Search results for "Microcrystalline cellulose"

2019

Abstract. We present the laboratory results of immersion freezing efficiencies of cellulose particles at supercooled temperature ( T) conditions. Three types of chemically homogeneous cellulose samples are used as surrogates that represent supermicron and submicron ice-nucleating plant structural polymers. These samples include microcrystalline cellulose (MCC), fibrous cellulose (FC) and nanocrystalline cellulose (NCC). Our immersion freezing dataset includes data from various ice nucleation measurement techniques available at 17 different institutions, including nine dry dispersion and 11 aqueous suspension techniques. With a total of 20 methods, we performed systematic accuracy and precis…

Effects of different cellulose derivatives on drug release mechanism studied at a preformulation stage

2003

As a matter of fact, in vitro dissolution is well known to be the method of choice for the pharmaceutical industry to develop effective medicines. However, many experiments must be performed all along a new product life and they represent an overcharge of work for researchers. The purpose of this paper was to assess the relevance of new parameters obtained during preformulation stage by Nuclear Magnetic Resonance (NMR) experiments to better understand drug release mechanism. This study was carried out with three cellulose derivatives currently used as carrier matrices (Microcrystalline cellulose (MCC), Hydroxypropylmethyl cellulose (HPMC) and Ethyl cellulose (EC)). Granules and tablets were…

Preformulation: Effect of Moisture Content on Microcrystalline Cellulose (Avicel PH-302) and Its Consequences on Packing Performances

1999

This study evaluates the influence of moisture content on the packing performances of a new grade of microcrystalline cellulose (MCC) (Avicel PH-302) either by classical method or by an unconventional compression technique (constant volume reduction of powder bed). An increase in moisture content decreases the apparent density of the powder bed, resulting from interparticulate friction enhancement. This modification of apparent density seems to be the main effect caused by the presence of humidity, which explains the variations of compression properties, like an increase of powder plasticity generally observed in the experimental conditions.

Designing robust immediate release tablet formulations avoiding food effects for BCS class 3 drugs

2019

Abstract Food induced viscosity in the gastrointestinal tract is reported to reduce the bioavailability of tablets containing BCS class 3 drugs, mainly by retarding their disintegration and dissolution of the active pharmaceutical ingredient. The role of formulation factors in minimizing this negative food effect is largely unknown. Combinations of disintegrants were studied together with soluble and insoluble fillers and trospium chloride as model drug substance. Different batches of tablets were compressed at 10 kN and 30 kN, by incorporating different combinations of croscarmellose sodium (CSS), cross-linked (CPD) and sodium starch glycolate (SSG) at low level i.e, 2% + 2% and high level…

PBAT Based Composites Reinforced with Microcrystalline Cellulose Obtained from Softwood Almond Shells

2021

This study explores the processability, mechanical, and thermal properties of biocompostable composites based on poly (butylene adipate-co-terephthalate) (PBAT) as polymer matrix and microcrystalline cellulose (MCC) derived from softwood almond (Prunus dulcis) shells (as-MCC) as filler at two different weight concentration, i.e., 10 wt% and 20 wt%. The materials were processed by melt mixing and a commercial MCC (c-MCC) was used as filler comparison. The fibrillar shape of as-MCC particles was found to change the rheological behavior of PBAT, particularly at the highest concentration. The melt mixing processing allowed obtaining a uniform dispersion of both kinds of fillers, slightly reduci…

RHEOLOGICAL BEHAVIOUR OF MICROCRYSTALLINE CELLULOSE HYDROGELS

1992

ABSTRACT An extensive study was made of the rheological behaviour of microcrystal1ine cellulose-sodium carboxymethyl cellulose (MCC-NaCMC) gels at six different concentrations. The effect of agitation time, storage time, shear rate and temperature on the viscosity of these thixotropic gels was analysed, over 7200 resulting values of being available to this effect The pseudoplastic and thixotropic characteristics of the gels was established and a progressive decrease in gel viscosity with increasing storage time was observed, although retaining stability. On the other hand, constant agitation for five minutes was found to reduce gel viscosity by 40 to 50%, regardless of concentration.

Commercial essential oils: sustainable alternatives in the agri-food industry

2019

Essential oils have enjoyed great popularity from ancient times to today due to agreeable scent and widely known beneficial properties. As a result, nowadays they have become valuable natural ingredients in perfume and cosmetics, food and beverages, agricultural, pharmaceutical and other industries for employment in human health, agriculture and environment, representing potentially safer and more sustainable alternatives to synthetic substances. This Doctoral Thesis has been developed with the aim of corroborating that essential oils are safer and more sustainable alternatives to synthetic products used in the agri-food industry, and consequently promoting their use as “bio” products to ma…

Reinforcement Efficiency of Cellulose Microfibers for the Tensile Stiffness and Strength of Rigid Low-Density Polyurethane Foams

2020

Rigid low-density closed-cell polyurethane (PU) foams are widely used in both thermal insulation and structural applications. The sustainability of PU foam production can be increased by using bio-based components and fillers that ensure both enhanced mechanical properties and higher renewable material content. Such bio-based foams were produced using polyols derived from rapeseed oil and microcrystalline cellulose (MCC) fibers as filler. The effect of MCC fiber loading of up to 10 wt % on the morphology, tensile stiffness, and strength of foams has been evaluated. For estimation of the mechanical reinforcement efficiency of foams, a model allowing for the partial alignment of filler fibers…

Cellulose-click-ferrocenes as docking spots for cyclodextrin

2012

A novel synthesis of ferrocene-modified cellulose, prepared from 6-azido-6-deoxy-cellulose and ethynylferrocene, is presented. The two components were coupled via copper-catalyzed click-type cycloaddition under microwave-assisted conditions. The surface structure of the cellulose derivative was investigated in comparison with that of pure, microcrystalline cellulose using electron microscopy (scanning, transmission and scanning transmission), showing iron atoms of ferrocene as homogeneously distributed particles. They are detectable as clear signals in the energy-dispersive X-ray profile. In addition, Rame-β-cyclodextrin was supramolecularly attached to cellulose and the complex formed was …