Moisture sorption and tensile strength of some tableted direct compression excipients

1991 ◽  
Vol 68 (1-3) ◽  
pp. 51-60 ◽  
Author(s):  
S. Malamataris ◽  
P. Goidas ◽  
A. Dimitriou
Keyword(s):  
Tensile Strength ◽  
Moisture Sorption ◽  
Direct Compression

scholarly journals Evaluation of Chitosan-Microcrystalline Cellulose Blends as Direct Compression Excipients

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Emmanuel O. Olorunsola ◽  
Grace A. Akpan ◽  
Michael U. Adikwu
Keyword(s):  
Tensile Strength ◽  
Dissolution Rate ◽  
Microcrystalline Cellulose ◽  
Extended Release ◽  
Moisture Sorption ◽  
Direct Compression ◽  
Disintegration Time ◽  
Lactose Monohydrate ◽  
Compact Density ◽  
Tablet Disintegration

This study was aimed at evaluating chitosan-microcrystalline cellulose blends as direct compression excipients. Crab shell chitosan, α-lactose monohydrate, and microcrystalline cellulose powders were characterized. Blends of the microcrystalline cellulose and chitosan in ratios 9 : 1, 4 : 1, 2 : 1, and 1 : 1 as direct compression excipients were made to constitute 60% of metronidazole tablets. Similar tablets containing blends of the microcrystalline cellulose and α-lactose monohydrate as well as those containing pure microcrystalline cellulose were also produced. The compact density, tensile strength, porosity, disintegration time, and dissolution rate of tablets were determined. Chitosan had higher moisture content (7.66%) and higher moisture sorption capacity (1.33%) compared to microcrystalline cellulose and lactose. It also showed better flow properties (Carr’s index of 18.9% and Hausner’s ratio of 1.23). Compact density of tablets increased but tensile strength decreased with increase in the proportion of chitosan in the binary mixtures. In contrast to lactose, the disintegration time increased and the dissolution rate decreased with increase in the proportion of chitosan. This study has shown that chitosan promotes flowability of powder mix and rapid disintegration of tablet. However, incorporation of equal proportions of microcrystalline cellulose and chitosan leads to production of extended-release tablet. Therefore, chitosan promotes tablet disintegration at low concentration and enables extended-release at higher concentration.

scholarly journals IX. On the existence of an element of strength in beams subjected to transverse strain, arising from the lateral action of the fibres or particles on each other, and named by the author the 'resistance of flexture.’

1855 ◽  
Vol 145 ◽  
pp. 225-242
Keyword(s):  
Tensile Strength ◽  
Cast Iron ◽  
Neutral Axis ◽  
Direct Compression ◽  
Transverse Strain ◽  
Direct Tension ◽  
Direct Tensile ◽  
Direct Tensile Strength

It has been long known, that under the existing theory of beams, which recognizes only two elements of strength, namely, the resistances to direct compression and extension, the strength of a bar of cast iron subjected to transverse strain cannot be reconciled with the results obtained from experiments on direct tension, if the neutral axis is in the centre of the bar. The experiments made both on the transverse and on the direct tensile strength of this material have been so numerous and so carefully conducted, as to admit of no doubt of their accuracy; and it results from them, either that the neutral axis must be at, or above, the top of the beam, or there must be some other cause for the strength exhibited by the beam when subjected to transverse strain.

Unified compaction curve model for tensile strength of tablets made by roller compaction and direct compression

2008 ◽  
Vol 346 (1-2) ◽  
pp. 17-24 ◽  
Author(s):  
Leon Farber ◽  
Karen P. Hapgood ◽  
James N. Michaels ◽  
Xi-Young Fu ◽  
Robert Meyer ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Roller Compaction ◽  
Direct Compression ◽  
Curve Model ◽  
Compaction Curve

scholarly journals Acrylate/Nanofibrillated Cellulose Nanocomposites and Their Use for Paper Coating

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Mohammad L. Hassan ◽  
Shaimaa M. Fadel ◽  
Enas A. Hassan
Keyword(s):  
Tensile Strength ◽  
Water Absorption ◽  
Moisture Sorption ◽  
Nanofibrillated Cellulose ◽  
Strength Properties ◽  
Thermomechanical Properties ◽  
Thin Layers ◽  
Moderate Increase ◽  
Paper Coating ◽  
Acrylate Polymer

