Signal Detection of Adverse Event of Metoclopramide in Korea Adverse Event Reporting System (KAERS)

Background@#This study was aimed to identify the safety signals of metoclopramide in Korea Adverse Event Reporting System (KAERS) database by proportionality analysis methods. @*Methods@#The study was conducted using Korea Institute of Drug Safety and Risk Management-Korea Adverse Event Reporting System Database (KIDS-KD) reported from January 2013 to December 2017 through KAERS. Signals of metoclopramide that satisfied the data-mining indices of proportional reporting ratio (PRR), reporting odds ratio (ROR) and information component (IC) were defined. The detected signals were checked whether they included in drug labels in the Ministry of Food and Drug Safety (MFDS), U.S. Food and Drug Administration (FDA) and Micromedex® . @*Results@#A total number of drug AE reports associated with all drugs of data in this study was 2,665,429. Among them, the number of AE reports associated with metoclopramide was 22,583. Forty-two meaningful signals of metoclopramide were detected that satisfied with the criteria of data-mining indicies. Especially neurological signals including extrapyramidal reactions, represented in the safety letter of regulatory agencies were identified in this study. @*Conclusion@#Neurological signals of metoclopramide including extrapyramidal reactions were detected. It is believed that this search for signals can contribute to ensuring safety in the use of metoclopramide.

Incorporation of real-world data to a clinical trial: use of external controls

As real-world data (RWD) becomes more available and the methodology for handling RWD evolves, the use of RWD in drug development and drug approval is drawing interest. One of the ways RWD can be applied to a clinical trial is using an external control, a cohort of patients established separately serving as a control group for the clinical trial’s treatment group. Although external controls have the possibility of bias as a result of differences in baseline characteristics between the external control and experimental groups, selecting an appropriate data source and ensuring comparability through proper handling of the data can increase the utility of external controls, raising the efficiency of drug development. This article discusses several topics relevant to using external controls in clinical trials, including the definition of external control, the selection of data sources, the strategy ensuring comparability, current regulatory circumstances, and future directions.

Bioanalytical methods for the detection of duloxetine and thioctic acid in plasma using ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS)

Duloxetine and thioctic acid (TA) are standard drugs for treating diabetic neuropathy, a primary complication associated with diabetes. In this study, ultra performance liquid chromatography coupled with tandem mass spectrometry methods was successfully developed and validated for quantifying duloxetine and TA in biological samples. The protein precipitation method was used to extract duloxetine, TA and their internal standards from beagle dog plasma. A Hypersil Gold C18 column (150 × 2.1 mm, 1.9 μm) was used for the experiment. Isocratic elution with 0.1% formic acid in acetonitrile (A) and 0.1% formic acid (B) was used for duloxetine, whereas a gradient elution with 0.03% acetic acid (A) and acetonitrile (B) was used for TA. The validated parameters included linearity, sensitivity, accuracy, precision, selectivity, matrix effect, stability, and recovery under different conditions. The linear ranges of the calibration curves for duloxetine and TA were 5–800 ng/mL and 5–1,000 ng/mL, respectively. An intra- and inter-run precision of ± 15% can be observed in all quality control samples. These methods were successfully used for pharmacokinetics (PKs) studies in beagle dogs to compare PK differences in a fixed-dose combination including duloxetine and TA and co-administration of the 2 drugs.

Predicting the systemic exposure and lung concentration of nafamostat using physiologically-based pharmacokinetic modeling

Nafamostat has been actively studied for its neuroprotective activity and effect on various indications, such as coronavirus disease 2019 (COVID-19). Nafamostat has low water solubility at a specific pH and is rapidly metabolized in the blood. Therefore, it is administered only intravenously, and its distribution is not well known. The main purposes of this study are to predict and evaluate the pharmacokinetic (PK) profiles of nafamostat in a virtual healthy population under various dosing regimens. The most important parameters were assessed using a physiologically based pharmacokinetic (PBPK) approach and global sensitivity analysis with the Sobol sensitivity analysis. A PBPK model was constructed using the SimCYP® simulator. Data regarding the in vitro metabolism and clinical studies were extracted from the literature to assess the predicted results. The model was verified using the arithmetic mean maximum concentration (Cmax), the area under the curve from 0 to the last time point (AUC0-t), and AUC from 0 to infinity (AUC0-∞) ratio (predicted/observed), which were included in the 2-fold range. The simulation results suggested that the 2 dosing regimens for the treatment of COVID-19 used in the case reports could maintain the proposed effective concentration for inhibiting severe acute respiratory syndrome coronavirus 2 entry into the plasma and lung tissue. Global sensitivity analysis indicated that hematocrit, plasma half-life, and microsomal protein levels significantly influenced the systematic exposure prediction of nafamostat. Therefore, the PBPK modeling approach is valuable in predicting the PK profile and designing an appropriate dosage regimen.

