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ABSTRACT: Novel thermo-responsive hydrophilic microspheres were prepared by free radical polymerization of methacrylate bovine serum
albumin and N-isopropylacrylamide, as cross-linker and functional monomer, respectively. The incorporation of monomers in the network was
confirmed by infrared spectroscopy, while the network density and shape of hydrogels strictly depend on concentration of monomers
in the polymerization feed. The thermal analyses showed negative thermo-responsive behavior with pronounced water affinity
of microspheres at temperature lower than lower critical solution temperature (LCST). The in vitro release studies of drug-loaded
thermo-sensitive hydrogels were performed. Experimental data showed, for the copolymers with functional monomer/cross-linker
ratio ≤ 1, a predominant drug release in the collapsed state, while the copolymers with functional monomer/cross-linker ratio > 1
showed prominent drug release in the swollen state. Below the hydrogel LCST, drug release through the swollen polymeric networks
was observed, while a squeezing-out effect at temperature above the LCST was predominant.
Colloid and Polymer Science 04/2012; 287(7):779-787. · 2.33 Impact Factor
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ABSTRACT: The aim of this work is to design, prepare and characterize L-lysine based prodrugs capable of targeting 6-mercaptopurine to the colon, an anti-tumor and immunosuppressant drug, and 5-aminosalicylic acid (5-ASA), drug of choice for inflammatory bowel disease (IBD). More specifically, Nɛ-feruloyl-S-(6-purinyl)-L-lysine and Nɛ-acryloyl-S-(6-purinyl)-L-lysine were synthesized and then characterized by FT-IR, (1)H-NMR and GC/MS spectroscopies. The ability of feruloyl derivative in inhibiting lipid peroxidation in rat liver microsomal membranes, induced in vitro by tert-butyl hydroperoxide as source of free radicals, was evaluated. Moreover, Nɛ-acryloyl-S-(6-purinyl)-L-lysine, polymerizable prodrug, was used to microspheres realization for 5-ASA release. These lasts, obtained by emulsion inverse technique, were characterized by light scattering and scanning electron microscopy (SEM) analysis. The microspheres equilibrium swelling degree was evaluated and showed good swelling behaviour in simulating colonic fluids. Results confirm the possibility that the application range of L-lysine prodrug can be extended to the treatment of intestinal diseases whose conventional therapy envisages medications with serious side effects that, thanks to this new strategy, can be minimized in an optimal way.
International journal of pharmaceutics 09/2011; 420(2):290-6. · 2.96 Impact Factor
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ABSTRACT: Innovative niosomes made up of α,ω-hexadecyl-bis-(1-aza-18-crown-6) (bola), Span 80® and cholesterol (2:5:2 molar ratio) are proposed as suitable delivery systems for the administration of 5-fluorouracil (5-FU), an antitumoral compound largely used in the treatment of breast cancer. The bola-niosomes, after sonication procedure, showed mean sizes of ~200 nm and a loading capacity of ~40% with respect to the amount of 5-FU added during the preparation. Similar findings were achieved with PEG-coated bola-niosomes (bola, Span 80(R), cholesterol, DSPE-mPEG2000, 2:5:2:0.1 molar ratio respectively). 5-FU-loaded PEG-coated and uncoated bola-niosomes were tested on MCF-7 and T47D cells. Both bola-niosome formulations provided an increase in the cytotoxic effect with respect to the free drug. Confocal laser scanning microscopy studies were carried out to evaluate both the extent and the time-dependent bola-niosome-cell interaction. In vivo experiments on MCF-7 xenograft tumor SCID mice models showed a more effective antitumoral activity of the PEGylated niosomal 5-FU at a concentration ten times lower (8 mg/kg) than that of the free solution of the drug (80 mg/kg) after a treatment of 30 days.
Biomedical Microdevices 07/2009; 11(5):1115-25. · 3.03 Impact Factor
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ABSTRACT: Molecularly imprinted hydrogel nanospheres as devices for the controlled/sustained release of 5-fluororacil in biological fluids were synthesized employing one-pot precipitation technique as the polymerization method. Methacrylic acid as a functional monomer and ethylene glycole dimethacrylate as a cross-linker were used in polymeric feed. Morphological and hydrophilic properties were determined by scanning electron microscopy and water content measurement, and recognition and selectivity properties of spherical molecularly imprinted polymers were compared with the spherical non-imprinted polymers, both in organic (acetonitrile) and water media. Finally, in vitro release studies were performed in plasma simulating fluids.
