• Journal of Pharmaceutical Investigation
• /
• v.22 no.4
• /
• pp.267-279
• /
• 1992

Microencapsulations of amoxicillin and cephalexin, using Eudragit RS, RL, E, S and L were investigated. The microcapsules were prepared by the solvent evaporation process in liquid paraffin phase, which is based on dispersion of acetone/isopropanol containing the drug in liquid paraffin. Aluminium tristearate was used as an additive for the preparation of microcapsules. The size distribution, dissolution test and observation by SEM were examined. Good reproducibility in microcapsule preparation was observed. The microcapsules obtained were spherical and free-flowing particles. The dissolution rates of amoxicillin and cephalexin from the microcapsules were considerably decreased as compared with those from amoxicillin and cephalexin powder, respectively. As the dispersing agents (aluminium tristearate) increased, the particle size of microcapsules decreased and the dissolution rate increased. In order to control the release rate of drugs, microcapsules were prepared by mixing Eudragit RS/RL or Eudragit S/L. As Eudragit RL ratio in microcapsule of Eudragit RS/RL increased, the dissolution rate increased. As Eudragit L ratio in microcapsule of Eudragit S/L increased, the dissolution rate increased. Furthermore, the release rates of drugs from Eudragit RS/L or RS/polyelthylene glycol 1540 (PEG 1540) were examined. The dissolution rate of drugs increased with increasing of Eudragit L or PEG 1540 ratio. In conclusion, the release rates of drugs from Eudragit RS/RL or RS/PEG 1540 microcapsule could be controlled, and these microcapsules will be convenient for reducing frequency of administration.

• The Korean Journal of Physiology and Pharmacology
• /
• v.11 no.2
• /
• pp.45-55
• /
• 2007

We elucidated the effects of various components of ischemic medium on the outcome of simulated ischemia-reperfusion injury. Hypoxia for up to 12 hours induced neither apoptotic bodies nor LDH release. However, reoxygenation after 6 or 12 hours of hypoxia resulted in a marked LDH release along with morphological changes compatible with oncotic cell death. H9c2 cells were then subjected to 6 hours of simulated ischemia by exposing them to modified hypoxic glucose-free Krebs-Henseleit buffer. Lowered pH (pH 6.4) of simulated-ischemic buffer resulted in the generation of apoptotic bodies during ischemia, with no concomitant LDH release. The degree of reperfusion-induced LDH release was not affected by the pH of ischemic buffer. Removal of sodium bicarbonate from the simulated ischemic buffer markedly increased cellular damages during both the simulated ischemia and reperfusion. Addition of lactate to the simulated ischemic buffer increased apoptotic cell death during the simulated ischemia. Most importantly, concomitant acidosis and high lactate concentration in ischemic buffer augmented the reperfusion-induced oncotic cell death. These results confirmed the influences of acidosis, bicarbonate deprivation and lactate on the progression and outcome of the simulated ischemia-reperfusion, and also demonstrated that concomitant acidosis and high lactate concentration in simulated ischemic buffer contribute to the development of reperfusion injury.

• The Korean Journal of Physiology and Pharmacology
• /
• v.3 no.2
• /
• pp.199-205
• /
• 1999

Vibrio vulnificus cytolysin caused platelet cytolysis and increased intracellular calcium concentration $([Ca^{2+}]_i)$ of rat platelets in a concentration-dependent manner. In the presence of V. vulnificus cytolysin (3 HU/ml), lactate dehydrogenase (LDH) activity was increased from $1.3{\pm}0.4%$ of control to $64.3{\pm}3.4%$ in platelet suspension buffer. In $Ca^{2+}-free$ platelet suspension buffer, however, V. vulnificus cytolysin did not induce $[Ca^{2+}]_i$ increase and LDH release. Addition of EGTA (2 mM) to suspension buffer after the initial $Ca^{2+}$ influx reversed $[Ca^{2+}]_i$ to the control level. However, a $Ca^{2+}$ channel blocker verapamil $(20\;{\mu}M)$ or mefenamic acid $(20\;{\mu}M)$ did not inhibit V. vulnificus cytolysin-induced $[Ca^{2+}]_i$ increase and LDH release. Divalent cations such as $Co^{2+},\;Cd^{2+}\;or\;Mn^{2+}$ (2 mM each) also did not alter V. vulnificus cytolysin-induced $[Ca^{2+}]_i$ increase and LDH release. V. vulnificus cytolysin (3 HU/ml)-induced calcium influx was completely blocked by lanthanum (2 mM). Lanthanum (2 mM) also completely blocked V. vulnificus cytolysin (3 HU/ml)-induced LDH release. Osmotic protectants such as, raffinose, sucrose or PEG600 (50 mM each) did not inhibit the lytic activity of V. vulnificus cytolysin. In conclusion, lanthanum sensitive $Ca^{2+}$ influx plays a significant role in Vibrio vulnificus cytolysin-induced platelet cytolysis and thrombocytopenia in V. vulnificus infection.

