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Pal N, Banerjee S, Roy P, Pal K. Cellulose nanocrystals‑silver nanoparticles-reduced graphene oxide based hybrid PVA nanocomposites and its antimicrobial properties. Int J Biol Macromol 2021; 191:445-456. [PMID: 34555401 DOI: 10.1016/j.ijbiomac.2021.08.237] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 08/17/2021] [Accepted: 08/31/2021] [Indexed: 11/25/2022]
Abstract
Towards fabricating a hybrid biodegradable multifunctional nanocomposite, cellulose nanocrystal (CNC), reduced graphene oxide (rGO) and silver (Ag) nanoparticles were reinforced into polyvinyl alcohol (PVA) polymer matrix. One-step reduction process was followed, composed of reducing graphene oxide (GO) and silver nitrate (AgNO3) into rGO and Ag nanoparticles through hydrazine hydrate (chemical reduction method), respectively. Uniformly dispersed CNC, rGO and Ag nanoparticles in PVA matrix led to an increment in modulus by 184% of PVA demonstrating the reinforcement outcome of CNC, rGO and Ag. PVA/CNC/rGO/Ag nanocomposite showed the Ag+ ions sustained release from PVA studied using Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The incorporation and elemental composition of CNC, rGO and Ag nanoparticles into nanocomposite were interpreted through FTIR (Fourier Transform Infrared Spectroscopy) and XPS (X-ray photoelectron spectroscopy) technique, respectively. All prepared nanocomposites with different wt% of Ag (PVA, PVA/CNC, PVA/CNC/rGO/Ag) were non-toxic to HEK-293 cell line and exhibited improved antibacterial property against E. coli and S. aureus due to a combination of Ag+ ions (release from Ag nanoparticles) and rGO (having antibacterial effect). Thus, the combined effect of CNC, rGO and Ag in PVA matrix distinctively resulted into a multifunctional hybrid nanocomposite for potential use in tissue engineering and packaging applications.
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Affiliation(s)
- Nidhi Pal
- Department of Mechanical and Industrial Engineering, IIT Roorkee, Uttarakhand 247667, India
| | - Somesh Banerjee
- Department of Biotechnology, IIT Roorkee, Uttarakhand 247667, India
| | - Partha Roy
- Department of Biotechnology, IIT Roorkee, Uttarakhand 247667, India
| | - Kaushik Pal
- Department of Mechanical and Industrial Engineering, IIT Roorkee, Uttarakhand 247667, India; Center for Nanotechnology, IIT Roorkee, Uttarakhand 247667, India.
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Characterization and Laser Structuring of Aqueous Processed Li(Ni 0.6Mn 0.2Co 0.2)O 2 Thick-Film Cathodes for Lithium-Ion Batteries. NANOMATERIALS 2021; 11:nano11071840. [PMID: 34361226 PMCID: PMC8308203 DOI: 10.3390/nano11071840] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/06/2021] [Accepted: 07/13/2021] [Indexed: 11/26/2022]
Abstract
Lithium-ion batteries have led the revolution in portable electronic devices and electrical vehicles due to their high gravimetric energy density. In particular, layered cathode material Li(Ni0.6Mn0.2Co0.2)O2 (NMC 622) can deliver high specific capacities of about 180 mAh/g. However, traditional cathode manufacturing involves high processing costs and environmental issues due to the use of organic binder polyvinylidenfluoride (PVDF) and highly toxic solvent N-methyl-pyrrolidone (NMP). In order to overcome these drawbacks, aqueous processing of thick-film NMC 622 cathodes was studied using carboxymethyl cellulose and fluorine acrylic hybrid latex as binders. Acetic acid was added during the mixing process to obtain slurries with pH values varying from 7.4 to 12.1. The electrode films could be produced with high homogeneity using slurries with pH values smaller than 10. Cyclic voltammetry measurements showed that the addition of acetic acid did not affect the redox reaction of active material during charging and discharging. Rate capability tests revealed that the specific capacities with higher slurry pH values were increased at C-rates above C/5. Cells with laser structured thick-film electrodes showed an increase in capacity by 40 mAh/g in comparison to cells with unstructured electrodes.
