Luteinizing hormone‐releasing hormone targeted poly(methyl vinyl ether maleic acid) nanoparticles for doxorubicin delivery to MCF‐7 breast cancer cells

The purpose of this study was to design a targeted anti‐cancer drug delivery system for breast cancer. Therefore, doxorubicin (DOX) loaded poly(methyl vinyl ether maleic acid) nanoparticles (NPs) were prepared by ionic cross‐linking method using Zn²⁺ ions. To optimise the effect of DOX/polymer ratio, Zn/polymer ratio, and stirrer rate a full factorial design was used and their effects on particle size, zeta potential, loading efficiency (LE, %), and release efficiency in 72 h (RE₇₂, %) were studied. Targeted NPs were prepared by chemical coating of tiptorelin/polyallylamin conjugate on the surface of NPs by using 1‐ethyl‐3‐(3‐dimethylaminopropyl) carboiimid HCl as cross‐linking agent. Conjugation efficiency was measured by Bradford assay. Conjugated triptorelin and targeted NPs were studied by Fourier‐transform infrared spectroscopy (FTIR). The cytotoxicity of DOX loaded in targeted NPs and non‐targeted ones were studied on MCF‐7 cells which overexpress luteinizing hormone‐releasing hormone (LHRH) receptors and SKOV3 cells as negative LHRH receptors using Thiazolyl blue tetrazolium bromide assay. The best results obtained from NPs prepared by DOX/polymer ratio of 5%, Zn/polymer ratio of 50%, and stirrer rate of 960 rpm. FTIR spectrum confirmed successful conjugation of triptorelin to NPs. The conjugation efficiency was about 70%. The targeted NPs showed significantly less IC₅₀ for MCF‐7 cells compared to free DOX and non‐targeted NPs.Inspec keywords: nanoparticles, polymer blends, cancer, cellular biophysics, drug delivery systems, drugs, biomedical materials, zinc, positive ions, Fourier transform infrared spectra, nanomedicine, proteinsOther keywords: luteinizing hormone‐releasing hormone, poly(methyl vinyl ether maleic acid), doxorubicin delivery, MCF‐7 breast cancer cell, anticancer drug delivery system, doxorubicin‐loaded PVM‐MA nanoparticle, ionic cross‐linking method, zinc ion, doxorubicin‐polymer ratio effect, zinc‐polymer ratio effect, particle size, zeta potential, loading efficiency, release efficiency, chemical coating, tiptorelin‐polyallylamin conjugation, PVM‐MA nanoparticle surface, 1‐ethyl‐3‐(3‐dimethylaminopropyl) carboiimid HCl, cross‐linking agent, Bradford assay, Fourier transform infrared spectroscopy, cytotoxicity, LHRH receptor, SKOV3 cell, Thiazolyl blue tetrazolium bromide assay, conjugation efficiency, time 72 h, Zn²⁺      

Trastuzumab‐conjugated nanoparticles composed of poly(butylene adipate‐co ‐butylene terephthalate) prepared by electrospraying technique for targeted delivery of docetaxel

Human epidermal growth factor receptor 2 (HER‐2) is overexpressed in 20–30% of human breast cancers, associated with poor prognosis and tumour aggression. The aim of this study was the production of trastuzumab‐targeted Ecoflex nanoparticles (NPs) loaded with docetaxel and in vitro evaluation of their cytotoxicity and cellular uptake. The NPs were manufactured by electrospraying and characterised regarding size, zeta potential, drug loading, and release behaviour. Then their cytotoxicity was evaluated by MTT assay against an HER‐2‐positive cell line, BT‐474, and an HER‐2‐negative cell line, MDA‐MB‐468. The cellular uptake was studied by flow cytometry and fluorescent microscope. The particle size of NPs was in an appropriate range, with relatively high drug entrapment and acceptable release efficiency. The results showed no cytotoxicity for the polymer, but the significant increment of cytotoxicity was observed by treatment with docetaxel‐loaded NPs in both HER‐2‐positive and HER‐2‐negative cell lines, in comparison with the free drug. The trastuzumab‐targeted NPs also significantly enhanced cytotoxicity against BT‐474 cells, compared with non‐targeted NPs.Inspec keywords: cancer, proteins, biomedical materials, nanofabrication, drug delivery systems, cellular biophysics, biological organs, nanomedicine, toxicology, tumours, nanoparticles, biomedical optical imaging, fluorescence, particle sizeOther keywords: human breast cancers, tumour aggression, trastuzumab‐targeted Ecoflex nanoparticles, cellular uptake, zeta potential drug loading, HER‐2‐positive cell line, HER‐2‐negative cell line, MDA‐MB‐468, particle size, trastuzumab‐conjugated nanoparticles, electrospraying technique, human epidermal growth factor receptor, cytotoxicity, nontargeted nanoparticles, butylene adipate‐co‐butylene terephthalate, trastuzumab‐targeted NP, docetaxel‐loaded NP     

