Displaying publications 221 - 240 of 255 in total

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  1. Fulltext Experimental and molecular modeling approach to optimize suitable polymers for fabrication of stable fluticasone nanoparticles with enhanced dissolution and antimicrobial activity
    Ahmed S, Govender T, Khan I, Rehman NU, Ali W, Shah SMH, et al.
    Drug Des Devel Ther, 2018;12:255-269.
    PMID: 29440875 DOI: 10.2147/DDDT.S148912
    Background and aim: The challenges with current antimicrobial drug therapy and resistance remain a significant global health threat. Nanodrug delivery systems are playing a crucial role in overcoming these challenges and open new avenues for effective antimicrobial therapy. While fluticasone (FLU), a poorly water-soluble corticosteroid, has been reported to have potential antimicrobial activity, approaches to optimize its dissolution profile and antimicrobial activity are lacking in the literature. This study aimed to combine an experimental study with molecular modeling to design stable FLU nanopolymeric particles with enhanced dissolution rates and antimicrobial activity.

    Methods: Six different polymers were used to prepare FLU nanopolymeric particles: hydroxyl propyl methylcellulose (HPMC), poly (vinylpyrrolidone) (PVP), poly (vinyl alcohol) (PVA), ethyl cellulose (EC), Eudragit (EUD), and Pluronics®. A low-energy method, nanoprecipitation, was used to prepare the polymeric nanoparticles.

    Results and conclusion: The combination of HPMC-PVP and EUD-PVP was found most effective to produce stable FLU nanoparticles, with particle sizes of 250 nm ±2.0 and 280 nm ±4.2 and polydispersity indices of 0.15 nm ±0.01 and 0.25 nm ±0.03, respectively. The molecular modeling studies endorsed the same results, showing highest polymer drug binding free energies for HPMC-PVP-FLU (-35.22 kcal/mol ±0.79) and EUD-PVP-FLU (-25.17 kcal/mol ±1.12). In addition, it was observed that Ethocel® favored a wrapping mechanism around the drug molecules rather than a linear conformation that was witnessed for other individual polymers. The stability studies conducted for 90 days demonstrated that HPMC-PVP-FLU nanoparticles stored at 2°C-8°C and 25°C were more stable. Crystallinity of the processed FLU nanoparticles was confirmed using differential scanning calorimetry, powder X-ray diffraction analysis and TEM. The Fourier transform infrared spectroscopy (FTIR) studies showed that there was no chemical interaction between the drug and chosen polymer system. The HPMC-PVP-FLU nanoparticles also showed enhanced dissolution rate (P<0.05) compared to the unprocessed counterpart. The in vitro antibacterial studies showed that HPMC-PVP-FLU nanoparticles displayed superior effect against gram-positive bacteria compared to the unprocessed FLU and positive control.

    Matched MeSH terms: Polymers/chemistry*
  2. Investigation on solution-to-gel characteristic of thermosensitive and mucoadhesive biopolymers for the development of moxifloxacin-loaded sustained release periodontal in situ gels
    Sheshala R, Quah SY, Tan GC, Meka VS, Jnanendrappa N, Sahu PS
    Drug Deliv Transl Res, 2019 04;9(2):434-443.
    PMID: 29392681 DOI: 10.1007/s13346-018-0488-6
    The objectives of present research were to develop and characterize thermosensitive and mucoadhesive polymer-based sustained release moxifloxacin in situ gels for the treatment of periodontal diseases. Poloxamer- and chitosan-based in situ gels are in liquid form at room temperature and transform into gel once administered into periodontal pocket due to raise in temperature to 37 °C. Besides solution-to-gel characteristic of polymers, their mucoadhesive nature aids the gel to adhere to mucosa in periodontal pocket for prolonged time and releases the drug in sustained manner. These formulations were prepared using cold method and evaluated for pH, solution-gel temperature, syringeability and viscosity. In vitro drug release studies were conducted using dialysis membrane at 37 °C and 50 rpm. Antimicrobial studies carried out against Aggregatibacter actinomycetemcomitans (A.A.) and Streptococcus mutans (S. Mutans) using agar cup-plate method. The prepared formulations were clear and pH was at 7.01-7.40. The viscosity of formulations was found to be satisfactory. Among the all, formulations comprising of 21% poloxamer 407 and 2% poloxamer 188 (P5) and in combination with 0.5% HPMC (P6) as well as 2% chitosan and 70% β-glycerophosphate (C6) demonstrated an ideal gelation temperature (33-37 °C) and sustained the drug release for 8 h. Formulations P6 and C6 showed promising antimicrobial efficacy with zone of inhibition of 27 mm for A.A. and 55 mm for S. Mutans. The developed sustained release in situ gel formulations could enhance patient's compliance by reducing the dosing frequency and also act as an alternative treatment to curb periodontitis.