Physiologically-based pharmacokinetic model for clozapine in Korean patients with schizophrenia

Clozapine has been used as a treatment of schizophrenia. Despite its large interindividual variability, few reports addressed the physiologically-based pharmacokinetic modeling and simulation (PBPK M&S) of clozapine in patients. This study aimed to develop a PBPK M&S of clozapine in Korean patients with schizophrenia. PBPK modeling for clozapine was constructed using a population-based PBPK platform, the SimCYP® Simulator (V19;Certara, Sheffield, UK). The PBPK model was developed by optimizing the physiological parameters of the built-in population and compound libraries in the SimCYP® Simulator. The model verification was performed with the predicted/observed ratio for pharmacokinetic parameters and visual predictive checks (VPCs) plot. Simulations were performed to predict toxicities according to dosing regimens. From published data, 230 virtual trials were simulated for each dosing regimen. The predicted/observed ratio for the area under the curve and peak plasma concentration was calculated to be from 0.78 to 1.34. The observation profiles were within the 5th and 95th percentile range with no serious model misspecification through the VPC plot. A significant impact on age and gender was found for clozapine clearance. The simulation results suggested that 150 mg twice a day and 150 mg three times a day of clozapine have toxicity concerns. In conclusion, a PBPK model was developed and reasonable parameters were made from the data of Korean patients with schizophrenia. The provided model might be used to predict the pharmacokinetics of clozapine and assist dose adjustment in clinical settings.

Determination of candesartan or olmesartan in hypertensive patient plasma using UPLC-MS/MS

Candesartan and olmesartan are angiotensin II receptor blockers (ARBs) used for the treatment of hypertension and heart failure. Quantitation methods for candesartan and olmesartan were developed using ultra-high performance liquid chromatography-tandem mass spectrometry following protein precipitation. Candesartan was separated using 5 mM ammonium formate (A) and 100% acetonitrile (B) and olmesartan was separated using 2 mM ammonium formate with 0.1% formic acid (A) and 100% acetonitrile (B). Separation was performed using an isocratic method with a Thermo hypersil GOLD C18 column. Electrospray ionization was used for analyte ionization and detection of candesartan, olmesartan, and the internal standards by multiple reaction monitoring. Developed method showed excellent linearity (r > 0.99) in the concentration range of 2–500 ng/mL for candesartan and 5–2,500 ng/mL for olmesartan. were 86.70–108.8% for candesartan and 87.87–112.6% for olmesartan. These methods were able to successfully measure plasma candesartan or olmesartan concentrations in hypertensive patients. This study can be used for pharmacokinetic studies of candesartan or olmesartan in humans.

Signal Detection for Adverse Events of Finasteride Using Korea Adverse Event Reporting System (KAERS) Database

To investigate signals of adverse drug reactions of finasteride by using the Korea Adverse Events Reporting System (KAERS) database. This pharmacovigilance was based on the database of the drug-related adverse reactions reported spontaneously to the KAERS from 2013 to 2017. This study was conducted by disproportionality analysis. Data mining analysis was performed to detect signals of finasteride. The signal was defined by three criteria as proportional reporting ratio (PRR), reporting odds ratio (ROR), and information component (IC). The signals of finasteride were compared with those of the other drugs; dutasteride (similar mechanism of action), minoxidil (different mechanism but similar indications for alopecia), silodosin (different mechanism but similar indications for BPH). It was examined whether the detected signals exist in drug labels in Korea. The total number of adverse eventdrug pairs was reported 2,665,429 from 2013 to 2017, of which 1,426 were associated with finasteride. The number of investigated signals of finasteride was 42. The signals that did not include in the drug label were 29 signals, including mouth dry, hypotension, dysuria etc. The signal of finasteride was similar to that of dutasteride and silodosin but was different to that of minoxidil. Early detection of signals through pharmacovigilance is important to patient safety. We investigated 29 signals of finasteride that do not exist in drug labels in Korea. Further pharmacoepidemiological studies should be needed to evaluate the signal causality with finasteride.

