Nobuyuki Wakui

Determination of tris(2-ethylhexyl)trimellitate released from PVC tube by LC-MS/MS.

Tris(2-ethylhexyl)trimellitate (TOTM) is used as an alternative plasticizer of polyvinyl chloride (PVC) medical devices. A method for the determination of TOTM released from PVC medical devices into intravenous preparations was developed, which uses liquid chromatography-tandem mass spectrometry (LC-MS/MS). A PVC tube was filled with an intravenous preparation and extraction was carried out by shaking for 1h at room temperature. LC was performed with an Inertsil-C8 (50 mm x 2.1 mm, 5 microm) column. The isocratic mobile phase was acetonitrile:purified water (90:10, v/v) at a flow rate of 0.2 ml/min. MS detection was accomplished with an MS/MS detector equipped with a turbo ionspray ionization source in the positive ion mode. The limit of detection and the limit of quantification for the standard solution of TOTM was 0.5 ng/ml (S/N=3) and 1.0 ng/ml (S/N > or =10), respectively. When Prograf (tacrolimus) was used, the average recovery of TOTM was 101.1% (R.S.D.=4.72%; n=3). When our method was applied to the determination of TOTM released from unsterilized and gamma-ray-sterilized PVC tubes, we found that a higher concentration of TOTM was released from the unsterilized PVC tube than from the gamma-ray-sterilized one.

Effect of gamma-ray irradiation on degradation of di(2-ethylhexyl)phthalate in polyvinyl chloride sheet

The risk assessment of di(2-ethylhexyl)phthalate (DEHP) migration from polyvinyl chloride (PVC) medical devices is an important issue for patients. The aim of this study was to determine DEHP degradation and migration from PVC sheets. To this end, the method for the simultaneous determination of DEHP and its breakdown products (mono(2-ethylhexyl)phthalate (MEHP) and phthalic acid (PA)) was improved. Their migration levels from 0 to 50 kGy gamma-ray irradiated PVC sheets were determined. DEHP migration level decreased in proportion to the dose of gamma-ray irradiation, while MEHP and PA migration levels increased. The hardness and the elastic modulus of PVC sheets were examined, but no clear relationship between DEHP migration and these parameters was observed.

Expression of hepatic cytochrome P450 in a mouse model of ulcerative colitis changes with pathological conditions

The expression levels of cytochrome P450 (CYP) in the liver were analyzed over time in dextran sulfate sodium (DSS)‐induced ulcerative colitis mouse model, from the initial active stage to the remission stage, to investigate the relationship between the changes in pathological conditions and CYP expression levels.

Determination of exposure of dispensary drug preparers to cyclophosphamide by passive sampling and liquid chromatography with tandem mass spectrometry

Objectives: To determine cyclophosphamide exposure to preparers during tablet crushing and subsequent handling by analyzing indoor air collected using a high-performance volatile organic compounds-solvent desorption (VOC-SD) passive air sampler. Methods: The passive sampler was taped to the mask over the mouth of the preparer and indoor air was collected during crushing and preparation of cyclophosphamide tablets (Endoxan®). After collection, the carbon molecular sieve adsorbent of the passive sampler was placed in a centrifuge tube, and 1 mL of carbon disulfide was used to elute cyclophosphamide from the adsorbent. Liquid–liquid extraction with 1 mL of water was performed, and the aqueous phase was used as the test solution. Cyclophosphamide concentration was determined by liquid chromatography with ultraviolet and tandem mass spectrometry detection. Results: Cyclophosphamide concentration was detected in the range of 7.6–157.7 ng/sampler. Our results showed that low-level exposure occurred near the mouth of the preparer, which could present risks for long-term exposure, especially if combined with multiple toxic drug exposures. Conclusion: The anticancer drug monitoring methodology described here is a simple exposure assessment that can be used to ensure the safety of hospital pharmacy tablet preparers. Furthermore, since the anticancer drug exposure risk is very high for preparers, preparation should be in hood or with face mask.

Menthol reduces the anticoagulant effect of warfarin by inducing cytochrome P450 2C expression.

Recently, it was reported that the anticoagulant effect of warfarin was reduced when patients receiving warfarin also took menthol. The purpose of this study is to reveal the mechanism of this reduced anticoagulant effect of warfarin from the pharmacokinetic point of view. Warfarin was orally administered to mice 24h after the administration of menthol for 2 days, and the plasma warfarin concentration was measured. In the menthol administration group, the area under the blood concentration time curve of warfarin was decreased by approximately 25%, while total clearance was increased to 1.3-fold compared to the control group. The hepatic cytochrome P450 (CYP) 2C protein expression level in the menthol administration group was significantly increased compared to that in the control group. An increase in the nuclear translocation of constitutive androstane receptor (CAR) was also observed. The addition of menthol to human hepatic cells, HepaRG cells, caused an increase in the mRNA expression level of CYP2C9. The results of this study revealed that menthol causes an increase in CYP2C expression levels in the liver, which leads to an enhancement of warfarin metabolism, resulting in a decreased anticoagulant effect of warfarin. It was also suggested that menthol acted directly on the liver and increased the expression level of CYP2C by enhancing the nuclear translocation of CAR.

