Dermal blood flow

Exercise also increases skin circulation and perspiration, which both enhance dermal penetration of compounds into the body. Furthermore, skin lesions, such as wounds and dermatitis, can increase the permeability of the skin to chemicals. Also, exposure of the skin to solvents and removal of skin fat increase dermal penetration of a number of compounds. Compounds penetrate the skin more readily in places where the skin is thin, like the face, hands and scrotum. Increased dermal blood flow due to exercise facilitates the penetration of the skin by chemicals. 

Special attention shall be drawn to the preparation of the excised skin prior to the experiment. Long lag-times encountered with hydrophilic substances, as well as an unfavorable partition of lipophilic compounds into viable skin layers, may require the further separation of the skin into its individual layers [80], Furthermore, the absence of dermal blood flow in vitro may build up a significant hindrance to diffusion [81]. Reducing the membrane thickness will generally reduce experiment times and thus minimize the risk of bacterial contamination. 

Dermal Blood Flow, Lymphatics, and Binding as Determinants of Topical Absorption, Clearance, and Distribution... 

DERMAL BLOOD FLOW, LYMPHATICS, AND BINDING AS DETERMINANTS... 

Riviere and Williams (1992) suggested that when the exchanging capillary volume was increased from 1 to 2 ml and all other model parameters were kept constant, higher solute absorption rates resulted (Figure 13.6). Hence, they snggested that it was possible that increases in percutaneons absorption could be mistakenly attribnted to an increased dermal blood flow when the effect was caused by an increase in the volume of tissue actually perfused. 

Seabra, A., Pankotai, E., Feher, M., Somlai, A., Kiss, L., Biro, L., Szabo, C., Kollai, M., de Oliveira, M., Laeza, Z., 2007. 5 -nitrosoglutathione-containing hydrogel increases dermal blood flow in streptozotocin-induced diabetic rats. British Journal of Dermatology 156, 814-818. 

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