Regeneration of Nonhuman Primate Hearts With Human Induced Pluripotent Stem Cell-Derived Cardiac Spheroids.

BACKGROUND: The clinical application of human induced pluripotent stem cell-derived cardiomyocytes (CMs) for cardiac repair commenced with the epicardial delivery of engineered cardiac tissue; however, the feasibility of the direct delivery of human induced pluripotent stem cell-derived CMs into the cardiac muscle layer, which has reportedly induced electrical integration, is unclear because of concerns about poor engraftment of CMs and posttransplant arrhythmias. Thus, in this study, we prepared purified human induced pluripotent stem cell-derived cardiac spheroids (hiPSC-CSs) and investigated whether their direct injection could regenerate infarcted nonhuman primate hearts. METHODS: We performed 2 separate experiments to explore the appropriate number of human induced pluripotent stem cell-derived CMs. In the first experiment, 10 cynomolgus monkeys were subjected to myocardial infarction 2 weeks before transplantation and were designated as recipients of hiPSC-CSs containing 2×107 CMs or the vehicle. The animals were euthanized 12 weeks after transplantation for histological analysis, and cardiac function and arrhythmia were monitored during the observational period. In the second study, we repeated the equivalent transplantation study using more CMs (6×107 CMs). RESULTS: Recipients of hiPSC-CSs containing 2×107 CMs showed limited CM grafts and transient increases in fractional shortening compared with those of the vehicle (fractional shortening at 4 weeks after transplantation: 26.2±2.1%; 19.3±1.8%; P<0.05), with a low incidence of posttransplant arrhythmia. Transplantation of increased dose of CMs resulted in significantly greater engraftment and long-term contractile benefits (fractional shortening at 12 weeks after transplantation: 22.5±1.0%; 16.6±1.1%; P<0.01, left ventricular ejection fraction at 12 weeks after transplantation: 49.0±1.4%; 36.3±2.9%; P<0.01). The incidence of posttransplant arrhythmia slightly increased in recipients of hiPSC-CSs containing 6×107 CMs. CONCLUSIONS: We demonstrated that direct injection of hiPSC-CSs restores the contractile functions of injured primate hearts with an acceptable risk of posttransplant arrhythmia. Although the mechanism for the functional benefits is not fully elucidated, these findings provide a strong rationale for conducting clinical trials using the equivalent CM products.

Effect of Enoxaparin and Daikenchuto Coadministration on Hepatic Disorder Markers in Gynecological Cancer Patients after Abdominal Surgery.

Enoxaparin and daikenchuto are commonly administered to prevent venous thromboembolism and intestinal obstruction after gynecological malignancy surgery. However, the effects of their combined use on hepatic function are not well studied. This study aimed to clarify the effects of the coadministration of enoxaparin and daikenchuto on hepatic function. First, Japanese Adverse Drug Event Report (JADER) data were analyzed to identify signals of hepatic disorders. Second, a retrospective observational study of patients who underwent surgery for gynecological malignancies was conducted. This study defined hepatic disorders as an increase in aspartate aminotransferase (AST) or alanine aminotransaminase (ALT) levels above the reference values, using 1-h postoperative values as the baseline. The analysis of JADER data revealed an increased risk for hepatic disorders with the coadministration of enoxaparin and daikenchuto. An observational study also showed higher odds ratios (95% confidence intervals) for the occurrence of hepatic disorders in the coadministration group (4.27; 2.11-8.64) and enoxaparin alone group (2.48; 1.31-4.69) than in the daikenchuto alone group. The median increase in the ALT level was also higher in the coadministration group (34; 15-59) than in the enoxaparin alone (19; 6-38) and daikenchuto alone groups (8; 3-33). In conclusion, our study suggests that compared with the use of enoxaparin or daikenchuto alone, enoxaparin and daikenchuto coadministration increases the risk of hepatic disorders, with more significant increases in AST and ALT levels. Healthcare workers need to be aware of these potential side effects when combining these drugs after surgery for gynecological malignancies.

Intracoronary transplantation of pluripotent stem cell-derived cardiomyocytes: Inefficient procedure for cardiac regeneration.

