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Comparison of Disintegrant-addition Methods on the Compounding of Orodispersible Tablets

Mahesparan VA, Bin Abd Razak FS, Ming LC, Uddin AH, Sarker MZI, Bin LK

Int J Pharm Compd, 2020 3 21;24(2):148-155.
PMID: 32196477

Orodispersible tablets disintegrate rapidly (within 3 minutes) in the oral cavity and release the medicament before swallowing. The mode of disintegrant addition might affect the properties of orodispersible tablets. The objective of this study was to formulate and evaluate orodispersible tablets by studying different modes of disintegration addition with varying concentrations of disintegrants. The wet granulation method was used to produce the orodispersible tablets. Two methods of disintegration addition were compared (i.e., intragranular, extragranular). Three disintegrants (i.e., cornstarch, sodium starch glycolate, crospovidone) were used at three levels (5%, 10%, and 15%) in the study. The formulations were tested for the powder flowability (angle of repose) and characterized physically (hardness, weight, thickness, friability, disintegration time). The mangosteen pericarp extract was used as a model active pharmaceutical ingredient to be incorporated into the optimum formulation. It was observed that the extragranular method produced granules with better flowability compared to that of the intragranular method. Crospovidone was found as the most efficient disintegrant among the three. The optimum formulation selected was one with the highest concentration of crospovidone (15%), which showed the fastest disintegration time. The mode of disintegrant addition into the orodispersible tablets formulation was found to show a marked difference in the disintegration, as well as other physical characteristics of the orodispersible tablets where the extragranular mode of addition showed better property, which caused the orodispersible tablets to disintegrate the fastest.

Matched MeSH terms: Hardness
Fulltext The Development of Expanded Snack Product Made from Pumpkin Flour-Corn Grits: Effect of Extrusion Conditions and Formulations on Physical Characteristics and Microstructure

Nor NM, Carr A, Hardacre A, Brennan CS

Foods, 2013 May 14;2(2):160-169.
PMID: 28239106 DOI: 10.3390/foods2020160

Pumpkin products confer natural sweetness, desirable flavours and β-carotene, a vitamin A precursor when added as ingredients to extruded snacks. Therefore, a potential use for dried pumpkin flour is as an ingredient in ready-to-eat (RTE) snack foods. Growth in this market has driven food manufacturers to produce a variety of new high value snack foods incorporating diverse ingredients to enhance the appearance and nutritional properties of these foods. Ready-to-eat snacks were made by extruding corn grits with 5%, 10%, 15% and 20% of pumpkin flour. Snacks made from 100% corn grits were used as control products for this work. The effect of formulation and screw speeds of 250 rpm and 350 rpm on torque and specific mechanical energy (SME, kWh/kg), physical characteristics (expansion ratio, bulk density, true density and hardness) and the microstructure of the snacks were studied. Increasing the screw speed resulted in a decrease of torque for all formulations. When pumpkin flour was added the specific mechanical energy (SME) decreased by approximately 45%. Increasing the percentage of pumpkin flour at the higher screw speed resulted in a harder texture for the extruded products. X-ray tomography of pumpkin flour-corn grit snacks showed that increased levels of pumpkin flour decreased both the bubble area and bubble size. However, no significant differences (p > 0.05) in bubble wall thickness were measured. By understanding the conditions during extrusion, desirable nutritional characteristics can be incorporated while maximizing expansion to make a product with low bulk density, a fine bubble structure and acceptable organoleptic properties.