Journal of Drug Targeting 12/2008; 17(1):72-7. · 2.70 Impact Factor
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ABSTRACT: Ferulic acid plays a chemopreventive role in cancer by inducing tumor cells apoptosis. As mitochondria play a key role in the induction of apoptosis in many cells types, here we investigate the mitochondrial permeability transition (MPT) and the release of cytochrome c induced by ferulic acid and its esters in rat testes mitochondria, in TM-3 and MLTC-1 cells. While ferulic acid, but not its esters, induced MPT and cytochrome c release in rat testes isolated mitochondria, in TM-3 cells we found that both ferulic acid and its esters induced cytochrome c release from mitochondria in a dose-dependent manner, suggesting a potential target of these compounds in the induction of cell apoptosis. The apoptosis induced by ferulic acid is therefore associated with the mitochondrial pathway involving cytochrome c release and caspase-3 activation.
Journal of Bioenergetics 03/2008; 40(1):19-26. · 2.81 Impact Factor
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ABSTRACT: A new sorbent for molecularly imprinted solid phase extraction (MISPE) was synthesized to extract and purify alpha-tocopherol (alpha-TP) from vegetable sources. Molecularly imprinted polymers (MIP) were synthesized using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking agent using a photo-polymerization procedure. A thermo-polymerization was also performed but no imprinting effect in the resulting materials was raised. The proposed MISPE protocol could overcome the drawback of traditional detection methods, which require pre-treatments of the samples. The possibility to obtain the selective recognition of alpha-TP from natural samples in aqueous mixtures represents one of the main advantages of our materials. Our procedure involves the direct HPLC injection of eluate without any treatment and above all the use of no toxic and biocompatible organic solvents. After the evaluation of the selectivity of the alpha-TP imprinted polymers, the performance of these materials as solid phase extraction (SPE) sorbents was investigated. Our MISPE-HPLC procedure has a high sensitivity, LOD and LOQ were 3.49x10(-7) and 1.16x10(-6) mol L(-1), respectively, as well as good precision (intraday precision below 3.3% and interday precisions below 6.5%) and recovery (60%). Thus, it can be successfully used for the purification of alpha-TP from bay leaves.
Analytica chimica acta 07/2007; 593(2):164-70. · 4.31 Impact Factor
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ABSTRACT: Unsaturated groups were introduced onto proteins in order to produce macromers that are able to undergo radical polymerisation. The initial protein used was bovine serum albumin (BSA) because it is biodegradable, biocompatible and easily available. Methacrylic groups were introduced onto BSA by reaction with methacrylic anhydride at controlled pH and temperature. The experimental conditions allowed the protein to be kept water-soluble. This water-solubility of the derivatised protein was essential when realising spherical polymeric microparticles via reverse phase suspension copolymerisation with N,N-dimethyacrylamide (DMAA). During the derivatisation, the insertion of the polymerisable groups affects only the sterically-available chemical functions of the native protein. Therefore, chain growth during the copolymerisation process involves only these groups, achieving a polymeric network around a structurally unmodified protein. The polymeric systems show high water affinity, ascribable to the hydrophilic properties of BSA. We have demonstrated that the achievement of the spherical form during the polymerisation depends on two factors: the degree of derivatisation of BSA, and the weight/weight (w/w) ratio of the protein to the comonomer. The beads obtained were characterised by Fourier transform IR spectrophotometry, particle size distribution analysis, and scanning electron microscopy (SEM). The samples investigated showed a remarkable affinity for water and a high swelling capacity. These properties depend upon the degree of derivatisation of BSA and on the percentage of DMAA in the copolymerisation mixture. In this paper we describe the starting materials and the experimental conditions used to prepare protein hydrogels by radical copolymerisation, which are intended for use in pharmaceutical and biomedical applications.
Colloid and Polymer Science 11/2004; 283(3):250-256. · 2.33 Impact Factor
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ABSTRACT: Spherical pH-sensitive microparticles have been prepared by reverse phase suspension polymerization technique. Starting polymer has been alpha,beta-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) partially derivatized with glycidylmethacrylate (GMA). PHEA-GMA copolymer (PHG) has been crosslinked in the presence of acrylic acid (AA) or methacrylic acid (MA) at various concentration. The obtained microparticles have been characterized by FT-IR spectrophotometry, particle size distribution analysis and scanning electron microscopy. In order to have information about water affinity of the prepared samples, swelling measurements have been carried out in aqueous media which simulate some biological fluids. The possibility to employ the prepared samples as pH-sensitive microparticles has been investigated by performing in vitro release studies. Experimental data have showed that the release rate from these microparticles depends on the environmental pH and the chemical structure of the drug.
Biomaterials 09/2004; 25(18):4333-43. · 7.40 Impact Factor
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ABSTRACT: Spherical molecularly imprinted polymers (SMIPs) have been prepared via a novel precipitation polymerization using sulfasalazine (prodrug used in the diseases of the colon) as template. The sulfasalazine was incorporated into SMIPs and into a spherical non-imprinted polymer (control), and then the release rate of the bioactive agent at different pH values was evaluated. Considerable differences in the release characteristics between imprinted and non-imprinted polymers have been observed. This opens the possibility of the development of drug release systems capable of modulating the release of a specific molecule. Photomicrography of spherical molecularly imprinted polymers (SMIPs).
