Yoshinori Itoh

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.

Preparation of a fast dissolving oral thin film containing dexamethasone: A possible application to antiemesis during cancer chemotherapy

We prepared fast dissolving oral thin film that contains dexamethasone and base materials, including microcrystalline cellulose, polyethylene glycol, hydroxypropylmethyl cellulose, polysorbate 80 and low-substituted hydroxypropyl cellulose. This preparation showed excellent uniformity and stability, when stored at 40 degrees C and 75% in humidity for up to 24 weeks. The film was disintegrated within 15s after immersion into distilled water. The dissolution test showed that approximately 90% of dexamethasone was dissolved within 5 min. Subsequently, pharmacokinetic properties of dexamethasone were compared in rats with oral administration of 4 mg dexamethasone suspension or topical application of the film preparation containing 4 mg dexamethasone to the oral cavity. Pharmacokinetic parameters were similar between the two groups in which C(max) (h), T(max) (microg/mL), AUC (microg/mL/h) and half-life (h) were 12.7+/-6.6 (mean+/-SD, N=10), 3.4+/-1.4, 93.6+/-37.8 and 1.66+/-0.07, respectively, for oral suspension and 13.3+/-4.0, 3.2+/-1.0, 98.0+/-22.3 and 1.65+/-0.06, respectively, for film preparation. These findings suggest that the fast dissolving oral thin film containing dexamethasone is likely to become one of choices of dexamethasone preparations for antiemesis during cancer chemotherapy.

Sphingosine Kinase Isoforms Regulate Oxaliplatin Sensitivity of Human Colon Cancer Cells through Ceramide Accumulation and Akt Activation

The relationship between sphingosine kinase (SPHK), cellular ceramide concentration and chemosensitivity was investigated in human colon cancer cell lines. Among nine colon cancer cell lines, SPHK1 and SPHK2 activity and protein expression was highest in RKO cells and lowest in HCT116 cells. A viability assay revealed that HCT116 cells were sensitive to the effects of oxaliplatin (l-OHP), whereas RKO cells were resistant to those of l-OHP. Treatment with 5μg/ml l-OHP induced a marked time-dependent increase in various ceramides (C16, C24, C24:1) in HCT116 cells but not in RKO cells, as indicated by liquid chromatography/mass spectrometry. The increase in ceramide and caspase activation induced by l-OHP in the sensitive HCT116 cells was abolished by pretreatment with a neutral sphingomyelinase inhibitor, suggesting that the ceramide formation was due to the activation of neutral, rather than acid, sphingomyelinase. In contrast, in l-OHP-resistant RKO cells, treatment with an SPHK inhibitor or SPHK1 and SPHK2 silencing by RNA interference suppressed cell viability and increased caspase activity and cellular ceramide formation after l-OHP treatment. The elevated ceramide formation induced by SPHK inhibition and l-OHP was inhibited by fumonisin B1 but not myriocin, suggesting that ceramide formation was through the salvage pathway. Endogenous phosphorylated Akt levels were much higher in the resistant RKO cells than in the sensitive HCT116 cells. Either SPHK1 or SPHK2 silencing in RKO cells decreased phosphorylated Akt levels and increased p53 and p21 protein levels as well as poly(ADP-ribose) polymerase cleavage in response to l-OHP treatment. These findings indicate that SPHK isoforms and neutral sphingomyelinase contribute to the regulation of chemosensitivity by controlling ceramide formation and the downstream Akt pathway in human colon cancer cells.

Simultaneous determination of eight β-lactam antibiotics in human serum by liquid chromatography-tandem mass spectrometry.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of eight β-lactam antibiotics, including ampicillin, cefazolin, cefepime, cefmetazole, cefotaxime, doripenem, meropenem, and piperacillin, in human serum. Sample specimens were subjected to solid phase extraction (SPE) using Waters Oasis® HLB cartridges (30 mg). Chromatographic separation was performed with a high-resolution octadecyl silica column compatible with hydrophilic compounds, using a gradient of 10mM aqueous ammonium formate containing 0.1% formic acid-methanol. Antibiotics were detected by a triple quadrupole mass spectrometer (MS/MS) with electrospray ionization and quantified by the multiple reaction monitoring mode. A total run time of 13 min was applied. Linearity in the calibration was obtained over a range of 0.1-50 μg/mL of the β-lactam antibiotics, except for doripenem. The lower limit of quantification was 0.005-0.5 μg/mL, using 50 μL serum. The recovery rate exceeded 80.2% for these analytes, except for doripenem (49.1%) and meropenem (62.3%). The present method is applicable to routine therapeutic monitoring of β-lactam antibiotics in clinical practice.