Quantification of apixaban in human plasma using ultra performance liquid chromatography coupled with tandem mass spectrometry

Apixaban, an inhibitor of direct factor Xa, is used for the treatment of venous thromboembolic events or prevention of stroke. Unlike many other anticoagulant agents, it does not need periodic monitoring. However, monitoring is still required to determine the risk of bleeding due to overdose or surgery. Usually, apixaban concentrations are indirectly quantified using an anti-factor Xa assay. However, this method has a relatively narrow analytical concentration range, poor selectivity, and requires an external calibrator. Therefore, the goal of current study was to establish an analytical method for determining plasma levels of apixaban using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). To this end, apixaban was separated using 2.5 mM ammonium formate (pH 3.0) (A) and 100% methanol containing 0.1% formic acid (B) using the gradient method with a Thermo hypersil GOLD column. The mass detector condition was optimized using the electrospray ionization (ESI) positive mode for apixaban quantification. The developed method showed sufficient linearity (coefficient of determination [r² ≥ 0.997]) at calibration curve ranges. The percentage (%) changes in accuracy, precision, and all stability tests were within 15% of the nominal concentration. Apixaban concentration in plasma from healthy volunteers was quantified using the developed method. The mean maximum plasma concentration (C(max)) was 371.57 ng/mL, and the median time to achieve the C(max) (T(max)) was 4 h after administration of 10 mg apixaban alone. Although the results showed low extraction efficiency (~16%), the reproducibility (% change was within 15% of nominal concentration) was reliable. Therefore, the developed method could be used for clinical pharmacokinetic studies.

Survey on the undergraduate curriculum in clinical pharmacology and interns' prescribing ability in South Korea

Appropriate prescription writing is one of the critical medical processes affecting the quality of public health care. However, this is a complex task for newly qualified intern doctors because of its complex characteristics requiring sufficient knowledge of medications and principles of clinical pharmacology, skills of diagnosis and communication, and critical judgment. This study aims to gather data on the current status of undergraduate prescribing education in South Korea. Two surveys were administered in this study: survey A to 26 medical schools in South Korea to gather information on the status of undergraduate education in clinical pharmacology; and survey B to 244 intern doctors in large hospitals to gather their opinions regarding prescribing education and ability. In survey A, half of the responding institutions provided prescribing education via various formats of classes over two curriculums including lecture, applied practice, group discussions, computer-utilized training, and workshops. In survey B, we found that intern doctors have the least confidence when prescribing drugs for special patient populations, especially pregnant women. These intern doctors believed that a case-based practical training or group discussion class would be an effective approach to supplement their prescribing education concurrently or after the clerkship in medical schools or right before starting intern training with a core drug list. The results of the present study may help instructors in charge of prescribing education when communicating and cooperating with each other to improve undergraduate prescribing education and the quality of national medical care.

Development of a UPLC-MS/MS method for the therapeutic monitoring of L-asparaginase

This study aimed to develop a UPLC-MS/MS method for determining plasma levels of L-aspartic acid and L-asparagine and the activity of L-asparaginase. L-aspartic acid, L-asparagine, and L-aspartic acid-2,3,3-d3 were extracted from human plasma by protein precipitation with sulfosalicylic acid (30%, v/v). The plasma samples were analyzed using an Imtakt Intrada amino acid analysis column with 25 mM ammonium formate and 0.5% formic acid in acetonitrile as the mobile phase with step gradient method at a flow rate of 0.5 mL/min. The injection volume was 5 µL, and the total run time was 15 min. Inter- and intra-batch accuracies (%) ranged from 96.62–106.0% for L-aspartic acid and 89.85–104.8%, for L-asparagine, and the coefficient of variation (CV%) did not exceed 7%. The validation results for L-aspartic acid and L-asparagine satisfied the specified criterion, however, the results for L-asparaginase activity assay showed a borderline validity. This study could be a foundation for further development of therapeutic drug monitoring systems using UPLC-MS/MS.

