Particle Size Of Microcrystalline Cellulose Research Articles

Synthesis of Microcrystalline Cellulose from Carpenter Waste and Its Characterizations

ABSTRACT Carpenter waste has been used as a raw material for synthesizing microcrystalline cellulose through various chemical pre-treatment process sequences. Carpenter waste treated with 10% (w/v) sodium hydroxide followed by various concentration of sodium chlorite (0.5%, 0.7%, and 1.0%) treatment has resulted in substantial loss in weight. The synthesized microcrystalline cellulose has been characterized by different instrumental analysis. FT-IR data showed the successful removal of hemicellulose and lignin from the carpenter waste after various chemical treatments. Wide-angle X-ray diffraction analysis is done to measure the crystallinity index and crystal size of the synthesized microcrystalline cellulose. The microcrystalline cellulose produced under different concentrations of sodium chlorite exhibits crystallinity index in the range of 67.56 to 68.85 and calculated average crystal size within the range of 6.47–6.60 nm. The calculated average particle size of microcrystalline cellulose ranges from 96.42 to 437.83 nm depending on the treatment conditions. Higher concentration of sodium chlorite treatment has led to lowering the particle size. Scanning Electron Microscopic image of microcrystalline cellulose shows curled and soft-flat shaped with rough pits and fibrillated network structure. Field Emission Scanning Electron Microscopic analysis reveals the cylindrical rod-shaped morphology and porous structure of the synthesized microcrystalline cellulose from carpenter waste.

Mechanical performance and biodegradability of polyvinyl alcohol nanocomposite films

AbstractThis study investigated the mechanical properties and biodegradability of polyvinyl alcohol (PVA) composite films. 3 wt.%, 5 wt.%, and 10 wt.% microcrystalline cellulose (MCC), commercial grade cellulose nanocrystals (NCCA), and nanocellulose (NCCB) extracted from oil palm fiber (OPF) were incorporated into polyvinyl alcohol by solvent casting. Field emission scanning electron microscopy (FESEM) images indicated that the average particle size of microcrystalline cellulose, commercial grade cellulose nanocrystals, and nanocellulose extracted from oil palm fiber are 12.63 μm±5.71 μm, 502.92 nm±196.10 nm, and 79.20 nm±11.69 nm, respectively. Nanofillers dispersed uniformly in polyvinyl alcohol matrix. Addition of microcrystalline cellulose up to 5 wt.% was able to improve the ultimate tensile strength (UTS) and yield strength of polyvinyl alcohol composite films but sacrificed the maximum elongation. Incorporation of 5 wt.% nanocellulose extracted from oil palm fiber is able to increase ultimate tensile strength, yield strength, and elastic modulus while maintaining the maximum elongation of polyvinyl alcohol composite films. Incorporation of commercial grade cellulose nanocrystals (up to 10 wt.%) increases ultimate tensile strength, yield strength, and maximum elongation while maintaining elastic modulus of polyvinyl alcohol composite films. Soil burial test result found that presence of moisture accelerated the degradation of the polyvinyl alcohol composite films drastically; the films were fully dissolved in the soil after 7 days. However, the weight of polyvinyl alcohol composite films did not change significantly after 28 days under controlled condition. This indicated that soil moisture is an important catalyst in biodegradation activity of polyvinyl alcohol composite films. Comparison with a commercially available biodegradable plastic bag (Bio‐PB) shows that the polyvinyl alcohol composite films developed in this study have superior mechanical performance and biodegradability, with potential to replace existing plastic bags.