    Matched MeSH terms: Polymers/chemistry
  3. Controlled delivery of the antiprotozoal agent (tinidazole) from intravaginal polymer matrices for treatment of the sexually transmitted infection, trichomoniasis
    Fernando HV, Chan LL, Dang N, Santhanes D, Banneheke H, Nalliah S, et al.
    Pharm Dev Technol, 2019 Mar;24(3):348-356.
    PMID: 29799300 DOI: 10.1080/10837450.2018.1481430
    Microporous polymeric matrices prepared from poly(ɛ-caprolactone) [PCL] were evaluated for controlled vaginal delivery of the antiprotozoal agent (tinidazole) in the treatment of the sexually transmitted infection, trichomoniasis. The matrices were produced by rapidly cooling co-solutions of PCL and tinidazole in acetone to -80 °C to induce crystallisation and hardening of the polymer. Tinidazole incorporation in the matrices increased from 1.4 to 3.9% (w/w), when the drug concentration in the starting PCL solution was raised from 10 to 20% (w/w), giving rise to drug loading efficiencies up to 20%. Rapid 'burst release' of 30% of the tinidazole content was recorded over 24 h when the PCL matrices were immersed in simulated vaginal fluid. Gradual drug release occurred over the next 6 days resulting in delivery of around 50% of the tinidazole load by day 7 with the released drug retaining antiprotozoal activity at levels almost 50% that of the 'non-formulated' drug in solution form. Basic modelling predicted that the concentration of tinidazole released into vaginal fluid in vivo from a PCL matrix in the form of an intravaginal ring would exceed the minimum inhibitory concentration against Trichomonas vaginalis. These findings recommend further investigation of PCL matrices as intravaginal devices for controlled delivery of antiprotozoal agents in the treatment and prevention of sexually transmitted infections.
    Matched MeSH terms: Polymers/chemistry
  4. Fabrication and characterization of matrix type transdermal patches loaded with tizanidine hydrochloride: potential sustained release delivery system
    Shahid N, Siddique MI, Razzaq Z, Katas H, Waqas MK, Rahman KU
    Drug Dev Ind Pharm, 2018 Dec;44(12):2061-2070.
    PMID: 30081679 DOI: 10.1080/03639045.2018.1509081
    OBJECTIVE: This study was designed to optimize and develop matrix type transdermal drug delivery system (TDDS) containing tizanidine hydrochloride (TZH) using different polymers by solvent evaporation method.

    SIGNIFICANCE: A strong need exists for the development of transdermal patch having improved bioavailability at the site of action with fewer side effects at off-target organs.

    METHODS: The patches were physically characterized by texture analysis (color, flexibility, smoothness, transparency, and homogeneity), in vitro dissolution test and FTIR analysis. Furthermore, functional properties essential for TDDS, in vitro percentage of moisture content, percentage of water uptake, in vitro permeation by following different kinetic models, in vivo drug content estimation and skin irritation were determined using rabbit skin.

    RESULTS: The optimized patches were soft, of uniform texture and thickness as well as pliable in nature. Novel transdermal patch showed ideal characteristics in terms of moisture content and water uptake. FTIR analysis confirmed no interaction between TZH and cellulose acetate phthalate (CAP). The patch showed sustained release of the drug which increased the availability of short acting TZH at the site of action. The patch also showed its biocompatibility to the in vivo model of rabbit skin.

