Human post-mortem skin was exposed in vitro to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at 32 degrees C, under controlled humidity. In one-half of the samples, damage to the surface of the skin was simulated by stripping of the stratum corneum. After incubation with TCDD for 100 min, four different decontamination protocols were performed: (1) the sample was wiped with dry, adsorbent material (cotton balls); (2) a 10-min topical treatment with mineral oil was followed by dry wiping with cotton balls; (3) a 10-min topical treatment with mineral oil was followed by wiping with acetone-soaked cotton balls; and (4) the sample was washed with water and soap. After decontamination, skin samples were incubated (up to 300 min) again at 32 degrees C. One set of both intact and stripped TCDD-exposed skin samples was incubated for 300 min--absent decontamination--and was used as a control. Mineral oil treatment and acetone wipes, or water and soap, were effective in reducing (i.e., about two-fold) the amount of TCDD in the stratum corneum of intact skin. Mineral oil plus dry wipes reduced the amount of TCDD in the stratum corneum by about one-third, whereas dry wiping alone was ineffective. All protocols, however, were similarly effective in reducing the amount of TCDD in the epidermis and upper dermis; TCDD concentrations were decreased locally by factors of up to ten. In the lower dermis, a minimal effect of the decontamination procedures was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetone↗

PubMedDate not supplied

Penetration of vitamin A acid into human skin.

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1-Propanol↗

PubMedDate not supplied

Adverse reactions of externally applied drugs and inert substances.

The lack of a first-pass effect for locally-applied substances is often not considered. This is especially true for such central nervous system agents as salicylic acid, hexachlorophene or caffeine which have a relatively low toxicity when applied orally. Manifestation of dermal irritation, such as a beginning rash or inflammation, are often tolerated because the beneficial effects of some topically applied substances outweight the damage (Dithranol, 5-Fluorouracil). This applies to some anti-phlogistics as well, which may also cause skin irritation. Some substances, such as benzoyl peroxide, vitamin-A acid and beta-estradiol have direct or indirect desiccative effects so that skin irritations may occur. Other substances, such as tar, for example, are applied locally although they may have a carcinogenic potential when misused, or when contraindications for its use are disregarded. Local risks can be recognized in clinical-experimental and clinical testing of dermatological products. One must, however, look carefully for an intensification of possible risks related to the method of application, the condition of the skin, the site of application, supporting therapeutic measures or changes in the composition of the vehicle. Lanolin, cetyl alcohol and myristyl alcohol, sorbitol, isopropyl-myristate as well as polyethylene glycols (PEG) penetrate the skin like active substances. Some have been connected with skin allergies. In addition, some preservatives have mutagenic properties. Many vehicles cause dehydration of the horny layer and thus result in chronic surface damage. This is true for hygroscopic substances such as PEG as well as for liquid paraffins, lipid solvents (alcohol, acetone), solvents such as propylene glycol and for some O/W emulsifiers.

Administration, Topical↗