• Journal of Pharmaceutical Investigation
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• v.24 no.3
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• pp.131-137
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• 1994

Drug delivery system by the use of red blood cells was established to sustain the release of drugs in the circulatory system by the intravenous injection. The entrapment method by the preswelling technique was re-examined and evaluated for searching the new entrapping conditions without hemolysis. The addition of 4 volume of $0.6{\times}\;hank's$ balanced salt solution (HBSS) into 1 volume of 50% red blood cells suspension did not induce the hemolysis and change the hematocrit level in this experimental condition (within 15 min). Most of daunorubicin could be entrapped into red blood cells within 15 min. While the intracellular adenosine triphosphate (ATP) level followed by the entrapment was reduced to 86% of normal ATP level, the membrane fluidity and the shape factor of red blood cells were not altered. The release rate of daunorubicin from red blood cells was affected by the hemolysis under this condition. To maintain the intracellular ATP in red blood cells, the new reaction buffer was made With the addition of ATP and sodium pyruvate during the entrapment procedure because the hemolysis during the release test would reflect the loss of intracellular ATP that might result in the decrease of the viability in vivo. The addition of ATP raised the intracellular ATP level, which protect the hemolysis during the release test.

• Polymer(Korea)
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• v.26 no.4
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• pp.535-542
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• 2002

We have prepared the surfactant-free nanoparticles of poly(DL-lactide-co-glycolide) (PLGA) by dialysis method and their physicochemical properties such as particle size and drug contents were investigated against various solvent. The size of PLGA nanoparticles prepared by using dimethylacetamide (DMAc), dimethylformamide (DMF), and dimethylsulfoxide (DMSO) was smaller than that from acetone. Also, the order of drug contents was DMAc>DMF>DMSO=acetone. These phenomena could be expected from the fact that solvent affects the size of nanoparticles and drug contents. The PLGA nanoparticles have a good spherical shapes as observed from scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Also, surfactant-free nanoparticles entrapping norfloxacin (NFx) have a good drug loading capacity without free-drug on the surface of nanoparticles confirmed by the analysis of X-ray powder diffraction. Release kinetics of NFx used as a model drug was governed not only by drug contents but also by particle size. Also, the biodegradation rate of PLGA nanoparticles prepared from DMF was faster than that prepared from acetone, indicating that the biodegradation of PLGA nanoparticles is size-dependent.

• Archives of Pharmacal Research
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• v.3 no.1
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• pp.7-12
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• 1980

Ampliciline was synthesized from 6-amino-pencillanic acid (6-APA) and D-.alpha. phenylglycine methyl ester by using amplicilin synthesizing enzyme from Peudomonas melanogenum (IAM 1655). The whole cell enzyme was immobilized by entrapping it in the polyacrylamide gel lattices. The polymer used in the enzyme entrapment was made from 150 mg per ml of acrylamide monomer and 8 mg per ml of N, N'-methylenebisacrylamide. About 200 mg/whole cell enzyme was mixed in the polymer for entrapment. The maximal activity retention after immobilization was 56%. The optimal pH values for the whole cell enzyme and the immobilized whole cell enzyme were 6.0 and 5.9, respectively. The optimal temperature for the enzyme activity were the same for both type of preparations. The enzyme stabilities against pH and heat increased for immobilized whole cell enzyme. Immobilized cell was more stable especially in the acidic condition while both type were found to be very suceptible to thermal inactivation at a temperature above 4.deg.C. The kinetic constants obtained from Lineweaver-Burk plot based on two substate reaction mechanism showed somewhat higher value for immobilized whole cell enzyme as compared to the whole cell enzyme : the Km value for 6-APA were 7.0 mM and 12.5 mM while Km values for phenylglycine methyl ester were 4.5 mM and 8.2 mM, respectively. Using the immobilized whole cell enzyme packed in a column reactor, the productivity of ampiciline was studied by varying the flow rate of substrate solution. At the space velocity, SV, 0.14 hr$^{-1}$ the conversion was 45%. Operational stability found in terms of half life was 30 hr at SV = 0.2 hr.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.779-784
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• 1995