Determination of donepezil in human plasma using ultra performance liquid chromatography-tandem mass spectrometry

An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantification of donepezil in human plasma. Donepezil and donepezil-D4 were extracted from human plasma by liquid-liquid extraction using a mixture of hexane and ethyl acetate (70:30 v/v). The extracted samples were analyzed using a Thermo Hypersil Gold C18 column with 5% acetic acid in 20 mM ammonium acetate buffer (pH 3.3) and 100% acetonitrile as a mobile phase with the 60:40 (v:v) isocratic method, at a flow rate of 0.3 mL/min. The injection volume was 3 µL, and the total run time was 3 min. Inter- and intra-batch accuracies ranged from 98.0% to 110.0%, and the precision was below 8%. The developed method was successfully applied to the quantification of donepezil in human plasma. The mean (standard deviation) maximum concentration and the median (range) time to maximum concentration were 8.6 (2.0) ng/mL and 2.0 h (1.0~5.0 h), respectively, in healthy Koreans after oral administration of 5 mg donepezil.

A Case of Diabetic Ketoacidosis Caused by Dapsone-Induced Acute Pancreatitis / 임상당뇨병

Drug-induced pancreatitis accounts for 0.1~2.0% of all pancreatitis cases. Generally, the mechanism of drug-induced pancreatitis is an immune reaction, accumulation of toxic material, and/or ischemia. However, how dapsone causes pancreatitis remains unclear. A 61-year-old man presented with a 2-week history of epigastric discomfort. He had taken dapsone for 2 months to treat psoriasis. Laboratory findings showed high blood glucose levels and metabolic acidosis; however, hemoglobin A1c was low. Serum amylase and lipase levels were elevated to 125/4,479 U/L. Abdominal computed tomography was indicative of pancreatitis. There was no causative history of pancreatitis and no other medication history except dapsone. Thus, we reached a diagnosis of diabetic ketoacidosis (DKA) followed by dapsone-induced pancreatitis. The patient fasted and was treated with insulin administration and fluid hydration in accordance with treatment guidelines. After treatment, amylase and lipase decreased and symptoms subsided, but insulin injection was required to control blood glucose levels. Drug-induced pancreatitis is a very rare adverse effect of dapsone. Only four cases of pancreatitis related to dapsone could be found in a PubMed search. Moreover, diabetes caused by dapsone-induced pancreatitis has not been reported previously. Here, we report a case of DKA caused by dapsoneinduced acute pancreatitis.

Population Pharmacokinetics of Midazolam in Healthy Koreans: Effect of Cytochrome P450 3A-mediated Drug-drug Interaction

OBJECTIVE: Midazolam is mainly metabolized by cytochrome P450 (CYP) 3A. Inhibition or induction of CYP3A can affect the pharmacological activity of midazolam. The aims of this study were to develop a population pharmacokinetic (PK) model and evaluate the effect of CYP3A-mediated interactions among ketoconazole, rifampicin, and midazolam. METHODS: Three-treatment, three-period, crossover study was conducted in 24 healthy male subjects. Each subject received 1 mg midazolam (control), 1 mg midazolam after pretreatment with 400 mg ketoconazole once daily for 4 days (CYP3A inhibition phase), and 2.5 mg midazolam after pretreatment with 600 mg rifampicin once daily for 10 days (CYP3A induction phase). The population PK analysis was performed using a nonlinear mixed effect model (NONMEM® 7.2) based on plasma midazolam concentrations. The PK model was developed, and the first-order conditional estimation with interaction was applied for the model run. A three-compartment model with first-order elimination described the PK. The influence of ketoconazole and rifampicin, CYP3A5 genotype, and demographic characteristics on PK parameters was examined. Goodness-of-fit (GOF) diagnostics and visual predictive checks, as well as bootstrap were used to evaluate the adequacy of the model fit and predictions. RESULTS: Twenty-four subjects contributed to 900 midazolam concentrations. The final parameter estimates (% relative standard error, RSE) were as follows; clearance (CL), 31.8 L/h (6.0%); inter-compartmental clearance (Q) 2, 36.4 L/h (9.7%); Q3, 7.37 L/h (12.0%), volume of distribution (V) 1, 70.7 L (3.6%), V2, 32.9 L (8.8%); and V3, 44.4 L (6.7%). The midazolam CL decreased and increased to 32.5 and 199.9% in the inhibition and induction phases, respectively, compared to that in control phase. CONCLUSION: A PK model for midazolam co-treatment with ketoconazole and rifampicin was developed using data of healthy volunteers, and the subject's CYP3A status influenced the midazolam PK parameters. Therefore, a population PK model with enzyme-mediated drug interactions may be useful for quantitatively predicting PK alterations.