    CONCLUSIONS: The results demonstrated that topically applied transdermal patch will be a potential medicated sustain release patch for muscle pain which will improve patient compliance.

    Matched MeSH terms: Polymers/chemistry
  5. Hydrous ferric oxide nanoparticles hosted porous polyethersulfone adsorptive membrane: chromium (VI) adsorptive studies and its applicability for water/wastewater treatment
    Abdullah N, Yusof N, Abu Shah MH, Wan Ikhsan SN, Ng ZC, Maji S, et al.
    Environ Sci Pollut Res Int, 2019 Jul;26(20):20386-20399.
    PMID: 31102226 DOI: 10.1007/s11356-019-05208-9
    In this present study, adsorptive membranes for Cr(VI) ion removal were prepared by blending polyethersulfone (PES) with hydrous ferric oxide (HFO) nanoparticles (NPs). The effects of HFO NPs to PES weight ratio (0-1.5) on the physicochemical properties of the resultant HFO/PES adsorptive membranes were investigated with respect to the surface chemistry and roughness as well as structural morphologies using different analytical instruments. The adsorptive performance of the HFO NPs/PES membranes was studied via batch adsorption experiments under various conditions by varying solution pH, initial concentration of Cr(VI), and contact time. The results showed that the membrane made of HFO/PES at a weight ratio of 1.0 exhibited the highest adsorption capacity which is 13.5 mg/g. Isotherm and kinetic studies revealed that the mechanism is best fitted to the Langmuir model and pseudo-second-order model. For filtration of Cr(VI), the best promising membranes showed improved water flux (629.3 L/m2 h) with Cr(VI) ion removal of 75%. More importantly, the newly developed membrane maintained the Cr(VI) concentration below the maximum contamination level (MCL) for up to 9 h.
    Matched MeSH terms: Polymers/chemistry
  6. Elastomeric biocomposite of silver-containing mesoporous bioactive glass and poly(1,8-octanediol citrate): Physiochemistry and in vitro antibacterial capacity in tissue engineering applications
    Pourshahrestani S, Zeimaran E, Kadri NA, Gargiulo N, Jindal HM, Hasikin K, et al.
    Mater Sci Eng C Mater Biol Appl, 2019 May;98:1022-1033.
    PMID: 30812986 DOI: 10.1016/j.msec.2019.01.022
    A novel series of silver-doped mesoporous bioactive glass/poly(1,8-octanediol citrate) (AgMBG/POC) elastomeric biocomposite scaffolds were successfully constructed by a salt-leaching technique for the first time and the effect of inclusion of different AgMBG contents (5, 10, and 20 wt%) on physicochemical and biological properties of pure POC elastomer was evaluated. Results indicated that AgMBG particles were uniformly dispersed in the POC matrix and increasing the AgMBG concentration into POC matrix up to 20 wt% enhanced thermal behaviour, mechanical properties and water uptake ability of the composite scaffolds compared to those from POC. The 20%AgMBG/POC additionally showed higher degradation rate in Tris(hydroxymethyl)-aminomethane-HCl (Tris-HCl) compared with pure POC and lost about 26% of its initial weight after soaking for 28 days. The AgMBG phase incorporation also significantly endowed the resulting composite scaffolds with efficient antibacterial properties against Escherichia coli and Staphylococcus aureus bacteria while preserving their favorable biocompatibility with soft tissue cells (i.e., human dermal fibroblast cells). Taken together, our results suggest that the synergistic effect of both AgMBG and POC make these newly designed AgMBG/POC composite scaffold an attractive candidate for soft tissue engineering applications.
    Matched MeSH terms: Polymers/chemistry*
  7. Sulfur and nitrogen containing plasma polymers reduces bacterial attachment and growth
    Siow KS, Abdul Rahman AS, Ng PY, Majlis BY
    Mater Sci Eng C Mater Biol Appl, 2020 Feb;107:110225.