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Percutaneous delivery of levetiracetam as an alternative to topical nonsteroidal anti-inflammatory drugs: formulation development, in vitro and in vivo characterization. Drug Deliv Transl Res 2020; 11:227-241. [PMID: 32451940 DOI: 10.1007/s13346-020-00787-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The study focused on formulation of carmellose sodium hydrogels and nonionic microemulsions with 5% and 10% of levetiracetam and investigation of drug concentration influence on their physicochemical characteristics and in-use stability as well as influence of drug concentration and carrier type on in vitro drug release and in vivo antihyperalgesic/antiedematous activity in a rat model of localized (intraplantar) carrageenan-induced inflammation. Hydrogels were pseudoplastic semisolids with thixotropy and pH 7.37-7.58. Microemulsions were low viscous Newtonian nanodispersions of oil droplets (13.11-15.11 nm) in water, with pH 4.01-4.64. Physical stability of the investigated systems was preserved over the 3-month storage under ambient conditions. Levetiracetam release followed zero order and Korsmeyer-Peppas models (R2 ≥ 0.99) reflecting the combined effects of drug concentration and carrier viscosity. All levetiracetam-loaded formulations produced significant reduction of hyperalgesia and paw swelling induced by carrageenan (p < 0.001). Their efficacy in exerting antihyperalgesic activity was significantly higher than that observed with the reference 5% ibuprofen hydrogel preparation (up to 6 h) (p < 0.001), while antiedematous activity was comparable with the reference product. No erythema and visible blood vessels were observed in a rat ear test. The study demonstrated percutaneous delivery of levetiracetam as useful and safe therapeutic option for localized inflammatory pain with potential to overcome the insufficient efficacy of topically applied nonsteroidal anti-inflammatory drugs in the form of a hydrogel. Graphical abstract.
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Sun J, Zuo XB, Fang S, Xu HN, Chen J, Meng YC, Chen T. Effects of cellulose derivative hydrocolloids on pasting, viscoelastic, and morphological characteristics of rice starch gel. J Texture Stud 2016; 48:241-248. [DOI: 10.1111/jtxs.12233] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/03/2016] [Accepted: 10/07/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Jing Sun
- School of Food Science and Biotechnology; Zhejiang Gongshang University; Xuezheng Street No. 18 Hangzhou 310018 China
| | - Xiao-Bo Zuo
- School of Food Science and Biotechnology; Zhejiang Gongshang University; Xuezheng Street No. 18 Hangzhou 310018 China
| | - Sheng Fang
- School of Food Science and Biotechnology; Zhejiang Gongshang University; Xuezheng Street No. 18 Hangzhou 310018 China
| | - Hua-Neng Xu
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology; Jiangnan University; 1800 Lihu Avenue Wuxi Jiangsu 214122 China
| | - Jie Chen
- School of Food Science and Biotechnology; Zhejiang Gongshang University; Xuezheng Street No. 18 Hangzhou 310018 China
| | - Yue-Cheng Meng
- School of Food Science and Biotechnology; Zhejiang Gongshang University; Xuezheng Street No. 18 Hangzhou 310018 China
| | - Tao Chen
- School of Food Science and Biotechnology; Zhejiang Gongshang University; Xuezheng Street No. 18 Hangzhou 310018 China
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Shi Y, Xiong D, Liu Y, Wang N, Zhao X. Swelling, mechanical and friction properties of PVA/PVP hydrogels after swelling in osmotic pressure solution. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 65:172-80. [DOI: 10.1016/j.msec.2016.04.042] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 03/18/2016] [Accepted: 04/11/2016] [Indexed: 11/28/2022]
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6
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Statistical modelling of the rheological and mucoadhesive properties of aqueous poly(methylvinylether-co-maleic acid) networks: Redefining biomedical applications and the relationship between viscoelasticity and mucoadhesion. Colloids Surf B Biointerfaces 2016; 144:125-134. [DOI: 10.1016/j.colsurfb.2016.03.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/29/2016] [Accepted: 03/02/2016] [Indexed: 11/30/2022]
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Zhang C, Zhu Y, Zhang R, Xie Y, Wang K, Liu X. Pickering emulsions stabilized by composite nanoparticles prepared from lysozyme and dopamine modified poly (γ-glutamic acid): effects of pH value on the stability of the emulsion and the activity of lysozyme. RSC Adv 2015. [DOI: 10.1039/c5ra10737g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Novel composite nanoparticles were prepared from lysozyme and modified poly (γ-glutamic acid) to be used as emulsifiers for Pickering emulsions. Increasing the pH value of the solution facilitated the formation of gel-like emulsions suitable for releasing lysozyme.
