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  • 1
    ISSN: 1573-904X
    Keywords: transdermal ; iontophoresis ; prodrug ; DHEA ; skin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The aim of this work was to synthesize ionized dehydroepiandrosterone (DHEA) prodrugs with higher water solubility, useful for iontophoretic transdermal application. Methods. The synthesized derivatives were characterized and tested for sensitivity to chemical and enzymatic hydrolysis. Solid state and solution stability was also determined. Transdermal iontophoretic anodal transport in vitro was studied using excised rabbit skin. Results. Two DHEA ionized prodrugs were synthesized: PRO1, a primary amine derivative, and PRO2, a quaternary ammonium salt. The two derivatives possess higher water solubility and lower octanol/saline partition coefficients than DHEA. Prodrugs were sensitive to enzymatic hydrolysis; in particular the primary amine was hydrolyzed faster than the quaternary salt by esterase from porcine liver in vitro. Transdermal flux of the two prodrugs was slightly higher than the parent drug. In the case of passive diffusion, only DHEA was found in the receptor compartment, indicating the complete breakdown of the prodrug in the skin. Current application gave higher drug flux and a significant amount of prodrug was found in the receptor. Conclusions. The use of ionized prodrugs of DHEA can increase the flux attainable during transdermal anodal iontophoresis by up to 7 times, but they are useful for passive transport as well.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2020-04-28
    Description: This archaeometric study was focused on 28 grey to dark-grey lava artifacts found in Ustica Island (Southern Tyrrhenian Sea, Italy) and referable to different grinding tools: saddle querns, rotary Morgantina-type millstones, rotary hand-mills and one small mortar. Mineralogy, petrography and bulk rock geochemical analyses emphasized that most of the grinding artifacts belonged to the Na-Alkaline series of Ustica, mainly basalts, hawaiites and mugearites. Nevertheless, some millstone samples did not match major and trace elements of Ustica lavas, in particular, one high-TiO2 Na-Alkaline basalt from Pantelleria Island, some tholeiitic/transitional basalts from the Iblei Mountains and one Calcalkaline basaltic andesite, most likely from the Aeolian Archipelago. The Hellenistic–Roman re-colonisation of Ustica Island, after ca. one millennium of nearly complete abandonment, was testified by the import of the non-local Morgantina-type rotary millstones, very widespread in the Mediterranean area from 4th–3rd century BC. This import of millstones represented, for the Ustica inhabitants, a real breakthrough for developing a local production of grinding artifacts on the basis of the new rotary technique which was much more efficient than that of the archaic saddle querns, largely used in the Middle Bronze Age. The results are also discussed in the framework of the overall volcanic millstone trade in the Mediterranean area and the different milling technology in antiquity.
    Description: Published
    Description: id 389
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Description: JCR Journal
    Keywords: grinding tools ; lavas ; magmatic series ; Hellenistic–Roman period ; Morgantina-type rotary millstones ; Mediterranean ; Ustica
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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