Poly (vinyl alcohol)/poly (acrylamide‐ co ‐diallyldimethyl ammonium chloride) semi‐IPN hydrogels for ciprofloxacin hydrochloride drug delivery

Herein, the authors developed a new and potential semi‐interpenetrating polymer network (semi‐IPN) hydrogels of poly vinyl alcohol (PVA), acryl amide and diallyldimethyl ammonium chloride employing chemical cross‐linker N, N''‐methylene bisacrylamide (NNMBA) and ammonium persulphate as an initiator by radical polymerisation. To analyse the copolymer formation between two monomers and IPN cross‐linking reaction, the resulting hydrogel was characterised by Fourier transform infrared spectroscopy and the surface morphology was analysed using scanning electron microscopy. Differential scanning calorimetry and X‐ray diffraction studies were also carried out for investigating drug loading and distribution and swelling experiments were carried out for the uptake of water. In vitro release of ciprofloxacin hydrochloride from hydrogel was performed at intestinal conditions. The amount of PVA, NNMBA and total monomer concentration was found to strongly control the drug release behaviour from the hydrogels.Inspec keywords: hydrogels, polymer blends, biomedical materials, drug delivery systems, polymerisation, Fourier transform infrared spectra, surface morphology, scanning electron microscopy, differential scanning calorimetry, X‐ray diffraction, swelling, biological organs, ammonium compoundsOther keywords: PVA‐poly(acrylamide‐co‐diallyldimethyl ammonium chloride) semiIPN hydrogels, ciprofloxacin hydrochloride drug delivery, semiinterpenetrating polymer network hydrogels, polyvinyl alcohol, acryl amide, diallyldimethyl ammonium chloride, chemical crosslinker N,N''‐methylene bisacrylamide, ammonium persulphate, radical polymerisation initiator, NNMBA, copolymer formation, IPN crosslinking reaction, Fourier transform infrared spectroscopy, surface morphology, scanning electron microscopy, differential scanning calorimetry, X‐ray diffraction, drug loading, drug distribution, swelling, water uptake, in vitro ciprofloxacin hydrochloride release, intestinal conditions, total monomer concentration, drug release behaviour     

Development of transferrin functionalized poly(ethylene glycol)/poly(lactic acid) amphiphilic block copolymeric micelles as a potential delivery system targeting brain glioma

The aim of present study is to conceive a biodegradable poly(ethylene glycol)–polylactide (PEG–PLA) copolymer nanoparticle which can be surface biofunctionalized with ligands via biotin–avidin interactions and used as a potential drug delivery carrier targeting to brain glioma in vivo. For this aim, a new method was employed to synthesize biotinylated PEG–PLA copolymers, i.e., esterification of PEG with biotinyl chloride followed by copolymerization of hetero-biotinylated PEG with lactide. PEG–PLA nanoparticles bearing biotin groups on surface were prepared by nanoprecipitation technique and the functional protein transferrin (Tf) were coupled to the nanoparticles by taking advantage of the strong biotin–avidin complex formation. The flow cytometer measurement demonstrated the targeting ability of the nanoparticles to tumor cells in vitro, and the fluorescence microscopy observation of brain sections from C6 glioma tumor-bearing rat model gave the intuitive proof that Tf functionalized PEG–PLA nanoparticles could penetrate into tumor in vivo.     

