Faculty Profiles - AIBA Tetsuya

Papers - AIBA Tetsuya

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Population Pharmacokinetic Analysis of Vancomycin Using Serum Cystatin C as a Marker of Renal Function Reviewed

Akihiro Tanaka, Tetsuya Aiba, Takashi Otsuka, Katsuya Suemaru, Tatsuya Nishimiya, Tomoyoshi Inoue, Mitsuharu Murase, Yuji Kurosaki, Hiroaki Araki

Antimicrobial Agents and Chemotherapy 54 ( 2 ) 778 - 782 2010.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC MICROBIOLOGY

We determined the population pharmacokinetics of vancomycin (VAN) using the glomerular filtration rate (GFR) estimated from the serum cystatin C concentration. We examined the predictive performance of the trough serum VAN concentration for determination of the initial dose by using a new model for the analysis of the population pharmacokinetic parameters. Data for 86 patients were used to estimate the values of the population pharmacokinetic parameters. Analysis with a nonlinear mixed-effects modeling program was done by using a one-compartment model. Data for 78 patients were used to evaluate the predictive performance of the new model for the analysis of population pharmacokinetic parameters. The estimated GFR values determined by using Hoek's formula correlated linearly with VAN clearance (VAN clearance [ml/min] = 0.825 x GFR). The mean volume of distribution was 0.864 (liters/kg). The interindividual variability of VAN clearance was 19.8%. The accuracy of the prediction determined by use of the new model was statistically better than that determined by use of the Japanese nomogram-based model because the 95% confidence interval (-3.45 to -1.38) of the difference in each value of the mean absolute error (-2.41) did not include 0. Use of the serum cystatin C concentration as a marker of renal function for prediction of serum VAN concentrations may be useful.

DOI： 10.1128/AAC.00661-09

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乳児を対象としたバルプロ酸血中遊離型濃度の母集団解析

上島智, 合葉哲也, 佐藤智昭, 松永尚, 黒崎勇二, 大塚頌子, 千堂年昭

臨床薬理 40 ( Suppl. ) S242 - S242 2009.11

ヨード造影剤と相互作用を有する薬剤に対するリスクマネジメント

清水けい子, 勝部理早, 岡崎宏美, 千堂年昭, 合葉哲也, 黒崎勇二

日本医療薬学会年会講演要旨集 19 304 - 304 2009.9

Poor applicability of estimation method for adults to calculate unbound serum concentrations of valproic acid in epileptic neonates and infants Reviewed

S. Ueshima, T. Aiba, N. Ishikawa, T. Sato, H. Kawasaki, Y. Kurosaki, Y. Ohtsuka, T. Sendo

Journal of Clinical Pharmacy and Therapeutics 34 ( 4 ) 415 - 422 2009.8

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL PUBLISHING, INC

Objective:
To characterize the relationship between total and unbound concentrations of valproic acid (VPA) in epileptic neonates and infants, the clinical examination records of those patients archived via therapeutic drug monitoring (TDM) activities were retrospectively analyzed.
Methods:
The screening encompassed 249 records of 114 epileptic patients aged 0-19 years old, who were treated with VPA monotherapy and whose total and unbound VPA concentrations were determined. These data were divided into groups according to the patients' age. In each group, the relationship between total and unbound VPA concentrations was compared to a reference profile, and the deviation from the reference was evaluated. The reference profile was calculated using the Langmuir equation, in which two parameters Kd and Bm were set to 7 center dot 8 and 130 mu g/mL, respectively, according to our previous findings.
Results:
The relationship between total and unbound VPA concentrations of patients of 0 years old considerably deviated from the reference, and their unbound VPA concentrations were generally higher compared to the corresponding reference values. It is suggested that the large deviation is related to the fact that the serum albumin concentrations of patients younger than 1 year old tend to be lower than those of patients in other age groups.
Conclusion:
Since the relationship between the VPA concentrations of epileptic neonates and infants is noticeably different from the reference, the unbound serum VPA concentrations of these patients are not adequately estimated using the same method as that for grown-ups. The unbound VPA concentrations of neonates and infants should be explicitly determined via TDM activities.

