1,720,961 research outputs found
Evaluation of Ethylcellulose-Coated pellets Optimized using the Approach of Taguchi
No full textSpherical granules of theophylline with microcrystalline cellulose and lactose were prepared in a high-speed granulator. An original experimental design based on the philosophy of Taguchi was applied to optimize the yield of the produced granules. Successively, the optimized pellets were coated with an ethylcellulose pseudolatex preparation (Surelease®) in a fluid bed coating machine using a bottom spray noule and a Wurster® column. Finally, these granules were c ompressed into tablets of different hardnesses. The chosen statistical approach proved efficient not only to find the optimal operating conditions for granulation but it also appeared to define the characteristics of a process that was robust and no sensitive to noise factors. Dissolution studies revealed a zero-order release of theophylline from the coated granules, but after the compression step, the ethyl cellulose film was damaged and the drug release was immediate
Evaluation of spray-drying as a method to prepare microparticles for controlled drug release
No full textThe possibility to obtain microcapsules or microspheres for controlled release by spray-drying is evaluated. Drugs of different solubilities like theophylline and sodium sulfamethazine, with Eudragit RS as coating polymer, are chosen.
The polymer is used, either dissolved in an hydroalcoholic solution or suspended (pseudolatex) in water, in different weight ratios with the drug. The obtained solution or suspension is spray-dried.
Scanning electron microscope analysis of the powders reveals no sign of microencapsulation. Moreover, only a fraction of the particles has a spherical shape.
For each spray-dried powder, a part of the obtained particles is compressed into tablets, and the rest is stored.
Dissolution studies in distilled water at 37 C are performed on powders and tablets.
While the uncompressed microparticles do not give any controlled release, the tablets show an ability in slowing down drug delivery greater than the one obtained with the traditional methods
Comparison of different methods to complex water-or liposoluble vitamins
No full textIn order to complex water or liposoluble vitamins different inclusion complexation methods were studied. Solid dispersion, kneading, grinding, freeze-drying and spray-drying of b-cyclodextrin with different vitamins were compared using differential scanning calorimetry, X-ray diffractometry, nuclear magnetic resonance and high pressure liquid chromatography. The obtained results proved efficient to select the best method for each kind of studied vitamins
Drug release from compressed Eudragit RS 30D coated beads
No full textTablets of different hardnesses and compositions were prepared with an original theophylline granulate previously coated with Eudragit RS 30D. Dissolution studies of each tablet formulation were performed to verify any kinetic variationfrom the dissolution profile. This was obtained by filling with the same coated granules in a hard gelatine capsule. While the dissolution profiles of the capsules possesses very good linearity, the tablet kinetics gradually deviate from this linearity with an increase in the percentage of the coated granules in the formulation. Tablet hardness has only a marginal influence on this kinetic deviation
The Taguchi's performance statistic to optimize Theophylline beads production in a high-speed granulator.
No full textAn original process using a simple procedure is developed to produce theophylline active pellets. In order to improve this process, an optimization approach is applied. But rather than only trying to bring the process to the target optimal values, attempt is made to find operating conditions leading also to stable and non-sensitive pellets characteristics. In this purpose, the classic experimental design approach and response surface methodology are completed by using Taguchi's philosophy
Interactions between Lonidamine and b- or hydroxypropyl -b- cyclodextrin
No full textThe possibility of obtaining inclusion complexes between lonidamine and β- or hydroxypropyl-β-cyclodextrin have been evaluated by phase solubility diagram, differential scanning calorimetry (DSC), and x-ray diffractometry. The applied complexation methods were spray-drying, kneading, and solid dispersion. DSC and x-ray analyses of the powders revealed an external interaction between lonidamine and cyclodextrins. Dissolution profiles of the obtained powders were also studied to define the most appropriate preparation method and molar ratio to use in attempts to increase lonidamine water solubility
Aqueous acrylic resin for coating an original theophylline granulate
No full textSpherical granules of theophylline, microcrystalline cellulose and lactose are prepared in a high speed granulator using an original method. Successively, the fraction of granules selected is coated with Eudragit RS 30D in a fluid bed coating machine using the bottom spray system and the wurster column. Finally, these granules are compressed into tablets of different hardnesses.
Dissolution studies reveal a zero order release of theophylline from the coated granules. After compression, the kinetics is modified but the tablets remain efficient to control the theophylline release during 8 hours
Gelatin-Acacia complex coacervation as a method for Ketoprofen microencapsulation
No full textKetoprofen microcapsules were prepared by complex coacervation between gelatin and acacia, and dried with different methods: isopropanol addition, spray-drying, and freeze-drying, Successively, microparticles were analyzed by infrared thembalance, ultraviolet spectroscopy, optical and scanning electron microscopy, and sieves; and subjected to dissolution studies in order to examine parameters such as yield, moisture content, encapsulation percentage, morphology of solid particles, particle size, and dissolution behavior. Provided that encapsulation and drying methods did not affect ketoprofen dissolution profiles, the most appropriate drying method for industrial purposes was spray-drying
Methoxybutropate microencapsulation by gelatin-acacia complex coacervation
No full textMicrocapsules of methoxybutropate solid particles or of an oily saturated solution of the same drug were prepared by complex coacervation between gelatin and acacia and dried with three different methods: isopropanol addition, spray-drying, and freeze-drying. Successively, microparticles were analyzed by infrared thermobalance, ultraviolet (UV) spectroscopy, optical and scanning electron microscopy, and sieves to find out parameters such as yield, moisture content, encapsulation percentage, morphology of solid particles, and particle size. Results highlighted that the most appropriate drying method for industrial purposes was spray-drying, particularly for oil-containing microcapsule formulations.
Read More: http://informahealthcare.com/doi/abs/10.1081/DDC-10010218
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