cellulosic polymer
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Author(s):  
Kumar Guarve ◽  
Priyanka Kriplani

: At the present time, designing of defined release dosage forms, either controlled, sustained, modified, are gaining much importance. For the development of such delivery systems, proper blend of polymers is required, so that drug release occurs by polymer erosion, swelling, diffusion/dissolution. HPMC (hydroxypropyl methyl cellulose) is the most commonly used cellulosic polymer available in various grades to develop such types of systems. Depending upon the molecular weight and viscosity chosen, it can be applied for emulsification, adhesion, bonding, thickening, suspension, film forming and gelation. It consists of polymeric units linked together, which retain water, thereby acting as an excellent hydrophilic gel-forming polymer. It generally hydrates on the outer surface to form a gelatinous layer. It swells, expands upon contact with water and releases the drug in a predetermined manner initially and then forms a viscous gel to control the release further. The objective of the present review is to overview the recent patents and articles of HPMC, its properties, grades and its use in various drug delivery systems and as a binder, dispersing agent, bioavailability enhancer and as capsule forming material have been identified and reviewed.


Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 256
Author(s):  
Aurelia Cristina Nechifor ◽  
Simona Cotorcea ◽  
Constantin Bungău ◽  
Paul Constantin Albu ◽  
Dumitru Pașcu ◽  
...  

The unpleasant odor that appears in the industrial and adjacent waste processing areas is a permanent concern for the protection of the environment and, especially, for the quality of life. Among the many variants for removing substance traces, which give an unpleasant smell to the air, membrane-based methods or techniques are viable options. Their advantages consist of installation simplicity and scaling possibility, selectivity; moreover, the flows of odorous substances are direct, automation is complete by accessible operating parameters (pH, temperature, ionic strength), and the operation costs are low. The paper presents the process of obtaining membranes from cellulosic derivatives containing silver nanoparticles, using accessible raw materials (namely motion picture films from abandoned archives). The technique used for membrane preparation was the immersion precipitation for phase inversion of cellulosic polymer solutions in methylene chloride: methanol, 2:1 volume. The membranes obtained were morphologically and structurally characterized by scanning electron microscopy (SEM) and high resolution SEM (HR SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectrometry (FTIR), thermal analysis (TG, ATD). Then, the membrane performance process (extraction efficiency and species flux) was determined using hydrogen sulfide (H2S) and ethanethiol (C2H5SH) as target substances.


2020 ◽  
Vol 202 (13) ◽  
Author(s):  
Wiriya Thongsomboon ◽  
Sabrina H. Werby ◽  
Lynette Cegelski

ABSTRACT Bacterial biofilms are surface-associated communities of bacterial cells enmeshed in an extracellular matrix (ECM). The biofilm lifestyle results in physiological heterogeneity across the community, promotes persistence, and protects cells from external insults such as antibiotic treatment. Escherichia coli was recently discovered to produce a chemically modified form of cellulose, phosphoethanolamine (pEtN) cellulose, which contributes to the formation of its extracellular matrix and elaboration of its hallmark wrinkled macrocolony architectures. Both pEtN cellulose and unmodified cellulose bind dyes such as calcofluor white and Congo red (CR). Here, we present the use of CR fluorescence to distinguish between pEtN cellulose and unmodified cellulose producers. We demonstrate the utility of this tool in the evaluation of a uropathogenic E. coli clinical isolate that appeared to produce curli and a cellulosic component but did not exhibit macrocolony wrinkling. We determined that lack of macrocolony wrinkling was attributed to a single-nucleotide mutation and introduction of a stop codon in bcsG, abrogating production of BcsG, the pEtN transferase. Thus, this work underscores the important contribution of the pEtN cellulose modification to the E. coli agar-based macrocolony wrinkling phenotype and introduces a facile approach to distinguish between modified and unmodified cellulose. IMPORTANCE E. coli bacteria produce amyloid fibers, termed curli, and a cellulosic component to assemble biofilm communities. Cellulose is the most abundant biopolymer on Earth, and we recently discovered that the cellulosic component in E. coli biofilms was not standard cellulose, but a newly identified cellulosic polymer, phosphoethanolamine cellulose. Studies involving the biological and functional impact of this cellulose modification among E. coli and other organisms are just beginning. Convenient methods for distinguishing pEtN cellulose from unmodified cellulose in E. coli and for estimating production are needed to facilitate further research. Dissecting the balance of pEtN cellulose and curli production by E. coli commensal strains and clinical isolates will improve our understanding of the host microbiome and of factors contributing to bacterial pathogenesis.


Pharmaceutics ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 23 ◽  
Author(s):  
Reynaldo Salas-Zúñiga ◽  
Christian Rodríguez-Ruiz ◽  
Herbert Höpfl ◽  
Hugo Morales-Rojas ◽  
Obdulia Sánchez-Guadarrama ◽  
...  