    PMID: 31761201 DOI: 10.1016/j.msec.2019.110225
    Role of sulfur (S) and nitrogen (N) groups in promoting cell adhesion or commonly known as biocompatibility, is well established, but their role in reducing bacterial attachment and growth is less explored or not well-understood. Natural sulfur-based compounds, i.e. sulfide, sulfoxide and sulfinic groups, have shown to inhibit bacterial adhesion and biofilm formation. Hence, we mimicked these surfaces by plasma polymerizing thiophene (ppT) and air-plasma treating this ppT to achieve coatings with S of similar oxidation states as natural compounds (ppT-air). In addition, the effects of these N and S groups from ppT-air were also compared with the biocompatible amine-amide from n-heptylamine plasma polymer. Crystal violet assay and live and dead fluorescence staining of E. coli and S. aureus showed that all the N and S coated surfaces generated, including ppHA, ppT and ppT-air, produced similarly potent, growth reduction of both bacteria by approximately 65% at 72 h compared to untreated glass control. The ability of osteogenic differentiation in Wharton's jelly mesenchymal stem cells (WJ-MSCs) were also used to test the cell biocompatibility of these surfaces. Alkaline phosphatase assay and scanning electron microscopy imaging of these WJ-MSCs growths indicated that ppHA, and ppT-air were cell-friendly surfaces, with ppHA showing the highest osteogenic activity. In summary, the N and S containing surfaces could reduce bacteria growth while promoting mammalian cell growth, thus serve as potential candidate surfaces to be explored further for biomaterial applications.
    Matched MeSH terms: Polymers/chemistry*
  8. Molecular insights and novel approaches for targeting tumor metastasis
    Das SS, Alkahtani S, Bharadwaj P, Ansari MT, ALKahtani MDF, Pang Z, et al.
    Int J Pharm, 2020 Jul 30;585:119556.
    PMID: 32574684 DOI: 10.1016/j.ijpharm.2020.119556
    In recent years, due to the effective drug delivery and preciseness of tumor sites or microenvironment, the targeted drug delivery approaches have gained ample attention for tumor metastasis therapy. The conventional treatment approaches for metastasis therapy have reported with immense adverse effects because they exhibited maximum probability of killing the carcinogenic cells along with healthy cells. The tumor vasculature, comprising of vasculogenic impressions and angiogenesis, greatly depends upon the growth and metastasis in the tumors. Therefore, various nanocarriers-based delivery approaches for targeting to tumor vasculature have been attempted as efficient and potential approaches for the treatment of tumor metastasis and the associated lesions. Furthermore, the targeted drug delivery approaches have found to be most apt way to overcome from all the limitations and adverse effects associated with the conventional therapies. In this review, various approaches for efficient targeting of pharmacologically active chemotherapeutics against tumor metastasis with the cohesive objectives of prognosis, tracking and therapy are summarized.
    Matched MeSH terms: Polymers/chemistry
  9. Fulltext Surface functionalisation of poly-APO-b-polyol ester cross-linked copolymers as core-shell nanoparticles for targeted breast cancer therapy
    Tajau R, Rohani R, Abdul Hamid SS, Adam Z, Mohd Janib SN, Salleh MZ
    Sci Rep, 2020 12 10;10(1):21704.
    PMID: 33303818 DOI: 10.1038/s41598-020-78601-x
    Polymeric nanoparticles (NPs) are commonly used as nanocarriers for drug delivery, whereby their sizes can be altered for a more efficient delivery of therapeutic active agents with better efficacy. In this work, cross-linked copolymers acted as core-shell NPs from acrylated palm olein (APO) with polyol ester were synthesized via gamma radiation-induced reversible addition-fragmentation chain transfer (RAFT) polymerisation. The particle diameter of the copolymerised poly(APO-b-polyol ester) core-shell NPs was found to be less than 300 nm, have a low molecular weight (MW) of around 24 kDa, and showed a controlled MW distribution of a narrow polydispersity index (PDI) of 1.01. These properties were particularly crucial for further use in designing targeted NPs, with inclusion of peptide for the targeted delivery of paclitaxel. Moreover, the characterisation of the synthesised NPs using Fourier Transform-Infrared (FTIR) and Neutron Magnetic Resonance (NMR) analyses confirmed the possession of biodegradable hydrolysed ester in its chemical structures. Therefore, it can be concluded that the synthesised NPs produced may potentially contribute to better development of a nano-structured drug delivery system for breast cancer therapy.
