Isolated human/animal stratum corneum as a partial model for 15 steps in percutaneous absorption: emphasizing decontamination, Part I

2012 ◽  
Vol 33 (3) ◽  
pp. 157-172 ◽  
Author(s):  
Xiaoying Hui ◽  
Sonia Lamel ◽  
Peter Qiao ◽  
Howard I. Maibach
Keyword(s):  
Stratum Corneum ◽  
Percutaneous Absorption ◽  
Partial Model ◽  
Human Animal

The percutaneous absorption and skin distribution of lindane in man

1997 ◽  
Vol 16 (11) ◽  
pp. 645-651 ◽  
Author(s):  
Ian P Dick ◽  
Peter G Blain ◽  
Faith M Williams
Keyword(s):  
Stratum Corneum ◽  
Percutaneous Absorption ◽  
Peak Plasma ◽  
Plasma Concentrations ◽  
Systemic Circulation ◽  
White Spirit ◽  
Application Site ◽  
Small Areas ◽  
Exposure Site ◽  
Applied Dose

1 The absorption and distribution of lindane through skin was examined using human volunteers. Two different preparations were employed, one with acetone as the vehicle and the other, a commercial product, consisting primarily of white spirit as the solvent base. 2 The mean peak plasma concentrations of lindane following exposure to the acetone and white-spirit based applications were 0.91 and 0.47 ng/ml, respec tively. The similarity between these levels did not reflect the 40-fold higher dose of lindane in the acetone vehicle. White spirit enhanced the penetration of lindane with respect to the acetone vehicle, high lighting the influence of vehicle upon percutaneous absorption. Low levels of trichlorophenol glucuronide metabolites, but no lindane, were detected in the urine. 3 The exposure site was washed at 6 h to mimic a decontamination procedure at the end of a working day. The proportion of the applied dose unabsorbed by 6 h was 80% and 10% for the acetone and the white spirit-based formulation, respectively. Small areas of the exposed site were tape stripped at 6 and 24 h to assess any lindane that may be associated with the stratum corneum. High levels were observed in the stratum corneum at 6 h exposure (up to 30% of the applied dose for the white spirit based formulation). However, this level had decreased by 24 h (by at least 90% of the amount found at 6 h). A gauze or gauze/shirt combination covering the application site between 6 and 24 h did account for some of this loss of lindane from the stratum corneum attributed to friction and removal of exfoliated cells. The unaccounted propor tion was presumed to have been absorbed through the skin into the systemic circulation. This demonstrates the absorption of chemicals can occur from a depot in the stratum corneum even following a wash proce dure.

scholarly journals Pharmacokinetics of Buprenorphine Hydrochloride (BN HCl). (2): Role of Stratum Corneum in Percutaneous Absorption of TSN-09 (BN HCl containing tape) in Male Rats.

2001 ◽  
Vol 16 (6) ◽  
pp. 584-589
Author(s):  
Yasuhiro TAKAHASHI ◽  
Shigeyuki ISHII ◽  
Hironori ARIZONO ◽  
Shin-ichi NISHIMURA ◽  
Noriyuki SAITO ◽  
...  
Keyword(s):  
Stratum Corneum ◽  
Percutaneous Absorption ◽  
Male Rats

scholarly journals Raman and AFM-IR chemical imaging of stratum corneum model membranes

2020 ◽  
Vol 98 (9) ◽  
pp. 495-501
Author(s):  
Adrian Paz Ramos ◽  
Gert Gooris ◽  
Joke Bouwstra ◽  
Michael Molinari ◽  
Michel Lafleur
Keyword(s):  
Fatty Acids ◽  
Stratum Corneum ◽  
Free Fatty Acids ◽  
Percutaneous Absorption ◽  
Lipid Fraction ◽  
Chemical Imaging ◽  
Raman Microspectroscopy ◽  
Central Layer ◽  
Lipid Matrix ◽  
Lipid Environment

Stratum corneum (SC), the outermost layer of the epidermis, is the primary barrier to percutaneous absorption. The diffusion of substances through the skin occurs through the SC lipid fraction, which is essentially constituted of an equimolar mixture of ceramides, free fatty acids, and cholesterol. The lipid constituents of SC are mainly forming continuous multilamellar membranes in the solid/crystalline state. However, recent findings suggest the presence of a highly disordered (liquid) phase formed by the unsaturated C18 chain of ceramide EOS, surrounded by a highly ordered lipid environment. The aim of the present work was to study the lipid spatial distribution of model SC membranes composed of ceramide EOS, ceramide NS, a mixture of free fatty acids, and cholesterol, using Raman microspectroscopy and AFM-IR spectroscopy techniques. The enhanced spatial resolution at the tens of nanometers scale of the AFM-IR technique revealed that the lipid matrix is overall homogeneous, with the presence of small, slightly enriched, and depleted regions in a lipid component. No liquid domains of ceramide EOS were observed at this scale, a result that is consistent with the model proposing that the oleate nanodrops are concentrated in the central layer of the three-layer organization of the SC membranes forming the long periodicity phase. In addition, both Raman microspectroscopy and AFM-IR techniques confirmed the fluid nature of the unsaturated chain of ceramide EOS while the rest of the lipid matrix was found highly ordered.

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