1,721,040 research outputs found
Design of semi-interpenetrating networks based on poly(ethyl-2-cyanoacrylate) and oligo(ethylene glycol) diglycidyl ether
Full text linkThe synthesis of semi-interpenetrating networks (SIPN) based on linear poly(ethyl 2- cyanoacrylate) (PECA) and oligo(ethylene glycol) diglycidyl ether (OEGDG) based polymer networks was motivated by the hypothesis that the brittleness of polycyanoacrylates may be overcome by incorporating them into a polymer network architecture. A sequential synthetic route was applied, in which first PECA was prepared by anionic polymerization. Subsequently, OEGDG was crosslinked with different anhydrides and curing catalysts to form networks with hydrolyzable ester bonds and interpenetrating PECA. These SIPNs showed a low water uptake compared to other polyether based networks. Some of the obtained materials were transparent and exhibited a great flexibility, which was maintained also after 24 h of immersion in water and subsequent drying. Such networks could be components of future stimuli-sensitive material systems
In vitro release studies from curcumin-loaded inulin-graft-vitamin E (INVITE) mucoadhesive micelles
Full text linkIn order to investigate the potential use of INVITE micelles for urinary tract infections, we tested the ability of INVITE micelles to entrap and release a hydrophobic model drug such as curcumin, known for its high antioxidant properties and we evaluated the micelles mucoadhesive properties. In particular, micelles from INVITE polymers, at different degrees of substitution in VITE (10, 20 and 40%), have been prepared by the direct dialysis method so obtaining three different micelle systems. The same systems have been further drug loaded with curcumin by using two different methods in order to evaluate the influence of loading methods on drug loading capacity. In vitro drug release studies and mucoadhesive properties in simulated physiological conditions were carried out aimed to verify whether this DDS could be good candidate for the treatment of UTI
Highly flexible poly(ethyl-2-cyanoacrylate) based materials obtained by incorporation of oligo(ethylene glycol)diglycidylether
Full text linkAmphiphilic inulin-d-α-tocopherol succinate (INVITE) bioconjugates for biomedical applications
No full textHerein is reported the synthesis and characterization of innovative inulin (INU)–vitamin E succinate (VITE) bioconjugates (INVITE). The obtained amphiphilic INU-based polymers, self-assembling in nanostructures, have been thought as new drug delivery systems (DDS) for the therapy of urinary tract infections (UTI).
The synthesis of INVITE bioconjugates was carried out in bulk, without isolation of intermediate products, to reduce the amount of solvents used in the purification steps and to prevent possible VITE oxidation during work up.
Six different INVITE conjugates (INVITE 1–6) have been synthesized by varying both the relative amount of VITE with respect to INU repetitive units and the reaction temperature.
Afterwards, the ability of the new conjugates to form micelle systems, by applying two different established methods for critical aggregation concentration (CAC) evaluation, has been verified. Both methods produced similar CAC values ranging from 2.5 × 10−3 mM to 2.4 × 10−2 mM in agreement with the different degrees of derivatization shown by the INVITE 1–6 conjugates.
