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Effect of Particle Size of Chitosan on Drug Release from Layered Matrix System Comprising Chitosan and Xanthan Gum
Get PDFBiopolymers such as chitosan and xanthan gum were applied as matrix component for fabrication into tablet using a direct compression technique to control the release of propranolol HCl. Covering both planar surfaces of middle tablet with polymeric mixture containing chitosan-xanthan gum-lactose could modulate the release of propranolol HCl. Increased amount of lactose enhanced the drug release and diminished the pH sensitive drug release of tablet containing chitosan and xanthan gum. However, the drug release from the three layer tablets comprising this system was pH dependent. Particle size of chitosan did not significantly affect the drug release from the three layer tablets comprising this system. The drug release behaviour from the developed tablets was characterized with the curve fitting with different mathematical equations and the water & erosion studies.Key words: chitosan, drug release layered matrix, particle size, xanthan gu
Comparison Drug Release from Simple and Layered Matrix Systems Containing Hydroxypropyl Methylcellulose
Get PDFObjective: The aim of this investigation was to compare the release behavior of propranolol HCl from simple matrix and layeredtablets containing HPMC and phytowax as matrix component using direct compression technique.Method: The test of drug release was performed in distilled water during 26 hrs using a dissolution apparatus and thereafter thedissolution profile fitting to different mathematical equations was carried out using least square fitting with a nonlinear computerprogram, Scientist for Windows, version 2.1.Results: Covering both planar surfaces of drug-loaded middle layer was able to attain a more sustainable drug release than asimple matrix which composed the same amount of matrix component. Additionally, the near-zero order release could beobtained for the first system whereas the drug release from simple matrix tablet was diffusion-controlled. As the number oramount of coating layer, and amount of matrix component in middle layer were increased, the drug release was noticeablyprolonged. Drug release from layered tablets was influenced by hydrodynamic force and incorporated diluents.Conclusion: Effective near-zero order controlled release of hydrophilic drug was obtained from three-layered matrix tabletscomprising HPMC as main matrix component. Modulation of drug release could be conducted by addition or increasing amountof water soluble substances into the matrix component of three-layered tablets.Key words: drug release, comparison, simple layered-matrix, layered-matrix, hydroxypropyl methylcelluloseThai Pharm Health Sci J 2008;3(2):219-228
Drug Release through PEG-Xanthan Gum-Lactose Matrix Comprising Different Amount of Drug
Get PDFObjective: The purpose of this study is to investigate the effect of xanthan gum and lactose on the physical and releaseproperties of 25-mg and 75-mg indomethacin tablets containing polyethylene glycol (PEG) prepared by mold technique. Method:The physical and drug release characteristics of developed matrix tablet were studied. Least square fitting the experimentaldissolution data to the mathematical expressions (power law, first order, Higuchi’s and zero order) was carried out. Results:Because of the more completion dissolution of drug in PEG matrix, the drug release from the lower-drug loading tablet wasfaster than the higher-drug loading tablet. An addition of xanthan gum could sustain the drug release whereas an addition oflactose diminished the drug dissolution. From curve fitting, most drug release profiles were primarily as Fickian diffusion.Conclusion: Amount of indomethacin played an important role on the drug released from PEG matrix consisting xanthan gumand lactose prepared with fusion and mold technique. Xanthan gum and lactose also affected the physical and releasecharacteristics of these investigated indomethacin tablets.Keywords: Characterization, drug, release, mold tablet, hydroxypropyl methylcellulose, polyethylene glycolThai Pharm Health Sci J 2009;4(2):153-163
Benzoyl Peroxide:Current Status and Its Delivery System
No full textBenzoyl peroxide is an organic compound which has been use for various purposes including treatment for acne, Hong Kong foot and chronic ulcers
Eutectic System in Pharmaceutical Applications
Get PDFEutectics are mixtures of at least two compounds with a uniqueproperty that such system has a lower melting temperature than thatof either constituent alone. This decrease in melting point can bescrutinized profoundly from thermodynamics theory which suggeststhat there is an increase in total entropy of the system. Furthermore,such thermodynamic equation could be utilized to determine theeutectic critical parameters such as eutectic point or eutecticcomposition employing the data form differential scanningcalorimetric and hot stage microscope. With the increasing totalentropy, the solubility and permeability ability of eutectics areenhanced apparently. Some liquid eutectics can be utilized assolvent/co-solvent system, and biotransformation medium. Somedrawbacks of eutectics include formulary incompatibilities which mayaffect stability or properties of the formula.Keywords:eutectic, thermodynamic, theory, pharmaceutica
Thermal Properties and Rheological Behaviors of the Anesthetic Gel Containing Lidocaine and Prilocaine
Get PDFObjectives: To develop a gel containing lidocaine and prilocaine and to characterize its thermal and rheological properties. Methods: The thermal property by differential scanning calorimeter (DSC), solubility of the drugs in co-solvent system, suitable gelling agent and rheological behavior were evaluated. Results: DSC study revealed that lidocaine:prilocaine at the ratio of 1:1 could form a eutectic mixture. The co-solvent system, 35% w/w ethanol was used to dissolve these drugs. The 1% w/w carbopol 940 was an appropriate gelling agent. The developed gel and EMLA® cream showed a comparable pseudoplastic flow (shear thinning system). In addition, the changing of temperature did not affect the gels’ rheological behavior. Conclusion: This study of the lidocaine-prilocaine gel formulation can be useful for the further development. Keyword: lidocaine, prilocaine, gel, eutectic mixture, thermal properties, rheological behavior
เทคโนโลยีหุ่นยนต์ขนาดไมโครเมตรหรือนาโนเมตรเพื่อใช้ทางการแพทย์และเภสัชกรรม Micro or Nano-robotic Technology for Medical and Pharmaceutical Applications
Get PDFAbstract Nowadays the development of robots in medicine or pharmaceutical applications is important for disease diagnosis and drug delivery system. The goal of this study is to increase the efficiency of diagnosis or treatment to facilitate drug delivery and reduce the side effects of traditional treatment. Most designed robotic technology delivers the machine into an area where the disease or disorder occur which the tiny robots as micro and nano-scale are required using complex designs with different technologies including mechanical and chemical procedures. Keywords: robotic technology, micrometer, nanometer, medical, pharmaceutica
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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