A Detailed Analysis of Alcohol Pharmacokinetics in Healthy Korean Men / 대한법의학회지

To determine blood alcohol concentration (BAC) by extrapolation, an understanding of basal pharmacokinetics is indispensable. Breath alcohol concentration (BrAC) has been used for the determination of body alcohol concentration replaced by BAC in Korea. Therefore, the determination of BAC/BrAC ratio is a key problem in alcohol pharmacokinetics. Among several factors, the ingested dose of alcohol and the allelic variation of mitochondrial aldehyde dehydrogenase 2 (ALDH2) are the most significant factors influencing the pharmacokinetic parameters, particularly in the absorption and elimination phases. This study shows a detailed pharmacokinetic analysis of BAC and BrAC associated with genetic polymorphism including ALDH2 in 42 healthy Korean men. The change in the alcohol dose ingested influenced the maximum concentration (C(max)), the time to reach C(max) (T(max)), the absorption rate constant (K(01)), the area under the concentration-time curve (AUC(last)), and the hourly elimination rate. The conversion of wild-type 487Glu (ALDH2*1) to 487Lys (ALDH2*2) in human ALDH2 resulted in changes in C(max) (ALDH2*1/*1, 0.03+/-0.01 g/dL [+/-standard deviation] vs. ALDH2*1/*2, 0.05+/-0.004 g/dL [P<0.01]), AUC(last) (ALDH2*1/*1, 4.48+/-2.19 g.min/dL vs. ALDH2*1/*2, 7.52+/-1.26 g.min/dL [P<0.05]), and the BAC elimination rate (ALDH2*1/*1, 0.05+/-0.02 g/L/hr vs. ALDH2*1/*2, 0.09+/-0.01 g/L/hr [P<0.05]). Moreover, the comparison of BAC and BrAC by Bland-Altman plot showed good agreement, suggesting that the measurement of BrAC can be a good alternative for the determination of BAC, particularly in the post-absorption phase. These results provide fundamental information about the pharmacokinetics of alcohol and the determination of BAC in forensics.

Pharmacokinetic Characteristics of Cefcapene Pivoxil Hydrochloride after Single Oral Administration in Healthy Korean Subjects

BACKGROUND: Cefcapene pivoxil hydrochloride (CFPN-PI) is an oral ester cephalosporin antibiotic with a broad spectrum. In this study, we investigated the pharmacokinetics (PK) and tolerability of CFPN-PI following single oral administration in healthy Korean subjects. METHODS: An open label, dose escalation, parallel group study was conducted in 18 healthy male volunteers. A single dose of CFPN-PI was administered to 6 subjects in each treatment group of 100, 150 and 200 mg. Serial blood and urine samples were collected up to 12 h and 24 h after dosing, respectively. Plasma and urine concentrations of cefcapene were measured by HPLC-UV. PK parameters were estimated using non-compartmental analysis. For the safety evaluation, adverse event monitoring, clinical laboratory tests and physical examination were performed throughout the study. RESULTS: Median values of time to peak plasma concentration were observed around 1.5 to 2.0 h. Maximum plasma concentrations (Cmax) were 1.04 +/- 0.22, 1.24 +/- 0.46 and 1.56 +/- 0.43 mg/L (mean +/- SD), and area under the plasma concentration time curve (AUCinf) were 2.94 +/- 0.46, 3.97 +/- 1.28 and 4.70 +/- 1.19 h*mg/L in 100, 150 and 200 mg dose groups, respectively. The differences of dose normalized Cmax and AUCinf among three groups were not statistically significant. The fractions of drug excreted in urine unchanged were 31.5 % - 42.9 %. There were no serious adverse events or clinically significant abnormalities related to CFPN-PI. CONCLUSION: CFPN-PI was well tolerated with single oral administration and showed a linear PK property within 100 - 200 mg in healthy Korean male subjects.