Matched MeSH terms: Hardness
Surface characterization and corrosion behavior of calcium phosphate-base composite layer on titanium and its alloys via plasma electrolytic oxidation: A review paper

Rafieerad AR, Ashra MR, Mahmoodian R, Bushroa AR

Mater Sci Eng C Mater Biol Appl, 2015 Dec 1;57:397-413.
PMID: 26354281 DOI: 10.1016/j.msec.2015.07.058

In recent years, calcium phosphate-base composites, such as hydroxyapatite (HA) and carbonate apatite (CA) have been considered desirable and biocompatible coating layers in clinical and biomedical applications such as implants because of the high resistance of the composites. This review focuses on the effects of voltage, time and electrolytes on a calcium phosphate-base composite layer in case of pure titanium and other biomedical grade titanium alloys via the plasma electrolytic oxidation (PEO) method. Remarkably, these parameters changed the structure, morphology, pH, thickness and crystallinity of the obtained coating for various engineering and biomedical applications. Hence, the structured layer caused improvement of the biocompatibility, corrosion resistance and assignment of extra benefits for Osseo integration. The fabricated layer with a thickness range of 10 to 20 μm was evaluated for physical, chemical, mechanical and tribological characteristics via XRD, FESEM, EDS, EIS and corrosion analysis respectively, to determine the effects of the applied parameters and various electrolytes on morphology and phase transition. Moreover, it was observed that during PEO, the concentration of calcium, phosphor and titanium shifts upward, which leads to an enhanced bioactivity by altering the thickness. The results confirm that the crystallinity, thickness and contents of composite layer can be changed by applying thermal treatments. The corrosion behavior was investigated via the potentiodynamic polarization test in a body-simulated environment. Here, the optimum corrosion resistance was obtained for the coating process condition at 500 V for 15 min in Ringer solution. This review has been summarized, aiming at the further development of PEO by producing more adequate titanium-base implants along with desired mechanical and biomedical features.

Matched MeSH terms: Hardness
Fulltext Effect of the Roasting Conditions on the Physicochemical, Quality and Sensory Attributes of Coffee-Like Powder and Brew from Defatted Palm Date Seeds

Fikry M, Yusof YA, Al-Awaadh AM, Rahman RA, Chin NL, Mousa E, et al.

Foods, 2019 Feb 06;8(2).
PMID: 30736332 DOI: 10.3390/foods8020061

Developing a bioactive brew is a novel track for revalorization of palm date byproducts. The effect of roasting temperature (160, 180 and 200 °C ) and roasting time (10, 20 and 30 min) on the hardness of the roasted date seeds, moisture content of the defatted roasted date seed powder (DRDSP), bulk density of the DRDSP, color parameters of DRDSP, quality attributes (extraction yield, pH and browning index), the chemical properties (antioxidants and total phenolic content) and the sensory attributes (color, aroma, taste and overall preference) of the brew prepared from DRDSP was studied. The physicochemical, quality, and sensory attributes were found to be significantly influenced by the roasting temperature and time. Additionally, the models proposed could satisfactorily describe the changes in the different properties during the roasting process. The optimum conditions of the roasting process obtained using the superimposed contour plot were 199.9 °C and 21.5 min. In the longer term, the results of this study would be beneficial for the manufacturers of the date seeds powder and brew.

Matched MeSH terms: Hardness
High mechanical strength and broad optical absorption in underexplored group IV nitride chalcogenides

Chang YHR

Chem Commun (Camb), 2020 Sep 17;56(74):10962-10965.
PMID: 32789397 DOI: 10.1039/d0cc04123h

While lab-scale synthesis of trigonal-Zr2N2S, hexagonal-Zr2N2S and hexagonal-Zr2N2Se has been reported, meaningful data on the photophysical properties of IV-nitride chalcogenides in general are scarcely available. The first-principles calculations and genetic algorithm modeling in our work reveal the existence of remarkably stable, indirect gap trigonal-Zr2N2Se and trigonal-Hf2N2Se phases, which progress to direct gap, monoclinic materials in monolayer form. These structures display the desired optoelectronic properties, such as exceptionally high visible-UV absorption spectra (105-106 cm-1) and exciton binding energy below 0.02 eV. Strong hybridization between the Zr-d, N-p and Se-p orbitals is accounted for by the polysilicon comparable Vickers hardness (10.64-12.77 GPa), while retaining ductile nature.

