The Experts below are selected from a list of 1650 Experts worldwide ranked by ideXlab platform
Shuji Sakohara - One of the best experts on this subject based on the ideXlab platform.
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A Novel Thermosensitive Gel Adsorbent for Phosphate Ions
Macromolecular Symposia, 2010Co-Authors: Takehiko Gotoh, Kazunari Tanaka, Takuya Arase, Shuji SakoharaAbstract:A novel Thermosensitive Gel adsorbent for phosphate ions was developed and its adsorption/desorption properties were investigated. The Gel adsorbent was made by the copolymerization of N-isopropylacrylamide (NIPA) and N-[ 3 -(dimethylamino)propyl]acrylamide (DMAPAA). The adsorbent has a volume phase transition temperature (VPTT), below which it becomes hydrophilic. The tertiary amino groups of DMAPAA were ionized and showed a cationic state when the Gel swelled. Phosphate ions were adsorbed onto the ionized tertiary amino groups in the Gel network below the VPTT and were desorbed above the VPTT because of the suppression of the ionization of the tertiary amino groups of Gel and the shrinkage of the Gel.
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Work of adhesion as a dominant factor in formation of composition-gradient Thermosensitive Gel
Chemical Engineering & Technology, 2007Co-Authors: Hideaki Tokuyama, Masahiro Sasaki, Shuji SakoharaAbstract:By copolymerizing a Thermosensitive primary component, N-isopropylacrylamide (NIPA), and an ionic secondary component, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) between two substrates of hydrophilic glass and hydrophobic polytetrafluoroethylene (Teflon), a novel composition-gradient copolymer Gel, in which the AMPS content decreases gradually towards Teflon, is prepared. The formation of the composition-gradient in NIPA-co-AMPS Gels is discussed in terms of the work of adhesion between a solution and a substrate, i.e., the liquid-solid interfacial free energy. The work of adhesion is determined from the Young-Dupre equation on the basis of the measured contact angle and the surface tension in the system consisting of an aqueous solution containing NIPA or AMPS monomers or polymers and glass or Teflon as the substrate. The values of the work of adhesion of AMPS monomer and polymer on Teflon were lower than those on glass. Thus, AMPS remains relatively stable at the glass interface and unstable at the Teflon interface. This repulsion of AMPS due to the hydrophobicity of the Teflon wall generates the composition-gradient.
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Preparation of a novel composition-gradient Thermosensitive Gel
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2005Co-Authors: Hideaki Tokuyama, Masahiro Sasaki, Shuji SakoharaAbstract:Abstract The feasibility of a novel composition-gradient copolymer Gel, in which the composition gradually changes with the distance, was examined. The slab-shaped copolymer Gels of a Thermosensitive primary component, N- isopropylacrylamide (NIPA) and an ionic secondary component, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) or acrylic acid (AA), were prepared between two substrates of hydrophilic glass and hydrophobic polytetrafluoroethylene (Teflon). In the NIPA- co -AMPS Gels, prepared at 40 °C between glass and Teflon, the content of AMPS gradually decreased toward Teflon wall. The formation of the gradient composition can be attributed to the repulsion of hydrophilic AMPS to Teflon. The composition-gradient NIPA- co -AMPS Gel bended and stretched reversibly without breaking in response to the change in temperature. On the other hand, in the NIPA- co -AA Gels prepared at 40 °C between glass and Teflon, AA distributed homogeneously. The difference in the distributions of ionic components in NIPA- co -AA and NIPA- co -AMPS Gels comes from the differences in the reactivities and interactions of the ionic components with NIPA. The conversion of ionic components and the rate of Gelation of NIPA- co -AA are larger than those of NIPA- co -AMPS. The glass transition temperatures of NIPA- co -AA Gels are higher than those of NIPA and AA Gels. This fact is attributed to that NIPA and AA in the copolymer Gels are strongly interacting by hydrogen bonding with amide and carboxylic groups. The essential points to prepare a composition-gradient copolymer Gel are that in addition to the repulsion to a substrate the secondary component has little interaction with the primary component.