Involvement of both tumor necrosis factor-α-induced necrosis and p53-mediated caspase-dependent apoptosis in nephrotoxicity of cisplatin

We previously reported that necrosis occurs predominantly in porcine renal tubular LLC-PK1 cells, when the cells were exposed transiently to a high concentration of cisplatin. Moreover, we demonstrated that generation of reactive oxygen species and subsequent production of tumor necrosis factor-α (TNF-α) through phosphorylation of p38 MAPK are implicated in the pathogenesis of cisplatin-induced renal cell injury. However, some TUNEL-positive cells appeared in renal proximal tubules of rats after systemic injection of cisplatin, suggesting an involvement of apoptosis. In the present study, we found in LLC-PK1 cells that both apoptosis and necrosis were elicited when the cells were exposed to 200xa0μM cisplatin for 1xa0h followed by incubation for 24xa0h in the presence of 20xa0μM cisplatin. The cisplatin-induced necrosis was largely attenuated by the antioxidant N-acetylcysteine, while apoptosis was prevented by the specific inhibitors for caspases-2, -8, and -3 and a p53 inhibitor pifithrin-α but not by the p38 MAPK inhibitor SB203580. On the other hand, SB203580 attenuated the cisplatin-induced increase in TNF-α production. These findings suggest that p53-mediated activations of caspases-2, -8 and -3 play a key role in cisplatin-induced renal cell apoptosis, while oxidative stress-induced TNF-α synthesis via p38 MAPK phosphorylation contributed to the necrosis.

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

Background:u2002 Antimicrobial stewardship has not always prevailed in a wide variety of medical institutions in Japan.

Polaprezinc prevents oral mucositis associated with radiochemotherapy in patients with head and neck cancer

Oral mucositis is frequent but serious adverse event associated with radiotherapy or radiochemotherapy in head and neck cancer severely impairs health‐related quality of life, leading to poor prognosis due to discontinuation of the therapy. Although a number of compounds have been tested for prophylaxis of oral mucositis, few of them are satisfactory. We investigated the effect of polaprezinc (zinc L‐carnosine), a gastric mucosal protective drug, on radiochemotherapy‐induced oral mucositis, pain, xerostomia and taste disturbance in patients with head and neck cancer. Patients were randomly assigned to receive polaprezinc (n = 16) or azulene oral rinse as the control (n = 15). The incidence rates of mucositis, pain, xerostomia and taste disturbance were all markedly lower in polaprezinc group than in control. Moreover, the use of analgesics was significantly (p = 0.003) less frequent and the amount of food intake was significantly (p = 0.002) higher in polaprezinc group than in control. On the other hand, tumor response rate in patients with neoadjuvant radiochemotherapy was not significantly affected by polaprezinc, in which the response rate (complete plus partial response) was 88% for polaprezinc and 92% for control (p = 1.000). Therefore, it is highly assumable that polaprezinc is potentially useful for prevention of oral mucositis and improvement of quality of life without reducing the tumor response.

A Multi-institutional Study Analyzing Effect of Prophylactic Medication for Prevention of Opioid-induced Gastrointestinal Dysfunction

Objectives:The aim of this study was to evaluate the effectiveness of prophylactic treatment with laxatives and antiemetics on the incidence of gastrointestinal adverse reactions such as constipation, nausea and vomiting in cancer patients who received oral opioid analgesics for the first time. Methods:A multi-institutional retrospective study was carried out, in which 619 eligible hospitalized patients receiving oral opioid analgesics for cancer pain were enrolled from 35 medical institutions. The primary endpoint was the incidence of opioid-induced side effects in patients receiving prophylactic medication. Odds ratios of the incidence of adverse reactions in the absence or presence of premedication obtained from several institutions were subjected to a meta-analysis. Results:Among 619 patients, the incidence of constipation was significantly lower in patients receiving laxatives, including magnesium oxide, as premedication than in those without them (34% vs. 55%, odds ratio=0.432, 95% confidence interval=0.300-0.622, P<0.001). However, the incidence of nausea or vomiting was similar regardless of prophylactic medication with dopamine D2 blockers. The results of the meta-analysis revealed that prophylactic laxatives significantly reduced the incidence of constipation (overall odds ratio=0.469, 95% confidence interval=0.231-0.955, P=0.037), whereas dopamine D2 blockers were not effective in preventing opioid-induced nausea or vomiting. Discussion:We showed evidence for the effectiveness of premedication with laxatives for prevention of opioid-induced constipation. However, premedication with dopamine D2 blockers was not sufficient to prevent nausea or vomiting.

