• Korean Journal of Veterinary Research
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• v.32 no.1
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• pp.35-39
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• 1992

SMZ is one of the most widely used antibacterial agents in veterinary medicine. It is also used as a growth promotant in many species of domestic animals There are marked species differences in its metabolism and pharmacokinetics. However, its pharmacokinetic and metabolism in rabbits. which are ragarded not only as good laboratorty animals hut also as good economical animals in its own, are lacking. Sex-differences in drug metabolism are well recognized in wide range of animal species including rats. Males are known to he more active than females. It is also know that there are Significant differences in the direction of metabolic pathways. But recently, female goats are reported to be more active in the metabolie capacity of SMZ than the other sex by Dutch researchers at Utrecht. Therefore, it is not easy to make general conclusicn of having higher SMZ metal-die capacity in the male compared to the opposite sex in every animal species. In this regard, the study on metabolic pattern of SMZ in rabbits, which are regarded as hervivorous, is of interest because the dietary habbits of rabbit are comparable to thai of goal, NEW Zealand White rabbits of each sex were given SMZ(35mg/kg) as a bolus injection into the marginalean, vein in order to study its pharmacokinetic profiles(using plasma) anc metabolic pattem(24h urine) as specified in the methods anc materials. 1. In the rabbit, the major metabolic pathway of SMZ was the acetylation(the formation of $N_4AcSMZ$). There were hydroxylation pathways(50HSMZ, $6CH_2OHSMZ$) as well, in the metabolism of SMZ in the rabbit, but minor pathways. 2. No sex differences in the metabolic direction of SMZ and its metabolites formation were found from the urinary excreted metabolites of SMZ out of 24h collected urine. 3. The concentration-time curves of SMZ(35mg/kg, iv) in the plasma compartment were fitted to a one-compartment open model when using a computer program(NONLIN). There was also no difference in the pharmacokinetic pattem of SMZ between two sexes. 4. The emergence of $N_4AcSMZ$ metabolized from SMZ was very fast in the plasma of the rabbit The elimination of $N_4AcSMZ$ was prolonged as compared to that of the parent drug Vie found no sex difference in the elimination pattern of $N_4AcSMZ$ in the rabbit.

• Journal of Pharmaceutical Investigation
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• v.35 no.3
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• pp.179-185
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• 2005

Acebrophylline is a compound produced by salifying ambroxol with theophylline-7 -acetic acid. After acebrophylline administration, the salt splits into these two components which feature a peculiar pharmacokinetic behavior, an adequate ambroxol and a low theophylline-7-acetic acid serum levels. The purpose of the present study was to evaluate the bioequivalence of two acebrophylline capsules, Surfolase (Hyundai Pharm. lnd. Co., Ltd.) and Burophil (Kuhnil Pharm. Co., Ltd.), according to the guidelines of the Korea Food and Drug Administration (KFDA). The release of ambroxol from the two acebrophylline formulations in vitro was tested using KP VIII Apparatus II method with various dissolution media (pH 1.2, 4.0, 6.8 buffer solution and water). Twenty eight healthy male subjects, $23.25{\pm}1.43$ years in age and $64.82{\pm}6.77$ kg in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After two capsules containing 100 mg as acebrophylline were orally administered, blood was taken at predetermined time intervals and the concentrations of ambroxol in serum were determined using HPLC with electrochemical detector (ECD). The dissolution profiles of two formulations were similar at all dissolution media. In addition, the pharmacokinetic parameters such as $AUC_t$, $C_{max}$ and $T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug Surfolase, were -1.64, -3.33 and -0.92% for $AUC_t$, $C_{max}$ and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25 $(e.g., \;log\;0.93{\sim}log\;1.05\;and\;log\;0.88{\sim}log\;1.05$ for $AUC_t$, and $C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Burophil capsule was bioequivalent to Surfolase capsule.

