Mg Of Polymer Research Articles

A Cyanoalkyl Silicone GC Stationary-Phase Polymer as an Extractant for Dispersive Liquid–Liquid Microextraction

In this work, three cyanoalkyl silicone GC stationary-phase polymers, namely OV-105, OV-225, and OV-275, were investigated as potential extractants for dispersive liquid–liquid microextraction (DLLME). The OV-225 polymer (cyanopropylmethyl-phenylmethylsilicone) exhibited the cleanest chromatographic background and was extensively studied. The proposed polymer was tested through the DLLME of four non-steroidal anti-inflammatory drugs from aqueous samples, followed by HPLC separation with UV detection at 230 nm. To achieve the maximum enrichment, the experimental conditions that influence the DLLME process were optimized using one-factor-at-a-time and design-of-experiment (DoE) approaches. The extraction variables (polymer mass, dispersive solvent volume, buffer pH, and mixing time) were screened by implementing a two-level full factorial design (FFD). Significant variables were fine-tuned using response surface methodology based on a face-centered central composite design (CCD). The optimum conditions were 10 mg of polymer (extraction medium); 50 µL of tetrahydrofuran (dispersive solvent); 100 µL of phosphate buffer pH 2.75 ([PO43−] = 100 mM); and 3 min of vortex mixing. The addition of salt had a minimal effect on the enrichment factors. In the optimum conditions, enrichment factors up to 46 were achieved using 1.5 mL samples. Calibration curves exhibited correlation coefficients > 0.999 using 4-pentylbenzoic acid as an internal standard. The limits of quantitation were 5 ng/mL for naproxen, 10 ng/mL for diflunisal, 25 ng/mL for indomethacin, and 75 ng/mL for ibuprofen. The analysis of spiked tap water samples showed adequate relative recoveries and precision. In conclusion, the proposed polymer (OV-225) is a potential greener alternative to traditional organic extractants used in DLLME.

Treatment of Turbid Water Collected from Oil Mill Waste (OMW) Using Low Content of Gum Arabic polymer (GA)

Using synthetic polymers in clarifying of turbid wastewater is a very expensive method, in addition to their monomers toxicity produced from the polymerisation reaction. Those drawbacks encouraged several scientists who were interested in eco-friendly sustainable materials to discover an upright replacement to clarify turbid wastewater. The present study introduces Gum Arabic (GA) as a health-friendly natural polymer flocculant, which could be applied in the pre-filtration process of oil mill wastewaters (OMWW) treatment. GA-silica as a model work and GA-OMWW interaction was investigated experimentally by turbidimetric technique and mathematically by GraphPad Prism® software, since plateau followed by one phase decay was a good fit at adding 1250 and 12500 mg of polymer, while one phase decay was selected as a proper fit for 12.5 and 125 mg. Results supposed that the biopolymer improves markedly the sedimentation performance of suspended materials. Digital micrographs agreed with the turbidity results.

Novel ferrocene-containing amphiphilic block copolymer nanoparticles as high-capacity charge carriers in aqueous redox flow systems

Size-exclusion polymer electrolytes are promising charge carriers to diminish the crossover and allowing commercially available low-cost porous membranes in redox flow batteries. Boosting the solubility in water and maximizing the number of redox sites to enhance the capacity of these polymeric systems is challenging. New highly water dispersed amphiphilic diblock copolymers are reported here, with an average concentration value of 1.7 10−3 mmol of Ferrocene (Fc)-linked moieties per mg of polymer, determined by total X-ray reflection fluorescence. These redox amphiphilic block copolymers are stabilized in water as spherical nanoparticles (20 nm) by using a simple phase solvent inversion procedure. We evidence a maximum polymer dispersibility value of 6 g/L in water, for long-term stable polymer nanoparticle suspensions, yielding a theoretical capacity value of 4.78 mAh at 10.5 mM Fc. Further adjustment of the ionic conductivity and pH of these stable redox block copolymer suspensions has rendered a conductivity value of 44.5 mS/cm at pH values close to a neutral one, by adding a variety of salt supports. Studies using a 3-electrode configuration cell reveal an efficient charge transport between each of the Fc motifs in the polymer nanoparticle. A capacity value of 3.1 mAh with no transient of the polymer nanoparticles crosswise the cheap porous membrane is evidenced when cycled as polycatholyte material in a Zn hybrid aqueous redox flow battery. The particle size and electronic changes of these novel amphiphilic redox block copolymer electrolytes during consecutive redox cycles have also been monitored by dynamic light scattering and ultraviolet-visible spectroscopy, respectively. The analysis of the results enables the understanding of the main mechanisms behind their non-fully reversible capacity. Among them, aggregation and sedimentation, along with retention inside the graphite felt electrode acting the latter as a filter. These insights will aid the design of future polymer electrolyte materials and redox flow battery components with better performance and cost.

