Crushing Strength Values Research Articles

Study on Strength Characteristics of Granular Materials

Crushing strength of granular material plays vital role in major civil engineering structures like offshore constructions, pile driving, mining under the high stresses. Determining the crushing strength of granular materials and also experimental results get influenced by its size, shape of grains, density, load application, strain rate, and its aspect ratio etc. So, crushing strength value differs from material to material. With this in view, here an attempt is made to determine the crushing strength for different granular materials like Natural River sand, Ennore sand, Glass beads and Geopolymer fly ash sand with specially fabricated mold. All materials are tested and characterized for index and engineering properties and also determined crushing strength by strain controlled digital load frame for different aspect ratios. Similar crushing strength values obtained for 12M Geo-polymer sand compared to other granular materials hence Geopolymer sand as an alternative material to natural river sand. Experimental results are tabulated in the paper.

Investigations on Compaction Behavior of Kollidon®SR-Based Multi-component Directly Compressed Tablets for Preparation of Controlled Release Diclofenac Sodium.

The physics of tablets mixtures has gained much attention lately. The purpose of this work is to evaluate the compaction properties of Kollidon® SR (KSR) in the presence of different excipients such as Microcrystalline cellulose (MCC), Monohydrous lactose (MH Lactose), Poly (vinyl acetate) (PVA100), and a water-soluble drug Diclofenac sodium (DNa) to prepare once daily formulation. Tablets were prepared using direct compression and were compressed into flat-faced tablets using hydraulic press at various pressures. The combination of MCC and KSR in the tablets showed reduced porosity, and almost constant low Py values as KSR levels increased; also, KSR-DNa tablets had higher percentage porosity and crushing strength values than KSR-MH Lactose tablets. The crushing strengths of KSR-MCC tablets were larger than those of KSR-DNa tablets. Ternary mixture tablets comprised of KSR-MCC-DNa showed decreased porosities and low Py values as the percentage of KSR increased especially at high compression pressures but had higher crushing strengths compared to KSR-DNa or MCC-DNa binary tablets. KSR-MH Lactose-DNa ternary tablets experienced lower porosities and crushing strengths compared to KSR-MCC-DNa tablets. Quaternary tablets of KSR-PVA100-MCC-DNa showed lower porosity and Py values than quaternary tablets obtained using similar proportion of MH Lactose instead of MCC. In conclusion, optimum quaternary tablets were obtained with optimum crushing strengths, relatively low Py, and moderate percentage porosities among all prepared quaternary tablets. The drug release of the optimum quaternary tablets demonstrated similar in vitro release profile compared to that of the marketed product with a mechanism of release that follows Korsmeyer-Peppas model.

INFLUENCE OF BINDERS, MIX PROPORTIONS, AND FABRICATION METHOD ON THE CHARACTERISTICS OF FLY ASH AGGREGATE

In this paper, two types of lightweight fly ash (FA) aggregates: cold bonded fly ash (CFA) and sintered fly ash (SFA) aggregates were prepared through the cold bonding and sintering method. During the pelletization process, different ratios of binders to fly ash were used, i.e., 10:90, 15:85, 17:83, and 20:80 with a set amount of water. Cement, metakaolin, sodium silicate, urea-formaldehyde resin, bentonite powder, and phenol-formaldehyde resin were employed as binders. A comparative study on physicochemical, mechanical, phase identification, microstructure, and optical analysis of CFA and SFA was performed. The results showed that CFA (an alkali binder) had a higher water absorption (WA) value of 9,50 % with a crushing strength (CS) value of 6,30 MPa than SFA (sodium silicate binder) with a CS value of 5,80 MPa and a WA value of 10,28 %. Experimental observations also demonstrated that the leaching ability of SFA was considerably lower than that of CFA. Most notably, SFA can be used as a substitute for construction material and structural applications along with solving FA waste disposal and related problems to a considerable extent.

