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The effects of a propolis extract obtained by supercritical fluid extraction on sensitivity to chemotherapeutic agents were examined in HeLa cells and resistant sublines thereof. In addition, the actions of propolis and caffeic acid phenethyl ester (CAPE), a constituent of propolis, on the multidrug efflux transporter P-glycoprotein/MDR1, were evaluated in paclitaxel-resistant HeLa/TXL cells (MDR1-overexpressing cells). In HeLa cells, the sensitivity to paclitaxel and doxorubicin, substrates of MDR1, was unchanged in the presence of propolis. In HeLa/TXL cells, propolis increased sensitivity to these MDR1 substrates. The accumulation of Rhodamine123, also a substrate for MDR1, by HeLa/TXL cells increased in the presence of 50 microg/mL, but not 10 microg/mL, of the extract. However, the growth inhibition of HeLa/TXL cells by paclitaxel was not changed by CAPE, although the accumulation of Rhodamine123 increased significantly in the presence of 100 microm, but not 1 nM or 1 microm, CAPE. Collectively, the extract was suggested to inhibit the function of MDR1 and to increase the sensitivity to MDR1 substrates in HeLa/TXL cells, effects likely to be caused by constituents other than CAPE.

This study involved 180 hemodialysis (HD) patients using anti-MRSA antibiotics. The subjects were divided into a survival group (n=100) and a dead group (n=80), and the factors affecting the prognosis were investigated and compared between the two groups. Factors examined were age, sex, dry weight (DW), duration of HD, presence of DM, and laboratory data {Alb, BUN, Cr, IP one month before starting administration of anti-MRSA antibiotics, and the maximum CRP, WBC and neutrophil fractions (maxCRP, maxWBC and maxNeut, respectively) from one month before to after starting the administration of anti-MRSA antibiotics}. A decrease in DW, increase in age, presence of DM, decrease in Alb, BUN, Cr and IP (taken as markers of the nutritional status of the HD patients) and increase in maxCRP, maxWBC and maxNeut (taken as inflammatory markers) were significant factors in exacerbating the prognosis of MRSA infections. Further, a decrease in DW and IP, presence of DM and increase in maxCRP were found to be significant factors in death due to MRSA infections, as determined by multiple logistic regression analysis. Also, when the factors of total fat mass (TFM), body mass index (BMI) and estimated-lean body mass (E-LBM) were compared between the two groups, while TMF was not significantly different between them, a decrease in BMI and E-LBM were significantly associated with death due to MRSA infections. Thus, muscle content appears to be a more important factor than TFM. These results suggest that nutritional supervision can play an important role in the prevention of MRSA infections in HD patients.

To improve the communication skills of our students, training involving the participation of simulated patients (SPs) was introduced into the curriculum of the Master' s Clinical Pharmacy Course in the graduate school of Kyoto Pharmaceutical University. In 2002, we carried out this training for the first-year graduate students.The training was initiated under the direction of a facilitator, who set up role-plays between patients and pharmacists in specific scenarios. Next, all the students played the role of either patient or pharmacist with each other and then four students role-played with two SPs for 10 minutes in turn. After the role playing had finished, SPs gave their feedback concerning their impressions of the pharmacists and how they had felt in the role-plays.We also had students fill out questionnaires anonymously before and immediately after the training to obtain their views on communication skill training using SPs. The responses were used to evaluate the effectiveness of the training and clarify the problems.Among the 22 participating students, 19 had some idea about SPs beforehand, suggesting that there was interest in improving communication in the clinical situation. Afterwards, all of the students felt that it was important to have such training and that it had been useful to them. Some students said that they had become aware of the difficulty in communication between patients and pharmacists and the gap between them. Thus, we were able to confirm that training using SPs was very useful for developing the communication skills of pharmacists in the clinical setting.

