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Two novel self-emulsifying drug delivery systems (SEDDS) with atorvastatin calcium, an anti-hyperlipidemic drug, were obtained and adsorbed on different solid inorganic carriers. In order to determine the parameters affecting the drug release process, different physicochemical analyses were performed. Liquid SEDDS were investigated for water solubilization capacity, viscosity and surface tension. In the case of solid materials, differential scanning calorimetry and scanning electron microscopy were conducted in order to check the samples for the presence of drug crystals. The interactions between the components of the materials were analyzed with inverse gas chromatography and Flory-Huggins parameters were calculated. The drug release experiments performed for all investigated formulations revealed that after the initial quick release the drug concentration in the dissolution medium decreased slightly which might be related to the crystallization process. However, the level of the released active ingredient was maintained at 80% for most formulations. It was also shown that the results of drug dissolution studies were independent of the measured physicochemical parameters, even though some clear differences have been observed between the analyzed materials.

Development of generic extended-release (ER) formulations is challenging. Especially under fed conditions, the risk of failure in bioequivalence trials is high because of long gastric residence times and susceptibility to food effects. We describe the development of a generic trazodone ER formulation that was aided with a biorelevant dissolution evaluation. Trazodone hydrochloride 300-mg monolithic matrix tablets were dissolved both in USP and EMA compliant conditions and in the StressTest device that simulated both physicochemical and mechanical conditions of the gastrointestinal passage. The final formulation was tested against the originator, Trittico XR 300 mg, in a randomized cross-over bioequivalence trial with 44 healthy volunteers, in agreement with EMA guidelines. Initially developed formulations dissolved trazodone similarly to the originator under standard conditions (f2 factor above 50), but their dissolution kinetics differed significantly in the biorelevant tests. The formulation was optimized by the addition of low-viscosity hypromellose and mannitol. The final formulation was approved for the bioequivalence trial. Calculated Cmax were 1.92 ± 0.77 and 1.92 ± 0.63 [μg/mL], AUC0-t were 27.46 ± 8.39 and 29.96 ± 9.09 [μg∙h/mL], and AUC0-∞ were 28.22 ± 8.91 and 30.82 ± 9.41 [μg∙h/mL] for the originator and test formulations, respectively. The 90% confidence intervals of all primary pharmacokinetic parameters fell within the 80–125% range. In summary, biorelevant dissolution tests supported successful development of a generic trazodone ER formulation pharmaceutically equivalent with the originator under fed conditions. Employment of biorelevant dissolution tests may decrease the risk of failure in bioequivalence trials of ER formulations. Electronic supplementary material The online version of this article (10.1208/s12249-020-01662-8) contains supplementary material, which is available to authorized users.

Currently marketed drug-eluting stents are non-selective in their anti-restenotic action. New active substance introduction to polymeric stents and vascular grafts can promote early re-endothelialization, crucial in preventing implant restenosis. Additionally, managing material hydrophobicity by blending synthetic polymers limits adverse effects on bulk properties and controls active substance release. However, the influence of hydrophilic synthetic polymer on human cells in the cardiovascular system remains to be determined. In this report, effects of both poly(e-caprolactone) (PCL) fibers hydrophilization with Pluronic P123 (P123) and cilostazol (CIL) loading were studied. Physicochemical and mechanical properties of electrospun tubular structures produced from PCL and PCL/P123 fibers with and without CIL were investigated and compared. Release profiles studies and in vitro cell proliferation assays of electrospun materials were conducted. It was found that P123 located near the surface of electrospun fibers increased the rate of CIL release. PCL formulation sustained human umbilical vein endothelial cells (HUVEC) growth for 48 h. Despite improved hydrophilicity, PCL/P123 formulations were found to reduce HUVEC viability. Both PCL and PCL/P123 materials reduced primary aortic smooth muscle cells (PASM) viability after 48 h. In PCL formulations containing CIL, drug release caused a decrease in PASM viability. P123 blending with PCL was found to be as a useful pre-fabrication technique for modulating surface hydrophobicity of electrospun materials and the release profile of incorporated active substance. The cytotoxicity of P123 was evaluated to improve the design of drug-loaded vascular grafts for cardiovascular applications.