Development of green composites of poly (vinyl alcohol) reinforced with microcrystalline cellulose derived from sago seed shells

Reinforcing poly(vinyl alcohol) (PVA) with biopolymers like microcrystalline cellulose (MCC) provides interesting route for the preparation of green composites. In this study, PVA and MCC from sago seed shell in different weight% were prepared by intense sonication followed by solution casting into glass plate. Composites were prepared by adding 1, 2 and 3 weight% of MCC, which were characterized using FTIR, ATR‐FTIR, XRD, TGA, DSC, SEM, AFM, UV‐Vis, and mechanical testing. Particle size distribution of used MCC was analyzed by DLS. ATR‐FTIR spectra reveal the incorporation of MCC into the polymer matrix through hydrogen bonding. XRD pattern shows the decrease in relative intensity compared to PVA film and broadening of peaks at different MCC concentrations. DSC analysis reveals the variations in the glass transition temperature. In addition to lowering in melting temperature, changes in shape and area are attributed to the different degrees of crystallinity due to the existence of polymer‐polymer interactions between PVA and MCC. The results obtained from ATR‐FTIR, XRD and DSC substantiate each other. TGA results reveal the increased thermal stability compared to the PVA film. The SEM analysis shows the uniform distribution for lower loading, which is further supported by AFM. UV‐Visible spectra reveal the good transparency of prepared films. Mechanical testing was also performed, in which 1 weight% gained tensile strength. The TGA and mechanical testing results showed that MCC as reinforcement in PVA film can improve thermal and mechanical strength. DLS measurements show that the particle size of MCC is >100 nm. POLYM. COMPOS., 39:3033–3039, 2018. © 2017 Society of Plastics Engineers

Influence of starting material particle size on pellet surface roughness.

The purpose of this study was to investigate the effect of pelletization aids, i.e., microcrystalline cellulose (MCC) and cross-linked polyvinyl pyrrolidone (XPVP), and filler, i.e., lactose, particle size on the surface roughness of pellets. Pellets were prepared from powder blends containing pelletization aid/lactose in 1:3 ratio by extrusion-spheronization. Surface roughness of pellets was assessed quantitatively and qualitatively using optical interferometry and scanning electron microscopy, respectively. Both quantitative and qualitative surface studies showed that surface roughness of pellets depended on the particle size of XPVP and lactose used in the formulation. Increase in XPVP or lactose particle size resulted in rougher pellets. Formulations containing MCC produced pellets with smoother surfaces than those containing XPVP. Furthermore, surface roughness of the resultant pellets did not appear to depend on MCC particle size. Starting material particle size was found to be a critical factor for determining the surface roughness of pellets produced by extrusion-spheronization. Smaller particles can pack well with lower peaks and valleys, resulting in pellets with smoother surfaces. Similar surface roughness of pellets containing different MCC grades could be due to the deaggregation of MCC particles into smaller subunits with more or less similar sizes during wet processing. Hence, for starting materials that deaggregate during the wet processing, pellet surface roughness is influenced by the particle size of the material upon deaggregation.

Modeling pharmaceutical compacts tensile strength based on viscoelastic properties

Abstract Although several researchers acknowledge the effects of viscoelasticity in pharmaceutical powder compaction, no models have been reported that relate compact mechanical properties to the powder viscoelastic properties. The tensile strength of a compact is largely influenced by contact area between deforming particles which depends on the viscoelastic properties and compaction variables. The objective of this research was to develop semi-mechanistic models based on viscoelastic contact area estimates, to predict tensile strength of Microcrystalline Cellulose (MCC) and Acetaminophen (APAP) compacts. Formulations with varying amounts of MCC, APAP and moisture contents corresponding to 50 and 70% RH were prepared. The powders were compressed in a Uniaxial testing machine (Instron) at a punch velocity of 2 mm/min to final pressures in the range of 12.5 to 44 MPa. The diametral tensile strength, compaction and viscoelastic properties were determined. The deformation contact area was estimated using equation by Lum and Duncan-Hewitt [22] based on the median particle size of MCC, compaction and viscoelastic properties as determined from the Maxwell model. It was found that the estimated contact area depended on the APAP composition, moisture content and on compaction pressure. The viscoelastic contact area, density and final compact tensile strength were found to increase with increasing compaction pressure, moisture content and MCC. A unified model that expresses the compact tensile strength as a function of viscoelastic contact area was successfully developed.