Selective Solid-Phase Extraction of Meropenem from Human Blood Plasma Using a Molecularly Imprinted Polymer

This study employed a selective and high adsorption performance for meropenem. Molecularly imprinted polymer for meropenem (MeIP) as the selective sorbent was prepared through a bulk polymerization reaction. Methacrylic acid, ethylene glycol dimethacrylate, benzoyl peroxide, and dimethyl sulfoxide were applied as functional monomer, crosslinker agent, initiator, and solvent, respectively. Scanning electron microscopy, thermogravimetric analysis, Brunauer-Emmett-Teller analysis, and Fourier transform infrared spectroscopy were used to characterize the morphology, pore size, and structure of imprinted polymers. The maximum adsorption capacity was achieved at pH = 3, after 4 h contacted, under 150 rpm, and 25 mg of polymer applied. The maximum adsorption capacity of MeIP for meropenem was 51.963 mg/L; the synthesized polymer had superior selectivity to meropenem compared to that of the other antibiotics (imprinting factor, IF = 2.58). Furthermore, the thermodynamic and kinetic analyses indicated that the results were in accord with the Freundlich model and the pseudo-second-order kinetic model, respectively. MeIP was selective in batch adsorption, and molecularly imprinted solid-phase extraction protocols were selective to meropenem. It was then applied to analyze meropenem in human blood plasma and resulted in 78.52 ± 2.71 of recovery.

A Game Changer in Scale-Squeeze Technology

Background Field trials using a new scale-inhibitor technology that improves treatment lifetime of scale squeezes have been successfully performed in the Gulf of Mexico. Tomson Technologies, in partnership with Shell, developed proprietary nanoparticle carriers that enhance scale-inhibitor adsorption to the reservoir and control the return rate for extended periods of time. This technology results in less chemical bleed off in the initial flowback and increases the chemical retained in the reservoir, allowing for more effective squeeze treatments. Both nanoparticle-enabled phosphonate and polymer inhibitors have now been developed and successfully squeezed in the field. Phosphonate inhibitors are widely used for squeeze treatment due to their desirable adsorption and release properties in carbonate and sandstone reservoirs. Minor changes have been made to the chemistry, but overall, the fundamentals have remained unchanged for decades. Polymeric scale inhibitors have also been developed for cases in which phosphonates are not applicable. The nano-enhanced technology provides a large improvement of treatment lifetime of 2 to 4 times (200-400%) when compared to incumbents, making this technology advancement attractive even in cases where current squeezes are considered successful. The well selected for this case study is an offshore formation with a predominantly sandstone mineralogy (approximately 80% quartz) with 25-30% porosity and bottomhole temperature of 183°F (83°C). Technology From the Lab to Field A sandpack sample from the trial well was used in the laboratory to deter-mine the adsorption and desorption properties of the nano-enabled inhibitor in realistic rock conditions. Multiple conditioning steps were used before product was injected in a sequence that mimicked field squeeze treatments. Mass-balance results from the sandpack experiment show adsorption of approximately 8 mg of polymer retained per gram of crushed reservoir rock used in the experiment. A typical rule of thumb for phosphonate-scale inhibitors (only as a comparison since this is a polymeric scale inhibitor) is 1-2 mg of inhibitor retained per gram of rock. Therefore, this is considered a large improvement on adsorption. There are challenges associated with measuring polymers in brine as residuals; however, multiple methods, both in-house and external, were com-pared to ensure accuracy. The results using the nano-enhanced scale inhibitor show concentrations higher than 1 mg/L of active polymer for over 7,000 pore volume of return in the sandpack experiment. Complete intact core experiments were also conducted with reservoir fluids and showed no formation damage during the injection of the product with regained oil permeability of 96%. Oil permeability was in the 150-200 mD range for the intact core experiments. Third-party coreflood testing was performed with nitrified and foamed stages to ensure compatibility with the nano-enabled chemistry. No formation damage was observed with the nitrification of the stages containing the nano-enabled chemistry. Field Application Case Study After extensive lab validation of the product and supporting corefloods to de-risk the technology, Well A was selected by Shell to be the first well treated with the new nano-enabled extended-lifetime inhibitor.