Forsterite refractory brick produced by talc and magnesite from Thailand

This research focuses on refractory material synthesized from precursors of talc and magnesite in Thailand. They were mixed at a molar ratio of 1:5 with mechanical activation at 5 h and calcined at 1300 °C for 1 h to create forsterite. The resulting forsterite crystals were round with less than 1-μm particle size. Synthetic forsterite refractory was formed into refractory bricks and studied at various sintering temperatures of 1200, 1300, and 1400 °C with a dwell time of 2 h. The characteristics and properties of refractory samples were tested in physical properties, cold crushing strength, thermal conductivity, thermal shock, and corrosion resistance from various substances. The results showed that increasing the sintering temperature increases the physical properties and cold crushing strength values. Also, the sintering temperature increases will increase thermal conductivity. The best condition of forsterite refractory brick sintering was 1400 °C for 2 h (FB-14), which showed the following desirable properties: firing shrinkage of 18%, bulk density of 3.03 g/cm3, the apparent density of 3.26 g/cm3, both apparent porous and water absorption values of zero, and cold crushing strength of 72.18 MPa. The FB-14 brick has excellent resistance to corrosion and penetration from lead silicate frit and copper slag. There was minor weight loss from the corrosion of the chemical solutions used in sodium hexametaphosphate production, whereby weight loss will begin on the 18th cycle. Consequently, the FB-14 brick can be used for blast furnace walls to slow down corrosion, which will allow the blast furnace to have a longer life cycle.

Environmental Friendly Lightweight Artificial Aggregates through Industrial Waste Stabilization

The production of lightweight artificial aggregates proposed in this study derives from industrial waste recovery activities, such as fly ash (FA) and ground granulated blast furnace slag. The aim is to reduce the compromise of the environment and human health, through the recycling of special waste. The use of inert aggregates from recovery from industrial waste encourages the reduction of soil consumption, the waste of natural aggregates, consequently limiting the consumption of waste materials from quarries, as well as facilitating the recovery of waste that would inevitably end up in landfilled or abandoned in the environment. Specifically, in the present work, the lightweight artificial aggregates were produced by cold bonding granulation technique. All the mixtures, made by 80% of FA with various composition of cement and granulated blast furnace slag, were characterized by density values ranging from 1.63 to 1.66 g cm-3 suggesting their suitable classification as lightweight aggregates (LWAs). Water absorption capacity (WAC) and open porosity values decreased with the increase of the percentage in cement. The impact test results indicate that all the aggregates have proved to be suitable as filling for road pavements. The best crushing strength values (1.86 MPa) were observed for the mixture contain the highest amount of cement. Aggregate leaching tests indicated a significant release of chlorides and sulphates while the release of heavy metals was lower than the limits set by the standard UNI 10802.

Evaluation of a new grain breakage factor based on the single grain crushing strength

In granular soils subjected to high-level shear stress, a micro-damage occurs in the soil's internal structure, referred to as grain breakage. The main factors controlling grain breakage are the applied stress level and the single grain crushing strength of the individual grains (σf). This paper presents a laboratory study on ballast grains' single grain crushing behavior. Double-plate grain crushing tests were carried out on dolomite, calcerous, and basalt origin grains, having sizes ranging from 2.00 to 37.50 mm. Factors affecting the single grain crushing strength, such as grain shape, loading rate, and grain size, were investigated. Individual grains' single grain crushing strength was observed in three phases related to granular soils' 3-staged one-dimensional compression behavior. An equation that considers grain shape in terms of grain sphericity (form) has been proposed to determine the single grain crushing strength. One-dimensional compression tests were performed on uniformly graded soil samples consisting of calcerous and basalt origin grains. The single grain crushing strength of the calcerous origin soil sample’s mean grain-sized grains was determined to be 12.7 MPa, and this value was determined to be 25.6 MPa for the sample consisting of basalt origin grains. One-third/fourth of this single grain crushing strength value was obtained as the virgin compression line (VCL) initial stress of the soils’ one-dimensional compression curve (4.3 and 6.0 MPa for calcerous and basalt origin soil samples, respectively). The final stress of the VCL was determined to be close to 1–1.25 times of this specified single grain crushing strength (16 and 26 MPa for calcerous and basalt origin soil samples, respectively). The change in the mean grain size of the soil samples (d50) during one-dimensional compression was defined as an exponential function. A new grain breakage factor depending on the single grain crushing strength of the soils’ mean grain-sized grains has been proposed to determine the grain breakage that develops under one-dimensional compressional conditions.