Advances in stem cell biology have facilitated cardiac regeneration, and many animal studies and several initial clinical trials have been conducted using human pluripotent stem cell-derived cardiomyocytes (PSC-CMs). Most preclinical and clinical studies have typically transplanted PSC-CMs via the following two distinct approaches: direct intramyocardial injection or epicardial delivery of engineered heart tissue. Both approaches present common disadvantages, including a mandatory thoracotomy and poor engraftment. Furthermore, a standard transplantation approach has yet to be established. In this study, we tested the feasibility of performing intracoronary administration of PSC-CMs based on a commonly used method of transplanting somatic stem cells. Six male cynomolgus monkeys underwent intracoronary administration of dispersed human PSC-CMs or PSC-CM aggregates, which are called cardiac spheroids, with multiple cell dosages. The recipient animals were sacrificed at 4 weeks post-transplantation for histological analysis. Intracoronary administration of dispersed human PSC-CMs in the cynomolgus monkeys did not lead to coronary embolism or graft survival. Although the transplanted cardiac spheroids became partially engrafted, they also induced scar formation due to cardiac ischemic injury. Cardiac engraftment and scar formation were reasonably consistent with the spheroid size or cell dosage. These findings indicate that intracoronary transplantation of PSC-CMs is an inefficient therapeutic approach.

Characterization of plasma daptomycin in patients with serum highly glycated albumin and obesity.

PURPOSE: Plasma daptomycin has not been fully characterized in diabetic and obese patients. This study aimed to evaluate the associations of plasma daptomycin with glycation of serum albumin and obesity. METHODS: Infectious patients (n = 70) receiving intravenous daptomycin were enrolled. The plasma concentration of total and free daptomycin were determined using liquid chromatograph-tandem mass spectrometer. The associations of the plasma concentrations of daptomycin with clinical factors including serum albumin fractionations and physical status (obese including overweight, body mass index ≥ 25.0) were investigated. Daptomycin doses were adjusted using total body-weight. RESULTS: The serum albumin level was positively and negatively correlated with the plasma concentration of total daptomycin and its free fraction proportion, respectively. The serum non-glycated albumin was negatively correlated with the free fraction proportion. The dose-normalized plasma concentration of total daptomycin was higher in the obese patients than in non-obese patients when the body-weight was corrected with total and adjusted values. For the dose adjustment with lean body-weight, no difference was observed in the dose-normalized plasma concentration of total daptomycin between the physical statuses. For each body-weight correction method, physical status did not affect the dose-normalized plasma concentration of free daptomycin. CONCLUSION: The glycation of serum albumin and obesity did not associate with dose-normalized plasma free daptomycin. In obese patients, daptomycin dosage adjustment with total body-weight and adjusted body-weight may lead to an apparent excessive exposure resulting in overdosage compared to lean body-weight.

Characterization of endogenous markers of hepatic function in patients receiving itraconazole treatment for prophylaxis of deep mycosis.

BACKGROUND: Long-term use of itraconazole (ITZ) is associated with a risk of inducing hepatotoxicity. This study aimed to evaluate the associations of plasma concentrations of ITZ and its hydroxylated metabolite (OH-ITZ) with endogenous markers of hepatic function. METHODS: Thirty six patients treated with oral ITZ solution for prophylaxis of deep mycosis were enrolled. Plasma concentrations of ITZ and OH-ITZ were determined on the 14th day or later after administration of ITZ. Their associations with endogenous marker levels of hepatic function including plasma coproporphyrin (CP)-I and OATP1B1 genotypes were assessed. RESULTS: The serum level of total bilirubin (T-Bil) was moderately correlated with the plasma concentration of total ITZ (tITZ) and OH-ITZ (tOH-ITZ). T-Bil elevation above 0.3 mg/dL was observed in 19% of patients, although statistically significant difference was not identified. The plasma concentration of tITZ had no correlation with other endogenous markers levels including AST, ALT, albumin, and plasma CP-I. The serum AST and plasma CP-I levels were correlated with the plasma concentration of free OH-ITZ (fOH-ITZ). T-Bil and plasma CP-I, a marker of OATP1B1 activity, were not correlated with each other, and neither was associated with the OATP1B1 genotypes. CONCLUSIONS: Plasma ITZ and OH-ITZ had a positive association with T-Bil. The patients with a higher fOH-ITZ level had lower OATP1B1 activity on the basis of plasma CP-I level. ITZ and OH-ITZ have the potential to slightly increase endogenous marker levels of hepatic function, although most likely by different mechanisms.

