• 폴리머
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• 제25권3호
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• pp.334-342
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• 2001

항생제의 서방형 전달을 위해 황산겐타마이신 gentamicin sulfate (GS)을 함유한 poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) 제형을 제조하였다. 본 연구에서는 제형의 두께, hydroxyvalerate (HV) 농도, 초기 약물함유량 및 첨가제의 함유에 따른 약물 방출거동의 변화를 조사하였다. 전자주사현미경을 이용하여 제형의 표면형태와 매트릭스 내부 약물의 조성을 관찰한 결과 약물방출 전과 후 모두 거칠고 다공성인 형태를 가짐을 알 수 있었다. 또한, HV와 첨가제의 함량이 증가할수록 약물이 고분자 매트릭스에 더 조밀하게 배열함을 관찰하였고, 이러한 구조가 약물의 방출에 영향을 미침을 알았다. HPLC를 이용하여 약물의 방출량을 측정한 결과, 모든 제형이 복합적인 방출 방향을 나타내었고, 일부 매트릭스는 30일 동안 거의 영차에 가까운 방출거동을 보였다. 이상의 결과에서 우리는 제형의 두께, 고분자 매트릭스의 조성, 첨가제의 함유량 등을 조절함으로 약물 방출을 제어할 수 있음을 확인하였다.

• Journal of Korean Neurosurgical Society
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• 제50권1호
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• pp.40-44
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• 2011

Objective : To evaluate the prevalence and risk factors of clopidogrel resistance, and association between thromboembolic complications and clopidogrel resistance in patient with stent-assisted angioplasty for atherosclerotic cerebrovascular disease. Methods : Between September 2006 and June 2008, clopidogrel resistance test was performed on 41 patients who underwent stent-assisted angioplasty for atherosclerotic cerebrovascular disease. It was performed before drug administration and about 12 hours after drug administration (loading dose : 300 mg, maintain dose : 75 mg). Two patients were excluded, and 41 patients were included (mean : $67.59{\pm}7.10$ years, age range : 41-79). Among 41 patients, 18 patients had intracranial lesions, and 23 had extracranial lesions. We evaluated the prevalence, risk factors and complications related to clopidogrel resistance. Results : Twenty-one patients (51.2%) showed clopidogrel resistance [intracranial : 10 patients (55.6%), extracranial : 11 patients (47.8%)] and no clopidogrel resistance was seen in 20 patients. Hypercholesterolemia was an indepedent risk factor of clopidogrel resistance. Stent-assisted angioplasty was technically successful in all patients, but acute in-stent thrombosis occurred in 5 patients with intracranial lesions (4 patients with clopidogrel resistance and 1 without clopidogrel resistance). Acute thrombi were completely lysed after intra-arterial infusion of abciximab. Conclusion : There was relatively high prevalence of clopidogrel resistance in patients with atherosclerotic cerebrovascular disease. Hypercholesterolemia was an independent predictive factor of clopidogrel resistance. Acute in-stent thrombosis was more frequently seen in the clopidogrel resistant group. Therefore, clopidogrel resistance test should be performed to avoid thromboembolic complications related to stent-assisted angioplasty for atherosclerotic cerebrovascular disease, especially patients with hypercholeterolemia and intracranial lesion.

• Macromolecular Research
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• 제14권1호
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• pp.66-72
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• 2006

