• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.84-87
• /
• 2003

The purposes of this study were to evaluate the population pharmacokinetics of levosulpiride and terbinafine according to several pharmacokinetic models and to investigate the influence of characteristics of subjects such as age, body weight, height and serum creatinine concentration on the pharmacokinetic parameters of levosulpiride and terbinafine, respectively. (omitted)

• Journal of Pharmaceutical Investigation
• /
• v.39 no.4
• /
• pp.233-242
• /
• 2009

Bioequivalence (BE) studies provide important information in the overall set of data that ensure the availability of safe and effective medicines to patients and practitioners. Thus its determination of proper criterion for assessing BE is very important. BE is frequently expressed or measured by estimating area under the plasma concentration-time curve (AUC) and maximum concentration ($C_{max}$) that are reflective of systemic exposure. In all countries except Canada, the acceptance criteria of BE is that the 90% confidence interval of difference in the average values of logarithmic AUC and $C_{max}$ between test and reference products is within the acceptable range of log(0.8) ${\sim}$ log(1.25). In Canada, unlike other countries, point estimation instead of applying 90% confidence interval is applied to assess $C_{max}$ which is, in essence, more variable than AUC. We also compared other parts of BE guidelines which include a fed study, average BE (ABE), scaled-ABE, population BE (PBE), individual BE (IBE), dropout & withdrawal, sampling frequency & time and number of subjects. This article reviews the most recent BE guidelines of Korea, USA, Europe, Canada and Japan, highlighting the differences focused on Korean BE guidelines compared to other countries. It will help us to revise BE guideline of Korea reflecting international trends. Finally, it is strongly recommended that the extended acceptance criterion for the highly variable drug among all the considering aspects for the revision of current BE guideline has to be adopted into Korea BE guideline in the nearest future.

• Journal of Pharmaceutical Investigation
• /
• v.39 no.5
• /
• pp.345-351
• /
• 2009

Organic cation transporters (OCTs) are important for absorption, elimination of many endogenous small organic cations as well as a wide array of drugs and environmental toxins. This gene is located in a cluster on chromosome 6 and OCTs are in major organs such as intestine, liver, kidney, brain and placenta. Therefore, expression levels and function of OCTs directly affect plasma levels and intracellular concentrations of drugs and thereby determine therapeutic response. The aim of this study was to investigate the frequency of the SNPs on OCT1 (C181T and C1022T) and OCT2 (G808T) to analyze haplotype frequency in healthy Korean population. Human subjects have been genotyped for OCT1 (C181T for 195 subjects and C1022T for 825 subjects), using polymerase chain reaction-based diagnostic tests (RFLP). And for OCT2 (G808T), a total of 861 subjects have been genotyped, using pyrosequencing method. Haplotype was statistically inferred using an algorithm based on the expectation-maximization (EM). OCT1 C181T genotyping showed 100% homozygous wild-type (C/C). OCT1 C1022T genotyping showed wild-type (C/C), heterozygous (C/T) and homozygous mutant-type (T/T) and each accounted for 72.1, 24.5 and 3.4%, respectively. OCT2 G808T genotyping results also showed homozygous wild-type (G/G), heterozygous (G/T) and homozygous mutant-type (T/T) and each took 81.8, 17.9 and 0.3%, respectively. Based on these genotype data, haplotype analysis between OCT1 C181T and OCT1 C1022T has proceeded. The result has revealed that linkage disequilibrium between alleles is not obvious (P=0.0122).

• Journal of Pharmaceutical Investigation
• /
• v.39 no.6
• /
• pp.411-416
• /
• 2009

The aim of this study was to investigate the frequency of the SNPs on PEPT1 exon 5 and 16 and to analyze haplotype frequency on PEPT1 exon 5 and 16 in Korean population. A total of 519 healthy subjects was genotyped for PEPT1, using pyrosequencing analysis and polymerase chain reaction-based diagnostic tests. Haplotype was statistically inferred using an algorithm based on the expectation-maximization (EM). PEPT1 exon 5 G381A genotyping revealed that the frequency for homozygous wild-type (G/G), heterozygous (G/A) and homozygous mutant-type (A/A) was 30.4, 53.4 and 16.2%, respectively. PEPT1 exon 16 G1287C genotyping revealed that the frequency for homozygous G/G, heterozygous G/C and homozygous C/C type was 88.8, 10.0 and 1.2%, respectively. Based on these genotype data, haplotype analysis between PEPT1 exon 5 G381A and exon 16 G1287C using HapAnalyzer and PL-EM has proceeded. The result has revealed that linkage disequilibrium between alleles is not obvious (|D'|=0.3667).