Stereoselective interaction of tolvaptan with amiodarone under racemic metabolic impact by CYP3A5 genotypes in heart failure patients.

PURPOSE: The diuretic effect of tolvaptan is largely blood level-dependent although it does exhibit interindividual differences according to cytochrome P450 (CYP) 3A5 genotype. This study aimed to investigate the pharmacokinetic relationship between plasma tolvaptan and its monohydroxylate enantiomers and the factors affecting their metabolism in heart failure patients. METHODS: Japanese heart failure patients (n = 88) receiving oral tolvaptan (median dosage 7.5 mg/day) were enrolled. Blood samples were collected prior to the dosing on day 6 or later after first administration to determine the plasma concentrations of tolvaptan and its monohydroxylate enantiomers. Gene polymorphisms of CYP3A5, carbonyl reductase (CBR) 1/3, and ATP-binding cassette subfamily B member (ABCB) 1 were analyzed for their impact on tolvaptan pharmacokinetics. Serum laboratory test values and concomitant use of amiodarone were evaluated as factors related to tolvaptan metabolism. RESULTS: The median of the sum of the 5S- and 5R-tolvaptan plasma concentrations was 48.9 (range, 15.3-100) ng/mL. CYP3A5 genotypes significantly affected the concentration ratio of all enantiomeric metabolites to tolvaptan, while the other metabolic-related gene polymorphisms had no influence. A negative correlation was found between serum albumin and the enantiomeric ratio of tolvaptan and monohydroxylate DM-4111. Concomitant use of amiodarone increased the plasma levels of whole tolvaptan but significantly decreased the metabolic ratios of 5R-tolvaptan. 5S-tolvaptan was selectively synthesized from ketone MOP-21826 by CBR1 with a substantially smaller reaction velocity compared to tolvaptan monohydroxylation by CYP3A4/5. CONCLUSION: This study clarified the racemic impact of CYP3A5 genotypes on tolvaptan metabolism. Amiodarone may stereoselectively interact with R-forms rather than S-forms of tolvaptan.

Impacts of cachexia progression in addition to serum IgG and blood lymphocytes on serum nivolumab in advanced cancer patients.

PURPOSE: Serum nivolumab concentrations exhibit a large variation in cancer patients. Cancer cachexia inducing systemic inflammation promotes the elimination of endogenous proteins, while its association with serum nivolumab remains unclear. The present study aimed to evaluate the impacts of cachexia progression in addition to blood components on serum nivolumab in cancer patients. METHODS: Thirty-eight non-small-cell lung cancer or renal cell cancer patients receiving biweekly intravenous nivolumab were enrolled. Blood samples were collected just before dosing at the 7th administration of nivolumab or later. Serum nivolumab together with serum proteins, inflammatory markers, and peripheral blood leukocytes were determined. Cancer cachexia was classified using the Glasgow Prognostic Score (GPS). Immune-related adverse events (irAEs) were monitored during the study period. RESULTS: Cancer patients had a large variation in serum nivolumab concentrations (interquartile range, 12-21 µg/mL per mg/kg). The serum nivolumab concentration was positively correlated with serum albumin, while negatively associated with serum globulin and immunoglobulin G (IgG). A negative correlation was observed between serum nivolumab and blood lymphocytes. Regarding cachexia progression, the patients with GPS 2 had a higher serum interleukin-6 concentration and a lower serum nivolumab concentration than those with GPS 0 or 1. The GPS, serum IgG, and blood lymphocytes were identified as independent variables for serum nivolumab. The incidence of irAEs was not associated with the nivolumab dose or serum nivolumab. CONCLUSION: Cachexia progression had a negative impact on serum nivolumab in cancer patients. The interindividual variation in serum nivolumab was characterized by cachexia progression in addition to blood components.

Simple Liquid Chromatography-Tandem Mass Spectrometry Method for Quantitation of Total and Free Aprepitant and Its Active N-Dealkylated Metabolites in Human Plasma.