The purpose of this study is to examine the expression profiles of CYP3A1, CYP3A2, CYP3A9, and CYP3A18 mRNAs as well as multidrug resistance (mdr)1a and mdr1b mRNAs in the liver and small intestine of normal male Wistar rats using a reverse transcription-polymerase chain reaction (PCR). In the rat liver, the PCR products for CYP3A1, CYP3A2, and CYP3A18 were readily detectable, whereas CYP3A9 was slightly and mdr1a and mdr1b barely detected. Surprisingly, no PCR products for CYP3A1 and CYP3A2 were detected in the small intestine, but those for CYP3A9, CYP3A18, and mdr1a were readily detectable, and a faint band for mdr1b was also observed. Both CYP3A9 and CYP3A18 levels were found to be high in the duodenum and decreased from the top to bottom of the gut, indicating regional differences in both CYP3A9 and CYP3A18 expression in the small intestine. In contrast, mdr1a expression increased gradually from the upper to lower intestine. Consequently, it was suggested that drug metabolism in the small intestine of normal rats was mediated by CYP3A9 and CYP3A18 rather than CYP3A1 and CYP3A2. Also, regional differences of CYP3A9, CYP3A18, and mdr1a expression were found in the small intestine. The distributions of CYP3A9 and CYP3A18 were different from the distribution of mdr1a, suggesting the cooperative action of drug clearance pathways. This information is important to drug metabolism research based on ex vivo and in vivo studies using rats.

A steroid xenobiotic receptor (SXR) is involved in the induction of MDR1/P-glycoprotein. MDR1 up-regulation by digoxin was previously demonstrated in human colon adenocarcinoma Caco-2 cells, but the participation of SXR remains unclear. Herein, the participation of SXR in MDR1 up-regulation was examined using reverse transcription-polymerase chain reaction in Caco-2 cells, and digoxin-tolerant cells (Caco/DX) as well as human colon carcinoma LS180 cells, which expressed SXR. MDR1 mRNA expression in Caco-2 or LS180 cells was increased by exposure to 1 μM digoxin for 24 h, in a concentration-dependent manner, but SXR mRNA decreased concentration-dependently and was undetectable or significantly lower at 1 μM digoxin, indicating antithetical changes in MDR1 and SXR mRNA expression. Moreover, the MDR1 mRNA level was higher in Caco/DX cells than Caco-2 cells, whereas the SXR mRNA level was lower in Caco/DX cells. Consequently, digoxin was demonstrated to up-regulate MDR1 mRNA and simultaneously down-regulate SXR mRNA expression.

To examine whether cisplatin affects the multidrug transporter MDR1/P-glycoprotein in the kidneys, the effects of cisplatin on cell sensitivity to an anticancer drug, MDR1 function and expression were examined by assessing the growth inhibition by the MDR1 substrate paclitaxel, the uptake and efflux of the MDR1 substrate Rhodamine123 and the level of MDR1 mRNA, respectively. Porcine kidney epithelial LLC-PK1 cells were used, as they have a structure and function similar to those of renal proximal tubular cells and physiologically express low levels of MDR1. The growth inhibitory curve of LLC-PK1 cells by paclitaxel was shifted to a higher concentration range by pretreatment with 1 micro M cisplatin for 48 h. The uptake and efflux of Rhodamine123 were significantly reduced and enhanced, respectively, by pretreatment with 1 micro M cisplatin for 48 h. This enhanced efflux was suppressed by the representative MDR1 substrate/inhibitor ciclosporin. The expression of MDR1 mRNA was increased by the existence of cisplatin for 48 h. These observations taken together suggested that the transient exposure to cisplatin could cause the up-regulation of MDR1 in LLC-PK1 cells.

For the development of a practical training system to effectively teach sterilization techniques, we conducted on unregistered questionnaire survey of the undergraduate student's view about the training practice for glass ample cutting, and then evaluated and discussed the introduction to practical training of pharmaceutical health care and sciences for the third-grade undergraduate students. Among 96 third-grade undergraduate students, 54 students (56%) had some experience in cutting glass amples while the remaining students did not. Twenty-six of the 54 students with some experience (48%) had some anxiety regarding glass ample cutting, while only 13 of the 42 inexperienced students (31 %) had such anxiety. Twelve of the 13 inexperienced students overcame some anxiety against glass ample cutting. Moreover, 87 of 96 students (91%) considered that receiving practice in glass ample cutting was necessary for them. Consequently, the training programs on glass ample cutting were found to be appropriate and useful for students to develop sufficient practical skills and accurate ability in sterilization techniques. As a result, we are now preparing to introduce a training program for glass ample cutting in addition to the regular practical training of pharmaceutical health care and sciences at Kyoto Pharmaceutical University.