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Affiliation(s)
- Cuige Zhang
- Key Laboratory of Food Colloids and Biotechnology
- Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122
| | - Ye Zhu
- Key Laboratory of Food Colloids and Biotechnology
- Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122
| | - Rongli Zhang
- Key Laboratory of Food Colloids and Biotechnology
- Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122
| | - Yanling Xie
- Key Laboratory of Food Colloids and Biotechnology
- Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122
| | - Kangjing Wang
- Key Laboratory of Food Colloids and Biotechnology
- Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122
| | - Xiaoya Liu
- Key Laboratory of Food Colloids and Biotechnology
- Ministry of Education
- School of Chemical and Material Engineering
- Jiangnan University
- Wuxi 214122
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Wang J, Zhang H, An D, Yu J, Li W, Shen T, Wang J. Rheological characterization of cataplasm bases composed of cross-linked partially neutralized polyacrylate hydrogel. AAPS PharmSciTech 2014; 15:1149-54. [PMID: 24865937 DOI: 10.1208/s12249-014-0148-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 05/07/2014] [Indexed: 11/30/2022] Open
Abstract
Viscoelasticity is a useful parameter for characterizing the intrinsic properties of the cross-linked polyacrylate hydrogel used in cataplasm bases. The aim of this study was to investigate the effects of various formulation parameters on the rheological characteristics of polyacrylate hydrogel. The hydrogel layers were formed using a partially neutralized polyacrylate (Viscomate(™)), which contained acrylic acid and sodium acrylate in different copolymerization ratios, as the cross-linked gel framework. Dihydroxyaluminum aminoacetate (DAAA), which produces aluminum ions, was used as the cross-linking agent. Rheological analyses were performed using a "stress amplitude sweep" and a "frequency sweep". The results showed that greater amounts of acrylic acid in the structure of Viscomate as well as higher concentrations of DAAA and Viscomate led to an increase in the elastic modulus (G'). However, greater amounts of acrylic acid in the structure of Viscomate and higher concentrations of DAAA had an opposite on the viscous modulus (G″); this might be owing to higher steric hindrance. The results of this study can serve as guidelines for the optimization of formulations for cataplasms.
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Vogl US, Das PK, Weber AZ, Winter M, Kostecki R, Lux SF. Mechanism of interactions between CMC binder and Si single crystal facets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:10299-10307. [PMID: 25109709 DOI: 10.1021/la501791q] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Interactions of the active material particles with the binder are crucial in tailoring the properties of composite electrodes used in lithium-ion batteries. The dependency of the protonation degree of the carboxyl group in the carboxymethyl cellulose (CMC) structure on the pH value of the preparation solution was investigated by Fourier transform infrared spectroscopy (FTIR). Three different distinctive chemical states of CMC binder were chosen (protonated, deprotonated, and half-half), and their interactions with different silicon single crystal facets were investigated. The different Si surface orientations display distinct differences of strength of interactions with the CMC binder. The CMC/Si adhesion forces in solution and Si wettability of the silicon are also strongly dependent on the protonation degree of the CMC. This work provides an insight into the nature of these interactions, which determine the electrochemical performance of silicon composite electrodes.
