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The reaction of diols with isocyanates, leading to mono-functional and di-functional prepolymers may be investigated using various characterization methods which show the overall conversion of isocyanate monomers. On the other hand, matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) polymer characterization can be employed to identify the monomer units, the end-group functionalities, molecular weight averages, and to determine the copolymer sequence. Herein, we focus on prepolymer synthesis using isophorone diisocyanate (IPDI), a widely used diisocyanate for prepolymers preparation, especially in waterborne polyurethane materials. Thus, the reaction between polyethylene glycol diol and IPDI was in-depth investigated by mass spectrometry to determine the influence of the reaction parameters on the prepolymer’s structure. The relative content of the different functional oligomer species at given reaction times was determined in the reaction mixture. More specifically, the offline analysis revealed the influence of reaction parameters such as reaction temperature, the concentration of reactants, and the amount of dibutyltin dilaurate catalyst. The established MALDI MS analysis involved measurements of samples, first, directly collected from the reaction mixture and secondly, following derivatization with methanol. The obtained results revealed the effects of reaction parameters on the functionalization reaction with isocyanates, allowing to achieve a better reaction control.

Poly(L-lactide) is capable of self-assembly into a nematic mesophase under the influence of temperature and mechanical stresses. Therefore, subsequent poly(L-lactide) films were obtained and characterized, showing nematic liquid crystal properties both before and after degradation. Herein, we present that, by introducing β-cyclodextrin into the polymer matrix, it is possible to obtain a chiral nematic mesophase during pressing, regardless of temperature and time. The obtained poly(L-lactide) films exhibiting liquid crystal properties were subjected to degradation tests and the influence of degradation on these properties was determined. Thermotropic phase behavior was investigated using polarized optical microscopy, X-ray diffraction, and differential scanning calorimetry. The degradation process demonstrated an influence on the liquid crystal properties of pressed polymer films. The colored planar texture of the chiral nematic mesophase, which was not observed prior to degradation in films without the addition of β-cyclodextrin, appeared after incubation in water as a result of the entrapment of degradation products in the polymer matrix. These unusual tailor-made properties, obtained in liquid crystals in (bio)degradable polymers using a simple method, demonstrate the potential for advanced photonic applications.

Cyclodextrins have previously been proven to be active in the catalysis of cyclic ester ring-opening reactions, hypothetically in a similar way to lipase-catalyzed reactions. However, the way they act remains unclear. Here, we focus on β-cyclodextrin’s involvement in the synthesis and characterization of β-cyclodextrin-oligocaprolactone (CDCL) products obtained via the organo-catalyzed ring-opening of ε-caprolactone. Previously, bulk or supercritical carbon dioxide polymerizations has led to inhomogeneous products. Our approach consists of solution polymerization (dimethyl sulfoxide and dimethylformamide) to obtain homogeneous CDCL derivatives with four monomer units on average. Oligomerization kinetics, performed by a matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) optimized method in tandem with 1H NMR, revealed that monomer conversion occurs in two stages: first, the monomer is rapidly attached to the secondary OH groups of β-cyclodextrin and, secondly, the monomer conversion is slower with attachment to the primary OH groups. MALDI MS was further employed for the measurement of the ring-opening kinetics to establish the influence of the solvents as well as the effect of organocatalysts (4-dimethylaminopyridine and (–)-sparteine). Additionally, the mass spectrometry structural evaluation was further enhanced by fragmentation studies which confirmed the attachment of oligoesters to the cyclodextrin and the cleavage of dimethylformamide amide bonds during the ring-opening process.

