Biomedical subjects

Jong Soo Woo

Publications and source records attributed to Jong Soo Woo.

12 recordsLinked to original sources

PubMed2006

Analysis of carbamazepine and its active metabolite, carbamazepine-10,11-epoxide, in human plasma using high-performance liquid chromatography.

A sensitive method based on high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection was developed for the determination of carbamazepine (CBZ) and one of its active metabolites, carbamazepine-10,11-epoxide (CBZ-E) in human plasma. CBZ, CBZ-E and the internal standard (IS) 10,11-dihydrocarbamazepine were extracted from human plasma into methyl tert-butyl ether. CBZ, CBZ-E and the IS were successfully separated on an RP C18 column with a mobile phase of acetonitrile:methanol:water (18:19:63, v/v/v) and monitored via UV detection at 210 nm. The calibration curves were linear over the concentration ranges of 0.01-10 microg/mL for CBZ and 0.005-5 microg/mL for CBZ-E in human plasma, respectively. The method displayed excellent sensitivity, precision and accuracy, and was successfully applied to the quantification of CBZ and CBZ-E in human plasma after oral administration of a single 200 mg CBZ CR tablet. This method is suitable for bioequivalence studies following single doses given to healthy volunteers.

Carbamazepine↗

PubMed2006

Quantitative determination of voglibose in pharmaceutical tablets using high-performance liquid chromatography-fluorescence detection with post-column derivatization and mass spectrometric detection.

A highly sensitive liquid chromatographic procedure with post-column derivatization using fluorescence detection (LC-FD) was developed and validated for the determination of voglibose in pharmaceutical tablets. Sample pre-treatment included a simple extraction and centrifugation without pre-column derivatization. Taurine and sodium periodate dissolved in water was used as a post-column reagent. Detection was performed at an excitation wavelength of 350 nm and an emission wavelength of 430 nm. LC separation was carried out in less than 25 min. In addition to the LC procedure with post-column derivatization, an LC-MS assay procedure was also investigated for the analysis of voglibose without derivatization. Voglibose was detected in an electrospray ionization (ESI) mode with single ion recording (SIR, m/z 268.1). After selection of the optimum conditions, both assay methods were validated, providing good performances with respect to precision, linearity and accuracy. Linearities of both methods were obtained with an average r(2)>0.999. The lower limits of detection (LLOD) were 9.4 and 18 ng/ml for LC-FD and LC-MS, respectively. Both methods could be successfully applied to the quantification of voglibose in commercially available tablets.

Chromatography, High Pressure Liquid↗

PubMed2006

Sensitive column-switching high-performance liquid chromatography method for determination of propiverine in human plasma.

A sensitive column-switching high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection was developed for the determination of propiverine in human plasma. Propiverine and internal standard, oxybutynin, were extracted from human plasma that had been made basic with 5N sodium hydroxide into methyl tert-butyl ether. The extracted plasma sample was injected onto the HPLC system consisting of a pretreatment column, a concentrating column, and an analytical column, which were connected with a six-port switching valve. The assay was linear in concentration ranges of 2-200 ng/ml for propiverine in human plasma. This method showed excellent sensitivity (a limit of detection of 0.5 ng/ml), good precision and accuracy. This method is suitable for bioequivalence studies following single dose in healthy volunteers.

Benzilates↗

PubMed2005

Trials of clear aceclofenac-loaded soft capsules with accelerated oral absorption in human subjects.

To develop an effective oral drug delivery system with accelerated absorption in human subjects for a poorly water-soluble acelofenac, five aceclofenac-loaded soft capsule preparations containing various ratios of different solubilizers were prepared and their dissolution tests were carried out. Among five preparations tested, a preparation with ethanolamine was selected as a formula of aceclofenac soft capsule (Korea United Pharm. Co. Ltd., Clanza S, since it was clear in appearance and showed the fastest dissolution rate due to the solubility-enhancing effect of aceclofenac. To evaluate and compare the pharmacokinetics of acelofenac-loaded soft capsules with the conventional aceclofenac tablets (Dae-Woong Pharm. Co. Ltd., Airtal) in human subjects; 14 normal healthy male volunteers (age 20-25 years old) were divided into two groups and a randomized 2 x 2 cross-over study was performed. Following oral administration of one tablet or capsule, each containing 100mg of aceclofenac, blood samples were collected at the predetermined time intervals and the concentration of aceclofenac in plasma was determined by HPLC method using UV detector. The AUC, Cmax, MRT, t1/2 and Kel of aceclofenac delivered from soft capsule were not significantly different from those from aceclofenac-loaded conventional tablet. However, soft capsule gave significantly higher initial concentration and significantly faster Tmax of aceclofenac than did conventional tablet, suggesting that the soft capsule with ethanolamine showed the faster absorption of aceclofenac in human subjects. Thus, the clear aceclofenac-loaded soft capsule with ethanolamine was a more effective oral dosage form with fast absorption for poorly water-soluble aceclofenac.

Absorption↗

PubMed2005

Left subclavian artery free graft as a salvage technique after failed coronary artery transfer in arterial switch operation.