Matched MeSH terms: Hardness
Fulltext Microcellular rubber: a study on reclaimed natural rubber (NR) latex gloves/Standard Malaysian Rubber (SMR) 20 blends

Wan, Ngeow Yen, Chin, Khaw Pei, Che Su Mt. Saad

Pertanika Journal of Science & Technology, 2011;19(1):171-176.
MyJurnal

Reclaimed rubber from rejected natural rubber (NR) latex gloves (r-NRG) was evaluated as partial
replacement for Standard Malaysian Rubber (SMR) 20 in producing microcellular rubber. In the study, the amount of reclaimed rubber varied from 20 pphr to 95 pphr for the purpose of cost reduction, environmental interest and as processing aids in reducing internal porosity, swells and to minimize shrinkage and air-trapped problems in producing microcellular rubber. A typical formulation in making microcellular rubber slab was developed and two-roll mill was used for compounding. The cure characteristics and mechanical properties, such as density, hardness, tensile strength, and elongation at break, were evaluated. Scorch time and cure rate index performed marginal decreased with increasing of r-NRG content. 95 pphr r-NRG blends showed a consequential drop in hardness. Both tensile properties and elongation at break decreased as the r-NRG content was increased.

Matched MeSH terms: Hardness
Fulltext Effect of MgO Addition on the Mechanical and Dynamic Properties of Zirconia Toughened Alumina (ZTA) Ceramics

Arab A, Sktani ZDI, Zhou Q, Ahmad ZA, Chen P

Materials (Basel), 2019 Jul 31;12(15).
PMID: 31370216 DOI: 10.3390/ma12152440

Zirconia toughened alumina (ZTA) is a promising advanced ceramic material for a wide range of applications that are subjected to dynamic loading. Therefore, the investigation of dynamic compressive strength, fracture toughness and hardness is essential for ZTA ceramics. However, the relationship between these mechanical properties in ZTA has not yet been established. An example of this relationship is demonstrated using ZTA samples added with MgO prepared through conventional sintering. The microstructure and mechanical properties of ZTA composites were characterized. The hardness of ZTA composites increased for ≤0.7 wt.% MgO due to the pinning effect of MgO and decrease of the porosity in the microstructure. Oppositely, the fracture toughness of ZTA composites continuously decreased due to the size reduction of Al2O3 grains. This is the main reason of deteriorate of dynamic compressive strength more than 0.2 wt.% of MgO addition. Therefore, the SHPB test shows the improvement of the dynamic compressive strength only up to a tiny amount (0.2 wt.% of MgO addition) into ZTA ceramics.

Matched MeSH terms: Hardness
Methods of assessment of early dentine erosion: a review

Habib M, Chew HP

J Pak Med Assoc, 2019 Oct;69(10):1509-1513.
PMID: 31622307

Dentine erosion is an increasingly recognised problem, especially in aging population, and various methods have been utilised for its assessment. This narrative review was planned to summarise the methods for the assessment of the early stages of dentine erosion. Relevant original articles published in the English language from 2013 to 2017 were reviewed. Laboratory techniques and methods with in vivo potential were separately studied. It is evident that the assessment of early dentine erosion is complex and requires a combination of methods. For clinical evaluation, chemical analysis and optical methods show great potential but are in need of more validation.

Matched MeSH terms: Hardness Tests
Fulltext Effect of roasting conditions on hardness, moisture content and colour of pistachio kernels

Shakerardekani, A., Karim, R, Mohd Ghazali, H, Chin, N.L.

International Food Research Journal, 2011;18(2):723-729.
MyJurnal

Roasting of whole-kernels is an important step in the production of pistachio paste. The effect of hot air roasting temperatures (90-190°C) and times (5-65 min) on the hardness, moisture content and colour attributes (‘L’, ‘a’ and ‘b’ values and yellowness index) of both whole-kernel and ground-state were investigated using response surface methodology (RSM). Increases in roasting temperature and time caused a decrease in all the responses except for ‘a’ value of ground-state. The interaction and quadratic models sufficiently described the changes in the hardness and colour values, respectively. The result of RSM analysis showed that hardness and colour attributes (‘L’ and ‘b’ values, yellowness index) of kernels and ‘a’ value of ground-state could be used to monitor the roasting quality of whole-kernels. This study showed that the recommended range of roasting temperature and time of whole-kernel for the production of pistachio paste were 130-140°C and 30-40 min, respectively.