This paper highlights the efficiency of ultrasonication, as a clean and energy-saving method for the preparation of cellulose–iron oxide ferromagnetic composites in two steps. Hydroxyl-functionalized maghemite–goethite nanoparticles (MG) having a saturation magnetization of 56.9 emu g−1 at room temperature were first synthesized by a one-pot procedure involving ultrasonication of an aqueous alkaline Fe2+ salt solution. Organic–inorganic nanocomposites were obtained by a second ultrasonication step of an aqueous suspension of micronized cellulose and MG nanoparticles. The cumulative effect of ultrasonication and MG nano-projectiles was found to strongly decrease the degree of crystallinity of cellulose. The microstructural characterisation of the resulting composite evidenced its size polydispersity, with small nanoparticles uniformly attached on the surface of cellulose microfibrils. Vibrating sample magnetic measurement indicated a hysteresis curve specific to ferromagnetic materials and the appearance of a superparamagnetic phenomenon at low temperature (a blocking temperature of 62 K). Cellulose/iron oxide clusters with an average size around 7 nm and characterized by high decomposition temperatures (around 645 °C) were proven to be responsible for the observed superparamagnetic phenomenon. The superiority of the ultrasonication process versus a procedure involving simple mechanical stirring, in terms of composite yield, dispersion uniformity of MG nanoparticles and magnetic properties is discussed.

This paper aims to expand the range of matrix assisted laser desorption mass spectrometry analysis (MALDI MS) as a tool to establish the reaction kinetics for a particular case study: the synthesis of β-cyclodextrin-oligolactide (CDLA) derivatives through solution ring opening oligomerization (ROO) of d , l -lactide (LA) initiated by β-cyclodextrin (β-CD). Specifically, MALDI MS was used to estimate the molecular weight averages minute changes during the synthesis for a better understanding of the chemical process. The MALDI MS data was compared with 1H NMR for determining the DL-Lactide conversion rate and an excellent agreement level was established. The synthesis process was further studied by observing the effects of the reaction parameters with a special focus on the solvent influence. Thus, we observed that the ROO performed in dimethylformamide and N-methyl-2-pyrrolidone proceeds faster in comparison with dimethylsulfoxide due to an activation process in the LA ring opening reaction. The activation is produced by the amines resulted from the cleavage of the amide bonds in the presence of the β-CD or CDLA derivatives. The products of the degradation process were identified in the MS spectra and structurally confirmed through MS fragmentation experiments.

Erythromycin is a macrolide antibiotic prescribed for the topical treatment of acne. Pharmacologically, erythromycin has the disadvantage of being poorly soluble in water. This leads to formulation challenges in semisolid dosage forms. In recent years, many published studies have shown the ability of cyclodextrins to form complexes with drugs. These new complexes are characterized by much improved solubility and permeation compared to the „parent“ molecule. The aim of this study was to synthesize an inclusion complex of erythromycin and lactide-β-cyclodextrin for the formulation of semisolid bases and the development of innovative topical preparations with erythromycin. The erythromycin-lactide-βcyclodextrin complex was characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy. Semisolid formulations were pharmacologically evaluated by in vitro dissolution test and kinetic analysis of drug release by fitting to representative mathematical models. The results obtained showed a prolonged release of erythromycin from erythromycin-lactide-β-cyclodextrin formulations and a higher permeability coefficient of these formulations compared to the erythromycin-based release.

Barium titanate submicronic particles were prepared, for the first time, by a solid-state reaction route, where the classical ball grinding/mixing and drying steps were replaced by ultrasonication and microwave assisted processes, respectively, resulting in significant reduction in both drying duration and temperature of the thermal treatment. The structure of the prepared samples was analyzed by Fourier transform infrared spectroscopy and X-ray powder diffraction, while the morphology and particle size were followed by means of scanning electron microscopy and dynamic light scattering. Dielectric properties were evaluated in the frequency range of 106-10−2 Hz. The obtained results showed that the employed synthesis process leads to well-defined tetragonal phase BaTiO3 particles with relatively high tetragonality and average particle diameter of around 500 nm. The study on the dielectric behavior reveals that the obtained materials are appropriate for applications as passive electronic elements. The goal of the paper is to demonstrate the effectiveness of the ultrasonic treatment in the preparation of well-defined perovskite-like BaTiO3 particles by a solid-state process.

