Using water-in-oil emulsions with a high volume share of aqueous (droplet) phase as precursors (High Internal Phase Emulsions; HIPEs), highly porous polymers (polyHIPEs) were prepared from glycidyl methacrylate (GMA) and ethylhexyl acrylate (EHA), their morphology investigated and mechanical and chromatographic characteristics evaluated. All polyHIPE monoliths had open cellular porous morphology with primary pores (cavities) between 4,8 %m and 26,2 %m and secondary level of interconnecting pores. Introduction of EHA into the oil phase and consequently into the polymer matrix of polyHIPEs had a significant effect on the mechanical properties; both tensile strength and elasticity were increased. On the other hand, chromatographic properties, such as protein binding capacity and back pressure, did not dramatically change.
COBISS.SI-ID: 17661718
This study describes the biotransformation of cytostatic and immunosuppressive pharmaceutical methotrexate. Its susceptibility to microbiological breakdown was studied in a batch biotransformation system, in presence or absence of carbon source and at two activated sludge concentrations. The primary focus of the present study are methotrexate biotransformation products, which were tentatively identified by the ultra-high performance liquid chromatography-quadrupole-Orbitrap-MS. Data-dependent experiments, combining full-scan MS data with product ion spectra were acquired, in order to identify the molecular ions of methotrexate transformation products, to propose the molecular formulae and to elucidate their chemical structures. Among the identified transformation products 2,4-diamino-N10-methyl-pteroic acid is most abundant and persistent. Other biotransformation reactions involve demethylation, oxidative cleavage of amine, cleavage of C-N bond, aldehyde to carboxylate transformation and hydroxylation. Finally, a breakdown pathway is proposed, which shows that most of methotrexate breakdown products retain the diaminopteridine structural segment. In total we propose nine transformation products, among them eight are described as methotrexate transformation products for the first time.
COBISS.SI-ID: 27698727
Prolonged vinblastine (VLB) infusion and irradiation (IR) lead to favourable results in certain tumours types, however the underlying biological mechanisms of interaction are not well known. The aim of our study was to evaluate the dose and time dependent interactions between split-dose VLB treatment (mimicking prolonged infusion) and IR of sarcoma SA-1 tumours in A/J mice. Positive antitumor effect was obtained when tumours were irradiated immediately after the first (0 h) or second (4 h) injection of VLB treatment, despite the lower amount of VLB in the tumours as well as decreased number of cells in IR sensitive G2M phase at these times points as opposed to the second half of VLB split-dose scheduling. Preferential binding of VLB to microtubules (with consequent lack of available VLB to bind to DNA where it acts as radioprotector) and the absence of radiobiologically relevant hypoxia are presumably leading to the observed therapeutic benefit of applying IR at the beginning of the prolonged VLB infusion.
COBISS.SI-ID: 1730427