• YAKHAK HOEJI
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• v.57 no.6
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• pp.442-447
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• 2013

The aim of the present study was to improve commercial twice-a-day Acebrophylline formulation to once-a-day new formulation to improve patient compliances. To develop the double-layered tablet, the sustained release layer was prepared using Eudragit$^{(R)}$ L100-55 and Carnauba wax. The sustained release layer has shown delayed release rates in pH 1.2 which comparable to that of performed in pH 6.8 buffer. In the comparative pharmacokinetic study with commercialized Surfolase$^{(R)}$, the present double-layered Acebrophylline tablet has shown similar pharmacokinetic parameters of AUC, $C_{max}$ and $T_{max}$ values.

• 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).

• Journal of Pharmaceutical Investigation
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• v.23 no.4
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• pp.213-216
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• 1993

${\kappa}-Carrageenan$, an anionic polysaccharide, was employed in tablet formulations and its function as a drug release sustaining agent was investigated. Tablets composed of ${\kappa}-carrageenan$ and hydroxypropyl methylcellulose were fabricated by using direct compression method. Lactose and sodium alginate were utilized as controls for ${\kappa}-carrageenan$. Drug release experiments performed at pHs 1.2 and 7.4 revealed that ${\kappa}-carrageenan$ retains pH-dependent sustained release effects due to its anionic characteristics. Also, the ionic interaction between ${\kappa}-carrageenan$ and drugs exerted significant affects on drug release kinetics. ${\kappa}-Carrageenan$ was found out to be a useful additive for sustained release tablet formulations.

• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.323-329
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• 1997

Ipriflavone is non-hormonal antiosteoporotic drug which inhibits bone resorption by reducing recruitment and/or differentiation of osteoclasts, and stimulates proliferation and differentiation of osteoblast, and also enhances calcitonin secretion in the presence of estrogen. Although some kinds of immediately-released preparation of ipriflavone are available in commercial market, in present study, we tried to formulate sustained-release tablet using coating method with hydrophobic and hydrophilic coating materials. In vitro dissolution test was applied to evaluate sustained-release patterns of several test preparations (Test tablet A, B and C) designed using different preparation method or different compositions. From the results of dissolution test, test tablet A which showed suitable dissolution profile was selected as the candidate of new product. Pharmacokinetic evaluation of test drug, ipriflavone sustained-release tablets, was conducted in 6 beagle dogs weighing $11.5{\pm}0.5\;Kg$ compared with $Theobon^{\circledR}$ tablet, immediately-released tablet (Kukjae Pharm. Co.) as reference drug. Two products were randomly administered to 6 beagle dogs, and after 1 week, cross-over study was conducted. From the present study, AUC and $T_{max}$ of test product were significantly different from those of reference product (p<0.05), respectively$(AUC\;:\;3646.28{\pm}472.56\;vs\;3646.28{\pm}472.56\;ng{\cdot}hr/ml,\;T_{max}\;:\;4.33{\pm}1.03\;vs\;1.42{\pm}0.38\;hr)$. But $C_{max}$ was not significantly different between two products (p>0.05) $(\;512.52{\pm}48.18\;vs\;443.97{\pm}140.53\;ng/ml)$. From the results of pharmacokinetic evaluations, it was noted that absorption amount of test product was increased, but absorption rate was delayed and $C_{max}$ of two products were not changed. And it was concluded that redesign of the sustained-release preparation which has a lower content of iprifavone rather than test tablet A must be considered.

• Journal of Pharmaceutical Investigation
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• v.37 no.2
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• pp.101-106
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• 2007

Venlafaxine, 1-[2-(dimethylamino)-1-(4-methoxyphenyl)ethyl] cyclohexanol hydrochloride is a novel, nontricyclic antidepressant. venlafaxine is a unique antidepressant that differs structurally from other currently available. The aim ot the study was to formulate sustained-release venlafaxine granules and assess their formulation variables. It consists of two layers, venlafaxine drug layer and sustained release coating layer and manufactured by fluidized bed process. The sustained release of drug could be increased by double-control rising various components in venlafaxine drug layer and sustained-release layer. The drug-containing granules were coated with cellulose acetate, cetyl alcohol and Eudragit RS along with plastisizer such as dibuthyl sebacate as an nano-pore former The release oi venlafaxine depended on the type of Eudragit such as RS, and RL used in the formulation of controlled release layer. These results obtained clearly suggest that the sustained release oral delivery system for venlafaxine could be designed with satisfying drug release profile approved.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.5
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• pp.269-273
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• 2005

