Displaying publications 1 - 20 of 142 in total

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  1. Diclofenac release from eudragit-containing matrices and effects of thermal treatment
    Billa N, Yuen KH, Peh KK
    Drug Dev Ind Pharm, 1998 Jan;24(1):45-50.
    PMID: 15605596
    Ethyl acrylate-methyl methacrylate copolymer (Eudragit NE40D) was evaluated as matrix material for preparing controlled-release tablets of diclofenac sodium. Drug release could be modified in a predictable manner by varying the Eudragit NE40D content, but was pH dependent, being markedly reduced at lower pH. This could be attributed to the low solubility of the drug at these pH values. Thermal treatment of the tablets at 60 degrees C was also found to affect the rate of drug release, which was found to decrease with an increase in the treatment duration, but could be stabilized after 96 hr of treatment. This was also associated with a corresponding increase in the tablet tensile strength. However, treatment of the granules for 5 hr prior to compaction into tablets could shorten the stabilizing time of the drug release to 48 hr and that of the tensile strength to 24 hr. The effect of thermal treatment may be ascribed to better coalescence of the Eudragit particles to form a fine network, resulting in matrix of higher tortuosity and lower porosity.
    Matched MeSH terms: Excipients/chemistry*
  2. Gamma-scintigraphic study of the gastrointestinal transit and in vivo dissolution of a controlled release diclofenac sodium formulation in xanthan gum matrices
    Billa N, Yuen KH, Khader MA, Omar A
    Int J Pharm, 2000 May 15;201(1):109-20.
    PMID: 10867269
    A xanthan gum matrix controlled release tablet formulation containing diclofenac sodium was evaluated in vitro and was found to release the drug at a uniform rate. The gastrointestinal transit behaviour of the formulation as determined by gamma scintigraphy, using healthy male volunteers under fasted and fed conditions, indicated that gastric emptying was delayed with food intake. In contrast, the small intestinal transit remained practically unchanged under both food statuses. Therefore, the delay in caecal arrival observed in the fed state can be attributed to the delay in gastric emptying. Rate of diclofenac sodium absorption was generally higher in the fed state compared to the fasted state, however the total amount absorbed under both food statuses remained practically the same. The rate of in vivo dissolution of the drug in the fed state was faster compared to that in the fasted state. Thus, at the time of caecal arrival, in vivo dissolution was complete in the fed state, unlike in the fasted state, where almost 60% of the drug was delivered to the colon.
    Matched MeSH terms: Excipients
  3. Use of artificial neural networks to predict drug dissolution profiles and evaluation of network performance using similarity factor
    Peh KK, Lim CP, Quek SS, Khoh KH
    Pharm Res, 2000 Nov;17(11):1384-8.
    PMID: 11205731
    PURPOSE: To use artificial neural networks for predicting dissolution profiles of matrix-controlled release theophylline pellet preparation, and to evaluate the network performance by comparing the predicted dissolution profiles with those obtained from physical experiments using similarity factor.

    METHODS: The Multi-Layered Perceptron (MLP) neural network was used to predict the dissolution profiles of theophylline pellets containing different ratios of microcrystalline cellulose (MCC) and glyceryl monostearate (GMS). The concepts of leave-one-out as well as a time-point by time-point estimation basis were used to predict the rate of drug release for each matrix ratio. All the data were used for training, except for one set which was selected to compare with the predicted output. The closeness between the predicted and the reference dissolution profiles was investigated using similarity factor (f2).

    RESULTS: The f2 values were all above 60, indicating that the predicted dissolution profiles were closely similar to the dissolution profiles obtained from physical experiments.

    CONCLUSION: The MLP network could be used as a model for predicting the dissolution profiles of matrix-controlled release theophylline pellet preparation in product development.

    Matched MeSH terms: Excipients/chemistry
  4. Influence of Inlet Air Temperature and Feed Flow Rate on the Physical Properties of Spray-dried Mengkudu (Morinda citrifolia) Extract
    Mohamad Yusof Maskat, Lee LY
    Sains Malaysiana, 2004;33.