BACKGROUND: Aprepitant, an antiemetic selective neurokinin-1 receptor antagonist, is primarily metabolized to the active N-dealkylated form (ND-AP) and then converted to its carbonyl form (ND-CAP) in humans. This study developed a simple liquid chromatography-tandem mass spectrometry method using electrospray ionization for the quantitation of plasma total and free aprepitant and its N-dealkylated metabolites and used them to analyze patient plasma. METHODS: Free aprepitant and ND-AP in plasma were fractionated using centrifugal ultrafiltration. The analytes in plasma or their ultrafiltered specimens treated with triethylamine/acetonitrile were isocratically separated using a 3-µm octadecylsilyl column with a total run time of 10 minutes and scanned using positive ion electrospray ionization. RESULTS: The calibration curves of total aprepitant, ND-AP, and ND-CAP were prepared at concentration ranges of 50-2500, 20-1000, and 5-250 ng/mL, respectively, whereas that of free aprepitant and ND-AP were at a concentration range of 2-150 ng/mL. The intraassay and interassay accuracy and imprecision values were 93.5%-107.7% and 94.6%-103.3%, and 2.1%-7.5% and 1.0%-8.9%, respectively. Aprepitant and its metabolites did not exhibit any matrix effects or instabilities in the plasma specimens. In cancer patients receiving oral aprepitant, the plasma concentration ranges of total aprepitant, ND-AP, and ND-CAP, and free aprepitant and ND-AP were 137-2170, 104-928, 22.4-97.6, 8.11-60.0, and 3.53-56.0 ng/mL, respectively. The median plasma free fraction proportion of aprepitant and ND-AP was 4.14% and 4.90%, respectively. CONCLUSIONS: The present developed method showed an acceptable analytical performance and can be used to evaluate total and free aprepitant and its N-dealkylated metabolites in patient plasma.

Association Between the Prothrombin Time-International Normalized Ratio and Concomitant Use of Antibiotics in Warfarin Users: Focus on Type of Antibiotic and Susceptibility of Bacteroides fragilis to Antibiotics.

BACKGROUND: The difference in type of antibiotics and susceptibility of Bacteroides fragilis to antibiotics may influence warfarin anticoagulation. However, these influences have not been clarified in clinical settings. OBJECTIVES: This study aimed to investigate association the between the prothrombin time-international normalized ratio (PT-INR) and concomitant use of antibiotics in a real-world population of warfarin users. METHODS: This was a single-center cohort study using data from health records and included patients who received ß-lactams (BLs)/fluoroquinolones (FQs) during ongoing warfarin treatment (2011-2015) at Hamamatsu University Hospital in Japan. Antibiotics were categorized into those to which B fragilis is susceptible (BLsus, FQsus) and those to which it is not (BLnon, FQnon) and into those given orally (BLpo, FQpo) or intravenously (BLiv, FQiv). Outcomes were excessive PT-INR and changes in PT-INR, defined as the ratio (INR ratio) and difference (ΔINR) of maximum PT-INR and baseline PT-INR. Excessive PT-INR was graded as INR ratio of >1.5 or >2.5. RESULTS: A total of 1185 warfarin users were included. The proportion of INR ratio >2.5 in FQiv was higher than in BLiv (95% CI: 1.59-46.5). The proportions with an INR ratio of >1.5 in BLsus and FQsus were higher than in BLnon (1.72-14.1) and FQnon (1.05-9.36), respectively. ΔINR values in FQpo, FQiv, and FQsus were higher than those in BLpo, BLiv, and FQnon, respectively. CONCLUSIONS AND RELEVANCE: Concomitant use of FQs, or of antibiotics to which B fragilis is susceptible is associated with higher risk of excessive anticoagulation. These findings would contribute to safe and proper antibiotic treatment in warfarin users.

Associations between plasma hydroxylated metabolite of itraconazole and serum creatinine in patients with a hematopoietic or immune-related disorder.