DOI： 10.1111/j.1365-2710.2009.01022.x

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乳児を対象としたバルプロ酸血中遊離型濃度の高精度推定式の構築

上島智, 合葉哲也, 佐藤智昭, 川崎博己, 黒崎勇二, 大塚頌子, 松永尚, 千堂年昭

TDM研究 26 ( 3 ) s161 - s161 2009.6

新規レチノイドX受容体アゴニストNEt-3IPのラットにおける体内動態評価

小笠原明美, 薬師寺信匡, 合葉哲也, 川崎博己, 黒崎勇二, 加来田博貴

日本薬学会年会要旨集 129年会 ( 4 ) 220 - 220 2009.3

Efficacy of Peritoneal Dialysis of Tolbutamide in Rats Under Conditions of the Plasma Unbound Fraction Being Increased Reviewed

Takashi Makita, Tetsuya Aiba, Yuki Izuwa, Yukiko Komori, Hiromu Kawasaki, Yuji Kurosaki

Biopharmacutics and Drug Disposition 30 ( 1 ) 1 - 8 2009.1

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：JOHN WILEY & SONS LTD

Peritoneal dialysis of a highly protein-bound compound, tolbutamide, was examined in rats to clarify whether the efficacy of the peritoneal dialysis of such compounds increases proportionally as their unbound fractions increase. As expected, it was shown that the tolbutamide concentration of the peritoneal dialysate rose as the unbound fraction of tolbutamide increased. However, the efficacy of peritoneal dialysis of tolbutamide was proportionally elevated only when the unbound fraction was slightly increased by sulfa methoxazol e treatment. When the unbound fraction of tolbutamide was increased 7.8 times by sulfa dimethoxin e treatment, the dialysis efficacy was increased to only 58% of that expected. This discrepancy between the observed and expected values regarding dialysis efficacy was more marked when experiments were performed in rats with experimentally induced acute renal failure. Pharmacokinetic analysis indicated that the intrinsic dialysis clearance of tolbutamide decreased when its unbound fraction was greatly increased. These findings suggest that peritoneal dialysis may be mediated not only by passive diffusion, but also by concentration-dependent processes. The efficacy of the peritoneal dialysis of therapeutic compounds may be overestimated if the estimation is based only on their unbound fraction measured under control conditions. Copyright (C) 2009 John Wiley & Sons, Ltd.

DOI： 10.1002/bdd.640

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Comparative Study of Increased Plasma Quinidine Concentration in Rats with Glycerol- and Cisplatin-induced Acute Renal Failure Reviewed

Yuki Izuwa, Jun-ichi Kusaba, Mizuki Horiuchi, Tetsuya Aiba, Hiromu Kawasaki, Yuji Kurosaki

Drug Metabolism and Pharmacokinetics 24 ( 5 ) 451 - 457 2009

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：JAP SOC STUDY XENOBIOTICS

A comparative study of altered plasma concentration of quinidine in rats with glycerol- and cisplatin-induced acute renal failure (ARF) was conducted with quinidine used as a positively charged and liver-metabolized therapeutic compound. Although apparent total body clearance of quinidine decreased to 68 and 48% of the normal value in glycerol- and cisplatin-induced ARF rats, respectively, its distribution decreased only in glycerol-induced ARF rats. The plasma unbound fraction of quinidine decreased in glycerol-induced ARF rats, which was not observed in cisplatin-induced ARF rats. The plasma level of alpha(1)-acid glycoprotein (AGP) increased in glycerol-induced ARF, but not in cisplatin-induced ARF rats. It is therefore conceivable that the plasma concentration of positively charged and liver-metabolized compounds generally increases due to hepatic elimination suppressed as renal function decreases, but the pharmacokinetic impact of suppressed hepatic elimination is occasionally difficult to observe in some ARF model rats since it may be blurred by the influence of increased plasma AGP level.