Examining the Impact of Excipient Material Property Variation on Drug Product Quality Attributes: A Quality-By-Design Study for a Roller Compacted, Immediate Release Tablet

A quality-by-design study examining the impact of variability in excipient material properties on the quality attributes of an immediate release tablet was performed. A literature review and risk analysis identified particle size of microcrystalline cellulose (MCC), spray-dried lactose (SDL), and magnesium stearate (MgSt), and polymorph and specific surface area of MgSt as potential high-risk material properties. The following results were obtained with laboratory-scale processing equipment: (1) a 32-µm increase in d(50) (mean particle diameter) of MCC and SDL led to a ∼ 30-µm increase in blend and granulation d(50) and a statistically significant increase in the blend and granulation flow function coefficients, and (2) a 32-µm increase in d(50) of MCC and SDL, a 4.4 m(2)/g increase in the surface area, and a 19-µm decrease in the particle size of MgSt yielded an 18%-28% increase in ribbon tensile strength and tablet hardness. Confirmatory experiments with kilo-scale equipment showed impact of excipient variability on granulation particle size and tablet hardness was ∼ 50% smaller. Although the impact of these differences on overall manufacturability and performance of the tablets examined here were deemed low, the presence of statistically significant effects supports examining excipient variability as part of the design and control strategy of new drug products.

Instrumentation of a Gravity Feed Extruder and the Influence of the Composition of Binary and Ternary Mixtures on the Extrusion Forces

A gravity feed extruder was adapted to monitor the extrusion forces, the temperature during processing and the rotational speed of the extruding cylinders. The extruder was used to evaluate the influence of particle size of insoluble material and of product solubility on the extrusion forces. Microcrystalline cellulose, dicalcium phosphate dihydrate and different lactoses were used as model compounds. Difference in lactose and microcrystalline cellulose particle size did not influence extrusion forces. The amount of water in the mixtures to be processed and the initial difference in solubility for some of the lactose types investigated influenced the extrusion forces dramatically. Extrusion forces recorded during processing of a mixture previously granulated in a high shear granulator were higher than when processed in a planetary mixture. Loss of water during high shear granulation is probably the main cause of this phenomenon.

Effects of particle size and cohesive properties on mixing studied by non-contact NIR

A scaled-down convective blender was used along with non-invasive NIR spectrometry to study the mixing of citric acid, aspirin, aspartame or povidone with microcrystalline cellulose. NIR mixing profiles were generated in real time using measurements at the 2nd overtone wavelength of the added compounds. Trends demonstrated previously for aspirin were confirmed for additions of citric acid: the magnitude of the 2nd overtone NIR measurements is less affected by changes in particle size than that of the 1st overtone; the peak-to-peak noise of the 2nd overtone NIR mixing profile increases with the particle size of the added compound. The study has demonstrated the usefulness of continuous NIR measurements for rapid evaluation of the mixing process when deciding the best particle size of microcrystalline cellulose to mix with compounds of different particle shape and cohesive properties. Smaller particle sizes of microcrystalline cellulose (53–106 μm) were better for aspirin (212–250 μm), whereas larger particles (212–250 μm) were better for aspartame (212–250 μm). The characteristics of the compounds also need to be considered when deciding the order of addition of secondary compounds when mixed with microcrystalline cellulose. The time required to achieve a uniform mixture was much less when povidone was added before aspirin, rather than vice versa.