    Matched MeSH terms: Polymers/chemistry
  10. Fulltext Combating Intracellular Pathogens with Nanohybrid-Facilitated Antibiotic Delivery
    Bose RJC, Tharmalingam N, Choi Y, Madheswaran T, Paulmurugan R, McCarthy JR, et al.
    Int J Nanomedicine, 2020;15:8437-8449.
    PMID: 33162754 DOI: 10.2147/IJN.S271850
    BACKGROUND: Lipid polymer hybrid nanoparticles (LPHNPs) have been widely investigated in drug and gene delivery as well as in medical imaging. A knowledge of lipid-based surface engineering and its effects on how the physicochemical properties of LPHNPs affect the cell-nanoparticle interactions, and consequently how it influences the cytological response, is in high demand.

    METHODS: Herein, we have engineered antibiotic-loaded (doxycycline or vancomycin) LPHNPs with cationic and zwitterionic lipids and examined the effects on their physicochemical characteristics (size and charge), antibiotic entrapment efficiency, and the in vitro intracellular bacterial killing efficiency against Mycobacterium smegmatis or Staphylococcus aureus infected macrophages.

    RESULTS: The incorporation of cationic or zwitterionic lipids in the LPHNP formulation resulted in a size reduction in LPHNPs formulations and shifted the surface charge of bare NPs towards positive or neutral values. Also observed were influences on the drug incorporation efficiency and modulation of the drug release from the biodegradable polymeric core. The therapeutic efficacy of LPHNPs loaded with vancomycin was improved as its minimum inhibitory concentration (MIC) (2 µg/mL) versus free vancomycin (4 µg/mL). Importantly, our results show a direct relationship between the cationic surface nature of LPHNPs and its intracellular bacterial killing efficiency as the cationic doxycycline or vancomycin loaded LPHNPs reduced 4 or 3 log CFU respectively versus the untreated controls.

    CONCLUSION: In our study, modulation of surface charge in the nanomaterial formulation increased macrophage uptake and intracellular bacterial killing efficiency of LPHNPs loaded with antibiotics, suggesting alternate way for optimizing their use in biomedical applications.

    Matched MeSH terms: Polymers/chemistry
  11. Nanoencapsulation, an efficient and promising approach to maximize wound healing efficacy of curcumin: A review of new trends and state-of-the-art
    Hussain Z, Thu HE, Ng SF, Khan S, Katas H
    Colloids Surf B Biointerfaces, 2017 Feb 01;150:223-241.
    PMID: 27918967 DOI: 10.1016/j.colsurfb.2016.11.036
    Wound healing is a multifarious and vibrant process of replacing devitalized and damaged cellular structures, leading to restoration of the skin's barrier function, re-establishment of tissue integrity, and maintenance of the internal homeostasis. Curcumin (CUR) and its analogs have gained widespread recognition due to their remarkable anti-inflammatory, anti-infective, anticancer, immunomodulatory, antioxidant, and wound healing activities. However, their pharmaceutical significance is limited due to inherent hydrophobic nature, poor water solubility, low bioavailability, chemical instability, rapid metabolism and short half-life. Owing to their pharmaceutical limitations, newer strategies have been attempted in recent years aiming to mitigate problems related to the effective delivery of curcumanoids and to improve their wound healing potential. These advanced strategies include nanovesicles, polymeric micelles, conventional liposomes and hyalurosomes, nanocomposite hydrogels, electrospun nanofibers, nanohybrid scaffolds, nanoconjugates, nanostructured lipid carriers (NLCs), nanoemulsion, nanodispersion, and polymeric nanoparticles (NPs). The superior wound healing activities achieved after nanoencapsulation of the CUR are attributed to its target-specific delivery, longer retention at the target site, avoiding premature degradation of the encapsulated cargo and the therapeutic superiority of the advanced delivery systems over the conventional delivery. We have critically reviewed the literature and summarize the convincing evidence which explore the pharmaceutical significance and therapeutic feasibility of the advanced delivery systems in improving wound healing activities of the CUR and its analogs.