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equilibrium and kinetics for temperature swing adsorption of a target metal on molecular imprinted Thermosensitive Gel adsorbents
Separation and Purification Technology, 2005Co-Authors: Hideaki Tokuyama, Ryoichi Kanazawa, Shuji SakoharaAbstract:Abstract A novel Thermosensitive Gel adsorbent, which adsorbs and/or desorbs a specific heavy metal, as a function of Gel shrinking/swelling by temperature swing was developed. The Gel, a copolymer of N -isopropylacrylamide as a Thermosensitive component, 4-(vinylbenzyl)ethylenediamine (VBEDA) as a chelating agent, and cross-linker, was prepared by copolymerization by means of a molecular imprinting technique using Cu(II) ion as a template. Equilibria and kinetics for the adsorption/desorption for a temperature swing of 307/283 K were investigated. Adsorption equilibria, expressed as the Langmuir isotherms, indicated that one Cu molecule is strongly coordinated to two VBEDA groups at 307 K and weakly coordinated to one VBEDA group at 283 K. The rates of adsorption and desorption were dominantly expressed with the diffusion equation within the Gel and were evaluated in terms of effective diffusivity. The equilibria and kinetics data shows the Thermosensitive reconstruction/destruction of an adsorption site composed of two VBEDA groups.
Ameeduzzafar Zafar - One of the best experts on this subject based on the ideXlab platform.
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soy isoflavone loaded alginate microspheres in Thermosensitive Gel base attempts to improve wound healing efficacy
Journal of Pharmacy and Pharmacology, 2019Co-Authors: Mohammed Elmowafy, Khaled Shalaby, Ayman Salama, Ghareb M. Soliman, Nabil K. Alruwaili, Ehab M Mostafa, Elshaer F Mohammed, Abd El Ghany A. Moustafa, Ameeduzzafar ZafarAbstract:Objectives This study aims to develop Thermosensitive Gel containing soy isoflavone (antioxidant and anti-inflammatory natural agent) alginate microspheres for enhancement of wound-healing performance. Methods Soy isoflavone microspheres were prepared by ionic cross-linking method and optimized using the Box-Behnken optimization design. Formulations were characterized in terms of particle size, encapsulation efficiency and equilibrium swelling degree. The optimized formula was incorporated in Pluronic F127 Gel base and examined for in vivo wound-healing efficacy. Key findings Results showed mean particle size between 18 and 25 μm, encapsulation efficiency of over 75% and equilibrium swelling degree over 1.9. Thermal analysis indicated interaction between alginate and CaCl2 and embedding of soy isoflavone in microspheres. In vivo wound-healing efficacy showed significant advance in re-epithelization, mature collagen synthesis and proangiogenesis. Immunohistochemical investigation exhibited promising alpha-smooth muscle actin immunopositive cells expression, fibroblast activation and expression of proliferating cell nuclear antigen (proliferation marker) in the epidermis and in the dermis. Conclusions The developed formulation would appear to be a promising topical preparation for accelerating healing process.
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Soy isoflavone‐loaded alginate microspheres in Thermosensitive Gel base: attempts to improve wound‐healing efficacy
The Journal of pharmacy and pharmacology, 2019Co-Authors: Mohammed Elmowafy, Khaled Shalaby, Ayman Salama, Ghareb M. Soliman, Nabil K. Alruwaili, Ehab M Mostafa, Elshaer F Mohammed, Abd El Ghany A. Moustafa, Ameeduzzafar ZafarAbstract:Objectives This study aims to develop Thermosensitive Gel containing soy isoflavone (antioxidant and anti-inflammatory natural agent) alginate microspheres for enhancement of wound-healing performance. Methods Soy isoflavone microspheres were prepared by ionic cross-linking method and optimized using the Box-Behnken optimization design. Formulations were characterized in terms of particle size, encapsulation efficiency and equilibrium swelling degree. The optimized formula was incorporated in Pluronic F127 Gel base and examined for in vivo wound-healing efficacy. Key findings Results showed mean particle size between 18 and 25 μm, encapsulation efficiency of over 75% and equilibrium swelling degree over 1.9. Thermal analysis indicated interaction between alginate and CaCl2 and embedding of soy isoflavone in microspheres. In vivo wound-healing efficacy showed significant advance in re-epithelization, mature collagen synthesis and proangiogenesis. Immunohistochemical investigation exhibited promising alpha-smooth muscle actin immunopositive cells expression, fibroblast activation and expression of proliferating cell nuclear antigen (proliferation marker) in the epidermis and in the dermis. Conclusions The developed formulation would appear to be a promising topical preparation for accelerating healing process.
Yaou Zhang - One of the best experts on this subject based on the ideXlab platform.
