Tadashi Sugiyama

Development of porous apatite ceramic for local delivery of chemotherapeutic agents

An experimental study was conducted on a drug delivery system (DDS), using porous apatite ceramics (PAC): hydroxyapatite block (HAb) [Ca10(PO4)6(OH)2] having a porosity of 35-48% and pore size range of 50-300 microm, and beta-tricalcium phosphate block (TCP) [Ca3(PO4)2] having a porosity of 75-80% and pore size range of 100-400 microm, for sustained release of a chemotherapeutic agent. Methotrexate (MTX) was loaded in the pores of PAC blocks by centrifuging the blocks in MTX solution. Impregnation of MTX in PAC blocks (1 cm3) was confirmed by a magnetic resonance imaging (MRI) study using Gadolinium-DTPA enhancement. The MRI showed high signal intensity in the PAC, which was confirmed by dye loading into the pores. To estimate the MTX-releasing capability of the PAC, the blocks were stored in 3 mL of phosphate-buffered saline (PBS) at 37 degrees C and the PBS was replaced every 48 h. The amount of MTX released was assayed by high-performance liquid chromatography. This study showed that MTX-impregnated PAC (0.63-2.25 mg/block) released the drug in a steady manner and maintained its concentration (0.1-1.0 microg/mL) up to 12 days. This concentration is high enough to be effective against tumor cells. Chemotherapeutic agent-impregnated PAC, prepared by simple centrifugation, could be a valuable form of local chemotherapy when used as a strut graft to repair bone defects. This new DDS material could also be used as an adjuvant to extended curettage and provide a means to reduce the recurrence of tumors without risk of systemic toxicity.

In vitro and in vivo characteristics of prochlorperazine oral disintegrating film

Oral disintegrating film containing prochlorperazine, a dopamine D(2) receptor antagonist with anti-emetic property, was newly developed using microcrystalline cellulose, polyethlene glycol and hydroxypropylmethyl cellulose as the base materials. The uniformity of dosage units of the preparation was acceptable according to the criteria of JP15 or USP27. The film showed an excellent stability at least for 8 weeks when stored at 40 degrees C and 75% in humidity. The dissolution test revealed a rapid disintegration property, in which most of prochlorperazine dissolved within 2 min after insertion into the medium. Subsequently, rats were used to compare pharmacokinetic properties of the film preparation applied topically into the oral cavity with those of oral administration of prochlorperazine solution. None of the parameters, including T(max), C(max), area under curves, clearance and steady-state distribution volume was significantly different between oral disintegrating film and oral solution. These findings suggest that the present prochlorperazine-containing oral film is potentially useful to control emesis induced by anti-cancer agents or opioid analgesics in patients who limit the oral intake.

Outcome measurement of extensive implementation of antimicrobial stewardship in patients receiving intravenous antibiotics in a Japanese university hospital

Background:  Antimicrobial stewardship has not always prevailed in a wide variety of medical institutions in Japan.

Heparin-stimulated expression of extracellular-superoxide dismutase in human fibroblasts

Extracellular-superoxide dismutase (EC-SOD) is the major SOD isozyme in the arterial wall and may be important for antioxidation capability of the vascular wall and normal vascular function. EC-SOD is expressed in various cell types in the vascular wall such as fibroblasts, smooth muscle cells and macrophages, and the synthesis of EC-SOD by human fibroblasts is known to be highly responsive to various inflammatory cytokines, although there is no response to oxidative stress. Heparin is a highly sulfated glycosaminoglycan with many functions such as antithrombotic, antilipemic and antiatherosclerotic effects. Another less well-known function of heparin is regulation of protein synthesis. In this study, we measured the induction of EC-SOD after treatment with heparin to understand the role of heparin in the antiatherosclerotic response of fibroblasts. Heparin induced EC-SOD expression at both the mRNA and protein levels. Heparin showed the greatest stimulatory effect and heparan sulfate showed moderate effects. The effect of chondroitin sulfate A was not clear. In contrast, desulfated heparin and chondroitin sulfate C did not increase EC-SOD expression. The stimulatory effect seemed to increase roughly with the degree of glycosaminoglycan sulfation. The enhanced expression of EC-SOD by heparin must contribute to the antiatherosclerotic effect of heparin.

High-performance liquid chromatographic assay of zonisamide in human plasma using a non-porous silica column.

A new method for measuring zonisamide (ZNS) in plasma by high-performance liquid chromatography was developed by using a 2-microm reversed-phase non-porous silica column. ZNS in plasma was first purified with a column extraction technique and injected onto the non-porous silica column. Calibration curve was linear over the concentration range of 1-80 microg/ml in plasma. The recoveries of ZNS added to plasma were more than 95.4% with the coefficient of variation less than 9.0%. We developed a rapid routine method using the non-porous silica column that was accurate and improved solvent consumption in the measurement of ZNS.

The association between risk factors and time of onset for thrombocytopenia in Japanese patients receiving linezolid therapy: a retrospective analysis

Linezolid (LZD) is an oxazolidinone antibiotic that is active against Gram‐positive bacteria including methicillin‐resistant Staphylococcus aureus and vancomycin‐resistant enterococci. The major adverse effect related to its use in humans is reversible myelosuppression, which mostly manifests as thrombocytopenia. This retrospective study was conducted to identify risk factors that might contribute towards the development of thrombocytopenia due to intravenous administration of LZD.