We retrospectively examined the effects of the combination of zonisamide (ZNS) on the serum valproate (VPA) concentrations in 10 epileptic patients. The serum VPA concentrations at a steady state in VPA and ZNS combination therapy was about 1.1 times as high as those in VPA monotherapy (p

Anthracycline antibiotics are very effective neoplastic agents widely used clinically. However, because of their many adverse effects (e.g. cardiotoxicity, leukopenia and alopecia), their clinical use has been limited. In order to minimize their adverse effects in clinical cancer chemotherapy, anthracyclines must be selectively transported into tumor cells. If there are differences in transport characteristics between tumor and normal cells, it should be possible to establish a strategy for selectively delivering anthracyclines to tumor cells on the basis of the differences. In human cultured leukemia HL60 cells, as tumor cells, and human fresh mononuclear cells, as normal cells, doxorubicin, pirarubicin, daunorubicin and idarubicin were incorporated via a common carrier-mediated system, but the carriers were different in the two cell types. In HL60 cells, it was indicated that a nucleoside transport system contributed, at least in part, to the transport of doxorubicin and pirarubicin, but not daunorubicin and idarubicin, and its contribution to pirarubicin transport was found in other tumor cells, i.e. mouse ovarian sarcoma M5076 and Ehrlich ascites carcinoma cells. On the other hand, in mononuclear cells, there was no involvement of a nucleoside transport system for the four anthracyclines examined. Therefore, we thought that with the modification of an anthracycline molecule as a substrate for the nucleoside transport system, the anthracycline could be delivered selectively to tumor cells.

The possibility of pharmacokinetic interactions between Saiko-ka-ryukotsu-borei-to extract powder (TJ-12), a widely used traditional Chinese herbal (Kampo) medicine, and carbamazepine (CBZ), an important anti-epileptic drug, was examined in rats. There were no significant differences in the serum protein binding of CBZ and carbamazepine-10, 11-epoxide (CBZ-E), its active metabolite, at two concentrations (1 and 10 Bg/ml) between two groups pretreated orally with the vehicle and TJ-12 suspension (1 g/kg/d, p.o.) for 1 week. One-week repeated pretreatment with TJ-12 (1 g/kg/d) did not influence liver weight, contents of cytochromes P450 and b5 in hepatic microsomes or the formation rate of CBZ-E from CBZ by its microsomes, while pretreatment with phenobarbital (80 mg/kg/d, i.p.) significantly increased these paramenters. Neither a single nor 1-week repeated oral pretreatment with TJ-12 (1 g/kg/d) affected the plasma concentration-time profile and any pharmacokinetic parameter of CBZ or CBZ-E after oral administration of CBZ (50 mg/kg). These results indicated that oral co-administration of TJ-12 with CBZ has no effect of the pharmacokinetics of CBZ or CBZ-E in rats. Concomitant treatment with TJ-12 and CBZ appears to be pharmacokinetically safe in humans.

We have compared the membrane transport and antitumor activity of pirarubicin with those of doxorubicin in M5076 ovarian sarcoma, which exhibits low sensitivity to doxorubicin. Pirarubicin was rapidly taken up by M5076 cells and the intracellular concentration of pirarubicin reached more than 2.5-fold that of doxorubicin. In terms of the 50% cell growth-inhibitory concentration in vitro, pirarubicin was more effective than doxorubicin. Thus, the intracellular concentration influenced the cytotoxicity of these anthracycline agents. On comparison of the nuclear uptake of pirarubicin and doxorubicin, the nucleus/cell ratio of pirarubicin was found to be about 40%, whereas that of doxorubicin reached more than 80%. As the intranuclear concentration of pirarubicin is dependent on nuclear transport, the increases in not only cell membrane transport, but also nuclear membrane transport contributed to the enhancement of the efficacy of pirarubicin. In M5076 solid tumor-bearing mice, pirarubicin reduced the tumor weight to 60% of the control level, although doxorubicin had no effect. These results were supported by the intracellular uptake of pirarubicin. Moreover, theanine, which inhibited the pirarubicin efflux from M5076 cells, increased by 1.3-fold the pirarubicin concentration in the tumor and enhanced the therapeutic efficacy of pirarubicin 1.7-fold. In conclusion, our results suggest that an increase in the concentration of an anthracycline derivative in tumor cells due to alteration of cell membrane transport results in enhancement of the antitumor activity.

