Development and in vitro evaluation of donepezil hydrochloride-loaded thermo-responsive polymer grafted molybdenum disulfide nanosheets: Modeling using response surface methodology.

Nanocarriers are utilized to deliver bioactive substances in the treatment of neurodegenerative diseases such as Alzheimer's. In this work, we prepared donepezil hydrochloride-loaded molybdenum disulfide modified thermo-responsive polymer as the thermo-responsive nanocarrier. Then, glycine was grafted to the surface of the polymer to improve the targeting and sustained release. The morphology, crystallinity, chemical bonding, and thermal behavior of nanoadsorbent were fully characterized by field emission scanning electron microscopes, energy dispersive X-ray, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermo-gravimetric measurement. Response surface methodology with the central composite design was applied to optimize the sorption key factors such as pH solution (A: 5-9), contact time (B: 10-30 min), and temperature (C: 30-50 °C). Non-linear isotherm modeling confirmed that the sorption of the drug follows the Ferundlich model based on higher correlation coefficient values (R2 =0.9923) and lower errors values (root means square errors: 0.16 and Chi-square: 0.10), suggesting a heterogeneous multilayer surface sorption. The non-linear sorption kinetic modeling revealed that the pseudo-second-order kinetic model well-fitted the sorption data of the drug on the nanoadsorbent surface based on higher R2 values (R2 =0.9876) and lower errors values (root means square errors: 0.05 and Chi-square: 0.02). The in vitro drug release experiment of donepezil hydrochloride shown that about 99.74 % of drug release was found to be occurred at pH= 7.4 (T = 45 °C) within 6 h, whereas about 66.32 % of drug release occurred at pH= 7.4 (T = 37 °C). The release of donepezil hydrochloride from as prepared drug delivery system has shown a sustained release profile, which was fitted to Korsmeyer-Peppas kinetics.

Development of p-amino acetanilide functionalized multi-walled carbon nanotubes as an effective carrier for lansoprazole release.

Nowadays the nano-drug delivery system is an appropriate procedure for solving the problem of controlling drug performance in a traditional method. For this purpose, a new nano-adsorbent of modification multi-walled carbon nanotubes with cyanuric chloride and para-amino acetanilide was synthesized for the effective sorption and desorption of lansoprazole drugs. Physicochemical properties of the multi-walled carbon nanotubes with cyanuric chloride and para-amino acetanilide were then specified with energy dispersive spectroscopy, scanning electron microscope, infrared spectroscopy (IR), thermal gravimetric (TGA), and elemental analysis (CHN). The adsorption process followed by the drug release kinetics and isotherm models has indicated a good and acceptable kinetic adsorption and Langmuir isotherm model in conditions simulated. The maximum capacity value for the lansoprazole adsorption by nano-adsorbent was 48.781 mg g-1at an optimal pH of 6. The result of the drug release mechanism was shown in the first 30 min in the stomach is as much as 30% of the drug is released into the environment by MT-CC/pA. The efficiency and adsorption capacity of the produced nano-adsorbent is extremely high for lansoprazole sorption.

In vitro evaluation of copper sulfide nanoparticles decorated with folic acid/chitosan as a novel pH-sensitive nanocarrier for the efficient controlled targeted delivery of cytarabine as an anticancer drug.

Nanoparticles (NPs) have gained more attention as drug delivery systems. Folic acid (FA)-chitosan (CS) conjugates, because of their biodegradability, low toxicity, and better stability, offer a pharmaceutical drug delivery tool. The aim of this work was to fabricate CuS NPs modified by CS followed by grafting FA as a nanocarrier for the delivery of cytarabine (CYT) as an anticancer drug. In this work, CuS NPs modified by CS and FA were successfully synthesized. The structural properties of the nanocarrier were characterized by using scanning electron microscopy, Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, and Brunauer-Emmett-Teller. The adsorption mechanism of CYT by adsorption isotherms, kinetics, and thermodynamics was deliberated and modeled. The in vitro CYT release behavior for the nanocarrier was 99% and 61% at pH 5.6 and 7.4, respectively. The adsorption behavior of CYT by CuS NPs -CS-FA was well explored by pseudo-second-order kinetic and Langmuir isotherm models by the coefficient of determination (R2 > 0.99). Thermodynamic results showed that the uptake of CYT by CuS NPs-CS-FA was endothermic and spontaneous. The experimental results showed that CYT/CuS NPs -CS-FA can be proposed as an efficient nanocarrier for the targeted delivery of anticancer drugs.