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Affiliation(s)
- U S Vogl
- MEET Battery Research Center, Westfälische Wilhelms-Universität Münster , Corrensstraße 46, 48149 Münster, Germany
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Das S, Ng WK, Tan RBH. Sucrose ester stabilized solid lipid nanoparticles and nanostructured lipid carriers. II. Evaluation of the imidazole antifungal drug-loaded nanoparticle dispersions and their gel formulations. NANOTECHNOLOGY 2014; 25:105102. [PMID: 24531828 DOI: 10.1088/0957-4484/25/10/105102] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This study focused on: (i) feasibility of the previously developed sucrose ester stabilized SLNs and NLCs to encapsulate different imidazole antifungal drugs and (ii) preparation and evaluation of topical gel formulations of those SLNs and NLCs. Three imidazole antifungal drugs; clotrimazole, ketoconazole and climbazole were selected for this study. The results suggested that size, size distribution and drug encapsulation efficiency depend on the drug molecule and type of nanoparticles (SLN/NLC). The drug release experiment always showed faster drug release from NLCs than SLNs when the same drug molecule was loaded in both nanoparticles. However, drug release rate from both SLNs and NLCs followed the order of climbazole > ketoconazole > clotrimazole. NLCs demonstrated better physicochemical stability than SLNs in the case of all drugs. The drug release rate from ketoconazole- and clotrimazole-loaded SLNs became faster after three months than a fresh formulation. There was no significant change in drug release rate from climbazole-loaded SLNs and all drug-loaded NLCs. Gel formulations of SLNs and NLCs were prepared using polycarbophil polymer. Continuous flow measurements demonstrated non-Newtonian flow with shear-thinning behavior and thixotropy. Oscillation measurements depicted viscoelasticity of the gel formulations. Similar to nanoparticle dispersion, drug release rate from SLN- and NLC-gel was in the order of climbazole > ketoconazole > clotrimazole. However, significantly slower drug release was noticed from all gel formulations than their nanoparticle counterparts. Unlike nanoparticle dispersions, no significant difference in drug release from gel formulations containing SLNs and NLCs was observed for each drug. This study concludes that gel formulation of imidazole drug-loaded SLNs and NLCs can be used for sustained/prolonged topical delivery of the drugs.
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Affiliation(s)
- Surajit Das
- Institute of Chemical and Engineering Sciences, A*STAR (Agency for Science, Technology and Research), 1 Pesek Road, Jurong Island, Singapore 627833, Singapore
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11
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A Hybrid Methacrylate-Sodium Carboxymethylcellulose Interpolyelectrolyte Complex: Rheometry and in Silico Disposition for Controlled Drug Release. MATERIALS 2013; 6:4284-4308. [PMID: 28788332 PMCID: PMC5452861 DOI: 10.3390/ma6104284] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 08/13/2013] [Accepted: 08/16/2013] [Indexed: 11/23/2022]
Abstract
The rheological behavioral changes that occurred during the synthesis of an interpolyelectrolyte complex (IPEC) of methacrylate copolymer and sodium carboxymethylcellulose were assessed. These changes were compared with the rheological behavior of the individual polymers employing basic viscosity, yield stress, stress sweep, frequency sweep, temperature ramp as well as creep and recovery testing. The rheological studies demonstrated that the end-product of the complexation of low viscous methacrylate copolymer and entangled solution of sodium carboxymethylcellulose generated a polymer, which exhibited a solid-like behavior with a three-dimensional network. Additionally, the rheological profile of the sodium carboxymethylcellulose and methacrylate copolymer with respect to the effect of various concentrations of acetic acid on the synthesis of the IPEC was elucidated using molecular mechanics energy relationships (MMER) by exploring the spatial disposition of carboxymethylcellulose and methacrylate copolymer with respect to each other and acetic acid. The computational results corroborated well with the experimental in vitro drug release data. Results have shown that the IPEC may be suitable polymeric material for achieving controlled zero-order drug delivery.