The effective production of 5'-GMP(5'-Guanylic acid) by immobilized 5'-GMP producing fusant RC102(intergeneric protoplast fusion between Brevibacterium ammoniagenes ATCC21263 and Corynebacterium glutamicum ATCC21171) was investigated. The Fusant RC102 was immobilized by entrapping in -carrageenan, agar, polyacrylamide or Ca-alginate. 3% k-carrageenan was selected as the most suitable matrix. In the production of 5'-GMP using the immobilized whole cells of fusant RC102, the optimum conditions were $32^{\circ}C$, pH 8.0, $30\mu\textrm{g}/L\;of\;Mn^{2+},\;1{\times}10^{-6}%\;of\;Zn^{2+}$. In order to use fermentation medium containing CSL(Corn Steep Liquor) plentiful in $Mn^{2+}$, the optimum conditions of penicillin G, D-cycloserine and POESA(polyoxyethylene stearylamine) for production of 5'-GMP were 0.8unit/ml, 0.8unit/ml, 0.8unit/ml and 5mg/ml, respectively. Cationic surfactant, POESA was effective and superior to the antibiotics, penicillin G or D-cyloserine in 5'-GMP productivity. The condinuous fermentation using immobilized fusant RC102 showed that 5'-GMP productivity was stable for more than 15 days.

• Microbiology and Biotechnology Letters
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• v.14 no.4
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• pp.285-291
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• 1986

Immobilized Candida lipolytica cells were prepared by entrapping the whole cells in calcium alginate gel. To enhance citric acid productivity, immobilized cells were Incubated with activation medium in fluidized-bed reactors. When the activation was done in batch operation, maximum citric acid productivity appeared in a much shorter time than in continuous operation. Activated immobilized cells were enhanced about 10-fold in citric acid production relative to non-activated immobilized cells. The productivity of citric acid was also influenced by bead size. When Immobilized cells were reacted in a fluidized-bed reactor with the same quantity of cells, the citric acid productivity was increased as the bead size was decreased.

• Polymer(Korea)
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• v.28 no.4
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• pp.291-297
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• 2004

Water-soluble chitosan micro spheres were prepared by emulsification of chitosan solution in mineral oil followed by cross linking reaction with different amount of the cross linking agent (glutraraldehyde), different chitosan concentration. Then, the physicochemical properties such as morphological change by degradation, drug loading efficiency, and drug release profiles were investigated with the drug loaded water-soluble chitosan microspheres. Norfloxacin loaded water-soluble chitosan micro spheres showed excellent drug entrapping capacities without burst release caused by surface bound drug. The absence of the surface bound drug also confirmed by X-ray diffraction study. Degradation and drug release studies showed that the amount of the crosslinking agent played a crucial role for drug loading, release and degradation. The water-soluble chitosan micro spheres showed more sustained drug release profiles with slower degradation and larger particle size by increasing crosslinking agent.

• Journal of the Korean Society of Radiology
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• v.82 no.2
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• pp.487-492
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• 2021

Immunoglobulin G4 (IgG4)-related disease is a systemic disease characterized by dense lymphoplasmacytic infiltrates with abundant IgG4-positive plasma cells and fibroblast proliferation. The retroperitoneal involvement of IgG4-related disease usually appears as a soft-tissue mass covering the abdominal aorta or entrapping the ureters, resulting in hydronephrosis. Here, we present a case of IgG4-related disease with retroperitoneal involvement in a 75-yearold woman with an unusual manifestation. A preoperative computed tomography (CT) scan revealed an irregular infiltrative retroperitoneal mass invading the normal anatomic barriers, raising the suspicion of malignancy or inflammation. Contrast-enhanced CT revealed a homogeneous progressive enhancement of the mass.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.446-452
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• 1999