Nanofibrillated cellulose (NFC) isolated from TEMPO-oxidized rice straw was used to improve thermal and tensile strength properties of acrylate polymer films. Acrylate/NFC mixture containing 15% NFC was used for paper coating, and properties of paper sheets including tensile strength, water absorption, and microscopic structure were investigated. The results showed that the presence of NFC in the acrylate matrix significantly improved tensile strength properties and thermomechanical properties of the acrylate polymer and caused moderate increase in its moisture sorption. The presence of NFC in acrylate emulsion caused significant increase in its viscosity. Paper sheets coated with different thin layers (from 0.2 to 6 microns) of acrylate/NFC showed improvement in tensile strength and decrease of water absorption.

scholarly journals Evaluation and Comparison of Three Types of Spray Dried Coprocessed Excipient Avicel® for Direct Compression

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Pavlína Vodáčková ◽  
Barbora Vraníková ◽  
Petra Svačinová ◽  
Aleš Franc ◽  
Jan Elbl ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Negative Charge ◽  
Electrostatic Charge ◽  
Direct Compression ◽  
Nonspherical Particles ◽  
Flow Properties ◽  
Sem Images ◽  
Pycnometric Density ◽  
Ejection Force ◽  
Spray Dried

As coprocessed excipients (CPE) gain a lot of focus recently, this article compares three commercially available CPE of Avicel brand, namely, CE 15, DG, and HFE 102. Comparison is based on measured physical properties of coprocessed mixtures, respectively, flow properties, pycnometric density, mean particle size, specific surface area, moisture content, hygroscopicity, solubility, pH leaching, electrostatic charge, SEM images, and DSC. Tablets were made employing three pressure sets. Viscoelastic properties and ejection force were assessed during compression, as well as pycnometric density, mass uniformity, height, tensile strength, friability, disintegration, and wetting times. Avicel CE 15 is of mid-range flow properties, contains mid-size and nonspherical particles, and has high hygroscopicity, growing negative charge, best lubricity, lowest tensile strength, and mid-long disintegration times. Avicel DG possesses the worst flow properties, small asymmetrical particles, lowest hygroscopicity, stable charge, intermediate lubricity, and tensile strength and exhibits fast disintegration of tablets. Finally, Avicel HFE 102 has the best flow properties, large symmetrical particles, and middle hygroscopicity and its charge fluctuates throughout blending. It also exhibits inferior lubricity, the highest tensile strength, and slow disintegration of tablets. Generally, it is impossible to select the best CPE, as their different properties fit versatile needs of countless manufacturers and final products.

Effects of Feed Powder Quantity and Compression Pressure on the Tensile Strength of Eurycoma longifolia Jack Tablets Using Different Binders

2013 ◽  
Vol 9 (2) ◽  
pp. 155-161
Author(s):  
Aziana Azlin Abdul Hamid ◽  
Yus Aniza Yusof ◽  
Nyuk L. Chin ◽  
Suhaila Mohamed ◽  
Faiqa Salleh
Keyword(s):  
Tensile Strength ◽  
Binary Mixtures ◽  
Linear Trend ◽  
Direct Compression ◽  
Compression Pressure ◽  
Eurycoma Longifolia ◽  
Compression Properties ◽  
Compression Speed ◽  
Eurycoma Longifolia Jack ◽  
Diametral Compression Test

AbstractThis study investigated the direct compression properties of Eurycoma longifolia Jack tablets using binary mixtures such as microcrystalline cellulose (mcc) and κ-carrageenan (carr). The mixtures were compacted to various compression pressures ranging from 7.5 to 74 MPa at a constant compression speed of 5 mm/min. The tensile strengths of the tablets were determined by a diametral compression test. A linear relationship between the tensile strength and the compression pressure was observed under the conditions of the test; hence, the slopes of the data were obtained by fitting linear trend lines. This paper shows that binary mixtures of 30% mcc and 70% Eurycoma longifolia Jack give the highest values for constant (a slope) compared with the other binary mixtures of both binders. Thus, this approach can be used to develop formulations for Eurycoma longifolia Jack tablets.

