; D014801:Vitamin A / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics
D004224:Diterpenes; D000084562:Retinyl Esters; D014801:Vitamin A; C014794:retinol palmitate