Coronary artery transfer in transposition of the great arteries with single coronary artery or intramural coronary artery is still a technically demanding procedure. We present a technique of left coronary bypass using a free graft of left subclavian artery for the management of failed coronary artery transfer of left intramural coronary artery.

Coronary Angiography↗

PubMed2005

Preparation and characterization of solid dispersions of itraconazole by using aerosol solvent extraction system for improvement in drug solubility and bioavailability.

The objective of this study was to elucidate the feasibility to improve the solubility and bioavailability of poorly water-soluble itraconazole via solid dispersions by using supercritical fluid (SCF). Solid dispersions of itraconazole with hydrophilic polymer, HPMC 2910, were prepared by the aerosol solvent extraction system (ASES) under different process conditions of temperature/pressure. The particle size of solid dispersions ranged from 100 to 500 nm. The equilibrium solubility increased with decrease (15 to 10 MPa) in pressure and increase (40 to 60 degrees C) in temperature. The solid dispersions prepared at 45 degrees C/15 MPa showed a slight increase in equilibrium solubility (approximately 27-fold increase) when compared to pure itraconazole, while those prepared at 60 degrees C/10 MPa showed approximately 610-fold increase and no endothermic peaks corresponding to pure itraconazole were observed, indicating that itraconazole might be molecularly dispersed in HPMC 2910 in the amorphous form. The amorphous state of itraconazole was confirmed by DSC/XRD data. The pharmacokinetic parameters of the ASES-processed solid dispersions, such as Tmax, Cmax, and AUC(o-24 h) were almost similar to Sporanox capsule which shows high bioavailability. Hence, it was concluded that the ASES process could be a promising technique to reduce particle size and/or prepare amorphous solid dispersion of drugs in order to improve the solubility and bioavailability of poorly water-soluble drugs.

Administration, Oral↗

PubMed2005

Arterial switch operation for transposition of the great arteries with coronary arteries from a single aortic sinus.

BACKGROUND: The reimplantation of the coronary arteries from a single aortic sinus (single sinus coronary artery) in an arterial switch operation remains a technically challenging procedure. The technique of coronary transfer in this situation should be individualized depending on coronary ostial anatomy. We reviewed our techniques of coronary reimplantation with early and midterm results. METHODS: Among 103 patients who underwent arterial switch operations from March 1994 to June 2004, 16 (15.5%) had single sinus coronary artery (median age, 9 days; mean body weight, 3.5 kg). Fourteen patients (14/16, 87.5%) had coronary arteries from right facing sinus (sinus 2). Of these 14 patients, 11 had separate ostia including intramural course of the left coronary artery (n = 9) and 3 had single ostium. Two patients (2/16, 12.5%) had coronary arteries from left facing sinus (sinus 1) with single ostium. Aortic arch obstruction was associated in 5 patients. RESULTS: All 5 single sinus coronary arteries with single ostium were reimplanted with the trap-door technique. Of the 11 patients with separate ostia, 8 underwent coronary transfer with the aortocoronary flap technique and 3 with the double-button technique. Two of the 3 patients who underwent the double-button technique required left coronary artery bypass using left subclavian artery free graft as the salvaging procedure. There was one early death (1/16, 6.3%), which occurred during our earlier experience, in a patient who had arch anomaly and intramural left coronary artery. There was no late death. All but one patient had good ventricular function. CONCLUSIONS: All single sinus coronary artery with single ostium can be transferred with the trap-door technique with excellent results. The aortocoronary flap technique in those with separate ostia with or without intramural left coronary artery may be a good option. However, reimplantation of the intramural left coronary artery using separate coronary buttons should be performed with great care.

Anastomosis, Surgical↗

PubMed2005

Coronary reimplantation after neoaortic reconstruction can yield better result in arterial switch operation: comparison with open trap door technique.

BACKGROUND: Accurate coronary reimplantation is the most important component in the arterial switch operation. It is especially demanding for the less experienced surgeons. We compared the result of the technique of coronary reimplantation after neoaortic reconstruction with that of the open trap door technique. METHODS: From March 1994 to June 2004, 103 consecutive patients underwent the arterial switch operation by one surgeon. Patients who underwent coronary artery transfer with other modified techniques were excluded. Diagnoses of 94 patients were transposition of the great arteries with intact ventricular septum (n = 50), transposition of the great arteries with ventricular septal defect (n = 26), and the Taussig-Bing anomaly (n = 18). An aortic arch anomaly was present in 13 patients. The median age of the patients was 12 days and the mean body weight was 3.5 kg. Coronary reimplantation after neoaortic reconstruction was applied to 34 patients (group I), and the open trap door technique was applied to the rest (group II). RESULTS: Preoperative data were similar in both groups. Four patients in group II required intraoperative revision of a transferred coronary artery, and 1 patient with an intramural left coronary artery in group I had a conversion to free grafting using the left subclavian artery. Overall early mortality was 17.0% (16 of 94). Mortality in group I (1 of 34; 2.9%) was significantly lower than in group II (15 of 60; 25.0%) (p = 0.008). The leading cause of death in group II was low cardiac output (n = 9). During the follow-up, an aortic regurgitation of greater than mild was detected in 2 patients in group II. CONCLUSIONS: Coronary reimplantation after neoaoartic reconstruction is an attractive method to minimize coronary artery transfer-related mortality or morbidity.