Nanosizing is an approach to improve the dissolution rate of poorly soluble drugs. The first aim of this work was to develop nanosuspension of cilostazol with liquid antisolvent precipitation (LASP) and its combination with ultrasound. Second, to systematically study the effect of bottom-up processing factors on precipitated particles’ size and identify the optimal settings for the best reduction. After solvent and stabilizer screening, in-depth process characterization and optimization was performed using Design of Experiments. The work discusses the influence of critical factors found with statistical analysis: feed concentration, stabilizer amount, stirring speed and ultrasound energy governed by time and amplitude. LASP alone only generated particle size of a few microns, but combination with ultrasound was successful in nanosizing (d10 = 0.06, d50 = 0.33, d90 = 1.45 µm). Micro- and nanosuspension’s stability, particle morphology and solid state were studied. Nanosuspension displayed higher apparent solubility than equilibrium and superior dissolution rate over coarse cilostazol and microsuspension. A bottom-up method of precipitation-sonication was demonstrated to be a successful approach to improve the dissolution characteristics of poorly soluble, BCS class II drug cilostazol by reducing its particle size below micron scale, while retaining nanosuspension stability and unchanged crystalline form.

In the mucoadhesive drug delivery systems the controlling mechanism is initiated by the wetting and swelling of the polymer matrix. In view of the above, the aim of our study was to analyze the effect of model saliva and gastric fluids on the wetting properties and sorption of selected mucoadhesive (Carbopol 974P NF, HEC) and film-forming (Kollidon VA 64) polymers as well as their blends. We considered two types of examined materials: individual polymers and their blends in the form of powders as well as in the form of compressed discs (blanc tablets). The contact angle measurements for powders were performed according to the Washburn method, using the capillary rise technique, whereas the sessile drop method was applied to the compressed discs of mucoadhesive polymers. The surface energy was determined by the OWRK method. The influence of composition of the polymer blends and pH of model fluids on the wetting properties and sorption of the polymer formulations was evaluated. Moreover, significant differences in the morphology, surface roughness and surface properties of mucoadhesion polymers considered were discussed.

The surface properties play a particularly important role in the mucoadhesive drug delivery systems. In these formulations, the adsorption of polymer matrix to mucous membrane is limited by the wetting and swelling process of the polymer structure. Hence, the performance of mucoadhesive drug delivery systems made of polymeric materials depends on multiple factors, such as contact angle, surface free energy and water absorption rate. The aim of our study was to analyze the effect of model saliva and vaginal fluids on the wetting properties of selected mucoadhesive (Carbopol 974P NF, Noveon AA-1, HEC) and film-forming (Kollidon VA 64) polymers as well as their blends at the weight ratio 1:1 and 1:1:1, prepared in the form of discs. Surface properties of the discs were determined by measurements of advancing contact angle on the surface of polymers and their blends using the sessile drop method. The surface energy was determined by the OWRK method. Additionally, the mass swelling factor and hydration percentage of examined polymers and their blends in simulated biological fluids were evaluated.

Niacin (nicotinic acid, NA) is administered orally as an antihyperlipidemic agent in extended-release (ER) tablets in high doses. Due to rapid absorption and extensive metabolism (non-linear pharmacokinetics), the drug plasma levels are highly variable, which may correlate with side effects. Interestingly, this erratic drug delivery behavior of niacin ER products cannot be clarified by compendial in vitro release testing. The standard dissolution tests do not allow to mimic the selected GI tract characteristics in order to estimate the robustness of formulation under the variability of the physiological conditions. These are characterized by the pH value, impact of motility forces and composition, as well as volume of GI liquids. Our paper demonstrates a comparison of a newly developed ER HPMC niacin formulation with an originator product. The research aimed to design a robust matrix tablet of comparable biopharmaceutical behavior, safety and efficacy. The extensive in vitro investigation, including dynamic studies in flow-through cell apparatus and stress test device, forms the basis for the evaluation of nicotinic acid plasma concentrations in vivo. The occurrence of erratic, multiple NA plasma peaks after the administration of both extended-release products is a result of its local input excess over the metabolic threshold (at the level corresponding to maximum 2% of the administered dose, i.e., 20 mg of drug) due to the mechanical stresses of physiological intensity. We demonstrate how this behavior is similar for both marketed and test products. In this context, we describe how a robust ER matrix and well-designed formulation does not guarantee the test product’s bioequivalence to the comparator one out of reasons unrelated to technology and biopharmaceutical properties, but because of the active compound’s intrinsic pharmacokinetic characteristics, i.e., highly variable, extensive metabolism of nicotinic acid. Electronic supplementary material The online version of this article (10.1208/s12249-019-1600-z) contains supplementary material, which is available to authorized users.