The Effect of Particle Size on the Physical Characteristics and Drug-release Behavior of Mini-tablets

This study aimed to investigate the influence of particle size of the excipients on the behavior of mini-tablets in terms of physical characteristics and drug release profiles. Material and methods: All of the mini-tablets based on HPMC, PEG 6K and PEO 8M PVP produced high quality mini-tablets from both sieve fractions while 90F was very fragile. Results: Crushing strength values were the most pronounced difference between the mini-tablets from all formulations. The PEO 8M-based mini-tablets showed the highest values and deformation behavior instead of fracture. Water absorption and drug release profiles also showed intriguing and different results between the various formulations. Conclusion: The results suggested that even though different particle size has limited effect on the physical characteristic of the product, it may have a significant effect on its drug dissolution profile. HIGHLIGHTS The particle size of powders or granules can influence the physical properties and release profiles of tablets, particularly mini-tablets PEG 6K and PEO 8M mini-tablets from the larger sieve fraction variation absorbed less moisture and released drugs faster than their counterparts, whereas HPMC and PVP 90F mini-tablets from both sieve fractions exhibited a similar pattern in terms of moisture uptake and drug release profiles PEO 8M mini-tablets of both sieve fractions displayed almost linear release profiles with the highest crushing strength than the rest of the formulations GRAPHICAL ABSTRACT

Compressive Strength of a Prescribed Control Mix for High Performance Self-compacting Concrete

Another way of improving concrete production involves incorporating the unique features of high performance concrete with the special properties of self-compacting concrete, resulting in another type of concrete called high performance self-compacting concrete (HPSCC). Many researchers have developed diverse designed control mix for HPSCC which were obtained through several and rigorous designed trial mixes. Yet, little work has been done on prescribed control mix for HPSCC. The purpose of this paper is to establish a prescribed control mix ratio for HPSCC and to test by conducting compressive strength test. Review of the various designed control mix ratios is done in this paper. A logical prescribed control mix ratio of 1:1.02:0.95 has been established for an HPSCC with 0.36 w/c proportion, 0.02 superplasticizer/cement proportion. The compressive strength gave 36.10 MPa at 7 days curing age, 41.76 MPa at 14 days curing age and 57.29 MPa at 28 days curing age. This strength result satisfied the strength criteriaa of HPSCC, according to EFNARC It is therefore recommended that a prescribed control mix of 1:1.02:0.95 be used if the minimum crushing strength value expected at 28 days is 40 N/mm2 for an HPSCC.

Effect of granite weathered granules additives as aggregates in cement concrete

Granitic weathering products were obtained from South Sinai. These aggregates were assessed to be used in the manufacturing of cement concrete. Chemical and mineralogical compositions and physical parameters of the selected samples were carried out. The composition of the main phase is quartz, albite, and microcline, while river sand shows only quartz as one phase. Four batches were designed with two different grain size divisions between the fine to medium granules. Two batches were designed with aggregates of granite weathering products only for all sizes. The other two batches were designed with coarse and medium granite aggregates and a fine of river sand. Some technological characteristics of the four batches in terms of bulk density, expansion, and compressive strength were detected. It is deduced that the replacement of the fine granite weathering products fraction with the river sand in two ratios (10 & 20%) yields higher amounts of the technological properties. The maximum compressive strength results recorded are 101.53% and 180.92%, in the batch nos. 4 and 3, respectively. The batch contains 20% of the river sand, fine fraction is denser and higher expansion and crushing strength values. SEM and EDX of the batches nos. 2 and 3 support the technological properties and the phase composition of the main component of granite and river sand granules as well as the composition of the main oxides of the OPC common in the market and elucidated that the river-sand as fine granules has better technological characteristics than the granite fine granules.

