Intestinal absorption, organ distribution, and urinary excretion of the rare sugar D-psicose.

BACKGROUND: The purpose of this study was to evaluate intestinal absorption, organ distribution, and urinary elimination of the rare sugar D-psicose, a 3-carbon stereoisomer of D-fructose that is currently being investigated and which has been found to be strongly effective against hyperglycemia and hyperlipidemia. METHODS: This study was performed using radioactive D-psicose, which was synthesized enzymatically from radioactive D-allose. Concentrations in whole blood, urine, and organs were measured at different time points until 2 hours after both oral and intravenous administrations and 7 days after a single oral administration (100 mg/kg body weight) to Wistar rats. Autoradiography was also performed by injecting 100 mg/kg body weight of (14)C-labeled D-psicose or glucose intravenously to C3H mice. RESULTS: Following oral administration, D-psicose easily moved to blood. The maximum blood concentration (48.5±15.6 µg/g) was observed at 1 hour. Excretion to urine was 20% within 1 hour and 33% within 2 hours. Accumulation to organs was detected only in the liver. Following intravenous administration, blood concentration was decreased with the half-life=57 minutes, and the excretion to urine was up to almost 50% within 1 hour. Similarly to the results obtained with oral administration, accumulation to organs was detected only in the liver. Seven days after the single-dose oral administration, the remaining amounts in the whole body were less than 1%. Autoradiography of mice showed results similar to those in rats. High signals of (14)C-labeled D-psicose were observed in liver, kidney, and bladder. Interestingly, no accumulation of D-psicose was observed in the brain. CONCLUSION: D-psicose was absorbed well after oral administration and eliminated rapidly after both oral and intravenous administrations, with short duration of action. The study provides valuable pharmacokinetic data for further drug development of D-psicose. Because the findings were mainly based on animal study, it is necessary to implement human trials to study the metabolism pathway, which would give an important guide for human intake and food application of D-psicose.

Cetuximab-induced skin reactions are suppressed by cigarette smoking in patients with advanced colorectal cancer.

BACKGROUND: Smoking is widely accepted as the most important risk factor for cancer in the modern world. Several constituents of cigarette smoke are known to interact with drug-metabolizing enzymes, potentially affecting the outcomes of drug treatment. Cetuximab (Erbitux(®); Merck Serono) is indicated for the treatment of colorectal cancer with respect to restoring chemosensitivity to irinotecan in irinotecan-resistant patients. The purpose of this study was to determine whether cigarette smoking adversely affects the actions of cetuximab in the treatment of colorectal cancer. METHODS: We studied 56 patients with colorectal cancer who were treated with cetuximab in our hospital during the time period from 2009 through 2010. We compared the adverse reaction rates of 16 patients who smoked (smokers) with those of 38 patients who did not smoke (non-smokers, including 16 patients who never smoked and 22 patients who were former smokers). RESULTS: The incidence of skin reactions after cetuximab treatment was lower in the smokers than in the non-smokers. In addition, the incidence of anorexia was higher in the smokers than in the non-smokers. Within the group of non-smokers, no statistically significant differences were observed between the never smokers and the former smokers with regard to adverse reactions. CONCLUSION: Our findings suggest that cigarette smoking during anticancer treatment with cetuximab-based regimens reduces the skin reaction, which leads to a reduction in the benefit of the treatment; therefore, patients should quit smoking, at least while receiving cetuximab-based treatment.

Prediction of phospholipidosis-inducing potential of drugs by in vitro biochemical and physicochemical assays followed by multivariate analysis.

An in vitro method to predict phospholipidosis-inducing potential of cationic amphiphilic drugs (CADs) was developed using biochemical and physicochemical assays. The following parameters were applied to principal component analysis, as well as physicochemical parameters: pK(a) and clogP; dissociation constant of CADs from phospholipid, inhibition of enzymatic phospholipid degradation, and metabolic stability of CADs. In the score plot, phospholipidosis-inducing drugs (amiodarone, propranolol, imipramine, chloroquine) were plotted locally forming the subspace for positive CADs; while non-inducing drugs (chlorpromazine, chloramphenicol, disopyramide, lidocaine) were placed scattering out of the subspace, allowing a clear discrimination between both classes of CADs. CADs that often produce false results by conventional physicochemical or cell-based assay methods were accurately determined by our method. Basic and lipophilic disopyramide could be accurately predicted as a nonphospholipidogenic drug. Moreover, chlorpromazine, which is often falsely predicted as a phospholipidosis-inducing drug by in vitro methods, could be accurately determined. Because this method uses the pharmacokinetic parameters pK(a), clogP, and metabolic stability, which are usually obtained in the early stages of drug development, the method newly requires only the two parameters, binding to phospholipid, and inhibition of lipid degradation enzyme. Therefore, this method provides a cost-effective approach to predict phospholipidosis-inducing potential of a drug.