The purpose of this study is to develop novel nanoparticles based on polyion complex formation between low molecular weight water-soluble chitosan (LMWSC) and all-trans retinoic acid (atRA). LMWSC nanoparticles encapsulating atRA based on polyion complex were prepared by mixing of atRA into LMWSC aqueous solution using ultrasonication. In FTIR spectra, the carbonyl group of atRA at 1690 $cm^{-1}$ disappeared or decreased when ion complexes were formed between LMWSC and atRA. In ${1}^H$ NMR spectra, specific peaks of atRA disappeared when atRA-encapsulated LMWSC (RAC) nanoparticles were reconstituted into $D_{2}O$ while specific peaks both of atRA and LMWSC appeared in $D_{2}O$/DMSO (1/3, v/v) mixture. XRD patterns also showed that the crystal peaks of atRA were disappeared by encapsulation into LMWSC nanoparticles. LMWSC nanoparticles encapsulating atRA have spherical shapes with particle size below 200 nm. The mechanism of encapsulation of atRA into LMWSC nanoparticles was thought to be an ion complex formation between LMWSC and atRA. LMWSC nanoparticles showed high atRA loading efficiency over 90$\%$ (w/w). AtRA was continuously released from nanoparticles over 10 days. In in vitro cell cytotoxicity test, free atRA showed higher cytotoxic effect against CT 26 colon carcinoma cell line on 1 day. However, RAC nanoparticles showed similar cytotoxicity against CT 26 cells on 2 day. These results suggest the potential for the introduction of LMWSC nanoparticles into various biomedical fields such as drug delivery.

• Macromolecular Research
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• 제16권1호
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• pp.57-61
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• 2008

Chitosan is normally acylated and subsequently conjugated with drugs for biomedical applications. This study examined the relationship between the succinylation and gelation behaviors of glycol chitosan. Glycol chitosan was acylated with succinic anhydride under a wide variety of reaction conditions, such as different molar ratios of succinic anhydride to glucosamine, different methanol content in the reaction media, and different reaction temperatures. Among these reaction parameters, the methanol content in the solvent played an important role in determining the regioseletive succinylating site. N-succinylation and N-N cross-linking occurred regardless of the reaction conditions. However, O-succinylation was observed under specific conditions, i.e. a methanol content> 0.6 (v/v) and a reaction temperature> $25^{\circ}C$. O-succinylation accelerated the N-O cross-linking of glycol chitosan, and led to gelation. The N-succinylated glycol chitosans were water-soluble, whereas the N-and O-succinylated glycol chitosans fonned a gel. These physico-chemical structural differences in the succinylated glycol chitosans would definitely influence subsequent drug-conjugation reactions and consequently the drug loading and release kinetics.

• Journal of Pharmaceutical Investigation
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• 제37권1호
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• pp.15-22
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• 2007

An oil-in-water solvent evaporation method was used to prepare the cyclosporin A (CyA)-loaded nanoparticles varying in poly (D,L-lactide-co-glycolide) (PLGA) polymer (RG 502H, RG 503H) and the amount of additive ethyl myristate (EM) or chitosan (CS). The particles were characterized for drug loading and entrapment efficiency by HPLC, surface morphology by scanning electron microscopy, particle size by dynamic light scattering and surface charge by Zetapotential. The results showed drug loadings ranging from 10.9% to 15.8% with high encapsulation efficiency (82.0-97.8%). SEM and DLS studies showed discrete and spherical particles with smooth surfaces and mean size ranging 257.6-721.7 nm. The additive EM or CS did not change the mean sizes of the nanoparticles, whereas by the coating effect of CS, the Zetapotential values of the CS-added nanoparticles were moved to the more positive direction as the amount of CS was increased. From the pharmacokinetic analysis, the nanoparticles formulations showed the higher bioavailability and MRT than $Neoral^{\circledR}$ While little adding effect of EM or CS was detected in pharmacokinetic profile when RG 503H was used as polymer carrier, more noticeable different pharmacokinetic behaviors could be observed in case of RC 502H. EM incorporation was found to elevate the $K_{el}$, whereas CS coating resulted in the decrease of F and $K_{el}$, which seems to be due to the function of CS as a barrier and a mucoadhesive coating.