Impact of high temperature on the compression behavior of carbon-bonded alumina filters with functionalized coatings

Carbon-bonded alumina is currently applied in metal casting processes due to its excellent thermomechanical performance. Used as ceramic foam filters in steel casting, the surface composition of such material is essential for trapping primary and secondary inclusions in liquid steel, where functionalized coatings are proven to enhance the filtration efficiency considerably. In this paper, compression tests on uncoated and coated Al2O3–C foam filters are performed at high temperatures under argon atmosphere. The macrostructure of the prepared filters before the high temperature compression tests and the microstructure afterwards are examined by computer tomography and scanning electron microscopy, respectively. High temperature compression strength of the studied filters generally exceeds cold crushing strength values thanks to plastification processes. The applied coatings have positive impact on the filter strength. The observed high scatter of the compression strength can be attributed to the inhomogeneity of strut thickness, distribution of the oxide and non-oxide materials within the struts as well as coating thickness.

A Comparative Evaluation of Fast Dissolving Tablets of Acetaminophen Using Super-disintegrant Blends and Sublimation Method

Fast disintegrating tablets (FDTs) are gaining prominence as drug delivery systems and emerging as one of the popular and widely accepted dosage forms, especially for the peadiatric and geriatric patients. This study aims to evaluate and compare the tablet properties of fast disintegrating tablets of acetaminophen prepared by super-disintegrant blends and sublimation methods. Two groups of tablets comprising various batches were prepared by wet granulation. Granules batches of one group of tablets (A-G) were prepared with different concentrations of sodium starch glycolate and croscarmellose sodium while the other group of tablets (H-N) were incorporated with varying concentrations of menthol into the batches. The granules were subjected to analysis and compressed into tablets. The post-compression parameters of the tablets such as weight uniformity, crushing strength, friability, wetting and disintegration times, as well as dissolution studies were evaluated. Drug-excipient compatibility studies using Fourier transform infrared (FTIR) analysis was also carried out. Granules were fair to good in flow with Carr’s indices ≤ 20.14 and angles of repose ranging from 21.34 to 35.00°. Tablets crushing strength values were between 3.44 to 8.26 kp while their friability values were < 1.52%. They showed wetting and disintegration times that were ≥ 0.18 and ≥ 0.25 min. Dissolution studies showed that four batches of tablets (two from each method used in formulation) achieved 100% drug release within 30 min. FTIR analysis shows no interactions between acetaminophen and excipients used in formulation. Tablets from both methods were comparable in their tablet properties but the disintegrant blend tablets exhibited superior crushing strengths, hence formed harder tablets, while the sublimation method tablets were superior in their wetting and disintegration times.
 Keywords: acetaminophen, super-disintegrants, sublimation, tablet parameters

Strain rate effects on the compressive response of wood and energy absorption capabilities – Part B: Experimental investigation under rigid lateral confinement

The compressive properties of spruce and beech wood species at a large range of strain rates – from 0.001 to 600 s-1 – under rigid lateral confinement have been investigated, using an original experimental device especially developed for the purpose. The work is motivated by the need to explore the dynamic behavior of wood up to large strains close to 70%. Three experimental apparatus have been used to obtain the compressive responses: the quasi-static tests have been performed using a Sintech 20D test system, the compressive responses at intermediate strain rates have been obtained with an Instron VHS65/20 apparatus and the dynamic tests have been conducted using a Split Hopkinson Pressure Bars (SHPB) system. The strain rate sensitivity of wood is clearly visible on the crushing strength with an increase between 80 and 155% but also on the plastic like behavior. In addition, the entire responses exhibit an elastic-plastic like behavior whereas an elastic brittle behavior could be observed, in the previous Part A which was focused on the compression configuration without lateral confinement. Even if no significant effect of the rigid lateral confinement is observed on the apparent Young modulus and the crushing strength values for both species, the wood energy absorption capability is better when longitudinal failure mechanisms are restricted thanks to the rigid lateral confinement.