Ectopic eruption of the first permanent molar means the first permanent molar assumes an atypical path of eruption resulting in premature atypical resorption of the second primary molar. If the reversible eruption does not occur, early loss of the second primary molars results in space loss, mesial tipping of the first permanent molar, impaction of the second premolar, buccal segment crowding and overeruption of opposing tooth. The main objectives of treatment are (1) to prevent loss of the second deciduous molars so it can continue to serve as a space maintainer and (2) to regain lost arch length, allowing the second premolar to erupt into normal position. The optimal treatment approach depends on a number of factors including the clinical eruption status of /6/, the change in position of /6/, the amount of enamel ledge of /E/ entrapping /6/, the mobility of /E/, and the presence of pain or infection. Unilateral appliance to correct the mesial angulation of ectopic permanent first molars, as in the majority of the appliance designs, would produce a resultant force that would further enhance the space loss. A bilateral support similar to the holding arch design is recommended to maximize the anchorage. These case reports present the successful result of preserving space for the second premolar in treatment of ectopic eruption of the first permanent molar using Halterman appliance with bilateral anchorage on patients visiting department of pediatric dentistry in Samsung Medical Center.

• Journal of Pharmaceutical Investigation
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• v.26 no.2
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• pp.105-112
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• 1996

The surface of albumin microspheres was modified with methotrexate(MTX) by using 1,3-dicyclohexylcarbodiimide (DCC). Surface-modified albumin microspheres entrapping no MTX (SAMS), free MTX (SAMSF) and MTX-bovine serum albumin(BSA) conjugates(SAMSC) were prepared. The organ-targeting ability of free $[^3H]MTX,\;[^3H]MTX-BSA$ conjugate and the above microspheres was evaluated after i.v. administration of the preparations, equivalent to 150 nCi via the tail vein of mice. The total radioactivity in the lung increased immediately in a few minutes after i.v. injection of the microspheres, and then declined for the period of 3-4 weeks. However, the radioactivity in the liver, spleen and kidney increased slowly during the rapid decrease in radioactivity in the lung. This suggested that the microspheres could be entrapped rapidly in the lung through mechanical filtration because of their large size and slowly redistributed to the liver, spleen and kidney due to either the microspheres being degraded enough for the size to allow passage through the capillary beds of the lung and/or the release of $[^3H]MTX\;or\;[^3H]MTX-BSA$ conjugates from the microspheres. The amount of $60{sim}70%$ of the dose was targeted to the liver after the i.v. injection of SAMS, SAMSF and SAMSC, and the values of $(R_e\;^*\;_{e)liver}$ from the microspheres were $5{\sim}7$ compared to free MTX. This suggested that the liver-targeting ability from surface-modified albumin microspheres could be $5{\sim}7$ times as that of free MTX. The liver-targeted drug was accumulated in the Kupffer cells at the initial stage, thereafter the drug in the Kupffer cell was slowly transferred into the hepatocytes. The value of AUQ for liver from SAMS was higher than that from SAMSF, but much lower than that from SAMSC. This suggest that MTX bound to their surface could be eliminated slower than the entrapped free MTX, and faster than the entrapped MTX-BSA conjugates. This is consistent with the in vitro release rates order in the presence of a proteolytic enzyme. Also, surface-modified MTX was scarcely released in the absence of a proteolytic enzyme. Therefore, the surface-modified MTX nay be released (or eliminated) rapidly from SAMSC at the target site, and thereafter MTX may be released (or eliminated) slowly from the entrapped MTX-BSA conjugates in SAMSC for a long period.

• Analytical Science and Technology
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• v.11 no.5
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• pp.409-412
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• 1998

The analytical method to determine europium(III) ion in aqueous solution by fluorescence spectroscopy based upon the conformational change of calmodulin in the presence of the analyte has been studied. The fiber optic chemical sensor used in this study was constructed by entrapping a fluorescein-labeled calmodulin solution, EGTA, buffer solution at the common end of a bifurcated fiber optic bundle by means of a dialysis membrane. The calibration curve to determine europium(III) ion was obtained when concentration of calmodulin, concentration of EGTA, Tris-HCl buffer solution, pH, excitation wavelength and fluorescence wavelength were $5.0{\times}10^{-5}M$, 0.50 mM, 5.0 mM, 7.0, 495 nm and 520 nm, respectively. The detection limit was $1.0{\times}10^{-11}M$ and the working range of the calibration curve for the sensor was $1.0{\times}10^{-11}M{\sim}1.0{\times}10^{-9}M$. The response time was 15 minutes. For the determination of europium(III) ion by the present method, $Na^+$ and $K^+$ ions did not interfere but $Ca^{2+}$ ion seriously interfered.