• The Journal of Korean Medicine
• /
• v.17 no.1 s.31
• /
• pp.9-20
• /
• 1996

Oxygen free radicals can generated during metabolic processes in normal cells and by exposure of cells to toxic substances. These radicals have been recogenized to playa critical role in several pathological conditions including carcinogenesis and aging, and they have been implicated in pathogenesis of various diseases such as seizure, Alzheimer's disease, Parkinson's disease, myocardial infarction, respiratory distress syndrome, and rheumatoid arthritis. This study was undertaken to determine if Juglandis semen herb-acupuncture solution (JSHAS) has a protective effect against cell injury caused by oxidants, t-butylhydroperoxide (t-BHP) and $H_{2}O_2$. Cell injury was estimated by measuring lactate dehydrogenase (LDH) release and lipid perexidation was estimated by measurimg malondialdehyde, a product of lipid peroxidation. JSHAS significantly prevented LDH release induced by t-BHP or $H_{2}O_2$ in a dose-dependent manner at concentrations of 0.5-10%. Such protective effect was observed in control tissues untreated with oxidants. JSHAS, at 5% concentration, significantly reduced LDH release even when the concentrations of t-BHP and $H_{2}O_2$ increased to 5 and 200 mM, respectively. JSHAS, at 5% concentration, significantly reduced the lipid peroxidation by t-BHP and $H_{2}O_2$. These results indicate that JSHAS prevents cell injury and lipid peroxidation induced by oxidants in rabbit kidney cells. However, the underlying mechanisms remain to determined.

• YAKHAK HOEJI
• /
• v.43 no.6
• /
• pp.809-817
• /
• 1999

The effect of 2-(4-cyanophenyl)amino-1,4-naphthalenedione-3-pyridinium perchlorate (PQ5) on pla-telet aggregation and its action mechanisms were investigated with rat platelet. PQ5 inhibited the platelet aggregation induced by collagen ($6{\;}{\mu\textrm{g}}/ml$), thrombin (0.4 U/ml) and A23187 ($3{\mu}M$) in concentration-dependent manner with $IC_{50}$ values of 5.50, 25.89 and $37.12{\;}{\mu}M$, respectively. PQ5 also significantly reduced the thromboxane $A_2$ (TXA2) formation in a concentration dependent manner. The collagen-induced arachidonic acid (AA) release in [-3H]-AA incorporated platelet, an indication of the phospholipase $A_2$ activity, was decreased by PQ5 pretreatment PQ5 significantly inhibited the activity of thormboxane synthase only at high concentration ($100{\mu}M$), but did not affect the cyclooxygenase activity at all. Collagen-induced ATP release was significantly reduced by PQ5. Calcium-induced platelet aggregation experiment suggests that the elevation of intracellular free $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) by collagen stimulation is decreased by the pretreatment of PQ5, which is due to the inhibition of calcium release from intracellular store and influx from outside of the cell. PQ5 did not showed the effect of anticoagulation as prothrombin time (PT) or activated partial thromboplastin time (APTT). Form these results, it is suggested that PQ5 exerts its antiplatelet activity through the inhibition of the intracellular $Ca^{2+}$ mobilization and the decrease of the $TXA_2$ synthesis.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7838-7843
• /
• 2015

In this study, metformin hydrochloride for first choice of type 2 diabetes patient is administered relatively high dose, 1000 to 2000 mg orally once a day, and had very high water solubility, so it make difficult to swallow tablet to requires high amount of sustained release agent. To overcome these challenges, we used novel metformin salts had relatively low water solubility to minimize sustaining excipient for small size of dosage form. six novel metformin salts were synthesized by making metformin free form under reaction with NaOH and adding acid salts. we confirmed metformin stearate had the lowest water solubility and showed half drug release in dissolution study at 12hour. In conclusion, novel metformin salts had low water solubility can be used to reduce the size of sustained metformin tablet for improving patient compliance.