Biodegradable oligolactide derivatives based on α-, β- and γ-cyclodextrins (CDs) were synthesized by a green procedure in which CDs play the role of both the initiator and the catalyst. The synthetic procedure in which CDs and L-lactide (L-LA) are reacting in bulk at relatively high temperature of 110 °C was investigated considering the structural composition of the products. The obtained products were thoroughly characterized via mass spectrometry methods with soft ionization like matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI). Liquid chromatography (LC) separation with evaporative light scattering detection (ELSD) and NMR analysis were employed in order to elucidate the structural profiles of the obtained mixtures. The results clearly demonstrate that the cyclodextrins were tethered with more than one short oligolactate chain per CD molecule, predominantly at the methylene group, through ring opening of L-LA initiated by primary OH groups.

In this study, low molecular weight poly(&delta, valerolactone) (PVL) was synthesized through bulk-ring openings polymerization of &delta, valerolactone with boric acid (B(OH)3) as a catalyst and benzyl alcohol (BnOH) as an initiator. The resulting homopolymer was characterized with the aid of nuclear magnetic resonance (NMR) and mass spectrometry (MS) techniques to gain further understanding of its molecular structure. The electrospray ionization mass spectrometry (ESI-MS) spectra of poly(&delta, valerolactone) showed the presence of two types of homopolyester chains&mdash, one terminated by benzyl ester and hydroxyl end groups and one with carboxyl and hydroxyl end groups. Additionally, a small amount of cyclic PVL oligomers was identified. To confirm the structure of PVL oligomers obtained, fragmentation of sodium adducts of individual polyester molecules terminated by various end groups was explored in ESI-MSn by using collision induced dissociation (CID) techniques. The ESI-MSn analyses were conducted both in positive- and negative ion mode. The comparison of the fragmentation spectra obtained with proposed respective theoretical fragmentation pathways allowed the structure of the obtained oligomers to be established at the molecular level. Additionally, using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), it was proven that regardless of the degree of oligomerization, the resulting PVL samples were a mixture of two types of linear PVL oligomers differing in end groups and containing just a small amount of cyclic oligomers that tended to be not visible at higher molar masses.

The high interest in polymers from natural resources prompted us to investigate the use of enzymatically synthesized polyglobalide (PGL) in the preparation of polymer networks with potential applications as biomaterials for drug delivery devices. Polymer networks were obtained under mild conditions by photoinitiated thiol-ene coupling between PGL and a poly(ethylene glycol- co-thiomalate) (PEG-SH) copolymer obtained by polycondensation. The obtained polymer networks were thoroughly characterized by Raman spectroscopy, scanning electron microscopy, titration of thiol groups and elemental analysis. Our study took into consideration the synthesis parameters for the polymer networks, such as the total polymer concentration and the SH/C=C functionality molar ratio. Swelling in both THF and water was assessed, and the potential of the materials for drug delivery was determined. The scanning electron microscopy images showed that the prepared polymer networks may have different morphologies ranging from homogeneous polymer materials to macroporous structures. Additionally, the prepared materials were found to be suitable from a cytotoxicity point of view, enabling their application as biomaterials for drug delivery devices.

There is an increased need for polymer materials with low ecological impact and the use of renewable resources for polymer biosynthesis represents an attractive solution. In this context, the biosynthesis of polyhydroxyalkanoates (PHAs) represents perhaps one of the most solid responses offered by the researchers. This chapter covers the relevant and recent literature concerning the biosynthesis of PHAs and their physicochemical properties. The raw materials used in the fermentative production of PHAs are detailed. Also, the relevance of the specific properties of this class of polymers will be presented in respect to the biomedical field, with a special attention to the aspects related to the biodegradability, biocompatibility, and cytotoxicity of bacterial produced polymers. The methods for obtaining pharmacologically pure microbial PHAs and their custom modification methods are also reviewed. Moreover, the particular uses of the microbial synthesized PHAs for biomedical applications of PHAs and their importance for the biomedical field are described.