Design, statistical optimization of Nizatidine floating tablets using natural polymer

BackgroundThe present research was aimed in developing gastroretentive tablets of Nizatidine, in order to increase the bioavailability of the drug. Nizatidine belongs to BCS class 3 and thus formulating into gastroretentive tablets helps to achieve a better therapeutic effect. There were no reports available on the use of Mimosa gum in the design of gastroretentive drug delivery systems. Response surface methodology was employed to optimize the formulation with suitable experimental design. The goal of the response surface methodology was to obtain a regression model and to find a suitable approximation for the true functional relationship between the response and the set of independent variables. Hence, the statistical approach like full factorial design was utilized to obtain optimized formulation with a smaller number of experiments.ResultsDSC study justified no interaction of the drug with excipients. The floating lag time was observed to be less than 20 s, total floating time was in the range of 8–24 h, hardness ranges from 4 to 5 kg/cm2, and friability was less than 1%. Dissolution data indicated that the higher viscosity of Mimosa (2%) delayed the drug release for extended period of time up to 23 h when compared to lower viscosity Mimosa (1%), which controlled the release of the drug up to 12 h only. The ‘n’ values of all the prepared formulations were found to be 0.59 to 0.81 indicating that the release mechanism followed anomalous (non-Fickian) diffusion. The optimal values of independent test variables were obtained from the overlay plots. The optimized formulation of Mimosa gum (2%) (M2%opt) contained 170 mg of polymer and 25.5 mg (15%) of sodium bicarbonate. Similarly, the optimized formulation of Mimosa (1%) (M1%opt) contained 255 mg of polymer and 34 mg (10%) of sodium bicarbonate.ConclusionThe results clearly indicated that the optimized formulations followed zero-order release kinetics with diffusion mechanism as per the predicted theoretical release rate confirming the suitability of the predicted theoretical release profile.

AB0175 INNOVATIVE PREPARATION OF CURCUMIN NANOPARTICLES TO IMPROVE ANTI-INFLAMMATORY EFFECT IN RHEUMATIC DISEASE

Background:Curcumin (Cur) as a natural compound can be used in the wide spectrum of healthy functions and pharmacological activities [1-4]. It shows great promise for medication of various pro-inflammatory chronic illnesses [5]. In this study, we evaluate the ability of poly(lactide-co-glycolide)(PLGA) and different grads of PVA (polyvinyl alcohol) and lecithin as a drug delivery system for poorly soluble CurObjectives:The goal of this study was to prepare and characterize Cur encapsulated PLGA and different grads of PVA and lecithin as an efficient nanocarrier for improve anti-inflammatory effect in rheumatic diseaseMethods:The PLGA nanospheres were formulated and then characterized for percent yield, encapsulation efficiency, surface morphology, and in vitro drug release profiles. At first, 6 mg of Cur was added to the organic phase including 24 mg of polymer dissolved in 5 mL of dichloromethane to constitute 1:4 (drug-to-polymer) ratios. Then, a mixture of PVA-lecithin (at about 5 cc) was added to maintain the stability of double emulsion droplets. The emulsion was continuously stirred at 300 rpm for 24 hours (at temperature of 37.5 ˚C) to evaporate the solvent, leaving behind the colloidal suspension of the drug-encapsulated nanoparticle in aqueous phase. The encapsulation of Cur into PLGA was characterized by Fourier transform infrared spectroscopy (FT-IR) and Transmission electron microscopy (TEM).Results:Our studies achieved the successful formation of smooth surface and spherical shape Cur encapsulated into PLGA nanoparticles by the TEM image confirmed. The particle size distribution demonstrated a range of 30 nm to 100 nm, with the mean particle size being 45 nm. FTIR study implies successful loading of Cur into the nanoparticles. We show high drug-loading efficiency about 98 ± 0.5% for 6% of Cur weight in total ingredients weight of PLGA (w/w). It was also seen that a slower sustained release of 10% CUR in 48 hours is observed with biocompatible PLGA in phosphate buffered saline (pH = 7.4). The MTT assay of the Cur-PLGA exhibited no cytotoxic effect on Normal mouse fibroblast cells (L-929) cell line. IC50 of Cur -PLGA increased 99.5% against Cur nanoparticles (33.57 ±0.62 µM) (P < 0.05).Conclusion:In this study, we constructed a novel preparation of curcumin nanoparticles with PLGA and different grads of PVA (polyvinyl alcohol) and lecithin to improve the bioavailability of CUR and PLGA exhibited no cytotoxic effect on L-929 cell line