Simultaneous and rapid determination of gefitinib, erlotinib and afatinib plasma levels using liquid chromatography/tandem mass spectrometry in patients with non-small-cell lung cancer.

A simultaneous, selective, sensitive and rapid liquid chromatography/tandem mass spectrometry method was developed and validated for the quantification of gefitinib, erlotinib and afatinib in 250 μL samples of human blood plasma. Diluted plasma samples were extracted using a liquid-phase extraction procedure with tert-butyl methyl ether. The three drugs were separated by high-performance liquid chromatography using a C18 column and an isocratic mobile phase running at a flow rate of 0.2 mL/min for 5 min. The drugs were detected using a tandem mass spectrometer with electrospray ionization using imatinib as an internal standard. Calibration curves were generated over the linear concentration range of 0.05-100 nm in plasma with a lower limit of quantification of 0.01 or 0.05 nm for all compounds. Finally, the validated method was applied to a clinical pharmacokinetic study in patients with nonsmall-cell lung cancer (NSCLC) following the oral administration of afatinib. These results indicate that this method is suitable for assessing the risks and benefits of chemotherapy in patients with NSCLC and is useful for therapeutic drug monitoring for NSCLC treatment. As far as we know, this is the first report on LC-MS/MS method for the simultaneous quantification of NSCLC tyrosine kinase inhibitor plasma concentrations including afatinib. Copyright

Development of Computer-Assisted Biohazard Safety Cabinet for Preparation and Verification of Injectable Anticancer Agents

Background: Medication errors associated with anticancer agents may cause fatal events. Therefore, exact verification of the prescription order and accurate preparation of the mixture of anticancer injections are required for safe management in cancer chemotherapy. Methods: A computer-assisted biohazard safety cabinet was newly developed for verification and preparation of anticancer agents. Using a barcode reader, information on prescription orders was transmitted from an electronic medical record to the computer system installed in the safety cabinet. The computer was controlled using a 3-button foot switch, which avoided interruption of the mixing procedure. A monitor on the cabinet wall displayed the required amounts of anticancer injections and any special information for the dissolution or mixing procedure. The names of anticancer agents were verified using a personal digital assistant and the volume of injection taken, which was automatically converted to weight on the basis of the specific gravity of anticancer solution, was recorded on the computer through a digital scale. Results: Accuracy and efficiency in mixing anticancer injections were compared between procedures with and without the present apparatus. Errors in the amounts were much smaller and the time spent in preparation was significantly shorter using the present apparatus. Conclusions: The present computer-assisted biohazard safety cabinet for preparation of the mixture of anticancer agents is considered to be potentially useful for the safe management in cancer chemotherapy.

Simultaneous high-performance liquid Chromatographic determination of carboplatin, epirubicin hydrochloride and mitomycin C in a Lipiodol emulsion

A novel HPLC method for the simultaneous determination of carboplatin (CBDCA), epirubicin hydrochloride (EPI) and mitomycin C (MMC) was developed in order to determine these drugs in a Lipiodol emulsion for intra-arterial injection and in the medium of a drug-release test of the emulsion. The HPLC conditions included a reversed-phase column and a gradient programme of the mobile phase using 0.01 M phosphate buffer (pH 3.0)-acetonitrile. The accuracies of analysis for each drug added to the emulsion and the drug-release medium were in the ranges 96–104% and 98–108%, respectively. The R.S.D.s in the repeatability of the determination of each drug in the emulsion and in the drug-release medium were < 8% and < 2%, respectively. The method is simple and reliable enough to be utilized for the investigation of drug contents and drug release of the Lipiodol emulsion containing CBDCA, EPI and MMC.

Adenylyl cyclase‐cAMP system inhibits thrombin‐induced HSP27 in vascular smooth muscle cells

We previously reported that thrombin stimulates the induction of heat shock protein (HSP) 27 via p38 mitogen‐activated protein (MAP) kinase activation in aortic smooth muscle A10 cells. In the present study, we investigated the effect of the adenylyl cyclase‐cAMP system on the thrombin‐stimulated induction of HSP27 in A10 cells. Forskolin, a direct activator of adenylyl cyclase, reduced the thrombin‐induced p38 MAP kinase phosphorylation, and significantly suppressed the thrombin‐stimulated accumulation of HSP27. However, dideoxyforskolin, a forskolin derivative that does not activate cAMP, failed to suppress the HSP27 accumulation. Furthermore, dibutyryl‐cAMP (DBcAMP), a permeable analog of cAMP, significantly suppressed the accumulation of HSP27. On the other hand, calphostin C, an inhibitor of protein kinase C (PKC), reduced the thrombin‐induced p38 MAP kinase phosphorylation, and significantly suppressed the thrombin‐stimulated accumulation of HSP27. Moreover, forskolin reduced the p38 MAP kinase phosphorylation induced by the 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA), a PKC‐activating phorbol ester, and significantly suppressed the TPA‐stimulated accumulation of HSP27. These results indicate that adenylyl cyclase‐cAMP system has an inhibitory role in thrombin‐stimulated HSP27 induction in aortic smooth muscle cells, and the effect seems to be exerted on the thrombin‐induced PKC‐ p38 MAP kinase signaling pathway.