PURPOSE: Serum markers of renal function have not been characterized in patients treated with itraconazole (ITZ). This study aimed to evaluate the associations between plasma ITZ and its hydroxylated metabolite (OH-ITZ) concentrations and serum markers of renal function in patients with hematopoietic or immune-related disorder. METHODS: This study enrolled 40 patients with hematopoietic or immune-related disorder who are receiving oral ITZ solution. Plasma concentrations of ITZ and OH-ITZ at 12 h after dosing were determined at steady state. Their relationships with serum levels of creatinine and cystatin C and their estimated glomerular filtration rate (eGFR) were evaluated. RESULTS: The free plasma concentration of ITZ had no correlation with serum creatinine and serum creatinine-based estimated glomerular filtration rate (eGFR-cre). The free plasma concentration of OH-ITZ was positively and negatively correlated with serum creatinine and eGFR-cre, respectively. The free plasma concentrations of ITZ and OH-ITZ had no association with serum cystatin C and serum cystatin C-based eGFR. Serum creatinine was higher by 16% after than before starting ITZ treatment, while eGFR-cre was lower by 9.3%. The serum creatinine ratio after/before ITZ treatment was positively correlated with the free plasma concentration of OH-ITZ. The patients co-treated with trimethoprim-sulfamethoxazole had higher serum creatinine. Concomitant glucocorticoid administration did not significantly alter serum cystatin C. CONCLUSIONS: Patients with hematopoietic or immune-related disorder treated with oral ITZ had a higher level of serum creatinine. Although serum creatinine potentially increases in conjunction with the free plasma concentration of OH-ITZ, concomitant ITZ administration has a slight impact on the eGFR-cre level in clinical settings.

A Reversed-Phase Mode LC-MS/MS Method Using a Polysaccharide Chiral Selector for Simultaneous Quantitation of Each Enantiomer of Tramadol and its Metabolites in Human Plasma and Evaluation of CYP-Mediated Stereoselective Demethylation.

BACKGROUND: The enantiomeric pharmacokinetics and metabolism of tramadol and its metabolites have not fully been understood. This study aimed to develop a reversed-phase mode liquid chromatography coupled to a tandem mass spectrometry method for the enantiomeric quantitation of tramadol and its metabolites in human plasma and to evaluate the stereoselective demethylation. METHODS: Racemic tramadol and its metabolites in plasma specimens were separated using a chiral selector coated with cellulose tris(3,5-dimethylphenylcarbamate) on silica gel under a reversed-phase mode. The mass spectrometer ran in the positive ion multiple-reaction monitoring mode. This method was performed to quantify plasma samples from 20 cancer patients treated with oral tramadol. The stereoselective demethylation was evaluated using recombinant cytochrome P450 (CYP) enzymes. RESULTS: The calibration curves of (+)- and (-)-tramadol, (+)- and (-)-O-desmethyltramadol (ODT), and (+)- and (-)-N-desmethyltramadol (NDT) were linear over the plasma concentration ranges of 6.25-800, 1.25-160, and 3.13-400 ng/mL for the respective enantiomers. In the present method, the intra- and inter-day accuracies and imprecisions were 94.2%-108.3% and 0.5%-6.0% for all analytes. The plasma concentrations of (+)-tramadol and NDT were higher than those of (-)-enantiomers. In contrast, no differences were observed between the plasma concentrations of (+)- and (-)-ODT. In the demethylation assay, the O-demethylations of tramadol and NDT by CYP2D6 were (-)-form-selective. CONCLUSIONS: The present method can be useful in the enantiomeric evaluation of tramadol and its metabolites in human plasma. Although CYP2D6 contributed to the stereoselective demethylation of tramadol, remarkable differences between (+)- and (-)-ODT were not observed in the plasma of the cancer patients.

Impact of Cachexia and Opioid Analgesic Cotreatment on Pregabalin Pharmacokinetics and Central Nervous System Symptoms in Cancer Patients.

BACKGROUND: Patients with cancer receiving pregabalin potentially have a high incidence of central nervous system (CNS) symptoms. The purpose of this study was to explore clinical factors influencing the incidence of CNS symptoms, including plasma pregabalin exposure, cancer cachexia, and opioid analgesic cotreatment. METHODS: Sixty-eight patients with cancer receiving twice-daily pregabalin were enrolled. Plasma concentrations of pregabalin, clinical laboratory data, opioid analgesic cotreatment, and the Glasgow Prognostic Score, which is an inflammation-based cachexia score, were considered as clinical factors. The incidence of CNS symptoms was collected from the patients' medical records. The predose plasma concentrations of pregabalin at steady state were determined by ultra-high-performance liquid chromatography. RESULTS: The steady-state trough plasma pregabalin concentrations showed a large variability with an interquartile range of 0.43-1.2 mg/L per mg/kg and were negatively correlated with an estimated glomerular filtration rate (eGFR). C-reactive protein (standardized partial regression coefficient, ß = 0.31) and opioid analgesic cotreatment (ß = 0.24) were also identified in addition to eGFR (ß = -0.60) in the multiple regression analysis. The incidence of CNS symptoms was significantly increased with opioid analgesic cotreatment and a higher Glasgow Prognostic Score but not with the absolute value of plasma pregabalin concentrations, eGFR, or other clinical laboratory data. CONCLUSIONS: In patients with cancer, steady-state trough plasma pregabalin concentrations were altered with renal function, systemic inflammation, and opioid analgesic cotreatment. However, a higher incidence of CNS symptoms observed in patients with cancer on pregabalin was more related to cachexia and opioid analgesic cotreatment than to altered pregabalin concentrations.

