Radioactive skin contamination with radionuclides in ionic forms after the permeation across skin models was studied in vitro. Using animal skin models of 5-day-old rat and 9-day-old rat, either intact or stripped, it was found that besides the transepidermal also the transfolicular flux can be important. Stratum corneum was found to be the principal permeation barrier in all cases. The study of penetration — time profiles revealed that permeated amounts were proportional to time in the case of 137Cs+ and 60Co2+, but they showed a local maximum in the case of 147Pm3+.
Co2+ ion penetration at different concentrations across animal models of human skin-five days old rat skin (without hairs) and
nine days old rat skin (with hairs)—was studied in vitro in vertical diffusion cells. The results showed that the permeated
amounts of Co2+ ions are proportional to its concentration in donor solutions, whereby permeated fractions are higher at lower concentrations.
Results confirmed that the most important barrier against the penetration of ions is horny layer of the skin.
Permeation of metal Cs+ ions from water solutions across the intact, stripped and splitted skin of 5- or 9-day old rat was studiedin vitro using vertical diffusion cells. The results showed that the stratum corneum (horny layer) of this new animal skin model represents
the principal pentration barrier. The relative importance of the percutaneous absorption of Cs+ ions through transepidermal and transfolicular routes has been assessed comparing the penetration across skin without hairs
and skin just haired. The results have shown that the shunt diffusion along hair follicles can be of preponderant value.
A quantitative separation scheme for 15 radionuclides is presented. The scheme is based on group separation by means of anion-exchange
resins using mixed solvent systems and subsequent separation of the groups into individual components by means of change of
both eluting agent and resin type. The optimum working conditions for separation are established. Separation procedures are
of good reproducibility and practically quantitative.
Authors:V. Koprda, P. Bohov, J. Smisterová, and L. Boháčik
Three methods of atropine and scopolamine determination in transdermal permeation have been developed. Radiometric determination seems to be an excellent, quick and extremely sensitive method, which ought to be preferred when working with biological systems. The radioreceptor analysis is of group specificity. It can be used to advantage in monitoring atropine plasma concentrations exceeding 1.5 ng cm–3 and scopolamine concentrations above 50 pg cm–3. GC/MS provides adequate specificity and sensitivity for the determination of therapeutic levels of atropine and scopolamine in blood. The sensitivity of this method is approximately 1–2 ng cm–3.
Authors:Z. Kassai, V. Koprda, K. Bauerová, M. Harangozó, P. Bendová, A. Bujnová, and A. Kassai
The composition and the permeation properties of the skin are dependent on age. In the animal models for permation studies, age affects the mechanical as well as the permeation properties significantly. The time dependence of permeation of 147Pm3+ from aqueous solution was established by the animal skin model and the age dependence of promethium permeation through the skin was examined. The aim was to find the optimum rat skin age model for radionuclide permeation studies and to assess the relative importance of the main permeation pathways: transepidermal and transfollicular permeation. The skin from 5-day-old rats (5DR) was found to represent the optimum animal model to study transepidermal permeation of ions. The skin from 9-day-old rats (9DR) was selected to study transfollicular permeation of ions. Comparison of the permeated amounts of promethium through the skin without hairs (3 DR to 6 DR) and with hairs (7DR to 12DR) showed that the additional permation mode via follicles significantly contributed to the permeation rate and extent.