• The Korean Journal of Physiology and Pharmacology
• /
• v.15 no.2
• /
• pp.67-81
• /
• 2011

Epilepsy is a chronic disease occurring in approximately 1.0% of the world's population. About 30% of the epileptic patients treated with availably antiepileptic drugs (AEDs) continue to have seizures and are considered therapy-resistant or refractory patients. The ultimate goal for the use of AEDs is complete cessation of seizures without side effects. Because of a narrow therapeutic index of AEDs, a complete understanding of its clinical pharmacokinetics is essential for understanding of the pharmacodynamics of these drugs. These drug concentrations in biological fluids serve as surrogate markers and can be used to guide or target drug dosing. Because early studies demonstrated clinical and/or electroencephalographic correlations with serum concentrations of several AEDs, It has been almost 50 years since clinicians started using plasma concentrations of AEDs to optimize pharmacotherapy in patients with epilepsy. Therefore, validated analytical method for concentrations of AEDs in biological fluids is a necessity in order to explore pharmacokinetics, bioequivalence and TDM in various clinical situations. There are hundreds of published articles on the analysis of specific AEDs by a wide variety of analytical methods in biological samples have appears over the past decade. This review intends to provide an updated, concise overview on the modern method development for monitoring AEDs for pharmacokinetic studies, bioequivalence and therapeutic drug monitoring.

• Journal of Pharmaceutical Investigation
• /
• v.38 no.6
• /
• pp.365-372
• /
• 2008

The aim of this study was to investigate the frequency of the SNPs on MDR1 exon 12, 21 and 26 in Korean population and to analyze haplotype frequency on MDR1 exon 12, 21 and 26 in Korean population. A total of 426 healthy subjects was genotyped for MDR1, using polymerase chain reaction-based diagnostic tests. Haplotype was statistically inferred using an algorithm based on the expectation-maximization (EM). MDR1 C1236T genotyping revealed that the frequency for homozygous wild-type (C/C), heterozygous (C/T) and for homozygous mutant-type (T/T) was 20.19%, 46.48% and 33.33%, respectively. MDR1 G2677T/A genotyping revealed that the frequency for homozygous G/G, heterozygous G/T, homozygous T/T, heterozygous G/A, heterozygous T/A and for homozygous A/A type was 30.75%, 42.26%, 9.86%, 7.51 %, 7.04% and 2.58%, respectively. MDR1 C3435T genotyping revealed that the frequency for homozygous wild-type (C/C), heterozygous (C/T) and for homozygous mutant-type (T/T) was 38.73%, 50.24% and 11.03%, respectively. Twelve haplotypes were observed. Of the three major haplotypes identified (CGC, TTT and TGC), the CGC haplotype were mainly predominant in the Korean populations and accounted for 29.96% of total haplotype in Korean.

• Korean Journal of Clinical Pharmacy
• /
• v.27 no.2
• /
• pp.105-112
• /
• 2017

Background: Generic medications are approved on the basis of bioequivalence with brand medications in healthy volunteers rather than the target population, there remains a substantial uncertainty regarding their clinical effectiveness and safety. The object of this paper is to compare the clinical equivalence of generic statin drugs in patients. Methods: Literature published before September 2016, which is indexed in PubMed, EMBASE, RISS, comparing generic to brand products in statins. Outcomes included blood lipid level, proportion of days covered (adherence), hospitalization and mortality. Results: 511 citations were screened, of which 11 studies met eligibility criteria (6 randomized clinical trials, 5 observational studies). Generic atorvastatin was clinical equivalent with brand drugs in blood lipid level (3 RCTs) and generic simvastatin was also clinical equivalent with brand drugs (2 RCTs). 2 of 3 studies reported no significant difference in proportion of days covered except 1 study which reported generic statin significantly enhance proportion of days covered (p<0.001). Hospitalization was no significant difference in all studies (p>0.05). 1 study reported that all cause of mortality was significantly low in generic drugs (p<0.0001). Conclusion: Published data on comparing clinical efficacy of generic and brand statins were insufficient in both quantity and quality. This systematic review suggests that additional studies on clinical equivalence and safety of generic medications in patients would be needed.