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13
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Maderuelo C, Zarzuelo A, Lanao JM. Critical factors in the release of drugs from sustained release hydrophilic matrices. J Control Release 2011; 154:2-19. [DOI: 10.1016/j.jconrel.2011.04.002] [Citation(s) in RCA: 337] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 03/29/2011] [Indexed: 11/30/2022]
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14
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Seetapan N, Bejrapha P, Srinuanchai W, Puttipipatkhachorn S, Ruktanonchai U. Nondestructive rheological measurement of aqueous dispersions of solid lipid nanoparticles: effects of lipid types and concentrations on dispersion consistency. Drug Dev Ind Pharm 2010; 36:1005-15. [DOI: 10.3109/03639040903586273] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Nispa Seetapan
- National Metal and Materials Technology Center, National Science and Technology Development Agency, Pathumthani, Thailand
| | - Piyawan Bejrapha
- National Nanotechnology Center, National Science and Technology Development Agency, Pathumthani, Thailand
| | - Wanwisa Srinuanchai
- National Nanotechnology Center, National Science and Technology Development Agency, Pathumthani, Thailand
| | - Satit Puttipipatkhachorn
- Department of Manufacturing Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Uracha Ruktanonchai
- National Nanotechnology Center, National Science and Technology Development Agency, Pathumthani, Thailand
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Bhattarai S, Bunt C, Rathbone M, Alany RG. Phase behavior, rheological and mechanical properties of hydrophilic polymer dispersions. Pharm Dev Technol 2010; 16:259-68. [PMID: 20230192 DOI: 10.3109/10837451003664073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Liquid polymeric systems that can undergo phase change (sol to gel) upon administration into the teat canal of cow's mammary gland can serve as a physical barrier to invading pathogens and can also serve as a reservoir for controlled release of therapeutic agents. The aim of the study was to investigate the phase behavior, rheological and mechanical properties of selected in situ gelling systems. Six in situ gelling polymer formulations were identified using phase behavior studies. Rheological studies revealed pseudoplastic flow with thixotropy. All six formulations showed significantly different viscosity, pseudoplasticity and thixotropy values except for CMC1 and HPMC2 which where statistically similar. The gel strength was dependent on the solvent system used and amount of water in the system. These in situ gelling systems have the potential to serve as a platform for development of intramammary formulations intended for administration into the teat canal of the cow's mammary gland. They can serve as a physical barrier or a matrix for controlled drug release.
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Affiliation(s)
- Sushila Bhattarai
- Drug Delivery Research Unit (DDRU), School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand
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16
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Zhang C, Easteal AJ. Encapsulation of diclofenac sodium with acidic copolymer hydrogels based on PEG/poly( N-isopropylacrylamide- co-2-acrylamido-2-methyl-1-propanesulfonic acid) semi-interpenetrating network using in situloading technique. J Appl Polym Sci 2009. [DOI: 10.1002/app.30021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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17
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Yoon HS, Lim ST. Utilization of Enzyme-resistant Starch to Control Theophylline Release from Tablets. STARCH-STARKE 2009. [DOI: 10.1002/star.200800057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kittipongpatana OS, Burapadaja S, Kittipongpatana N. Carboxymethyl mungbean starch as a new pharmaceutical gelling agent for topical preparation. Drug Dev Ind Pharm 2009; 35:34-42. [PMID: 18720150 DOI: 10.1080/03639040802144229] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
An application of carboxymethyl mungbean starch (CMMS) as a gelling agent in the topical pharmaceutical preparation was investigated. CMMS was prepared using specific conditions that yielded a high-viscosity product. Polymer gels and gel bases were prepared at 1-10% (wt/wt), and physicochemical studies were carried out in comparison with four standard gelling agents: carbopol 940 (CP), hydroxypropylmethyl cellulose (HPMC), methyl cellulose (MC), and sodium carboxymethyl cellulose (SCMC). Piroxicam was used as a model drug to study the drug release profile of the gel formulations. The tackless, greaseless, and transparent CMMS gels exhibited pseudoplastic behavior with thixotropy at concentrations less than 5% (wt/wt). At a concentration of 5% (wt/wt) and higher, the semisolid gels showed plastic flow characteristics. Viscosity and X-ray diffraction results indicated a good compatibility between CMMS and the acidic piroxicam. No precipitation of piroxicam or phase separation was observed during a stability test. The release rate of piroxicam from 3% (wt/wt) CMMS gel was 1,003.79 +/- 105.08 microg/cm(2), which was comparable with 947.66 +/- 133.70 microg/cm(2) obtained from a 0.5% (wt/wt) carbopol formulation. The release profiles of both formulations were consistent and remained unchanged after 2 months' storage. Viscosity played an important role in controlling the release rate of low concentration CMMS formulations by regulating the drug diffusion. At a concentration of 5% (wt/wt) CMMS and higher, the release rates of piroxicam were not significantly different. A plausible explanation based on the nature of the gelling agent was proposed. Stability and drug release profiles of CMMS and commercial gelling agents were compared. The results supported the potential use of CMMS as a new, effective gelling agent for topical gel preparation.