The effect of hydroxypropyl methylcellulose (HPMC) and methylcellulose (Methocel® 60 HG) on the dissolution behavior of two cocrystals derived from nitazoxanide (NTZ), viz., nitazoxanide-glutaric acid (NTZ-GLU, 1:1) and nitazoxanide-succinic acid (NTZ-SUC, 2:1), was explored. Powder dissolution experiments under non-sink conditions showed similar dissolution profiles for the cocrystals and pure NTZ. However, pre-dissolved cellulosic polymer in the phosphate dissolution medium (pH 7.5) modified the dissolution profile of NTZ when starting from the cocrystals, achieving transient drug supersaturation. Subsequent dissolution studies under sink conditions of polymer-based pharmaceutical powder formulations with NTZ-SUC cocrystals gave a significant improvement of the apparent solubility of NTZ when compared with analogous formulations of pure NTZ and the physical mixture of NTZ and SUC. Scanning electron microscopy and powder X-ray diffraction analysis of samples recovered after the powder dissolution studies showed that the cocrystals undergo fast dissolution, drug supersaturation and precipitation both in the absence and presence of polymer, suggesting that the solubilization enhancement is due to polymer-induced delay of nucleation and crystal growth of the less soluble NTZ form. The study demonstrates that the incorporation of an appropriate excipient in adequate concentration can be a key factor for inducing and maintaining the solubilization of poorly soluble drugs starting from co-crystallized solid forms. In such a way, cocrystals can be suitable for the development of solid dosage forms with improved bioavailability and efficacy in the treatment of important parasitic and viral diseases, among others.


2018 ◽  
Vol 1 (3) ◽  
pp. 593-604
Author(s):  
Fuad Hasan ◽  
Sofyan M. Saleh ◽  
Renni Anggraini

Abstract: Road construction in Indonesia in the stage of implementation has not been able to fully meet the needs of transportation, it is indicated by the presence of early failure due to an increase in vehicle load and climate change. Many attempts have been made to improve the quality of the mixture, one with a polymer modified asphalt. Cigarette filters are made of cellulose acetate thousands of polymer chains, once discharged into the environment, cigarette filter making a big issue of the environmental impact. The content in the form of cigarette filter waste cellulosic polymer asitate which has thermoplastic properties, binding with plasticizers, resistant to heat and pressure. Therefore, it is necessary to study polymer modified asphalt with subtitution filter cigarettes waste into the asphalt. In this study, cigarette filter waste is substituted into the asphalt at 2%, 3%, and 4%. The aims of this study is able to know the utilization of filter cigarettes waste as improving the quality of asphalt concrete and efficient use of asphalt and waste reduction. The Impact of using cigarette filter waste higher in AC-WC mixture tend increased the parameter Marshall, especially the value of stability and MQ. The highest  MQ and stability value obtained in AC-WC mixture with 4% subtitution  cigarette filter waste and 5.81% asphalt content, those are 3107.67 kg and 112.81 kg / mm. No big changes in the VMA and density value for all substitution percentage variation of cigarette filter waste. VFA and flow value decrease with increasing the percentage of cigarette filter waste, while the VIM value tends to increase. The durability value of AC-WC mixture with and without substitution percentage variation cigarette filter waste meets the requirements, those were 90%.Abstrak: Pembangunan jalan di Indonesia dalam tahap pelaksanaanya belum mampu sepenuhnya memenuhi kebutuhan transportasi, hal tersebut terindikasi dengan adanya kerusakan dini akibat dari peningkatan beban kendaraan dan perubahan iklim. Banyak usaha telah dilakukan untuk meningkatkan kualitas campuran, salah satunya dengan menggunakan aspal modifikasi polimer. Filter rokok terbuat dari ribuan rantai polimer selulosa asetat, setelah dibuang ke lingkungan, filter rokok membuat masalah besar akan dampak lingkungan. Kandungan di dalam limbah filter rokok tersebut berupa polimer selulosa asitate yang memiliki sifat termoplastik, berikatan dengan plasticizers, tahan terhadap panas dan tekanan. Oleh karena itu perlu dilakukan penelitian aspal modifikasi polimer dengan mensubtitusikan limbah filter rokok ke dalam aspal. Pada penelitian ini limbah filter rokok disubtitusikan ke dalam aspal sebesar 2%, 3%, dan 4%. Tujuan penelitian ini adalah dapat diketahuinya pemanfaatan limbah filter rokok sebagai upaya peningkatan mutu campuran aspal beton serta penghematan penggunaan aspal dan pengurangan limbah. Dampak penggunaan limbah filter rokok yang semakin tinggi dalam campuran AC-WC membuat peningkatkan pada nilai parameter Marshall, terutama nilai stabilitas dan MQ. Nilai stabilitas dan MQ tertinggi didapat pada campuran limbah filter rokok dengan persentase limbah filter rokok 4% dan kadar aspal 5,81% yaitu 3107,67 kg dan 112,81 kg/mm. Nilai density dan VMA tidak terjadi perubahan yang besar untuk semua substitusi variasi persentase limbah filter rokok. Nilai flow dan VFA mengalami penurunan seiring dengan peningkatan persentase limbah filter rokok, sedangkan nilai VIM cenderung meningkat. Untuk nilai durabilitas campuran AC-WC dengan dan tanpa substitusi variasi persentase limbah filter rokok telah memenuhi persyaratan yaitu 90%.


2017 ◽  
Vol 118 ◽  
pp. 31-40 ◽  
Author(s):  
Vivekananda Bal ◽  
Vikas Gayasen ◽  
Reena Bibals ◽  
Amol P. Avhad ◽  
Debojit Chakrabarty ◽  
...  

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