A liquid chromatography-tandem mass spectrometry analytical method was developed for the simultaneous determination of five parabens and four bisphenols in human breast milk samples in both free forms and as the total concentration, which included also conjugated compounds. The samples for the determination of free forms were extracted directly using the QuEChERS method, while the determination of the total content included a preliminary enzymatic hydrolysis step. Breast milk was sampled 3-6 weeks and 3 months after delivery. Methylparaben was the most abundant paraben with an average total concentration in the two sampling points 1.02 and 1.52 ng mL-1, respectively. Bisphenol A was the most abundant bisphenol with an average total concentration in the two sampling points 1.91 and 1.41 ng mL-1, respectively. For the first time, the hazard quotients were calculated for these compounds in the breast milk samples demonstrating that bisphenol A contributed the most to the hazard caused by the tested compounds. However, the hazard index calculated for the cumulative impact indicates that the milk samples were safe for the children.

The review discusses the progress in the design and synthesis of bioactive agents incorporated into vascular grafts obtained by the electrospinning process. Electrospun fibers can be applied as an artificial extracellular matrix for tissue engineering and drug delivery, improving tissue regeneration and therapeutic outcomes. A large number of active substances are loaded into the fibers, such as growth factors, heparin, NO donors, statins, antibiotics or anti-inflammatory agents. There are various methods for bioactive substance incorporation including direct blending, emulsion, and coaxial electrospinning as well as covalent and non-covalent binding of the bioactive molecules to the fiber surface. The release mechanism of the drug depends on the synthesis route, active substance properties, and polymer matrix nature. The electrospun materials represent a very promising building block for the fabrication of effective vascular prosthesis in the near future.

Interactions occurring between components in the quaternary powder mixtures consisting of perindopril tert-butylamine, indapamide (active pharmaceutical ingredients), carrier substance and hydrophobic colloidal silica were examined. Two grades of lactose monohydrate: Spherolac(®) 100 and Granulac(®) 200 and two types of microcrystalline cellulose: M101D+ and Vivapur(®) 102 were used as carriers. We determined the size distribution (laser diffraction method), morphology (scanning electron microscopy) and a specific surface area of the powder particles (by nitrogen adsorption-desorption). For the determination of the surface energy of powder mixtures the method of inverse gas chromatography was applied. Investigated mixtures were characterized by surface parameters (dispersive component of surface energy, specific interactions parameters, specific surface area), work of adhesion and cohesion as well as Flory-Huggins parameter χ23('). Results obtained for all quaternary powder mixtures indicate existence of interactions between components. The strongest interactions occur for both blends with different types of microcrystalline cellulose (PM-1 and PM-4) while much weaker ones for powder mixtures with various types of lactose (PM-2 and PM-3).