Background We previously found that ticlopidine inhibits the proliferation of cultured rat mesangial cells that is induced by fetal bovine serum. This study was designed to examine the effects of ticlopidine on platelet-derived growth factor (PDGF)-induced DNA synthesis and mitogen-activated protein (MAP) kinase activation in such mesangial cells to clarify the mechanism of the antiproliferative action.

The effect of two anti-platelet drugs, ticlopidine and dilazep, on the fetal bovine serum (FBS)-induced DNA synthesis of cultured rat renal mesangial cells was assessed by means of an [3H] thymidine incorporation assay. Each drug inhibited the 2% FBS-induced [3H] thymidine incorporation in a concentration-dependent manner, similar to the inhibition of dipyridamole. The [3H] thymidine incorporation was significantly suppressed by the treatment of more than 1 pM ticlopidine or dilazep. It was thus suggested that ticlopidine and dilazep, might prevent the progression of such glomerular diseases as proliferative glomerulonephritis, at least in part, by suppressing mesangial cell proliferation.

We studied the transport mechanism of pirarubicin (THP) in HL60 and its THP-resistant (HL60/THP) cells, which showed no expression of mdr1 mRNA on Northern blot analysis. Under physiological conditions, the uptake of THP by both types of cell was time- and temperature-dependent. The amount of drug transport in the resistant cells was significantly less than that in the parent cells within 3 min of incubation. THP uptake was significantly higher in the presence than in the absence of 4 mM 2,4-dinitrophenol (DNP) in glucose-free Hanks' balanced salt solution in both HL60 and HL60/THP cells and the increases were approximately equal. In the presence of DNP, the uptake of THP by both types of cell was concentration-dependent, and there were no significant differences in the apparent kinetic constants (Michaelis constant (Km), maximum velocity (Vmax) and Vmax/Km) for THP uptake between HL60 and HL60/THP cells. Additionally, THP transport was competitively inhibited by its analogue doxorubicin. The efflux of THP from HL60/THP cells was significantly greater than that from HL60 cells, and the release from both types of cell was completely inhibited by decreasing the incubation temperature to 0 degrees C and by treatment with DNP in glucose-free medium. In contrast, the P-glycoprotein inhibitors verapamil and cyclosporin A did not inhibit THP efflux. However, genistein, which is a specific inhibitor of multidrug resistance-associated protein (MRP), increased the THP remaining in the resistant cells, and the value was approximately equal to that of the control group in the sensitive cells. These results suggest that THP is taken up into HL60 and HL60/THP cells via a common carrier by facilitated diffusion, and then pumped out in an energy-dependent manner. Furthermore, the accelerated efflux of THP by a specific mechanism, probably involving MRP, other than the expression of P-glycoprotein, resulted in decreased drug accumulation in the resistant cells, and was responsible, at least in part, for the development of resistance in HL60/THP cells.