Synthesis of Diazepam-Imprinted Polymers with Two Functional Monomers in Chloroform Using a Bulk Polymerization Method

Diazepam is a benzodiazepine that has the potency to be misused because it is effective, easily obtained, and inexpensive. The misuse of diazepam is to replace illegal drugs and be a sedative. Separation of diazepam is needed to detect possible drug abuse and to monitor drug levels in blood to ensure the effectiveness of the drug. This study was conducted to obtain a molecularly imprinted solid-phase extraction (MI-SPE) sorbent to separate diazepam from serum samples. This work started at the synthesis stage with the bulk polymerization method, using methyl methacrylate and acrylamide as functional monomers, diazepam as a template, and ethylene glycol dimethacrylate as a crosslinker. The polymer obtained was identified by its adsorption capacity and packaged into a solid-phase extraction (SPE) cartridge, and the extraction conditions were optimized. The optimization results were then used to extract diazepam from the serum sample. The test results showed that the adsorption ability of the molecularly imprinted polymer (MIP) with the functional monomer, methyl methacrylate, was 63.98 ± 0.1%, which is higher than that of the acrylamide MIP monomer, with a value of 43.27 ± 0.1%. The MIP sorbent of methyl methacrylate was applied to the SPE with 200 mg of polymer in a 3 mL cartridge. Diazepam added to serum samples were then passed through the MIP-SPE producing a percent recovery value of 95.31 ± 1.1% for MIP and 60.83 ± 0.3% for nonimprinted polymer (NIP). The results showed that the MI-SPE sorbent made from the monomer methyl methacrylate gave higher extraction recovery results than acrylamide, and it could be used for extracting diazepam from serum samples with or without other substances.

Formulation and Evaluation of Mesalamine Nanosphere Tablet

Nanospheres are the particles having the size range between 10-200 nm in diameter. Nanospheres can be amorphous or crystalline in nature and also they have the ability to protect the drug from enzymatic and chemical degradation. For the preparation of standard calibration curve of Mesalamine with Phosphate buffer pH 6.8 and Absorbance of µg/ml solution was measured between 200-400nm by using Shimadzu 1601 UV/Vis double beam spectrophotometer. Nanosphare containing Mesalamine were prepared using nanoprecipitation method. 200 mg of polymer (Eudragit RS and L) was dissolve in 50 ml water. Drug was dissolve in 20 ml of methanol. Both solution were mixed and add 50 ml of water and stirred for half an hour. Methanol and water was evaporated under reduced pressure using rotary flash evaporator until 10 ml of solution was remaining. Than this suspension was centrifuge at 15000 rpm at 40C for half an hour. The supernatant was discarded and remaining portion was washed with distilled water. The nano-sphares was dried over night at 600C and stored in desiccators. The surface morphology (roundness, smoothness, and formation of aggregates) and particle size was studied by scanning electron microscopy (SEM). Zeta potential of the best formulation (F4) was determined by zeta potential probe model DT- 300. Mesalamimne, Dextrose and Lactose were taken in required quantities mixed and granulating agent (Starch past) was added and passed through #40 sieves, then lubricant magnesium stearate and talc was added then compressed into tablets by rotary tablet punching machine. Then film coating is done by 6% w/v solution of Cellulose acetate Phthalate in isopropyl alcohol using 2% tween-80 as plasticizer in coating pan. The weight of tablet was kept constant for all formulations. Nanosphare tablet formulation F-2 Showed maximum drug (97.75%) released and formulation F-4 showed 92.58% drug release. The In-vitro drug released study result showed that formulation F-2 96.58% drug was released after 17 hours which is highest drug release amongst all other tablet formulation.

