Displaying publications 201 - 220 of 255 in total

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  1. Development of an implantable D-serine biosensor for in vivo monitoring using mammalian D-amino acid oxidase on a poly (o-phenylenediamine) and Nafion-modified platinum-iridium disk electrode
    Zain ZM, O'Neill RD, Lowry JP, Pierce KW, Tricklebank M, Dewa A, et al.
    Biosens Bioelectron, 2010 Feb 15;25(6):1454-9.
    PMID: 19945264 DOI: 10.1016/j.bios.2009.10.049
    D-serine has been implicated as a brain messenger, promoting not only neuronal signalling but also synaptic plasticity. Thus, a sensitive tool for D-serine monitoring in brain is required to understand the mechanisms of D-serine release from glia cells. A biosensor for direct fixed potential amperometric monitoring of D-serine incorporating mammalian D-amino acid oxidase (DAAO) immobilized on a Nafion coated poly-ortho-phenylenediamine (PPD) modified Pt-Ir disk electrode was therefore developed. The combined layers of PPD and Nafion enhanced the enzyme activity and biosensor efficiency by approximately 2-fold compared with each individual layer. A steady state response time (t(90%)) of 0.7+/-0.1s (n=8) and limit of detection 20+/-1 nM (n=8) were obtained. Cylindrical geometry showed lower sensitivity compared to disk geometry (61+/-7 microA cm(-2) mM(-1), (n=4), R(2)=0.999). Interference by ascorbic acid (AA), the main interference species in the central nervous system and other neurochemical electroactive molecules was negligible. Implantation of the electrode and microinjection of D-serine into rat brain striatal extracellular fluid demonstrated that the electrode was capable of detecting D-serine in brain tissue in vivo.
    Matched MeSH terms: Fluorocarbon Polymers/chemistry
  2. Microbial colonization of medical devices and novel preventive strategies
    Shunmugaperumal T
    Recent Pat Drug Deliv Formul, 2010 Jun;4(2):153-73.
    PMID: 20236065
    Upon implantation or insertion into patient's body for exerting the intended purpose like salvage of normal functions of vital organs, the medical devices are unfortunately becoming the sites of competition between host cell integration and microbial adhesion. Moreover, since there is an increased use of implanted medical devices, the incidence of biofilm-and medical devices-related nosocomial infections is also increasing progressively. To control microbial colonization and subsequent biofilm formation of the medical devices, different approaches either to enhance the efficiency of certain antimicrobial agents or to disrupt the basic physiology of the pathogenic microorganisms including novel small molecules and antipathogenic drugs are being explored. In addition, the various lipid-and polymer-based drug delivery carriers are also investigated for applying antibiofilm coating of the medical devices especially over catheters. The main intention of this review is therefore to summarize the major and/breakthrough inventions disclosed in patent literature as well as in research papers related to microbial colonization of medical devices and novel preventive strategies. This review starts with an overview of the preventive strategies followed by a short description about the potential of different lipidic-and polymeric-drug delivery carriers in eradicating the biofilm-associated infections from the medical devices.
    Matched MeSH terms: Polymers/chemistry
  3. FT-IR studies on interactions among components in hexanoyl chitosan-based polymer electrolytes
    Winie T, Arof AK
    Spectrochim Acta A Mol Biomol Spectrosc, 2006 Mar 1;63(3):677-84.
    PMID: 16157506
    Fourier transform infrared (FT-IR) spectroscopic studies have been undertaken to investigate the interactions among components in a system of hexanoyl chitosan-lithium trifluoromethanesulfonate (LiCF(3)SO(3))-diethyl carbonate (DEC)/ethylene carbonate (EC). LiCF(3)SO(3) interacts with the hexanoyl chitosan to form a hexanoyl chitosan-salt complex that results in the shifting of the N(COR)(2), CONHR and OCOR bands to lower wavenumbers. Interactions between EC and DEC with LiCF(3)SO(3) has been noted and discussed. Evidence of interaction between EC and DEC has been obtained experimentally. Studies on polymer-plasticizer spectra suggested that there is no interaction between the polymer host and plasticizers. Competition between plasticizer and polymer on associating with Li(+) ions was observed from the spectral data for gel polymer electrolytes. The obtained spectroscopic data has been correlated with the conductivity performance of hexanoyl chitosan-based polymer electrolytes.