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Affiliation(s)
- Ornanong S Kittipongpatana
- Department of Pharmaceutical Sciences, Department of Pharmaceutical Care, Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand
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Zhang C, Easteal AJ. Rheological properties of poly(ethylene glycol)/poly(N‐isopropylacrylamide‐co‐2‐acrylamido‐2‐methylpropanesulphonic acid) semi‐interpenetrating networks. J Appl Polym Sci 2008. [DOI: 10.1002/app.28481] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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Pan Y, Xiong D, Gao F. Viscoelastic behavior of nano-hydroxyapatite reinforced poly(vinyl alcohol) gel biocomposites as an articular cartilage. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:1963-1969. [PMID: 17943417 DOI: 10.1007/s10856-007-3280-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Accepted: 09/18/2007] [Indexed: 05/25/2023]
Abstract
Nanohydroxyapatite reinforced poly(vinyl alcohol) gel (nano-HA/PVA gel) composites has been proposed as an articular cartilage repair biomaterial. In this paper, nano-HA/PVA gel composites were prepared by in situ synthesis nano-HA particles in PVA solution and accompanied with freeze/thaw method. The influence of nano-HA content, PVA concentration, test frequency and freeze/thaw cycle times on the viscoelastic behavior of nano-HA/PVA gel composites were evaluated using dynamic mechanical thermal analysis (DMTA). The results showed that both storage modulus and loss modulus firstly increased and then presented decreasing trend with the rise of nano-HA content. Their maximum values were obtained while nano-HA content was 6%. Furthermore, the G' and G'' of the composites improve with the increase of PVA concentrations and freeze/thaw cycle times. This effect was more distinct at low freeze/thaw cycles. The phase angle (tan delta) of the pure PVA gel is larger than that of the nano-HA/PVA composites at the test frequency spectra, but all the phase angle values of the tested composites were close to that of nature bone.
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Affiliation(s)
- Yusong Pan
- Department of Material Science & Engineering, Nan Jing University of Science and Technology, Nan Jing, 21009, P.R. China.
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21
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Ueno T, Yokota S, Kitaoka T, Wariishi H. Conformational changes in single carboxymethylcellulose chains on a highly oriented pyrolytic graphite surface under different salt conditions. Carbohydr Res 2007; 342:954-60. [PMID: 17316582 DOI: 10.1016/j.carres.2007.01.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2006] [Revised: 01/22/2007] [Accepted: 01/25/2007] [Indexed: 11/21/2022]
Abstract
Conformational changes in individual carboxymethylcellulose (CMC) chains deposited on a highly oriented pyrolytic graphite (HOPG) surface were investigated by atomic force microscopy (AFM). A small amount of CMC solution with various salt concentrations was deposited onto the HOPG surface. The CMC molecular chains adsorbed onto the HOPG surface were clearly visualized using tapping-mode AFM under ambient conditions, as compared with those on a hydrophilic mica surface. Each CMC chain was distinguishable at the molecular level based on the vertical profiles of the AFM images, and probably aligned along the HOPG crystal lattice. Higher NaCl concentrations brought about dramatic conformational changes from aligned single chains to globular aggregates via the molecular network structure only on the HOPG surface through electrostatic screening of the CM groups. Although CMC is a water-soluble hydrophilic polyelectrolyte, some interaction, possibly due to a CH-pi bonding between the glucopyranosic axial plane of CMC and the aromatic rings of HOPG, is considered to be effective and dominant for the unique molecular attachment. These phenomena would imply the potential use of HOPG as a substrate for not only molecular imaging, but also for nano-scale morphological control of cellulosic polymers and other structural polysaccharides.