SBA-16 and two modified SBA-16 type ordered mesoporous silica were used as the carriers for ibuprofen (anti-inflammatory drug) and furosemide (loop diuretic drug). Modification of the solid carrier was prepared with chitosan or N-3[(amino(poly-propylenoxy)]aminopropyltrimethoxysilane. The samples of carriers and carrier-drug loaded materials were characterized by X-ray diffraction, N2 adsorption, Fourier-transform infrared spectroscopy, thermogravimetry, and differential scanning calorimetry. The release profiles of active pharmaceutical ingredients were performed in media with different pH in the USP 2 apparatus as well as in two biorelevant media (fasted state simulated gastric fluid and fasted state small intestinal fluid) in USP 4 apparatus. The loading of active substances into mesoporous materials was performed with modified immersion method. The maximum content of deposited drug in mesoporous material was close to 12.0 and 2.2 wt.% for ibuprofen and furosemide, respectively. After drug adsorption, the reduction of BET surface area, pore volume and pore diameter of non-modified and modified SBA-16 was observed, while the cubic arrays of siliceous matrix were well preserved. The release profiles of ibuprofen and furosemide loaded in mesoporous materials in media with different pH and biorelevant fasted state simulated gastric fluid and fasted state small intestinal fluid showed that the new SBA-16 type materials modify the release profiles of furosemide, increasing the dissolution rate of these substances in the medium at pH 1.2. The cytotoxicity of the materials and permeability of drugs after their loading on SBA-16 materials were evaluated on Caco-2 model. The results of our study showed that mesoporous materials did not exert cytotoxic effects and did not influence on the permeability of both active pharmaceutical ingredients in relation to pure substances.

This work describes the synthesis of SBA-16 modified with amine groups and chitosan. The synthesized materials were characterized by small angle XRD (SXRD), wide angle XRD (WXRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier-transformed Infra-red (FTIR) spectroscopy and nitrogen adsorption/desorption techniques. The characterization results revealed that the new materials show highly ordered mesostructure with large surface area and pore diameter, suitable for further applications. FTIR, WXRD, TGA data and elemental analyses proved that amine groups/chitosan were uniformly dispersed on SBA-16 surface. The materials obtained can be considered as safe, on the basis of insignificant cytotoxic effect against a human colon cancer cell line Caco-2. The preliminary tests have shown that the SBA-16 materials are able to modify the release profile of furosemide (FUR), a poorly soluble active substance of Class IV of the Biopharmaceutics Classification System (BCS).

The aim of our study was to examine the irritation potential of new eye drops containing 2% choline salicylate (CS) as an active pharmaceutical ingredient (API) and various polymers increasing eye drop viscosity (hydroxyethylcellulose, hydroxypropyl methylcellulose, methylcellulose, polyvinyl alcohol, polyvinylpyrrolidone). The standard method for assessing the potential of irritating substances has been the Draize rabbit eye test. However the European Centre for Validation of Alternative Methods and the Coordinating Committee for Validation of Alternative Methods recommend, short time exposure (STE) in vitro tests as an alternative method for assessing eye irritation. The eye irritation potential was determined using cytotoxicity test methods for rabbit corneal cell line (SIRC) after 5min exposure. The viability of cells was determined using two cytotoxicity assays: MTT and Neutral Red Uptake. According to the irritation rankings for the short time exposure test, all tested eye drops are classified as non-irritating (cell viability >70%).

Fabrication of scaffolds loaded with nitric oxide (NO) donors (S-nitrosoglutathione, GSNO, and isosorbide mononitrate, ISMN) with suitable cell compatibility and optimized properties for tissue-engineering applications is reported using “in situ” technique. Based on FDA-approved polymer, solvent and dosage forms, this gentle process allowed the incorporation of the GSNO labile drug into scaffolds made of either poly(lactide-co-glycolide) (PLGA) or PLGA/poly(ɛ-caprolactone) (PCL) blend. During scaffolds manufacturing process including washing cycles, NO donors were leached from scaffolds. However, GSNO and ISMN concentrations in the last washing medium (10−7 M and 10−4 M, respectively) were in the range of cell suitability for tissue engineering. Further morphological analyses indicated that smoother surfaces with fewer but bigger pores (compatible with cell penetration and ingrowth) were obtained with PLGA in comparison with PLGA/PCL scaffolds. Among all tested matrices, only unloaded PLGA and GSNO-loaded PLGA/PCL exhibited intermediate cell anchorage, with mitochondrial activity close to the control and an increase in protein content, a prognostic for scaffold cell colonization, defining them as promising candidates. Deeper analyses of these two scaffolds looking at intracellular redox balance through reactive oxygen species production, glutathione, S-nitrosothiols, and nitrite ions content exhibited GSNO-loaded PLGA/PCL as the best of all tested 3D scaffolds for tissue engineering.