In horizontal cells (HCs) that were freshly dissociated from goldfish retina, two types of voltagedependent calcium currents ($I_{Ca}$) were recorded using a patch-clamping configuration: a transient type current and a sustained type current. The cell was held at -40 mV, and the prepulse step of -90 mV was applied before command pulse between -65 and +55 mV. The transient $Ca^{2+}$ current was activated by depolarization to around -50 mV from a prepulse voltage of -90 mV lasting at least 400 ms and reached a maximal value near -25 mV. On the other hand, the sustained $Ca^{2+}$ current was induced by pre-inactivation for less than 10 ms duration. Its activation started near -10 mV and peaked at +20 mV. $Co^{2+}$ (2 mM) suppressed both of these two components, but nifedipine ($20{\mu}M$), L-type $Ca^{2+}$ channel antagonist, blocked only the sustained current. Based on the activation voltage and the pharmacolog$I_{Ca}$l specificity, the sustained current appears to be similar to L-type $I_{Ca}$ and the transient type to T-type $I_{Ca}$. This study is the first to confirm that transient type $I_{Ca}$ together with the sustained one is present in HCs dissociated from goldfish retina.

• Journal of Pharmaceutical Investigation
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• v.36 no.1
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• pp.39-44
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• 2006

Tamsulosin or a salt thereof such as its hydrochloride salt has been known to have an adrenaline ${\alpha}$ receptor blocking action for urethra and prostate areas. It has been widely used as a drug which lowers the prostate pressure and improves urinary disturbance accompanied by prostate-grand enlargement, thus for the treatment of prostatic hyperplasia. To avoid dose-dependent side effects of tamsulosin upon oral administration, the development of sustained-release delivery system is essentially required, that can maintain therapeutic drug levels for a longer period of time. The aim of this study was therefore to formulate sustained-release tamsulosin granules and assess their formulation variables. We designed entric coated sustained-release tamsulosin granules for this purpose. Nano-pores in the outer controlled release membrane were needed in order to obtain initial tamsulosin release even in an acidic environment such as gastric region. In our sustained release osmotic granule system, hydroxypropylmethylcellulose in a drug-containing layer was used as a rate controller. The drug-containing granules were coated with hydroxypropylmethylcellulose phthalate (HPMCP) and Eudragit, along with glycerol triacetate as an aqueous nano-pore former. The release of tamsulosin depended heavily on the type of Eudragit such as RS, RL, NE 30D, used in the formulation of controlled release layer. These results obtained clearly suggest that the sustained-release oral delivery system for tamsulosin could be designed with satisfying drug release profile approved by the Korean Food and Drug Administration.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.7
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• pp.957-963
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• 2007

In this paper, Nonlinear Autoregressive (NAR) method based on Least Square-Support Vector Regression (LS-SVR) is introduced and tested for nonlinear sustained vowel modeling. In the database of total 43 sustained vowel of Benign Vocal Fold Lesions having aperiodic waveform, this nonlinear synthesizer near perfectly reproduced chaotic sustained vowels, and also conserved the naturalness of sound such as jitter, compared to Linear Predictive Coding does not keep these naturalness. However, the results of some phonation are quite different from the original sounds. These results are assumed that single-band model can not afford to control and decompose the high frequency components. Therefore multi-band model with wavelet filterbank is adopted for substituting single band model. As a results, multi-band model results in improved stability. Finally, nonlinear sustained vowel modeling using NAR based on LS-SVR can successfully reconstruct synthesized sounds nearly similar to original voiced sounds.

• Journal of Pharmaceutical Investigation
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• v.30 no.4
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• pp.241-246
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• 2000

To develop a sustained-release preparation containing ketorolac tromethamine, two sustained-release pellet formulations were evaluated with a pharmacokinetic study as compared with a conventional commercial tablets (10 mg $Tarasyn^{TM}$, Roche Korea Ltd.). Two sustained-release formulations were as follows; formulation A was composed of an inner layer containing 75% of drug coated with $Eudragit^{TM}$ RS 100 membrane and an outer layer containing 25% of drug mixed with $Eudragit^{TM}$ NE30D, and formulation B was composed of only an inner layer containing 100% of drug coated with $Eudragit^{TM}$ RS 100 membrane. The dissolution test was performed for two formulations. In case of conventional tablets, 2.5 mg of drug per a dose was administered orally into male Albino rabbit (2.0-2.3 kg of body weight) 3 times at intervals of 4 hours. In case of two sustained formulations, 7.5 mg of drug was administered once orally. Blood samples were withdrawn periodically after the administration, and the blood concentration was determined by HPLC. The conventional tablets showed very high peak-trough fluctuation between administered doses, but two sustained formulations showed less fluctuation. Formulation A with the loading dose showed the time to reach minimum effective concentration (MEC) i.e. the onset time was less than 20 min, while Formulation B had more than 1 hr of the onset time. Formulation A had the more constant plasma level than formulation B. However, formulation B had a time lag, so the plasma level was less than MEC for an initial period of 1 hr. In formulation A, the plasma level was maintained within the therapeutic window $(0.3-5\;{\mu}g/ml)$ for a long period. Formulation A was thought to be an ideal sustained-release formulation for ketorolac tromethamine oral delivery system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.919-920
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• 2010