    Due to the increase in consumer interest, mengkudu (Morinda citrifolia) extract is being produced in several forms including dry powder. One of the methods that can be used to produce dry powder is spray drying. This study was done to determine the physical properties of powdered mengkudu extract produced by spray drying from different sections of the spray-dryer. Mengkudu extract at 50% (v/v) dilution was spray-dried using two levels of feed flow rate (350 mL/hr and 475 mL/hr) and inlet air temperature (170oC and 190oC). Spray dried mengkudu extract from the cyclone and colletion sections of the spray dryer was collected and analyzed for amount produced, moisture content and colour. No significant interaction between feed flow rate and inlet air temperature used was observed for all parameters measured. Inlet temperature used did not show any significant effect on amount of production. However, increasing the inlet air temperature from 170oC to 190oC did produce lower moisture content for samples from the cyclone but no significant difference for samples from the collection bottle, while lowering the degree of redness of samples from the collection bottle, while lowering the degree of brightness for samples from both cyclone and collection sections of the spray-dryer. Feed flow rate used did not produce any significant effect on all parameters measured.
    Matched MeSH terms: Excipients
  5. Comparison studies on the percolation thresholds of binary mixture tablets containing excipients of plastic/brittle and plastic/plastic deformation properties
    Amin MC, Fell JT
    Drug Dev Ind Pharm, 2004;30(9):937-45.
    PMID: 15554218
    Percolation theory has been used with great interest in understanding the design and characterization of dosage forms. In this study, work has been carried out to investigate the behavior of binary mixture tablets containing excipients of similar and different deformation properties. The binary mixture tablets were prepared by direct compression using lactose, polyvinyl chloride (PVC), Eudragit RS 100, and microcrystalline cellulose (MCC). The application of percolation theory on the relationships between compactibility, Pmax, or compression susceptibility (compressibility), gamma, and mixture compositions reveals the presence of percolation thresholds even for mixtures of similar deformation properties. The results showed that all mixture compositions exhibited at least one discreet change in the slope, which was referred to as the percolation threshold. The PVC/Eudragit RS100 mixture compositions showed significant percolation threshold at 80% (w/w) PVC loading. Two percolation thresholds were observed from a series of binary mixtures containing similar plastic deformation materials (PVC/MCC). The percolation thresholds were determined at 20% (w/w) and 80% (w/w) PVC loading. These are areas where one of the components percolates throughout the system and the properties of the tablets are expected to experience a sudden change. Experimental results, however, showed that total disruption of the tablet physical properties at the specified percolation thresholds can be observed for PVC/lactose mixtures at 20-30% (w/w) loading while only minor changes in the tablets' strength for PVC/MCC or PVC/Eudragit RS 100 mixtures were observed.
    Matched MeSH terms: Excipients/chemistry*
  6. Significance of lipid matrix aging on in vitro release and in vivo bioavailability
    Choy YW, Khan N, Yuen KH
    Int J Pharm, 2005 Aug 11;299(1-2):55-64.
    PMID: 15955645
    A polyglycolised glyceride carrier, Gelucire 50/13, was incorporated with paracetamol as a model drug, filled into hard gelatin capsules and stored at three different temperatures for various lengths of time. The resultant solidified matrix within the capsule was subjected to thermal analysis using differential scanning calorimetry (DSC) to ascertain its supramolecular structure. Polymorphic transformations towards more stable gelucire forms were observed upon aging the matrices, with samples stored at a temperature near the melting range of the lower temperature gelucire melting fraction showing the most profound changes. The increase in the rate of drug release from aged samples could be correlated to the alterations to the supramolecular structure of the gelucire. Accelerated drug release from aged samples could also be seen from in vivo studies using healthy human volunteers, although the extent of absorption was not affected. Therefore, even though the sustainability of release may be compromised by aging the gelucire matrices, the bioavailability of the incorporated drug is unlikely to be affected.