Nanoparticles of deoxycholic acid,polyethylene glycol and folic acid-modified chitosan for targeted delivery of doxorubicin

Chitosan (CS) was first modified hydrophobically with deoxycholic acid (DCA) and then with polyethylene glycol (PEG) to obtain a novel amphiphilic polymer (CS–DCA–PEG). This was covalently bound to folic acid (FA) to develop nanoparticles (CS–DCA–PEG–FA) with tumor cell targeting property. The structure of the conjugates was characterised using Fourier transform infrared and ¹H nuclear magnetic resonance spectroscopy and X-ray diffraction. Based on self-aggregation, the conjugates formed nanoparticles with a low critical aggregation concentration of 0.035 mg/ml. The anti-cancer drug doxorubicin (DOX) was encapsulated into the nanoparticles with a drug-loading capacity of 30.2 wt%. The mean diameter of the DOX-loaded nanoparticles was about 200 nm, with a narrow size distribution. Transmission electron microscopy images showed that the DOX-loaded nanoparticles were spherical. The drug release was studied under different conditions. Furthermore, the cytotoxic activities of DOX in CS–DCA–PEG–FA nanoparticles against folate receptor (FR)-positive HeLa cells and FR-negative fibroblast 3T3 cells were evaluated. These results suggested that the CS–DCA–PEG–FA nanoparticles may be a promising vehicle for the targeting anticancer drug to tumor cells.     

Enhanced stability of L‐asparaginase by its bioconjugation to poly(styrene‐co‐maleic acid) and Ecoflex nanoparticles

Acute lymphoblastic leukemia (ALL) is the white blood cell cancer in children. L‐asparaginase (L‐ASNase) is one of the first drugs used in ALL treatment. Anti‐tumor activity of L‐ASNase is not specific and indicates limited stability in different biological environments, in addition to its quick clearance from blood. The purpose of the present study was to achieve a new L‐ASNase polymer bioconjugate to improve pharmacokinetic, increase half‐life and stability of the enzyme. The conjugations were achieved by the cross‐linking agent of 1‐ethyl‐3‐(3‐ dimethylaminopropyl) carbodiimide (EDC) which activates the carboxylic acid groups of polymeric nanoparticles to create amide bond. EDC conjugated the L‐ASNase to two biodegradable polymers including; Ecoflex^® and poly (styrene‐co‐maleic acid) (PSMA) nanoparticles. To achieve optimal L‐ASNase nanoparticles the amounts of each polymer and the crosslinker were optimized and the nanoparticles were characterized according to their particle size, zeta potential and percent of conjugation of the enzyme. The results showed that conjugated enzyme had more stability against pH changes and proteolysis. It had lower Km value (indicating more affinity to the substrate) and greater half‐life in plasma and phosphate buffered saline, in comparison to native enzyme. Generally, the conjugated enzyme to PSMA nanoparticles showed greater results than Ecoflex^® nanoparticles.Inspec keywords: enzymes, polymer blends, nanomedicine, biomedical materials, blood, nanoparticles, cancer, molecular biophysics, molecular configurations, biochemistry, conducting polymers, electrokinetic effects, particle size, bonds (chemical), biodegradable materials, pHOther keywords: enhanced stability, L‐asparaginase, bioconjugation, poly(styrene‐co‐maleic acid), Ecoflex nanoparticles, acute lymphoblastic leukaemia, white blood cell cancer, children, drugs, ALL treatment, antitumour activity, biological environments, L‐ASNase polymer bioconjugate, pharmacokinetic, enzyme, crosslinking agent, amide bond, 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide, carboxylic acid groups, polymeric nanoparticles, EDC conjugation, biodegradable polymers, PSMA nanoparticles, optimal L‐ASNase nanoparticles, particle size, zeta potential, pH changes, proteolysis, native enzyme, conjugated enzyme     

Preparation and characterization of chitosan/poly(vinyl alcohol)/poly(vinyl pyrrolidone) electrospun fibers

Ultrafine fibers of chitosan/poly(vinyl alcohol)/poly(vinyl pyrrolidone) (CS/PVA/PVP) were prepared via electrospinning. The structure and morphology of CS/PVA/PVP ultrafine fibers was characterized by the Fourier transform infrared (FT-IR) spectroscope and scanning electron microscope (SEM). Furthermore, the effects of the concentration of PVA, PVP and the electrospinning voltage on the morphology of ultrafine fibers were investigated the the SEM. When the concentration of PVA was at the range of 30wt%–40wt%, ultrafine fibers could be obtained. The diameter distributions of ultrafine fibers decreased when the electrospinning voltage increased from 20 to 30 kV. The rough surface fibers could be obtained after etching with CHCl₃.     