DOI： 10.2133/dmpk.24.451

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Decreased lithium disposition to cerebrospinal fluid in rats with glycerol-induced acute renal failure Reviewed

Rie Sakae, Atsuko Ishikawa, Tomoko Niso, Yukiko Komori, Tetsuya Aiba, Hiromu Kawasaki, Yuji Kurosaki

Pharmaceutical Research 25 ( 10 ) 2243 - 2249 2008.10

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER/PLENUM PUBLISHERS

Purpose. The lithium disposition to cerebrospinal fluid (CSF) was evaluated in rats with acute renal failure (ARF) to examine whether electrolyte homeostasis of the CSF is perturbed by kidney dysfunction. In addition, the effects of renal failure on choroid plexial expressions of the Na+-K+-2Cl(-) co-transporter (NKCC1) and Na+/H+ exchanger (NHE1) were also studied.
Methods. After lithium was intravenously administered at a dose of 4 mmol/kg, its concentration profile in plasma was evaluated by collecting plasma specimens, while that in CSF was monitored with a microdialysis probe in the lateral ventricles. NKCC1 and NHE1 expressions were measured via the Western immunoblot method using membrane specimens prepared from the choroid plexus in normal and ARF rats.
Results. The lithium concentration in CSF of ARF rats was 30% lower than that of normal rats, while their plasma lithium profiles were almost the same, indicating that the lithium disposition to CSF was decreased in ARF rats. It was revealed that the choroid plexial expression of NKCC1 was increased by 40% in ARF rats, but that of NHE1 was unchanged.
Conclusion. ARF decreases the lithium disposition to CSF, possibly by promoting lithium efflux from CSF due to increased NKCC1 expression in the choroid plexus.

DOI： 10.1007/s11095-008-9612-5

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Frequency of decreased renal function between patients treated with brand and generic products of vancomycin hydrochloride injection Reviewed

Yuki Izuwa, Satoshi Ueshima, Tomoaki Sato, Masatoshi Okazaki, Tetsuya Aiba, Hiromu Kawasaki, Yuji Kurosaki, Toshiaki Sendo

YAKUGAKU ZASSHI-JOURNAL OF THE PHARMACEUTICAL SOCIETY OF JAPAN 128 ( 10 ) 1493 - 1498 2008.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：PHARMACEUTICAL SOC JAPAN

The frequency of decreased renal function was compared between patients treated with brand and generic products of vancomycin injection (VCM) in a retrospective manner based on the clinical examination records archived in Okayama University Hospital. A total of 122 patients were found to have been solely treated with vancomycin injection for MRSA infection, and their examination records were analyzed. The renal function of those patients was evaluated based on the serum creatinine concentration (SCr), and patients whose SCr was maximally elevated above the defined upper limit of the normal range (1.20 mg/dl for mates and 0.96 mg/dl for females) were considered to show decreased renal function. Although the amount of VCM administered to patients was larger in the case of generic rather than brand products, the percentage of patients whose renal function was decreased during VCM treatment was not significantly different between the VCM products, in which 2 among 62 patients receiving the brand product and 4 among 60 receiving the generic product were reported to show decreased renal function. It was additionally revealed that 3 of those 4 patients with a decreased renal function related to the generic product were not treated as instructed by the package insert, and their trough VCM concentration exceeded the recommended level of 10 mu g/ml. With these findings, the brand and generic VCM products are considered to be similar regarding the adverse effect of decreasing renal function.

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岡山大学薬学部におけるPBL導入の現状と6年制に向けての課題

岡崎宏美, 四宮一昭, 名倉弘哲, 北村佳久, 合葉哲也, 高山房子, 黒崎勇二, 川崎博己, 千堂年昭

医療薬学フォーラム講演要旨集 16th 304 2008.7

ロバスト回帰を用いる難治性ネフローゼ患者におけるシクロスポリンのAUC推定方法に関する検討

上島智, 合葉哲也, 佐藤智昭, 黒崎勇二, 瀧上慶一, 杉山斉, 槇野博史, 千堂年昭

TDM研究 25 ( 3 ) s182 - s182 2008.6

塩酸バンコマイシンの先発医薬品と後発医薬品における腎障害発現状況の比較検討

出羽祐基, 上島智, 佐藤智昭, 岡崎昌利, 合葉哲也, 川崎博己, 黒崎勇二, 千堂年昭

日本薬学会年会要旨集 128年会 ( 4 ) 168 - 168 2008.3

Characterization of non-linear relationship between total and unbound serum concentrations of valproic acid in epileptic children Reviewed