Oral Insulin Delivery in Diabetic Rats by PLGA Nanoparticles Combined with a Protease Inhibitor (N-Ethylmaleimide)

Nanoparticles have shown a certain potential to overcome thedrawbacks of oral peptide delivery in the gastrointestinal tract such as lowpeptide stability and permeability. Insulin PLGA NP were prepared using amodified double emulsion solvent evaporation technique. Insulin PLGA NP were composedfrom human insulin (5 mg) encapsulated in PLGA 2.5% (w/v) mixed with PEG (2kDa, 5% w/w) and the external aqueous phase contained 1.25% of PVA. Theresulting nanoparticles of 202.6 nm diameter and loaded with 33.86 μg insulinper mg of polymer were utilised in this study to examine the hypoglycaemiceffect after combination with a protease inhibitor, N-Ethylmaleimide.

Dapivirine Bioadhesive Vaginal Tablets Based on Natural Polymers for the Prevention of Sexual Transmission of HIV.

Young sub-Saharan women are a group that is vulnerable to the sexual transmission of HIV. Pre-exposure prophylaxis through vaginal microbicides could provide them an option for self-protection. Dapivirine has been demonstrated to have topical inhibitory effects in HIV, and to provide protection against the sexual transmission of this virus. This paper reports on the studies into swelling behaviour, bioadhesion and release carried out on dapivirine tablets based on chitosan, locust bean gum and pectin, to select the most suitable formulation. The modified simulated vaginal fluid led to a high solubility of dapivirine and allowed the dapivirine release profiles to be characterized in sink conditions; this aqueous medium is an alternative to organic solvents, which are not a realistic option when evaluating systems whose behaviour varies in aqueous and organic media. Of the formulations evaluated, dapivirine/pectin tablets containing 290 mg of polymer and 30 mg of dapivirine present the most moderate swelling, making them the most comfortable dosage forms. Their high bioadhesive capacity would also allow the formulation to remain in the action zone and release the drug in a sustained manner, pointing to this formulation as the most promising candidate for future evaluations of vaginal microbicides for the prevention of HIV.

(SPION-PLGA) ±PEG nanoparticles loaded with Gemcitabine as a multifunctional nanoparticle for therapeutic and diagnostic applications

Abstract The aim of this study was to develop a novel multifunctional nanoparticle, which encapsulates SPION and Gemcitabine in PLGA±PEG to form multifunctional drug delivery system. For this aim, super paramagnetic iron oxide nanoparticles (SPIONs) were synthesized and encapsulated simultaneously with Gemcitabine (Gem) in PLGA±PEG copolymers via W/O/W double emulsification method. Optimum size and encapsulation efficiency for radiosensitization, hyperthermia and diagnostic applications were considered and the preparation parameters were systematically investigated and physicochemical characteristics of optimized nanoparticle were studied. Then SPION-PLGA and PLGA-Gem nanoparticles were prepared with the same optimized parameters and the toxicity of these nanoparticles was compared with Gemcitabine in human breast cancer cell line (MCF-7). The optimum preparation parameters were obtained with Gem/polymer equal to 0.04, SPION/polymer equal to 0.8 and 1% sucrose per 20 mg of polymer. The hydrodynamic diameters of all nanoparticles were under 200 nm. Encapsulation efficiency was adjusted between 13.2% to 16.1% for Gemcitabine and 48.2% to 50.1% for SPION. In-vitro Gemcitabine release kinetics had controlled behavior. Enhancement ratios for PLGA-Gem and SPION-PLGA-Gem at concentration of nanoparticles equal to IC50 of Gemcitabine were 1.53 and 1.89 respectively. The statistical difference was significant (p-value=0.006 for SPION-PLGA-Gem and p-value=0.015 for PLGA-Gem compared with Gemcitabine). In conclusion, we have successfully developed a Gemcitabine loaded super paramagnetic PLGA- Iron Oxide multifunctional drag delivery system. Future work includes in-vitro and in-vivo investigation of radiosensitization and other application of these nanoparticles.

