Skin patch

Health and Safety Factors. Results of acute oral toxicity studies of 2-pyrrohdinone on white rats and guinea pigs show the LD q to be 6.5 ml,/kg. Skin patch tests on 200 human subjects indicate that 2-pyrrohdinone is a skin kritant, but there is no indication of sensitising action. It is a mild eye irritant (79). 

Skin Patch-Tested Repellents. SmaU areas of human forearms are marked and treated with smaU amounts of repeUent on a unit area basis to ensure that the treatment rate is always the same between subjects (7). The patches are tested at 0 and 4 hours against smaU numbers (ca 15) of mosquitoes. This method does not consider creep, movement of repeUent across the skin surface, or the iateraction between two chemicals owiag to such lateral movement of chemical. 

Rohsenow DJ, Monti PM, Colby SM, et al Naltrexone treatment for alcoholics effect on cigarette smoking rates. Nicotine Tob Res 5 231-236, 2003 Rose JE, Levin ED Concurrent agonist-antagonist administration for the analysis and treatment of drug dependence. Pharmacol Biochem Behav 41 219—226, 1991 Rose JE, Behm FM, Westman EC, et al Mecamylamine combined with nicotine skin patch facilitates smoking cessation beyond nicontine patch treatment alone. Clin Pharmacol Ther 56 86-99, 1994... 

Dermal Effects. Based on a skin patch test, allergic (contact) dermatitis to methyl parathion occurred in a farmer (Lisi et al. 1987). 

The most frequent causes of allergic contact dermatitis in the United States include plants (poison ivy, poison oak, and poison sumac), metallic salts, organic dyes, plastic resins, rubber additives, and germicides.74 The most common skin patch test allergens found to be positive in patients along with potential sources of exposure are shown in Table 32.1.75 In patients with occupational contact dermatitis who were skin patch tested, the common allergens included carba mix, thiuram mix, formaldehyde, epoxy resin, and nickel.76... 

Permeability coefficients for phenol in isolated skin patches from nude mice have been determined (Behl et al. 1983). The permeability coefficient increased as the concentration of the applied aqueous phenol solution increased doubling the concentration from 20 to 40 g/L resulted in a 12-fold increase in mean permeability coefficient (0.007-0.085 cm/hour). The value obtained for the permeability coefficient when 60 g/L was applied to the skin patch (0.169 cm/hour) was similar to that obtained for skin patches in which the stratum comeum had been removed. It was concluded that phenol concentrations exceeding 20 g/L may destroy a diffusion barrier normally provided by the intact stratum comeum, permitting increased percutaneous absorption. 

Dermal absorption of phenol in the presence of various types of soil was measured in vitro using skin patches from pigs (Skowronski et al. 1994). Maximum phenol penetration occurred between 2 and 4 hours after treatment in all cases. Compared to samples with no soil present, the presence of sandy soil reduced the peak penetration by one-half, and the presence of clay soil reduced peak penetration by two-thirds. 

White HK, Levin ED. (1999). Four-week nicotine skin patch treatment effects on cognitive performance in Alzheimer s disease. Psychopharmacology (Berlin). 143(2) 158-65. 

Rose JE, Behm FM, Westman EC, Kukovich P (2006) Precessation treatment with nicotine skin patch facilitates smoking cessation. Nicotine Tob Res 8(1) 89-101 Ross B, Bluml S (2001) Magnetic resonance spectroscopy of the human brain, Anat Rec 265(2) 54-84... 

RoseJE, BehmFM, Westman EC, KukovichP, Precessation treatment with nicotine skin patch facilitates smoking cessation. Nicotine Tob Res 8 89—101, 2006. 

In standardized testing on rabbit eyes, amyl acetate was graded as only slightly injurious. No evidence of delayed contact hypersensitivity due to 20% amyl acetate was observed in repeat-insult skin patch tests of 211 human subjects. ... 

The dopamine agonist rotigotine, delivered daily through a skin patch, was approved in 2007 by the FDA for treatment of early Parkinson s disease. It supposedly provides more continuous dopaminergic stimulation than oral medication in early disease its efficacy in more advanced disease is less clear. Benefits and side effects are similar to those of other dopamine agonists but reactions may also occur at the application site and are sometimes serious. The product was recalled in 2008 because of crystal formation on the patches, affecting the availability and efficacy of the agonist. 

Dermal Effects. Dermal exposure to diazinon resulted in contact dermatitis in farm workers (Matsushita et al. 1985). But, according to another report, a 1% diazinon solution in a skin patch did not elicit an irritation or cause sensitization in humans (Lisi et al. 1987). 

One percent diazinon in "pet." (presumably petroleum ether) has been tested for allergic reactions by patch tests in 294 volunteers examined after 48 and 72 hours of dermal contact (Lisi et al. 1987). The 1% diazinon solution on a skin patch did not elicit allergic reactions in any of the volunteers studied. 

Most of the drugs shown in Table 7.1 are administered passively in the now familiar skin patches. These devices are carefully engineered in order to ensure that the drug is released at a predetermined rate, often with the use of rate-controlling... 

The most current method of nitroglycerin application is a transdermal device or skin patch. A cross section of such a patch is illustrated in Figure 6. The patch is actually a multi-layered polymer stack. The semipermeable membrane which comes in contact with the skin is usually composed of an ethylene-vinyl acetate copolymer or polypropylene. The reservoir contains the drug in a hydrogel or polymer matrix or solvent (the material must be chosen to insure uniform delivery). Examples of some solvents used include dimethyl sulfoxide (DMSO), sodium lauryl sulfate (SDS - a detergent) and propylene glycol/oleic acid. 

Birth control hormones can also be delivered through the skin using a skin patch. Of 800,000 women using the patch, however, i about a dozen have died from blood clots believed to be related to the patch. Is this an acceptable risk Consider that pregancy itself poses significant risks. In developed nations, for every 100,000 live births there are about 20 maternal deaths. In the developing nations of sub-Saharan Africa, by contrast, the number of maternal deaths per j 100,000 live births is around 920. 

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