Temperature-responsive graphene oxide/N-isopropylacrylamide/2-allylphenol nanocomposite for the removal of phenol and 2,4-dichlorophenol from aqueous solution.

In this study, a novel thermo-responsive polymer was synthesized with efficient grafting of N-isopropylacrylamide as a thermosensitive polymer onto the graphene oxide surface for the efficient removal of phenol and 2,4-dichlorophenol from aqueous solutions. The synthesized polymer was conjugated with 2-allylphenol. Phenol and 2,4-dichlorophenol were monitored by ultra-performance liquid chromatography system equipped with a photodiode array detector. The nanoadsorbent was characterized by different techniques. The nanoadsorbent revealed high adsorption capacity where the removal percentages of 91 and 99% were found under optimal conditions for phenol and 2,4-dichlorophenol, respectively (for phenol; adsorbent dosage = 0.005 g, pH = 8, temperature= 25 °C, contact time = 60 min; for 2,4-dichlorophenol; adsorbent dosage = 0.005 g, pH = 5, temperature = 25 °C, contact time = 10 min). Adsorption of phenol and 2,4-dichlorophenol onto nanoadsorbent followed pseudo-second-order kinetic and Langmuir isotherm models, respectively. The values of ΔG (average value = - 11.39 kJ mol-1 for phenol and 13.42 kJ mol-1 for 2,4-dichlorophenol), ΔH (- 431.72 J mol-1 for phenol and - 15,721.8 J mol-1 for 2,4-dichlorophenol), and ΔS (35.39 J mol-1 K-1 for phenol and - 7.40 J mol-1 K-1 for 2,4-dichlorophenol) confirmed spontaneous and exothermic adsorption. The reusability study indicated that the adsorbent can be reused in the wastewater treatment application. Thermosensitive nanoadsorbent could be used as a low-cost and efficient sorbent for phenol and 2,4-dichlorophenol removal from wastewater samples.

Green biosynthesis of magnetic iron oxide nanoparticles using Mentha longifolia for imatinib mesylate delivery.

In this work, the rapid, facile, and eco-friendly green process was introduced in the preparation of ß-cyclodextrin/magnetic iron oxide nanoparticles by using the aqueous Mentha longifolia extracts of Mentha longifolia. The obtained nanoparticles were characterised by Fourier transform infrared spectroscopy, x-ray powder diffraction, field emission scanning electron microscope, and thermogravimetric analysis. Also, effective factors on the synthesis of magnetic nanocomposites including temperature, concentration of the Mentha longifolia extract, and concentration of FeSO4 solution were optimised by Taguchi design. Moreover, important effective parameters on the adsorption efficiency; such as adsorbent dosage, pH, contact time, and temperature were investigated. The prepared magnetic nanocomposite was applied as a nanocarrier for imatinib mesylate delivery. In vitro studies confirmed imatinib mesylate release over 6 h. The nanocarrier showed pH-dependent imatinib mesylate release with higher drug release at simulated cancer fluid (pH = 5.6) compared to neural fluid (pH = 7.4). Moreover, the sorption isotherms and kinetics for the magnetic nanocomposite were fitted into Langmuir and pseudo-second order models, respectively. Based on the thermodynamic results, the adsorption of imatinib mesylate onto the nanoadsorbent was found to be spontaneous and exothermic.

Graft hyper-branched dendrimer onto WS2 nanosheets modified Poly (N-Vinylcaprolactam) as a thermosensitive nanocarrier for Pioglitazone delivery using near-infrared radiation.