The mean diameter of prepared INVITE micelles, resulted in the range 24–60 nm. The size of the obtained INVITE micelles did not change as measured at different time points up to 12 days, so confirming their stability upon storage
Inulin vinyl sulfone derivative cross-linked with bis-amino PEG: new materials for biomedical applications
Full text linkIn this work new hydrogels based oil biocompatible polymers such as inulin (INU) and O,O'-bis(2-aminoethyl)polyethyleneglycol (PEGBa) have been prepared and characterized. In particular, INU has been derivatized with divinyl sulfone (DV) this obtaining the INUDV derivative, a copolymer bearing double bonds highly reactive towards the conjugate addition by nucleophilic molecules. INUDV has been characterized by FT-IR, H-1-NMR and SEC analyses that have confirmed the success of the derivatization reaction. With the aim to obtain novel hydrogel systems. INUDV derivative has been cross-linked with PEGBa in phosphate buffer solution pH 7.4. The reaction has been carried out for 4 h at room temperature and various samples have been obtained by changing the amount of PEGBa. These hydrogels resulted to be homogeneous, transparent, colorless and odorless and they have been characterized by spectroscopic analysis, swelling, chemical and enzymatic degradation studies. Their cell compatibility has been evaluated in vitro by direct and indirect assays oil CaCo-2 cells
Efficient synthesis of pure monotosylated beta-cyclodextrin and its dimers
Full text link6-O-Monotosyl-β-cyclodextrin (mono-Ts-βCD) is one of the most important intermediates in the production of substituted βCD. So far, performing the monotosylation reaction and, in particular, the purification steps was challenging, relied on toxic solvents, and resulted in long and expensive procedures at, importantly, low yields. Here, the reaction of cyclodextrin with p-toluenesulfonyl chloride in aqueous environment is described to obtain a highly pure mono-Ts-βCD, for which a single-step purification with a cation exchange resin was applied. With this synthetic route and purification, yields could be increased from typically 98 mol %. From mono-Ts-βCD, β-cyclodextrin dimers linked by ethylenediamine (bis-Et-βCD) were successfully prepared (yield 93%, purity 96 mol %) in a one-step approach using an anion exchange resin to trap leaving groups that typically interfere in the reaction. This synthesis procedure with a direct collection of side-products may be a general strategy applicable for nucleophilic substitution of tosylated cyclodextrins
Synthesis, characterisation and properties of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide-graft-maleic anhydride precursors and their stimuli-responsive hydrogels
Full text linkA family of poly(amino acid)-maleic anhydride hydrogels were designed and synthesized. Water soluble
polymeric precursors were prepared by partially substituting the hydroxyl groups of the a,b-poly(N-2-
hydroxyethyl)-DL-aspartamide backbone with maleic anhydride, so as to provide double bonds for crosslinking
and carboxylic acid groups for pH and electric field responsiveness. Reaction conditions (reactive
mixture composition and catalysis) were systematically varied in order to obtain PHEA–MA precursors
with different and reliable graft-maleic anhydride levels. PHEA–MA precursors were characterised by
titration, Nuclear Magnetic Resonance (1H NMR), Fourier-Transformed Infrared Spectroscopy (FTIR)
and Size Exclusion Chromatography (SEC) for structural and molecular determination. Aqueous solutions
of selected PHEA–MA precursors were subjected to gamma-irradiation at different irradiation doses and
polymer to water concentrations in order to induce chemical crosslinking without the addition of crosslinking
agents. The yield of crosslinking reactions was evaluated by solubility tests as well as the effect of
ammonium persulphate, as assistant radical initiator for gamma crosslinking. Selected hydrogels were
tested through swelling measurements to prove their pH and electric field responsiveness. Structural features
of the different variants produced were related to the swelling behaviour
CONFRONTO DEI PROFILI DI DISSOLUZIONE IN VITRO DI SPECIALITA’ MEDICINALI E FARMACI EQUIVALENTI CONTENENTI MESALAZINA
Full text linkIn questo lavoro, sono stati utilizzati due diversi metodi di dissoluzione in-vitro al fine di verificare come le diverse specialità medicinali e farmaci generici considerati fossero in grado di rilasciare il farmaco in condizioni
temporali e di pH che simulano il passaggio delle compresse attraverso il tratto gastrointestinale; dallo stomaco al colon
Inulin as a multifaceted (active)substance and its chemical functionalization: From plant extraction to applications in pharmacy, cosmetics and food
No full textThis review is aimed at critically discussing a collection of research papers on Inulin (INU)in different scientific fields. The first part of this work gives an overview on the main characteristics of native INU, including production, applications in food or cosmetics industries, its benefits on human health as well as its main nutraceutical properties. A particular focus is dedicated to the extraction techniques and to the specific effects of INU on intestinal microbiota. Other than in food industry, the number of INU applications increases dramatically in the pharmaceutical field especially due to its simple chemical functionalization. Thus, aim of this review is also to give practical examples of chemical functionalization performed on INU also by including critical comments based on the direct experience of the Authors. With this aim, a full paragraph is dedicated to practical chemical experiences useful to reduce the efforts when establishing new experimental conditions. Moreover, the pharmaceutical technology is also taken in special consideration by underlining the aspects leading at the preparation of formulations based on INU. At the end of the review, a critical paragraph is intended to feed the scientists’ curiosity on this versatile polysaccharide
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