Fabrication of poly(D,L‐lactic acid) nanoparticles as delivery system for sustained release of L‐theanine

L‐theanine is present in tea as a unique, free, non‐protein amino acid. Due to various beneficial effects on brain activity, it is widely used as a nutraceutical. After consumption, it is rapidly absorbed and metabolised followed by excretion through urine. Therefore, the authors developed an L‐theanine delivery system by encapsulating into polymeric nanoparticles to release it slowly and make it available for a longer period of time. Poly(D, L‐lactic acid) nanoparticle (PLANP) was fabricated by the double emulsion method and L‐theanine was encapsulated into it (PLANP‐T). Spherical nanoparticles with a hydrodynamic diameter of 247 and 278 nm and surface charge of −14.5 and −25.7 mV for PLANP and PLANP‐T, respectively, were fabricated. The Fourier transform infrared spectroscopic data indicated encapsulation of L‐theanine into PLANP. The PLANP showed high L‐theanine encapsulation capacity (71.65%) with a sustained release character. The maximum release (66.3%) of L‐theanine was recorded in pH 7.3 at 48 h. The release kinetics followed the Higuchi model and the release mechanism was determined as super case‐II transport (erosion). This slow release will make it available to the target tissue for a longer period of time (sustain release effect) and will also avoid immediate metabolism and clearance from the circulation.Inspec keywords: nanomedicine, pH, polymers, nanofabrication, emulsions, biomedical materials, drug delivery systems, nanoparticles, Fourier transform infrared spectraOther keywords: brain activity, L‐theanine delivery system, polymeric nanoparticles, double emulsion method, spherical nanoparticles, surface charge, L‐theanine encapsulation capacity, poly(D, L‐lactic acid) nanoparticles, nonprotein amino acid, urine, hydrodynamic diameter, Fourier transform infrared spectroscopy, time 48.0 hour, voltage ‐25.7 mV, voltage ‐14.5 mV, size 278.0 nm, size 247.0 nm, target tissue, Higuchi model, pH     

马来酰己二胺酸改性聚乳酸的合成与表征

以马来酸酐和己二胺为原料制备出了一种新型的马来酰己二胺酸单体（HOOC-MAH-HDA-NH2）,然后采用自由基熔融接枝技术将HOOC-MAH-HDA-NH2引入到PDLLA骨架中,形成了结构与己二胺改性聚乳酸（HMPDLLA）相似的MHP-DLLA材料。采用红外光谱（FT-IR）、核磁共振氢谱（1 H NMR）、核磁共振碳谱（13 C NMR）和DEPT 135对HOOC-MAH-HDA-NH2和MHPDLLA的化学结构进行了定性和定量表征。以PDLLA为空白,HMP-DLLA为对照,对MHPDLLA的分子量进行了测定。结果表明采用新的合成工艺使聚合物的分子量从原有的66%～68%降低到了33%～34%,且合成路线更简单。在合成路线和合成工艺上的创新为MHPDLLA用作生物活性材料或仿生材料的基质材料开辟了更广阔的空间。     

Biodegradable poly(amine-co-ester) terpolymers for targeted gene delivery

Many synthetic polycationic vectors for non-viral gene delivery show high efficiency in vitro, but their usually excessive charge density makes them toxic for in vivo applications. Here we describe the synthesis of a series of high molecular weight terpolymers with low charge density, and show that they exhibit efficient gene delivery, some surpassing the efficiency of the commercial transfection reagents Polyethylenimine and Lipofectamine 2000. The terpolymers were synthesized via enzyme-catalyzed copolymerization of lactone with dialkyl diester and amino diol, and their hydrophobicity adjusted by varying the lactone content and by selecting a lactone comonomer of specific ring size. Targeted delivery of the pro-apoptotic TRAIL gene to tumour xenografts by one of the terpolymers results in significant inhibition of tumour growth, with minimal toxicity both in vitro and in vivo. Our findings suggest that the gene delivery ability of the terpolymers stems from their high molecular weight and increased hydrophobicity, which compensates for their low charge density.     

Nano-sized micelles of block copolymers of methoxy poly(ethylene glycol)-poly(epsilon-caprolactone)-graft-2-hydroxyethyl cellulose for doxorubicin delivery

The amphiphilic block copolymers methoxy poly(ethylene glycol)-poly(epsilon-caprolactone) was grafted to 2-hydroxyethyl cellulose to produce the water-soluble copolymers. Doxorubicin loaded nanoparticles were prepared by dialysis method and the sizes of nanoparticles were determined by dynamic light scattering in solution and atomic force microscopes. As results the sizes were detected in a range of 197.4 to 340.7 nm. The in-vitro release of Dox was studied in phosphate and acetate buffered solution at 37 degrees C. The results showed that 43 and 53% of Dox remained after an incubation period of 7 days. The cytotoxicity of Dox loaded micelles was investigated in two different human MCF-7/wild type and MCF-7/Adriamycin drug resistant cells lines. The Dox-loaded micelles showed reduced cytotoxicity compared to free Dox in MCF-7/wild type and MCF-7/Adriamycin drug resistant cells.     