In this paper, graft-copolymerization of N-vinylcaprolactam and allylamine onto tungsten disulfide (WS2) in the presence of AIBN as initiator has been carried out to prepare the WS2@ (NVCL-co-AAm). Subsequent fifth-generation dendrimer was attached to their surface, and used as a nanocarrier for the pioglitazone (PG) drug delivery. The resulting polymer was characterized by FTIR, XRD, TEM, EDX, and TGA. We loaded PG onto polymer and evaluated the drug loading and release patterns in simulated human blood fluid (pH 7.4) for the treatment of diabetes in vitro. The thermosensitive nanocarrier indicated a maximum of 98 % PG release in the simulated human blood fluid at 50 °C within 6 h, and about 18 % of total PG was released from the nanocarrier within 6 h at 37 °C. Herein, we studied near-infrared (NIR) radiation as an irritant for inducing PG release from nanocarrier. Also, PG releasing was 100 % under NIR laser irradiation within 15 min, which was roughly four times of that without laser irradiation. NIR laser light heated the nanocarrier, causing shrinkage of the polymer, which increased the penetrability of the membrane and resulted in PG release. Following four adsorption isotherm models, the Langmuir model excellently explained the adsorption isotherm.

NIPAM/PEG/ MoS2 Nanosheets for Dual Triggered Doxorubicin Release and Combined Chemo-photothermal Cancer Therapy.

INTRODUCTION: Among different 2-D nanostructures, molybdenum disulfide (MoS2) has shown great potential as a good candidate in drug delivery systems. However, their biocompatibility and water dispersibility are the main issues for these purposes. With the aim of improving the MoS2 dispersibility, a novel drug delivery system based on polymer-modified MoS2 nanosheets was successfully prepared and characterized. METHODS: In this study, MoS2 nanosheets were prepared using a simple oleum treatment exfoliation approach and then modified by grafting thermos-responsive polymer N- isopropylacrylamide (NIPAM) and polyethylene glycol (PEG). The structural and morphological properties of the MoS2/NIPAM/ PEG nanosheets were characterized via Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier- Transform Infrared Spectroscopy (FTIR), and Thermogravimetric analysis (TGA/DSC). Initially, the adsorption behavior of the grafted nanoadsorbent was assessed for sorption of doxorubicin as an anticancer drug model. The influence of various parameters such as pH, temperature, and contact time was evaluated. Different kinetic and isotherm models were employed to investigate the (DOX) adsorption mechanism. RESULTS: The obtained results revealed that the DOX adsorption onto the MoS2/NIPAM/ PEG followed the Langmuir isotherm and pseudo-second-order models. In the next step, polymer grafted MoS2 nanosheets were used as thermos-sensitive drug nanocarriers for near-infrared (NIR) photothermal therapy. The combination of chemotherapy and photothermal therapy was also investigated, which indicated a remarkable improvement of cell apoptotic rate compared to monotherapy. Also, MTT assays showed that the MoS2/NIPAM/ PEG had high biocompatibility. CONCLUSION: The novel thermo-responsive MoS2/NIPAM/ PEG showed great potential for targeted and controlled drug delivery.

Application of polyamide thin-film composite layered on polysulfone-GO/TiO2 mixed matrix membranes for removal of nitrotoluene derivatives from petrochemical wastewaters.

Release of harmful organic intermediates or byproducts during the manufacture of petrochemical compounds is a serious problem in petrochemical plants. In this work, polysulfone membranes blended with GO/TiO2 nanocomposite were synthesized by phase inversion method and coated with a polyamide layer formed by interfacial polymerization to prepare a thin-film composite (TFC) sample. Analysis and characterization of the sample were carried out by XRD, FE-SEM, BET, FTIR/ATR, AFM, TGA, and zeta potential. Results indicated that incorporation of GO/TiO2 into the membrane structure enhanced porosity, surface roughness, and macrovoid formation along the cross-section of the sublayer and permeability of the membrane. The TFC membranes were applied to remove mononitrotoluene (MNT) and dinitrotoluene (DNT) as the basic intermediates of toluene diisocyanate (TDI). The membranes demonstrated high efficiency (> 90%) for the removal of MNT and DNT according to the charge exclusion mechanism and Donnan effect. Application of the TFC membrane for treatment of wastewater in the TDI plant showed that the removal of pollutants is variable in the range of 45-65% and 53-69% for the membrane with the highest flux and highest rejection in different transmembrane pressure, respectively.