Matched MeSH terms: Hardness
Effect of electron beam irradiation on natural rubber/linear low density polyethylene blends with m-phenylenebismaleimide

Nor Hayati Muhammad, Ibrahim Abdullah, Dahlan Mohd

Sains Malaysiana, 2011;40:1179-1186.

The effects of HVA-2 on radiation-induced cross-linkings in 60/40 natural rubber/ linear low density polyethylene (NR/LLDPE) blends was studied. NR/LLDPE was irradiated by using a 3.0 MeV electron beam machine with doses ranging from 0 to 250 kGy. Results showed that under the irradiation employed, the blends NR/LLDPE were cross-linked by the electron beam irradiation. The presence of HVA-2 in the blends caused the optimum dose to decrease and the blends to exhibit higher tensile properties. Further, within the dose range studied, the degradation caused by electron beam irradiation was found to be minimal. The optimized processing conditions were 120oC, 50 rpm rotor speed and 13 min processing time. The gel content, tensile strength, elongation at break, hardness and impact test studies were used to follow the irradiation-induced cross-linkings in the blend. For blends of 60/40 NR/LLDPE with 2.0 phr HVA-2, the optimum tensile strength and dose, were 19 MPa and 100 kGy, respectively. Blends of 60/40 NR/LLDPE without HVA-2, the optimum tensile strength and dose were 17.2 MPa and 200 kGy, respectively.

Matched MeSH terms: Hardness
Physicochemical and sensorial evaluation of biscuit and muffin incorporated with young corn powder

Anis Jauharah M, Wan Rosli W, Daniel Robert S

Sains Malaysiana, 2014;43:45-52.

Various types of natural fibre-rich ingredients are added into bakery-based products to improve their fibre content for health promotional purposes. However, most of these products are frequently added with imported dietary fibre ingredients. The aim of this study was to develop bakery products incorporated with young corn powder (YCP) and to evaluate the effects on physicochemical properties and sensory acceptabilities. Dried young corn was used to substitute wheat flour in biscuit and muffin formulations at different levels (0, 10, 20 and 30%). The effects of YCP incorporation on proximate compositions, physical characteristics, texture profile and sensory evaluation of both bakery products were investigated. The present results showed that YCP had significantly increased protein and total dietary fibre contents of both biscuit and muffin. Hardness attribute of both products increased in line with the level of YCP addition. Interestingly, biscuit and muffin containing 10% YCP received better score than the control and other formulations for most of the sensorial attributes judged. In conclusion, YCP can be potentially be used as an alternative functional ingredient for partial replacement of wheat flour in formulating biscuit and muffin because of its ability to improve the nutritional quality without jeopardizing sensorial palatability.

Matched MeSH terms: Hardness
Fulltext Co-Blend Application Mode of Bulk Fill Composite Resin

Al-Nabulsi M, Daud A, Yiu C, Omar H, Sauro S, Fawzy A, et al.