Impact of Thermal and Chemical Modifications on the Compression and Release Properties of Bambara Nut Starches in Directly Compressed Tablet Formulations

Chemical and physical modifications can be used to impart desired properties to native starches. The present study investigates the compaction, mechanical, and release properties of thermal and chemically modified starches from Bambara nuts in ibuprofen tablet formulations. The native starches extracted from Bambara nuts are modified to obtain the pregelatinized and carboxymethylated forms. Heckel, Kawakita, and Gurnham equations are used to analyze the compressional properties of the formulations. The crushing strength of the tablets are assessed while disintegration and dissolution times are used to evaluate the drug release properties of the tablets. Pregelatinized starch‐containing formulations exhibited faster onset and carboxymethylated starch had a higher amount of plastic deformation during compression than formulations incorporating the native starch. An increase in the particle size of Bambara starch had a significant effect on the densification of the starches during die filling, particle rearrangement, fragmentation propensity, and elastic/plastic deformation. The crushing strength and dissolution times of the tablets improves on starch modification. Tablets from the pregelatinized starch had longer disintegration time when compared with carboxymethylated and native Bambara starches. Formulations incorporating carboxymethylated starch had the shortest disintegration time, longest dissolution, and highest crushing strength values. The compressional, mechanical, and release properties of directly compressed ibuprofen tablet formulations are improved with the incorporation of the modified starches. Carboxymethylation and pregelatinization may be used to develop native starches as pharmaceutical excipients in specific formulations.

Addition impact of nano-carbon black on the performance of MgO.CaO compounds

In the present work, the influence of adding nano-carbon black (0, 0.5, 1, 1.5, 2, 2.5 and 3wt%) on the performance of MgO-CaO composites is discussed. Physical (bulk density, apparent porosity, and hydration resistance), mechanical (cold crushing strength), and thermo-chemical (corrosion resistance) properties of the specimens were evaluated. After formulation and shaping, all compositions were tempered at 250°C for 12h. Results indicated that by replacing nano-carbon black (up to 2wt%) in the MgO-CaO compositions, cold crushing strength values increased and then decreased (from 2.5 to 3wt%). Also, the use of nano-carbon black increased the hydration and corrosion resistance of the specimen due to (і) covering surfaces of the MgO and CaO grains (іі) creating a dense matrix and reducing porosities, and (ііі) formation of high hydration and corrosion resistance phase such as in-situ carbide phase (Al4C3) at operating temperature (1650°C). Generally, results showed that the use of carbon black nanoparticles (even in a small quantity) has a significant effect on the improvement of properties in MgO-CaO composites.

Promising Impregnated Mn-based Oxygen Carriers for Chemical Looping Combustion of Gaseous Fuels

Promising impregnated oxygen carriers, based on copper and iron, have been previously developed for CLC with gaseous fuels (CH4, syngas, LHC). Recently, because of its low cost and environmental compatibility, Mn-based oxygen carriers are now being considered as an attractive option for chemical-looping combustion (CLC) applications. In this work, a screening of different commercial supports in fluidizable particle size for impregnated Mn-based materials has been carried out. Different oxygen carriers have been prepared by incipient impregnation on ZrO2, and CaAl2O4, and evaluated with respect to their mechanical resistance, fuel gas reactivity and fluidization properties such as agglomeration and attrition rate. In a first step, particles showing high enough crushing strength values were selected for the reactivity investigation. The redox reactivity was evaluated through TGA experiments at suitable temperatures for the CLC process (i.e. 850-950°C) using H2, CO and CH4. Multi cycle redox analysis and full physical and chemical characterization was also performed. In a second step, materials with high enough reactivity were prepared for fluidized bed evaluation. A batch fluidized bed installation with continuous gaseous fuel feed was used to analyze the product gas distribution during reduction and oxidation reactions at different operation temperatures, and agglomeration and attrition behavior of the selected materials. Results showed that an oxygen carrier impregnated using ZrO2 as support, had high enough reactivity and low attrition rate. Therefore, this material can be selected as a candidate for the development of CLC with syngas with promising results.