Removal of Hg2+ by carboxyl-terminated hyperbranched poly(amidoamine) dendrimers grafted superparamagnetic nanoparticles as an efficient adsorbent.

In this research, carboxyl-terminated hyperbranched poly(amidoamine) dendrimers grafted superparamagnetic nanoparticles (CT-HPMNPs) with core-shell structure were synthesized by the chemical co-precipitation method, the core of superparamagnetic iron oxide nanoparticles and a shell of polyamidoamines (PAMAM) and carboxyl groups, as a novel adsorbent for removing Hg2+ from aqueous systems. The surface of the particles was modified by 3-(aminopropyl) triethoxysilane, and finally, PAMAM and carboxyl dendrimers were grown on the surface up to 5.5 generation. The synthesized polymer was characterized physically and morphologically using different techniques. Also, they were evaluated in terms of adsorption capacity to remove inorganic pollutants of Hg2+, selectivity, and reusability. The adsorption mechanism Hg2+ onto CT-HPMNPs was investigated by single-step and two-step isotherms that the adsorption capacity of Hg2+ obtained 72.3 and 32.88 mg g-1 respectively at pH 5, adsorbent dosage 2 g L-1, Hg2+ initial concentrations 20 mg L-1, contact time 60 min, and temperature of 298 K by CT-HPMNPs. Also, the kinetics of Hg2+ followed the pseudo-second-order model and adsorption isotherms of Hg2+ onto CT-HPMNPs were fitted well by Freundlich (as a single-step) and two-step adsorption models with a correlation coefficient of 0.9997 and 0.9999 respectively. The results showed a significant potential of Hg2+ ions removing from industrial wastewater and spiked water by CT-HPMNPs.

Laser irradiation for controlling size of TiO2-Zeolite nanocomposite in removal of 2,4-dichlorophenoxyacetic acid herbicide.

This study focused on the synthesis of TiO2-Zeolite nanocomposite through a sol-gel approach. The decrease in the size of the nanocomposite is considered a primary parameter to improve photocatalytic activity. In this regard, fabricated samples were exposed to laser irradiation (532 nm) for four different time intervals in order to investigate the size variation of the nanocomposite. FTIR, UV-Vis, XRD, DLS, SEM and EDX analyses were applied to characterize and determine the size of the products. An optimized nanocomposite sample, in term of the particle size, was used for photodegradation of 2,4-D herbicide from aqueous solution. Photodegradation was carried out under UV irradiation (12 W) and Xe lamp irradiation (200 W). The obtained results showed that laser irradiation time has a substantial effect on controlling the size of the nanocomposite. Results from the photocatalyst study indicated that the elimination of 2,4-D under the Xe lamp irradiation was higher compared with the UV irradiation. Also, the final synthesized nanocomposite exhibited higher catalytic activity for photodegradation of 2,4-D compared with pure Zeolite and pure anatase TiO2 samples. The reusability of TiO2-Zeolite nanocomposite was studied in four successive cycles to evaluate the removal of 2,4-D under UV irradiation.

Magnetic nanoparticles modified with organic dendrimers containing methyl methacrylate and ethylene diamine for the microextraction of rosuvastatin.