We examined the transport mechanisms of daunorubicin (DNR) and doxorubicin (ADR) in HL60 and HL60/THP cells which were the non-P-glycoprotein-mediated resistant clone of the parent HL60 cells and showed a low degree of resistance, and compared them with those of pirarubicin (THP). In both lines, it appeared that the uptakes of DNR and ADR were time-, temperature- and concentration-dependent and energy independent, and the transport of DNR consisted of saturable and nonsaturable components. They were pumped out from the cells time-, temperature- and energy-dependently. There were no differences in the accumulation amount of either DNR or ADR between HL60 and HL60/THP cells. Comparing the transport of DNR or ADR with that of THP, the uptake amounts of DNR and THP were approximately equal, and were greater than that of ADR in both types of cell. In cis-inhibition experiments, DNR inhibited the THP uptake noncompetitively in the parent and resistant cells, in contradiction of the previously reported result in which ADR showed competitive inhibition (Nagasawa, K. et al., Cancer Chemother. Pharmacol., in press). The THP accumulation appeared to be increased by preload of DNR and ADR, indicating a counter transport. Thus, DNR and ADR as well as THP might be incorporated via a common carrier-mediated transport system, but DNR uptake in part appeared to follow a nonsaturable transport, and its binding site in the carrier might differ from that of THP and ADR in both HL60 and HL60/THP cells.

This study was conducted to determine the effect of clarithromycin (CAM) on the bioavailability of cyclosporin (CYA) in rats, and to compare its effect with that of erythromycin (EM). The area under the blood CYA concentration-time curve (AUC i.v. ) values after intravenous administration of CYA (2 mg/kg) in combination with CAM or EM (100 mg/kg, p.o.) were significantly increased compared with those of CYA alone, suggesting that there was metabolic inhibition of CYA in the liver by CAM or EM. The time to reach the peak concentration after oral administration of CYA (10 mg/kg) tended to be longer with increasing doses of both CAM and EM (10 and 100 mg/kg, p.o.). Each AUC p.o. value for the CAM or EM coadministration group, except the EM (100 mg/kg) coadministration group (about 77% increase), was comparable to that for the CYA alone group. Both CAM and EM (10 and 100 mg/kg, p.o.) were shown to delay gastric emptying in a dose-dependent manner. The gastric emptying in the group treated with CAM (100 mg/kg) was significantly lower than that with EM (100 mg/kg). It is suggested that CAM as well as EM might affect the oral bioavailability of CYA by inhibiting its metabolism and simultaneously by changing the gastrointestinal motility in rats. Thus, caution is recommended when administering CYA concomitantly with CAM to humans.

We studied the transport mechanism of pirarubicin (THP) in mononuclear cells (MNCs) obtained from healthy human donors. The THP uptake was time-, temperature-, concentration- and energy (in part)-dependent. The uptake of daunorubicin (DNR) and doxorubicin (ADR) was also concentration-dependent, and the transport of ADR consisted of saturable and nonsaturable components. In cis-inhibition experiments, ADR inhibited both THP and DNR uptake noncompetitively, while DNR showed competitive inhibition of the uptake of THP. The THP uptake rate appeared to be increased by preloading DNR, indicating a trans-stimulatory effect, but not with ADR. These results suggest that THP and DNR were taken up into MNCs via a common carrier-mediated transport system, but that the carrier of ADR might differ from that of THP and DNR. Furthermore, apparent differences in the affinity for the carrier, transport efficacy and substrate specificity of the transporter between MNCs and the human leukemia cell lines (HL60 and K562) were indicated.

We studied the uptake mechanisms of anthracycline derivatives, pirarubicin (THP), daunorubicin (DNR) and doxorubicin (ADR), in K562 and multidrug-resistant K562/ADM cells, which overexpress a multidrug efflux pump P-glycoprotein (P-gp). The uptake of THP, DNR and ADR by K562 or K562/ADM cells was time-, temperature- and concentration-dependent. The THP and ADR uptake by the parental cells was not affected by treatment with 4 mM 2,4-dinitrophenol (DNP) alone or DNP plus a P-gp specific inhibitor, cyclosporin A (CyA, 10 microM), while the DNR uptake in the DNP treatment group was significantly greater than that in the control group. There was no difference in the uptake of THP between DNP-pretreated K562 cells and DNP plus CyA-pretreated K562/ADM cells. The uptake of DNR or ADR was almost equal in both types of cell treated with DNP alone. Every kinetic constant for THP, DNR and ADR uptake by the sensitive cells was approximately equal to that in the resistant cells, respectively, under the above conditions. THP uptake was noncompetitively inhibited and stimulated on simultaneous treatment and preloading, respectively, of DNR or ADR in each type of cell. ADR showed noncompetitive inhibition of DNR uptake by either type of cell. Therefore, it was suggested that a common carrier-mediated transport system was involved in the uptake of THP, DNR and ADR, and that their binding sites in the carrier might be different from one another in both K562 and K562/ADM cells.

