The reactions of 10 flavonoids with 2,2-diphenyl-1-picrylhydrazyl radical (dpph(*)) carried out in alcohols always occur significantly faster than in acidified alcohols or in dioxane. These fast kinetics benefit from the contribution of the electron transfer from a flavonoid anion to a radical, a mechanism known as Sequential Proton-Loss Electron-Transfer (SPLET), which adds to the kinetics of single-step Hydrogen Atom Transfer (HAT)/Proton Coupled Electron Transfer (PCET) processes (see Acc. Chem. Res. 2007, 40 , 222.). The domination of SPLET over HAT/PCET in case of a flavonoid reacting with electron-deficient radicals such as peroxyls or dpph(*) in polar solvents explains the enhancement of antioxidant activity of 3-hydroxyflavone. It also elucidates the great acceleration in the reactions of dpph(*) with quercetin, morin, galangin, and 7,8-dihydroxyflavone. The analysis of structure-acidity and structure-activity relationships for 10 flavonoids clearly indicates that hydroxyl group at position 7 is the most acidic site. Thus, in polar solvents this group can participate in radical reaction via SPLET. In nonpolar solvents the most active site in quercetin (a flavonoid antioxidant commonly found in plants) is 3',4'-dihydroxyl moiety and HAT/PCET occurs. However, in ionization-supporting solvents an anion formed at position 7 is responsible for very fast kinetics of quercetin/dpph(*) reaction because both mechanisms participate: HAT (from catechol moiety in ring B) and SPLET (from ionized 7-hydroxyl in ring A). Because of conjugation of rings A, B, and C the final structure of the formed quercetin radical (or quercetin anion radical) is the same for the SPLET and HAT/PCET mechanisms.

Polimery do zastosowañ farmaceutycznych Streszczenie-Farmacja jest jedn¹ z wa¿niejszych dziedzin, w których znajduj¹ zastosowanie zwi¹zki wielkocz¹steczkowe. Polimery s¹ u¿ywane jako substancje farmakologiczne, oerodki krwiozastêpcze, ró¿ne substancje pomocnicze, a tak¿e s³u¿¹ do produkcji proleków wielkocz¹steczkowych, polimerowych systemów kontrolowanego uwalniania substancji leczniczych, systemów terapeutycznych, itp. Proleki wielkocz¹steczkowe, polimerowe systemy kontrolowanego uwalniania substancji leczniczych oraz systemy terapeutyczne cechuj¹ siê wyj¹tkow¹ farmakokinetyk¹, zdolnooeci¹ precyzyjnego transportu substancji leczniczej w organizmie oraz farmakologiczn¹ wydajnooeci¹. W niniejszej pracy opisano naturalne, modyfikowane i syntetyczne polimery stosowane w farmacji. S³owa kluczowe: polimery biomedyczne, proleki wielkocz¹steczkowe, systemy kontrolowanego uwalniania substancji leczniczej. POLYMERS FOR PHARMACEUTICAL APPLICATIONS Summary-The pharmacy is one of the most important areas in which the macromolecular compounds are applied. They are used as pharmacological substances, blood substitutes, various auxiliary materials or excipients as well as in the production of macromolecular prodrugs, polymeric drug delivery systems, therapeutic systems, etc. (Table 1 and 2). The prodrugs, polymeric drug delivery systems and therapeutic systems are characterized with unique pharmacokinetics, ability to distribute precisely the drugs in the organism as well as pharmacological efficiency. In this paper the natural, modified and synthetic polymers and examples of their applications were described.

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Solid C-methylcalix[4]resorcinarene solvated by acetonitrile and water (CAL-Me) and then modified by slow solvent evaporation (CAL-Me*) was studied using single-crystal and powder X-ray diffraction, FT-IR, and (13)C CP/MAS NMR. The CAL-Me solvate crystallizes in the monoclinic P2(1)/n space group with three CH(3)CN and two H(2)O molecules in the asymmetric part of the unit cell. The CAL-Me molecules adopt a typical crown conformation with all of the hydroxyl groups of the aryl rings oriented up and all of the methyl groups disposed down (the rccc isomeric form). The crystalline network is formed by resorcinarene, CH(3)CN, and H(2)O molecules and assembled by intermolecular hydrogen bonds and weak C-H...A or C-H...pi interactions. The desolvated CAL-Me* loses its crystalline character and becomes partly amorphous. It is devoid of CH(3)CN and deficient in water. However, the resorcinarene molecules still remain in the crown conformation supported by intramolecular hydrogen bonds, while intermolecular hydrogen bonds are considerably disintegrated. The work directs general attention to the problem of stability and polymorphism of resorcinarene solvates. It shows that the joint use of diffractometric and spectroscopic methods is advantageous in the structural studies of complex crystalline macromolecular systems. On the other hand, the solid-state IR and NMR spectroscopic analyses applied in tandem have been found highly beneficial to elucidate the disordered structure of poorly crystalline, desolvated resorcinarene.

Oxidative stability of high density polyethylene containing C-alkylcalix[4]pyrogallolarenes was studied by Differential Scanning Calorimetry. The kinetic parameters of non-isothermal oxidation indicate that pyrogallolarenes are effective antioxidants at temperatures above 150 °C.