Magnetic nanoparticles (MNPs) modified with organic dendrimers are shown to be a viable sorbent of the microextraction of the drug rosuvastatin (RST; also known as Crestor). The MNPs were prepared from iron(II) chloride and iron(III) chloride and then coated with silicon dioxide. The coated MNPs produced by this method have diameters ranging from 10 to 60 nm according to scanning electron microscopy. The MNPs were further modified with organic dendrimers containing methyl methacrylate and ethylene diamine. The resulting MNPs were characterized by SEM, Fourier transform infra-red and thermal gravimetry analysis. Then, the efficacy of the modified MNPs with respect to the extraction of RST was studied. The adsorption of RST by MNPs can be best described by a Langmuir isotherm. Following elution with buffer, RST was quantified by HPLC. The method was applied to the determination of RST in (spiked) human blood plasma, urine, and in tablets. RST extraction efficiencies are 54.5% in plasma, 86.6% from the drug matrix, and 94.3% in urine. The highest adsorption capacity of the RST by the MNPs adsorbent was 61 mg⋅g-1. Graphical abstract Co-precipitation was used to synthesize magnetic nanoparticles (MNPs). They were coated with a layer of SiO2 and then branched by organic dendrimers containing methyl methacrylate (MMA) and ethylene diamine (EDA). Rosuvastatin (RST) drug was trapped between dendrimer branches, therefore adsorption capacity of the drug was strongly increased.

Synthesis of high generation thermo-sensitive dendrimers for extraction of rivaroxaban from human fluid and pharmaceutic samples.

In this present study, poly (N-isopropylacrylamide) as a thermo-sensitive agent was grafted onto magnetic nanoparticles, then ethylenediamine and methylmethacrylate were used to synthesize the first generation of poly amidoamine (PAMAM) dendrimers successively and the process continued alternatively until the ten generations of dendrimers. The synthesized nanocomposite was investigated using Fourier transform infrared spectrometry, thermalgravimetry analysis, X-ray diffractometry, elemental analysis and vibrating-sample magnetometer. The particle size and morphology were characterized using dynamic light scattering, field emission scanning electron microscopy and transmission electron microscopy. Batch experiments were conducted to investigate the parameters affecting adsorption and desorption of rivaroxaban by synthesized nanocomposite. The maximum sorption of rivaroxaban by the synthesized nanocomposite was obtained at pH of 8. The resulting grafted magnetic nanoparticle dendrimers were applied for extraction of rivaroxaban from biologic human liquids and medicinal samples. The specifications of rivaroxaban sorbed by a magnetic nanoparticle dendrimer showed good accessibility and high capacity of the active sites within the dendrimers. Urine and drug matrix extraction recoveries of more than 92.5 and 99.8 were obtained, respectively.

Efficient removal of cadmium (II) ions from aqueous solution by CoFe2O4/chitosan and NiFe2O4/chitosan composites as adsorbents.

Magnetically recoverable chitosan based spinel cobalt and nickel ferrite (CS/CoFe2O4 and CS/NiFe2O4, respectively) composites were successfully prepared in one step. A series of batch adsorption experiments indicated that the removal of toxic Cd(II) ions by the as-obtained composites as adsorbents was pH-dependent, rapid, proficient, better fitted to pseudo-second-order kinetics model and Langmuir monolayer adsorption isotherm model. Compared to the naked particles, magnetic bio-polymer composites exhibited promoted adsorption capacity. Competitive adsorption studies in binary solutions illustrated preferable selectivity of adsorbents toward Cd(II) ions in the presence of co-existing cations. More importantly, CS/CoFe2O4 and CS/NiFe2O4 had a satisfactory practical application in the removal of Cd(II) from real groundwater spiked with cadmium. The exhausted adsorbents could be regenerated efficiently by 0.5 M HNO3. The results from this study support that CS/CoFe2O4 and CS/NiFe2O4 prove excellent adsorption behavior for the removal of Cd(II) ions from aqueous media.

Study on non-linear equilibrium, kinetics and thermodynamic of deltamethrin removal in aqueous solution using modified magnetic iron oxide nanoparticles.