    Matched MeSH terms: Polymers/chemistry*
  4. Drug release property of chitosan-pectinate beads and its changes under the influence of microwave
    Wong TW, Nurjaya S
    Eur J Pharm Biopharm, 2008 May;69(1):176-88.
    PMID: 17980563
    The effects of microwave irradiation on the drug release property of pectinate beads loaded internally with chitosan (chitosan-pectinate beads) were investigated against the pectinate beads and beads coacervated with chitosan externally (pectinate-chitosonium beads). These beads were prepared by an extrusion method using sodium diclofenac as the model water-soluble drug. The beads were subjected to microwave irradiation at 80 W for 5, 10, 21 and 40 min. The profiles of drug dissolution, drug content, drug-polymer interaction and polymer-polymer interaction were determined by drug dissolution testing, drug content assay, drug adsorption study, differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR) techniques. Treatment of pectinate beads by microwave did not lead to a decrease, but an increase in the extent of drug released at 4h of dissolution owing to reduced pectin-pectin interaction via the CO moiety of polymer. In addition, the extent of drug released from the pectinate beads could not be reduced merely through the coacervation of pectinate matrix with chitosan. The reduction in the extent of drug released from the pectinate-chitosonium beads required the treatment of these beads by microwave, following an increase in drug-polymer and polymer-polymer interaction in the matrix. The extent of drug released from the pectinate beads was reduced through incorporating chitosan directly into the interior of pectinate matrix, owing to drug-chitosan adsorption. Nonetheless, the treatment of chitosan-pectinate matrix by microwave brought about an increase in the extent of drug released unlike those of pectinate-chitosonium beads. Apparently, the loading of chitosan into the interior of pectinate matrix could effectively retard the drug release without subjecting the beads to the treatment of microwave. The microwave was merely essential to reduce the release of drug from pectinate beads when the chitosan was introduced to the pectinate matrix by means of coacervation. Under the influences of microwave, the drug release property of beads made of pectin and chitosan was mainly modulated via the CH, OH and NH moieties of polymers and drug, with CH functional group purported to retard while OH and NH moieties purported to enhance the drug released from the matrix.
    Matched MeSH terms: Polymers/chemistry
  5. Development and In Vitro Evaluation of Aceclofenac Buccal Film
    Almurisi SH, Mohammed A, Qassem F, Jehad H, Jassim A, Al-Japairai K, et al.
    Curr Drug Discov Technol, 2024;21(3):46-55.
    PMID: 37807409 DOI: 10.2174/0115701638262447230920061222
    AIM: This study aimed to formulate and characterize aceclofenac buccal film formulations made of different polymers and evaluate the effects of polymer type on buccal film properties.

    MATERIALS AND METHODS: Five polymer types, namely hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose (SCMC), polyvinyl alcohol (PVA), Eudragit S100, and Eudragit SR100, were used to prepare aceclofenac buccal film formulation either separately or combined by solvent-casting method. These formulations were evaluated in terms of physical appearance, folding test, film weight and thickness, drug content, percentage of elongation, moisture uptake, water vapor permeability, and in vitro drug release.

    RESULTS: The addition of Eudragit polymer in most of the produced buccal films was unacceptable with low folding endurance. However, the dissolution profile of buccal films made from PVA and Eudragit SR100 provided a controlled drug release profile.

    CONCLUSION: Buccal films can be formulated using different polymers either individually or in combination to obtain the drug release profile required to achieve a desired treatment goal. Furthermore, the property of the buccal films depends on the type and concentration of the polymer used.

    Matched MeSH terms: Polymers/chemistry
  6. Fulltext Nanobiocatalyst advancements and bioprocessing applications
    Misson M, Zhang H, Jin B
    J R Soc Interface, 2015 Jan 06;12(102):20140891.