International audience; A one-pot synthetic approach was developed to prepare water-dispersible core/shell CdTexS1-x/ZnS QDs using CdCl2, Zn(OAc)2, NaHTe and 3-mercaptopropionic acid (MPA) as starting materials. Sulfide S2- ions produced from the partial decomposition of MPA associate to CdTe nuclei to form an alloyed CdTexS1-x core before reacting with Zn2+ ions to generate the ZnS shell. The photoluminescence (PL) of CdTexS1-x/ZnS QDs QDs can be adjusted from the green to the near-infrared region by varying the ratio of precursors or the reaction time. The formation of core/shell CdTexS1-x/ZnS structure was confirmed by high resolution transmission electron microscopy and X-ray diffraction studies. The highly luminescent QDs (PL quantum yields up to 35%) exhibit good stability in aqueous solution and low cytotoxicity towards Kluyveromyces bulgaricus cells. Bioconjugation of CdTexS1-x/ZnS QDs with (D)-(+)-galactose was successfully applied for the fluorescent imaging of the yeast cells.

Purpose The study discusses the value of electrospun cilostazol-loaded (CIL) polymer structures for potential vascular implant applications. Methods Biodegradable polycaprolactone (PCL) fibers were produced by electrospinning on a rotating drum collector. Three different concentrations of CIL: 6.25%, 12.50% and 18.75% based on the amount of polymer, were incorporated into the fibers. The fibers were characterized by their size, shape and orientation. Materials characterization was carried out by Fourier Transformed Infrared spectroscopy (FTIR), Raman spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). In vitro drug release study was conducted using flow-through cell apparatus (USP 4). Results Three-dimensional structures characterized by fibers diameter ranging from 0.81 to 2.48 μm were in the range required for cardiovascular application. DSC and XRD confirmed the presence of CIL in the electrospun fibers. FTIR and Raman spectra confirmed CIL polymorphic form. Elastic modulus values for PCL and the CIL-loaded PCL fibers were in the range from 0.6 to 1.1 GPa. The in vitro release studies were conducted and revealed drug dissolution in combination with diffusion and polymer relaxation as mechanisms for CIL release from the polymer matrix. Conclusions The release profile of CIL and nanomechanical properties of all formulations of PCL fibers demonstrate that the cilostazol loaded PCL fibers are an efficient delivery system for vascular implant application. Electronic supplementary material The online version of this article (10.1007/s11095-017-2314-0) contains supplementary material, which is available to authorized users.

Vitamin D (VD) is a fat-soluble prohormone well known for its role in regulating calcium and phosphate metabolism. It has been clinically used for many years to prevent rickets in children, osteomalacia, and osteoporosis in adults. VD insufficiency is a common medical condition, and many supplements are available in the market in order to increase serum 25-hydroxy VD levels to recommended amounts. Over the course of the last decades, it has become increasingly clear that calcitriol, an active form of VD, regulates multiple cellular processes with effects on normal and malignant cell growth and differentiation, and on the immune and cardiovascular function. Increasing evidence supports the role of the VD system in cancer prevention and therapy. Due to many pleiotropic and beneficial effects in extra-skeletal disorders, VD has gained potential and become an interesting active for encapsulation into drug delivery systems. The purpose of this review is to present the diversity of drug delivery systems that have been reported for VD or VD derivatives in an orderly manner across the following categories: Oral administration, application on the skin, cancer prevention/therapy, and other diseases or routes of administration.

International audience; Nitric oxide (NO) produced by endothelial nitric oxide synthase (eNOS) activates signaling pathways responsible for smooth muscle cell relaxation, leading to vasodilation and thus plays an important role in controlling vascular homeostasis, thrombosis and inflammation.Recent studies indicate that S-nitrosothiols produced in vivo as well as synthetic ones might be important reservoirs of NO. Based on a broad range of NO functions within the living organisms, this review highlights the impact of S-nitrosothiols on cardiovascular cell cycle. The cell membrane transport and the decomposition patterns responsible of S-nitrosothiols actions are presented. The effects of NO delivery through S-nitrosothiols have a significant potential in cardiovascular diseases with various underlying causes. The challenges related to their application in the pharmacotherapy of patients with various cardiovascular diseases are also discussed.