Biodegradable and redox-responsive chitosan/poly(l-aspartic acid) submicron capsules for transmucosal delivery of proteins and peptides

The development of peptides and proteins is hampered by their rapid clearance in liver and other body tissues by proteolytic enzymes, so these drugs are difficult to administer except for the injection. Here, we designed and fabricated a novel biodegradable and redox-responsive submicron capsules through the layer-by-layer technique with poly(l-aspartic acid) and chitosan for transmucosal delivery of proteins and peptides. TEM graphs reveal that the intact submicron capsules were obtained and the shell of submicron capsules was about 40 nm. The mucoadhesion test indicates that the adsorption amount of the mucin could achieve up to 96.2 μg per 2 mg. The cell viability test shows that all types of submicron capsules had good cytocompatibility and the cell viability was above 90 %. As a drug model, the insulin could be loaded in the submicron capsules, and the loading efficiency was about 5 %. The release amount of insulin could be regulated by the levels of GSH. Therefore, the mucoadhesive submicron capsules as vehicles have a potential for the mucosal delivery (e.g. nasal and buccal) of therapeutic peptide and protein drugs.     

Thermosensitive Y-shaped micelles of poly(oleic acid-Y-N-isopropylacrylamide) for drug delivery

A novel thermosensitive amphiphilic copolymer comprised of two hydrophobic poly(oleic acid) (POA) segments and one hydrophilic poly(N-isopropylacrylamide) (PNIPAAm) segment was designed and synthesized. The structure of the copolymer was confirmed as Y-shaped by FTIR, 1H NMR, and SEC-MALLS analysis. A cytotoxicity study shows that the P(OA-Y-NIPAAm) copolymer exhibits good biocompatibility. The copolymer may self-assemble into micelles in water, with the hydrophobic POA segments at the cores of micelles and the hydrophilic PNIPAAm segments as the outer shells. The resulting micelles demonstrate temperature sensitivity with a lower critical solution temperature (LCST) of 31.5 degrees C and a critical micelle concentration (CMC) of 12.6 mg L(-1). Transmission electron microscopy (TEM) shows that the micelles exhibit a nanospheric morphology within a narrow size range of approximately 10-30 nm. A study of controlled release reveals that the self-assembled micelles have great potential as drug carriers.     

Characterizing poly(epsilon-caprolactone)-b-chitooligosaccharide-b-poly(ethylene glycol) (PCP) copolymer micelles for doxorubicin (DOX) delivery: effects of crosslinked of amine groups

New amine-groups containing tri-block copolymers and micelles that consisting of poly(epsilon-caprolactone)-b-chitooligosaccharide-b-poly(ethylene glycol) (PCL-b-COS-b-PEG, PCP), were synthesized, characterized, and evaluated for delivering doxorubicin (DOX) with or without crosslinked amine groups by genipin. The characteristics of the PCP copolymers of Fourier-transform infrared spectrometry (FT-IR) verify the amine and ester groups of the COS and the PCL of the copolymers, respectively. 1H nuclear magnetic resonance (1H NMR) spectra verify the structures of the PCP copolymers consisting two PCL and PEG polymers reacted onto the COS block. In addition, gel permeation chromatography (GPC) determines the number average molecular weight of the tri-block copolymers (Mn) of approximately 11340 Da/mole. The PCP copolymers can self-assemble to form polymeric micelles at the critical micelle concentration (CMC) of 1.0 microM as determined by the UV-VIS absorption spectra. The mean diameter of the PCP micelles is 90 nm, as determined using a dynamic light-scattering (DLS) analyzer. Moreover, the zeta potentials of PCP micelles change from neutral to cationic state when pH of suspension mediums varied from 7.4 to 3.0. For evaluating delivery characteristics of hydrophobic DOX, it was loaded into PCP micelles with or without crosslinked by genipin. The burst release and release period of DOX for the crosslinked micelles are significantly reduced (P < 0.003, n = 3, for pH = 7.4) and sustained (e.g., 8 days), respectively, than those non-crosslinked ones (e.g., 4 days). In conclusion, new tri-block amine groups containing PCP copolymers are synthesized that can self-assemble as PCP micelles. After post-crosslinked amine groups of DOX loaded the micelles, they can effectively reduce the burst release and sustain the release of DOX at different pH dissolution mediums. Further applications of PCP copolymers and micelles for drug delivery can be explored in future.     