S. Ueshima, T. Aiba, T. Makita, S. Nishihara, Y. Kitamura, Y. Kurosaki, H. Kawasaki, T. Sendo, Y. Ohtsuka, Y. Gomita

Journal of Clinical Pharmacy and Therapeutics 33 ( 1 ) 31 - 38 2008.2

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：BLACKWELL PUBLISHING

Objective: To establish a regression equation to properly estimate the unbound serum concentration of valproic acid (VPA) from its total serum concentration; the relationship between total and unbound serum VPA concentrations was retrospectively characterized.
Methods: Data were obtained from the clinical examination records that were routinely archived during therapeutic drug monitoring. The screening encompassed 342 records of 108 paediatric patients whose total and unbound VPA concentrations had been determined. The relationship between total and unbound VPA concentrations was characterized according to the Langmuir equation by taking account of inter-individual variability with the NONMEM program.
Results: The total VPA concentration (C-t) in the screened patients ranged from 5.5 to 179.8 mu g/mL, and the unbound VPA concentration (C-f) increased in a non-linear manner as the total VPA concentration increased. Taking account of the effects of antiepileptics concurrently administered, the VPA dissociation constant (K-d) and maximum binding site concentration (B-m) were 7.8 +/- 0.7 and 130 +/- 4.5 mu g/mL respectively, for the regression equation, C-t = C-f + B-m.C-f/(K-d + C-f). An alteration in the unbound concentration was seen in patients who were treated with the combination of VPA and ethosuximide and in those who received two additional antiepileptics.
Conclusions: A regression equation for estimation of the unbound VPA concentration, based on total VPA concentration collected during routine therapeutic drug monitoring was established. Use of two additional antiepileptics and ethosuximide treatment was considered as potential factors affecting unbound VPA concentration.

DOI： 10.1111/j.1365-2710.2008.00885.x

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Individualized dosage adjustment of valproic acid based on unbound serum concentration in intractable epileptic children Reviewed

Ueshima Satoshi, Aiba Tetsuya, Sato Tomoaki, Kawasaki Hiromu, Kurosaki Yuji, Ohtsuka Yoko, Sendo Toshiaki

YAKUGAKU ZASSHI-JOURNAL OF THE PHARMACEUTICAL SOCIETY OF JAPAN 128 92 2008

Application of the correlation of in vitro dissolution behavior and in vivo plasma concentration profile (IVIVC) for soft-gel capsules - a pointless pursuit? Reviewed

Hidekatsu Nishimura, Chlaki Hayashi, Tetsuya Aiba, Ichiro Okamoto, Yuji Miyamoto, Susumu Nakade, Kazuhisa Takeda, Yuji Kurosaki

Biological and Pharmaceutical Bulletin 30 ( 11 ) 2221 - 2225 2007.11

Language：English Publishing type：Research paper (scientific journal) Publisher：PHARMACEUTICAL SOC JAPAN

Plasma concentration profiles of arundic acid ((R)-(-)-2-propyloctanoic acid), an oil-like medicine, administered as soft-gel capsules in human clinical tests were predicted from the dissolution test data of the soft-gel capsules with different storage terms (short- and long-term stored drugs) by applying the in vitro-in vivo correlation (IVIVC). We established two linear-regression IVIVCs, which were characterized by either the in vitro dissolution behaviors against the pH 8.0 dissolution medium or the pH 6.8 dissolution medium containing 2% sodium dodecyl sulfate (SDS), in this study. Also, the prediction accuracies for the in vivo plasma profiles in humans for these two IVIVCs were compared. Regarding dissolution from the long-term stored capsule in pH 8.0 dissolution medium without surfactant, the prediction accuracies of the in vivo plasma profiles in humans were not satisfactory for the obtained IVIVC. The use of pH 6.8 dissolution medium containing 2% SDS, according to the Japanese guideline, improved the dissolution of the long-term stored capsule. Furthermore, the prediction accuracies for the in vivo plasma profiles in humans for these two IVIVCs were compared. The IVIVC established by the in vitro dissolution data obtained with the dissolution medium containing surfactant more effectively predicted the plasma drug concentration profiles following oral administrations of the soft-gel capsules under both storage conditions.

