New Hydrophilic Matrix Tablets for the Controlled Released of Chlorzoxazone.

The modified release of active substances such as chlorzoxazone from matrix tablets, based on Kollidon®SR and chitosan, depends both on the drug solubility in the dissolution medium and on the matrix composition. The aim of this study is to obtain some new oral matrix tablet formulations, based on Kollidon®SR and chitosan, in order to optimize the low-dose oral bioavailability of chlorzoxazone, a non-steroidal anti-inflammatory drug of class II Biopharmaceutical Classification System. Nine types of chlorzoxazone matrix tablets were obtained using the direct compression method by varying the components ratio as 1:1, 1:2, and 1:3 chlorzoxazone/excipients, 20-40 w/w % Kollidon®SR, 3-7 w/w % chitosan while the auxiliary substances: Aerosil® 1 w/w %, magnesium stearate 0.5 w/w % and Avicel® up to 100 w/w % were kept in constant concentrations. Pharmaco-technical characterization of the tablets included the analysis of flowability and compressibility properties (flow time, friction coefficient, angle of repose, Hausner ratio, and Carr index), and pharmaco-chemical characteristics (such as mass and dose uniformity, thickness, diameter, mechanical strength, friability, softening degree, and in vitro release profiles). Based on the obtained results, only three matrix tablet formulations (F1b, F2b, and F3b, containing 30 w/w % KOL and 5 w/w % CHT, were selected and further tested. These formulations were studied in detail by Fourier-transform infrared spectrometry, X-ray diffraction, thermogravimetry, and differential scanning calorimetry. The three formulations were comparatively studied regarding the release kinetics of active substances using in vitro release testing. The results were analyzed by fitting into four representative mathematical models for the modified-release oral formulations. In vitro kinetic study revealed a complex mechanism of release occurring in two steps of drug release, the first step (0-2 h) and the second (2-36 h). Two factors were calculated to assess the release profile of chlorzoxazone: f1-the similarity factor, and f2-the factor difference. The results have shown that both Kollidon®SR and chitosan may be used as matrix-forming agents when combined with chlorzoxazone. The three formulations showed optima pharmaco-technical properties and in vitro kinetic behavior; therefore, they have tremendous potential to be used in oral pharmaceutical products for the controlled delivery of chlorzoxazone. In vitro dissolution tests revealed a faster drug release for the F2b sample.

Temperature-Controlled Chain Dynamics in Polyimide Doped with CoCl2 Probed Using Dynamic Mechanical Analysis.

Cobalt(II) chloride (CoCl2) being in the vicinity of polyimide chains entails modifications in terms of the molecular dynamics, which are mainly governed by the possible presence of amic acid residual groups, by the transition-metal-type characteristics of cobalt and by the CoCl2 content. Polyimide was synthesized using poly(amic acid) according to the reaction of 2,2'-bis(3,4-dicarboxylphenyl)hexafluoropropane dianhydride (6FDA) with 3,3'-dimethyl-4,4'-diaminodiphenylmethane (MMDA) in N,N-dimethylacetamide. CoCl2 was added before the thermal imidization of the poly(amic acid). An experimental approach was designed to establish the interaction between the polyimide and CoCl2 and whether the interaction depends on the quantity of the salt. Evidence for the existence of residual amic acid groups was obtained using second derivative Fourier Transform Infrared Spectroscopy (FTIR) and with the help of 2D correlation spectroscopy (2D-COS). Moreover, FTIR, along with X-ray photoelectron spectroscopy (XPS), revealed the interaction between the polymer and CoCl2, primarily in the form of Co(II)-N coordinated bonds. Nevertheless, the coordination of cobalt with suitable atoms from the amic acid groups is not precluded. The results of dynamic mechanical analysis (DMA) featured a specific relaxation assigned to the presence of CoCl2 in the polymeric film and demonstrated that its (non)reinforcing effect depends on its content in the polyimide.

Development of Solid Lipid Nanoparticles for Controlled Amiodarone Delivery.