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a Thermosensitive Gel based on w1 o w2 multiple microemulsions for the vaginal delivery of small nucleic acid
Drug Delivery, 2019Co-Authors: Jiu Wang, Yajing Wang, Ziqiang Wang, Fan Wang, Xiaoyun Yang, Weidong Xie, Ying Liu, Yaou ZhangAbstract:The present study aims at designing a Thermosensitive Gel prepared from w1/o/w2 multiple microemulsions (MMEs) for the vaginal delivery of siRNA. The w1/o/w2 MMEs were prepared by two-step emulsifications: the first step was to prepare primary emulsions (w1/o) by low energy emulsification (LEE); the second step was to obtain stable w1/o/w2 MMEs by self-emulsifying. An extensive formulation optimization process was undertaken. The final w1/o/w2 MMEs could be formed in ddH2O, phosphate buffer solution (PBS, pH 7.4) and 1640 culture media with diameter size about 166.5 ± 13.1, 271.0 ± 11.1 and 278.7 ± 12.1 nm respectively. The release rates of siRNA from solutions, MMEs and MMEs-Gels were completed within 2 h, 6 h and13 h respectively. The transfection efficiency of MMEs was confirmed both in vitro and in vivo. The relative target gene expressions of MMEs were 0.07 ± 0.05% vs. 0.37 ± 0.06% in Hela cells against Lipofectamine2000® and 1.88% ± 0.00% vs. 9.65% ± 0.02% in mouse vaginal mucosa against PEI. Good biocompatibility of MMEs was verified by cytotoxicity and pathological studies. Overall, our results indicated the potential of the MMEs-Gel system for the vaginal delivery of siRNA.
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A Thermosensitive Gel based on w1/o/w2 multiple microemulsions for the vaginal delivery of small nucleic acid.
Drug delivery, 2019Co-Authors: Jiu Wang, Yajing Wang, Ziqiang Wang, Fan Wang, Xiaoyun Yang, Weidong Xie, Ying Liu, Yaou ZhangAbstract:The present study aims at designing a Thermosensitive Gel prepared from w1/o/w2 multiple microemulsions (MMEs) for the vaginal delivery of siRNA. The w1/o/w2 MMEs were prepared by two-step emulsifications: the first step was to prepare primary emulsions (w1/o) by low energy emulsification (LEE); the second step was to obtain stable w1/o/w2 MMEs by self-emulsifying. An extensive formulation optimization process was undertaken. The final w1/o/w2 MMEs could be formed in ddH2O, phosphate buffer solution (PBS, pH 7.4) and 1640 culture media with diameter size about 166.5 ± 13.1, 271.0 ± 11.1 and 278.7 ± 12.1 nm respectively. The release rates of siRNA from solutions, MMEs and MMEs-Gels were completed within 2 h, 6 h and13 h respectively. The transfection efficiency of MMEs was confirmed both in vitro and in vivo. The relative target gene expressions of MMEs were 0.07 ± 0.05% vs. 0.37 ± 0.06% in Hela cells against Lipofectamine2000® and 1.88% ± 0.00% vs. 9.65% ± 0.02% in mouse vaginal mucosa against PEI. Good biocompatibility of MMEs was verified by cytotoxicity and pathological studies. Overall, our results indicated the potential of the MMEs-Gel system for the vaginal delivery of siRNA.
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neat1 modulates herpes simplex virus 1 replication by regulating viral gene transcription
Cellular and Molecular Life Sciences, 2017Co-Authors: Ziqiang Wang, Yiwan Zhao, Shikuan Zhang, Jinhua Lu, Yuyang Jiang, Naihan Xu, Yaou ZhangAbstract:Nuclear paraspeckle assembly transcript 1 (NEAT1) is the crucial structural platform of paraspeckles, which is one type of nuclear bodies. As a stress-induced lncRNA, the expression of NEAT1 increases in response to viral infection, but little is known about the role of NEAT1 or paraspeckles in the replication of herpes simplex virus-1 (HSV-1). Here, we demonstrate that HSV-1 infection increases NEAT1 expression and paraspeckle formation in a STAT3-dependent manner. NEAT1 and other paraspeckle protein components, P54nrb and PSPC1, can associate with HSV-1 genomic DNA. By binding with STAT3, PSPC1 is required for the recruitment of STAT3 to paraspeckles and facilitates the interaction between STAT3 and viral gene promoters, finally increasing viral gene expression and viral replication. Furthermore, Thermosensitive Gel containing NEAT1 siRNA or STAT3 siRNA effectively healed the skin lesions caused by HSV-1 infection in mice. Our results provide insight into the roles of lncRNAs in the epigenetic control of viral genes and into the function of paraspeckles.