    Matched MeSH terms: Excipients/chemistry
  7. Formation of in vivo tissue engineered human hyaline cartilage in the shape of a trachea with internal support
    Ruszymah BH, Chua K, Latif MA, Hussein FN, Saim AB
    Int J Pediatr Otorhinolaryngol, 2005 Nov;69(11):1489-95.
    PMID: 15941595
    Treatment and management of congenital as well as post-traumatic trachea stenosis remains a challenge in pediatric surgery. The aim of this study was to reconstruct a trachea with human nasal septum chondrocytes by using the combination of biodegradable hydrogel and non-biodegradable high-density polyethylene (HDP) as the internal predetermined shape scaffold.
    Matched MeSH terms: Excipients
  8. Fulltext Determination of gold coating thickness measurement by using EDXRF
    Meor Yusoff, M.S., Masliana Muslimin, Fadlullah Jili Fursani
    Journal of Nuclear and Related Technologies, 2005;2005(2):57-62.
    MyJurnal
    The paper relates a study on the development of an analysis procedure for measuring the gold coating thickness using EDXRF technique. Gold coating thickness was measured by relating the counts under the Au Lα peak its thickness value. In order to get a reasonably accurate result, a calibration graph was plotted using five gold-coated reference standards of different thicknesses. The calibration graph shows a straight line for thin coating measurement until 0.9μm. Beyond this the relationship was not linear and this may be resulted from the selfabsorption effect. Quantitative analysis was also performed on two different samples of goldcoated jewelry and a phone connector. Result from the phone connector analysis seems to agree with the manufacturer’s gold coating value. From the analysis of gold-coated jewelry it had been able to differentiate the two articles as gold wash and gold electroplated.
    Matched MeSH terms: Excipients
  9. Use of microwave in processing of drug delivery systems
    Wong TW
    Curr Drug Deliv, 2008 Apr;5(2):77-84.
    PMID: 18393808
    Microwave has received a widespread application in pharmaceuticals and food processing, microbial sterilization, biomedical therapy, scientific and biomedical analysis, as well as, drug synthesis. This paper reviews the basis of application of microwave to prepare pharmaceutical dosage forms such as agglomerates, gel beads, microspheres, nanomatrix, solid dispersion, tablets and film coat. The microwave could induce drying, polymeric crosslinkages as well as drug-polymer interaction, and modify the structure of drug crystallites via its effects of heating and/or electromagnetic field on the dosage forms. The use of microwave opens a new approach to control the physicochemical properties and drug delivery profiles of pharmaceutical dosage forms without the need for excessive heat, lengthy process or toxic reactants. Alternatively, the microwave can be utilized to process excipients prior to their use in the formulation of drug delivery systems. The intended release characteristics of drugs in dosage forms can be met through modifying the physicochemical properties of excipients using the microwave.
    Matched MeSH terms: Excipients/chemistry
  10. Design of a 24-hour controlled porosity osmotic pump system containing PVP: formulation variables
    Yakubu R, Peh KK, Tan YT
    Drug Dev Ind Pharm, 2009 Dec;35(12):1430-8.
    PMID: 19929202 DOI: 10.3109/03639040902988566
    The purpose of this study was to design a 24-hour controlled porosity osmotic pump system that utilizes polyvinyl pyrrolidone (PVP) as an osmotic-suspending/release retarding agent of drugs.
    Matched MeSH terms: Excipients/chemistry*
  11. Fulltext Exploring the potential of a highly compressible microcrystalline cellulose as novel tabletting excipient in the compaction of extended-release coated pellets containing an extremely water-soluble model drug
    Zeeshan F, Peh KK, Tan YT
    AAPS PharmSciTech, 2009;10(3):850-7.
    PMID: 19554454 DOI: 10.1208/s12249-009-9278-2
    Compaction of controlled-release coated pellets into tablets is challenging because of the fusion of pellets and the rupturing of coated film. The difficulty in compaction intensifies with the use of extremely water-soluble drugs. Therefore, the present study was conducted to prepare and compact pellets containing pseudoephedrine hydrochloride as an extremely water-soluble model drug. The pellets were produced using an extrusion-spheronization technique. The drug-loaded pellets were coated to extend the drug release up to 12-h employing various polymers, and then they were compressed into tablets using microcrystalline cellulose Ceolus KG-801 as a novel tabletting excipient. The in vitro drug release studies of coated pellets and tablets were undertaken using the USP basket method in dissolution test apparatus I. The amount of drug released was analyzed at a wavelength of 215 nm. The combined coatings of hydroxypropyl methylcellulose and Kollicoat SR-30D yielded 12-h extended-release pellets with drug release independent of pH of dissolution medium following zero-order kinetics. The drug release from the tablets prepared using inert Celous KG-801 granules as tabletting excipient was found faster than that of coated pellets. However, a modification in drug release rate occurred with the incorporation of inert Ceolus KG-801 pellets. The drug dissolution profile from tablets containing 40% w/w each of coated pellets and inert granules along with 20% w/w inert pellets was found to be closely similar to that of coated pellets. Furthermore, the friability, tensile strength, and disintegration time of the tablets were within the USP specifications.
    Matched MeSH terms: Excipients
  12. Utilization of green banana flour as a functional ingredient in yellow noodle
    Saifullah, R., Abbas, F.M.A., Yeoh, S.Y., Azhar, M.E.
    International Food Research Journal, 2009;16(3):373-379.
    MyJurnal
    Banana pulp (BP) noodles prepared by partial substitution of wheat flour with green Cavendish banana pulp flour were assessed pH, color, tensile strength and elasticity, and in-vitro hydrolysis index (HI) and estimated glycemic index (GI). BP noodles had lower L* (darker) and b* values (less yellow) but higher tensile strength and elasticity modulus than control noodles. Following an in-vitro starch hydrolysis studies, it was found that GI of BP noodles was lower than control noodles. Partial substitution of green banana pulp into noodles may be useful for controlling starch hydrolysis of yellow noodles.
    Matched MeSH terms: Excipients
  13. Fulltext Functional and pasting properties of a tropical breadfruit (Artocarpus altilis) starch from Ile-Ife, Osun State, Nigeria
    Akanbi, T.O., Nazamid, S., Adebowale, A.A.
    International Food Research Journal, 2009;16(2):151-157.
    MyJurnal
    This study was carried out to determine the proximate, functional and pasting properties of breadfruit starch. Breadfruit starch was isolated from matured breadfruit (Artocarpus altilis) and was analyzed for its fuctional, proximate and pasting properties. The starch contains 10.83%, 0.53%, 0.39%, 22.52%, 77.48% and 1.77% moisture, crude protein, fat, amylose, amylopectin and ash contents respectively. The average particle size, pH, bulk density and dispersibility of the breadfruit starch were 18 μm, 6.5, 0.673 g/mls, and 40.67% respectively. The swelling power of the breadfruit starch increases with increase in temperature, but there was a rapid increase in the swelling power from 70 to 80 0C. The pasting temperature of the starch paste was 84.05 0C, setback and breakdown values were 40.08 and 7.92 RVU respectively. The peak viscosity value was 121.25 RVU while final viscosity value was 153.42 RVU. This study concluded that breadfruit starch has an array of functional, pasting and proximate properties that can facilitate its use in so many areas where the properties of other starches are acceptable.
    Matched MeSH terms: Excipients
  14. Fulltext Sensory descriptive analysis and consumer acceptability of original “kaya” and “kaya” partially substituted with inulin
    Phang, Y.L., Chan, H.K.
    International Food Research Journal, 2009;16(4):483-492.
    MyJurnal
    A study was done on the feasibility of inulin, a fructooligosaccharides with the health benefits of prebiotic, as partial sugar replacer in “kaya” by investigating the effects of different substitution levels (0%; control, 10%, 30% and 50%) on the sensory properties. The samples were investigated by 10 descriptive panelists for colour, sweetness, smoothness, firmness, adhesiveness and spreadability attributes before further evaluated by 100 consumers for acceptance levels. Consistent with the descriptive panel, the evaluation by the consumers showed formulated samples at 10% and 30% were comparable to the commercial “kaya” being no significant difference (p>0.05) found in acceptability scores. 50% substitution received lower acceptability scores and was significantly different (p
    Matched MeSH terms: Excipients
  15. Interfacial elastic relaxation during the ejection of bi-layered tablets
    Anuar MS, Briscoe BJ
    Int J Pharm, 2010 Mar 15;387(1-2):42-7.
    PMID: 19963050 DOI: 10.1016/j.ijpharm.2009.11.031
    The predilection of a bi-layered tablet to fail in the interface region after its initial formation in the compaction process reduces its practicality as a choice for controlled release solid drug delivery system. Hence, a fundamental appreciation of the governing mechanism that causes the weakening of the interfacial bonds within the bi-layered tablet is crucial in order to improve the overall bi-layered tablet mechanical integrity. This work has shown that the occurrence of the elastic relaxation in the interface region during the ejection stage of the compaction process decreases with the increase in the bi-layered tablet interface strength. This is believed to be due to the increase in the plastic bonding in the interface region. The tablet diametrical elastic relaxation affects the tablet height elastic relaxation, where the impediment of the tablet height expansion is observed when the interface region experiences a diametrical expansion.
    Matched MeSH terms: Excipients/chemistry*
  16. Particle size analysis of nanocrystals: improved analysis method
    Keck CM
    Int J Pharm, 2010 May 5;390(1):3-12.
    PMID: 19733647 DOI: 10.1016/j.ijpharm.2009.08.042
    The influence of optical parameters, additional techniques (e.g. PIDS technology) and the importance of light microscopy were investigated by comparing laser diffraction data obtained via the conventional method and an optimized analysis method. Also the influence of a possible dissolution of nanocrystals during a measurement on the size result obtained was assessed in this study. The results reveal that dissolution occurs if unsaturated medium or microparticle saturated medium is used for the measurements. The dissolution is erratic and the results are not reproducible. Dissolution can be overcome by saturating the measuring medium prior to the measurement. If nanocrystals are analysed the dispersion medium should be saturated with the nanocrystals, because the solubility is higher than for coarse micro-sized drug material. The importance of using the optimized analysis method was proven by analysing 40 different nanosuspensions via the conventional versus the optimized sizing method. There was no large difference in the results obtained for the 40 nanosuspensions using the conventional method. This would have led to the conclusion, that all the 40 formulations investigated are physically stable. However, the analysis via the optimized method revealed that from 40 formulations investigated only four were physically stable. In conclusion an optimized analysis saves time and money and avoids misleading developments, because discrimination between "stable" and "unstable" can be done reliably at a very early stage of the development.
    Matched MeSH terms: Excipients/chemistry
  17. The transit of dosage forms through the small intestine
    Yuen KH
    Int J Pharm, 2010 Aug 16;395(1-2):9-16.
    PMID: 20478371 DOI: 10.1016/j.ijpharm.2010.04.045
    The human small intestine, with its enormous absorptive surface area, is invariably the principal site of drug absorption. Hence, the residence time of a dosage form in this part of the gut can have a great influence on the absorption of the contained drug. Various methods have been employed to monitor the gastrointestinal transit of pharmaceutical dosage forms, but the use of gamma-scintigraphy has superceded all the other methods. However, careful consideration of the time interval for image acquisition and proper analysis of the scintigraphic data are important for obtaining reliable results. Most studies reported the mean small intestinal transit time of various dosage forms to be about 3-4h, being closely similar to that of food and water. The value does not appear to be influenced by their physical state nor the presence of food, but the timing of food intake following administration of the dosage forms can influence the small intestinal transit time. While the mean small intestinal transit time is quite consistent among dosage forms and studies, individual values can vary widely. There are differing opinions regarding the effect of density and size of dosage forms on their small intestinal transit properties. Some common excipients employed in pharmaceutical formulations can affect the small intestinal transit and drug absorption. There is currently a lack of studies regarding the effects of excipients, as well as the timing of food intake on the small intestinal transit of dosage forms and drug absorption.