    PMID: 25392397 DOI: 10.1098/rsif.2014.0891
    The nanobiocatalyst (NBC) is an emerging innovation that synergistically integrates advanced nanotechnology with biotechnology and promises exciting advantages for improving enzyme activity, stability, capability and engineering performances in bioprocessing applications. NBCs are fabricated by immobilizing enzymes with functional nanomaterials as enzyme carriers or containers. In this paper, we review the recent developments of novel nanocarriers/nanocontainers with advanced hierarchical porous structures for retaining enzymes, such as nanofibres (NFs), mesoporous nanocarriers and nanocages. Strategies for immobilizing enzymes onto nanocarriers made from polymers, silicas, carbons and metals by physical adsorption, covalent binding, cross-linking or specific ligand spacers are discussed. The resulting NBCs are critically evaluated in terms of their bioprocessing performances. Excellent performances are demonstrated through enhanced NBC catalytic activity and stability due to conformational changes upon immobilization and localized nanoenvironments, and NBC reutilization by assembling magnetic nanoparticles into NBCs to defray the high operational costs associated with enzyme production and nanocarrier synthesis. We also highlight several challenges associated with the NBC-driven bioprocess applications, including the maturation of large-scale nanocarrier synthesis, design and development of bioreactors to accommodate NBCs, and long-term operations of NBCs. We suggest these challenges are to be addressed through joint collaboration of chemists, engineers and material scientists. Finally, we have demonstrated the great potential of NBCs in manufacturing bioprocesses in the near future through successful laboratory trials of NBCs in carbohydrate hydrolysis, biofuel production and biotransformation.
    Matched MeSH terms: Polymers/chemistry*
  7. Application of solid-phase extraction for trace elements in environmental and biological samples: a review
    Wan Ibrahim WA, Abd Ali LI, Sulaiman A, Sanagi MM, Aboul-Enein HY
    Crit Rev Anal Chem, 2014;44(3):233-54.
    PMID: 25391563 DOI: 10.1080/10408347.2013.855607
    The progress of novel sorbents and their function in preconcentration techniques for determination of trace elements is a topic of great importance. This review discusses numerous analytical approaches including the preparation and practice of unique modification of solid-phase materials. The performance and main features of ion-imprinting polymers, carbon nanotubes, biosorbents, and nanoparticles are described, covering the period 2007-2012. The perspective and future developments in the use of these materials are illustrated.
    Matched MeSH terms: Polymers/chemistry
  8. Fulltext The effect of different parameters on the development of compressive strength of oil palm shell geopolymer concrete
    Kupaei RH, Alengaram UJ, Jumaat MZ
    ScientificWorldJournal, 2014;2014:898536.
    PMID: 25531006 DOI: 10.1155/2014/898536
    This paper presents the experimental results of an on-going research project on geopolymer lightweight concrete using two locally available waste materials--low calcium fly ash (FA) and oil palm shell (OPS)--as the binder and lightweight coarse aggregate, respectively. OPS was pretreated with three different alkaline solutions of sodium hydroxide (NaOH), potassium hydroxide, and sodium silicate as well as polyvinyl alcohol (PVA) for 30 days; afterwards, oil palm shell geopolymer lightweight concrete (OPSGPC) was cast by using both pretreated and untreated OPSs. The effect of these solutions on the water absorption of OPS, and the development of compressive strength in different curing conditions of OPSGPC produced by pretreated OPS were investigated; subsequently the influence of NaOH concentration, alkaline solution to FA ratio (A/FA), and different curing regimes on the compressive strength and density of OPSGPC produced by untreated OPS was inspected. The 24-hour water absorption value for OPS pretreated with 20% and 50% PVA solution was about 4% compared to 23% for untreated OPS. OPSGPC produced from OPS treated with 50% PVA solution produced the highest compressive strength of about 30 MPa in ambient cured condition. The pretreatment with alkaline solution did not have a significant positive effect on the water absorption of OPS aggregate and the compressive strength of OPSGPC. The result revealed that a maximum compressive strength of 32 MPa could be obtained at a temperature of 65°C and curing period of 4 days. This investigation also found that an A/FA ratio of 0.45 has the optimum amount of alkaline liquid and it resulted in the highest level of compressive strength.