Materials (Basel), 2019 Aug 07;12(16).
PMID: 31394743 DOI: 10.3390/ma12162504

Objective: To evaluate the effect of a new application method of bulk-fill flowable composite resin material on bond-strength, nanoleakage, and mechanical properties of dentine bonding agents.
MATERIALS AND METHODS: Sound extracted human molars were randomly divided into: manufacturer's instructions (MI), manual blend 2 mm (MB2), and manual blend 4 mm (MB4). Occlusal enamel was removed and flattened, dentin surfaces were bonded by Prime & Bond universal (Dentsply and Optibond FL, Kerr). For the MI group, adhesives were applied following the manufacturer's instructions then light-cured. For MB groups, SDR flow+ bulk-fill flowable composite resin was applied in 2- or 4-mm increment then manually rubbed by a micro brush for 15 s with uncured dentine bonding agents and the mixture was light-cured. Composite buildup was fabricated incrementally using Ceram.X One, Dentsply nanohybrid composite resin restorative material. After 24-h water storage, the teeth were sectioned to obtain beams of about 0.8 mm2 for 24-h and thermocycled micro-tensile bond strength at 0.5 mm/min crosshead speed. Degree of conversion was evaluated with micro-Raman spectroscopy. Contraction gaps at 24 h after polymerization were evaluated and atomic force microscopy (AFM) nano-indentation processes were undertaken for measuring the hardness across the interface. Depth of resin penetration was studied using a scanning electron microscope (SEM). Bond strength data was expressed using two-way ANOVA followed by Tukey's test. Nanoindentation hardness was separately analyzed using one-way ANOVA.
RESULTS: Factors "storage F = 6.3" and "application F = 30.11" significantly affected the bond strength to dentine. For Optibond FL, no significant difference in nanoleakage was found in MI/MB4 groups between baseline and aged specimens; significant difference in nanoleakage score was observed in MB2 groups. Confocal microscopy analysis showed MB2 Optibond FL and Prime & Bond universal specimens diffusing within the dentine. Contraction gap was significantly reduced in MB2 specimens in both adhesive systems. Degree of conversion (DC) of the MB2 specimens were numerically more compared to MS1 in both adhesive systems.
CONCLUSION: Present study suggests that the new co-blend technique might have a positive effect on bond strengths of etch-and-rinse adhesives to dentine.

Matched MeSH terms: Hardness
Fulltext Effect of home bleaching agents on the hardness and surface roughness of resin composites

Farahiyah Mohamad Taib, Zuryati Ab Ghani, Dasmawati Mohamad

Archives of Orofacial Sciences, 2013;8(1):34-40.
MyJurnal

Ten percent carbamide peroxide is an effective, safe home bleaching agent. Higher concentrations
are more effective, but there are mixed reports on their hardness and surface roughness effects on resin composites. To evaluate the effect of home bleaching agents; Opalescence Now 10% carbamide peroxide (Ultradent Products, USA) and Perfect Bleach 17% carbamide peroxide (Voco,
Germany) on the surface hardness of microhybrid resin composites; Filtek Z250 (3M ESPE, USA) and Point 4 (Kerr, USA) and their surface roughness of selected treatment. Thirty specimens were prepared using acrylic moulds (4mm diameter x2mm thick). N=5 controls placed in distilled water for 14 days.N=5 treated with Opalescence, and n=5 treated with Perfect Bleach for 2 hours every day for 14 days. Surface hardness was tested using Vickers hardness tester FV-7 (Future Tech Corp, Japan). Data analyzed with Mann-Whitney test with (P

Matched MeSH terms: Hardness
Mechanical properties of Bitumen Quenched dual phase steel

M.O.H. Amuda, T.A. Olaniyan, L.O. Osoba, E.T. Akinlabi

Sains Malaysiana, 2017;46:743-753.

The mechanical properties of Dual Phase Steel (DPS)-duplex structure-produced by quenching in pre-heated bitumen have been investigated. Medium carbon steels intercritically heated at different temperatures and holding times were quenched in hot bitumen. Optical and scanning electron microscopy characterisation of the duplex structure showed extensive network of fibrous martensite in a ferritic matrix with occasional presence of polygonal martensite. The duplex phase structure exhibited continuous yielding dynamics, improving the tensile and hardness values by about 42 and 35%, respectively, relative to the normalised structure. But, the elongation and impact values decreased by about 42 and 50%, respectively, when compared to the normalised structure. These values are similar to those obtained in duplex structure produced using conventional oil quenching. The tensile fractured surface showed transition between a predominantly cleavage mode in the lower annealing temperature to a mixed mode in the upper bound of the annealing temperature. These findings suggest that pre-heated bitumen can be exploited for the production of DPSs.