    Matched MeSH terms: Polymers/chemistry
  12. Application of diverse natural polymers in the design of oral gels for the treatment of periodontal diseases
    Ganguly A, Ian CK, Sheshala R, Sahu PS, Al-Waeli H, Meka VS
    J Mater Sci Mater Med, 2017 Mar;28(3):39.
    PMID: 28144851 DOI: 10.1007/s10856-017-5852-4
    The objective of this study was to prepare periodontal gels using natural polymers such as badam gum, karaya gum and chitosan. These gels were tested for their physical and biochemical properties and assessed for their antibacterial activity against Aggregatibacter actinomycetemcomitans and Streptococcus mutans, two pathogens associated with periodontal disease. Badam gum, karaya gum and chitosan were used to prepare gels of varying concentrations. Moxifloxacin hydrochloride, a known antimicrobial drug was choosen in the present study and it was added to the above gels. The gels were then run through a battery of tests in order to determine their physical properties such as pH and viscosity. Diffusion studies were carried out on the gels containing the drug. Antimicrobial testing of the gels against various bacteria was then carried out to determine the effectiveness of the gels against these pathogens. The results showed that natural polymers can be used to produce gels. These gels do not have inherent antimicrobial properties against A. actinomycetemcomitans and S. mutans. However, they can be used as a transport vehicle to carry and release antimicrobial drugs.
    Matched MeSH terms: Polymers/chemistry
  13. Some mechanical properties of a highly cross-linked, microwave-polymerized, injection-molded denture base polymer
    Memon MS, Yunus N, Razak AA
    Int J Prosthodont, 2001 May-Jun;14(3):214-8.
    PMID: 11484567
    PURPOSE: The impact strength and the flexural properties of denture base materials are of importance in predicting their clinical performance upon sudden loading. This study compares the impact and transverse strengths and the flexural modulus of three denture base polymers.
    MATERIALS AND METHODS: The investigation included a relatively new microwave-polymerized polyurethane-based denture material processed by an injection-molding technique, a conventional microwave-polymerized denture material, and a heat-polymerized compression-molded poly(methyl methacrylate) (PMMA) denture material. Impact strength was determined using a Charpy-type impact tester. The transverse strength and the flexural modulus were assessed with a three-point bending test. The results were subjected to statistical analysis using a one-way analysis of variance and the Scheffé test for comparison.
    RESULTS: The impact strength of the microwave-polymerized injection-molded polymer was 6.3 kl/m2, while its flexural strength was 66.2 MPa. These values were lower than those shown by the two compression-molded PMMA-based polymers. The differences were statistically significant. The flexural modulus of the new denture material was 2,832 MPa, which was higher than the conventional heat-polymerized polymer but was comparable to the other microwave-polymerized PMMA-based polymer. The difference in the flexural modulus was statistically significant.
    CONCLUSION: In terms of the impact and flexural strengths, the new microwave-polymerized, injection-molded, polyurethane-based polymer offered no advantage over the existing heat- and microwave-polymerized PMMA-based denture base polymers. However, it has a rigidity comparable to that of the microwave-polymerized PMMA polymer.
    Matched MeSH terms: Polymers/chemistry*
  14. Formulation and evaluation of controlled release Eudragit buccal patches
    Wong CF, Yuen KH, Peh KK
    Int J Pharm, 1999 Feb 01;178(1):11-22.
    PMID: 10205621
    Controlled release buccal patches were fabricated using Eudragit NE40D and studied. Various bioadhesive polymers, namely hydroxypropylmethyl cellulose, sodium carboxymethyl cellulose and Carbopol of different grades, were incorporated into the patches, to modify their bioadhesive properties as well as the rate of drug release, using metoprolol tartrate as the model drug. The in-vitro drug release was determined using the USP 23 dissolution test apparatus 5 with slight modification, while the bioadhesive properties were evaluated using texture analyzer equipment with chicken pouch as the model tissue. The incorporation of hydrophilic polymers was found to affect the drug release as well as enhance the bioadhesiveness. Although high viscosity polymers can enhance the bioadhesiveness of the patches, they also tend to cause non-homogeneous distribution of the polymers and drug, resulting in non-predictable drug-release rates. Of the various bioadhesive polymers studied, Cekol 700 appeared to be most satisfactory in terms of modifying the drug release and enhancement of the bioadhesive properties.