Ashim K Mitra - One of the best experts on this subject based on the ideXlab platform.
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Nanoparticles in Thermosensitive Gel based composite nanosystem for ocular diseases
Drug Delivery and Translational Research, 2018Co-Authors: Vibhuti Agrahari, Nikhil Dhall, Zach Aulgur, Siddhant Thukral, Ryan Conley, Sulabh P. Patel, Xiaoyan Yang, Ashim K MitraAbstract:The pentablock (PB) copolymers based composite nanosystems were designed to provide a long-term delivery of macromolecules to the back of the eye. A unique arrangement of each block (polyethylene glycol, polylactic acid, and polycaprolactone) with various molecular weights (PB-A and PB-B) was selected for the synthesis of nanoparticles (NPs) and Thermosensitive Gel (PB-C) by sequential ring-opening bulk copolymerization reaction. PB copolymers were characterized for their molecular weight and purity by 1H–NMR spectroscopy and crystallinity by PXRD. The macromolecule model drugs [lysozyme (Lyz ~ 14.5 kDa), IgG-Fab (~ 50 kDa), and IgG (~ 150 kDa)] were selected to delineate the effect of molecular weights on in vitro release profile of nanoformulations. Lyz-, Fab-, and IgG-encapsulated NPs were prepared by double emulsion solvent evaporation method. The entrapment efficiency (EE%) and drug loading (DL%) of macromolecules was higher for PB-B copolymers due to its higher molecular weight and hydrophobicity compare to PB-A. The particle size range of NPs was ~ 200–270 nm. In vitro release profiles of Lyz-, Fab-, and IgG-encapsulated in NPs alone and NPs suspended in Gel (composite nanosystem) demonstrated a minimal burst release and drug release over a long period. The effect of hydrodynamic diameter of macromolecules and hydrophobicity of PB copolymers was investigated on the release profile of nanosystems. In vitro biocompatibility study showed negligible cytokine (IL-1, IL-6, and TNF-α) release, which confirmed the safety of the PB copolymers. Based on the results, it is anticipated that long-term ocular delivery of macromolecules can be achieved through composite nanosystems.
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Nanoparticles in Thermosensitive Gel based composite nanosystem for ocular diseases
Drug Delivery and Translational Research, 2018Co-Authors: Vibhuti Agrahari, Nikhil Dhall, Zach Aulgur, Siddhant Thukral, Ryan Conley, Sulabh P. Patel, Xiaoyan Yang, Ashim K MitraAbstract:The pentablock (PB) copolymers based composite nanosystems were designed to provide a long-term delivery of macromolecules to the back of the eye. A unique arrangement of each block (polyethylene glycol, polylactic acid, and polycaprolactone) with various molecular weights (PB-A and PB-B) was selected for the synthesis of nanoparticles (NPs) and Thermosensitive Gel (PB-C) by sequential ring-opening bulk copolymerization reaction. PB copolymers were characterized for their molecular weight and purity by 1H–NMR spectroscopy and crystallinity by PXRD. The macromolecule model drugs [lysozyme (Lyz ~ 14.5 kDa), IgG-Fab (~ 50 kDa), and IgG (~ 150 kDa)] were selected to delineate the effect of molecular weights on in vitro release profile of nanoformulations. Lyz-, Fab-, and IgG-encapsulated NPs were prepared by double emulsion solvent evaporation method. The entrapment efficiency (EE%) and drug loading (DL%) of macromolecules was higher for PB-B copolymers due to its higher molecular weight and hydrophobicity compare to PB-A. The particle size range of NPs was ~ 200–270 nm. In vitro release profiles of Lyz-, Fab-, and IgG-encapsulated in NPs alone and NPs suspended in Gel (composite nanosystem) demonstrated a minimal burst release and drug release over a long period. The effect of hydrodynamic diameter of macromolecules and hydrophobicity of PB copolymers was investigated on the release profile of nanosystems. In vitro biocompatibility study showed negligible cytokine (IL-1, IL-6, and TNF-α) release, which confirmed the safety of the PB copolymers. Based on the results, it is anticipated that long-term ocular delivery of macromolecules can be achieved through composite nanosystems.
