• Macromolecular Research
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• v.17 no.7
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• pp.464-468
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• 2009

Gelatin nanoparticles derived from bovine or porcine have been developed as various types of drug delivery system, and they need to be cross-linked to maintain their physicochemical properties in aqueous environments. Although gelatin is a widely used material in pharmaceutical industries, the safety issue of animal-origin gelatins, such as transmissible mad cow disease and anaphylaxis, remains to be solved. The purpose of this study was to prepare type A gelatin (GA) nanoparticles by modified, two-step, desolvation method and compare the toxicity of the resulting GA nanoparticles with recombinant human gelatin (rHG) nanoparticles. The GA nanoparticles were characterized, and drug loading and release pattern were measured. FITC-BSA, a model protein, was efficiently loaded in the nanoparticles and then released in a biphasic and sustained release pattern without an initial burst. In particular, the cell viability of the GA nanoparticles was less than that of the rHG nanoparticles. This finding suggests that rHG nanoparticles should be considered as an alternative to animal-origin gelatin nanoparticles in order to minimize the safety problems.

• Macromolecular Research
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• v.16 no.5
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• pp.418-423
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• 2008

Poly[(R)-3-hydroxy butyrate] (PHB) and methoxy poly(ethylene glycol) (mPEG) were conjugated by the transesterification reaction with tin(II)-ethylhexanoate (Sn(Oct)-II) as a catalyst. Hydrophobic PHB and hydrophilic mPEG formed an amphiphilic block copolymer which was formed with the self-assembled polymeric micelle in aqueous solution. In this study, we tried to determine the optimum ratio of hydrophobic/hydrophilic segments for controlled drug delivery. The particle size and shape of the polymeric micelle were measured by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Their size were 61-102 nm with various block ratios. Griseofulvin was loaded in the polymeric micelle as a hydrophobic model drug. The loading efficiency and release profile were measured by high performance liquid chromatography (HPLC). The model drug in our system was constantly released for 48 h.

• YAKHAK HOEJI
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• v.18 no.1
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• pp.49-58
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• 1974

Tablet product design problem was structured as constrained optimization problem and subsequently solved by multiple regression analysis and Lagrangian method of optimization. Aluminum flufenamate was the drug chosen and microcrystalline cellulose nad starch were the binder and disintegrant, respectivley. The effect of the binder and disintegrant concentration on tablet hardness, friability, volume, in vitro release rate, and urinary excretion rate of drug in human subjects was recorded. Since a reasonably rapid release rate of drug is generally an important objective in the design of solid dosage form, optimization of this parameter was employed in studying the applicability of constrained optimization to a pharmaceutical product design problem. In addition to finding optimal sitivity analysis studies to such problems was also illustratd. It would appear that prediction of the in vivo t$_{50%}$ response from a knowledge of the incitro t$_{50%}$ response can be made fairly accurately for the tablet system used in this study.

• Macromolecular Research
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• v.10 no.5
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• pp.246-252
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• 2002

In order to the development of the delivery device of long-acting local anesthetics for postoperative analgesia and control of chronic pain of cancer patient, fentnyl-loaded poly (L-lactide-co-glycolido) (PLGA, molecular weight, 5,000 g/mole; 50 : 50 mole ratio by lactide to glycolide) microspheres (FMS) were studied. FMS were prepared by an emulsion solvent-evaporation method. The influence of several preparation parameters such as initial drug loading, PLGA concentration, emulsifier concentration, oil phase volume, and fabrication temperature has been investigated on the fentanyl release profiles. Generally, the drug showed the biphasic release patterns, with an initial diffusion followed by a lag period before the onset of the degradation phase, but there was no lag time in our system. Fentanyl was slowly released from FMS over 10 days in vitro with a quasi-zero order property. The release rate increased with increasing drug loading as well as decreasing polymer concentration with relatively small initial burst effect. From the results, FMS may be a good formulation to deliver the anesthetic for the treatment of chronic pain.

• Journal of Pharmaceutical Investigation
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• v.32 no.4
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• pp.299-303
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• 2002

The oral bioavailability of itraconazole is variable and low in fasting state. This is mainly due to the low solubility of this drug. Bioavailability can be improved by changing the formulation and it is general that the liquid preparations show greater bioavailability than the solid dosage forms such as tablets and capsules do. Benzyl alcohol-water binary mixture showed the excellent solubilizing capacity for itraconazole but the release of the drug from the preparation needs to be enhanced. In this study, various nonionic surfactants and hydrophilic polymers, poloxamers, were screened to investigate their effects on the releasε of itraconazole from the liquid preparations. Poloxamer 407 showed the most enhancing effect on the drug release and the release rate was proportional to thε amount of poloxamer 407 added. A liquid preparation of itraconazole, consisting of benzyl alcohol/water/poloxamer 407 ternary solvent system, releasεd more than 80% of the total drug amount at 5 min and showεd the possibility of a new formulation development.