Effects of Different Lightweight Functional Fillers for Use in Cementitious Composites

The effects of different lightweight functional fillers on the properties of cement-based composites are investigated in this study. The fillers include fly ash cenospheres (FACs) and glass micro-spheres (GMS15 and GMS38) in various proportions. The developed composites were tested for compressive, flexural and tensile strengths at 10 and 28-day ages. The results indicated that both FACs and GMS38 are excellent candidates for producing strong lightweight composites. However, incorporation of GMS15 resulted in much lower specific strength values (only up to 13.64 kPa/kg m3) due to its thinner shell thickness and lower isostatic crushing strength value (2.07 MPa). Microstructural analyses further revealed that GMS38 and GMS15 were better suited for thermal insulating applications. However, higher weight fraction of the fillers in composites leads to increased porosity which might be detrimental to their strength development.

Titanium substituted manganese-ferrite as an oxygen carrier with permanent magnetic properties for chemical looping combustion of solid fuels

Mixed oxides of Mn-Fe have been identified as suitable materials for Chemical Looping Combustion (CLC) with solid fuels both via in-situ Gasification Chemical Looping Combustion (iG-CLC) and Chemical Looping with Oxygen Uncoupling (CLOU) processes. These materials show the property of react with gaseous fuels as well as release oxygen under given conditions, while cheap metals are used. In addition, these materials can show magnetic properties that can be used for an easy separation from ash in CLC with solid fuels. Thus, losses of oxygen carrier material in the ash drain stream would be reduced. Different cations have been proposed for improving the magnetic properties of manganese ferrites, including Ti4+. In this context, the present work accomplishes a screening of (MnxFe1−x)2O3 doped with 7wt.% TiO2, with x ranging from 0 to 1. The influence of Mn:Fe ratio on their physical and chemical properties was evaluated. In general, particles with high crushing strength values (>4N) were obtained, and magnetic characteristics were highlighted when x⩽0.66. The oxygen uncoupling capability depended on the Mn:Fe ratio and the oxidation conditions, i.e. temperature and oxygen partial pressure. Broader oxidation conditions to take advantage of the oxygen uncoupling capability were found for materials with low Mn content. On contrary, the reactivity with fuel gases (CH4, H2 and CO) increased with the Mn content. Thus, oxygen carriers with Mn/(Mn+Fe) molar ratio in the 0.5–0.9 interval showed interesting properties at suitable temperatures for the iG-CLC and CLOU processes (i.e. 850–980°C). The material with Mn/(Mn+Fe)=0.55 was preferred considering a trade-off between reactivity and magnetic properties.

Complex ceramic architectures by directed assembly of ‘responsive’ particles

Surface functionalization of alumina powders with a responsive surfactant (BCS) leads to particles that react to a chemical switch. These ‘responsive’ building blocks are capable of assembling into macroscopic and complex ceramic structures. The aggregation follows a bottom up approach and can be easily controlled. The directed assembly of concentrated suspensions leads to highly dense (∼99%) ceramic components with average 4-point bending strength of ∼200MPa. On the other hand, the emulsification of suspensions with concentrations from 7 to 43vol% and 50vol% decane results in emulsions with different properties (stability, droplet size and distribution). The oil droplets provide a soft template confining the alumina particles in the continuous phase and at the oil/water interfaces. Aggregation of these emulsions followed by drying and sintering leads to macroporous (pore sizes ranging from 30 to 4μm) alumina structures with complex shapes and a wide range of microstructures, from closed cell structures to highly interconnected foams with total porosities up to 83%. Alumina scaffolds with ∼55% porosity can reach crushing strength values above 300MPa in compression and ∼50MPa in 4-point bending.