We previously revealed that pirarubicin (THP) was actively taken up by rat polymorphonuclear leukocytes via a carrier-mediated transport system. In the experiment on the effects of the metabolic inhibitors, rotenone, 2,4-dinitrophenol and sodium cyanide significantly decreased the THP transport. However, sodium fluoride (NaF) significantly increased the uptake, and this result is different from that in some reports. Therefore, we examined the action of NaF on THP uptake by the leukocytes to clarify the discrepancy in the effect of NaF on drug transport. The accelerating effect of 30 mM NaF on the THP uptake by the cells had an optimum period of action (15-20 min), and was concentration-dependent (5-30 mM). Thirty mM potassium fluoride, as well as NaF, increased the uptake amount. On the other hand, NaF (5-30 mM) dose-dependently decreased the ATP content in these cells. Additionally, the viable cells in the reaction suspension decreased by about 40% after incubation with 30 mM NaF for 15 min. Observing these leukocytes treated with NaF by optical microscopy, swelling of the cell and an alteration of the nuclei form occurred. On the basis of these results, we speculated that the increased THP transport in polymorphonuclear leukocytes by NaF, probably F-, might be due, at least in part, to an alteration of the morphological form.

The effects of turmeric extracts on the pharmacokinetics of nifedipine were examined in 10 healthy volunteers. An open-label and randomized crossover study was performed at 2-week intervals. In the control experiment, after a 10 h overnight fast, 10 mg of nifedipine (Adalat® capsule) was administered orally and blood was collected at 0, 0.5, 1, 2, 3, 4, 5, 6, and 8 h. In the combination experiment, the volunteers were orally administered 10 mg of nifedipine together with six tablets containing concentrated turmeric extract (480 mg of curcuminoid per six tablets), which is the general daily dose, and blood was sampled as above. The time profile of the plasma concentration of nifedipine in the control was comparable to that in combination with turmeric extract, as were the pharmacokinetic parameters: that is, the mean ratio of turmeric extract/control group (90% confidence interval: CI); C(max), 0.98 (0.95, 1.01) and AUC(0 - ∞) 1.00 (0.98, 1.02). In addition, the volunteers all completed the study without any serious adverse events. Consumption of the turmeric extract did not affect the pharmacokinetics of nifedipine after a single oral administration.

Agaricus blazei Murill (ABM; Japanese name: Kawahiratake or Agarikusutake) extract is a widely used dietary supplement. However, limited information is available on the effects of the extract on the effectiveness of the chemotherapeutic agents. In this study, we examined the effects of ABM extract (Kyowa Wellness Co., Ltd.) on sensitivity to chemotherapeutic agents, paclitaxel and doxorubicin as MDR1/P-glycoprotein substrates, and cisplatin and 5-fluorouracil as non-substrates, in human cervical carcinoma HeLa cells, and paclitaxel-resistant and cisplatin-resistant derivatives (HeLa/TXL and HeLa/CDDP, respectively). The extract had no growth inhibitory effects on HeLa and the resistant cells at concentrations ranging from 7.6 × 10(-4) μ g/ml to 8.0 × 10(2)μ g/ml, indicating no remarkable cytotoxic activity in vitro. In the presence of 0.1, 0.5, and 1 μ g/ml of ABM extract, sensitivity to paclitaxel, cisplatin and 5-fluorouracil did not change in HeLa, HeLa/TXL and HeLa/CDDP cells. However, the extract reduced sensitivity to doxorubicin in HeLa/TXL and HeLa/CDDP cells in a concentration-dependent manner. In conclusion, the concomitant use of ABM extract minimally affected sensitivity to various chemotherapeutic agents in HeLa cells and resistant sublines in vitro.