Physical properties of lyocell-reinforced polypropylene composites from intermingled fibre with varying fibre volume fractions

2017 ◽  
Vol 31 (8) ◽  
pp. 1029-1041 ◽  
Author(s):  
Michael Cordin ◽  
Thomas Bechtold
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance ◽  
Raw Materials ◽  
Moisture Sorption ◽  
Cellulose Fibre ◽  
Fibre Volume ◽  
Textile Fibre ◽  
Cellulose Fibres ◽  
Cellulose Composites

Polypropylene (PP)-cellulose fibre blends exhibit substantial potential for the production of high-performance textile fibre–reinforced composites. The production of reinforced parts from PP-cellulose composites through thermal shaping of intermingled fibre blends is a strategy to form parts which exhibit superior mechanical properties. In this study, the use of intermingled fibre slivers with different ratios of lyocell fibres (CLY) and PP fibres as raw materials for thermally formed composites was investigated. Such a concept will maximize the interface between the reinforcement fibres and polymer matrix. The cellulose fibres remain oriented along the direction in which the drawing process was performed, which forms the basis for tailored fibre placement in technical production. Because of good surface contact between the cellulose fibre surface and PP matrix, no special coupling agents were required to improve the interfacial adhesion between the two different polymers. The share of CLY and PP fibres in the composite varied from 50% w/w CLY content, up to 70% w/w CLY. Besides analysis of the mechanical properties, such as tensile strength and E-modulus, attention was directed towards moisture sorption of the composites. The rate of sorption and amount of water bound in the composite were found to be dependent on the cellulose fibre content. Composites with a higher CLY content exhibited a more rapid and higher moisture uptake. In water saturated state, the ultimate tensile strength of composites reduced from 160 MPa to 90 MPa, which is an indicator for a reduced adhesion between the CLY surface and PP matrix. The results indicate the potential of the intermingled fibre concept blend for the efficient manufacturing of composite parts.

scholarly journals Development of extended-release formulation of domperidone using a blend of Raphia hookeri gum and hydroxypropyl methylcellulose as tablet matrix

2017 ◽  
Vol 16 (10) ◽  
pp. 2341-2347
Author(s):  
Emmanuel O. Olorunsola ◽  
Stephen O. Majekodunmi
Keyword(s):  
Tensile Strength ◽  
Drug Release ◽  
Extended Release ◽  
Hydroxypropyl Methylcellulose ◽  
Direct Compression ◽  
Release Formulation ◽  
Extended Release Formulation ◽  
Raphia Hookeri ◽  
The Matrix ◽  
The Individual

Purpose: To develop an extended-release formulation of domperidone using a blend of Raphia hookeri gum and hydroxypropyl methylcellulose as tablet matrix.Methods: Tablets (400 mg) containing 30 mg domperidone (DPD) were formulated using binary mixtures of hydroxypropyl methylcellulose (HPMC) and Raphia hookeri gum (RHG) as matrix former; and microcrystalline cellulose (MCC) as direct compression excipient. The proportions of the matrix formers (40 % of tablet weight) was varied as 100:0, 75:25, 50:50, 25:75 and 0:100. The composition of the matrix former was also kept constant (50:50) while MCC was varied as 40, 30, 20 and 10 %. The tablets were evaluated for compact density, tensile strength, friability and drug release over 24 h.Results: The tensile strength of tablets decreased while their friability increased with increase in the proportion of RHG. A similar trend was observed with decrease in the concentration of MCC. Tablets containing RHG alone as matrix former and 40 % MCC as direct compression excipient had tensile strength of 0.95 MNm-2, friability of 1.07 % and cumulative drug release of 83.2 % over a period of 24 h. Tablets containing equal proportions of HPMC and RHG as matrix former had the best release properties of 95.0 % over a period of 24 h.Conclusion: RHG is comparable with HPMC in terms of extending the release of  domperidone for a once daily administration. A suitable combination of the two  polymers for use as a matrix former is superior to either of the individual polymers.Keywords: Domperidone, Extended drug release, Hydroxypropyl methylcellulose, Raphia hookeri gum, Tablet properties

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

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