    Matched MeSH terms: Polymers/chemistry*
  9. Influence of bentonite in polymer membranes for effective treatment of car wash effluent to protect the ecosystem
    Kiran SA, Arthanareeswaran G, Thuyavan YL, Ismail AF
    Ecotoxicol Environ Saf, 2015 Nov;121:186-92.
    PMID: 25869419 DOI: 10.1016/j.ecoenv.2015.04.001
    In this study, modified polyethersulfone (PES) and cellulose acetate (CA) membranes were used in the treatment of car wash effluent using ultrafiltration. Hydrophilic sulfonated poly ether ether ketone (SPEEK) and bentonite as nanoclay were used as additives for the PES and CA membrane modification. Performances of modified membranes were compared with commercial PES membrane with 10kDa molecular weight cut off (MWCO). The influencing parameters like stirrer speed (250-750rpm) and transmembrane pressure (100-600kPa) (TMP) were varied and their effects were studied as a function of flux. In the treatment of car wash effluent, a higher permeate flux of 52.3L/m(2)h was obtained for modified CA membrane at TMP of 400kPa and stirrer speed of 750rpm. In comparison with modified PES membrane and commercial PES membrane, modified CA membranes showed better performance in terms of flux and flux recovery ratio. The highest COD removal (60%) was obtained for modified CA membrane and a lowest COD removal (47%) was observed for commercial PES membrane. The modified membranes were better at removing COD, turbidity and maintained more stable flux than commercial PES membrane, suggesting they will provide better economic performance in car wash effluent reclamation.
    Matched MeSH terms: Polymers/chemistry*
  10. Punctal plug: a medical device to treat dry eye syndrome and for sustained drug delivery to the eye
    Yellepeddi VK, Sheshala R, McMillan H, Gujral C, Jones D, Raghu Raj Singh T
    Drug Discov Today, 2015 Jul;20(7):884-9.
    PMID: 25668579 DOI: 10.1016/j.drudis.2015.01.013
    Punctal plugs (PPs) are miniature medical implants that were initially developed for the treatment of dry eyes. Since their introduction in 1975, many PPs made from different materials and designs have been developed. PPs, albeit generally successful, suffer from drawbacks such as epiphora and suppurative canaliculitis. To overcome these issues intelligent designs of PPs were proposed (e.g. SmartPLUG™ and Form Fit™). PPs are also gaining interest among pharmaceutical scientists for sustaining drug delivery to the eye. This review aims to provide an overview of PPs for dry eye treatment and drug delivery to treat a range of ocular diseases. It also discusses current challenges in using PPs for ocular diseases.
    Matched MeSH terms: Polymers/chemistry*
  11. Synthesis, mechanical properties, and in vitro biocompatibility with osteoblasts of calcium silicate-reduced graphene oxide composites
    Mehrali M, Moghaddam E, Shirazi SF, Baradaran S, Mehrali M, Latibari ST, et al.
    ACS Appl Mater Interfaces, 2014 Mar 26;6(6):3947-62.
    PMID: 24588873 DOI: 10.1021/am500845x
    Calcium silicate (CaSiO3, CS) ceramics are promising bioactive materials for bone tissue engineering, particularly for bone repair. However, the low toughness of CS limits its application in load-bearing conditions. Recent findings indicating the promising biocompatibility of graphene imply that graphene can be used as an additive to improve the mechanical properties of composites. Here, we report a simple method for the synthesis of calcium silicate/reduced graphene oxide (CS/rGO) composites using a hydrothermal approach followed by hot isostatic pressing (HIP). Adding rGO to pure CS increased the hardness of the material by ∼40%, the elastic modulus by ∼52%, and the fracture toughness by ∼123%. Different toughening mechanisms were observed including crack bridging, crack branching, crack deflection, and rGO pull-out, thus increasing the resistance to crack propagation and leading to a considerable improvement in the fracture toughness of the composites. The formation of bone-like apatite on a range of CS/rGO composites with rGO weight percentages ranging from 0 to 1.5 has been investigated in simulated body fluid (SBF). The presence of a bone-like apatite layer on the composite surface after soaking in SBF was demonstrated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The biocompatibility of the CS/rGO composites was characterized using methyl thiazole tetrazolium (MTT) assays in vitro. The cell adhesion results showed that human osteoblast cells (hFOB) can adhere to and develop on the CS/rGO composites. In addition, the proliferation rate and alkaline phosphatase (ALP) activity of cells on the CS/rGO composites were improved compared with the pure CS ceramics. These results suggest that calcium silicate/reduced graphene oxide composites are promising materials for biomedical applications.