International audience; 3-Mercaptopropionic acid-capped core/shell ZnS:Cu/ZnS and ZnS:Mn/ZnS doped quantum dots (QDs) prepared through hydrothermal methods exhibit high photoluminescence intensity as well as good photostability. These water-dispersible nanoparticles exhibit high fluorescence sensitivity to folic acid due to the high affinity of the carboxylate groups and nitrogen atoms of folic acid towards the Zn surface atoms of the doped dots. Quenching of the fluorescence intensity of the QDs allows the detection of folic acid concentrations as low as 11 mu M, thus affording a very sensitive system for the sensing of this biologically active molecule in aqueous solution. The possible quenching mechanism is discussed.

Polychlorinated biphenyls (PCBs) are present in the environment as complex mixtures, which make it challenging to identify PCB congeners that may be subject to active transport processes. Here we employ a transgenic mouse model in combination with multivariate analyses to investigate if chiral PCBs 91, 95, 132, 136, 149, 174, 176 and 183 are subject to active (enantioselective) transport by multidrug resistance (MDR) transporters. A synthetic PCB mixture containing these congeners was administered orally to female FVB or mdr1a/1b knockout mice. Due to the short half-life of chiral PCB congeners, mice were euthanized after 24h and PCB concentrations and enantiomeric fractions were determined in selected tissues and excreta. Principal component analysis did not reveal differences between wild-type and mdr1a/1b knockout mice. However, Hotelling T2-test revealed significantly lower PCB concentrations and a more pronounced enantiomeric enrichment in the adipose tissue of mdr1a/1b knockout mice. These differences are due to higher body weights and higher fecal fat contents of mdr1a/1b knockout mice. Analysis of the enantiomeric fractions of PCBs 91, 95, 136, 149 and 174 showed a significant enantiomeric enrichment for all five congeners in wild-type and mdr1a/1b knockout mice. Overall, by studying a PCB mixture in a transgenic mouse model in combination with a multivariate data reduction approach, PCBs 91, 95, 136, 149 and 174 could be excluded as substrates of multidrug resistance transporters 1a/b. Keywords: Polychlorinated biphenyls, Enantiomeric fraction, Atropisomers, Fecal fat content, Multivariate analysis, Chemometrics, Principal component analysis, Hotelling T2-test, Transgenic mice, Active transport, Multidrug resistance transporters

Signaling pathways in living cells which regulate cell cycle and activate defense mechanisms against environmental stresses are mainly controlled through cell redox potential status. The main cellular redox buffer is constituted by oxidized/reduced glutathione system (GSSG/2GSH). Physiological functions and pathological situations resulting from oxidative stress are driven by glutathione homeostasis and its dysfunction, respectively. Many methodologies devoted to the investigation of cellular redox potential relying on the determination of reduced and oxidized glutathione concentrations measured in various cellular compartments, tissues and organs have been reported. Most of them are till now based on separative and non-separative techniques and include extractive step from biological samples. They are time-consuming and tedious in order to preserve reduced to oxidized glutathione ratio, thus introducing bias in its evaluation. New trends are focused on in situ evaluation of redox state especially through the monitoring of glutathione pool. This review reports recent developments in fluorescence imaging of cellular redox state, especially those involving nanotechnologies.

This work describes some results of identification and determination of bisphenol A (BPA) in powdered milk by applying the gas chromatography. To determine BPA contents in the milk and to reduce the matrix interference associated with the constituents of the powdered milk, we performed the following activities. First, we ultra-centrifuged the dissolved milk solutions. Next, we preconcentrated the analyte in the supernatant using a C(18) and new sorbent with chemically bonded ketoimine group solid phase extraction column. Finally, we used gas chromatography for the determination of BPA in the samples under study. A recovery of bisphenol A from spiked milk samples was also performed, with recovery result located at 91% +/- 3%/94% +/- 2%.

