Objective: Prostaglandin E₂ (PGE₂) synthesis is modulated by COX2. Changes in PGE₂ could be used to quantify the COX2 inhibition after ibuprofen administration. This study investigated the pharmacokinetic and pharmacodynamic relationships for COX2 inhibition according to three formulations of ibuprofen in healthy male subjects. Materials and methods: A randomized, open-label, single-dose, three-treatment, six-sequence crossover study was performed in 36 healthy South Korean male volunteers. Enrolled subjects received the following three 200 mg ibuprofen formulations: ibuprofen arginine, solubilized ibuprofen capsule, and standard ibuprofen. Pharmacokinetic and pharmacodynamic blood samples were collected for 16 hours following treatment. For pharmacodynamic evaluations, lipopolysaccharide (LPS)-induced PGE₂ inhibition at each time point compared to predose was measured. Noncompartmental analysis was used for pharmacokinetic assessment, and time-weighted average inhibition (WAI) of PGE₂ was applied to the pharmacodynamic evaluation. Results: After a single oral dose of the ibuprofen formulations, the median times to maximum concentration were 0.42, 0.5, and 1.25 hours in ibuprofen arginine, solubilized ibuprofen capsule, and ibuprofen, respectively. The maximum observed plasma concentration was lower in ibuprofen, and the area under the plasma concentration–time curve was comparable among the three formulations. A significant difference was observed between fast-acting formulations and standard ibuprofen tablets for both maximum concentration and time taken to reach it. Individual formulations had an effect on PGE₂ WAI during the 8 hours following treatment, resulting in significantly lower WAI in standard ibuprofen: ibuprofen arginine 18.4%, solubilized ibuprofen capsule 18.4%, and standard ibuprofen 11.6%. Conclusion: Rapid absorption and higher peak concentration were observed in ibuprofen arginine and the solubilized ibuprofen capsule. Additionally, fast-acting formulations had more predominant inhibitory activity on the COX2 enzyme.

Objective: Theracurmin is a submicron dispersed formulation of curcumin, which was developed to increase the bioavailability of curcumin. This study aimed to compare the pharmacokinetics of curcumin administered as two Theracurmin powder products and unformulated curcumin powder. Materials and methods: This randomized, three-treatment, six-sequence, and three-period crossover study enrolled 24 healthy subjects. Blood sampling was done until 12 hours after the administration of Theracurmin and curcumin powder to assess pharmacokinetics using a non-compartmental method. The plasma concentration of curcumin was determined using high-performance liquid chromatography coupled with tandem mass spectrometry. Results: The median time to reach the maximum concentration was 1.5 – 3 hours for Theracurmin and 8 hours for curcumin powder. The two Theracurmin products showed systemic exposure profiles that were comparable to each other. The exposure ratio of Theracurmin to curcumin powder was 18.4 – 20.5 for the maximum plasma concentration and 35.9 – 42.6 for the area under the concentration-time curve from dosing to the last measurable time. Conclusion: In conclusion, this study showed similar systemic exposure between the two Theracurmin products. The absorption of curcumin after the administration of Theracurmin was significantly enhanced compared with curcumin powder.

Background and objective: Rosuvastatin and ezetimibe are commonly applied in lipid-lowering pharmacotherapy. However, the pharmacokinetic (PK) interaction was not clear by the coadministration of rosuvastatin and ezetimibe. This study investigated the pharmacodynamic (PD) and PK interactions between rosuvastatin and ezetimibe through a crossover clinical trial. Subjects and methods: A randomized, open-label, multiple-dose, two-treatment, two-period, two-sequence crossover study with two treatment parts was conducted in healthy male subjects. Study part A involved rosuvastatin, and study part B involved ezetimibe. A total of 25 subjects in both parts completed the PK and PD evaluations. Rosuvastatin (20 mg) or ezetimibe (10 mg) was administered once daily for 7 days as monotherapy or co-therapy. The plasma concentrations of rosuvastatin, total ezetimibe and free ezetimibe were measured for 72 h after day 7. Low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and total cholesterol (TC) were investigated for the PD assessments on day 1 (pretreatment) and day 8. Results: Rosuvastatin and ezetimibe presented multiple peaks. The 90% confidence intervals (CIs) of the geometric mean ratios for the peak plasma concentration at steady state (C_max,ss) and area under the plasma concentration–time curve during the dosing interval at steady state (AUC_t,ss) of rosuvastatin and total ezetimibe were within the range 0.8–1.25. However, the coadministration increased the systemic exposure of free ezetimibe. In the PD assessments, rosuvastatin and ezetimibe monotherapy reduced the LDL-C and TC levels effectively. In addition, the lipid-lowering effects of the coadministration corresponded to an approximate summation of the effects of rosuvastatin and ezetimibe monotherapy. However, no significant changes in HDL-C were observed with rosuvastatin or ezetimibe treatment. No significant safety issue was noted. Conclusion: The coadministration of rosuvastatin and ezetimibe revealed a bioequivalent PK interaction. Additional lipid-lowering effects, including decreased LDL-C and TC, were observed as expected in combination therapy without significant safety concern.