The Release of Doxorubicin’s Active Ingredient from the Hydrogels with Poly (HEMA/Acrylamide/ Itaconic acid) and Their Biological Function

Abstract: In this study, Poly (HEMA/Acrylamide/ Itaconic acid) (HAI) polymer was synthesized for using in the release of Doxorubicin drug. Poly (HEMA/acrylamide/Itaconic acid) (HAI) hydrogel was prepared by a radical addition reaction in aqueous media formed by HEMA, acrylamide, Itaconic acid, in the presence of TEMED (N,N,N’,N’-tetramethylenediamine). The characterization of the polymer was performed by FTIR analysis. At the same time, swelling and drug absorption capabilities of the polymers were analyzed. It has been observed that the entire drug, which was added to the solution with 0.1 mg of polymer, was absorbed in around 25 hours. This measurement showed that the absorption of this polymer is quite high compared to many polymers in the literature. Moreover, this polymer showed 80% swelling at 1000 minutes. In the light of these results, it has been concluded that this new polymer is very suitable for the release of Doxorubicin drug. Key words: Doxorubicin, Poly (HEMA/acrylamide/Itaconic acid), Drug release, FTIR, kinetix

Preparation, Optimization and Toxicity Evaluation of (SPION-PLGA) ±PEG Nanoparticles Loaded with Gemcitabine as a Multifunctional Nanoparticle for Therapeutic and Diagnostic Applications.

The aim of this study was to develop a novel multifunctional nanoparticle, which encapsulates SPION and Gemcitabine in PLGA ± PEG to form multifunctional drug delivery system. For this aim, super paramagnetic iron oxide nanoparticles (SPIONs) were simultaneously synthesized and encapsulated with Gemcitabine (Gem) in PLGA ± PEG copolymers via W/O/W double emulsification method. Optimum size and encapsulation efficiency for radiosensitization, hyperthermia and diagnostic applications were considered and the preparation parameters systematically were investigated and physicochemical characteristics of optimized nanoparticle were studied. Then SPION-PLGA and PLGA-Gem nanoparticles were prepared with the same optimized parameters and the toxicity of these nanoparticles was compared with Gemcitabine in human breast cancer cell line (MCF-7). The optimum preparation parameters were obtained with Gem/polymer equal to 0.04, SPION/polymer equal to 0.8 and 1% sucrose per 20 mg of polymer. The hydrodynamic diameters of all nanoparticles were under 200 nm. Encapsulation efficiency was adjusted between 13.2% to 16.1% for Gemcitabine and 48.2% to 50.1% for SPION. In-vitro Gemcitabine release kinetics had controlled behavior. Enhancement ratios for PLGA-Gem and SPION-PLGA-Gem at concentration of nanoparticles equal to IC50 of Gemcitabine were 1.53 and 1.89 respectively. The statistical difference was significant (p-value = 0.006 for SPION-PLGA-Gem and p-value = 0.015 for PLGA-Gem compared with Gemcitabine). In conclusion, we have successfully developed a Gemcitabine loaded super paramagnetic PLGA-Iron Oxide multifunctional drag delivery system. Future work includes in-vitro and in-vivo investigation of radiosensitization and other application of these nanoparticles.