The paper focuses on the advances in the field of pain treatment by transdermal delivery of specific drugs. Starting from a short description of the skin barrier, the pharmacodynamics and pharmacokinetics including absorption, distribution, action mechanism, metabolism and toxicity, aspects related to the use of pain therapy drugs are further discussed. Most recent results on topical anesthetic agents as well as the methods proved to overcome the skin barrier and to provide efficient delivery of the drug are also discussed. The present review is proposing to summarize the recent literature on the pharmacotherapeutic principles of local anesthetics and non-steroidal anti-inflammatory drugs, generally used to alleviate pain but also the drugs as nanoformulations with potential applications in transdermal delivery. A special attention is given to efficient formulations meant for transdermal penetration enhancement of anesthetics where the drug is encapsulated into macrocyclic molecules (cyclodextrins, cyclodextrin derivatives), liposomes or polymer nanoparticles and hydrogels.

Co(II), Cd(II) and Rh(III) complexes with 2-(1H-1,2,4-triazol-3-yl)pyridine (Htzp) as ligand were synthesized and investigated. The neutral mononuclear complexes with a generic [M(tzp)n] structure have been prepared from Htzp and corresponding transition metals chlorides at 2:1 and 3:1, respectively molar ratios in H2O–EtOH. The resulted crystalline complexes were investigated through magnetic and molar conductivity measurements, elemental analysis, FT-IR, mass spectroscopy, thermal analysis, UV-Vis and P-XRD. The experiments indicate that Htzp acts as bidentate anionic ligand, [Co(tzp)2]·1.5H2O and [Cd(tzp)2] are in the tetragonal coordination, whereas six coordinate octahedral [Rh(tzp)3]·H2O complex undergoes a weak tetragonal distortion. In case of Co(II) complex, an interesting feature was revealed through fluorescence spectroscopy, as the fluorescent emission intensity of the free ligand is dependent on the Co(II) solution content. Through complexation, the fluorescence is gradually quenched according to the Co(II) aqueous solution content, which may recommend it as a method of detection of Co(II) presence in waste water.

In this review, we will summarize the particularities of each of the following barriers from the point of view of drugs passing across them; blood brain barrier, ocular barriers, skin and mucosal barriers. Also, for each biological barrier the most representative examples of polysaccharides and cyclodextrins nanoformulations are presented.

cited By 4; International audience; Novel drug-polymer conjugates were prepared by chemical immobilization of hydrazides on poly (N-vinyl pyrrolidone-alt-itaconic anhydride) support. Hydrazides with tuberculostatic activity were synthesized as derivatives of N-(p-nitrobenzoyl)-L-glutamine. Elemental and spectral analysis confirmed the chemical structure of the newly synthesized compounds and the evaluation of biological activity showed an increase of the tuberculostatic effect and a lower toxicity by chemically linking the hydrazides onto co-polymer. © 2013 Copyright Taylor and Francis Group, LLC.

End-capped and intramolecular azofunctional oligocaprolactones were characterized at molecular level by liquid chromatography electrospray ionization mass spectrometry (ESI MS) and NMR spectroscopy. The Disperse Red 19 (DR19) azofunctional oligomers, DC, were synthesized by ring-opening oligomerization of e-caprolactone (e-CL) initiated by the hydroxyl groups of DR19 azo dye. The reaction products consist of a minor fraction of end-capped azo functional oligocaprolactone (α-DC), that is, a single CL arm oligomer, and a major fraction of intramolecular azo functional oligocaprolactone (β-DC), that is, a two CL arms oligomer. The chromatographic separation was used to discriminate between α-DC and β-DC, and the results were confirmed by MS/MS performed on an ESI ion trap instrument. The results supported by accurate mass data obtained for product ions using an ESI quadrupole time of flight instrument demonstrate the qualitative discrimination at the molecular level between intramolecular and end-capped azofunctional oligoesters isomers through a relatively simple multistage mass spectrometry experiment. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