Lubricating Properties of Co-processed Coconut Oil in Paracetamol Tablets Formulation

Objective: Lubricants are additives which reduce friction and so essential components of drug formulation. This piece of work was initiated to evaluate coconut oil as a co-processed lubricant in the formulation and compression of paracetamol tablets in comparison with magnesium stearate-talc as standard lubricant. Methods: Various concentrations 0.5, 1.5, 2.0 and 2.5% w/w lubricant mixtures of magnesium stearate-talc (MT), coconut magnesium stearate-talc (CMT), magnesium stearate (M), coconut oil alone (C) respectively; and without lubricant (None) which served as control were thoroughly mixed with granules (200 mg) prepared from the basic formula for paracetamol tablets which contained 85% w/w, 5% w/w and 10% w/w of paracetamol powder, corn starch and lactose respectively. The mechanical properties of tablets produced were evaluated using crushing strength, friability and crushing strength -friability ratio while the release properties of tablets were evaluated using disintegration and dissolution tests. Results: Granules lubricated with coconut oil co-processed with magnesium stearate had excellent flow. The crushing strength obtained for all the paracetamol tablets had acceptable values ranging from 4.82 to 6.85 kgf except for tablets lubricated with coconut oil alone. Generally, as the crushing strength values increased the friability decreased. Friability values for all the tablets generally decreased with increasing tablet lubricant concentrations of 2.0% w/w and 2.5% w/w though falling within range considered for conventional tablets. The disintegration time increased with increase in lubricant concentration as all the tablets had acceptable values. Tablets lubricated with coconut oil mixed with magnesium stearate-talc showed the highest CSFR/DT ratio. As the concentration of lubricant increased, there was a general decrease in the rate and extent of the drug release from the formulation. Conclusion: Coconut oil is an effective lubricant which can be processed with magnesium stearate and talc for an effective lubrication of granules before compression into pharmaceutical tablets.

Characterisation of a novel, multifunctional, co-processed excipient and its effect on release profile of paracetamol from tablets prepared by direct compression

ObjectiveTo characterise a novel multifunctional pharmaceutical excipient and investigate its effect on paracetamol release from tablets prepared by direct compression. MethodsThe excipient was prepared by co-processing gelatinized maize starch with sodium carboxymethyl cellulose and microcrystalline cellulose in a ratio of 2:1:1, dried and pulverized into powder. The excipient formulated was characterized using Fourier transform infrared spectroscopy and differential scanning calorimetry. The excipient was used to prepare batches of tablets by direct compression with drug-excipient ratios of 1:1, 1:2, 1:3 and 1:4. Parameters evaluated on tablets include crushing strength, friability and in vitro dissolution studies. ResultsDifferential scanning calorimetry analysis revealed a crystalline excipient while Fourier transform infrared spectroscopy showed no interaction between the excipient and paracetamol. Tablets from all the batches gave average crushing strength values between 3.47 and 4.88 kp. The 1:1 and 1:2 tablet batches were comparable to each other while 1:3 and 1:4 were also comparable to one another in their dissolution profiles. The dissolution parameters of the 1:4 batch was faster with – m∞ (90.5%), t50% (3.5 min), t70% (11.6 min) while that of ratio 1:1 was the least with – m∞ (48.6%), m5min (23.8%). Their release kinetics followed a Korsmeyer–Peppas model with a super case-II transport mechanism. ConclusionsThe drug-excipient ratios of 1:3 and 1:4 gave pharmaceutically acceptable tablets that met the British Pharmacopoeia specifications. The t50% value of the 1:4 batch of tablets may find its usefulness in formulating drugs for which a fast onset of action is desired.