• 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.

• Composites Research
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• v.21 no.3
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• pp.18-23
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• 2008

The Rapid Prototyping (RP) technology has advanced in many application areas. In this research, implantable Drug Delivery System (DDS) was fabricated by an RP system, Nano Composite Deposition System (NCDS). The DDS composite consists of 5-fluorouracil (5-FU), as drug particles, and PLGA85/15 as biodegradable polymer matrix. To have larger surface area, the DDS was fabricated in a scaffold shape, and its degradation was tested in vitro environment. Biocompatible Hydroxyapatite (HA) powders were added to the drug-polymer composite in order to control drug release. Test results showed a possibility of controlled release of scaffold DDS over 50 days.

• Membrane Journal
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• v.17 no.1
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• pp.67-79
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• 2007

Uniform microcapsules containing ionic model drugs were prepared by controlling various conditions of emulsification procedure using a lab-scale membrane emulsification system with a SPG (Shirasu porous glass) tubular membrane. We observed the effects of various emulsification parameters [concentration and molecular weight of polycaprolatone (PCL) polymer, transmembrane pressure and emulsifier concentration in disperse phase and continuous phase, stirring speed] on the mean size and size ditribution of microcapsules containing lidocaine hydrochloride (cationic drug), sodium salicylate (nonionic drug) and 4-acetaminophen (anionic drug) used as a model drugs. Also, release characteristics of a model drugs from PCL microcapsules were investigated. Controlling membrane emulsification parameters, uniform PCL microcapsules with about $5\;{\mu}m$ of the mean size were finally prepared. The release rate and the burst effect of microcapsules were decreased in condition of the acidic solution, but it was increased in condition of the base solution.

• Biomedical Science Letters
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• v.12 no.4
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• pp.443-450
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• 2006

To demonstrate their possibilities as an enhanced vaccine delivery system, protein-loaded Poly lactide glycolide copolymer (PLGA) microspheres were prepared with different physical characteristics. Ethyl acetate (EA) solvent extraction process was employed to prepare microspheres and the effects of process parameters on drug release properties were evaluated. The biodeuadability of microspheres was also evaluated by the pH change and GPC (Gel permeation chromatography). Primary IgG antibody responses in BALB/c mice were compared with protein saline solutions as negative controls and adsorbed alum suspensions as positive controls after single subcutaneous injection for in vivo studies. The microspheres showed a erosion with a highly porous structure and did not keep their spherical shape at 45 days and this result could be confirmed by GPC. In vitro release of proteinous drug showed initial burst effect in all batches of microspheres, followed by gradual release over the next 4 weeks. PLGA microspheres were degraded until 45 days and the secondary structure of OVA was not affected by the preparation method. Enzyme-linked immunosorbent assays demonstrated that the single subcutaneous administrations of OVA-loaded PLGA microspheres induced enhanced serum IgG antibody response in comparison to negative and positive controls. These results demonstrated that microspheres providing the controlled release of antigens might be useful in advanced vaccine formulations for the parenteral carrier system.

• Polymer(Korea)
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• v.33 no.3
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• pp.219-223
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• 2009

The nanofibers fabricated by using an electrohydrodynamic process has been used as various applications, such as nano-device, filtering system, protective clothes, wound dressing, and drug delivery system (DDS). Of these applications, the DDS should be needed to minimize side effects of drugs, maximize the properties of medicine, and efficiently deliver the required amount of drugs to the diseased area. In this paper, by using the electro spinning process, which is one of electrohydrodynamic processes, two different types, polycarprolactone and poly(ethylene oxide)/Rhodamine B, of electrospun mats were fabricated layer by layer and the release behavior of Rhodamine B was characterized with time. In addition, to show the feasibility of DDS of this type, we tested release behavior of a peptide of the nanofiber system, a PCL/(Peptide+PEO)/PCL nanofiber mat. The released peptide did not loss biological activities. From these results, we believe that the layered nanofiber mat as a DDS has enough function of a new drug delivery system.