FORMULATION DEVELOPMENT, CHARACTERIZATION AND IN- VITRO EVALUATION OF FLOATING MATRIX DOSAGE FORM OF TRAMADOL HYDROCHLORIDE USING VARIOUS POLYMERS

Objective: The purpose of present study was to formulate the gastro retentive floating tablets of tramadol hydrochloride for enhancement of the gastric residence time.Methods: The floating tablets were prepared by direct compression method and evaluated for hardness, thickness, and friability of the tablets. The in vitro drug release studies were performed for different formulations and to optimize the best formulae based on the dissolution profiles.Results: Fourier transform infrared spectroscopy and differential scanning calorimetry studies revealed that there was no interaction between tramodol hydrocholride and excipients. The formulated tablets were evaluated for properties like weight variation, hardness, thickness, friability, drug content, density and floating properties, matrix integrity and complied with USP requirements. The tablets of optimized formula had floating lag time of 120, 72 and 96 seconds and the tablets remained in the floating condition for more than 12 h. The results of drug excipients compatibility studies suggest that there was no significant change in the physical appearance of these blends, when stored at 40 °C/75% RH for a period of 4 weeks. Among various trial formulations developed with different concentration of polymer F3 (HPMC K4 M with 120mg of polymer), F5 (HPMC K15 M with 100 mg polymer), F11 (PEO WSR 303 with 100mg polymer), were chosen as the optimized formulations based on the release profile.Conclusion: Tramodol HCl floating tablets were successfully made using various polymers for the enhancement of the gastric residence time. From the present study it was concluded that hydroxy propyl methyl cellulose K 4 M can be used as effective polymer for the formulation of floating effervescent tablets of highly soluble drug indicating successful development of sustained release floating drug delivery system.Key words: Tramodol HCl, floating tablets, PEO 303 WSR, PEO N60, HPMC K 4 M, HPMC K15 M and HPMC K 100 M.

Enhancement of temozolomide stability by loading in chitosan-carboxylated polylactide-based nanoparticles

In the presented work, amphiphilic nanoparticles based on chitosan and carboxy-enriched polylactic acid have been prepared to improve the stability of the pro-drug temozolomide in physiological media by encapsulation. The carrier, with a diameter in the range of 150–180 nm, was able to accommodate up to 800 μg of temozolomide per mg of polymer. The obtained formulation showed good stability in physiological condition and preparation media up to 1 month. Temozolomide loaded inside the carrier exhibited greater stability than the free drug, in particular in simulated physiological solution at pH 7.4 where the hydrolysis in the inactive metabolite was clearly delayed. CS-SPLA nanoparticles demonstrated a pH-dependent TMZ release kinetics with the opportunity to increase or decrease the rate. Mass spectroscopy, UV-Vis analysis, and in vitro cell tests confirmed the improvement in temozolomide stability and effectiveness when loaded into the polymeric carrier, in comparison with the free drug.

Quercetin-imprinted polymer for anthocyanin extraction from mangosteen pericarp.

Molecular imprinting is a facilitative technology for the production of artificial receptors possessing great endurance with high specificity toward target molecules of interest. The polymers are commonly applied for separation or analysis of substances of interest. In this study, we prepared molecularly imprinted polymers for the purpose of binding specifically to quercetin and related compounds. Quercetin was used as the template molecule, 4-vinylpyridine (4-VP) as the functional monomer, ethylene glycol dimethacrylate (EDMA) as the cross-linking monomer, azobisisobutyronitrile (AIBN) as the polymerization initiator and ethanol as the porogenic solvent. Such 4-VP-based imprinted polymer was found to bind the template molecule greater than that of the control polymer with an approximate 2 folds higher binding using 20mg of polymer in the optimal solvent, ethanol:water (4:1v/v). Quercetin-imprinted polymer (QIP) was found to bind well against its template; approximately 1mg/g polymer. In addition, QIP was applied to bind anthocyanin from the crude extract of mangosteen pericarp. The binding capacity of quercetin-MIP toward anthocyanin was approximately 0.875mg per gram of polymer. This result indicated that quercetin-MIP showed its specific binding to quercetin and related compound particularly anthocyanin. In conclusion, we have demonstrated the successful preparation and utilization of molecularly imprinted polymer for the specific recognition of quercetin as well as structurally related anthocyanins from the mangosteen pericarp with enhanced and robust performance.

