摘要:

SummaryThe interactions between a typical range of perfume materials, alcohol, water, air, elevated temperatures and daylight have been studied. The changes of composition, acidity, peroxide content and the formation of new molecules were followed. The stabilizing effects of UV absorbers, antioxidants and sequestering agents were examined;— the formation of acid reaction products was accelerated by air, temperature, daylight and the presence of natural products;— peroxide formation was accelerated by heat and light and the presence of air; as the acidity increased, the peroxides decomposed;— the acetalization of other aldehydes was accelerated by temperature and daylight and the presence of natural products up to 40% of certain aldehydes may be converted into acetals after 3 months at 37°C;— many stereoisomerizations occur, e.g., transisoeugenol is converted up to 10% into the cis isomer after 3 months at 37°C and 58% in daylight;— evaluation of antioxidants UV absorbers and sequestering agents showed a significant protection against deterioration only by EDTA dipotassium salt;— ethanol was converted into acetaldehyde and its diethylacetal by peroxides present and formed on ageing up to 0.08%. Natural products accelerated this formation;— the reaction between benzoyl peroxide and ethanol was shown to yield up to 63% of acetaldehyde+diethyl acetal whilst di‐t‐butyl peroxide gave only 23% under the same conditions.These results go some way to explaining odour change

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1987.tb00475.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe activity of thioglycolic acid, incorporated in a microemulsion, towards cystine residues present in keratin proteins has been investigated.In an attempt to relate the structural state of the microemulsions to cystine reactivity, an appropriate model system showing a large microemulsion domain with diverse structures was chosen.The realm of preferentially hydrocarbon‐continuous microemulsion‐type media was found to induce the highest activ

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1987.tb00476.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SynopsisThe percutaneous permeation of two oxidative hair dyes was measured by means of pig skin in a flow‐through diffusion cell system entirely constructed from Teflon. Pig skin membranes were prepared by reducing full thickness skin with a dermatome to a morein vivo‐like barrier layer and their integrity was checked by measuring the steady‐state permeation of tritiated water. Initially, the inter‐ and intraindividual variability of percutaneous permeation was determined with an aqueous solution of 1‐(2′‐hydroxyethyl)‐amino‐3,4‐methylenedioxybenzene‐hydrochloride, an oxidative hair dye component. In the same way the proper flow rate of elution fluid through the receptor cell was found to be most favourable at 10 ml h‐1, the thickness of permeation membranes was fixed at 1 mm, and it was shown that storage of the skin at −20°C for up to 35 days did not change the permeability. The percutaneous permeation of the same hair dye component and of 4‐amino‐2‐hydroxymethylphenol‐hydrochloride was determined after application to pig skin membranes under practical conditions of hair dyeing. Thein vitroskin permeation was in the same order of magnitude as results from comparablein vivoskin absorption studies in rats.Perméation percutanéein vitro

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1987.tb00477.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SynopsisA phenomenon of increased permeation as a function of time in the percutaneous absorption of urea and water led to thisin vitrostudy with skin of hairless mice in a closed diffusion cell system. The Latin square method was used to assess the effect of four variables, namely temperature, time of hydration, concentration of urea and stirring of the donor‐and receiver‐cell phases on the physical structure of the skin and the permeability coefficients of urea and water. The scanning electron microscope and the transmission electron microscope were used to assess the physical changes in skin structure.Temperature and time of hydration, but not the concentration of urea or the stirring of the donor‐ and receiver‐cell phases, affected the permeability of the skin to urea and water. The scanning electron microscope and transmission electron microscope micrographs confirmed these

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1987.tb00478.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1987.tb00479.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1987.tb00480.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY