Displaying publications 1 - 20 of 33 in total

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  1. 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: Technology, Pharmaceutical/methods*
  2. Principles and application of antibody libraries for infectious diseases
    Lim BN, Tye GJ, Choong YS, Ong EB, Ismail A, Lim TS
    Biotechnol Lett, 2014 Dec;36(12):2381-92.
    PMID: 25214212 DOI: 10.1007/s10529-014-1635-x
    Antibodies have been used efficiently for the treatment and diagnosis of many diseases. Recombinant antibody technology allows the generation of fully human antibodies. Phage display is the gold standard for the production of human antibodies in vitro. To generate monoclonal antibodies by phage display, the generation of antibody libraries is crucial. Antibody libraries are classified according to the source where the antibody gene sequences were obtained. The most useful library for infectious diseases is the immunized library. Immunized libraries would allow better and selective enrichment of antibodies against disease antigens. The antibodies generated from these libraries can be translated for both diagnostic and therapeutic applications. This review focuses on the generation of immunized antibody libraries and the potential applications of the antibodies derived from these libraries.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  3. 'Genipin' - the natural water soluble cross-linking agent and its importance in the modified drug delivery systems: an overview
    Manickam B, Sreedharan R, Elumalai M
    Curr Drug Deliv, 2014;11(1):139-45.
    PMID: 24041312
    One of the popular approaches in controlling drug delivery from the polymeric carriers is suitably achieved by the inclusion of crosslinking agents into the formulations at different concentrations. Nevertheless, addition of the chemical crosslinkers such as glutaraldehyde, formaldehyde etc, used in the drug delivery systems causes very serious cytotoxic reactions. These chemical crosslinking agents did not offer any significant advantageous effects when compared to the natural crosslinking agents for instance genipin, which is quite less toxic, biocompatible and offers very stable crosslinked products. Based on the earlier reports the safety of this particular natural crosslinker is very well established, since it has been widely used as a Chinese traditional medicine for long-time, isolated from fruits of the plant Gardenia jasminoides Ellis. This concise article largely portrayed the value of this unique natural crosslinker, utilized in controlling the drug delivery from the various formulations.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  4. Membrane separations
    Walter JK, Jin Z, Jornitz MW, Gorrschalk U
    Methods Biochem Anal, 2011;54:281-317.
    PMID: 21954783
    Matched MeSH terms: Technology, Pharmaceutical/methods
  5. Preparation, characterization, and in vitro release studies of insulin-loaded double-walled poly(lactide-co-glycolide) microspheres
    Ansary RH, Rahman MM, Awang MB, Katas H, Hadi H, Doolaanea AA
    Drug Deliv Transl Res, 2016 06;6(3):308-18.
    PMID: 26817478 DOI: 10.1007/s13346-016-0278-y
    The purpose of this study was to fabricate insulin-loaded double-walled and single-polymer poly(lactide-co-glycolide) (PLGA) microspheres using a fast degrading glucose core, hydroxyl-terminated poly(lactide-co-glycolide) (Glu-PLGA), and a moderate degrading carboxyl-terminated PLGA polymers. A modified water-in-oil-in-oil-in-water (w/o/o/w) emulsion solvent evaporation technique was employed to prepare double-walled microspheres, whereas single-polymer microspheres were fabricated by a conventional water-in-oil-in-water (w/o/w) emulsion solvent evaporation method. The effect of fabrication techniques and polymer characteristics on microspheres size, morphology, encapsulation efficiency, in vitro release, and insulin stability was evaluated. The prepared double-walled microspheres were essentially non-porous, smooth surfaced, and spherical in shape, whereas single-polymer microspheres were highly porous. Double-walled microspheres exhibited a significantly reduced initial burst followed by sustained and almost complete release of insulin compared to single-polymer microspheres. Initial burst release was further suppressed from double-walled microspheres when the mass ratio of the component polymers was increased. In conclusion, double-walled microspheres made of Glu-PLGA and PLGA can be a potential delivery system of therapeutic insulin.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  6. In Situ Gelling Ophthalmic Drug Delivery System: An Overview and Its Applications
    Sheshala R, Kok YY, Ng JM, Thakur RR, Dua K
    Recent Pat Drug Deliv Formul, 2015;9(3):237-48.
    PMID: 26205681
    Ophthalmic drug delivery system is very interesting and challenging due to the normal physiologically factor of eyes which reduces the bioavailability of ocular products. The development of new ophthalmic dosage forms for existing drugs to improve efficacy and bioavailability, patient compliance and convenience has become one of the main trend in the pharmaceuticals industry. The present review encompasses various conventional and novel ocular drug delivery systems, methods of preparation, characterization and recent research in this area. Furthermore, the information on various commercially available in situ gel preparations and the existing patents of in situ drug delivery systems i.e. in situ gel formation of pectin, in situ gel for therapeutic use, medical uses of in situ formed gels and in situ gelling systems as sustained delivery for front of eye are also covered in this review.
    Matched MeSH terms: Technology, Pharmaceutical/methods*
  7. Nanospray Drying Technology: Existing Limitations and Future Challenges
    Wui WT
    Recent Pat Drug Deliv Formul, 2015;9(3):185-6.
    PMID: 25966873
    Matched MeSH terms: Technology, Pharmaceutical/methods*
  8. Fulltext A Time-Domain NMR Study of the State of Water in Wet Granules with Different Fillers and Its Contribution to the Wet Granulation Process and to the Characteristics of Granules
    Ito T, Okada K, Leong KH, Hirai D, Hayashi Y, Kumada S, et al.
    Chem Pharm Bull (Tokyo), 2019;67(3):271-276.
    PMID: 30828004 DOI: 10.1248/cpb.c18-00888
    The different states of water incorporated in wet granules were studied by a low-field benchtop 1H-NMR time-domain NMR (TD-NMR) instrument. Wet granules consisting different fillers [cornstarch (CS), microcrystalline cellulose (MCC), and D-mannitol (MAN)] with different water contents were prepared using a high-speed granulator, and then their spin-spin relaxation time (T2) was measured using the NMR relaxation technique. The experimental T2 relaxation curves were analyzed by the two-component curve fitting, and then the individual T2 relaxation behaviors of solid and water in wet granules were identified. According to the observed T2 values, it was confirmed that the molecular mobility of water in CS and MCC granules was more restricted than that in the MAN granule. The state of water appeared to be associated with the drying efficiency and moisture absorption capacity of wet granules. Thus, it was confirmed that the state of water significantly affected the wet granulation process and the characteristics of the resultant granules. In the final phase of this study, the effects of binders on the molecular mobility of water in granulation fluids and wet granules were examined. The state of water in granulation fluids was substantially changed by changing the binders. The difference was still detected in wet granules prepared by addition of these fluids to the fillers. In conclusion, TD-NMR can offer valuable knowledge on wet granulation from the viewpoint of molecular mobility of water.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  9. Microwave non-destructive testing technique for characterization of HPMC-PEG 3000 films
    Wong TW, Deepak KG, Taib MN, Anuar NK
    Int J Pharm, 2007 Oct 1;343(1-2):122-30.
    PMID: 17597317
    The capacity of microwave non-destructive testing (NDT) technique to characterize the matrix property of binary polymeric films for use as transdermal drug delivery system was investigated. Hydroxypropylmethylcellulose (HPMC) and polyethylene glycol (PEG) 3000 were the choice of polymeric matrix and plasticizer, respectively with loratadine as the model drug. Both blank and drug loaded HPMC-PEG 3000 films were prepared using the solvent-evaporation method. These films were conditioned at the relative humidity of 25, 50 and 75% prior to physicochemical characterization using the established methods of ultra-violet spectrophotometry, differential scanning calorimetry and Fourier transform infrared spectroscopy methods, as well as, novel microwave NDT technique. Blank films exhibited a greater propensity of polymer-polymer interaction at the O-H domain upon storage at a lower level of relative humidity, whereas drug loaded films exhibited a greater propensity of polymer-polymer, polymer-plasticizer and/or drug-polymer interaction via the O-H, C-H and/or aromatic C=C functional groups when they were stored at a lower or moderate level of relative humidity. The absorption and transmission characteristics of both blank and drug loaded films for microwave varied with the state of polymer-polymer, polymer-plasticizer, and/or drug-polymer interaction of the matrix. The measurements of microwave NDT test at 8 and 12 GHz were sensitive to the polar fraction of film involving functional group such as O-H moiety and the less polar environment of matrix consisting of functional groups such as C-H and aromatic C=C moieties. The state of interaction between polymer, plasticizer and/or drug of a binary polymeric film can be elucidated through its absorption and transmission profiles of microwave.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  10. Centrifugal air-assisted melt agglomeration for fast-release "granulet" design
    Wong TW, Musa N
    Int J Pharm, 2012 Jul 1;430(1-2):184-96.
    PMID: 22531845 DOI: 10.1016/j.ijpharm.2012.04.026
    Conventional melt pelletization and granulation processes produce round and dense, and irregularly shaped but porous agglomerates respectively. This study aimed to design centrifugal air-assisted melt agglomeration technology for manufacture of spherical and yet porous "granulets" for ease of downstream manufacturing and enhancing drug release. A bladeless agglomerator, which utilized shear-free air stream to mass the powder mixture of lactose filler, polyethylene glycol binder and poorly water-soluble tolbutamide drug into "granulets", was developed. The inclination angle and number of vane, air-impermeable surface area of air guide, processing temperature, binder content and molecular weight were investigated with reference to "granulet" size, shape, texture and drug release properties. Unlike fluid-bed melt agglomeration with vertical processing air flow, the air stream in the present technology moved centrifugally to roll the processing mass into spherical but porous "granulets" with a drug release propensity higher than physical powder mixture, unprocessed drug and dense pellets prepared using high shear mixer. The fast-release attribute of "granulets" was ascribed to porous matrix formed with a high level of polyethylene glycol as solubilizer. The agglomeration and drug release outcomes of centrifugal air-assisted technology are unmet by the existing high shear and fluid-bed melt agglomeration techniques.
    Matched MeSH terms: Technology, Pharmaceutical/methods*
  11. Gas-pressurized dispersive powder flow tester for low volume sample characterization
    Majid AM, Wong TW
    Int J Pharm, 2013 May 1;448(1):150-8.
    PMID: 23506957 DOI: 10.1016/j.ijpharm.2013.03.008
    The conventional powder flow testers require sample volumes larger than 40g and are met with experimental hiccups due to powder cohesion. This study designed a gas-pressurized dispersive powder flow tester where a high velocity air is used to disaggregate powder (9g) and eliminate its cohesion. The pressurized gas entrained solid particles leaving an orifice where the distance, surface area, width and weight of particle dispersion thereafter are determined as flow index. The flow indices of seven lactose grades with varying size, size distribution, shape, morphology, bulk and tapped densities characteristics were examined. They were compared against Hausner ratio and Carr's index parameters of the same powder mass. Both distance and surface area attributes of particle dispersion had significant negative correlations with Hausner ratio and Carr's index values of lactose. The distance, surface area and ease of particle dispersion varied proportionately with circular equivalent, surface weighted mean and volume weighted mean diameters of lactose, and inversely related to their specific surface area and elongation characteristics. Unlike insensitive Hausner ratio and Carr's index, an increase in elongation property of lactose particles was detectable through reduced powder weight loss from gas-pressurized dispersion as a result of susceptible particle blockage at orifice. The gas-pressurized dispersive tester is a useful alternative flowability measurement device for low volume and cohesive powder.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  12. A review of bacterial cellulose-based drug delivery systems: their biochemistry, current approaches and future prospects
    Abeer MM, Mohd Amin MC, Martin C
    J Pharm Pharmacol, 2014 Aug;66(8):1047-61.
    PMID: 24628270 DOI: 10.1111/jphp.12234
    The field of pharmaceutical technology is expanding rapidly because of the increasing number of drug delivery options. Successful drug delivery is influenced by multiple factors, one of which is the appropriate identification of materials for research and engineering of new drug delivery systems. Bacterial cellulose (BC) is one such biopolymer that fulfils the criteria for consideration as a drug delivery material.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  13. Fulltext Using transgenic plants and modified plant viruses for the development of treatments for human diseases
    Loh HS, Green BJ, Yusibov V
    Curr Opin Virol, 2017 10;26:81-89.
    PMID: 28800551 DOI: 10.1016/j.coviro.2017.07.019
    Production of proteins in plants for human health applications has become an attractive strategy attributed by their potentials for low-cost production, increased safety due to the lack of human or animal pathogens, scalability and ability to produce complex proteins. A major milestone for plant-based protein production for use in human health was achieved when Protalix BioTherapeutics produced taliglucerase alfa (Elelyso®) in suspension cultures of a transgenic carrot cell line for the treatment of patients with Gaucher's disease, was approved by the USA Food and Drug Administration in 2012. In this review, we are highlighting various approaches for plant-based production of proteins and recent progress in the development of plant-made therapeutics and biologics for the prevention and treatment of human diseases.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  14. Punctal plug: a medical device to treat dry eye syndrome and for sustained drug delivery to the eye
    Yellepeddi VK, Sheshala R, McMillan H, Gujral C, Jones D, Raghu Raj Singh T
    Drug Discov Today, 2015 Jul;20(7):884-9.
    PMID: 25668579 DOI: 10.1016/j.drudis.2015.01.013
    Punctal plugs (PPs) are miniature medical implants that were initially developed for the treatment of dry eyes. Since their introduction in 1975, many PPs made from different materials and designs have been developed. PPs, albeit generally successful, suffer from drawbacks such as epiphora and suppurative canaliculitis. To overcome these issues intelligent designs of PPs were proposed (e.g. SmartPLUG™ and Form Fit™). PPs are also gaining interest among pharmaceutical scientists for sustaining drug delivery to the eye. This review aims to provide an overview of PPs for dry eye treatment and drug delivery to treat a range of ocular diseases. It also discusses current challenges in using PPs for ocular diseases.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  15. Drug release property of chitosan-pectinate beads and its changes under the influence of microwave
    Wong TW, Nurjaya S
    Eur J Pharm Biopharm, 2008 May;69(1):176-88.
    PMID: 17980563
    The effects of microwave irradiation on the drug release property of pectinate beads loaded internally with chitosan (chitosan-pectinate beads) were investigated against the pectinate beads and beads coacervated with chitosan externally (pectinate-chitosonium beads). These beads were prepared by an extrusion method using sodium diclofenac as the model water-soluble drug. The beads were subjected to microwave irradiation at 80 W for 5, 10, 21 and 40 min. The profiles of drug dissolution, drug content, drug-polymer interaction and polymer-polymer interaction were determined by drug dissolution testing, drug content assay, drug adsorption study, differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR) techniques. Treatment of pectinate beads by microwave did not lead to a decrease, but an increase in the extent of drug released at 4h of dissolution owing to reduced pectin-pectin interaction via the CO moiety of polymer. In addition, the extent of drug released from the pectinate beads could not be reduced merely through the coacervation of pectinate matrix with chitosan. The reduction in the extent of drug released from the pectinate-chitosonium beads required the treatment of these beads by microwave, following an increase in drug-polymer and polymer-polymer interaction in the matrix. The extent of drug released from the pectinate beads was reduced through incorporating chitosan directly into the interior of pectinate matrix, owing to drug-chitosan adsorption. Nonetheless, the treatment of chitosan-pectinate matrix by microwave brought about an increase in the extent of drug released unlike those of pectinate-chitosonium beads. Apparently, the loading of chitosan into the interior of pectinate matrix could effectively retard the drug release without subjecting the beads to the treatment of microwave. The microwave was merely essential to reduce the release of drug from pectinate beads when the chitosan was introduced to the pectinate matrix by means of coacervation. Under the influences of microwave, the drug release property of beads made of pectin and chitosan was mainly modulated via the CH, OH and NH moieties of polymers and drug, with CH functional group purported to retard while OH and NH moieties purported to enhance the drug released from the matrix.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  16. Gelatine enhances drug dispersion in alginate bilayer film via the formation of crystalline microaggregates
    Thu HE, Ng SF
    Int J Pharm, 2013 Sep 15;454(1):99-106.
    PMID: 23856162 DOI: 10.1016/j.ijpharm.2013.06.082
    In our previous study, a novel alginate-based bilayer film for slow-release wound dressings was successfully developed. We found that alginate alone yielded poor films; however, the addition of gelatine had significantly enhanced the drug dispersion as well as the physical properties. Here, an investigation of the drug-polymer interactions in the bilayer films was carried out. Drug content uniformity test and microscopy observation revealed that the addition of gelatine generated bilayer films with a homogenous drug distribution within the matrix. The FTIR and XRD data showed an increase in film crystallinity which might infer the presence of drug-polymer crystalline microaggregates in the films. DSC confirmed the drug-polymer interaction and indicated that the gelatine has no effect on the thermal behaviour of the microaggregates, suggesting the compatibility of the drug and excipients in the bilayer films. In conclusion, the addition of gelatine can promote homogenous dispersion of hydrophobic drugs in alginate films possibly through the formation of crystalline microaggregates.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  17. Nano-formulations of drugs: Recent developments, impact and challenges
    Jeevanandam J, Chan YS, Danquah MK
    Biochimie, 2016 Sep-Oct;128-129:99-112.
    PMID: 27436182 DOI: 10.1016/j.biochi.2016.07.008
    Nano-formulations of medicinal drugs have attracted the interest of many researchers for drug delivery applications. These nano-formulations enhance the properties of conventional drugs and are specific to the targeted delivery site. Dendrimers, polymeric nanoparticles, liposomes, nano-emulsions and micelles are some of the nano-formulations that are gaining prominence in pharmaceutical industry for enhanced drug formulation. Wide varieties of synthesis methods are available for the preparation of nano-formulations to deliver drugs in biological system. The choice of synthesis methods depend on the size and shape of particulate formulation, biochemical properties of drug, and the targeted site. This article discusses recent developments in nano-formulation and the progressive impact on pharmaceutical research and industries. Additionally, process challenges relating to consistent generation of nano-formulations for drug delivery are discussed.
    Matched MeSH terms: Technology, Pharmaceutical/methods*
  18. In Vitro Investigation of Influences of Chitosan Nanoparticles on Fluorescein Permeation into Alveolar Macrophages
    Chachuli SH, Nawaz A, Shah K, Naharudin I, Wong TW
    Pharm Res, 2016 06;33(6):1497-508.
    PMID: 26951565 DOI: 10.1007/s11095-016-1893-5
    PURPOSE: Pulmonary infection namely tuberculosis is characterized by alveolar macrophages harboring a large microbe population. The chitosan nanoparticles exhibit fast extracellular drug release in aqueous biological milieu. This study investigated the matrix effects of chitosan nanoparticles on extracellular drug diffusion into macrophages.

    METHODS: Oligo, low, medium and high molecular weight chitosan nanoparticles were prepared by nanospray drying technique. These nanoparticles were incubated with alveolar macrophages in vitro and had model drug sodium fluorescein added into the same cell culture. The diffusion characteristics of sodium fluorescein and nanoparticle behavior were investigated using fluorescence microscopy, scanning electron microscopy, differential scanning calorimetry and Fourier transform infrared spectroscopy techniques.

    RESULTS: The oligochitosan nanoparticles enabled macrophage membrane fluidization with the extent of sodium fluorescein entry into macrophages being directly governed by the nanoparticle loading. Using nanoparticles made of higher molecular weight chitosan, sodium fluorescein permeation into macrophages was delayed due to viscous chitosan diffusion barrier at membrane boundary.

    CONCLUSION: Macrophage-chitosan nanoparticle interaction at membrane interface dictates drug migration into cellular domains.

    Matched MeSH terms: Technology, Pharmaceutical/methods
  19. A stable hydrocortisone nanosuspension for improved dissolution: Preparation, characterization and in vitro evaluation
    Ali HS, Khan S, York P, Shah SM, Khan J, Hussain Z, et al.
    Pak J Pharm Sci, 2017 Sep;30(5):1635-1643.
    PMID: 29084684
    Drug nanosuspensions have gained tremendous attraction as a platform in drug delivery. In the present work, a nanosuspension was prepared by a wet milling approach in order to increase saturation solubility and dissolution of the water insoluble drug, hydrocortisone. Size of the generated particeles was 290 nm ± 9 nm having a zeta potential of -1.9 mV ± 0.6 mV. Nanosized particles were found to have a rod shape with a narrow particle size distribution (PDI =0.17). Results of differential scanning calorimetry and X-ray diffraction analyses revealed minor modifications of crystallinity of hydrocortisone following the milling process. Solubility of hydrocortisone was enhanced by nanonization to 875µg/ml ±2.5, an almost 2.9-fold compared to the raw hydrocortisone. Moreover, the nanosuspension formulation substabtially enhanced the dissolution rate of hydrocortisone where >97% of the hydrocortisone was dissolved within 10 minutes opposed to 22.3% for the raw 50% for the raw hydrocortisone and the commercial tablet, respectively. The bioavailability study resulted in AUC 0-9h for HC nanosuspensions (31.50±2.50), which is significantly (p<0.05) higher compared to the AUC 0-9h (14.85±3.25) resulted for HC solution. The nanosuspension was physically stable at room temperature for 24 months.
    Matched MeSH terms: Technology, Pharmaceutical/methods
  20. RP-HPLC analytical method development and optimization for quantification of donepezil hydrochloride in orally disintegrating tablet
    Liew KB, Peh KK, Fung Tan YT
    Pak J Pharm Sci, 2013 Sep;26(5):961-6.
    PMID: 24035953
    An easy, fast and validated RV-HPLC method was invented to quantify donepezil hydrochloride in drug solution and orally disintegrating tablet. The separation was carried out using reversed phase C-18 column (Agilent Eclipse Plus C-18) with UV detection at 268 nm. Method optimization was tested using various composition of organic solvent. The mobile phase comprised of phosphate buffer (0.01M), methanol and acetonitrile (50:30:20, v/v) adjusted to pH 2.7 with phosphoric acid (80%) was found as the optimum mobile phase. The method showed intraday precision and accuracy in the range of 0.24% to -1.83% and -1.83% to 1.99% respectively, while interday precision and accuracy ranged between 1.41% to 1.81% and 0.11% to 1.90% respectively. The standard calibration curve was linear from 0.125 μg/mL to 16 μg/mL, with correlation coefficient of 0.9997±0.00016. The drug solution was stable under room temperature at least for 6 hours. System suitability studies were done. The average plate count was > 2000, tailing factor <1, and capacity factor of 3.30. The retention time was 5.6 min. The HPLC method was used to assay donepezil hydrochloride in tablet and dissolution study of in-house manufactured donepezil orally disintegrating tablet and original Aricept.
    Matched MeSH terms: Technology, Pharmaceutical/methods*
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