Macromolecular Bioscience 02/2004; 4(1):22-6. · 3.89 Impact Factor
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ABSTRACT: Spherical polymeric microparticles have been prepared by a reverse-phase suspension polymerization technique. The starting
polymer was α,β-poly (N-2-hydroxyethyl)-dl-aspartamide (PHEA) partially functionalised with glycidylmethacrylate (GMA) in order to introduce reactive vinyl groups in
the side chain. The PHEA–GMA copolymer obtained (PHG) was cross-linked in a mixture of water/hexane–carbon tetrachloride in
the presence of sorbitan trioleate (Span 85) as surfactant and ammonium persulfate/N,N,N′,N′-tetramethylethylenediamine as initiator system. The reaction was also carried out in the presence of N,N′-dimethylacrylamide as comonomer or N,N′-ethylenebisacrylamide as a cross-linking agent. The beads obtained were characterized by Fourier transformIR spectrophotometry,
particle size distribution analysis and scanning electron microscopy, which revealed their microporous structure. X-ray diffractometry
and differential scanning calorimetry showed the amorphous state and the dependence of the glass-transition temperature on
the chemical structure of the samples prepared, respectively. Finally, in order to have information on the water affinity
of the networks obtained, swelling measurements were performed. The water regain values and the high rate of swelling demonstrate
a remarkable ability of the samples investigated to entrap water molecules. The dependence of aqueous swelling on the degree
of cross-linking and the chemical structure of the samples is also shown.
Colloid and Polymer Science 06/2001; 279(7):688-695. · 2.33 Impact Factor
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ABSTRACT: A new sorbent for molecularly imprinted solid-phase extraction (MISPE) to detect cholesterol (CHO) in food matrices able to work in an aqueous media was synthesized.The proposed MISPE protocol could overcome the limitations of traditional detection methods, which require pre-treatments of the samples, such as saponification, extraction with organic solvents, etc. The possibility to obtain selective recognition of CHO from food matrices in an aqueous mixture without hydrophobical non-specific interactions is the main advantage of these materials. Another important advantage of our procedure is the direct HPLC analysis of eluate without any treatment.In this study, three different MIPs, owing different hydrophilic characteristics were synthesized using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking agent. After the evaluation of the selectivity of the CHO imprinted polymers, the performance of these materials as Solid-Phase Extraction (SPE) sorbents was investigated. Good recoveries were obtained in the evaluation of the MISPE–HPLC procedure, which can be successfully used for the determination of CHO in Calabrian pecorino cheese.
Food Chemistry.
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ABSTRACT: Spherical polymeric microparticles have been prepared by a reverse phase suspension polymerization technique. The starting polymer was alpha,beta-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA), partially derivatized with glycidylmethacrylate (GMA). PHEA-GMA copolymer (PHG) was crosslinked in the presence of N,N'-dimethylacrylamide (DMAA) or N,N'-ethylenebisacrylamide (EBA). 5-fluorouracil was incorporated into PHG-DMAA or PHG-EBA beads both during and after the crosslinking process. Swelling studies revealed a high affinity toward aqueous medium, influenced by the presence of 5-fluorouracil. The in vitro release study showed that the release rate depends on the chemical structure of the beads and the procedure adopted to incorporate 5-fluorouracil into the microparticles.
Drug Delivery 9(2):97-104. · 1.46 Impact Factor
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ABSTRACT: The aim of this research is the preparation of acryloylated bovine serum albumin microspheres and the evaluation of their employment in drug delivery. The influence of preparation parameters on albumin microspheres and the chemicophysical properties of loaded drugs were investigated. In particular, we focused our attention on acylation albumin degree, amount of acryloylated albumin against comonomer in the polymerization step, and finally the release profile. We considered on the interaction drug-matrix, the fuctionalization degree of albumin, and the water affinity of matrix.
Drug Delivery 12(4):229-34. · 1.46 Impact Factor
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ABSTRACT: This article reports on the preparation of acryloylated bovine serum albumin microspheres and the evaluation of their employment in drug delivery areas. The influence of preparation parameters on albumin microspheres and the chemicophysical properties of loaded drugs were investigated. In particular, we focussed on acylation albumin degree and the amount of acryloylated albumin against comonomer in the polymerization step. Finally the release profile took into consideration the interaction drug-matrix, the fuctionalization degree of albumin, and the water affinity of matrix.
Drug Delivery 12(3):179-84. · 1.46 Impact Factor