Analysis of the inhibitory mechanism of D-allose on MOLT-4F leukemia cell proliferation.

D-Allose, the C-3 epimer of D-glucose, is one of the rare sugars found in nature. In the present study, we have elucidated for the first time that various leukemia cell lines have different susceptibility to anti-proliferative activity of D-allose, and that this difference is related to the difference in induction of thioredoxin interacting protein (TXNIP) expression. We examined 5 leukemia cell lines (MOLT-4F, IM-9, HL-60, BALL-1 and Daudi), and found that MOLT-4F (T-cell lymphoblastic leukemia) had the highest susceptibility to D-allose, and that Daudi (Burkitt's lymphoma) had the lowest. D-Allose significantly slowed the cell cycle progression without causing apoptosis of MOLT-4F cells. Intracellular TXNIP expression was specifically and markedly enhanced in MOLT-4F cells by D-allose treatment, and subsequent increase of p27(kip1), a cell cycle inhibitor, was observed. On the other hand, D-allose did not increase TXNIP and p27(kip1) levels at all in Daudi cells. These results indicate that D-allose suppresses MOLT-4F cell proliferation possibly by the inhibition of cell cycle progression via induction of TXNIP expression.

Peroxidase-like catalytic activity of aqueous- and immobilized-Mn(3+)-octabromo-porphyrins on ion-exchange resin supplied as mimetic of horseradish peroxidase.

In order to explore the capability of metal porphyrins as an alternative of horseradish peroxidase (HRP), HRP-like activity of three manganese-porphyrins (Mn-Ps) and three Mn-octabromo-porphyrins (Mn-OBPs) was examined in both aqueous and immobilized states. It was found that Mn(3+)-octabromotetrakis(1-methyl-pyridinium-4yl)porphine (Mn-OBTMPyP) has an activity of at least 90% of HRP in an aqueous solution. Mn-OBTMPyP exhibited a catalytic activity even in the presence of hydrogen peroxide without suicide reaction. In addition, Mn-OBTMPyP was revealed to function as an alternative to HRP in the quantitative determination of serum uric acid. These results are of great interest because they indicate that metal-octabromo-porphyrins possibly include promising candidates of artificial enzyme capable of substituting for HRP.

Rapid characterization of drug-drug interaction in plasma protein binding using a surface plasmon resonance biosensor.

High-throughput characterization of drug-drug interactions in plasma protein binding was demonstrated by using a surface plasmon resonance (SPR) biosensor. The method used in this study enabled the discrimination between the two modes of binding inhibition, direct competition and negative allosteric effect, which was difficult in conventional SPR approaches. Two theoretical equations were used representing SPR binding response for directly competitive binding or for independent binding. The experimental binding data for human serum albumin was processed by non-linear least squared regression of the equations. By this approach, drug-drug interactions were classified into three modes, direct competition, independent binding, and allosteric interaction, which were almost consistent with previous reports. In addition, dissociation constants were also estimated roughly for direct competition and for independent binding. The analytical throughput was almost as high as in the previous reports; three minutes per injection. This method is a powerful tool for the characterization of drug-drug interaction at an early stage of new drug development.

Effect of carboxyl-group of D-glutamic acid or gamma-carboxy-D-glutamic acid as N-terminal amino acid of (111)in-diethylenetriaminepentaacetic acid-octreotide on accumulation of radioactivity in kidney.