The purpose of modification of magnetic iron oxide nanoparticles is an eco-friendly, emerging and economical method for removing deltamethrin in the aqueous solution and wastewater effluents when compared with other adsorbent methods. Modified magnetic iron oxide nanoparticles were synthesized by co-precipitation and then coupled with 3-hydroxytyraminium chloride. The nano-sorbent was characterized by thermogravimetric analysis, elemental analysis, transmission electron microscopy, scanning electron microscope, Fourier transform infrared spectroscopy, zero point charge and surface area determination. Batch studies were conducted and adsorption equilibrium, kinetic and thermodynamic non-linear models were carried out. The resulting equilibrium data were tested with Langmuir and Freundlich non-linear isotherm models, and the results showed that the Langmuir isotherm fitted the data well. Kinetic studies were done with different initial deltamethrin concentrations, adsorbent dosage and temperature, and the data were assimilated with pseudo-first order, pseudo-second order and intra-particle diffusion kinetic equations, and it was found that the studied nano-sorbent processes followed the pseudo-second order kinetic equation. Thermodynamic analysis was also carried out to estimate the changes in free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0). The thermodynamic parameters revealed that the adsorption of deltamethrin into the nano-sorbent was spontaneous, feasible and showed an endothermic process.

Functionalized superparamagnetic nanoparticles with a polymer containing ß-cyclodextrin for the extraction of sertraline hydrochloride in biological samples.

In this study, a novel magnetic nanoadsorbent was synthesized by grafting ß-cyclodextrin onto the modified surface of Fe3 O4 nanoparticles for the sorption and extraction of sertraline hydrochloride from human biological fluids. The extracted sertraline hydrochloride was measured by high-performance liquid chromatography. The grafted nanosorbent was confirmed by Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, and elemental analysis. The kinetic sorption of sertraline hydrochloride by magnetic nanosorbent was 1 h. The best temperature for sorption of sertraline hydrochloride was at 25°C at an optimum pH of 5. The adsorbed sertraline hydrochloride can be desorbed by using methanol solution containing acetic acid (5%) and trifluoroacetic acid (1%).

Preparation of functionalized graphene oxide and its application as a nanoadsorbent for Hg(2+) removal from aqueous solution.

A poly(allyl acetoacetate)-grafted graphene oxide (GO-GAA) was successfully synthesized using Hummer's method by divinyl sulfone modification and allyl acetoacetate polymerizaton. This novel functionalized graphene oxide was characterized thoroughly by FTIR, XRD, FE-SEM, TEM, and TG-DT analyses. GO-GAA was then employed as an adsorbent for Hg(2+) removal from aqueous solutions. It exhibited higher adsorption capacity with regard to the pristine graphene oxide because of its effective functionalities, especially the dicarbonyl groups which are significant chelating agents. The effects of pH, temperature, and contact time on Hg(2+) adsorption were also investigated. The optimum Hg(2+) adsorption was obtained at pH 4 and T = 20-30 °C. The adsorption isotherm and kinetics were found to follow the Langmuir and pseudo-second-order models, respectively, with a correlation coefficient of 0.99 for both. The calculated maximum adsorption capacity of the adsorbent was 282.7 mg Hg(2+) per unit mass of GO-GAA, which is much more than 56 mg/g of that obtained for GO. The results showed that adsorption reaches up to 95 % of its maximum in less than 2 min. The synthesized GO-GAA as a novel and efficient adsorbent has been regenerated by HNO3 and reused. It retained its performance for Hg(2+) removal for several times and a less than 5 % decrease in removal efficiency was observed after four cycles of adsorption-desorption.

Preconcentration and Determination of Mefenamic Acid in Pharmaceutical and Biological Fluid Samples by Polymer-grafted Silica Gel Solid-phase Extraction Following High Performance Liquid Chromatography.

Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that has analgesic, anti-infammatory and antipyretic actions. It is used to relieve mild to moderate pains. Solid-phase extraction of mefenamic acid by a polymer grafted to silica gel is reported. Poly allyl glycidyl ether/iminodiacetic acid-co-N, N-dimethylacrylamide was synthesized and grafted to silica gel and was used as an adsorbent for extraction of trace mefenamic acid in pharmaceutical and biological samples. Different factors affecting the extraction method were investigated and optimum conditions were obtained. The optimum pH value for sorption of mefenamic acid was 4.0. The sorption capacity of grafted adsorbent was 7.0 mg/g. The best eluent solvent was found to be trifluoroacetic acid-acetic acid in methanol with a recovery of 99.6%. The equilibrium adsorption data of mefenamic acid by grafted silica gel was analyzed by Langmuir model. The conformation of obtained data to Langmuir isotherm model reveals the homogeneous binding sites of grafted silica gel surface. Kinetic study of the mefenamic acid sorption by grafted silica gel indicates the good accessibility of the active sites in the grafted polymer. The sorption rate of the investigated mefenamic acid on the grafted silica gel was less than 5 min. This novel synthesized adsorbent can be successfully applied for the extraction of trace mefenamic acid in human plasma, urine and pharmaceutical samples.