    Matched MeSH terms: Polymers/chemistry*
  15. Fulltext Revolutionizing polymer-based nanoparticle-linked vaccines for targeting respiratory viruses: A perspective
    Chan Y, Ng SW, Singh SK, Gulati M, Gupta G, Chaudhary SK, et al.
    Life Sci, 2021 Sep 01;280:119744.
    PMID: 34174324 DOI: 10.1016/j.lfs.2021.119744
    Viral respiratory tract infections have significantly impacted global health as well as socio-economic growth. Respiratory viruses such as the influenza virus, respiratory syncytial virus (RSV), and the recent SARS-CoV-2 infection (COVID-19) typically infect the upper respiratory tract by entry through the respiratory mucosa before reaching the lower respiratory tract, resulting in respiratory disease. Generally, vaccination is the primary method in preventing virus pathogenicity and it has been shown to remarkably reduce the burden of various infectious diseases. Nevertheless, the efficacy of conventional vaccines may be hindered by certain limitations, prompting the need to develop novel vaccine delivery vehicles to immunize against various strains of respiratory viruses and to mitigate the risk of a pandemic. In this review, we provide an insight into how polymer-based nanoparticles can be integrated with the development of vaccines to effectively enhance immune responses for combating viral respiratory tract infections.
    Matched MeSH terms: Polymers/chemistry*
  16. Fulltext The anti-proliferative effects of a palm oil-derived product and its mode of actions in human malignant melanoma MeWo cells
    Komarasamy TV, Sekaran SD
    J Oleo Sci, 2012;61(4):227-39.
    PMID: 22450124
    Melanoma incidence and mortality have risen dramatically in recent years. No effective treatment for metastatic melanoma exists; hence currently, an intense effort for new drug evaluation is being carried out. In this study, we investigated the effects of a palm oil-derived nanopolymer called Bio-12 against human malignant melanoma. The nanopolymers of Bio-12 are lipid esters derived from a range of fatty acids of palm oil. Our study aims to identify the anti-proliferative properties of Bio-12 against human malignant melanoma cell line (MeWo) and to elucidate the mode of actions whereby Bio-12 brings about cell death. Bio-12 significantly inhibited the growth of MeWo cells in a concentration- and time- dependent manner with a median inhibitory concentration (IC₅₀) value of 1/25 dilution after 72 h but was ineffective on human normal skin fibroblasts (CCD-1059sk). We further investigated the mode of actions of Bio-12 on MeWo cells. Cell cycle flow cytometry demonstrated that MeWo cells treated with increasing concentrations of Bio-12 resulted in S-phase arrest, accompanied by the detection of sub-G1 content, indicative of apoptotic cell death. Induction of apoptosis was further confirmed via caspase (substrate) cleavage assay which showed induction of early apoptosis in MeWo cells. In addition, DNA strand breaks which are terminal event in apoptosis were evident through increase of TUNEL positive cells and formation of a characteristic DNA ladder on agarose gel electrophoresis. Moreover, treatment of MeWo cells with Bio-12 induced significant increase in lactate dehydrogenase (LDH) activity. These results show that Bio-12 possesses the ability to suppress proliferation of human malignant melanoma MeWo cells and this suppression is at least partly attributed to the initiation of the S-phase arrest, apoptosis and necrosis, suggesting that it is indeed worth for further investigations.
    Matched MeSH terms: Polymers/chemistry
  17. Fulltext Enhancement of mechanical and thermal properties of oil palm empty fruit bunch fiber poly(butylene adipate-co-terephtalate) biocomposites by matrix esterification using succinic anhydride
    Siyamak S, Ibrahim NA, Abdolmohammadi S, Yunus WM, Rahman MZ
    Molecules, 2012 Feb 16;17(2):1969-91.
    PMID: 22343368 DOI: 10.3390/molecules17021969
    In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (Ecoflex™), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites' performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence and absence of dicumyl peroxide (DCP) and benzoyl peroxide (BPO) as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt %) and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA). Scanning Electron Microscopy (SEM) was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR) spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt %) of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt %) succinic anhydride (SAH) and 1 (wt %) dicumyl peroxide (DCP) improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites' spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite.
