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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of cosmetic science 10 (1988), S. 0 
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In continuation of previous studies on keratin-substantive sunscreens, two series of quaternary ammonium compounds, derived from 2,4-dihydroxy and from 4-hydroxybenzophenone and containing O-alkyl and N-alkyl chains of different length were prepared and submitted to substantivity tests on wool, to microbiological tests on two bacterial and two fungal species, and to tests for allergenicity/irritation on human skin. All compounds were rapidly adsorbed by wool in aqueous solution: as expected, the maximum amounts adsorbed at equilibrium (Smax), indicative of the skin substantivity, were greatest for the C12 N-alkyl derivatives, and showed a progressive decrease with increasing length of the N-alkyl substituent. No substantial substantivity differences were detected in four C12 quaternary derivatives, differing by the presence (or absence) of a 2-OH group in the benzophenone moiety and by the length of the O-alkyl (n= 2 or 3) side chain. When tested for antimicrobial activity, however, only the 4-hydroxybenzophenone C12 quaternary derivatives showed an order of activity comparable with that of two reference compounds. The conditions leading to a maximal antibacterial activity in the present compounds appeared to be the absence of the 2-OH group, and a shorter O-alkyl side chain. None of the new quaternary derivatives showed skin-irritant properties. The results of this investigation, while confirming the peak substantivity of C12 quaternary derivatives, indicate the possibility of dissociating, in a quaternary ammonium sunscreen, the skin substantivity from other unwanted side-effects, and offer some guidelines for the development of safer agents of this type.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of cosmetic science 8 (1986), S. 0 
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Two series of quaternary ammonium UV-B sunscreens, derived from salicylic acid (S) and from p-methoxycinnamic acid (C), and containing N-alkyl chains of different length (C2 to C16) were prepared and submitted to substantivity tests on animal (wool) keratin, and to microbiological tests. A direct correlation between substantivity and antimicrobial/antifungal activity was observed in all cases, the compounds bearing C12 alkyl chains displaying peak values. The C-derivatives, when compared with the S-derivatives, showed relatively higher substantivity and sunscreen index (SI) values, coupled with lower antibacterial activity. The substantivity-microbiological activity correlations and the particular behaviour of the C12 derivatives are briefly discussed in the light of the existing literature data. On the basis of the experimental results, possible guidelines for the development of substantive and non-antibacterial (and possibly, non-irritant) quaternary ammonium sunscreens are indicated. La substantivité des filtres solaires
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of cosmetic science 5 (1983), S. 0 
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Il est bien acquis que le 5-méthoxypsoralène (5-MOP, bergaptène) contenu dans l'essence de bergamote exerce plusieurs actions biologiques à la suite d'irradiation en lumière UV-longue (UV-A, λ 〉 320 nm). Cette étude a eu pour but de vérifier si la réponse phototoxique, déclenchée chez le cobaye à la suite d'application cutanée de 5-MOP suivie par rayonnement UV, peut être réduite ou même annulée par l'application simultanée de substances absorbant les rayons UV-A. Les solutions photosensibilisatrices employées étaient (a) une solution alcoolique de 5-MOP, (b) de l'essence de bergamote diluée, et (c) un parfum expérimental. Parmi les filtres qui ont été essayés, deux dérivés du dibenzoylméthane se sont révelés particulièrement efficaces. On a observé que l'activité protectrice de ces filtres augmente de façon significative lorsqu'ils sont dissous dans l'essence de bergamote, ou dans le parfum, par rapport à l'activité demontrée dans la solution alcoolique de 5-MOP. Un dérivé du distirylbiphényle possédant un maximum d'absorption à 350 nm s'est révelé particulièrement actif. Inhibition of bergaptene toxicity by UV-A filters
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of cosmetic science 2 (1980), S. 0 
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A method for measuring the variation of electrical impedance (Z) of thin layers (0.1 mm) of O/W emulsions during evaporation in a controlled environment is presented. The evaporation of an emulsion base (A) either as such and containing 1% glycerin (B) or 1% sodium pyrrolidonecarboxylate (C) was investigated for 120 min at constant air temperature (25°C) and relative humidity (55%). The measured impedance of the emulsion layers increased by three orders of magnitude during the evaporation cycles. The relationship between impedance and water content of the evaporating emulsion layers was investigated. Each emulsion showed a complex linear relationship between log Z and water content, the relationship being represented by two (three, for emulsion A) linear portions in the graph. Plots of water content vs. time, temperature vs. time and rate of water loss vs. water content of the emulsion layers are presented. The data appear to indicate that evaporation proceeds via distinct stages, whose correspondence to different mechanisms of water evaporation is discussed. The potentiality of the present method for water analysis, and for investigating structural changes in emulsions during evaporation, is also discussed. Les variations d'impédance électrique et la teneur en eau d'émulsions huile dans eau en cours d'évaporation
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of medicinal chemistry 11 (1968), S. 904-907 
    ISSN: 1520-4804
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 33 (1968), S. 2884-2887 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1435-702X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An objective in the development of ophthalmic formulations is the use of in vitro or animal models that closely resemble the clinical situation. For this reason, experiments with conventional pilocarpine nitrate eyedrops and a depot formulation of pilocarpine nitrate sorbed to poly (butylcyanoacrylate) nanoparticles were carried out. In vitro, the diffusion of pilocarpine through bovine cornea was measured using Edelhauser cells. In vivo, the rabbit aqueous humor concentration of pilocarpine and miosis were determined after application of the above formulations. In addition, intraocular pressure was measured. Since pilocarpine has little influence on intraocular pressure in healthy rabbits, the pressure had to be increased artificially. Three models were employed that are described in the literature, namely, the betamethasone model, the alpha-chymotrypsin model, and the water-loading model. Pilocarpine could be loaded onto nanoparticles by 15% but was rapidly released from the nanoparticles based on the bovine corneal experiment. Nanoparticles only enhanced the aqueous humor concentration at 30 min; this increase, however, led to a considerably extended period of miosis as well as a reduction in intraocular pressure. The duration of the action and the intensity of the response were different among the three models tested. According to the present results, the betamethasone model seems to represent the best correlation to the clinical situation.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-739X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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