Retrospective cohort chart review study of factors associated with the development of thrombocytopenia in adult Japanese patients who received intravenous linezolid therapy.

BACKGROUNDnLinezolid is an oxazolidinone antibiotic agent active against Gram-positive bacteria. It has been associated with hematologic adverse effects such as thrombocytopenia. Little is known about the mechanism underlying thrombocytopenia in patients who receive intravenous linezolid.nnnOBJECTIVEnThe aim of the present study was to investigate the risk factors associated with the development of thrombocytopenia in adult Japanese patients who received intravenous linezolid therapy.nnnMETHODSnThis was a retrospective review of the medical charts of patients who were treated with linezolid 600 mg IV BID (q12h) between June 2006 and March 2008 at Gifu University Hospital in Gifu, Japan. Data were extracted from the electronic medical records obtained from a central database in the hospital. Thrombocytopenia was defined as a decrease in platelet count of > or = 25% and a final platelet count of <100 x 10(3)/mm3. Risk factors associated with thrombocytopenia in patients who received linezolid were identified via logistic regression analysis.nnnRESULTSnIn total, 42 patients (31 men and 11 women; mean [SD] age, 59.6 [12.8] years [range, 33-85 years]) were included in the study. The mean duration of linezolid therapy was 13.6 (10.1) days, with a range of 3 to 48 days. Seven patients with renal insufficiency received hemodialysis before linezolid infusion. Thrombocytopenia occurred in 7 patients (16.7%). Among the 7 patients with renal insufficiency, 2 patients (28.6%) developed severe thrombocytopenia, requiring platelet transfusion. In univariate analysis, a high daily dose of > or = 22 mg/kg (odds ratio [OR] = 20.25; 95% CI, 2.115-193.9; P = 0.009), low baseline platelet count of <200 x 10(3)/mm3 (OR = 8.437; 95% CI, 1.367-52.06), and lowered creatinine clearance of <30 mL/min (OR = 6.444; 95% CI, 1.136-36.57) were significant factors for thrombocytopenia associated with linezolid therapy; however, in multivariate analysis, only daily dose (> or = 22 mg/kg) was a significant risk factor for thrombocytopenia associated with linezolid therapy.nnnCONCLUSIONSnThe daily dose of > or = 22 mg/kg was a significant risk factor associated with thrombocytopenia in patients who received linezolid therapy. Prospective studies comparing the efficacy and safety profile of linezolid in patients receiving a conventional dose (600 mg q12h) and those receiving a weight-adjusted dose are needed to determine an adequate dose of linezolid, particularly in patients with renal insufficiency or low baseline platelet count.

Neurotropin reverses paclitaxel-induced neuropathy without affecting anti-tumour efficacy

Paclitaxel is a commonly used anticancer drug, but it frequently causes peripheral neuropathy. Neurotropin, a non-protein extract from inflamed rabbit skin inoculated with vaccinia virus, has been used to treat various chronic painful conditions. In the present study, we investigated the effect of neurotropin on the paclitaxel-induced neuropathy in rats. Repeated administration of paclitaxel induced mechanical allodynia, cold hyperalgesia, and motor dysfunction. These neuropathies were mostly reversed by the repeated administration of neurotropin. Furthermore, neurotropin ameliorated the paclitaxel-induced axonal degeneration in cultured PC12 and rat dorsal root ganglion cells, and in rat sciatic nerve. In addition, neurotropin did not affect the microtubule aggregation or anti-tumour effect induced by paclitaxel in the tumour cell lines or tumour cells-implanted mice. These results suggest that neurotropin reverses the paclitaxel-induced neuropathy without affecting anti-tumour activity of paclitaxel, and therefore may be useful for the paclitaxel-induced neuropathy in clinical settings.