Optimization of Individual Pharmacotherapy Based on Multiple Evaluations of Patient Data.

To date, limited drug information is available for the individual optimization of pharmacotherapy. The author attempted multiple evaluations of patient data on factors related to the pharmacokinetics, drug efficacy, and adverse reactions observed in clinical settings. Through the clinical studies, drug information on the individual optimization of pharmacotherapy needed by health professionals including physicians and pharmacists was identified. Major findings were: 1) Cachectic cancer patients had high plasma concentrations of oxycodone via the reduction of CYP3A activity. The metabolic reduction in cachectic cancer patients was potentially related to the elevated serum level of interleukin-6. 2) Dopamine receptor D2 (DRD2) genetic mutations and being female led to poor antiemetic efficacy of the treatment of opioid-induced nausea in prochlorperazine-treated patients. The opioid receptor µ1 (OPRM1) wild genotype in addition to being female and having high plasma concentrations of prochlorperazine increased prolactin secretion during oxycodone treatment. 3) Rheumatoid arthritis patients with a genetic mutation of ATP-binding cassette subfamily B member 1 (ABCB1) had high plasma concentrations of tacrolimus and its 13-O-demethylate. The ABCB1 genetic mutation and associated high plasma concentration of tacrolimus decreased kidney function. 4) Chronic inflammation increased the plasma voriconazole concentration via its poor metabolism, whereas it did not alter the plasma itraconazole concentration. Although co-administration of prednisolone did not affect the plasma concentration of triazole antifungals, it weakly increased voriconazole metabolism. 5) In breastfeeding women, the median milk/plasma concentration ratio of amlodipine was 0.85. However, the observed relative infant dose of amlodipine in most patients was less than 10%.

Impact of Light Shielding on Photo-Degradation of Dacarbazine during the Preparation Process.

Dacarbazine (DTIC) is converted to the photo-degradation product 4-diazoimidazole-5-carboxamide (Diazo-IC) by light. Diazo-IC production is often responsible for the pain reactions observed during peripheral intravenous infusion of DTIC in clinical settings. Although light shielding during infusion decreases the photo-degradation of DTIC, its usefulness for the preparation of DTIC has not yet been fully clarified. The aim of this study was to investigate the light conditions during the preparation of DTIC solution in the compounding room from the viewpoint of the production amount of Diazo-IC. DTIC solution was prepared in the compounding room. Various light and temperature conditions and dissolving solutions during the preparation were investigated. The amounts of DTIC and Diazo-IC in solutions were determined using an HPLC coupled to UV detection. The photo-degradation of DTIC was estimated by the amount of Diazo-IC. Diazo-IC production in the dissolving solutions increased in a time-dependent manner at 4 and 25°C under light shielding. Light exposure during the dissolving process did not affect the DTIC and Diazo-IC concentrations. Light shielding during dissolution did not alter the Diazo-IC production until 4 h after dilution. In conclusion, short duration light exposure did not affect Diazo-IC production. These findings suggest that light shielding is not needed in the preparation of DTIC in the compounding room from the viewpoint of Diazo-IC production.

Impact of flavin-containing monooxygenase 3 and CYP2C19 genotypes on plasma disposition and adverse effects of voriconazole administered orally in immunocompromised patients.