    Matched MeSH terms: Polymers/chemistry*
  18. Long term mesenchymal stem cell culture on a defined synthetic substrate with enzyme free passaging
    Duffy CR, Zhang R, How SE, Lilienkampf A, De Sousa PA, Bradley M
    Biomaterials, 2014 Jul;35(23):5998-6005.
    PMID: 24780167 DOI: 10.1016/j.biomaterials.2014.04.013
    Mesenchymal stems cells (MSCs) are currently the focus of numerous therapeutic approaches in tissue engineering/repair because of their wide multi-lineage potential and their ability to modulate the immune system response following transplantation. Culturing these cells, while maintaining their multipotency in vitro, currently relies on biological substrates such as gelatin, collagen and fibronectin. In addition, harvesting cells from these substrates requires enzymatic or chemical treatment, a process that will remove a multitude of cellular surface proteins, clearly an undesirable process if cells are to be used therapeutically. Herein, we applied a high-throughput 'hydrogel microarray' screening approach to identify thermo-modulatable substrates which can support hES-MP and ADMSC growth, permit gentle reagent free passaging, whilst maintaining multi-lineage potential. In summary, the hydrogel substrate identified, poly(AEtMA-Cl-co-DEAA) cross-linked with MBA, permitted MSCs to be maintained over 10 passages (each time via thermo-modulation), with the cells retaining expression of MSC associated markers and lineage potency. This chemically defined system allowed the passaging and maintenance of cellular phenotype of this clinically important cell type, in the absence of harsh passaging and the need for biological substrates.
    Matched MeSH terms: Polymers/chemistry
  19. Effect of polymer, plasticizer and filler on orally disintegrating film
    Liew KB, Tan YT, Peh KK
    Drug Dev Ind Pharm, 2014 Jan;40(1):110-9.
    PMID: 23311593 DOI: 10.3109/03639045.2012.749889
    Difficulty in swallowing tablets or capsules has been identified as one of the contributing factors to non-compliance of geriatric patients. Although orally disintegrating tablet was designed for fast disintegration in mouth, the fear of taking solid tablets and the risk of choking for certain patient populations still exist.
    Matched MeSH terms: Polymers/chemistry*
  20. Thermal sintering: a novel technique used in the design, optimization and biopharmaceutical evaluation of propranolol HCl gastric floating tablets
    Venkata Srikanth M, Songa AS, Nali SR, Battu JR, Kolapalli VR
    Drug Dev Ind Pharm, 2014 Jan;40(1):33-45.
    PMID: 23317339 DOI: 10.3109/03639045.2012.744416
    The objective of the present investigation was to study the applicability of thermal sintering technique for the development of gastric floating tablets of propranolol HCl. Formulations were prepared using four independent variables, namely (i) polymer quantity, (ii) sodium bicarbonate concentration, (iii) sintering temperature and (iv) sintering time. Floating lag time and t95 were taken as dependent variables. Tablets were prepared by the direct compression method and were evaluated for physicochemical properties, in vitro buoyancy and dissolution studies. From the drug release studies, it was observed that drug retarding property mainly depends upon the sintering temperature and time of exposure. The statistically optimized formulation (PTSso) was characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry studies, and no significant chemical interaction between drug and polymer was observed. Optimized formulation was stable at accelerated conditions for a period of six months. PTSso was evaluated for in vivo buoyancy studies in humans for both fed and fasted states and found that gastric residence time of the floating tablets were enhanced by fed stage but not in fasted state. Optimized formulation PTSso and commercial formulation Ciplar LA 80 were subjected to bioavailability studies in healthy human volunteers by estimating pharmacokinetic parameters such as Cmax, Tmax, area under curve (AUC), elimination rate constant (Kel), biological half-life (t1/2) and mean residence time (MRT). There was a significant increase in the bioavailability of the propranolol HCl from PTSso formulation, which was evident from increased AUC levels and larger MRT values than Ciplar LA 80.
    Matched MeSH terms: Polymers/chemistry*
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