Іnvestigation of gel formation peculiarities and properties of hydrogels obtained by the structuring of acrylamide prepolymers

The paper represents the results of the investigation of the formation of a polymeric matrix of hydrogel due to the structuring of polyacrylamide using its reactive polymeric derivative – poly-N- (hydroxymethyl) acrylamide. Research determined zones of optimum conditions of synthesis and characterized hydrogel depending on pH of media, the ratio between the concentration of prepolymers, and time of synthesis. The investigation of the reaction mixture showed that the hydrogen index of the synthesis of hydrogels is one of the important factors, which in the design of the polymer framework of hydrogels allows regulating their colloidal chemical properties in a wide range.

Improvement of Peptide Affinity and Stability by Complexing to Cyclodextrin-Grafted Ammonium Chitosan

Cyclodextrin-grafted polymers are attractive biomaterials that could bring together the host–guest complexing capability of pristine cyclodextrin and the pharmaceutical features of the polymeric backbone. The present paper is aimed at characterizing the potential application of ammonium–chitosan grafted with 2-methyl-β-cyclodextrin (N+-rCh-MCD) as the functional macromolecular complexing agent for the oral administration of the neuropeptide dalargin (DAL). Specific NMR characterization procedures, along with UV and fluorescence techniques, as well as biological in vitro assessments have been performed. The results indicate that N+-rCh-MCD forms water-soluble complexes with DAL, with a prevalent involvement of Tyr or Phe over Leu and Ala residues. The association constant of DAL with the polymeric derivative is one order of magnitude higher than that with the pristine cyclodextrin (Ka: 2600 M−1 and 120 M−1, respectively). Additionally, N+-rCh-MCD shields DAL from enzymatic degradation in gastrointestinal in vitro models with a three-fold time delay, suggesting a future pharmaceutical exploitation of the polymeric derivative. Therefore, the greater affinity of N+-rCh-MCD for DAL and its protective effect against enzymatic hydrolysis can be attributed to the synergistic cooperation between cyclodextrin and the polymer, which is realized only when the former is covalently linked to the latter.

Synthesis by oxidative polymerization of optically active, regioregular polythiophene from quinquethiophene monomer bearing chiral and n-dodecyl groups as substituents

The synthesis and characterization of an optically active quinquethiophene monomer 3,3””-didodecyl-4’,3”’-di[(S)-(+)-2-methylbutyl]- 2,2’:5’,2”:5”,2”’:5”’,2””-quinquethiophene [(S)-(+)-DDDMBQT], bearing at the C-β positions of thiophene rings both linear C12 alkyl chain and chiral, enantiomerically pure, alkyl group is described. The polymerization of [(S)-(+)-DDDMBQT] by oxidative mechanism has been optimized in terms of yield of soluble polymer with high molecular weight.The obtained polymeric derivative displays enhanced conjugation extension with respect to similar poly(3-alkylthiophene)s reported in the literature and optical activity in the spectral region related to the chromophore absorptions when in the microaggregate state, indicative of the presence of supramolecular chiral conformations.