Cardiac Surgical Procedures↗

PubMed2005

Cefuroxime axetil solid dispersions prepared using solution enhanced dispersion by supercritical fluids.

Cefuroxime axetil (CA) solid dispersions with HPMC 2910/PVP K-30 were prepared using solution enhanced dispersion by supercritical fluids (SEDS) in an effort to increase the dissolution rate of poorly water-soluble drugs. Their physicochemical properties in solid state were characterized by differential scanning calorimeter (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared spectrometry (FT-IR) and scanning electron microscopy. No endothermic and characteristic diffraction peaks corresponding to CA were observed for the solid dispersions in DSC and PXRD. FTIR analysis demonstrated the presence of intermolecular hydrogen bonds between CA and HPMC 2910/PVP K-30 in solid dispersions, resulting in the formation of amorphous or non-crystalline CA. Dissolution studies indicated that the dissolution rates were remarkably increased in solid dispersions compared with those in the physical mixture and drug alone. In conclusion, an amorphous or non-crystalline CA solid dispersion prepared using SEDS could be very useful for the formulation of solid dosage forms.

Anti-Bacterial Agents↗

PubMed2003

Pulmonic valve annular enlargement with valve repair in tetralogy of Fallot.

We present an operative technique of pulmonic valve annular enlargement with concomitant valve repair using two pericardial patches to reduce pulmonary regurgitation after complete repair of tetralogy of Fallot. We have used this technique in 18 patients with tetralogy of Fallot with excellent results.

Cardiac Surgical Procedures↗

PubMed2003

Enhanced oral bioavailability of paclitaxel by coadministration of the P-glycoprotein inhibitor KR30031.

PURPOSE: In an attempt to improve the oral bioavailability of paclitaxel, a novel P-glycoprotein inhibitor, KR30031, which is verapamil analog with fewer cardiovascular effects, was coadministered with paclitaxel, and to elucidate other possible causes of the low oral bioavailability of paclitaxel, an inhibitor of hepatic metabolism, ketoconazole, was also coadministered with paclitaxel. METHODS: In vivo oral absorption was tested in rats, and an in vitro study was also performed with a Caco-2 cell monolayer to identify the extent of P-glycoprotein inhibition. RESULTS: After coadministration of paclitaxel with ketoconazole, KR-30031, or KR-30031 and ketoconazole, bioavailability was increased about 1.6-, 7.5-, or 8.9-fold as compared with control, respectively. These results show that P-glycoprotein plays a major role in the oral bioavailability of paclitaxel. The effect of ketoconazole on oral bioavailability of paclitaxel was limited relative to the P-glycoprotein inhibition effect of KR-30031. In vitro study of Caco-2 cell transport showed that paclitaxel permeation was significantly higher when the drug was given from the basolateral side as compared to the permeation from the apical side, indicating the involvement of an enzyme reaction in the active efflux mechanism. Apical-to-basolateral transport of paclitaxel was increased in the presence of KR-30031. The ability of KR-30031 to reduce this efflux transport is equal to that of verapamil, a well-known P-glycoprotein inhibitor. CONCLUSIONS: Our findings suggest that about 54% of a paclitaxel oral dose is extruded to the gut lumen by P-glycoprotein. Thus, the bioavailability of paclitaxel could be enhanced by coadministration of a P-glycoprotein inhibitor, KR-30031.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2002

Rapid and sensitive determination of sertraline in human plasma using gas chromatography-mass spectrometry.

A method for the determination of sertraline in human plasma using gas chromatography-mass spectrometry (GC-MS), with the selected ion-monitoring (SIM) mode, was described. The following was used in this study: (1) single liquid-liquid extraction at alkaline pH after deproteinization of plasma protein and (2) perfluoroacylation with HFBA, which has higher sensitivity (about 10-fold) compared with previous reported derivatization. The detection limit for the SIM of sertraline as an N-HFB derivative was 0.1 ng/ml, and its recovery was 80-85%. The linear response was obtained in the range of 0.2-10.0 ng/ml with a correlation coefficient of 0.999. The coefficient of variation (C.V.%) was less than 12.1% in the 1-30 ng/ml, and less than 18.2% at 0.2 ng/ml, and the accuracy was less than 10% at all of the concentration range. These findings indicate that this assay method has adequate precision and accuracy to determine the amount of sertraline in human plasma. After pharmacokinetics was performed with this assay method following oral administration of sertraline hydrochloride in man, moment analysis revealed that pharmacokinetic parameters for sertraline (Cmax, 10.3 ng/ml; Tmax, 8.0 h; T(1/2) 28.6 h) were similar to previously reported results. These results indicate that this simple and sensitive assay method is readily applicable to the pharmacokinetic studies of sertraline.

Adult↗