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Affiliation(s)
- Tomotsugu Ueno
- Department of Forest and Forest Products Sciences, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan
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Lippacher A, Müller RH, Mäder K. Liquid and semisolid SLN dispersions for topical application: rheological characterization. Eur J Pharm Biopharm 2005; 58:561-7. [PMID: 15451530 DOI: 10.1016/j.ejpb.2004.04.009] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Revised: 02/20/2004] [Accepted: 04/20/2004] [Indexed: 11/28/2022]
Abstract
Aqueous dispersions of solid lipid nanoparticles (SLN) are promising drug carrier systems for topical application. A drawback, however, is the need of incorporating the SLN dispersion in commonly used dermal carriers (creams, gels) to obtain the required semisolid consistency for dermal application. This study describes the production of SLN dispersions having the desired semisolid consistency by a one-step process. Physical characterization of these systems in terms of particle size and rheological properties revealed some interesting features. Despite the high lipid content it was possible to produce colloidal dispersions by high pressure homogenization. Continuous flow measurements revealed systems with yield point, plastic flow and thixotropy. Oscillation measurements proved the viscoelastic microstructure of the SLN dispersions. Higher concentrated SLN dispersions were found to have a prevailing elastic component in contrast to lower concentrated systems. Viscoelastic properties of a 40% SLN dispersion were found to be comparable to standard dermal preparations. Storage stability at room temperature in terms of particle size could be demonstrated over a 6-month period. The development of the gel structure of semisolid SLN dispersions is delayed comparable to commercial O/W creams with non-ionic emulsifiers. Parameters like concentration of the dispersed phase, particle size and particle shape were identified as significant factors influencing the microstructure of these complex semisolid systems.
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Affiliation(s)
- A Lippacher
- Department of Pharmaceutics, Biopharmaceutics and Biotechnology, Free University of Berlin, Berlin, Germany
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Michailova V, Titeva S, Kotsilkova R, Krusteva E, Minkov E. Influence of hydrogel structure on the processes of water penetration and drug release from mixed hydroxypropylmethyl cellulose/thermally pregelatinized waxy maize starch hydrophilic matrices. Int J Pharm 2001; 222:7-17. [PMID: 11404028 DOI: 10.1016/s0378-5173(01)00706-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The kinetics of water penetration and molsidomine release from both hydroxypropylmethyl cellulose (HPMC) and mixed HPMC/thermally pregelatinized waxy maize starch (SDWMT) hydrophilic matrices has been examined in 0.1 mol x dm(-3) HCl (pH 1.0) and 0.06 mol x dm(-3) Na3PO4/HCl buffer (pH 6.8). The rheological oscillatory test parameters of their gel layers obtained by swelling of the matrices in the two aqueous media have been observed. The kinetic swelling properties of mixed HPMC/SDWMT hydrogels (i.e. degree and velocity of both water penetration and swelling, transport mechanism which controls solvent sorption) directly influence the drug release behaviour and the structural features of the formed gel layer. Both diffusion processes are diffusion-controlled ones, their mechanisms being influenced insignificantly by the relaxation properties of the hydrated macromolecules. It has been established by means of comparative viscoelastic analysis, that mixed HPMC/SDWMT hydrogels demonstrate the typical behaviour of 'filled' composite systems having poor adhesion between the surface of the elastic SDWMT 'filler' and the continuous HPMC phase. Due to the inter-phase relations between the swollen starch granules and the linear cellulose derivative as well as to the specific structure of amylopectin molecule, the pregelatinized waxy maize starch shows a stronger influence on the velocities of both water penetration and drug release from mixed HPMC/SDWMT matrices.
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Affiliation(s)
- V Michailova
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Medical University, 2 Dunav Street, 1000, Sofia, Bulgaria.
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Lippacher A, Müller RH, Mäder K. Investigation on the viscoelastic properties of lipid based colloidal drug carriers. Int J Pharm 2000; 196:227-30. [PMID: 10699724 DOI: 10.1016/s0378-5173(99)00428-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The rheological behaviour of solid lipid nanoparticle dispersions (SLN) prepared by high pressure homogenization was investigated using a Haake RS-100 rheometer. Four preparations differing in their lipid content and macroscopic consistency were tested by continuous shear rheometry and oscillatory testing. Rheological data from continuous shear measurement reveal plastic flow for systems with low lipid content as well as for systems with high lipid content. By using oscillatory testing more detailed information concerning the structure could be achieved. Rheological measurements of 40% lipid dispersions show viscoelastic properties comparable to the data from standard dermal preparations. Therefore high concentrated lipid dispersions might constitute a promising vehicle for topical administration.
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Affiliation(s)
- A Lippacher
- Department of Pharmaceutics, Biopharmaceutics and Biotechnology, Free University of Berlin, Kelchstr. 31, D-12169, Berlin, Germany
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