• 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.

• Journal of Pharmaceutical Investigation
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• v.40 no.5
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• pp.285-289
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• 2010

Manufacturing a multi-layered tablet such as Xatral XL$^{(R)}$ is more complex and expensive than monolayered tablets, but mono-layered tablets may have less favorable release properties depending on the pharmacodynamics and pharmacokinetics of the active ingredient. We therefore sought to develop a monolayer tablet with a similar dissolution profile to the commercial alfuzosin sustained-release triple layered tablet (Xatral XL$^{(R)}$). We prepared four different mono-layered alfuzosin tablets with different concentrations of hydroxypropyl methycellulose and PVP K-90. Fomulation III with alfuzosion/mg-stearate/ HPMC/ PVP K-90 (10/5/110/95 mg/tab) has a similar dissolution rate to Xatral XL$^{(R)}$, with a similarity factor score of 81.4. However, the swelling and erosion rates of the two formulations were different, and NIR analysis showed differences in the mechanisms of drug release. Thus, although formulation III and Xatral XL$^{(R)}$ show similar dissolution rates, the mechanisms of drug release are different.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.759-760
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• 2000

5-fluorouracil loaded chitosan-cellulose microspheres was prepared by W/O/W multiple emulsions solvent evaporation technique which is appropriate to oral drug delivery. The influences of process parameters on the physical characteristics of microspheres and on in vitro drug release were investigated.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.711-712
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• 2005

• Bulletin of the Korean Chemical Society
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• v.25 no.8
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• pp.1257-1260
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• 2004

• Proceedings of the PSK Conference
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• 2003.10a
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• pp.47-49
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• 2003

Development of drug delivery systems has been recognized as one of portfolios to gain a competitive edge in pharmaceutical industry over 30 years. The application of drug delivery technologies offers pharmaceutical companies and patients several therapeutic benefits, including improving efficacy and adverse effect profiles, enhancing patient compliance and potentially regenerating unsuccessful drugs. (omitted)

• Toxicological Research
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• v.17
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• pp.211-216
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• 2001

Drugs can have various adverse effects on the immune system including unintended immun-osuppression, induction of both drug-specific immune responses (including drug allergies) and non-specific immunostimulation (including autoimmune reactions), and direct activation of effector mechanisms (such as histamine release). As a practical matter, the Center for Drug Evaluation (CDER) relies on standard non-clinical toxicology studies to detect unintended immunosuppression. Specific assays using guinea pigs and mice are available to identify drugs that can induce immune-mediated dermal hypersensitivity reactions. Respiratory and systemic hypersensitivity and autoimmune reactions are more difficult to model in non-clinical studies. Unintended nonspecific immunstimulation can be detected in animal studies. CDER is currently developing specific guidance for evaluating potential drug immunotoxicity.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.342.3-343
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• 2002

Non-insulin dependent diabetes mellitus (NIDDM) is characterized by hyperglycemia, hyperinsulinemia. and impaired insulin action. Insulin resistance is considered to be the underlying mechanism in the pathogenesis of type 2 diabetes. which also leads to dyslipidemia, hypertension. and obesity. Thazolidinediones are a class of oral insulin-sensitizing agents that improve glucose utilization without increasing insulin release. They significantly reduce glucose, lipid and insulin levels in rodent models of NIDDM and obesity, and recent clinical data support theri efficacy in obese diabetic patients. (omitted)

• Journal of Pharmaceutical Investigation
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• v.29 no.3
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• pp.185-191
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• 1999

The polymeric films containing drug and various excipients were fabricated using aqueous-based $Eudragit^{\circledR}$ RS 30D dispersions. The diffusional behaviors and mechanism of the fabricated polymeric film were investigated using Keshary-Chien diffusion cell. The melatonin was used as a model drug. The diffusion behaviors of drug through the fabricated polymeric films were highly dependent on drug concentration in donor part, polymer contents and drug concentration, and the types of plasticizers and solubilizers. The fabricated polymeric films containing excipients and solubilizers could be applied for the controlled release of poorly water-soluble drug and for the preparation of drug-containing latex films for topical or oral drug delivery.

• Archives of Pharmacal Research
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• v.22 no.5
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• pp.474-478
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• 1999

Modulation of unscheduled DNA synthesis by dehydroepiandrosterone (DHEA) after exposure to various chemical carcinogens was investigated in the primary rat hepatocytes. Unscheduled DNA synthesis was induced by treatment of such direct acting carcinogens as methly methanesulfonate (MMS) and ethyl methanesulfonate (EMS) or procarcinogens including benzo(a)pyrene (BaP) and 7, 12-dimethylbenz(a)anthracene (DMBA). Unscheduled DNA synthesis was determined by measuring [methyl-3H]thymidine radioactivity incorporated into nuclear DNA of hepatocytes treated with carcinogens in the presence or absence of DHEA. Hydroxyurea $(5{\times}10^{-3} M)$was added to growth medium to selectively suppress normal replication. DHEA at concentrations ranging from $(1{\times}10^{-6} M)$ to$(5{\times}10^{-4} M)$ did not significantly inhibit unscheduled DNA synthesis induced by either MMS $(1{\times}10^{-4} M)$ or EMS $(1{\times}10^{-2} M)$. In contrast, DHEA-significantly inhibited unscheduled DNA synthesis induced by BaP $(6.5{\times}10^{-5} M)$ and DMBA.$(2{\times}10^{-5} M)$. DHEA-induced hepatotoxicity in rats was examined using lactate dehydrogenase (LDH) release as an indicator of cytotoxicity. DHEA exhibit no significant increase in LDH release compared with the control at 18 h. These data suggest that nontoxic concentration of DHEA does not affect the DNA excision repair process, but it probably influence the enzymatic system responsible for the metabolic activation of procarcinogens and thereby decreases the amount of the effective DNA adducts formed by the ultimate reactive carcinogenic species.