In various drug delivery systems, solid lipid nanoparticles are dominantly lipid-based nanocarriers. Amiodarone hydrochloride is an antiarrhythmic agent used to treat severe rhythm disturbances. It has variable and hard-to-predict absorption in the gastrointestinal tract because of its low solubility and high permeability. The aims of this study were to improve its solubility by encapsulating amiodarone into solid lipid nanoparticles using two excipients-Compritol® 888 ATO (pellets) (C888) as a lipid matrix and Transcutol® (T) as a surfactant. Six types of amiodarone-loaded solid lipid nanoparticles (AMD-SLNs) were obtained using a hot homogenization technique followed by ultrasonication with varying sonication parameters. AMD-SLNs were characterized by their size distribution, polydispersity index, zeta potential, entrapment efficiency, and drug loading. Based on the initial evaluation of the entrapment efficiency, only three solid lipid nanoparticle formulations (P1, P3, and P5) were further tested. They were evaluated through scanning electron microscopy, Fourier-transform infrared spectrometry, near-infrared spectrometry, thermogravimetry, differential scanning calorimetry, and in vitro dissolution tests. The P5 formulation showed optimum pharmaco-technical properties, and it had the greatest potential to be used in oral pharmaceutical products for the controlled delivery of amiodarone.

Gelatin Reinforced with CNCs as Nanocomposite Matrix for Trichoderma harzianum KUEN 1585 Spores in Seed Coatings.

Increasing interest on sustainable agriculture has led to the development of new materials which can be used as seed coating agents. In this study, a new material was developed based on gelatin film reinforced with cellulose nanocrystals (CNC) which was further used as nanocomposite matrix for Trichoderma harzianum KUEN 1585 spores. The nanocomposite films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM), showing the formation of new hydrogen bonds between the components with a good compatibility between them. Measurements of water contact angles and tests of water vapor sorption and swelling degree revealed an improvement in the water vapor absorption properties of the films as a result of their reinforcement with CNC. Furthermore, by adding the Trichoderma harzianum KUEN 1585 spp. in the seed coating material, the germination percentage, speed of germination and roots length of the corn seeds improved. The polymeric coating did not inhibit the growth of T. harzianum KUEN 1585, with this material being a good candidate in modern agriculture.

Effect of Cellulose Nanocrystals Nanofiller on the Structure and Sorption Properties of Carboxymethyl Cellulose-Glycerol-Cellulose Nanocrystals Nanocomposite Systems.

Biobased materials present a great interest due to their properties and biodegradability. Cellulose nanocrystals (CNC) nanofiller, in various amounts, was incorporated into a carboxymethyl cellulose (CMC)-glycerol (G) matrix in order to obtain nanocomposite systems with improved properties. The effect of the nanofiller on the structural features was investigated by Fourier transform infrared (FT-IR) spectroscopy, principal component analysis (PCA), two-dimensional correlation spectroscopy (2D-COS), and X-ray diffraction, while the sorption properties were evaluated by water vapor isotherms using the gravimetric method coupled with infrared spectroscopy. We observed the presence of the interactions taking place between the CMC-G and CNC involving the hydroxyl and carboxylate groups, which decreased the number of water sorption sites. Following this, the moisture content in the nanocomposite films decreased with the increase in the amount of CNC. Moreover, the bands associated to water molecules presented different wavenumber values separated for CMC-G and CNC components.

Synthesis and characterization of κ-carrageenan bio-nanocomposite films reinforced with bentonite nanoclay.

Due to ecological reason, in the last period there is an increased interest for changing the synthetic based materials with biodegradable ones. In this study, we prepared bio-nanocomposite formulations based on κ-Carrageenan (κ) and bentonite nanoclay (BT) with different component concentrations (0% BT, 5% BT, 10% BT and 15% BT respectively) and investigated their structural features, with focus on the interactions, sorption properties, and how the combination between them influences these properties. By infrared spectroscopy was identified that in the blending process hydrogen bonds and/or electrostatic interactions may have occurred between BT and κ. The water uptake and water sorption ability decreased with the increasing of the BT content in the formulations, from about 12% for κ to 9% for κ-BT 85:15% and from about 128% for κ to 121% for κ-BT 85:15%, respectively. Water adsorption can significantly decrease if the reinforcement materials are homogenusly dispersed in the matrix. The increase of the BT content induced also a decrease of the water contact angle at the surface from 76o for κ to 27o for κ-BT 85:15%.

Structural and sorption properties of bio-nanocomposite films based on κ-carrageenan and cellulose nanocrystals.

