Comparison Drug Release from Simple and Layered Matrix Systems Containing Hydroxypropyl Methylcellulose

Objective: 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

Effect of Particle Size of Chitosan on Drug Release from Layered Matrix System Comprising Chitosan and Xanthan Gum

Biopolymers 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

Drug Release through PEG-Xanthan Gum-Lactose Matrix Comprising Different Amount of Drug

Objective: 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

Thermal Properties and Rheological Behaviors of the Anesthetic Gel Containing Lidocaine and Prilocaine

Objectives: 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

Numerical investigation of cell encapsulation for multiplexing diagnostic assays using novel centrifugal microfluidic emulsification and separation platform

In the present paper, we report a novel centrifugal microfluidic platform for emulsification and separation. Our design enables encapsulation and incubation of multiple types of cells by droplets, which can be generated at controlled high rotation speed modifying the transition between dripping-to-jetting regimes. The droplets can be separated from continuous phase using facile bifurcated junction design. A three dimensional (3D) model was established to investigate the formation and sedimentation of droplets using the centrifugal microfluidic platform by computational fluid dynamics (CFD). The simulation results were compared to the reported experiments in terms of droplet shape and size to validate the accuracy of the model. The influence of the grid resolution was investigated and quantified. The physics associated with droplet formation and sedimentation is governed by the Bond number and Rossby number, respectively. Our investigation provides insight into the design criteria that can be used to establish centrifugal microfluidic platforms tailored to potential applications, such as multiplexing diagnostic assays, due to the unique capabilities of the device in handling multiple types of cells and biosamples with high throughput. This work can inspire new development of cell encapsulation and separation applications by centrifugal microfluidic technolog

Total Phenolic Content and Antioxidant Activity of Fresh and Preserved Fruits of Ellaeocarpus hygrophilus Kurz.

Objective: To determine the total phenolic content and antioxidant activities of fresh Spanish plum fruits (Ellaeocarpus hygrophilus Kurz., family Elaeocarpaceae.) in various ages and to examine the influence of preserved methods which were chilling and pickling on the total phenolic content and antioxidant activities of the fruit. Method: The meat of Spanish plum fruit was preserved by storage at -70, -4, 0 and 4 °C for 1, 4 and 6 months. Results: The duration and temperature of storage resulted in no significant effect on pH of the fruit juice. The various durations of chilling showed no significantly different effect on % brix of the fruits, but lower chilling temperature was associated with increased % brix. The younger fruit contained higher amount of total phenols in its crude extracts and juice than the older ones. The duration of chilling showed no effect on total phenols of the fruits. The duration and temperature of chilling of the fruits before juice squeezing gave significant decreasing effect on the amount of total phenols in the juices. The antioxidant activities of the fruits with all ages were low. The duration and temperature of chilling and prickle duration of the fruits had no significant effect on antioxidant activities. Conclusion: The preserved condition could save pH, % brix, amount of total phenol and antioxidant activities of the Spanish plum fruit.Keywords: Spanish plum, Ellaeocarpus hygrophilus Kurz, antioxidant activity, phenolic compounds, preserved frui

HPMC Matrix Granule Formation: Selection of Suitable Granulating Fluid

Objective: The purpose of this study was to investigate and select the suitable granulating fluid for the matrix granules consisting of hydroxypropyl methylcellulose (HPMC).Method: Viscosity of the granulating fluids containing HPMC in different solvents was determined. The matrix granules obtained from mixing the granulating fluid with propranolol HCl, HPMC and lactose were assessed for bulk density, particle size distribution, flowability and friability. SEM, DSC, powder x-ray diffraction and drug dissolution studies were conducted to characterize the physical properties of the granules.Results: Type of granulating liquid affected the granule properties. The utilization of isopropyl alcohol as a granulating liquid and subsequently adding with water was a suitable system for agglomeration of powders. Good physical properties were obtained for the granule prepared by using this granulating fluid.Conclusion: Type of solvent and amount of water played an important role for physical properties of HPMC in the formation of the matrix granule due to the hydrophilicity and gel formation of this polymer. The use of isopropyl alcohol as granulating liquid and subsequently adding with water was a suitable process in producing the matrix granules consisting of HPMC.Keywords: hydroxypropyl methylcellulose, matrix granule, granulating flui