    Matched MeSH terms: Polymers/chemistry
  12. Fulltext Synthesis, characterisation, and evaluation of a cross-linked disulphide amide-anhydride-containing polymer based on cysteine for colonic drug delivery
    Lim V, Peh KK, Sahudin S
    Int J Mol Sci, 2013;14(12):24670-91.
    PMID: 24351841 DOI: 10.3390/ijms141224670
    The use of disulphide polymers, a low redox potential responsive delivery, is one strategy for targeting drugs to the colon so that they are specifically released there. The objective of this study was to synthesise a new cross-linked disulphide-containing polymer based on the amino acid cysteine as a colon drug delivery system and to evaluate the efficiency of the polymers for colon targeted drug delivery under the condition of a low redox potential. The disulphide cross-linked polymers were synthesised via air oxidation of 1,2-ethanedithiol and 3-mercapto-N-2-(3-mercaptopropionamide)-3-mercapto propionic anhydride (trithiol monomers) using different ratio combinations. Four types of polymers were synthesised: P10, P11, P151, and P15. All compounds synthesised were characterised by NMR, IR, LC-MS, CHNS analysis, Raman spectrometry, SEM-EDX, and elemental mapping. The synthesised polymers were evaluated in chemical reduction studies that were performed in zinc/acetic acid solution. The suitability of each polymer for use in colon-targeted drug delivery was investigated in vitro using simulated conditions. Chemical reduction studies showed that all polymers were reduced after 0.5-1.0 h, but different polymers had different thiol concentrations. The bacterial degradation studies showed that the polymers were biodegraded in the anaerobic colonic bacterial medium. Degradation was most pronounced for polymer P15. This result complements the general consensus that biodegradability depends on the swellability of polymers in an aqueous environment. Overall, these results suggest that the cross-linked disulphide-containing polymers described herein could be used as coatings for drugs delivered to the colon.
    Matched MeSH terms: Polymers/chemistry*
  13. Polydopamine as an intermediate layer for silver and hydroxyapatite immobilisation on metallic biomaterials surface
    Saidin S, Chevallier P, Abdul Kadir MR, Hermawan H, Mantovani D
    Mater Sci Eng C Mater Biol Appl, 2013 Dec 1;33(8):4715-24.
    PMID: 24094179 DOI: 10.1016/j.msec.2013.07.026
    Hydroxyapatite (HA) coated implant is more susceptible to bacterial infection as the micro-structure surface which is beneficial for osseointegration, could also become a reservoir for bacterial colonisation. The aim of this study was to introduce the antibacterial effect of silver (Ag) to the biomineralised HA by utilising a polydopamine film as an intermediate layer for Ag and HA immobilisation. Sufficient catechol groups in polydopamine were required to bind chemically stainless steel 316 L, Ag and HA elements. Different amounts of Ag nanoparticles were metallised on the polydopamine grafted stainless steel by varying the immersion time in silver nitrate solution from 12 to 24 h. Another polydopamine layer was then formed on the metallised film, followed by surface biomineralisation in 1.5 Simulated Body Fluid (SBF) solution for 3 days. Several characterisation techniques including X-Ray Photoelectron Spectroscopy, Atomic Force Microscopy, Scanning Electron Microscopy and Contact Angle showed that Ag nanoparticles and HA agglomerations were successfully immobilised on the polydopamine film through an element reduction process. The Ag metallisation at 24 h has killed the viable bacteria with 97.88% of bactericidal ratio. The Ag was ionised up to 7 days which is crucial to prevent bacterial infection during the first stage of implant restoration. The aged functionalised films were considered stable due to less alteration of its chemical composition, surface roughness and wettability properties. The ability of the functionalised film to coat complex and micro scale metal make it suitable for dental and orthopaedic implants application.
