ABSTRACT
Hydrogels, based on polyacrylic acid and various macrodiisocyanates that contain polyethylene glycol, polypropylene glycol or polytetramethylene glycol in the main chain are synthesized. The obtained hydrogels are studied as possible polymer carriers of drug substances. Etophylin was applied as a model drug. It is exposed that the etophylin release rate from the hydrogel depends on the way of drug comprise in the polymer net, from its density from the chemical nature of the crosslinking agent and from the pH of the environment. The carried out studies let us to conclude that the obtained hydrogels are possible materials as drug carriers.
Subject(s)
Hydrogen-Ion Concentration , Purines/chemistry , Acrylates , Cross-Linking Reagents , Hydrogels , Isocyanates , Kinetics , Purines/administration & dosage , SolubilityABSTRACT
The calculations of the electronic structure and spectra of [Ru(NH3)5L]2+ (L = imidazole, histidine) and [Ru(NH3)5L]3+ (L = imidazole, N-imidazolate anion, 4-methylimidazole, 4-methyl-1N-imidazolate anion and 1N-bound histidine) complexes are performed in the framework of the CI method in the INDO/CNDO approximation. The MO diagram is obtained. The assignment of all transitions with energies of 4-5 eV is made and the nature of corresponding excited states is discussed. For the Ru(II) complexes, the lower energy observable transition is assigned to d-->pi* type, whereas the higher energy one is assigned to pi-->pi* type. In the spectra of the Ru(III) complexes with charged ligands both transitions are of pi-->d character, while in the case of uncharged ligands, the higher energy transition mostly incorporates pi-->pi* excitations.
