• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2451-2458
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• 2010

We prepared sustained release matrix system which contains carvedilol with Compritol 888 ATO used as lipophilic sustained release excipient and hydroxypropyl methyl cellulose (HPMC) or polyethylene oxide (PEO) used as hydrophilic sustained release polymer. Wet granulation compressed method was used for preparing carvedilol sustained release matrix tablets. When carvedilol sustained release matrix tablets were prepared, we evaluated the drug release kinetics which is affected by Compritol 888 ATO ratio, a kind of hydrophilic polymer (HPMC, PEO) and hot melt coating coagglutination (HMCC) process was done. The drug release kinetics was measured for 24 hours in pH 1.2 simulated gastric fluid and pH 6.8 simulated intestinal fluid, using a dissolution tester at $37.5^{\circ}C$ in 50 rpm. Dissolution rate of controlled release matrix tablets of carvedilol was evaluated by paddle method. We confirmed that HMCC process was very effective to controlled release of drugs. The rate of Compritol 888 ATO, as a lipidic material, can control the drug release pattern about the elution rate of 95% and 24 hours delay than that of the normal tablet.

• Journal of Pharmaceutical Investigation
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• v.36 no.4
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• pp.271-276
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• 2006

Felodipine, a calcium-antagonist of dihydropyridine type, is a poorly water soluble drug and has very low bioavailability. As preceding studies, use of solid dispersion systems and surfactants(solubilizers) has been suggested to increase dissolution and to improve bioavailability of felodipine. But in case of solid dispersion systems, large amount of toxic organic solvents should be used and manufacturing process time become longer than conventional process. In case of using surfactants, as time elapsed, decreasing of dissolution rate of felodipine due to crystallization has been reported. In this study, Copovidon as a hydrophilic polymer and $Transcutol^{\circledR}$ as a surfactant were combined to formulations if order to increase dissolution of felodipine and conventional wet granulation process were applied to manufacturing of formulations. The effect of Copovidon and $Transcutol^{\circledR}$ on the dissolution oi felodipine was investigated in-vitro. When Copovidon and $Transcutol^{\circledR}$ used simultaneously, the dissolution rate of felodipine was prominently increased compared with when used separately and the maximum increase in the dissolution of felodipine was 5.8 fold compared to control. This is most probably due to synergy effect by combination of Copovidon and $Transcutol^{\circledR}$. Felodipine sustained release tablets were successfully formulated using several grades of HPMC as a release retarding agent. The stability of felodipine sustained release tablet was evaluated after storage at accelerated condition($40^{\circ}C/75%\;RH$) for 6months in HDPE(High density polyethylene) bottle. Neither significant degradation nor change of dissolution rate for felodipine was observed after 6months. In conclusion, felodipine sustained release tablet was successfully formulated and dissolution of felodipine, poorly water soluble drug, was prominently increased and also stability was guaranteed by using combination system of hydrophilic polymer and surfactant.

• Journal of Pharmaceutical Investigation
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• v.30 no.3
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• pp.179-189
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• 2000

Clebopride malate(Cm) is a new benzamide drug which has a potent central antidopaminergic activity possessing antiemetic and anxiolytic properties. A purpose of this study was to assess the feasibility of formulating sustained release preparation by dispersing a drug in hydrophilic polymeric matrices and double layered tablets(DLT), using HPMC, carbopol, PEO, PVP/VA and other polymers as a rate controlling barrier. The matrix and DLT showed optimum dissolution pattern up to 8 hours and the contents of polymer were optimized at 30% level in this preparation. After an oral administration in beagle dog, Cm concentration was determined by use of GC-ECD and pharmacokinetic parameters were calculated by Vallner's method. The AUC of DLT showed similar results and the duration of action was increased 55% compared to that of regular release dosage form. The calculated absorption rate effectiveness(ARE) and controlled release effectiveness(CRE) for DLT increased 50% compared to that of matrix, the overall effectiveness(E) of this product appears to be about 70%. in vivo effectiveness test, DLT showed significant differences from control on antiemetic action of Cm. In consequence, it was possible to conclude that double layered tablet might be a good candidate for the sustained release dosage forms.

• KSBB Journal
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• v.16 no.5
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• pp.505-510
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• 2001

The preparation, characterization and drug release behaviour of drug(indomethacin) loaded Poly(L-lactic acid)(PLA), tarmarind acetate and levan acetate mircospheres were investigated. Hydrophobic tarmarind acetate and levan acetate were prepared by chemical modification of hydrophilic tarmaried gum and levan and microspheres were made by a solvent evaporation method. In the case of poly(L-lactic acid) microspheres, drug release rate was effected by polymer-drug ratios and drum release was sustained by increasing of polymer content. The yield of microspheres were effected by many factors and the mean size was below 1 $\mu$m, The IND release profiles from tarmarind acetate and levan acetate micropheres were more slightly less than ploy(L-lactic acid) microspheres.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.2
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• pp.165-174
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• 2017

This study reports a synthesis of an amphiphilic linear block copolymer consisting of a hydrophobic poly (lactide) (PLA) block and a hydrophilic hyperbranched polyglycerol (hbPG) block, PLA-b-hbPG. Simple chemical modification of the hbPG block with 4-hydroxycinnamic acid (CA) led to a photo-crosslinkable block copolymer, PLA-b-hbPG-CA. Nanosized micelles of the block copolyemrs were used as drug carriers for sustainable release. The hbPG shell made of a small molecular weight hbPG block showed excellent hydrophilicity, which can minimize in vivo toxicity. The UV-crosslinked PLA-b-hbPG-CA micelles loaded with drugs colud be served as a drug delivery carrier for its biocompatibility and self-assembled structures.