    Matched MeSH terms: Polymers/chemistry*
  14. Removal of 2,4-dichlorophenol using cyclodextrin-ionic liquid polymer as a macroporous material: characterization, adsorption isotherm, kinetic study, thermodynamics
    Raoov M, Mohamad S, Abas MR
    J Hazard Mater, 2013 Dec 15;263 Pt 2:501-16.
    PMID: 24231314 DOI: 10.1016/j.jhazmat.2013.10.003
    Cyclodextrin-ionic liquid polymer (βCD-BIMOTs-TDI) was firstly synthesized using functionalized β-Cyclodextrin (CD) with 1-benzylimidazole (BIM) to form monofunctionalized CD (βCD-BIMOTs) and was further polymerized using toluene diisocyanate (TDI) linker to form insoluble βCD-BIMOTs-TDI. SEM characterization result shows that βCD-BIMOTs-TDI exhibits macropore size while the BET result shows low surface area (1.254 m(2)g(-1)). The unique properties of the ILs allow us to produce materials with different morphologies. The adsorption isotherm and kinetics of 2,4-dichlorophenol (2,4-DCP) onto βCD-BIMOTs-TDI is studied. Freundlich isotherm and pseudo-second order kinetics are found to be the best to represent the data for 2,4-DCP adsorption on the βCD-BIMOTs-TDI. The presence of macropores decreases the mass transfer resistance and increases the adsorption process by reducing the diffusion distance. The change in entropy (ΔS°) and heat of adsorption (ΔH°) for 2,4-DCP on βCD-BIMOTs-TDI were estimated as -55.99 J/Kmol and -18.10 J/mol, respectively. The negative value of Gibbs free energy (ΔG°) indicates that the adsorption process is thermodynamically feasible, spontaneous and chemically controlled. Finally, the interactions between the cavity of βCD-BIMOTs and 2,4-DCP are investigated and the results shows that the inclusion of the complex formation and π-π interaction are the main processes involved in the adsorption process.
    Matched MeSH terms: Polymers/chemistry
  15. Aptamer-Mediated Polymeric Vehicles for Enhanced Cell-Targeted Drug Delivery
    Tan KX, Danquah MK, Sidhu A, Yon LS, Ongkudon CM
    Curr Drug Targets, 2018 02 08;19(3):248-258.
    PMID: 27321771 DOI: 10.2174/1389450117666160617120926
    BACKGROUND: The search for smart delivery systems for enhanced pre-clinical and clinical pharmaceutical delivery and cell targeting continues to be a major biomedical research endeavor owing to differences in the physicochemical characteristics and physiological effects of drug molecules, and this affects the delivery mechanisms to elicit maximum therapeutic effects. Targeted drug delivery is a smart evolution essential to address major challenges associated with conventional drug delivery systems. These challenges mostly result in poor pharmacokinetics due to the inability of the active pharmaceutical ingredients to specifically act on malignant cells thus, causing poor therapeutic index and toxicity to surrounding normal cells. Aptamers are oligonucleotides with engineered affinities to bind specifically to their cognate targets. Aptamers have gained significant interests as effective targeting elements for enhanced therapeutic delivery as they can be generated to specifically bind to wide range of targets including proteins, peptides, ions, cells and tissues. Notwithstanding, effective delivery of aptamers as therapeutic vehicles is challenged by cell membrane electrostatic repulsion, endonuclease degradation, low pH cleavage, and binding conformation stability.

    OBJECTIVE: The application of molecularly engineered biodegradable and biocompatible polymeric particles with tunable features such as surface area and chemistry, particulate size distribution and toxicity creates opportunities to develop smart aptamer-mediated delivery systems for controlled drug release.

    RESULTS: This article discusses opportunities for particulate aptamer-drug formulations to advance current drug delivery modalities by navigating active ingredients through cellular and biomolecular traffic to target sites for sustained and controlled release at effective therapeutic dosages while minimizing systemic cytotoxic effects.

