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Advanced Drug Delivery Reviews Jan 2020In this two-part review we present an up-to-date description of different imaging methods available to map the localization of drugs on skin as a complement of...
In this two-part review we present an up-to-date description of different imaging methods available to map the localization of drugs on skin as a complement of established ex-vivo absorption studies. This first part deals with invasive methods which are grouped in two classes according to their underlying principles: i) methods using radioactivity such as autoradiography and ii) mass spectrometry methods such as MALDI and SIMS. For each method, a description of the principle is given along with example applications of imaging and quantifying drug delivery in human skin. Thanks to these techniques a better assessment of the fate of drugs is obtained: its localization on a particular skin structure, its potential accumulation, etc. A critical comparison in terms of capabilities, sensitivity and practical applicability is included that will help the reader to select the most appropriate technique depending on the particular problem to be solved.
Topics: Administration, Cutaneous; Autoradiography; Dermatologic Agents; Drug Delivery Systems; Humans; Mass Spectrometry; Models, Biological; Skin; Skin Absorption; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 31778729
DOI: 10.1016/j.addr.2019.11.004 -
Neuroscience and Biobehavioral Reviews Nov 2019A major hypothesis in the addiction field suggests deficits in dopamine signaling during abstinence as a driving mechanism for the relapsing course of the disorder....
A major hypothesis in the addiction field suggests deficits in dopamine signaling during abstinence as a driving mechanism for the relapsing course of the disorder. Paradoxically, blockade of mu-opioid receptors (MORs) intended to suppress dopamine release and alcohol reward is a widely used treatment for preventing relapse in alcohol use disorder (AUD). To elucidate this apparent discrepancy, we systematically survey the literature on experimental studies in AUD subjects and animal models, which assessed striatal dopamine levels and D1, D2-like receptor, dopamine transporter and MOR via positron emission tomography (PET) and ex vivo receptor binding assays. The reported evidence indicates a changing dopaminergic signaling over time, which is associated with concomitant alterations in MOR, thus suggesting a highly dynamic regulation of the reward system during abstinence. Such a view can reconcile the various evidences from in vivo and postmortem studies, but makes developing an effective pharmacological intervention that specifically targets either dopamine receptors or the transporter system a daunting task.
Topics: Alcoholism; Animals; Autopsy; Craving; Humans; Positron-Emission Tomography; Receptors, Dopamine; Receptors, Opioid, mu; Reward
PubMed: 30243576
DOI: 10.1016/j.neubiorev.2018.09.010 -
Advanced Drug Delivery Reviews Jan 2020Understanding the delivery and diffusion of topically-applied drugs on human skin is of paramount importance in both pharmaceutical and cosmetics research. This...
Understanding the delivery and diffusion of topically-applied drugs on human skin is of paramount importance in both pharmaceutical and cosmetics research. This information is critical in early stages of drug development and allows the identification of the most promising ingredients delivered at optimal concentrations to their target skin compartments. Different skin imaging methods, invasive and non-invasive, are available to characterize and quantify the spatiotemporal distribution of a drug within ex vivo and in vivo human skin. The first part of this review detailed invasive imaging methods (autoradiography, MALDI and SIMS). This second part reviews non-invasive imaging methods that can be applied in vivo: i) fluorescence (conventional, confocal, and multiphoton) and second harmonic generation microscopies and ii) vibrational spectroscopic imaging methods (infrared, confocal Raman, and coherent Raman scattering microscopies). Finally, a flow chart for the selection of imaging methods is presented to guide human skin ex vivo and in vivo drug delivery studies.
Topics: Animals; Dermatologic Agents; Drug Delivery Systems; Humans; Models, Animal; Models, Biological; Optical Imaging; Skin; Skin Absorption; Spectrum Analysis
PubMed: 32217069
DOI: 10.1016/j.addr.2020.03.003