There is an increased interest on changing the synthetic based materials to biodegradable ones, especially with natural polymers, polysaccharides or proteins. In this research we prepared bio-nanocomposite formulations with different component concentrations and investigated their structural features, with focus on the interactions, sorption properties, and how the combination between them influences these properties. By infrared spectroscopy, principal component analysis (PCA) and two-dimensional correlation spectroscopy (2DCOS) was identified that in the blending process are involved the -SO4 and C(4)-O-S groups of ß-d-galactose, CO groups, (O=S=O) of carrageenan and -OH and CO groups from CNCs. The water uptake and water sorption properties decrease with increasing the CNCs content in the formulations from about 15% for κ to 10% for κC15 and from about 128% for κ to 115% for κC15, respectively. The increase of the CNCs content induced an increase of the water contact angle from 47° for κ to 90° for κC15, indicating once again the involvement of the free hydroxyl groups in the hydrogen bonded interactions.

Structural and morphological evaluation of CNC reinforced PVA/Starch biodegradable films.

Nanocomposite films containing cellulose nanocrystals (CNC), as the reinforcing phase, and poly(vinyl alcohol) (PVA)/starch (S) blend, as the matrix, were prepared by solution casting technique. For the preparation, 5, 10, 15 wt% CNC suspension were incorporated in blends containing 90 wt% PVA/10 wt% S, 75 wt% PVA/25 wt% S and 50 wt% PVA/50 wt% S. Structural evaluation was done by Fourier transform infrared spectrometry and X-ray diffraction, and the morphological aspects by atomic force microscopy. Infrared spectroscopy evidenced the presence of H-bond interactions between the PVA and S and between PVA/S blend and CNC, and also variation in the conformational rearrangement, while the X-ray diffraction showed that the crystallite size and the degree of crystallinity were strongly affected by blending of PVA with S and also by the incorporation of CNC in the nanocomposite films. The surface roughness of studied samples increased with the increasing of S and filler content.

Structural changes of wood during hydro-thermal and thermal treatments evaluated through NIR spectroscopy and principal component analysis.

Spruce wood samples were subjected to different conditions of thermal and hydro-thermal treatment by varying the temperature, relative humidity and period of exposure. The obtained treated samples were evaluated using near infrared spectroscopy (NIR), principal component analysis (PCA) and hierarchical cluster analysis (HCA) in order to evidence the structural changes which may occur during the applied treatment conditions. Following this, modification in all wood components were observed, modifications which were dependent on the temperature, amount of relative humidity and also the treatment time. Therefore, higher variations were evidenced for samples treated at higher temperatures and for longer periods. At the same time, the increase in the amount of water vapours in the medium induced a reduced rate of side chains and condensation reactions occurring in the wood structure. Further, by PCA and HCA was possible to discriminate the modifications in the wood samples according to treatment time and amount of relative humidity.

Structure and sorption properties of CNC reinforced PVA films.

Bio-nanocomposite films based on cellulose nanocrystals reinforced poly(vinyl alcohol) were obtained by solvent casting method. To assess the structural features of the films, different spectral techniques (FTIR, 2D COS and XRD) have been used. Infrared and 2D correlation spectroscopy evidenced the presence of H-bond interactions between the PVA and CNC, and the variation in the conformational rearrangements, while XRD showed that the crystallite size and the crystallinity degree were affected by the incorporation of CNC. At low content of CNC in the PVA matrix, the crystallinity degree decreased to 29.9%, while at higher CNC content increased to 80.6%, comparing to PVA (35.4%). To evaluate the interaction with water, contact angle measurement, water sorption and NIR spectroscopy were used, respectively. The increase of the CNC content induced a reduction in water sorption ability from 93% for PVA to 75% for PVA/CNC films, indicating the involvement of the hydroxyl groups in new hydrogen bonded interactions. By analyzing the variation of the NIR bands from 1930, 1902 and 1985nm, was observed that the water molecules interact with the polymer matrix through moderate hydrogen bond before diffusing into the free volume of the matrix and form stronger hydrogen bonds.

Out-of-water constitutional self-organization of chitosan-cinnamaldehyde dynagels.

An investigation of the constitutional adaptive gelation process of chitosan/cinnamaldehyde (C/Cy) dynagels is reported. These gels generate timely variant macroscopic organization across extended scales. In the first stage, imine-bond formation takes place "in-water" and generates low-ordered hydrogels. The progressive formation of imine bonds further induces "out-of-water" increased reactivity within interdigitated hydrophobic self-assembled layers of Cy, with a protecting environmental effect against hydrolysis and that leads to the stabilization of the imine bonds. The hydrophobic swelling due to Cy layers at the interfaces reaches a critical step when lamellar self-organized hybrids are generated (24 hours). This induces an important restructuration of the hydrogels on the micrometric scale, thus resulting in the formation of highly ordered microporous xerogel morphologies of high potential interest for chemical separations, drug delivery, and sensors.

