• Journal of Pharmaceutical Investigation
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• v.19 no.2
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• pp.63-69
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• 1989

Dissolution characteristics of indomethacin (IMC) from hydrophobic polymer solid dispersions were investigated. IMC-polyvinyl chloride (PVC) and IMC-ethylcellulose (EC) solid dispersions were prepared. The dissolution patterns of pure IMC, IMC-PVC and IMC-EC solid dispersions prepared at various ratios (1:1, 1:3, 1:5, 1:9 and 1:19 w/w), and those of corresponding physical mixtures were compared. It was found that the dissolution rates of IMC from solid dispersions with PVC or EC decreased in the order of 1:1>1:3>1:5>1:9>1:19 as the drug to polymer ratios decreased. Also the dissolution rates of IMC from EC solid dispersions increased according to flow rate, but PVC solid dispersions were not affected significantly. After all, PVC and EC matrices could be applied in sustained-release preparation of IMC.

• Archives of Pharmacal Research
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• v.5 no.2
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• pp.61-70
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• 1982

Sulfisoxazole, a chemotherapeutic agent, was microencapsulated with ethylcellulose by means of phase separation form cyclohexane by temperatture change. The size distribution was determined by use of standard sieves and the effect of core to wall ratio was noted. To examine their shapes and usrface characteristics, the microcapsules were observed with a scanning electron microscope. Release of the drug from microcapsules into pH 7.5 buffer medium was studied. The release pattern was found to have similar properties to the release of a drug from an insoluble porous matrix reported. The apparent diffusion coefficient of sulfisoxazole was measured for the transport of the drug from the core of microcapsules into the surronding sink condition. The apparent diffusion coefficient increased with increasing capsule size.

• YAKHAK HOEJI
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• v.42 no.2
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• pp.187-195
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• 1998

In order to ameliorate disadvantages of buccal ointments and mucoadhesive tablets used for the treatment of aphthosis, a thin mucoadhesive patch containing triamcinolone acetoni de was designed and evaluated for the pharmaceutical properties. The adhesive gel layer consisting of Noveon AA-1, hydroxypropylcellulose-M and ethylcellulose N 100, and the protective gel layer of ethylcellulose N 100, Eudragit RSPO and castor oil have been formulated and various properties such as viscosity of drug gel layer, thickness, in vitro adhesion time, adhesive strength, surface pH, content uniformity and drug release are tested. The mean viscosity of drug-containing gel layer was found to increase with increasing amount of Noveon OAA-1 or hydroxypropylcellulose-M. The optimum formulation showed the thickness of 171 ${\mu}$m, surface pH of 4.6, in vitro adhesion time of 8 hours and adhesive strength of 272.7g/sheet. The drug content of each patch was relatively homogeneous with the value of 273${\pm}$6.77g. Drug release study showed that compared to mucoadhesive tablet, the patch showed a faster drug release. Drug release was delayed by hydroxypropylcellulose-M, but not by ethylcellulose N 100. The patches prepared were nonirritant and the muco adhesion was better than the commercial product (AftachR) on the market. Based on these results, this mucoadhesive patch is expected to be an effective dosage form for the treatment of aphthosis.

• Membrane Journal
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• v.13 no.3
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• pp.200-209
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• 2003

Polymer-metal complexed membranes were prepared by solvent evaporation method using ethylcellulose, platinum(II)acetylacetonate, and rhodium(III)acetylacetonate. The various composition of metal salt(0.3-4.0 wt%) were employed to obtain the optimum performance of final membrane. EC-metal complexed membranes were characterized by FTIR and scanning electron microscopy(SEM) to observe the morphology and the performance of oxygen, nitrogen, carbon dioxide, and methane gases was tested. It was shown that the metal salts enhanced the permeability of all gases without decrease of selectivity. However, it was found that Pt had more effects on the permeability of oxygen and nitrogen gases while Rh had more effects on the permeability of carbon dioxide and methane gases. EC-Pt complexed membrane(Pt 1.0 wt%) even showed the enhanced selectivity of oxygen/nitrogen(37%) due to the affinity characteristic of Pt to oxygen.

• Journal of Pharmaceutical Investigation
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• v.20 no.2
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• pp.89-95
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• 1990

Ethylcellulose-PEG 4000 film coated on core tablets was investigated as a potential drug delivery system for the controlled release of chlorpheniramine maleate (CPM). The kinetic analysis of the release data indicated that CPM release followed a diffusion-controlled model, where the quantity released per unit area is proportional to the square root of time. The effect of the film composition, CPM concentration, plasticizer concentration and CPM solubility on the release characteristics were examined. The release rate constant increased as CPM concentration increased. It also increased as the PEG 4000 content in the film increased above 10%(w/w), however, it decreased as the PEG 4000 content increased in the concentration range below 10%(w/w). The release rate constant was not affected by the coated weight on the core tablet. The film-coated tablets which contain CPM only in the coated film layer seemed to be a potential oral drug delivery system for the controlled release of CPM.