Utilization Feasibility of Emulsifying Polymers in Cream Base

ABSTRACTObjective: Emulsifying polymer has been employed for low energy emulsification. This study investigated effect of some crucial factorson the physical properties of cream prepared from these polymers. Method: Systems containing various emulsifying polymers, distilledwater and isopropyl isostearate were prepared. Formula and process variables including type and amount of emulsifying polymer, typeand amount of solvents, and order of mixing on physical properties of cream base, were evaluated. Results: Viscosity of emulsions wasincreased as amount of emulsifying polymer was increased. Additionally, viscosity of systems depended on the type of emulsifyingpolymer and the type of solvent. Viscosity of formulation was different as order of mixing was changed. Conclusion: Type and amount ofemulsifying polymers or solvent and order of mixing notably affected viscosity of cream base. However, these polymeric emulsifiers havepotential use for emulsion both in pharmaceutical and cosmetic products.Keywords: cream base, emulsifying polymers, utilizationThai Pharm Health Sci J 2009;4(4):456-462

ยาสีฟันฟอกฟันขาว Whitening Toothpaste

ความไม่พึงพอใจในสีของฟันและความต้องการให้ฟันมีสีขาวขึ้นทำให้เกิดการพัฒนาผลิตภัณฑ์ยาสีฟันฟอกฟันขาว ยาสีฟันฟอกฟันขาวมีส่วนประกอบสำคัญคือ สารขัดฟัน สารเคมีทำให้ฟันขาว และสารย้อมสีฟัน เพื่อช่วยขัดฟันและทำให้คราบสีที่ติดอยู่จางลง รวมทั้งป้องกันการเกิดคราบบนผิวฟันซึ่งเป็นสาเหตุของการเกิดฟันเหลือง วิธีการประเมินตำรับยาสีฟันฟอกฟันขาวที่สำคัญ คือ การประเมินภายนอกร่างกาย โดยการวัดการลดคราบบนผิวฟันวัวด้วยเครื่องวัดสี และการประเมินภายในร่างกาย โดยใช้อาสาสมัครที่มีคราบบนผิวฟันทำการแปรงฟันด้วยยาสีฟันฟอกฟันขาว และบันทึกระดับความเข้มของคราบบนผิวฟันที่ลดลงตามช่วงเวลาที่ทำการทดลองด้วยเครื่องวัดสี ปัจจุบันมีรายงานการใช้ยาสีฟันฟอกฟันขาวว่าสามารถขจัดคราบเหลืองบนผิวฟันและทำให้ฟันขาวขึ้นได้มากกว่ายาสีฟันผสมฟลูออไรด์ และการเติมสารย้อมสีฟันลงในยาสีฟันสามารถลดคราบบนผิวฟันและส่งเสริมให้ฟันขาว คำสำคัญ: การเปลี่ยนสีฟันเปลี่ยน,  ยาสีฟันฟอกฟันขาว,  การฟอกสีฟันขาวThe dissatisfaction in teeth color and the desire for teeth whitening are the reason whitening toothpaste products have been developed. The important ingredients of whitening toothpaste for discoloration improvement, yellow plaque removal and prevention of plaque formation are as follows: abrasives, teeth whitening chemicals and opacifying agent. The major evaluation methods of whitening toothpaste are 1) ex vivo evaluation, for example, the measurement for decreasing plaque on stained cow teeth using colorimeter and 2) in vivo evaluation by recording the decrement of stained teeth of volunteers after brushing with whitening toothpaste using colorimeter. Presently, there is the report indicating that whitening toothpaste is more effective than using fluoride toothpaste in yellow stained teeth surface removal and remaining the whiten teeth. The addition of coloring agent stains on tooth enamel and promotes teeth whitening. Keywords: teeth discoloration, whitening toothpaste, teeth whitening

เทคโนโลยีหุ่นยนต์ขนาดไมโครเมตรหรือนาโนเมตรเพื่อใช้ทางการแพทย์และเภสัชกรรม Micro or Nano-robotic Technology for Medical and Pharmaceutical Applications

Abstract 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