The levels of organochlorinated pesticides (OCPs): p,p′-DDT and its metabolites, hexachlorobenzene (HCB), hexachlorocyclohexane isomers (HCHs), chlordanes and their metabolites, and 18 polychlorinated biphenyl (PCB) congeners were measured in maternal serum, umbilical cord serum and human milk collected from 22 mothers living in the Wielkopolska region, Poland. Additionally, 11 polybrominated diphenyl ether (PBDE) congeners were measured in the human milk samples. p,p′-DDT and its major metabolite, p,p′-DDE, together with HCB, were found in all milk and serum samples. Median concentrations of p,p′-DDE in maternal serum, umbilical cord serum and milk were 343, 329 and 634 ng/g lipid weight (lw). PCB congeners 138, 153 and 180 were the major congeners measured in all serum samples, while CB 170 was detected in 74% and 100% of umbilical cord and maternal serum, respectively. Except for CBs 74, 101 and 105, which had a detection frequency of 77%, 23% and 82%, respectively, all investigated PCB congeners were measured in all human milk samples. The median concentrations of sum PCBs in maternal serum, umbilical cord serum and milk were 79, 60 and 133 ng/g lw, respectively. A good correlation (Spearman RS > 0.75, p < 0.001) was found for major PCBs, p,p′-DDT and p,p′-DDE, between maternal and umbilical cord serum, while the correlation was weaker between milk and serum. The median of sum PBDEs in human milk was 2.0 ng/g lw (range 0.8 to 8.4), with BDE 47 being always the most abundant PBDE congener and, together with BDE 153, being present in all samples. In general, results found in the investigated group are at the low end of the concentration range measured in Europe.

Selective fluorogenic probes for the labelling of intracellular reduced glutathione (GSH), i.e. ortho-phthaldialdehyde (OPA) and naphthalene-2,3-dicarboxaldehyde (NDA), have been encapsulated in polymeric nanoparticles (NPs) and the ability of the NPs to enhance uptake of the probe by microbial cells has been evaluated. Preparation of the probe-loaded NPs composed of Eudragit(®) E was based on an oil-in-water emulsification solvent evaporation method using an ultrasonic probe and polyvinyl alcohol as the surfactant. The encapsulation efficiency of the probes in lyophilized NPs was determined using high performance liquid chromatography (HPLC). A higher encapsulation rate of NDA than OPA was found: 47.6 ± 9.9 (n = 6) and 2.1 ± 0.2% (n = 3), respectively. The NDA-loaded particle diameter and zeta potential were 224.6 ± 14.7 nm and +40.9 ± 6.5 mV, respectively. After 20 min incubation of cultured Candida albicans yeast cells with either free NDA or NDA-loaded NPs (final NDA concentration 100 µM), cells were harvested and corresponding lysates were analysed using HPLC coupled with spectrofluorimetric detection. Incubation of cells with NDA-loaded NPs increased intracellular levels of NDA-GSH adduct by about nine-fold in comparison with the free probe. Adhesion on the cells and the penetration behaviour of NPs loaded with either NDA or fluorescent label (Nile Red) were characterized qualitatively by confocal laser scanning microscopy.

The database of the relative retention times (RRTs) of polychlorinated biphenyls (PCBs) reported in literature was used to calculate the retention indices (RIs) of all 209 PCB congeners on temperature programmed capillary column Rtx-5. Calculation of retention indices was based on reference series of seven congeners (PCB IUPAC Nos. 18, 52, 101, 143, 185, 203 and 206) that exhibit linear relative retention time behaviour as a function of chlorine number. The calculated indices were compared to those determined in our laboratory as well as to those obtained by other authors. The proposed indices system was applied for identification individual congeners in mixture of Aroclors 1242:1254:1260, using only reference series of PCBs.