Matched MeSH terms: Hardness
Optimization of soy protein isolate, microbial transglutaminase and glucono-δ-lactone in gluten-free rice noodles

Ojukwu M, Ofoedu C, Seow EK, Easa AM

J Sci Food Agric, 2021 Jul;101(9):3732-3741.
PMID: 33301191 DOI: 10.1002/jsfa.11004

BACKGROUND: Rice flour does not contain gluten and lacks cohesion and extensibility, which is responsible for the poor texture of rice noodles. Different technologies have been used to mitigate this challenge, including hydrothermal treatments of rice flour, direct addition of protein in noodles, use of additives such as hydrocolloids and alginates, and microbial transglutaminase (MTG). Recently, the inclusion of soy protein isolate (SPI), MTG, and glucono-δ-lactone (GDL) in the rice noodles system yielded rice noodles with improved texture and more compact microstructure, hence the need to optimize the addition of SPI, MTG, and GDL to make quality rice noodles.
RESULTS: Numerical optimization showed that rice noodles prepared with SPI, 68.32 (g kg-1 of rice flour), MTG, 5.06 (g kg-1 of rice flour) and GDL, 5.0 (g kg-1 of rice flour) gave the best response variables; hardness (53.19 N), springiness (0.76), chewiness (20.28 J), tensile strength (60.35 kPa), and cooking time (5.15 min). The pH, sensory, and microstructure results showed that the optimized rice noodles had a more compact microstructure with fewer hollows, optimum pH for MTG action, and overall sensory panelists also showed the highest preference for the optimized formulation, compared to other samples selected from the numerical optimization and desirability tests.
CONCLUSION: Optimization of the levels of SPI, MTG, and GDL yielded quality noodles with improved textural, mechanical, sensory, and microstructural properties. This was partly due to the favourable pH value of the optimized noodles that provided the most suitable conditions for MTG crosslinking and balanced electrostatic interaction of proteins. © 2020 Society of Chemical Industry.

Matched MeSH terms: Hardness
Effects of honey types and heating treatment on the textural, thermal, microstructural, and chemical properties of glutinous rice flour gels

Seow EK, Tan TC, Lee LK, Easa AM

J Texture Stud, 2020 12;51(6):909-916.
PMID: 32537814 DOI: 10.1111/jtxs.12544

Hardening issue in starch-based products that arises during storage, is ascribed to the long-term starch retrogradation which involves the recrystallisation of amylopectin. Present study aimed to delay storage hardening with the addition of high diastase honey bee honey (HBH) and low diastase kelulut bee honey (KBH) into glutinous rice flour (GRF) gels. As compared to KBH, retardation of texture deterioration by HBH was more prominent as evidenced by the significantly (p

Matched MeSH terms: Hardness
Fulltext The effects of egg white powder addition with tapioca and sago flours on physicochemical and sensory properties of duck sausage

Muthia, D., Huda, N., Ismail, N., Easa, A.M.

International Food Research Journal, 2012;19(4):1415-1421.
MyJurnal

The objective of this study was to evaluate the effects of using tapioca and sago flours with or without egg white powder (EWP) on the physicochemical and sensory properties of duck sausages. There was significant increase (P0.05) in hardness and cohesiveness attributes among all the samples examined but significant differences (P

Matched MeSH terms: Hardness
Fulltext Effect of duck feet collagen addition on physicochemical properties of surimi

Huda, N., Seow, E.K., Normawati, M. N., Nik Aisyah, N. M., Fazilah, A., Easa, A.M.