• Journal of Life Science
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• v.29 no.6
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• pp.653-661
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• 2019

The first small interfering RNA (siRNA) therapeutics have recently been approved by the Food and Drug Administration in the U.S., and the demand for a new RNA therapeutics bioanalysis method-which is essential for pharmacokinetics, including the absorption, distribution, metabolism, and excretion of siRNA therapeutics-is rapidly increasing. The stem-loop real-time qPCR (RT-qPCR) assay is a useful molecular technique for the identification and quantification of small RNA (e.g., micro RNA and siRNA) and can be applied for the bioanalysis of siRNA therapeutics. When the anti-HPV E6/E7 siRNA therapeutic was used in preclinical trials, the established stem-loop RT-qPCR assay was validated. The limit of detection was sensitive up to 10 fM and the lower limit of quantification up to 100 fM. In fact, the reliability of the established test method was further validated in three intra assays. Here, the correlation coefficient of $R^2$>0.99, the slope of -3.10 ~ -3.40, and the recovery rate within ${\pm}20%$ of the siRNA standard curve confirm its excellent robustness. Finally, the circulation profiles of siRNAs were demonstrated in rat serum, and the pharmacokinetic properties of the anti-HPV E6/E7 siRNA therapeutic were characterized using a stem-loop RT-qPCR assay. Therefore, the stemloop RT-qPCR assay enables accurate, precise, and sensitive siRNA duplex quantification and is suitable for the quantification of small RNA therapeutics using small volumes of biological samples.

• Korean Journal of Clinical Pharmacy
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• v.11 no.2
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• pp.49-56
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• 2001

Acetyl-L-carnitine (ALC), an endogenous component of the L-carnitine family, is a naturally existing molecule synthesized from L-carnitine (LC) by carnitine acetyl transferase. ALC has been shown to improve the cognitive performance of patients suffering from dementia of the Alzheimer's type and proposed for treating Alzheimer's disease in pharmacological doses. The purpose of the present study was to evaluate the bioefuivalence of two ALC tablets, $Nicetile^{TM} (Dong-A Pharmaceutical Co.) and $L-Cartin^{TM}$ (Kuhn Il Pharmaceutical Co.), according to the guidelines of Korea Food and Drug Administration (KFDA). The ALC release from the two ALC tablets in vitro was tested using KP VII Apparatus II method in various dissolution media (pH 1.2, 6.0 and 6.8). Twenty six normal male volunteers, $24.46\pm3.67$ years in age and $64.45\pm5.54$ kg in body weight, were divided into two groups and a randomized $2\times2$cross-over study was employed. After one tablet containing 500 mg of ALC was orally administered, blood was taken at predetermined time intervals and the concentrations of ALC in serum were determined using HPLC with fluorescence detector. Because of the presence of endogenous ALC, the calibration was performed using dialyzed serum. The dissolution profiles of the two ALC tablets were similar in all the dissolution media. The pharmacokinetic parameters such as $AUC_t,\;C_{max}\;and\;T_{max}$ were calculated and ANOVA was utilized for the statistical analysis of the parameters. The results showed that the differences in $AUC_t,\;C_{max}\;and\;T_{max}$ between two tablets were $0.35\%,\;0.93\%\;and\;2.34\%$ respectively, when calculated against the $Nicetile^{TM} tablet. The powers $(1-\beta)\;for\;AUC_t$ , and Cmax were $98.72\%\;and\;85.48\%$, respectively. Minimum detectable differences $(\Delta)\;at\;\alpha=0.05\;and\;1-\beta=0.8$ were less than $20\%,\;(e.g.,\;13.21\%\;and\;18.42\%\;for\;AUC_t,\;and\;C_{max}$ respectively). The $90\%$ confidence intervals were within $\pm20\%\;(e.g.,\;-7.38\sim8.09\;and\;-9.86\sim11.72\;for\;AUC_t,\;and\;C_{max}$, respectively). These two parameters met the criteria of KFDA for bioequivalence, indicating that $L-Cartin^{TM}$ tablet is bioequivalent to $Nicetile^{TM} tablet.

• Journal of Society of Preventive Korean Medicine
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• v.18 no.2
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• pp.89-100
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• 2014

Objective : The co-administration effects of Gongjindan (GJD) on the pharmacokinetics (PK) of sorafenib were observed as a process of the comprehensive and integrative medicine. Methods : After sorafenib treatment, GJD was administered within 5 min. The plasma were collected at 30min before administration, 30min, 1, 2, 3, 4, 6, 8 and 24hrs after end of GJD treatment, and plasma concentrations of sorafenib were analyzed using LC-MS/MS methods. PK parameters of sorafenib ($T_{max}$, $C_{max}$, AUC, $t_{1/2}$ and $MRT_{inf}$) were analysis as compared with sorafenib single administered rats. Results : The absorption of sorafenib were significantly increased at 30min, 1, 6 and 6hrs after co-administration with GJD as compared with sorafenib single treated rats. Accordingly, the $AUC_{0-t}$ (47.20%) of sorafenib was significantly increased but $t_{1/2}$ (-30.63%) and $MRT_{inf}$ (-34.11%) in co-administered rats were non-significantly decreased. These findings are considered as direct evidences that GJD increased the oral bioavailability of sorafenib through increase of the absorption, when they co-administered within 5min. Conclusion : Based on the results, co-administration of GJD increased the oral bioavailability of sorafenib through increase of the gastrointestinal absorption. It is considered that the more detail pharmacokinetic studies should be tested to conclude the effects of GJD on the pharmacokinetics of sorafenib, when they were co-administered, like the effects after co-administration with reasonable intervals considering the $T_{max}$ of sorafenib (about 3.5hr-intervals) and after repeated co-administrations.Hence, concomitant uses of GJD with sorafenib may require close monitoring for potential drug interactions.