Validation of spectrophotometric method for Se(IV) determination: analytical applications.

As selenium is an important part of the antioxidant enzymes and also because there are several studies suggesting a possible link between cancer and selenium deficiency, this paper presents a spectrophotometric method for the assay of Se(IV), using N,N-diethyl-p-phenylenediamine monohydrochloride as reagent. The proposed method is based on the reaction between the selenium and potassium iodide in low acidic medium, when iodine is released. This last product will further oxidise the new reagent. The final obtained product is strongly coloured in red and has an absorption maximum at 552 nm and molar extinction coefficient (ε) of 6.1 × 10(4) L mol(-1) cm(-1). The optimum working conditions were established, and the developed method was validated, being characterised by a good linearity (in the range of 0.5-3.0 µg/mL), a limit of detection (0.0573 µg/mL) and a limit of quantification (0.1737 µg/mL). At the same time, the repeatability, the precision of the method and the accuracy were established. The proposed and validated method was applied with good results for the determination of Se(IV) in spring and bottled water from Iasi and also in pharmaceutical and cosmetic products.

A near infrared spectroscopic study of the structural modifications of lime (Tilia cordata Mill.) wood during hydro-thermal treatment.

The modifications and/or degradation of lime (Tillia cordata) wood components during wood heat treatment under low temperature at about 140°C and 10% percentage of relative humidity were evaluated. The aim of this study was to obtain results by simple NIR coupled with second derivative, principal component analysis and two dimensional correlation spectroscopy in order to better understand how these techniques are able to evaluate structural differences resulted under hydro-thermal treatment of the wood over a period of 504h. The NIR spectra of treated samples were compared with the reference one. Due to the broad bands in the NIR spectra, the assignment and modifications occurring during treatment is difficult, therefore the second derivative principal component analysis were applied. Principal component analysis by first two components was able to differentiate the samples series, PC1 being considered as the time axis, and PC2 as the axis representing the structural modification of wood components. 2D NIR correlation spectroscopy was able to estimate the sequential order of the groups variations under the hydro-thermal treatment time as external perturbation, indicating as first moment changes the OH and CO groups from carbohydrates and lignin, followed by CarH, CH and CH2 groups from lignin, cellulose and hemicelluloses.

Chitosan as matrix for bio-polymer dispersed liquid crystal systems.

The obtaining of bio-polymer dispersed liquid crystal (bio-PDLC) systems based on a chitosan polymer matrix is reported here for the first time. The new PDLC composites have been obtained by encapsulation of 4-cyano-4'-pentylbiphenyl (5CB) as low molecular weight liquid crystal into chitosan, and they have been characterized by polarized optical microscopy, differential scanning calorimetry, electron and transmission scanning microscopy, Raman and fluorescence spectroscopy. Submicrometric liquid crystalline droplets with uniform size distribution and density have been obtained for low liquid crystal content into the PDLCs. The droplets have a radial configuration being anchored into chitosan matrix by an interface ordering coupling phenomenon.

Effect of the lignin type on the morphology and thermal properties of the xanthan/lignin hydrogels.

This paper reports the morphological and thermal characterization of xanthan/lignin hydrogels. It has been emphasized the effect of the lignin type on the hydrogel properties. The hydrogels described here were obtained by chemical crosslinking, in the presence of epichlorohydrine as a cross-linker agent. The obtained materials were analyzed by AFM, TG/DTG, DSC, and FT-IR spectroscopy. It has been established that hydrogels have a porous morphology. The lignin type influences the hydrogel morphology which is either fibrilar as in case of hydrogel containing aspen wood lignin (which has the highest content of COOH groups and lowest content of phenolic OH groups) or smooth surface for other hydrogels. The specific intermolecular interactions are stronger in the case of 70 xanthan (X)/30 aspen wood lignin (AWL) hydrogel. The thermal properties of the hydrogels also depend on lignin type, the lowest thermal stability being found for the hydrogel containing lignin with the highest content of functional groups (AWL).

Multivariate statistical analysis of mid-infrared spectra for a G1 allyl-terminated carbosilane dendrimer.