• 멤브레인
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• 제27권6호
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• pp.511-518
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• 2017

막유화(membrane emulsification, ME)는 SPG 막과 같이 균일한 크기의 세공을 갖는 막을 사용하여 좁은 입도분포의 에멀젼을 제조하는 기술이다. 본 연구에서는 막유화법으로 형성시킨 다중 에멀젼을 사용하여 폴리카프로락톤(PCL) 마이크로캡슐의 제조를 연구하였다. 먼저 초음파 유화기로 $W_1/O$ 단일 에멀젼을 제조한 후, premix 막유화를 적용하여 $W_1/O/W_2$ 다중 에멀젼을 형성시킨 후 용매 증발을 통해 모델 약물인 BSA가 담지된 PCL 마이크로캡슐을 제조하였다. 연속상에 대한 분산상의 비율(D/C ratio), PCL 농도, 유화제 농도, 모델 약물의 농도, 막간 압력차 등 막유화 변수가 제조된 마이크로캡슐의 입경과 입도 분포에 미치는 영향을 실험하였다. Premix-ME를 적용하여 평균 입경 $5{\sim}6{\mu}m$의 균일한 크기를 갖는 모델 약물 BSA의 함침량이 약 26%인 다중 코어형 PCL 마이크로캡슐을 제조할 수 있었다.

• Journal of Veterinary Science
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• 제23권3호
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• pp.48.1-48.12
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• 2022

Background: The poor intracellular concentration of enrofloxacin might lead to treatment failure of cow mastitis caused by Staphylococcus aureus small colony variants (SASCVs). Objectives: In this study, enrofloxacin composite nanogels were developed to increase the intracellular therapeutic drug concentrations and enhance the efficacy of enrofloxacin against cow mastitis caused by intracellular SASCVs. Methods: Enrofloxacin composite nanogels were formulated by an electrostatic interaction between gelatin (positive charge) and sodium alginate (SA; negative charge) with the help of CaCl₂ (ionic crosslinkers) and optimized by a single factor test using the particle diameter, zeta potential (ZP), polydispersity index (PDI), loading capacity (LC), and encapsulation efficiency (EE) as indexes. The formation mechanism, structural characteristics, bioadhesion ability, cellular uptake, and the antibacterial activity of the enrofloxacin composite nanogels against intracellular SASCVs strain were studied systematically. Results: The optimized formulation was comprised of 10 mg/mL (gelatin), 5 mg/mL (SA), and 0.25 mg/mL (CaCl₂). The size, LC, EE, PDI, and ZP of the optimized enrofloxacin composite nanogels were 323.2 ± 4.3 nm, 15.4% ± 0.2%, 69.6% ± 1.3%, 0.11 ± 0.02, and -34.4 ± 0.8 mV, respectively. Transmission electron microscopy showed that the enrofloxacin composite nanogels were spherical with a smooth surface and good particle size distributions. In addition, the enrofloxacin composite nanogels could enhance the bioadhesion capacity of enrofloxacin for the SASCVs strain by adhesive studies. The minimum inhibitory concentration, minimum bactericidal concentration, minimum biofilm inhibitory concentration, and minimum biofilm eradication concentration were 2, 4, 4, and 8 ㎍/mL, respectively. The killing rate curve had a concentration-dependent bactericidal effect as increasing drug concentrations induced swifter and more radical killing effects. Conclusions: This study provides a good tendency for developing enrofloxacin composite nanogels for treating cow mastitis caused by intracellular SASCVs and other intracellular bacterial infections.

• Preventive Nutrition and Food Science
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• 제18권3호
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• pp.169-174
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• 2013