To establish a strategy for developing (111)In-diethylenetriaminepentaacetic acid ((111)In-DTPA)-octreotide, a diagnostic radiopharmaceutical agent for tumors, with reduced non-specific renal radio-accumulation, the compounds having D-glutamic acid (Glu) or gamma-carboxy-D-glutamic acid (carboxy-Glu) as the N-terminal amino acid were examined for in vivo radio-distribution. Compounds carrying Glu and carboxy-Glu containing one and two negative charges, respectively, showed lower renal radio-accumulation than that carrying D-phenylalanine. It was revealed that the introduction of a negative charge reduces the renal radio-accumulation independently from the number of negative charges. The present result can be a clue for the development of (111)In-DTPA-octreotides with reduced the renal radio-accumulation.

Catalytic activity of silica gels bound manganese(III)-porphyrin on oxidative reaction of adrenaline.

To develop a solid catalysis on oxidative reaction of adrenaline (Ad), supports bound metal-tetrakis(4-carboxyphenyl)porphine (M-TCPP) were investigated. Silica gels bound Mn-TCPP were proved to has a superior activity in the oxidation of Ad and be able to serve as a useful oxidase model for Ad.

Peroxidase-like catalytic activity of Mn(3+)-octabromo-tetrakis(4-sulfophenyl)porphine on linoleate hydroperoxide and its analytical application.

To reveal an enzyme-like catalytic activity of metal-octabromo-tetrakis(sulfophenyl)porphines (M-OBPSs), their peroxidease-like catalytic activity on linoleate hydroperoxide (LOOH) were evaluated on the basis of dye-formation in the coloring reaction between N,N-diethylaniline and 4-aminoantipyrine that yields a quinoid-type dye. Among M-OBPSs tested, Mn(3+)-OBPS allowed to produce the largest amount of dye. The optimal conditions of the coloring reaction catalyzed by Mn(3+)-OBPS for the determination of LOOH were determined. A good linear calibration curve was obtained in the concentration range of 0.025-0.4mumole LOOH with good reproducibility (coefficient of variance=1.23%), suggesting that Mn(3+)-OBPS is a good artificial mimesis of the peroxidase for LOOH. In addition, Mn(3+)-OBPS was highly specific for LOOH even in the presence of cumene hydroxyperoxide or hydrogen peroxide. It was revealed that the peroxidase-like activity of Mn(3+)-OBTP is attributable to the redox cycle of Mn(3+)<-->Mn(4+).

Evaluation of the state of active ingredients in pharmaceutical preparations using fourier transform-Raman difference spectra.

To examine the pharmaceutical application of Fourier transform (FT)-Raman spectroscopy, the state of active pharmaceutical ingredients (APIs) in a preparation of several forms was evaluated by investigating the Raman difference spectra between the preparation and excipient. The difference spectra indicated that APIs in alacepril tablets, caffeine sustained-release granules, and quinidine sulfate granules remained unchanged after the manufacturing process. However, the state of sparfloxacin in nanoparticles changed, although it remained unchanged in tablets or powders. These results show that the FT-Raman difference spectrum is expected to be utilized in the field of quality control of crystalline pharmaceutical preparations.

HPLC retention behaviors of pi-electron rich compounds on Ni2+- and Cu2+-phthalocyanine derivatives bound to silica gels in polar eluents.

The effect of the central metal of columns packed with silica gels binding Ni(2+)- and Cu(2+)-phthalocyanine derivatives (Ni-and Cu-PCS(D)s) on the retention behavior of poly-aromatic-hydrocarbons (PAHs) thereof in a polar eluent was examined. The retention factors of PAHs on the Ni- and Cu-PCS(D)s in 80% methanol showed a good linear correlation. The Cu-PCS(D) column exhibited the pi-pi interactions for PAHs, while the Ni-PCS(D) column exhibited the pi-d interactions for PAHs in addition to the pi-pi interaction for PAHs. Further, an investigation of the retention behavior of anthracene derivatives having different substituents revealed that the Ni- and Cu-PCS(D) columns could recognize the differences of substituents only in a polar eluent.

HPLC retention behaviors of poly-aromatic-hydrocarbones on Cu(II)-octabromotetrakis(4-carboxyphenyl)porphine derivatives-immobilized aminopropyl silica gels in polar and non-polar eluents.