International Food Research Journal, 2013;20(2):537-544.
MyJurnal

Duck feet collagen was added to threadfin bream and sardine surimi to study its effect on physicochemical properties such as folding test, gel strength, cook loss, water holding capacity, expressible moisture, texture profile analysis and colour measurement. As compared to commercial fish scale collagen and cow collagen, the addition of duck feet collagen resulted in a significant improvement in the quality of the sardine surimi. Duck feet collagen was able to improve the folding test score of sardine surimi from 3.00 to 5.00; gel strength was increased from 275.70 g.mm to 2682.70 g.mm and hardness of gel was increased from 1.12kg to 6.00kg. Addition of duck feet collagen improved the gel strength of threadfin bream surimi from 1696.70 g.mm to 5579.40 g.mm and hardness of gel was increased from 4.55kg to 10.32kg. Colour of threadfin bream and sardine surimi also improve with the addition of duck feet collagen. The lightness was increased from 66.47 to 66.89 (threadfin bream) and from 62.32 to 63.60 for sardine. The results suggest that duck feet collagen has potential as an alternative source of protein additive for the improvement of the physicochemical properties of low grade surimi.

Matched MeSH terms: Hardness
Fulltext Development and evaluation of Ketoprofen sustained release matrix tablet using Hibiscus rosa-sinensis leaves mucilage

Kaleemullah M, Jiyauddin K, Thiban E, Rasha S, Al-Dhalli S, Budiasih S, et al.

Saudi Pharm J, 2017 Jul;25(5):770-779.
PMID: 28725150 DOI: 10.1016/j.jsps.2016.10.006

Currently, the use of natural gums and mucilage is of increasing importance in pharmaceutical formulations as valuable drug excipient. Natural plant-based materials are economic, free of side effects, biocompatible and biodegradable. Therefore, Ketoprofen matrix tablets were formulated by employing Hibiscus rosa-sinensis leaves mucilage as natural polymer and HPMC (K100M) as a synthetic polymer to sustain the drug release from matrix system. Direct compression method was used to develop sustained released matrix tablets. The formulated matrix tablets were evaluated in terms of physical appearance, weight variation, thickness, diameter, hardness, friability and in vitro drug release. The difference between the natural and synthetic polymers was investigated concurrently. Matrix tablets developed from each formulation passed all standard physical evaluation tests. The dissolution studies of formulated tablets revealed sustained drug release up to 24 h compared to the reference drug Apo Keto® SR tablets. The dissolution data later were fitted into kinetic models such as zero order equation, first order equation, Higuchi equation, Hixson Crowell equation and Korsmeyer-Peppas equation to study the release of drugs from each formulation. The best formulations were selected based on the similarity factor (f2) value of 50% and more. Through the research, it is found that by increasing the polymers concentration, the rate of drug release decreased for both natural and synthetic polymers. The best formulation was found to be F3 which contained 40% Hibiscus rosa-sinensis mucilage polymer and showed comparable dissolution profile to the reference drug with f2 value of 78.03%. The release kinetics of this formulation has shown to follow non-Fickian type which involved both diffusion and erosion mechanism. Additionally, the statistical results indicated that there was no significant difference (p > 0.05) between the F3 and reference drug in terms of MDT and T50% with p-values of 1.00 and 0.995 respectively.

Matched MeSH terms: Hardness
Fulltext EIS and DFT investigations on corrosion inhibition of Imines containing Mono- and Diisatin Moieties

Aliyin Abdul Ghani, Hadariah Bahron, Mohamad Kamal Harun, Karimah Kassim, El Hassane Anouar

Pertanika Journal of Science & Technology, 2017;25(103):297-308.
MyJurnal

Two imines of different molecular sizes namely 3-(phenylimino) indolin-2-one (PII) and 3,3- (1,4-phenylenebis (azan-1-yl-1-ylidene) diindolin-2-one (PDI) were investigated for their corrosion inhibition on mild steel in 1 M HCl solution using electrochemical impedance spectroscopy (EIS). The bigger molecule PDI containing double the amount of isatin moiety exhibited higher inhibition efficiency of 87.3% while PII that contained monoisatin moiety showed a lower inhibition efficiency of 74.8%. Both compounds had an increase in inhibition efficiencies percentage as concentrations increased. Density functional theory (DFT) was used to determine the correlation between the corrosion inhibition efficiency and electronic parameters. The DFT calculations indicated that the corrosion inhibition efficiency was mainly dependant on the frontier orbital energy gap and the chemical softness/hardness of the imines.

Matched MeSH terms: Hardness

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