DOI： 10.1248/bpb.30.2221

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乳幼児における血中遊離形バルプロ酸濃度の遡及的解析

合葉哲也, 上島智, 石川七瀬, 佐藤智昭, 川崎博己, 黒崎勇二, 大塚頌子, 千堂年昭

臨床薬理 38 ( Suppl. ) S237 - S237 2007.11

Evaluation of intramuscular lateral distribution profile of topically administered acetaminophen in rats Reviewed

Yuji Kurosaki, Masahiro Tagawa, Akiho Omoto, Hiroshi Suito, Yukiko Komori, Hiromu Kawasaki, Tetsuya Aiba

International Journal of Pharmacetics 343 ( 1-2 ) 190 - 195 2007.10

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

To clarify to what extent topically administered drug molecules horizontally permeate into tissues surrounding the administration site, the intramuscular lateral concentration profile of acetaminophen was investigated in vivo using the microdialysis method in rats. When acetaminophen was intramuscularly administered for 6 h in a pinpoint manner at a constant rate of 3 mu g/min, it was clearly detected in the muscle surrounding the administration site, being 17.5 mu g/ml when measured at a 2 mm distance from the administration site. The concentration in the muscle was decreased as the distance increased, and those measured at 5 mm and 40 rum were 0.35 mu g/ml and 0.09 mu g/ml, respectively. In addition, it was shown that the concentration in the muscle at 40 turn reflected the compound's concentration in plasma, but not the compound's horizontal permeation from the administration site. With these observations, the intramuscular distribution profile of acetaminophen was numerically characterized according to Fick's law. As a result, it was revealed that horizontal permeation is the primary process accountable for the increased intramuscular concentration only in the area adjacent to the administration site, and the radius of the adjacent area was calculated to be 5.80 turn for acetaminophen. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ijpharm.2007.05.020

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てんかん患児における遊離形バルプロ酸濃度に及ぼす併用薬の影響

上島智, 合葉哲也, 佐藤智昭, 川崎博己, 黒崎勇二, 千堂年昭

TDM研究 24 ( 3 ) s153 - s153 2007.7

Alteration of therapeutic efficacy of lipid microspheres incorporating prostaglandin E-1 by mixing with aqueous solution Reviewed

Yukiko Komori, Tetsuya Aiba, Miki Kushima, Hiromu Kawasaki, Yuji Kurosaki

Journal of Pharmaceutical Sciences 96 ( 4 ) 935 - 943 2007.4

Language：English Publishing type：Research paper (scientific journal) Publisher：JOHN WILEY & SONS INC

To clarify whether the therapeutic efficacy of lipid microspheres incorporating prostaglandin E-1 (lipo-PGE(1)) is altered when mixed and coinfused with clinical solutions, the original lipo-PGE(1) solution (20 mu g/mL) was mixed with three clinical infusion solutions: 0.9% sodium chloride solution, Hartmann's solution, and fat emulsion for parenteral nutrition. These diluted lipo-PGE(1) (2 mu g/mL) solutions were administered to rats, and their hemodynamic and antiplatelet effects were examined. Peripheral blood flow was increased by 76 +/- 4% from the control level when the lipo-PGE(1) solution diluted with the fat emulsion was administered, while it was increased by 43 +/- 6% and 36 +/- 17%, respectively, when the lipo-PGE(1) solutions diluted with 0.9% sodium chloride and Hartmann's solution were administered. As for the antiplatelet effects of the lipo-PGE(1) solutions, the progression of digit gangrene in thromboangiitis obliterans (TAO) rats was significantly suppressed by the administration of lipo-PGE(1) solution diluted with the fat emulsion, but it was not suppressed by lipo-PGE(1) solution diluted with 0.9% sodium chloride. These findings indicate that the therapeutic efficacy of lipo-PGE(1) is decreased when it is mixed with an aqueous solution such as 0.9% sodium chloride.

DOI： 10.1002/jps.20790

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