    Matched MeSH terms: Excipients/pharmacology
  18. Fulltext Effects of dynamic vulcanization on thermal properties of calcium carbonate filled polypropylene/ethylene propylene diene terpolymer composites
    Siti Rohana Ahmad, Salmah Husseinsyah, Kamarudin Hussin
    Pertanika Journal of Science & Technology, 2010;18(2):-.
    MyJurnal
    In this study, dynamic vulcanization process was used to improve the thermal properties of calcium carbonate filled composites. The composites were prepared using a Z-blade mixer at 180oC and rotor speed 50rpm. Thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) techniques were used to analyze the thermal properties of the composites. The vulcanized and unvulcanized PP/EPDM composites were filled by CaCO3 at 0, 10, 20, 30, and 40 %wt. Meanwhile, thermogravimetric analysis indicates that the total weight loss of PP/EPDM/CaCO3 composites decreased with increasing filler loading. Dynamic vulcanized composites have higher thermal stability, while the crystallinity of PP/EPDM/CaCO3 composites were increased as compared to unvulcanized composites. Therefore, the thermal properties were improved by the presence of
    dynamic vulcanization process.
    Matched MeSH terms: Excipients
  19. Fulltext The effect of polypropylene maleic anhydride (ppmah) on properties of polypropylene (pp)/recycled acrylonitrile butadiene rubber (nbrr)/ rice husk powder (rhp) composites
    Santiagoo, Ragunathan, Hanafi Ismail, Kamarudin Hussin
    Pertanika Journal of Science & Technology, 2010;18(2):-.
    MyJurnal
    The effect of polypropylene maleic anhydride (PPMAH) on tensile properties and morphology of polypropylene (PP)/recycled acrylonitrile butadiene rubber (NBRr)/ rice husk powder (RHP) composites has been studied. The composites were prepared through melt mixing at 180ºC for 9 minutes using 50 rpm rotor speed. The specimens were analyzed using different techniques, namely tensile test and Scanning Electron Microscopy (SEM). The results obtained showed that the tensile strength and Young’s modulus of the modified composites were increased, while the elongation at break showed the opposite trend as compared with the unmodified composites. The morphology results support the tensile properties and these indicated a better interaction between the filler and matrix with the presence of PPMAH as a compatibilizer.
    Matched MeSH terms: Excipients
  20. Fulltext Methane adsorption characteristics of copper oxide modified NaY zeolite adsorbents
    Kamarudin, K.S.N., Chieng, Y.Y., Hamdan, H., Mat, H.
    ASM Science Journal, 2010;4(1):29-40.
    MyJurnal
    Ordered microporous NaY zeolite and mesoporous copper oxide are high performance material as catalysts and adsorbents. The copper oxide-NaY zeolite modification in combination of their physicochemical properties could provide excellent opportunities for the creation of new gas adsorbents. In this study, modified NaY zeolite properties and methane adsorptive characteristics were investigated by dispersing copper oxide onto the NaY zeolite structure using the thermal dispersion method. The structures of the copper oxide modified zeolites were characterized by powder X-ray diffraction and Micromeritics ASAP 2000, while the methane adsorption characteristics were analyzed using a thermogravimetric analyzer. The results revealed that types of copper oxide, copper oxide loading concentration, calcination temperature and calcination time greatly affected the modified zeolite structure and gas methane adsorption characteristics.
    Matched MeSH terms: Excipients
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