Flavin-containing monooxygenase (FMO) 3 together with cytochrome P450 (CYP) 2C19 play a significant role in voriconazole N-oxidation. This study aimed to evaluate the influence of FMO3 and CYP2C19 genotypes on the plasma disposition and adverse effects of voriconazole in immunocompromised patients. Sixty-five Japanese immunocompromised patients receiving oral voriconazole were enrolled. Predose plasma concentrations of voriconazole and N-oxide were determined at day 5 or later. The adverse effects of voriconazole and the FMO3 and CYP2C19 genotypes were investigated. The patients with FMO3 E158K/E308G had a lower plasma concentration of voriconazole. The metabolic ratio to N-oxide was significantly higher in the FMO3 E158K/E308G group than in the wild group. In contrast, FMO3 V257M was not associated with the plasma concentration of voriconazole. No significant difference was observed in the saturation index, defined as a correlation coefficient of the regression line between the absolute plasma concentration of voriconazole and the inverse value of the metabolic ratio to N-oxide, between the FMO3 genotypes. CYP2C19 phenotype did not affect the plasma concentration and metabolic ratio of voriconazole. The saturation index of voriconazole rose in the order of CYP2C19 extensive, intermediate, and then poor metabolizer groups. However, the FMO3 and CYP2C19 genotypes and their associated voriconazole pharmacokinetics did not have an effect on the incidence of adverse effects. In conclusion, FMO3 E158K/E308G decreased the plasma concentration of voriconazole through its higher metabolic activity. The FMO3 genotype altered the plasma exposure of voriconazole, while the CYP2C19 phenotype affected the metabolic capacity in immunocompromised patients.

Simple LC-MS/MS Methods Using Core-Shell Octadecylsilyl Microparticulate for the Quantitation of Total and Free Daptomycin in Human Plasma.

BACKGROUND: Daptomycin, a cyclic lipopeptide antibiotic, displays high plasma protein binding. This study developed the simple method of liquid chromatographic separation using a core-shell octadecylsilyl microparticulate coupled to tandem mass spectrometry for the quantitation of total and free daptomycin in human plasma. METHODS: Free daptomycin in plasma was obtained by centrifugal ultrafiltration. Deproteinized plasma specimens were directly separated using a core-shell octadecylsilyl microparticulate with isocratic elution. The mass spectrometer was run in positive-ion electrospray ionization mode. This method was applied to the quantitation of plasma samples in patients treated with intravenous daptomycin. RESULTS: Daptomycin and diazepam as an internal standard were eluted with a total run time of 10 minutes. The calibration curves of total and free daptomycin in human plasma were linear over the concentration ranges of 1-100 and 0.1-10 mcg/mL, respectively. The lower limits of quantitation of the total and free daptomycin in human plasma were 1.0 and 0.1 mcg/mL, respectively. Their extraction recovery rates in nonfiltrated and ultrafiltrated plasma samples were 106.1% and 98.2%, respectively. Total and free daptomycin did not exhibit any matrix effects in human plasma. The intraday and interday accuracies and imprecisions of total daptomycin were 88.7%-106.0% and 98.7%-105.9%, and within 4.1% and 10.4%, whereas those of free daptomycin were 86.8%-101.6% and 103.0%-107.8%, and within 14.6% and 14.6%, respectively. The plasma concentration ranges of total and free daptomycin in 15 infected patients were 3.01-34.1 and 0.39-3.64 mcg/mL, respectively. The plasma protein binding rate of daptomycin ranged from 80.8% to 94.9%. CONCLUSIONS: The present simple method with an acceptable analytical performance can be helpful for monitoring the pharmacokinetics of daptomycin in infected patients observed in clinical settings.

Impact of CYP genotype and inflammatory markers on the plasma concentrations of tramadol and its demethylated metabolites and drug tolerability in cancer patients.

