Effect of ITO surface treatment on organic light emitting diodes.

Performance of organic light emitting diodes with structure of ITO/NPB/NPB:Ir(piq)3/Alq3/Al was studied by inserting MoO3 hole injection layer (HIL) and using differently cleaned indium tin oxides (ITOs). High luminance and quantum efficiencies were obtained using HIL and highly cleaned ITO. High power efficiency was obtained using HIL and conventionally cleaned ITO, while low driving voltage was obtained using highly cleaned ITO without HIL.

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.

[Measurement of amount of fentanyl remaining in used patches: investigation of clinical factors affecting the remaining amounts in 4 patients].

Although fentanyl patches (FP) designed to sustain plasma fentanyl concentrations for 3 days are used in many patients for continuous relief of moderate to severe cancer pain, there are some cases in which effective pain relief is sustained less than for 3 days, and in which plasma fentanyl concentrations rapidly decrease at the third day after the application. In this study, we measured the amount of fentanyl remaining in FP after continuous 3-days use to clarify some clinical factors that can influence the remaining amounts in 4 patients. Average estimated fentanyl-dermal transfer rates of the collected 41 patches calculated from their remaining amounts were less than nominal rates (21.2+/-3.4 cf. 25 microg/h (2.5 mg FP); 44.9+/-5.1 cf. 50 microg/h (5 mg FP)). Intra-individual variability was also observed (CV: 6.6-14.3% (2.5 mg FP), 3.9-13.3% (5 mg FP)). The present study suggests that the estimated fentanyl-dermal transfer rates are affected by fever, patients' body mass index and application sites. Although further study is necessary to elucidate factors that can influence the variability in transdermal fentanyl absorption, the approach in this study would contribute to improving appropriate usage of FP.

The validation of column-switching LC/MS as a high-throughput approach for direct analysis of di(2-ethylhexyl) phthalate released from PVC medical devices in intravenous solution.

Health Canada reported recently that medical devices containing di(2-ethylhexyl) phthalate (DEHP) should not be used in the clinical treatment of infants, young boys, pregnant women, and nursing mothers. The risk assessment of DEHP released from PVC medical devices is an important issue for hospitalized patients. In this study, a simple, accurate, low-contamination and high-throughput analytical technique for the determination of DEHP in intravenous (IV) solution was developed using column-switching liquid chromatography/mass spectrometry (LC/MS) with an extraction mini-column. The sample preparation for on-line extraction involved simply mixing IV solution with internal standard as DEHP-d(4) in LC glass vials. The IV fat emulsion drug sample cannot be analyzed directly, hence this sample spiked with DEHP-d(4) solution was extracted by hexane and measured by column-switching LC/MS yielding an average recovery of 92.2% (C.V.=7.8%, n=5). A linear response was found for a variety of drugs tested within the validated range of 0.1 or 0.5-10 microg/ml with correlation coefficients (r) greater than 0.99. These results suggest that this method can assay background exposure to DEHP released from PVC medical devices in the patients. The method was applied to various IV solution samples to establish the first screening method for DEHP released from medical devices with respect to their safety.

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.