The acute and subacute hypoglycemic and antihyperglycemic effects of drinkable ripe onion juice (Commercial product name is "Black Onion Extract") were investigated in normal and streptozotocin-induced diabetic rats. For tests of acute and subacute hypoglycemic effects, ripe onion juice (5 and 15 mL/kg b.w.) was administered by oral gavage to normal Sprague Dawley rats and measurements of fasting glucose levels and oral glucose tolerance tests were performed. Tolbutamide was used as a reference drug at a single oral dose of 250 mg/kg b.w. To test anti-hyperglycemic activity, the ripe onion juice was administered to streptozotocin-induced diabetic rats by oral gavage at single dose of 15 mL/kg b.w. per day for 7 consecutive days. Oral administration of the ripe onion juice at either dosed level of 5 or 15 mL/kg b.w. showed no remarkable acute hypoglycemic effect in normal rats. The two dosed levels caused a relatively small reduction, only 18% and 12% (5 and 15 mL/kg b.w., respectively) decrease in glucose levels at 2 h after glucose loading in normal rats. However, at 3 h after glucose loading, blood glucose levels in the ripe onion juice-dosed rats were decreased to the corresponding blood glucose level in tolbutamide-dosed rats. Although showing weak hypoglycemic potential compared to that of tolbutamide, oral administration of ripe onion juice (15 mL/kg b.w.) for a short period (8 days) resulted in a slight reduction in the blood glucose levels that had elevated in Streptozotocin-induced diabetic rats. In conclusion, these results suggest that the commercial product "Black Onion Extract" may possess antihyperglycemic potential in diabetes.

• The Korean Journal of Pain
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• 제6권1호
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• pp.49-54
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• 1993

The use of intravenous patient-controlled analgesia is an effective and increasingly used means of providing postoperative pain relief. Recently a non-electric, disposable and portable infusor, the Baxter $Infusor^{(R)}$, has developed. This delivers not only a continuous drug infusion but can also deliver extradoses of medication on demand. The present study examined the benefits of two kinds of analgesics for pain management in 28 patients undergoing gynecological surgery. One group, 14 patients, received i.v. meperidine 0.5 mg/kg as loading dose in the recovery room and PCA with meperidine 3 mg/kg/day for 3 days only(M group). In the other group, 14 patients, also received i.v. meperidine 0.5 mg/kg as loading dose in the recovery room and PCA meperidine 3 mg/kg/day for 3 days and droperidol 5 mg(MD group). The PCA device used was the Baxter $Infusor^{(R)}$. This unit was fitted with patient control module which had a flow rate 0.5 ml/hr and the lockout time was 15 min. Resulting from the study, the MD patients in the first and second days post-operatively, reported less pain compared with the M group. VAPS(Visual Analogue Pain Scales) values were $3.52{\pm}l.61$ vs. $2.22{\pm}0.69$, $2.38{\pm}1.12$ vs. $1.45{\pm}0.48$ and $1.93{\pm}1.65$ vs. $0.98{\pm}0.36$, respectively pertaining to M and MD groups. In conclusion, the MD group with meperidine and droperidol(mixed regimen) provided more effective postoperative analgesia than M group(meperidine only).

• Journal of Korean Neurosurgical Society
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• 제55권4호
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• pp.185-189
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• 2014

Objective : General anesthesia is often preferred for endovascular coiling of intracranial aneurysm at most centers. But in the authors' hospital, it is performed under monitored anesthesia care (MAC) using dexmedetomidine. To determine the feasibility and safety of this approach, the authors reviewed our initial experience. Methods : Retrospective data was analyzed from July 2012 to November 2012. We performed coil embolization in 28 cases using this method. Among them, for statistical significance, we analyzed 12 cases in which the procedure time exceeded an hour. Vital signs were analyzed every 10 minutes. Depth of sedation was measured according to the Ramsay sedation scale and frequency of the repeated roadmap image(s) caused by movement of the patient's head during the procedure. Results : All procedures were completed without occurrence of procedure related complications. Under MAC using dexmedetomidine, vital signs of the patients were stable, no statistical significance regarding hemodynamic and respiratory parameters was observed between time points (p>0.05). Adequate sedation was achieved. Mean Ramsay sedation scale was $3.67{\pm}1.61$ (2 to 6). Repeated roadmap image(s) due to patient's factor occurred in only one case. The mean dosage of drug for adequate sedation for the procedure was $0.65{\pm}0.12mcg/kg/hr$ without loading doses. Conclusion : To the best of my knowledge, this is the first report published in English using the method of monitored anesthesia with dexmedetomidine for intracranial aneurysm coiling. Monitored anesthesia care using dexmedetomidine without loading dose for embolization of intracranial aneurysms appeared to be a safe and effective alternative to general anesthesia.