The surface properties of two conjugated main-chain polyrotaxanes, polyazomethine threaded on α-cyclodextrin (PA/α-CD), and 9,9-dioctylfluorene-bithiophene copolymer threaded on randomly methylated β-cyclodextrin (PF-BT/RM-βCD) were investigated and compared with PA and PF-BT non-rotaxane copolymers. Optical microscopy study of PF-BT/RM-βCD polyrotaxane showed the self-assembling of the lamellae into 3D large flat worm-like structures with an almost parallel distribution compared with disordered PF-BT reference copolymer. Lower values of the interfacial adhesion forces of polyrotaxane films, obtained by atomic force microscopy (AFM), were assigned both to the interactions of macrocycles with hydrophobic substrate and to their aggregation tendency.

Oligo(3-OH butyrate)-β-cyclodextrin esters (PHB-CD) were obtained through ring opening of β-butyrolactone (β-BL) in the presence of β-cyclodextrin (CD) and (-)-sparteine (SP) as nucleophilic activator. The resulted reaction mixture was first separated in two fractions and then investigated through a deep mass spectrometry (MS) study performed on a liquid chromatography-electrospray ionization-quadrupole time of flight (LC-ESI-QTOF) instrument. LC MS and tandem MS structural assignment of the reaction products was completed by NMR. The performed analysis revealed that poly(3-OH butyrate) homopolymers (PHB) are formed together with the PHB-CD products. Secondary reactions resulting in the formation of crotonates were also proved to occur. A comparison between MS and NMR results demonstrated that more than one PHB oligomer is attached to the CD in the PHB-CD product. The tandem MS fragmentation studies validated the proposed structure of CD derivatives. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5581-5592, 2010.

Cyclodextrins (CDs) were used in the present study for the ring-opening oligomerization (ROO) of l-lactide (LA) in order to synthesize biodegradable products with possible applications in pharmaceutical and medical fields. The practical importance of ROO reactions may reside in the possibility of synthesizing novel CD derivatives with high purity due to the dual role played by CDs, the role of the initiator through the hydroxylic groups, and the role of the catalyst by monomer inclusion in the CD cavity. The analyzed compounds were CDs modified with oligolactides obtained through ROO reactions of l-lactide in dimethylformamide. The resulting CD isomeric mixtures were investigated using classical characterization techniques such as gel permeation chromatography and nuclear magnetic resonance. Moreover, advanced mass spectrometry (MS) techniques were employed for the determination of the average number of monomer units attached to the cyclodextrin and the architecture of the derivatives (if the monomer units were attached as a single chain or as multiple chains). Thus, fragmentation studies effectuated on two different instruments (ESI Q-TOF and MALDI TOF) allowed us to correlate the size of the oligolactide chains attached to the CD with the observed fragmentation patterns.

The synthesis of novel azofunctional oligoesters through bulk ring opening of e-caprolactone and D,L-lactide (LA) at 100 and 130 °C, respectively, mediated by N-ethyl-N-(2-hydroxyethyl)-4-(4-nitrophenylazo)aniline (Disperse Red 1) (DR1) is described. The synthetic procedure allows "clean" products because no catalysts were used in the reaction. Moreover, DR1 moiety is showed for the first time to promote the ring opening of cyclic esters. The molecular structure of the obtained oligoesters was established by NMR spectroscopy, MALDI ToF MS and electrospray ionization mass spectrometry (ESI MS). ESI-MS/MS fragmentation experiments were used to demonstrate the nature of the chain end groups (hydroxyl and DR1). Intermolecular transesterification reactions were proved by mass spectrometry studies at least in the case of LA oligomerization.