Direct pelletization in a rotary processor controlled by torque measurements. III. Investigation of microcrystalline cellulose and lactose grade

The aim of the present study was to investigate the use of different grades of microcrystalline cellulose (MCC) and lactose in a direct pelletization process in a rotary processor. For this purpose, a mixed 2- and 3-level factorial study was performed to determine the influence of the particle size of microcrystalline cellulose (MCC) (approximately 60 and 105 microm) and lactose (approximately 30, 40, and 55 microm), as well as MCC type (Avicel and Emcocel) on the pelletization process and the physical properties of the prepared pellets. A 1:4 mixture of MCC and lactose was applied, and granulation liquid was added until a 0.45 Nm increase in the torque of the friction plate was reached. All combinations of the 3 factors resulted in spherical pellets of a high physical strength. The particle size of MCC was found to have no marked effect on the amount of water required for agglomerate growth or on the size of the resulting pellets. An increasing particle size of lactose gave rise to more spherical pellets of a more narrow size distribution as well as higher yields. The MCC type was found to affect both the release of the model drug from the prepared pellets and the size distribution. Generally, the determined influence of the investigated factors was small, and direct pelletization in a rotary processor was found to be a robust process, insensitive to variations in the particle size and type of MCC and the particle size of lactose.

PERCEPTION OF GRITTINESS IN AN OIL‐IN‐WATER EMULSION

ABSTRACTMicrocrystalline cellulose was dispersed as a gritty substance in an emulsion, and sensory evaluation was conducted to examine the effect of the presence of oil on grittiness felt in the mouth. Samples were prepared with three types of microcrystalline cellulose of average particle size 14, 38, and 76 μm and with a concentration in water of 0.03–2.7%, with three types of emulsion with an oil‐volume fraction of 0.2–0.7, and with three rates of homogenization of 500–15,000 rpm. The flow behavior and loss modulus of each sample were measured and sensory evaluation was made of the perceived grittiness. A multiple regression analysis of the data shows that the proportion of people who could perceive grittiness was influenced by the following factors and in that order: concentration of microcrystalline cellulose, oil droplet size, loss modulus, and particle size of microcrystalline cellulose. The proportion of people who perceived grittiness also increased with increasing oil droplet size. This was conceivably caused by the uneven distribution of microcrystalline cellulose particles promoted by large oil droplets. An equation was developed relating the proportion of people perceiving grittiness to the physical properties of the sample. The result indicates that factors effecting grittiness perception are identical for emulsions, aqueous suspensions, viscous suspensions and gels, studied previously.

The effect of the particle size of microcrystalline cellulose on tablet properties in mixtures with magnesium stearate

Magnesium stearate was mixed with different sieved fractions (80–180, 180–250, 250–350 μm) of microcrystalline cellulose (Avicel PH 102). The influence of mixing time on crushing strength and disintegration of tablets compressed from these mixtures were studied. The disintegration time increased and the crushing strength decreased with increasing particle size of the Avicel fractions. When magnesium stearate is mixed with table excipients the size of these materials could have an effect on the deterioration of the tablet properties as a function of mixing time.

Adsorption—desorption effect of microcrystalline cellulose on ampicillin and amoxycillin

Three grades of microcrystalline cellulose (Avicel PH 105, 103 and 102) were used to elucidate their effects on both ampicillin monohydrate and amoxycillin trihydrate, both in water and in 0.1 N HCl media. The studies were undertaken to determine the effect of specific surface area, pH as well as the type of antibiotic on the adsorptive capacity of microcrystalline cellulose. In addition, desorption of the antibiotics from the adsorbate was carried out in distilled water and in 0.1 N HCl solution at various elution stages. The minimum inhibitory concentration (MIC) and minimum biocidal concentration (MBC) were determined against the standard sensitive test microorganism ( Sarcina lutea ATCC 9341) for each of the selected antibiotics in absence and presence of each of the microcrystalline cellulose grades. Studies revealed that the smaller the particle size of microcrystalline cellulose the more drug was adsorbed, a property which is more apparent in aqueous ampicillin solution while amoxycillin was highly adsorbed in acid solution. Higher rates of antibiotic elution were obtained in acid solutions than in aqueous media. Amoxycillin showed higher elution relative to ampicillin to the extent of complete desorption in gastric pH solution. The MIC of the tested antibiotics increased in presence of microcrystalline cellulose with decreased particle size.