The FTIR spectra were measured for G1 allyl terminated carbosilane dendrimer over a temperature range of 25-200°C to explore the temperature-dependent changes. The dendrimer spectra exhibited complicated patterns and thus were analyzed by both the exploratory principal component analysis (PCA) and two-dimensional (2D) correlation spectroscopy. Boltzmann fitting and score plots of PCA evidenced the phase transition temperature to be about 172°C. Frequency variables, which strongly contributed to each principal component highlighted in their loadings plot, were linked to the frequencies assigned to vibrations of the CH(2) and CH(3) groups, as well as to vibrations of the SiCH groups. 2D correlation spectroscopy discerned all the sequences of group motion of dendrimer, indicating that during the heating process a reorganization of core structure takes place, followed by a conformational rearrangement of the terminal units.

Two-dimensional infrared correlation spectroscopic studies of polymer blends--specific interactions in polyethylene adipate/cholesteryl palmitate blends.

Generalized two-dimensional infrared (2D IR) correlation spectroscopy has been applied to the study of the conformational changes and specific interactions in blends of polyethylene adipate (PEA) and cholesteryl palmitate (CP). IR spectra of CP, PEA, and their blends of different compositions: 10/90, 16/84, 32/68, 64/36, and 80/20 have been recorded. In order to apply 2D IR correlation analysis, the samples are divided into two sets: set A with high PEA content 0/100, 10/90, 16/84, 32/68 CP/PEA and set B with high CP content 64/36, 80/20 and 100/0 CP/PEA. The 2D IR synchronous correlation analysis separates the bands of PEA from those of CP. The cross-peaks in 2D IR asynchronous correlation analysis are indicative of the specific interaction or the conformational change in the blends. The bands of CO, OH and C-O vibrations of PEA, and CH(3) and C-O vibrations of CP that are very sensitive to the intermolecular hydrogen bonding effect and consequently the partial miscibility of components, have been assigned by 2D correlation analysis.

Structural analysis of photodegraded lime wood by means of FT-IR and 2D IR correlation spectroscopy.

In this study the weathering behavior of lime wood (Tillia cordata Mill.) has been examined using FT-IR and 2D IR correlation spectroscopy, which evidenced chemical changes induced by exposure to weathering conditions. It was showed that lignin is most sensitive component to the photodegradation processes as indicated by considerable decreases in the intensities of the characteristic aromatic lignin band at 1505cm(-1) and other associated bands. By 2D correlation spectroscopy has been demonstrated that the moment of CO from carboxyl and acetyl groups in hemicelluloses is changing first, followed by the CC of aromatic skeletal, CO in non-conjugated ketones, carboxyl groups and lactones, absorbed O-H and conjugated C-O groups in quinones. The carbonyl formation corresponded well with lignin degradation, indicating a close relationship between them. Comparing the rate of carbonyl formation and lignin decay clearly showed that the former is remarkably higher than the latter, indicating the formation of carbonyl bands at 1738cm(-1) probably resulted from not only lignin oxidation but also from reactions occurring in other components of the wood. Quinine formation is combined with the decay of aromatic structures and the formation of conjugated carbonyl groups.

Grafting of softwood kraft pulps fibers with fatty acids under cold plasma conditions.

Cold plasma treatment is used to modify the cellulosic fibers for a variety of applications. The grafting of softwood unbleached (UBP) and bleached (BP) kraft pulp fibers has been performed under the action of cold plasma discharges, using different kinds of fatty acids. The grafted samples are characterized by FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), termogravimetry (TG-DTG) and X-ray diffraction (XRD). All these methods confirm the morphological and structural changes after plasma treatment which determines the modification in cellulosic fiber properties. The active centers created within the cellulose chains by plasma treatment were used to initiate grafting reactions with fatty acids. Such modification is useful to enhance the fibers properties such as softness and to change hydrophilic/hydrophobic balance.

Biomaterials based on new polyurethane and hydrolyzed collagen, k-elastin, hyaluronic acid and chondroitin sulfate.

In this paper biomaterials based on various polyurethane formulations have been physically characterized by FT-IR spectroscopy, contact angle measurements, DSC, TG/DTG and SEM methods. It has been established that the transition temperatures of soft and hard segments of polyurethane (glass transition or melting) depend on the blend composition. The melting temperature varies from 54.2 to 81.9°C for soft segments, and from 220 to 235°C for hard segments. FT-IR spectrometry allows identifying the functional groups involved in interactions and consequently the changes in polymer chain mobility. From SEM images, is evident that polyurethanic film is porous and spongious. By adding of the others components such as hydrolyzed collagen, elastin, chondroitin sulfate or hyaluronic acid, a reduction of porosity of films was obtained.