Development of a closed drug preparation method for oral anticancer drugs

The objective of this article is to reduce the preparation time for oral anticancer drugs, reduce the exposure to drug preparations, and develop drug preparation equipment without external drug leaks in a closed state. In the newly developed closed oral drug preparation device, a 10 mL disposable syringe that was replaced with one projection for crushing tablets and a no-processing 30 mL disposable syringe were connected to a three-way stopcock. Using this instrument, Endoxan® tablets (principal components: cyclophosphamide) were crushed and suspended in water in a closed state. The drug was prepared to suspension and flowed out via a feeding tube by switching the handle of the three-way stopcock. To assess human exposure to cyclophosphamide, a high-performance volatile organic compound-solvent desorption passive sampler was attached to the preparer’s mouth to collect air drifting in the vicinity, and cyclophosphamide levels were subsequently measured by liquid chromatography with tandem mass spectrometry. Using the developed drug preparation equipment, Endoxan® tablets were suspended in a closed state. According to liquid chromatography with tandem mass spectrometry analysis, the exposure of the preparer to cyclophosphamide was greatly reduced when using the developed device; cyclophosphamide was detected in only two of the five samples, though only at trace levels. The closed oral drug preparation device may permit the preparation and administration of toxic drugs to patients while greatly reducing the risk of occupational exposure among health-care workers and caregivers.

Epigallocatechin gallate induces a hepatospecific decrease in the CYP3A expression level by altering intestinal flora

&NA; In previous studies, we showed that a high‐dose intake of green tea polyphenol (GP) induced a hepatospecific decrease in the expression and activity of the drug‐metabolizing enzyme cytochrome P450 3A (CYP3A). In this study, we examined whether this decrease in CYP3A expression is induced by epigallocatechin gallate (EGCG), which is the main component of GP. After a diet containing 1.5% EGCG was given to mice, the hepatic CYP3A expression was measured. The level of intestinal bacteria of Clostridium spp., the concentration of lithocholic acid (LCA) in the feces, and the level of the translocation of pregnane X receptor (PXR) to the nucleus in the liver were examined. A decrease in the CYP3A expression level was observed beginning on the second day of the treatment with EGCG. The level of translocation of PXR to the nucleus was significantly lower in the EGCG group. The fecal level of LCA was clearly decreased by the EGCG treatment. The level of intestinal bacteria of Clostridium spp. was also decreased by the EGCG treatment. It is clear that the hepatospecific decrease in the CYP3A expression level observed after a high‐dose intake of GP was caused by EGCG. Because EGCG, which is not absorbed from the intestine, causes a decrease in the level of LCA‐producing bacteria in the colon, the level of LCA in the liver decreases, resulting in a decrease in the nuclear translocation of PXR, which in turn leads to the observed decrease in the expression level of CYP3A. Graphical Abstract Figure. No caption available.

Evaluation of Enteral NutrientFlavor and Rating due toDifferences in Form

Aims: It is necessary for medical staff to fully understand disparities in the comprehensive evaluation of enteral nutrients due to differences in their physical form. In this study, we compared the overall rating of each enteral nutrient with respect to form and examined the factors that influence their overall evaluation. Methods: Sensory tests were conducted on 261 pharmaceutical students using the Sematic Differential method. Comparison of comprehensive evaluations for each form of enteral nutrient was carried out for liquids (room temperature, warm, cold), jelly (solid), and mousse (semi-solid) forms. Additionally, factors influencing the comprehensive evaluation of enteral nutrients were investigated using covariance structure analysis. Results: Overall evaluation of each enteral nutrient form showed the jelly was rated highest (2.57 ± 1.49), followed by the warm liquid (2.53 ± 1.29), cold liquid (2.42 ± 1.20), room temperature liquid (2.26 ± 1.20), and the mousse (1.93 ± 1.07). From the result of factor analysis, four factors (flavor, richness, presence, and texture) were extracted. Covariance structure analysis of factors affecting the overall rating revealed that flavor had a significant influence (fitness index: GFI=0.908, AGFI=0.878, RMSEA=0.074, AIC=912.742). Conclusion: Differences in the form of enteral nutrients affected the overall satisfaction of patients. It is important for medical staff, including pharmacists, to deepen their understanding of factors related to the overall rating of enteral nutrients in order to meet the needs of patients.

Changes in the Pharmacokinetics of Phenytoin in Dextran Sulfate Sodium–Induced Ulcerative Colitis in Mice

We previously demonstrated that the expression levels of drug-metabolizing enzymes, cytochrome P450 (CYP) enzymes, in the liver are significantly decreased in a murine model of ulcerative colitis (UC). In this study, we investigated changes in the pharmacokinetics of phenytoin, a CYP2C substrate drug, in the presence of UC. Colitis was induced by feeding male mice 3.5% dextran sulfate sodium (DSS) dissolved in drinking water for 10 days. The messenger RNA (mRNA) expression of CYP2C29 and CYP2C37 and the protein expression of CYP2C in the liver were evaluated via real-time reverse transcription–polymerase chain reaction and Western blotting, respectively. In DSS-treated animals, both mRNA and protein expression levels of CYP2C in the liver were significantly reduced relative to those in control animals (by 20%-40%). Phenytoin (30 mg/kg) was administered orally in a single dose to mice, and plasma concentrations were measured. Plasma concentrations of phenytoin were higher in the DSS-treated group than in the control group at 12, 24, and 36 hours after administration. Animals given DSS also exhibited a higher area under the plasma concentration–time curve extrapolated to infinity (AUCinf, 315 μg·h/mL), a delayed elimination half-life (T 1/2, 8.1 hours), and a decreased body clearance (CL/F, 3.52 mL/h) compared with that of control animals (AUCinf, 215 μg·h/mL; T 1/2, 3.6 h; CL/F, 5.58 mL/h). This study indicated that the presence of UC decreases CYP2C expression levels in the liver, thereby delaying the metabolism of CYP2C substrates, including phenytoin, and increasing blood concentrations of these substrates.