• Journal of Pharmaceutical Investigation
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• v.41 no.2
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• pp.67-73
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• 2011

Ion exchange resins can be one of the good carriers for sustained drug release. However, the sustained release may not be enough only with themselves and hence film coating with rate controlling polymers can be applied to have a further effect on the drug release. Due to the environmental and economic issues of organic solvent for the polymer coating, aqueous polymeric systems were selected to develop dosage forms. Among the many aqueous polymeric dispersions for the film coating, EC (ethylcellulose) based polymers such as Aquacoat$^{(R)}$ ECD and Surelease$^{(R)}$ were evaluated.A fluid-bed coating was applied as a processing method. The drug release rate was quite dependent on the coating level so the release rate could be modified easily by changing different levels of the coating. The drug release rate in the Aquacoat$^{(R)}$ coated resin particles was strongly dependent on curing, which is a thermal treatment to make homogeneous films and circumvent drug release changes during storage. After dissolution test using the compressed tablets in which the coated resin particles are contained, inhomogeneous coating and even pores could be observed showing that the mechanical properties of EC were not resistant to granulation and compaction process. However, when tablets were prepared in different batches, the release profiles were almost identical showing the feasibility of the coated resin particle as incorporated into the tablet formulation.

• Journal of Pharmaceutical Investigation
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• v.37 no.6
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• pp.355-358
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• 2007

To develop a sustained-release tablet which had the similar dissolution to commercial ibudilast-loaded sustained-release capsule, the tablets were prepared using hydroxypropylmethylcellulose phthalate (HPMCP), ethylcellulose (EC) and hydroxypropylcellulose (HPC), and dissolution test were carried out with paddle method in KP. The tablet prepared only with HPMCP and EC showed sno similar dissolution pattern to the commercial product. As the ratio of HPMCP/HPC in tablet decreased, the dissolution rate of drug decreased in pH 1.2 but increased in pH 6.8. Furthermore, an ibudilast-loaded sustained-release tablet composed of [ibudilast/EC/HPMCP/HPC (10/10/170/10 mg/tab)] gave similar dissolution to commercial product in pH 1.2 for 3 h and in pH 6.8 for 10 h. Thus, it could be a potential candidate for the substitute of commercial capsule.

• Korean Journal of Clinical Pharmacy
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• v.1 no.1
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• pp.23-30
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• 1991

The sustained-release beads containing terbutaline sulfate (TBS) were prepared by rotogranulation method. The drug was dusted on the non-pareil seeds in a CF-granulator. The sustained-release beads were obtained by coating the active beads with ethylcellulose or $Eudragits^{(R)}$, using in any case the same granulator employed for active beads preparation. The release characteristics of sustained-release beads were examined in vitro by rotating basket method applied to $Bricanyl^{(R)}$ durules which is a sustained-release TBS matrix tablet. The release of terbutaline from the beads in vitro was first-order, and the release rate was dependent on both the coat weight ratio and membrane hydrophilicity. Both surfaces of the beads before and after dissolution were smooth. The drug release pattern from the beads could be thought the diffusion through the polymer membrane. The release rate and the surface of the beads stored for 3 years at room temperature were the same with those of the initial beads.

• Journal of Pharmaceutical Investigation
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• v.27 no.3
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• pp.213-217
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• 1997

The present sustained-release terfenadine-pseudoephedrine HCl dosage form was the core tablet composed of outer (fast-release) layer containing 60 mg of terfenadine and l0mg of pseudoephedrine HCl, and inner (sustained-release) layer containing 110 mg of pseudoephedrine HCl. The purpose of this study was to investigate the possibility of formulating the terfenadine-pseudoephedrine HCl double-layered tablet which was bioequivalent to the core tablet. Its sustained-release and fast-release layer were formulated with disintegrating agents and polymers, respectively, varying with their kinds and amounts. The comparative dissolution test of double-layered and core tablet was carried out at pH 1.2, 4.0 and 6.8, leading to select composite of double-layered tablet whose dissolution pattern was similar to that of core tablet. It was composed of fast-release layer containing 60mg of terfenadine. 10 mg of pseudoephedrine HCl, sodium bicarbonate, microcrystalline cellulose and sodium starch glycolate, and sustained-release layer containing 110 mg of pseudoephedrine HCl and ethylcellulose/hydroxypropyl methylcellulose) (110/30 mg/tablet).

• Textile Coloration and Finishing
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• v.7 no.4
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• pp.97-104
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• 1995

The photochromic dyes(spiroxazine) as a susceptible material were synthesized by condensing 1-nitroso-$\beta$-naphthol with piperidine. The melting point of the synthesized spiroxazine dye was 245$^{\circ}C$. Irradiation with ultraviolet light had effect on reversible coloration reaction. The photochromic dye microcapsules were produced by interfacial precipitation method using polyvinylalcohol and ethylcellulose. The average diameter of microcapsules was 5.4$\mu$m. The dyeability and fastness of dyeings of the microcapsule fibers were increased by pretreatment of the cationic agent.