Selective Solid-Phase Extraction of Zinc(II) from Environmental Water Samples Using Ion Imprinted Activated Carbon.

A simple ion imprinted amino-functionalized sorbent was synthesized by coupling activated carbon with iminodiacetic acid, a functional compound for metal chelating, through cyanoric chloride spacer. The resulting sorbent has been characterized using FTIR spectroscopy, elemental analysis, and thermogravimetric analysis and evaluated for the preconcentration and determination of trace Zn(II) in environmental water samples. The optimum pH value for sorption of the metal ion was 6-7.5. The sorption capacity of the functionalized sorbent was 66.6 mg/g. The chelating sorbent can be reused for 10 cycles of sorption-desorption without any significant change in sorption capacity. A recovery of 100% was obtained for the metal ion with 0.5 M nitric acid as the eluent. Compared with nonimprinted polymer particles, the prepared Zn-imprinted sorbent showed high adsorption capacity, significant selectivity, and good site accessibility for Zn(II). Scatchard analysis revealed that the homogeneous binding sites were formed in the polymer. The equilibrium sorption data of Zn(II) by modified resin were analyzed by Langmuir, Freundlich, Temkin, and Redlich-Peterson models. Based on equilibrium adsorption data, the Langmuir, Freundlich, and Temkin constants were determined as 0.139, 12.82, and 2.34, respectively, at 25°C.

Synthesis and characterization of poly[N-isopropylacrylamide-co-1-(N,N-bis-carboxymethyl)amino-3-allylglycerol] grafted to magnetic nano-particles for the extraction and determination of fluvoxamine in biological and pharmaceutical samples.

In this research, a novel method is reported for the surface grafting of N-isopropylacrylamide as a thermosensitive agent and 1-(N,N-bis-carboxymethyl)amino-3-allylglycerol with an affinity toward fluvoxamine onto magnetic nano-particles modified by 3-mercaptopropyltrimethoxysilane. The grafted nano-particles were characterized by Fourier transform infrared spectroscopy, elemental analysis, and thermogravimetric analysis. The surface morphology was studied with scanning electron microscopy and transmission electron microscopy. The resulting grafted nano-particles were used in solid phase extraction and determining of trace fluvoxamine in biological human fluids and pharmaceutical samples. The profile of the fluvoxamine uptake by the modified magnetic nano-particles indicated good accessibility of the active sites in the grafted copolymer. It was found that the adsorption behavior could be fitted by the Freundlich adsorption isotherm model. It was observed that a maximum amount of fluvoxamine was released at a temperature above the lower critical solution temperature of the polymer.

Selective extraction of clonazepam from human plasma and urine samples by molecularly imprinted polymeric beads.

A molecularly imprinted polymer (MIP) based on free-radical polymerization was prepared with 1-(N,N-biscarboxymethyl)amino-3-allylglycerol and N,N-dimethylacrylamide as functional monomers, N,N-methylene diacrylamide as the cross-linker, copper ion-clonazepam as the template and 2,2-azobis(2-methylbutyronitrile) as the initiator. The imprinted polymer was characterized by Fourier transform infrared spectroscopy, elemental analysis, thermo-gravimetric analysis, and SEM. The MIP of agglomerated microparticles with multipores was used for SPE. The imprinted polymer sorbent was selective for clonazepam. The optimum pH and sorption capacity were 5 and 0.18 mg/g at 20C, respectively. The profile of the drug uptake by the sorbent reflects good accessibility of the active sites in the imprinted polymer sorbent. The MIP-SPE was the most feasible technique for the extraction of clonazepam with a high recovery from human plasma and urine samples.