• Journal of Pharmaceutical Investigation
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• v.33 no.3
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• pp.237-243
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• 2003

Erdosteine, the thiol derivatives chemically related to cysteine, is a mucolytic and mucoregulator agent which modulates mucus production and viscosity and increases mucociliary transport. The purpose of the present study was to evaluate the bioequivalence of two erdosteine capsules, Erdos (Dae Woong Pharmaceutical Co., Korea) and Erblon (Kuhn Il Pharmaceutical Co., Korea), according to the guidelines of Korea Food and Drug Administration (KFDA). The erdosteine release from the two erdosteine capsules in vitro was tested using KP VII Apparatus II method with various different kinds of dissolution media (pH 1.2, 4.0, 6.8 buffer solution and water). Twenty four healthy male subjects, $23.33{\pm}2.06$ years in age and $66.18{\pm}8.19\;kg$ in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After three capsules containing 300 mg as erdosteine were orally administered, blood was taken at predetermined time intervals and the concentations of erdosteine in serum were determined using HPLC method with UV detector. The dissolution profiles of two formulations were similar at all dissolution media. Besides, the pharmacokinetic parameters such as $AUC_t,\;C_{max}\;and\;T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t\;and\;C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the Erdos were 0.20%, 1.10% and -9.44% for $AUC_t,\;C_{max}\;and\;T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log(0.8) to log(1.25) $(e.g.,\;log(0.94){\sim}log(1.22)\;and\;log(0.92){\sim}log(1.20)\;for\;AUC_t\;and\;C_{max},\;respectively$. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Erblon capsule and Erdos capsule are bioequivalent.

• Journal of Pharmaceutical Investigation
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• v.33 no.4
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• pp.311-317
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• 2003

Felodipine is a calcium antagonist that lowers blood pressure by reducing peripheral resistance by meas of a direct, selective action on smooth muscle in arterial resistance vessels. Futhermore, it have been approved for the effective in angina pectoris and cardiac failure. The purpose of the present study was to evaluate the bioequivalence of two felodipine extended release (ER) tablets, Splendil (YuHan Corporation) and Stapin (Hana Pharmaceutial Co., Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). The felodipine release from the two felodipine formulations in vitro was tested using KP VIII Apparatus II method at pH 6.5 buffer solution. Twenty six healthy male subjects, $22.73{\pm}1.78$ years in age and $66.66{\pm}7.28\;kg$ in body weight, were divided into two groups and a radomized $2{\times}2$ cross-over study was employed. After two tablets containing 5 mg as felodipine were orally administered, blood sample was taken at predetermined time intervals and the concentrations of felodipine in serum were determined using column-switching HPLC method with UV detector. The dissolution profiles of two formulations were similar at pH 6.5 buffer solution. Besides, the pharmacokinetic parameters such as $AUC_t,\;C_{max}\;and\;T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t\;and\;C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the Splendil were 2.53%, 1.32% and 18.32% for $AUC_t,\;C_{max}\;and\;T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance rage of log(0.86) to log(1.25) $(e.g.,\;log(0.86){\sim}log(1.20)\;and\;log(0.89){\sim}log(1.23)\;for\;AUC_t,\;C_{max},\;respectively)$. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Stapin ER tablet and Splendil ER tablet are bioequivalent.