Synthesis and characterization of nanofiber webs of chitosan/poly(vinyl alcohol) blends incorporated with silver nanoparticles

Nanofiber webs of chitosan (CS)/poly(vinyl alcohol) (PVA) blends incorporated with silver nanoparticles (AgNs) were fabricated by two different methods: a refluxing method and an annealing method. We found that the characterization and antibacterial activity of AgNs depended on not only the fabrication methods but also the weight ratio of CS and PVA in the CS/PVA blend. The change in the size and number of AgNs due to the interaction between AgNs and CS, in turn, affected the antibacterial property of the non-woven webs. Non-woven webs of CS/PVA nanofibers containing AgNs that were fabricated by the refluxing method showed higher antibacterial ability against Escherichia coli than did the other types of non-woven webs. The morphology of the electrospun non-woven webs was observed by field emission scanning electron microscopy. The characterization of AgN formation on the surface of electrospun fibers was examined by transmission electron microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy.     

Preparation and characterization of galactosylated glycol chitosan micelles and its potential use for hepatoma-targeting delivery of doxorubicin

This study aimed to develop novel galactosylated cholesterol modified-glycol chitosan (Gal-CHGC) micelles for targeting delivery of doxorubicin (DOX) in live cancer cells. Three kinds of Gal-CHGC conjugates were synthesized and characterized. The mean particle size and critical aggregation concentration of these polymeric micelles increased with the increase of galactose substitution degree. The DOX-loaded micelles were prepared by an o/w method. The mean diameters of DOX-loaded galactosylated micelles were in the range of 387–497 nm. DOX released from drug-loaded micelles displayed a biphasic way. Cellular uptake studies demonstrated that DOX-loaded galactosylated micelles could enhance the uptake of DOX into HepG2 cells. Moreover, the cytotoxicity of DOX-loaded galactosylated micelles against HepG2 cells significantly improved in contrast with free DOX and DOX-loaded micelles without galactosylation. These results suggested that Gal-CHGC micelles could be a potential carrier for hepatoma-targeting drug delivery.     

Facile nano‐free electrochemiluminescence biosensor for detection of sulphamethoxazole via tris(2,2′‐bipyridyl)ruthenium(II) and N ‐methyl pyrrolidone recognition

The electrochemiluminescence (ECL) system based on the ruthenium complex has become a powerful tool in the field of analytical chemistry. However, the non‐aqueous ECL luminescence system, which does not involve complex nano‐modification, has not been widely used for the determination of analytes. In this study, N ‐methyl pyrrolidone was selected as the solvent, and it could also act as a co‐reactant of Rubpy32+. Based on this, a simple ECL system without nanomaterials was established. Strong ECL was generated. Furthermore, a quenching effect between the excited state of Rubpy32+ and sulphamethoxazole (SMZ) was observed. Based on this, a sensitive ECL sensor for detecting SMZ is constructed. A linear relationship between ECL signal quenching intensity (ΔI) and the logarithm of SMZ concentration (log C) in the concentration range of 1 × 10⁻⁷ –1 × 10⁻⁵ mol/l is obtained. The limit of detection is as low as 3.33 × 10⁻⁹ mol/l. The method has been applied to the detection of SMZ in tap water samples with different concentration levels with satisfactory results, and the recovery was 95.3–102.6%.Inspec keywords: biosensors, electrochemical sensors, electroluminescence, chemiluminescence, organic compounds, electrochemistryOther keywords: ruthenium complex, analytical chemistry, nonaqueous ECL luminescence system, complex nanomodification, quenching effect, ECL signal quenching intensity, ECL sensor system, nanofree electrochemiluminescence biosensor system, sulphamethoxazole detection, tris(2,2′‐bipyridyl)ruthenium(II), N‐methyl pyrrolidone recognition, analyte determination, nanomaterials, SMZ concentration detection     

Poly (ɛ‐caprolactone)–chitosan–poly (vinyl alcohol) nanofibrous scaffolds for skin excisional and burn wounds in a canine model