    CONCLUSION: A proposal for a novel drug-polymer-aptamer-polymer (DPAP) design of aptamer-drug formulation with stage-wise delivery mechanism is presented to illustrate the potential efficacy of aptamer- polymer cargos for enhanced cell targeting and drug delivery.

    Matched MeSH terms: Polymers/chemistry
  16. Removal of bisphenol A by adsorption mechanism using PES-SiO2 composite membranes
    Muhamad MS, Salim MR, Lau WJ, Hadibarata T, Yusop Z
    Environ Technol, 2016 Aug;37(15):1959-69.
    PMID: 26729509 DOI: 10.1080/09593330.2015.1137359
    Polyethersulphone (PES) membranes blended with silicon dioxide (SiO2) nanoparticles were prepared via a dry-jet wet spinning technique for the removal of bisphenol A (BPA) by adsorption mechanism. The morphology of SiO2 nanoparticles was analysed using a transmission electron microscopy and particle size distribution was also analysed. The prepared membranes were characterized by several techniques including field emission scanning electron microscopy, Fourier transform infrared spectroscopy and water contact angle. The adsorption mechanism of membrane towards BPA was evaluated by batch experiments and kinetic model. The influence of natural organic matter (NOM) in feed water on membrane BPA removal was also studied by filtration experiments. Results showed that BPA adsorption capacity as high as 53 µg/g could be achieved by the PES membrane incorporated with 2 wt% SiO2 in which the adsorption mechanism was in accordance with the pseudo-second-order kinetic model. The intraparticles diffusion model suggested that the rate limiting factor of membrane adsorption mechanism is governed by the diffusion of BPA into the membrane pores. The presence of 10 ppm NOM has reported to negatively reduce BPA removal by 24%, as it tended to compete with BPA for membrane adsorption. This work has demonstrated that PES-SiO2 membrane has the potential to eliminate trace amount of BPA from water source containing NOM.
    Matched MeSH terms: Polymers/chemistry*
  17. Alginate-based bipolymeric-nanobioceramic composite matrices for sustained drug release
    Hasnain MS, Nayak AK, Singh M, Tabish M, Ansari MT, Ara TJ
    Int J Biol Macromol, 2016 Feb;83:71-7.
    PMID: 26608007 DOI: 10.1016/j.ijbiomac.2015.11.044
    Alginate-based bipolymeric-nanobioceramic composite matrices for sustained drug release were developed through incorporation of nano-hydroxyapatite [nHAp] powders within ionotropically-gelled calcium ion-induced alginate-poly (vinyl pyrrolidone) blends polymeric systems. nHAp powders were synthesized by precipitation technique using calcium hydroxide [Ca(OH)2] and orthophosphoric acid [H3PO4] as raw materials. The average particle size of these was synthesized. nHAp powders was found as 19.04 nm and used to prepare nHAp-alginate-PVP beads containing DS. These beads exhibited drug entrapment efficiency (%) of 65.82±1.88 to 94.45±3.72% and average bead sizes of 0.98±0.07 to 1.23±0.15 mm. These beads were characterized by scanning electron microscopy (SEM) and Fourier transform-infra red (FTIR) spectroscopy analyses. Various nHAp-alginate-PVP beads containing DS exhibited prolonged sustained drug release and followed the Koresmeyer-Peppas model of drug release (R2=0.9908-0.9978) with non-Fickian release (anomalous transport) mechanism (n=0.73-0.84) for drug release over 8 h.
    Matched MeSH terms: Polymers/chemistry*
  18. Fulltext Gamma scintigraphic evaluation of floating gastroretentive tablets of metformin HCl using a combination of three natural polymers in rabbits
    Razavi M, Karimian H, Yeong CH, Chung LY, Nyamathulla S, Noordin MI
    Drug Des Devel Ther, 2015;9:4373-86.