• Journal of Society of Preventive Korean Medicine
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• v.17 no.2
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• pp.139-155
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• 2013

Purpose : This study was aim to evaluate effects of pharmacodynamics and toxicity in combination therapy of donepezil with Gongjindan. The effects of Gongjindan co-administration on the pharmacokinetics (PK) of donepezil were observed after single and 7-day repeated oral co-administration with 1.5hr-intervals, to evaluate synergic pharmacodynamics and reduce toxicity of combination therapy of donepezil with Gongjindan. Materials and Methods : After 10mg/kg of donepezil treatment, Gongjindan100mg/kg was administered with 1.5hr-intervals. The plasma were collected at 30min before administration, 30min, 1, 2, 3, 4, 6, 8 and 24hrs after end of first and last 7th donepezil treatment, and plasma concentrations of donepezil were analyzed using LC-MS/MS methods. Results : Gongjindan markedly inhibited the absorption of donepezilregardless of sample time, from 30min to 8hrs after end of first 1.5hr-interval co-administration as compared with donepezil single treated rats. Especially the absorption of donepezil was significantly decreased at 2, 4, 6 and 8hrs after co-administration as compared with donepezilsingle treated rats. Accordingly, the Cmax (-26.236%), $AUC_{0-t}$(-26.02%) and $AUC_{0-inf}$(-25.90%) of donepezil in 1.5hr-interval co-administered rats were dramatically decreased as compared with donepezilsingle treated rats, respectively. However, no meaningful changes on the plasma donepezil concentrations and pharmacokinetic parameters were detected after end of last 7th 1.5hr-interval co-administration as compared with donerezil single treated rats, except for non-significant slight increases of Tmax(16.67%) detected in co-administered rats as compared with donepezil single treated rats. Conclusion : These findings are considered as direct evidences that Gongjindan also decreased oral bioavailability of donerezil as inhibited the absorptions, when they were co-administered with 1.5hr-intervals, but they may be adapted after 7 days continuous repeated l.5hr-interval co-administration.

• Journal of Pharmaceutical Investigation
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• v.35 no.1
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• pp.39-44
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• 2005

The purpose of the present study was to evaluate the bioequivalence of two cefaclor capsules, Ceclor (Lilly Korea Co., Ltd.) and Kyongbocefaclor (Kyongbo Pharm. Co., Ltd.), according to the guidelines of the Korea Food and Drug Administration (KFDA). The release of cefaclor from the two cefaclor formulations in vitro was tested using KP VIII Apparatus II method with various dissolution media (pH 1.2, 4.0, 6.8 buffer solution and water). Twenty four healthy male subjects, $22.96{\pm}1.52$ years in age and $67.03{\pm}7.90$ kg in body weight, were divided into two groups and a randomized $2{\times}2$ crossover study was employed. After one capsule containing 250 mg of cefaclor was orally administered, blood was taken at predetermined time intervals and the concentrations of cefaclor in serum were determined using HPLC method with UV detector. The dissolution profiles of two formulations were similar at all dissolution media. In addition, the pharmacokinetic parameters such as $AUC_t$, $C_{max}$ and $T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, Ceclor, were -1.90%, 2.68% and -7.60% for $AUC_t$, $C_{max}$ and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25 $(e.g.,\;log0.91{\sim}log\;1.06\;and\;log0.92{\sim}log\;1.18\;for\;AUC_t\;and\;C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Kyongbocefaclor capsule was bioequivalent to Ceclor capsule.

• Journal of Pharmaceutical Investigation
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• v.36 no.3
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• pp.201-207
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• 2006

Acetaminophen (paracetamol), a para-aminophenol derivative, has analgesic and antipyretic properties and weak anti-inflammatory activity. The purpose of the present study was to evaluate the bioequivalence of two acetaminophen tablets, $Tylenol^{\circledR}$ ER (Janssen Korea Ltd.) and Tylicol ER (Hana Pharmaceutical Co., Ltd.), according to the guidelines of the Korea Food and Drug Administration (KFDA). The release of acetaminophen from the two acetaminophen formulations in vitro was tested using KP VIll Apparatus II method with pH 1.2 buffer solution. Twenty six healthy male subjects, $22.8{\pm}1.99$ years in age and $65.6{\pm}8.03$ kg in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After a single tablet containing 650 mg as acetaminophen was orally administered, blood samples were taken at predetermined time intervals and the concentrations of acetaminophen in serum were determined using HPLC with UV detector. The dissolution profiles of two formulations were similar in pH 1.2 buffer solution. The pharmacokinetic parameters such as $AUC_t$, $C_{max}$ and $T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, $Tylenol^{\circledR}$ ER, were 2.84, 1.89 and -1.36% for $AUC_t$, $C_{max}$ and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25 (e.g., log $0.987{\sim}log$ 1.08 and log $0.944{\sim}log$ 1.17 for $AUC_t$ and $C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Tylicol ER tablet was bioequivalent to $Tylenol^{\circledR}$ ER tablet.