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tailor made pentablock copolymer based formulation for sustained ocular delivery of protein therapeutics
Journal of drug delivery, 2014Co-Authors: Sulabh Patel, Ravi Vaishya, Gyan P Mishra, Viral Tamboli, Dhananjay Pal, Ashim K MitraAbstract:The objective of this research article is to report the synthesis and evaluation of novel pentablock copolymers for controlled delivery of macromolecules in the treatment of posterior segment diseases. Novel biodegradable PB copolymers were synthesized by sequential ring-opening polymerization. Various ratios and molecular weights of each block (polyglycolic acid, polyethylene glycol, polylactic acid, and polycaprolactone) were selected for synthesis and to optimize release profile of FITC-BSA, IgG, and bevacizumab from nanoparticles (NPs) and Thermosensitive Gel. NPs were characterized for particle size, polydispersity, entrapment efficiency, and drug loading. In vitro release study of proteins from NPs alone and composite formulation (NPs suspended in Thermosensitive Gel) was performed. Composite formulations demonstrated no or negligible burst release with continuous near zero-order release in contrast to NPs alone. Hydrodynamic diameter of protein therapeutics and hydrophobicity of PB copolymer exhibited significant effect on entrapment efficiency and in vitro release profile. CD spectroscopy confirmed retention of structural conformation of released protein. Biological activity of released bevacizumab was confirmed by in vitro cell proliferation and cell migration assays. It can be concluded that novel PB polymers can serve a platform for sustained delivery of therapeutic proteins.
Ayman Salama - One of the best experts on this subject based on the ideXlab platform.
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soy isoflavone loaded alginate microspheres in Thermosensitive Gel base attempts to improve wound healing efficacy
Journal of Pharmacy and Pharmacology, 2019Co-Authors: Mohammed Elmowafy, Khaled Shalaby, Ayman Salama, Ghareb M. Soliman, Nabil K. Alruwaili, Ehab M Mostafa, Elshaer F Mohammed, Abd El Ghany A. Moustafa, Ameeduzzafar ZafarAbstract:Objectives This study aims to develop Thermosensitive Gel containing soy isoflavone (antioxidant and anti-inflammatory natural agent) alginate microspheres for enhancement of wound-healing performance. Methods Soy isoflavone microspheres were prepared by ionic cross-linking method and optimized using the Box-Behnken optimization design. Formulations were characterized in terms of particle size, encapsulation efficiency and equilibrium swelling degree. The optimized formula was incorporated in Pluronic F127 Gel base and examined for in vivo wound-healing efficacy. Key findings Results showed mean particle size between 18 and 25 μm, encapsulation efficiency of over 75% and equilibrium swelling degree over 1.9. Thermal analysis indicated interaction between alginate and CaCl2 and embedding of soy isoflavone in microspheres. In vivo wound-healing efficacy showed significant advance in re-epithelization, mature collagen synthesis and proangiogenesis. Immunohistochemical investigation exhibited promising alpha-smooth muscle actin immunopositive cells expression, fibroblast activation and expression of proliferating cell nuclear antigen (proliferation marker) in the epidermis and in the dermis. Conclusions The developed formulation would appear to be a promising topical preparation for accelerating healing process.
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Soy isoflavone‐loaded alginate microspheres in Thermosensitive Gel base: attempts to improve wound‐healing efficacy
The Journal of pharmacy and pharmacology, 2019Co-Authors: Mohammed Elmowafy, Khaled Shalaby, Ayman Salama, Ghareb M. Soliman, Nabil K. Alruwaili, Ehab M Mostafa, Elshaer F Mohammed, Abd El Ghany A. Moustafa, Ameeduzzafar ZafarAbstract:Objectives This study aims to develop Thermosensitive Gel containing soy isoflavone (antioxidant and anti-inflammatory natural agent) alginate microspheres for enhancement of wound-healing performance. Methods Soy isoflavone microspheres were prepared by ionic cross-linking method and optimized using the Box-Behnken optimization design. Formulations were characterized in terms of particle size, encapsulation efficiency and equilibrium swelling degree. The optimized formula was incorporated in Pluronic F127 Gel base and examined for in vivo wound-healing efficacy. Key findings Results showed mean particle size between 18 and 25 μm, encapsulation efficiency of over 75% and equilibrium swelling degree over 1.9. Thermal analysis indicated interaction between alginate and CaCl2 and embedding of soy isoflavone in microspheres. In vivo wound-healing efficacy showed significant advance in re-epithelization, mature collagen synthesis and proangiogenesis. Immunohistochemical investigation exhibited promising alpha-smooth muscle actin immunopositive cells expression, fibroblast activation and expression of proliferating cell nuclear antigen (proliferation marker) in the epidermis and in the dermis. Conclusions The developed formulation would appear to be a promising topical preparation for accelerating healing process.