Cellulose
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Methods in enzymology ; Vol. 160
774 s. : il.
Při magistraliter přípravě slizů a gelů se v praxi nejčastěji používají deriváty celulosy, želatina a karbomery. Tento článek je věnován derivátům celulosy. Jsou uvedeny lékopisné a nejznámější obchodní názvy, základní fyzikálně-chemické vlastnosti, hodnoty viskozity 2% vodných disperzí, dispergační techniky a uvedeny příklady chybných receptur dosud se vyskytujících v praxi. Deriváty celulosy by měly být označeny lékopisným, nikoli obchodním názvem a do lékárny dodány s deklarovanou hodnotou viskozity a dalšími vlastnostmi, důležitými pro technologické zpracování do léčivého přípravku. Lékárník by měl modifikovat složení předepsaného přípravku, co se týká pomocných látek, a zvolit takový postup přípravy, aby pacient dostal nejen lék účinný a stabilní, ale i lék o konzistenci vhodné pro předepsaný způsob dávkování a aplikace.
Cellulose derivatives, gelatin, and carbomers are the most used excipients for extemporaneous preparation of mucilages and gels. This article discusses the cellulose derivatives. The pharmacopoeial and best known brand names, the essential physico-chemical properties, viscosity values of 2 % water dispersions, dispersion techniques are specified, also some examples of the wrong prescriptions still used in practice are mentioned. Cellulose derivatives should be named according the pharmacopoeia, not using the brand name, and delivered to the pharmacy with a declared value of viscosity, furthermore other characteristics important for compounding of mucilages and gels. Regarding the excipients the pharmacist should modify the prescriptions and choose such procedure of compounding to get not only the effective and stable drug, but also the preparation of the consistency suitable for the prescribed method of dispensing and way of application.
139 s. : il.,tab.
Celulózové materiály nebo jejich deriváty nabízejí pro hojení ran řadu cenných vlastností. Karboxylované celulózy zastupuje pře-devším karboxymethylovaná celulóza a oxidovaná celulóza. Hcel HT (karboxymethylovaná celulóza) je nový typ celulózového krytí s kyselým povrchovým pH.
In this research, influence of storage conditions on properties of oxidized cellulose was studied with respect to its haemostatic function. The aim was to examine changes of the properties of oxidized cellulose stored properly and that stored at laboratory conditions for 2 years. We studied surface morphology and chemical composition, as well as absorption of the simulated body fluid, behaviour in aqueous environment via potentiometric measurement of pH, and antimicrobial activity in vitro on the S. epidermidis bacteria. It was found out that the material properties of oxidized cellulose did not deteriorate. Higher absorption of simulated body fluid, lower pH in water and simulated body fluid represented positive changes with respect to the haemostatic function. Due to the acidic nature of the mate-rial, degraded oxidized cellulose preserved its antibacterial properties.
- MeSH
- antibakteriální látky analýza MeSH
- celulosa oxidovaná * analýza MeSH
- elektronová mikroskopie metody MeSH
- fotoelektronová spektroskopie metody MeSH
- hemostatika analýza MeSH
- řízení kvality MeSH
- skladování léků MeSH
- vystavení vlivu životního prostředí prevence a kontrola MeSH
- Publikační typ
- klinická studie MeSH
- práce podpořená grantem MeSH
Today, numerous studies have focused on the design of novel scaffolds for tissue engineering and regenerative medicine applications; however, several challenges still exist in terms of biocompatibility/cytocompatibility, degradability, cell attachment/proliferation, nutrient diffusion, large-scale production, and clinical translation studies. Greener and safer technologies can help to produce scaffolds with the benefits of cost-effectiveness, high biocompatibility, and biorenewability/sustainability, reducing their toxicity and possible side effects. However, some challenges persist regarding their degradability, purity, having enough porosity, and possible immunogenicity. In this context, naturally derived cellulose-based scaffolds with high biocompatibility, ease of production, availability, sustainability/renewability, and environmentally benign attributes can be applied for designing scaffolds. These cellulose-based scaffolds have shown unique mechanical properties, improved cell attachment/proliferation, multifunctionality, and enhanced biocompatibility/cytocompatibility, which make them promising candidates for tissue engineering applications. Herein, the salient developments pertaining to cellulose-based scaffolds for neural, bone, cardiovascular, and skin tissue engineering are deliberated, focusing on the challenges and opportunities.
Organic matter decomposition in the globally widespread coniferous forests has an important role in the carbon cycle, and cellulose decomposition is especially important in this respect because cellulose is the most abundant polysaccharide in plant litter. Cellulose decomposition was 10 times faster in the fungi-dominated litter of Picea abies forest than in the bacteria-dominated soil. In the soil, the added (13)C-labelled cellulose was the main source of microbial respiration and was preferentially accumulated in the fungal biomass and cellulose induced fungal proliferation. In contrast, in the litter, bacterial biomass showed higher labelling after (13)C-cellulose addition and bacterial biomass increased. While 80% of the total community was represented by 104-106 bacterial and 33-59 fungal operational taxonomic units (OTUs), 80% of the cellulolytic communities of bacteria and fungi were only composed of 8-18 highly abundant OTUs. Both the total and (13)C-labelled communities differed substantially between the litter and soil. Cellulolytic bacteria in the acidic topsoil included Betaproteobacteria, Bacteroidetes and Acidobacteria, whereas these typically found in neutral soils were absent. Most fungal cellulose decomposers belonged to Ascomycota; cellulolytic Basidiomycota were mainly represented by the yeasts Trichosporon and Cryptococcus. Several bacteria and fungi demonstrated here to derive their carbon from cellulose were previously not recognized as cellulolytic.
- MeSH
- Bacteria genetika izolace a purifikace metabolismus MeSH
- biomasa MeSH
- celulosa metabolismus MeSH
- DNA bakterií izolace a purifikace MeSH
- DNA fungální izolace a purifikace MeSH
- geny hub MeSH
- houby genetika izolace a purifikace metabolismus MeSH
- izotopy uhlíku analýza MeSH
- polymorfismus délky restrikčních fragmentů MeSH
- půda MeSH
- půdní mikrobiologie MeSH
- sekvenční analýza DNA MeSH
- smrk mikrobiologie MeSH
- stromy mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