2-(1H-1,2,4-Triazol-3-yl)pyridine was investigated as suitable ligand for the preparation of new Y(III), Sm(III), Eu(III), Gd(III) and Tb(III) complexes. Elemental analysis, mass spectrometry, thermal analysis, FT-IR and P-XRD methods were used to investigate their structural configuration. All the prepared complexes are highly luminescent, having an impressive visual emission under UV excitation. Fluorescence spectroscopy revealed in case of Sm(III), Eu(III) and Tb(III) complexes intense metal centered specific narrow band emissions from the f–f transitions within 4f orbitals, while in case of Gd(III) and Y(III) complexes intense wide band emissions were recorded most probable due the heavy atom effect over the excited intraligand states. The excitation peaks are conveniently located in UV-A region for all prepared complexes apart from Sm(III) complex where the excitation peak is located within the violet region of the spectrum. The remarkable luminescent properties might recommend these complexes for applications in optical devices, as photonic conversion media.

cited By 8; International audience; Chitosan gelatin particles could be the ideal candidate for intraocular drug delivery due to their desirable properties. Double crosslinking in double emulsion has been used as an original and reliable method for particles preparation and their morphology has been optimized considering the main synthesis parameters such as polymers ratio, crosslinker amount, stirring speed, tensioactive amount and ionic crosslinking time, respectively. The particles have been analyzed for their physical-chemical properties (swelling degree, drug loading and release capacity, surface characteristics, etc.), the enzymatic degradation properties along with in vivo ocular investigations (ocular biodistribution, in vivo drug release). In the present study cefuroxim was used as a model drug, which is generally used in the prophylaxis of postoperative endophthalmitis following cataract surgery after intraocular administration. The present study proved that the dimensions and the physical-chemical properties of the particles can be modulated (by varying the preparation parameters) to facilitate the administration, the biodistribution and the drug release in the specific segment of the eye. This experimental study demonstrated also the ability of fluorescent nanoparticles to penetrate ocular tissues close to the administration site (intravitreal injection) and especially their tendency to migrate deep in the retina at time intervals of 72 h. © 2015 Published by Elsevier B.V.

cited By 6; International audience; The aim of the article was the synthesis of novel L-phenylalanine derivatives with biological activity and their immobilization into polymeric particles. Thus, new formyl, acetyl and p-methoxy derivatives of L-phenylalanine with antitumor activity were synthesized by reaction with p-nitrobenzoyl chloride, followed by the reduction of nitro group and acylation of the new formed amino group. The chemical structures of the obtained aminoacid derivatives were determined by FT-IR, NMR, MS and elemental analyses. The compounds were encapsulated into chitosan- and gelatin-based submicronic capsules, prepared by double crosslinking (ionic and covalent) in a O/W/O double emulsion. The varying parameter polymer/ionic crosslinker molar ratio was seen to influence particle size, morphology, swelling degree, thermal properties, as well as their capacity to incorporate and release the new active principles. The in vivo acute toxicity and antitumoral effect of aminoacid derivatives in free form or encapsulated were evaluated on rats. Drug encapsulation into polymeric systems was proven to enhance antitumoral activity against implanted Guerin's carcinoma. © Springer Science+Business Media, LLC 2012.

International audience; Carboxyl modified gamma-cyclodextrin (CDSA) with a substitution degree of about 9.5 was prepared by the esterification of gamma-cyclodextrin (CD) with succinic anhydride in pyridine at 90 A degrees C. The chemical composition and the structure of CDSA were characterized by FT-IR, MALDI-TOF, X-ray diffraction pattern, potentiometric titration and TGA. Modified and native gamma-cyclodextrin associate with fullerene (C-60) in DMF-toluene mixture resulting 1:1 CDSA:C-60 and CD:C-60 inclusion complexes. Aqueous solutions of native cyclodextrin, carboxyl-modified cyclodextrin and their inclusion complexes with C-60 were used as microgel solvent (or swelling agent) for controlled release application. The release of solutions was induced by shear stress and demonstrated using rheo-optical set-up.