- Xanthines, optionally incorporated in liposomes, for promoting skin or hair pigmentation
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A method of treating skin or hair for promoting pigmentation wherein a xanthine component, in an amount effective to promote pigmentation, is incorporated in liposomes or hydrated lipidic lamellar phases.
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- Effects of Alkyl Substitutions of Xanthine Skeleton on Bronchodilation
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Structure-activity relationships in a series of 1,3,7-trialkyl-xanthine were studied with guinea pigs.Relaxant actions in the tracheal muscle were increased with alkyl chain length at the 1- and 3-positions of the xanthine skeleton, but decreased by alkylation at the 7-position.Positive chronotropic actions in the right atrium were potentiated with 3-alkyl chain length but tended to decrease with 1-alkylation and diminish by 7-substitution.Consequently, while the 1- and 3-substitutions were equally important for the tracheal smooth muscle relaxation, the substitution at the 1-position was more important than the 3-substitution for bronchoselectivity.The 7-alkylation may be significant to cancel heart stimulation.There were good correlations between the smooth muscle relexant action and the cyclic AMP-PDE inhibitory activity in 3-substituents and the affinity for adenosine (A1)receptors in 1-,3-, and 7-substituents.This suggests that not only the cyclic AMP-PDE inhibitory activity but also the adenosine antagonistic activity is important in the bronchodilatory effects of alkylxanthines.Among these xanthine derivatives, 1-butyl-3-propylxanthine and its 7-methylated derivative showed high bronchoselectivity in the in vitro and in vivo experiments compared to theophylline and enprofylline and may be new candidates for bronchodilator.
- Sakai, Ryosuke,Konno, Kayo,Yamamoto, Yasunori,Sanae, Fujiko,Takagi, Kenzo,et al.
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p. 4039 - 4044
(2007/10/02)
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- Structure-activity relationships in a series of xanthine derivatives with antibronchoconstrictory and bronchodilatory activities
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Thirty-one 1,3,7,8-substituted xanthine derivatives have been synthesized and evaluated for bronchodilator and anti-bronchoconstrictory activities in in vitro tracheal relaxation and in vivo bronchospasm inhibition models. Activity tests have been complemented with phosphodiesterase inhibition and toxicological data. Structure-activity relationships are discussed. Compound 21 (1,3-diisobutyl-8-methylxanthine) has been selected for further pharmacological development because of its good activity profile and favourable therapeutic index, which is 14- and 38-fold greater than that of theophylline and IBMX, respectively.
- Merlos,Gomez,Vericat,Bartroli,Garcia-Rafanell,Forn
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p. 653 - 658
(2007/10/02)
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