Variability of the drug response to nonsteroidal anti-inflammatory drugs according to cyclooxygenase-2 genetic polymorphism Sook Joung Lee,1,* Min Kyu Park,2,* Dong-Seong Shin,3 Min Ho Chun4 1Department of Physical Medicine and Rehabilitation, Dong-A University College of Medicine, Dong-A University Hospital, 2Department of Pharmacology and Clinical Pharmacology, Dong-A University College of Medicine, Dong-A University Hospital, Busan, 3Clinical Trials Center, Gachon University Gil Medical Center, Incheon, 4Department of Rehabilitation Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea *These authors contributed equally to this work Purpose: Cyclooxygenase (COX) is the main pharmacodynamic target of nonsteroidal anti-inflammatory drugs (NSAIDs). We investigated the inhibitory effects on COX-2 after NSAIDs administration using a lipopolysaccharide (LPS)-derived COX-2 induction model in whole blood, according to the genotypes of COX-2 single-nucleotide polymorphisms (SNPs). Patients and methods: Seven genotypes of COX-2 SNPs were selected from public databases and analyzed in 324 healthy subjects. Two genotypes showing a high percentage of variability were selected. A clinical trial examining pharmacodynamics according to the genotype of two SNPs (rs5275 and rs689466) was conducted. Twenty subjects were administered a single oral dose of 200 mg of celecoxib, and pharmacokinetic and pharmacodynamic analyses were performed. Results: In the analysis of the pharmacokinetic parameters, significant differences in drug exposure were not investigated for each SNP genotype. The pharmacodynamic analysis revealed that the maximum effect of COX-2 inhibition was achieved at 2.0 hours for all genotypes of COX-2 SNPs after a single oral administration of 200 mg celecoxib. The inhibitory effects according to the genotype of COX-2 SNPs were investigated, and the area under the effect curve of the rs689466 GG genotype was significantly lower than that for the AA or AG genotype. Conclusion: Our results demonstrated that inhibitory effects of celecoxib on COX-2 induction were different according to the genotype of COX-2 SNPs. In the present study, rs689466 is responsible for the variability of the response to celecoxib, suggesting that a subject with the GG genotype of rs689466 would be more responsive to celecoxib in terms of COX-2 inhibition. Keywords: nonsteroidal anti-inflammatory agent, cyclooxygenase-2, single-nucleotide polymorphism, drug response, pharmacodynamics, clinical trial

Background and objective: The effects of age and related factors on insulin sensitivity have not been definitively evaluated in East Asian populations. We proposed a reference range for the glucose disposal rate (M-value) on hyperinsulinemic-euglycemic study and its association with other parameters. Methods: Healthy, non-diabetic young (n=10) and elderly (n=13) male subjects with normal body mass index were eligible for this study. Subjects who passed the oral glucose tolerance test (OGTT) underwent hyperinsulinemic-euglycemic clamp with high-dose (80 mU/m²·min) insulin infusion. Results: M-values were normalized to body weight (M_BW) and fat-free mass (M_FFM). Neither M-value was significantly different between age groups (P=0.458 and P=0.900, respectively). An inverse correlation was observed between M_FFM and baseline insulin (r=−0.418; P=0.047), baseline C-peptide (r=−0.426; P=0.043) and OGTT 2-hour glucose (r=−0.452; P=0.030). Regarding correlations with other insulin sensitivity indices, M-values were positively associated with the Matsuda index but not with homeostasis model assessment of insulin resistance. Conclusion: Our results suggest that age is not a critical determinant of insulin sensitivity, while fasting insulin and C-peptide levels, OGTT 2-hour glucose level, and Matsuda index are predictable markers of insulin sensitivity in healthy Koreans.