Pharmacokinetics and Tolerability Evaluation of Fudosteine after Oral Administration in Healthy Korean Volunteers

BACKGROUND: Fudosteine, (-)-(R)-2-amino-3-(3-hydroxypropylthio)propionic acid, is a cysteine derivative that was approved in Japan, as a new mucoactive agent. The aim of this study was to evaluate the tolerability and pharmacokinetics (PK) of fudosteine in healthy Korean subjects. METHODS: A randomized, open-label, parallel, escalating single-dose study was conducted in 16 healthy Korean male subjects. The subjects were allocated to single-dose groups of 400 or 800 mg. Serial blood samples for PK analysis were collected immediately prior and after dosing up to 24 hours, and plasma concentrations were determined by high performance liquid chromatography (HPLC). Safety profiles were evaluated by monitoring adverse events and clinical evaluations throughout the study. RESULTS: Median time to peak concentration (Tmax) of both dosing group were around 0.5 hours and half-life (t1/2) were around 3 hours. Mean peak concentration (Cmax) of 400 mg and 800 mg dosing group were 10.8 and 21.5 microg/mL and the mean area under the plasma concentration versus time curve from the dosing time to infinity (AUCinf) were 26.8 and 55.0 microg.h/mL, respectively. Mean dose-normalized Cmax were 0.0271 and 0.0269 microg/mL/mg (P=0.923), respectively and dose-normalized AUCinf were 0.0669 and 0.0688 microg.hr/mL/mg (P=0.093), respectively. Fudosteine was well tolerated without any serious adverse events or clinical laboratory abnormalities. CONCLUSION: This study showed that fudosteine has a linear PK property and is well tolerated within 800 mg in healthy Korean volunteers.

Pharmacokinetics and Tolerability Evaluation of Human Coagulation Recombinant Factor VIII (GreenGene(TM)) in Hemophilia A Patients

BACKGROUND: GreenGene(TM) (Green Cross Corp.) is a recombinant clotting factor VIII which is used for hemophilia A. This study aimed to investigate the pharmacokinetics and safety profiles of 25 IU/kg and 50 IU/kg of GreenGene(TM) in Korean hemophilia A patients. METHODS: A dose-block randomized, single-blind, active drug-controlled, single and multiple dose, parallel-group study was conducted with 16 hemophilia A patients (25 IU/kg: 50 IU/kg = 8:8). They received GreenGene(TM) or GreenMono(TM)(active control) intravenously on day 1 and every other day from day 4 to 10. FVIII:C (Factor VIII procoagulant activity) was measured to determine the pharmacokinetics (PK) at baseline and up to 48 hours for single and multiple administration. PK parameters were determined using noncompartmental methods. RESULTS: The maximum concentration (Cmax) and the area under the concentration-time curve (AUC0-48) of the GreenGene(TM) 25 IU/kg (mean +/- SD) were 59.00 +/- 19.26 % and 774.40 +/- 380.13 %.h respectively, while those of 50 IU/kg were 131.50 +/- 39.81 % and 1462.44 +/- 397.09 %.h after single administration. The Cmax and AUC0-48 in steady state of the GreenGene(TM) 25 IU/kg were 68.17 +/- 22.75 % and 863.30 +/- 334.40 %.h, while those of 50 IU/kg were 147.17 +/- 18.47 % and 1820.08 +/- 704.42 %.h. No serious adverse event was observed. CONCLUSION: The GreenGene(TM) to hemophilia A patients appeared to be well tolerated within range of 25-50 IU/kg. The PK parameters of factor VIII showed dose-independent manner with 25 IU/kg and 50 IU/kg dose ranges.