• Restorative Dentistry and Endodontics
• /
• v.18 no.1
• /
• pp.27-37
• /
• 1993

The purpose of this study was to determine the fluroide release levels of new fluoride-containing liner/base cements and the fluoride uptake by dentin surfaces. Ten specimens of each brand (Fuji ionomer Type III, Fuji Lining LC, Timeline, Vitrebond and XR ionomer) were made, polymerized and placed in fluoride-free distilled water at $37^{\circ}C$, 100% relative humidity for 24 hours. The extracting solution of specimen was exchanged and fluoride release was measured daily for the 30 days. For fluoride uptake study, twenty-five extracted human lower molars were sectioned longitudinally in the mesiodistal direction with a diamond disc. Five teeth were filled with each material and then stored at $37^{\circ}C$, 100% humidity for 4 weeks. Fluoride uptake by dentin from the test materials was evaluated using electron probe micro X-ray analyzer. The following results were obtained : 1. The amounts of fluoride release showed no significant difference between Fuji ionomer Type III and Fuji Lining LC, but showed significant difference between other groups. XR ionomer released significantly greater fluoride than any other group(P<.001). 2. All the materials have a burst effect which more fluoride released in then first 3 day and showed significant decrease over the test period (P<0.001). 3. XR ionomer group showed fluoride penetration to approximately $50{\mu}m$ deep in dentin. But other material groups showed very little fluoride uptake by dentin.

• Journal of Environmental Science International
• /
• v.28 no.10
• /
• pp.851-861
• /
• 2019

In this study, we performed a sediment elution experiment to evaluate water quality in terms of phosphorus, as influenced by the dissolved oxygen consumed by sediments. Three separate model column treatments, namely, raw, calcined, and sonicated oyster shell powders, were used in this experiment. Essential phosphorus fractions were examined to verify their roles in nutrient release from sediment based on correlation analyses. When treated with calcined or sonicated oyster shell powder, the sediment-water interface became "less anaerobic," thereby producing conditions conducive to partial oxidation and activities of aerobic bacteria. Sediment Oxygen Demand (SOD) was found to be closely correlated with the growth of algae, which confirmed an intermittent input of organic biomass at the sediment surface. SOD was positively correlated with exchangeable and loosely adsorbed phosphorus and organic phosphorus, owing to the accumulation of unbound algal biomass-derived phosphates in sediment, whereas it was negatively correlated with ferric iron-bound phosphorus or calcium fluorapatite-bound phosphorus, which were present in the form of "insoluble" complexes, thereby facilitating the free migration of sulfate-reducing bacteria or limiting the release from complexes, depending on applied local conditions. PCR-denaturing gradient gel electrophoresis revealed that iron-reducing bacteria were the dominant species in control and non-calcined oyster shell columns, whereas certain sulfur-oxidizing bacteria were identified in the column treated with calcined oyster powder.

• Archives of Plastic Surgery
• /
• v.36 no.2
• /
• pp.147-152
• /
• 2009

Purpose: First web space contracture of the hand has been treated with various surgical techniques such as Z - plasty, local flap, pedicled flap, distant free flap, and anterolateral thigh free flap. Among those surgical techniques, anterolateral thigh free flap provide a thin and pliable flap, which is a useful method for correction of first web space contracture. Methods: From August 2003 to September 2007, authors selected 9 patients who had first web space contracture with limitation of thumb abduction within 30 degrees. All of patients had received first web contracture release with anterolateral thigh free flap. Age ranged from 24 to 51, and all the patients were male. Average follow up period was 12 months and authors performed photographic analysis of the thumb abduction angle of postoperative increase. Result: All the flaps were survived. Donor site was closed with primary closure in 8 cases and covered with split - thickness skin graft in 1 case. Average flap size was $8{\times}9cm$ and average thickness was 0.6 cm in suprafascial flap. The procedure resulted in increased thumb abduction angle of $34.7^{\circ}$ in average and showed concave shape of first web space in suprafascial flap. Additional operations were performed with Z - plasty in 3 cases, local flap in 5 cases, and opponensplasty in 3 cases. Conclusion: In suprafascial flap, we obtained relatively thin flap thickness and were able to make natural concave shape of first web space. In releasing severe contracture of the first web space, anterolateral thigh free flap provided a good coverage of appropriate thickness and pliable soft tissue and allowed limited donor site morbidity.

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.198-199
• /
• 2003

Chronic inflammatory processes are associated with pathology of Alzheimer's disease(AD). The expression of both cyclooxygenase-2(COX-2) and phospholipase A2(PLA2) appears to be strongly activated during AD, indicating the importance of inflammatory gene pathways as a response to brain injury. Stimulation of heterotrimeric G protein-coupled receptors including muscarinic receptors activates cytosolic PLA2 and receptor-mediated activation of PLA2 generates free fatty acids (i.e., arachidonic acid). (omitted)