    PMID: 26273196 DOI: 10.2147/DDDT.S86263
    The present research was aimed at formulating a metformin HCl sustained-release formulation from a combination of polymers, using the wet granulation technique. A total of 16 formulations (F1-F16) were produced using different combinations of the gel-forming polymers: tamarind kernel powder, salep (palmate tubers of Orchis morio), and xanthan. Post-compression studies showed that there were no interactions between the active drug and the polymers. Results of in vitro drug-release studies indicated that the F10 formulation which contained 5 mg of tamarind kernel powder, 33.33 mg of xanthan, and 61.67 mg of salep could sustain a 95% release in 12 hours. The results also showed that F2 had a 55% similarity factor with the commercial formulation (C-ER), and the release kinetics were explained with zero order and Higuchi models. The in vivo study was performed in New Zealand White rabbits by gamma scintigraphy; the F10 formulation was radiolabeled using samarium (III) oxide ((153)Sm2O3) to trace transit of the tablets in the gastrointestinal tract. The in vivo data supported the retention of F10 formulation in the gastric region for 12 hours. In conclusion, the use of a combination of polymers in this study helped to develop an optimal gastroretentive drug-delivery system with improved bioavailability, swelling, and floating characteristics.
    Matched MeSH terms: Polymers/chemistry*
  19. Doxorubicin and siRNA Codelivery via Chitosan-Coated pH-Responsive Mixed Micellar Polyplexes for Enhanced Cancer Therapy in Multidrug-Resistant Tumors
    Butt AM, Amin MC, Katas H, Abdul Murad NA, Jamal R, Kesharwani P
    Mol Pharm, 2016 12 05;13(12):4179-4190.
    PMID: 27934479
    This study investigated the potential of chitosan-coated mixed micellar nanocarriers (polyplexes) for codelivery of siRNA and doxorubicin (DOX). DOX-loaded mixed micelles (serving as cores) were prepared by thin film hydration method and coated with chitosan (CS, serving as outer shell), and complexed with multidrug resistance (MDR) inhibiting siRNA. Selective targeting was achieved by folic acid conjugation. The polyplexes showed pH-responsive enhanced DOX release in acidic tumor pH, resulting in higher intracellular accumulation, which was further augmented by downregulation of mdr-1 gene after treatment with siRNA-complexed polyplexes. In vitro cytotoxicity assay demonstrated an enhanced cytotoxicity in native 4T1 and multidrug-resistant 4T1-mdr cell lines, compared to free DOX. Furthermore, in vivo, polyplexes codelivery resulted in highest DOX accumulation and significantly reduced the tumor volume in mice with 4T1 and 4T1-mdr tumors as compared to the free DOX groups, leading to improved survival times in mice. In conclusion, codelivery of siRNA and DOX via polyplexes has excellent potential as targeted drug nanocarriers for treatment of MDR cancers.
    Matched MeSH terms: Polymers/chemistry
  20. Methotrexate and beta-carotene loaded-lipid polymer hybrid nanoparticles: a preclinical study for breast cancer
    Jain A, Sharma G, Kushwah V, Garg NK, Kesharwani P, Ghoshal G, et al.
    Nanomedicine (Lond), 2017 Aug;12(15):1851-1872.
    PMID: 28703643 DOI: 10.2217/nnm-2017-0011
    AIM: This work was intended to investigate the targeting potential of fructose-tethered lipid-polymeric hybrid nanoparticles (F-BC-MTX-LPHNPs) co-loaded with beta carotene (BC) and methotrexate (MTX) in breast cancer therapeutics and find out the possible protective role of BC on MTX-induced toxicity.

    MATERIALS & METHODS: F-BC-MTX-LPHNPs were fabricated using self-assembled nano-precipitation technique. Fructose was conjugated on the surface of the particles. The in vitro cytotoxicity, sub-cellular localization and apoptotic activity of F-BC-MTX-LPHNPs were evaluated against MCF-7 breast cancer cells. The antitumor potential of F-BC-MTX-LPHNPs was further studied.

    RESULTS & CONCLUSION: Outcomes suggested that F-BC-MTX-LPHNPs induced the highest apoptosis index (0.89) against MCF-7 cells. Following 30 days of treatment, the residual tumor progression was assessed to be approximately 32%, in animals treated with F-BC-MTX-LPHNPs. F-BC-MTX-LPHNPs are competent to selectively convey the chemotherapeutic agent to the breast cancers. Beta carotene ameliorated MTX-induced hepatic and renal toxicity.

    Matched MeSH terms: Polymers/chemistry
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