A method for determination of trace concentrations of individual PCB congeners in human milk was validated. The analytical procedure included the following steps: acetone : hexane extraction, clean-up of extracts with concentrated sulfuric acid and solid phase extraction (SPE) on Florisil. The identification and quantification of analytes in purified extracts were carried out by high-resolution gas chromatography (HRGC) with electron capture detection (ECD) and/or with low-resolution mass spectrometry (LRMS). Recoveries of 14 PCB congeners from spiked cow milk samples, based on HRGC-ECD were between 87.3 and 93.6%. The precision of analyte determination was established as close to or less than 10%. The detection limits ranged between 0.14 and 0.26 ng/g fat and the quantification limits between 0.57 and 0.86 ng/g fat. The method was linear and characterized by good correlation coefficients (>0.99) for most of the compounds studied. The quality of the method under validation was verified by the analysis of ...

International audience; The interaction of thiols (glutathione, cysteine, and cysteamine) with yellow-emitting siloxane-capped ZnO QDs was studied. A gradual enlargement of the PL emission band resulting in white-light emission was observed upon reaction with thiols, while the diameter (ca. 4 nm) and the crystallinity of the dots were not affected. The appearance of broad white-emission was accompanied by a decrease of the photoluminescence quantum yield from 16% to 5-6%. Generation of surface defect states through interaction of the thiols with Zn surface atoms of the dots provoking shrunk of the siloxane capping may be responsible of that broadband emission throughout most of the light spectrum.

The aim of our study was to obtain the data on the exposure of breast-fed infants to polychlorinated biphenyls (PCBs) and selected organochlorine pesticides (OCPs) in the Wielkopolska province (Poland). The levels of indicator PCBs, and selected OCPs, including two DDT metabolites (HCB, p,p'-DDT, p,p'-DDD, p,p'-DDE and alpha,beta,gamma-HCH) were determined in 27 human milk samples, collected in 2000-2001, according to WHO protocol. Estimated daily intakes (EDIs) of all analytes were calculated. Our results were compared with those obtained by an analysis of human milk samples from other European and non-European countries, collected in the same period time. We have stated that median exposure of Wielkopolska first breast-fed infants to OCPs is comparable (EDI(HCB) = 0.086 microg/kgbw/day; EDI(beta-HCH)=0.063 microg/kgbw/day) or higher (EDI(p,p'-DDE) = 3.495 microg/kgbw/day) than in other European countries, while exposure to PCBs (EDI(Sigma7PCB) = 0.364 microg/kgbw/day) is situated at the low end of the intake of these xenobiotics by breast-fed infants from different regions of Europe.

The present work was aimed to the development of a fluorescence assay using the universal 96-well microplate format, for the measurement of reduced glutathione (GSH) in yeast cells. The method relies upon the reaction between GSH and a highly selective fluorogenic probe, i.e. naphthalene-2,3-dicarboxaldehyde (NDA). The optimization of the method included the extraction step of GSH from cultured yeast cells in a cold perchloric acid solution, derivatization conditions (10-min reaction at pH 8.6 and at 20 ± 2 °C in darkness) and stability studies of the resulting fluorescent adduct. Full selectivity was observed versus other endogenous thiols (except for γ-glutamylcysteine), glutathione disulfide (GSSG) and enzymatic reducing reagents of GSSG. Linearity was verified in the range 0.3–6.5 μM (R2 > 0.98) and limits of quantification and detection were 0.3 and 0.05 μM, respectively. Relative standard deviation corresponding to repeatability (n = 3) and inter-day precision (n = 5) were 2.8 and 6.1%, respectively. Mean GSH recovery from cell extracts was 95%. The method appeared highly correlated (R2 = 0.96) with a previously reported HPLC method. The method was then applied to the monitoring of GSH in the yeast strain Kluyveromyces lactis during its growth period and in the presence of an inhibitor of GSH biosynthesis. The method presents the main advantage of a high throughput for the measurement of biological samples. The extent of the method to the study of the redox couple GSSG/GSH by including an enzymatic reduction step and the enhancement of the fluorescence signal using cyclodextrins were discussed.

Topological parameters (Balaban index and electrotopological index) were used as structural parameters in the structure-retention relationships (SRRs). These relationships were found to be statistically valid and useful in the prediction of retention data of polychlorinated biphenyls (PCBs) despite of the temperature program used in the gas chromatographic experiment.