PURPOSE: Clinical responses to oral tramadol show a large variation in cancer patients. This study aimed to evaluate the impacts of cytochrome P450 (CYP) genotype and serum inflammatory markers on the plasma concentrations of tramadol and its demethylated metabolites and drug tolerability in cancer patients. METHODS: The predose plasma concentrations of tramadol and its demethylated metabolites were determined at day 4 or later in 70 Japanese cancer patients treated with oral tramadol. The CYP genotypes, serum interleukin-6 (IL-6) and C-reactive protein (CRP) levels, and the duration of tramadol treatment were evaluated. RESULTS: The CYP2D6 genotype did not affect the plasma tramadol concentration. The plasma concentration of O-desmethyltramadol and its ratio to tramadol were lower in the CYP2D6 intermediate and poor metabolizer (IM + PM) group than in the normal metabolizer (NM) group (P = 0.002 and P = 0.023). The plasma concentration of N-desmethyltramadol and its ratio to tramadol were higher in the CYP2D6 IM + PM group than in the NM group (P = 0.001 and P = 0.001). The CYP2B6*6 and CYP3A5*3 alleles had no effect on the plasma concentrations of tramadol and its demethylated metabolites. The serum IL-6 and CRP levels were inversely correlated with the plasma concentration ratios of N-desmethyltramadol to tramadol and of N,O-didesmethyltramadol to O-desmethyltramadol. The serum IL-6 level was associated with the treatment duration of oral tramadol. CONCLUSIONS: The CYP2D6 genotype but not the CYP2B6 and CYP3A5 genotypes affected the plasma concentrations of O- and N-desmethyltramadol through alteration of the tramadol metabolic pathway. The serum IL-6 level was associated with N-demethylation activity and tramadol tolerability.

Validated LC-MS/MS Method for the Simultaneous Determination of Amlodipine and Its Major Metabolites in Human Plasma of Hypertensive Patients.

BACKGROUND: No information on the pharmacokinetic characteristics of amlodipine (AML) metabolites is available. This study aimed to develop a method based on isocratic liquid chromatography coupled to tandem mass spectrometry for the simultaneous determination of AML and its 2 major metabolites, dehydroamlodipine (DH-AML) and O-des[2-aminoethyl]-O-carboxymethyl DH-AML (CM-DH-AML), and to use it for monitoring this drug in hypertensive patients. METHODS: Acetonitrile-deproteinized plasma specimens were separated using an octadecyl-silica column (3-µm particle size) with a mobile phase consisting of 50% methanol containing 0.15% of formic acid in water. The run time was 9 minutes. The mass spectrometer was run in the positive ion electrospray ionization mode. This method was applied for the determination of AML and its metabolites in plasma samples from patients treated with this drug. RESULTS: The calibration curves in human plasma of AML, DH-AML, and CM-DH-AML were linear over the concentration ranges of 0.5-64, 1-64, and 0.5-64 ng/mL, respectively, and their lower limits of quantification were 0.5, 1, and 0.5 ng/mL, respectively. Their extraction recovery rates and matrix factors in human plasma were 94.8%-109.0% and 97.0%-101.4%, respectively. The intra-assay and interassay imprecisions and accuracies were within 10.8% and 95.4%-111.2%, respectively. The plasma concentration ranges of AML, DH-AML, and CM-DH-AML were 6.5-20.9, 1.4-10.9, and 5.6-38.3 ng/mL, respectively. CONCLUSIONS: The present method with acceptable analytical performance can be helpful for monitoring the plasma concentration of AML, including the determination of its metabolites in patients with hypertension.

Transfer of vaginal chloramphenicol to circulating blood in pregnant women and its relationship with their maternal background and neonatal health.

Few clinical studies have determined the quantitative transfer of vaginal chloramphenicol to circulating blood in pregnant women. This study aimed to evaluate the plasma concentration of chloramphenicol in pregnant women treated with trans-vaginal tablets and its relationship with maternal background and neonatal health. Thirty-seven pregnant women treated with 100 mg of trans-vaginal chloramphenicol once daily for bacterial vaginosis and its suspected case were enrolled. The plasma concentration of chloramphenicol was determined using liquid chromatography coupled to tandem mass spectrometry at day 2 or later after starting the medication. The correlations between the maternal plasma concentration of chloramphenicol and the background and neonatal health at birth were investigated. Chloramphenicol was detected from all maternal plasma specimens and its concentration ranged from 0.043 to 73.1 ng/mL. The plasma concentration of chloramphenicol declined significantly with the administration period. The plasma concentration of chloramphenicol was lower at the second than the first blood sampling. No correlations were observed between the maternal plasma concentration of chloramphenicol and background such as number of previous births, gestational age at dosing, and clinical laboratory data. Neonatal infant health parameters such as birth-weight, Apgar score at birth, and gestational age at the time of childbearing were not related to the maternal plasma concentration of chloramphenicol. Vaginal chloramphenicol transfers to circulating blood in pregnant women. The maternal plasma concentration of chloramphenicol varied markedly and was associated with the administration day, but not with maternal background or her neonatal health.