As one of approaches of developing novel HPLC stationary phases, we prepared Cu-octabromotetrakis(4-carboxyphenyl)porphine derivative-immobilized silica gels (Cu-OBTCPP(D)), and evaluated the availability of the resultant Cu-OBTCPP(D) as a stationary phase for separation of poly-aromatic-hydrocarbons (PAHs) and their related compounds. A Cu-OBTCPP(D) column was revealed to have an ability to separate simple PAHs and be useful as a stationary phase in both polar and non-polar eluents. The retention property of the Cu-OBTCPP(D) column was evaluated in various comparative experiments using commercially available columns. In comparison with 2-(1-pyrenyl)ethyl dimetylsilyl silica gel column (PYE column) regarding the retention behavior for PAHs etc., the Cu-OBTCPP(D) column showed stronger interactions involving pi electron in non-polar eluent than PYE column. In comparison with a pentabromobenzyloxy propylsilyl silica gel column (PBB column) regarding the influence of bromination, the Cu-OBTCPP(D) column was affected differently from the PBB column. In comparison with nitrophenylethyl silica gel column (NPE column) regarding the retention behavior for compounds having a dipole in a non-polar eluent, the Cu-OBTCPP(D) column showed electrostatic interactions such as dipole-dipole interaction equivalent to or larger than the NPE column.

Peroxidase-like catalytic activity of Mn- and Fe-tetrakis(4-carboxyphenyl)porphines bound to aminopropyl-glass bead in oxidative reaction of heterocyclic amines.

Fe- or Mn-tetrakis(4-carboxyphenyl)porphine (Fe- and Mn-TCPP) bound to aminopropyl-glass bead (Fe- and Mn-TCPP(g)s) was examined for the peroxidase (POD)-like function in order to develop a solid catalyst which can exhibit POD-like activity without adsorbing heterocyclic amines (HCAs). Mn-TCPP in aqueous solution had only a slight POD-like catalytic activity on HCAs (IQ and MeIQ). As for Fe-TCPP, it was impossible to examine the POD-like activity since it reacted with hydrogen peroxide in a liquid reaction system. However, both Fe- and Mn-TCPP when immobilized on aminopropyl-glass bead via peptide bond (Fe- and Mn-TCPP(g)s), catalyzed the oxidative reaction of mutagenic HCAs with hydrogen peroxide. The catalytic activity of Fe- and Mn-TCPP(g)s was investigated in more detail using as a substrate IQ and MeIQ which were oxidized more rapidly among the tested HCAs. Consequently, the optimal conditions for the oxidative reaction catalyzed by Fe- and Mn-TCPP(g)s were determined. In addition, ESI-mass and absorption spectra of oxidation products of IQ and MeIQ showed that they are dimers. Thus, it was demonstrated that a solid catalyst with POD-like activity can be obtained by immobilizing Fe- and Mn-TCPPs on aminopropyl-glass beads.

Effect of octabromination of a tetrakis(4-carboxyphenyl)porphine derivative bound to silica gels on HPLC retention behaviors of polyaromatic hydrocarbons.

The effect of bromination of Cu-porphyrin-derivative-immobilized silica gels (Cu-TCPP(D)) was examined by comparing the retention behaviors of polyaromatic hydrocarbons (PAHs) on Cu-TCPP(D) and Cu-octabromotetrakis(4-carboxyphenyl)porphine-derivative-immobilized silica gels (Cu-OBTCPP(D)) columns. It was revealed that bromination affects strongly the pi-pi electron interactions caused from hydration energy in a polar eluent (80% methanol) possibly as a result of a destruction of planar structure of porphine-ring by bromination. It was also revealed that bromination enhances pi-d interactions as well as the pi-pi electron interactions in a broad sense (e.g., dispersion forces) in a non-polar eluent (n-hexane). However, the bromination did not exert much influence on electrostatic interactions caused from polarization of mono-halogenated benzenes.

Monitoring the content of reticulocyte hemoglobin (CHr) as the progression of anemia in nondialysis chronic renal failure (CRF) patients.