Analysis of benzo[a]pyrene in vegetable oils using molecularly imprinted solid phase extraction (MISPE) coupled with enzyme-linked immunosorbent assay (ELISA).

This paper describes the development of a molecularly imprinted polymer-based solid phase extraction (MISPE) method coupled with enzyme-linked immunosorbent assay (ELISA) for determination of the PAH benzo[a]pyrene (B[a]P) in vegetable oils. Different molecularly imprinted polymers (MIPs) were prepared using non-covalent 4-vinylpyridine/divinylbenzene co-polymerization at different ratios and dichloromethane as porogen. Imprinting was done with a template mixture of phenanthrene and pyrene yielding a broad-specific polymer for PAHs with a maximum binding capacity (Q) of ∼32 μg B[a]P per 50 mg of polymer. The vegetable oil/n-hexane mixture (1:1, (v/v)) was pre-extracted with acetonitrile, the solvent evaporated, the residue reconstituted in n-hexane and subjected to MISPE. The successive washing with n-hexane and isopropanol revealed most suitable to remove lipid matrix constituents. After elution of bound PAHs from MISPE column with dichloromethane, the solvent was evaporated, the residue reconstituted with dimethyl sulfoxide and diluted 100-fold with methanol/water (10:90, (v/v)) for analysis of B[a]P equivalents with an ELISA. The B[a]P recovery rates in spiked vegetable oil samples of different fatty acid composition were determined between 63% and 114%. The presence of multiple PAHs in the oil sample, because of MIP selectivity and cross-reactivity of the ELISA, could yield overestimated B[a]P values.

WATER-SOLUBLE CATIONIC CELLULOSE COUPLED TO A ULTRAFILTRATION MEMBRANE FOR THE REMOVAL OF ARSENIC AND CHROMIUM

This article describes the retention properties of arsenic (V) and chromium (VI) using a water-soluble polymer based on cationic hydroxyethylcellulose and combined with an ultrafiltration membrane. The polymer was purchased commercially and was characterized by Fourier transform infrared spectroscopy (FTIR). The study of polymer removal capacity of As(V) and Cr(VI) were performed by liquid-phase polymer-based retention technique (LPR). By means of a washing method studied retention as a function of pH, the amount of polymer, and the concentration of As(V) and Cr(VI). The results showed that the retention capacity of both oxy-anions increases with the solution pH. Due to the presence of quaternary ammonium groups in the polymer structure, the retention of As(V) and Cr(VI) was higher at a pH of 9 than that at acidic pH levels, reaching values of 65% for Cr(VI) and 43% for As(V). The study in function of amount of polymer showed that using 75 mg the retention of As(V) was 65%. In the case of Cr(VI) using 50 mg of polymer, 67% retention was obtained. Using low concentrations for arsenic and chromium, maximum retention was found at 65% and 95%, respectively. The maximum retention capacity (MRC) of the polymer was determined by adding As(V) and Cr(VI) to the polymer solution and concentrating in successive steps. FTIR spectra before and after of retention showed differences by the interaction with oxy-anions.

Unique photoactive nanocomposites based on rhodamine 6G/polymer/montmorillonite hybrid systems

ABSTRACTAn organo‐montmorillonite (MMT) complex [poly‐diallyldimethyl(PDDA)‐Kunipia F] with various loadings of polycation was modified with a laser dye Rhodamine 6G (R6G) to obtain a photofunctional hybrid materials for monitoring of dye‐polymer‐MMT nanocomposite interactions. The polymer‐MMTs were prepared in a colloidal state via ion‐exchange reaction. The content of polycation (PDDA) in suspensions varied from 20 mg to 1000 mg per 1 g of Kunipia F (KF) MMT. Dramatic changes was observed in the structure of PPDA‐MMT containing 200–300 mg of polymer per 1 g of KF, which was the saturation point of the polycation for this system. The PDDA molecules were able to suppress the formation of nonluminescent H‐aggregates and to enhance the overall luminescence properties. The PDDA/MMT nanocomposite systems are the novel ones that have not been studied before in order to prepare highly fluorescence hybrid systems. © 2013 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2013, 51, 1672–1679