Poly (ɛ‐caprolactone)–chitosan–poly (vinyl alcohol) (PCL: Cs: PVA) nanofibrous blend scaffolds were known as useful materials for skin wound healing and would help the healing process about 50% faster at the final time point. From the previous studies by the authors, PCL: Cs: PVA (in 2: 1: 1.5 mass ratio) nanofibres showed high efficacy in healing on rat models. In this study, the scaffolds were examined in burn and excision wounds healing on dogs as bigger models. The scaffolds were applied on dorsum skin wounds (n  = 5) then macroscopic and microscopic investigations were carried out to measure the wounds areas and to track healing rate, respectively. Macroscopic results showed good aspect healing effect of scaffolds compared with control wounds especially after 21 days post‐operating for both cutting and burn wounds. Pathological studies showed that the healing rates of the wounds covered with PCL: Cs: PVA nanofibrous scaffolds were much rapid compared to untreated wounds in control group. The immunogenicity of the scaffolds in canine model was also investigated. The findings showed that nanofibrous blend scaffolds was not immunogenic in humoural immune responses. All these results indicated that PCL: Cs: PVA nanofibrous web could be considered as promising materials for wounds healings.Inspec keywords: nanofibres, nanomedicine, biomedical materials, polymer fibres, polymer blends, skin, woundsOther keywords: poly(ε‐caprolactone)‐chitosan‐poly (vinyl alcohol) nanofibrous blend scaffolds, skin excisional wounds, burn wounds, canine model, skin wound healing, dorsum skin wounds, macroscopic investigations, microscopic investigations, healing rate, cutting wounds, pathological study, humoural immune responses, nanofibrous web, immunogenicity, time 21 day     

Poly (vinyl alcohol) hydrogels for pH dependent colon targeted drug delivery

Oral drug administration is convenient with pH dependent drug delivery system since the drug has to pass through different pH environments in gastro intestinal (GI) tract. The pH dependent swelling/shrinking behavior of hydrogel drug carrier controls the drug release without affecting the function of drug. pH dependent hydrogels of poly (vinyl alcohol) (PVA) were prepared by cross linking with maleic acid (MA). The hydrogels were characterized by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, DSC, porosimetry, SEM, TEM, biocompatibility study and by measuring their swelling behavior in water, simulated gastric fluid (SGF) and intestinal fluid (SIF). Swelling of the hydrogels was found to be highest in SIF (pH: 7.5) and lowest in SGF (pH: 1.2) resembling that required in colon targeted drug delivery systems. Since the swelling behavior of the gel is pH dependent, these hydrogels were studied for colon targeted drug delivery in an in-vitro set-up resembling the condition of GI tract. The ratio of PVA and MA in the hydrogel was varied to study the effect on the drug diffusion rate. For drug delivery study, vitamin B₁₂ and salicylic acid were used as model drugs. The hydrogel, loaded with model drugs vitamin B₁₂ and salicylic acid also demonstrated colon specific drug release with a relatively higher drug release in SIF (pH: 7.5) than that in SGF (pH: 1.2).     

Poly (vinyl alcohol) hydrogels for pH dependent colon targeted drug delivery

Oral drug administration is convenient with pH dependent drug delivery system since the drug has to pass through different pH environments in gastro intestinal (GI) tract. The pH dependent swelling/shrinking behavior of hydrogel drug carrier controls the drug release without affecting the function of drug. pH dependent hydrogels of poly (vinyl alcohol) (PVA) were prepared by cross linking with maleic acid (MA). The hydrogels were characterized by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, DSC, porosimetry, SEM, TEM, biocompatibility study and by measuring their swelling behavior in water, simulated gastric fluid (SGF) and intestinal fluid (SIF). Swelling of the hydrogels was found to be highest in SIF (pH: 7.5) and lowest in SGF (pH: 1.2) resembling that required in colon targeted drug delivery systems. Since the swelling behavior of the gel is pH dependent, these hydrogels were studied for colon targeted drug delivery in an in-vitro set-up resembling the condition of GI tract. The ratio of PVA and MA in the hydrogel was varied to study the effect on the drug diffusion rate. For drug delivery study, vitamin B12 and salicylic acid were used as model drugs. The hydrogel, loaded with model drugs vitamin B12 and salicylic acid also demonstrated colon specific drug release with a relatively higher drug release in SIF (pH: 7.5) than that in SGF (pH: 1.2).