BACKGROUND: We previously showed that the content of reticulocyte hemoglobin (CHr) is a reliable measure of iron status in chronic dialysis patients with erythrocytopoiesis. The CHr was significantly correlated with conventional parameters of iron deficiency in dialysis patients. We attempted to utilize the measurement of CHr levels to monitor iron status and clarify the changes in iron levels that occur as renal anemia progresses in patients with chronic renal failure (CRF). METHODS: We measured CHr, iron parameters, and the intrinsic erythropoietin (EPO) concentration in nondialysis CRF patients who visited our outpatient clinic (n=211). Iron deficiency was defined according to the transferrin saturation (TSAT) and ferritin levels. Conventional red blood cell parameters and CHr levels were measured using an ADVIA120 autoanalyzer (Bayer Medical, USA). RESULTS: The mean CHr value of the nondialysis CRF patients (creatinine clearance less than 70 mL/min) was 32.3 pg, which was not significantly different from that of the dialysis patients. Significant correlations were found between CHr and ferritin levels (r=0.042, p<0.0403) and CHr and TSAT levels (r=0.040, p<0.0157). A positive correlation was observed between the CHr and serum creatinine levels. Nondialysis CRF patients treated with recombinant human EPO (rHuEPO) at a dose of 24,000 U/month exhibited lower CHr levels, compared with those of other patients who received less than 24,000 U/month. CONCLUSION: CHr is an easily measurable and trustworthy marker of iron status in nondialysis CRF patients. Moreover, the CHr level was also sensitive to iron alterations in nondialysis CRF patients receiving rHuEPO treatment, and thus, the CHr value could likely provide useful information regarding the need for iron supplementation.

Effect of carboxylation of N-terminal phenylalanine of (111)in-DTPA (diethylenetriaminepentaacetic acid)-octreotide on accumulation of radioactivity in kidney.

For purpose of reducing renal accumulation of radioactivity of a known radiopharmaceutical agent, i.e., (111)In-DTPA (diethylenetriaminepentaacetic acid)-D-Phe(1)-octreotide, a derivative in which p-carboxy-L-phenylalanine is substituted for D-Phe(1) was synthesized. Biodistribution study of the resultant compound having carboxy-substituted L-Phe(1) revealed that the renal accumulation was significantly lower than that of control compound having unsubstituted L-Phe(1), demonstrating that the presence of negative charge on the N-terminal amino acid of octreotide is effective to reduce the renal accumulation. This effect can be attributed to the reduction of lipophilicity and also the repulsive force arisen from the negative charge of renal brush border membrane.

[Measuring the content of reticulocyte hemoglobin (CHr) in predialysis chronic renal failure (CRF) patients].

We showed that the content of reticulocyte hemoglobin (CHr) is a reliable measure of iron status with regard to erythrocytopoiesis in chronic dialysis status. The mean CHr level was 32.3 +/- 2.2 pg in dialysis patients and CHr was significantly correlated with the conventional parameters of iron deficiency. We aimed to utilize the measurement of CHr levels to monitor iron status in clinical practice. We measured CHr, iron parameters, and the intrinsic EPO concentration in non-dialysis CRF patients to clarify the alterations in CHr levels that occur as renal anemia progresses. CRF patients who visited our out-patient clinic (n = 189) were included in the study. Iron deficiency was defined by the transferrin saturation and ferritin levels. Conventional red blood cell parameters and CHr levels were measured using an ADVIA120 autoanalyzer (Bayer Medical, USA). The mean CHr value of the non-dialysis patients (creatinine clearance less than 70 ml/min) was 32.7 pg, which did not differ significantly from that of the dialysis patients. Significant correlations were found between CHr and TSAT (r = 0.032, p < 0.0177), unlike the correlation with intrinsic EPO levels. Overall, 11% of the patients were diagnosed as having iron deficiency. There was a positive correlation between CHr and serum creatinine levels. Non-dialysis CRF patients treated with rHuEPO at the dose of 24,000 U/month showed different CHr levels compared with other patients (less than 24,000 U/month). It is possible that rHuEPO treatment in non-dialysis patients affects iron dynamics. In conclusion, CHr is an easily measurable and reliable marker of iron status in non-dialysis CRF patients. Moreover, the CHr level was also sensitive to iron alternations in non-dialysis CRF patients under rHuEPO treatment. Accordingly, if long-acting EPO is available for non-dialysis CRF patients, the CHr value is likely to be indicative of the need for iron supplementation.