We performed experiments on the cis-inhibition and trans-stimulation effect on pirarubicin uptake in order to clarify the involvement of a carrier in the pirarubicin, daunorubicin and/or doxorubicin transport systems in rat polymorphonuclear leukocytes. The uptake of daunorubicin and doxorubicin was a saturable concentration-dependent process. Since the apparent kinetic constants, Michaelis constant (Km) and inhibition constant (Ki), were almost comparable, these drugs presented mutually competitive inhibition. Furthermore, the pirarubicin uptake by polymorphonuclear leukocytes was significantly elevated by increasing the preloaded amount of doxorubicin, indicating that there was a trans-stimulation effect on the pirarubicin transport in the leukocytes. These results suggest that carrier-mediated transport might be involved in the uptake of anthracycline derivatives, pirarubicin, daunorubicin and doxorubicin, by rat polymorphonuclear leukocytes.

Two types of mefenamic acid (MA) suppositories were prepared, one with Vosco®, an oleaginous base (Vosco suppository) and another with polyethylene glycol (PEG), a watersoluble base (PEG suppository). The crystallinities of MA in the Vosco and PEG suppositories, the in vitro release behaviors of MA from them, and the pharmacokinetics of MA following their rectal administarations to healthy volunteers were respectively compared. X-ray diffractometry revealed that MA in the Vosco suppository was mainly dispersed in a crystal form, whereas MA in the PEG suppository was disseminated in the amorphous state, with the in vitro release of MA from the PEG suppository being faster. MA in the Vosco or PEG suppository was chemically stable, and the in vitro release behavior of MA from each suppository did not change after storage for 2 months at 5°C. The serum MA maximum concentration (Cmax) and the time to reach Cmax after rectal administration of the PEG suppository appeared to be respectively higher and to be shorter than those of the Vosco suppository. The areas under the serum MA concentration-time curves (AUCs) from zero time to 8 h for the Vosco and PEG suppositories were 3.2 and 4.1 μg·h/ml, respectively, and their values were not significantly different. It was concluded that the PEG suppository presented a faster release characteristic of MA than did the Vosco suppository and that the serum MA concentration profiles arising after administration of these suppositories reflected their release characteristics.

The purpose of this study is to examine the effects of doxazosin, an alpha-adrenoceptor antagonist, on P-glycoprotein/MDR1-mediated multidrug resistance (MDR) and the transport of anticancer drugs. The effects of doxazosin, prazosin, and terazosin on MDR1-mediated MDR were assessed in human cervical carcinoma HeLa cells and the MDR1-overexpressing derivative Hvrl00-6, established by stepwise increases of the vinblastine concentration in the culture medium. The effects of doxazosin on the transcellular transport and intracellular accumulation of [3H]vinblastine, [3H]daunorubicin, and [3H]digoxin, all MDR1 substrates, were evaluated using LLC-GA5-COL150 cell monolayers, established by transfection of human MDR1 cDNA into porcine kidney epithelial LLC-PK1 cells. The sensitivity to vinblastine and paclitaxel of Hvrl00-6 cells was increased at 3.4- and 17.5-fold, respectively, by the addition of 1 microM doxazosin, whereas prazosin and terazosin had weaker or no such effects. Prazosin at 1 microM had a reversal effect on the sensitivity to vinblastine, whereas terazosin had no effect. In transport experiments, doxazosin concentration dependently increased the apical-to-basal transport of radiolabeled drugs in LLC-GA5-COL150 cells, but did not show remarkable effects on the basal-to-apical transport. In addition, doxazosin restored the intracellular accumulation in a concentration-dependent manner in LLC-GA5-COL150 cells. Doxazosin may partly reverse MDR by inhibiting MDR1-mediated transport, making it a candidate lead compound in the development of a reversing agent for MDR.

The aim of this study was to examine the effects of 16 kinds of nonsteroidal anti-inflammatory drugs (NSAIDs) on P-glycoprotein/MDR1 in Caco-2 cells as an intestinal epithelial cell model. Cells were treated with NSAIDs for 24 hours, and then, the expression of MDR1 mRNA was evaluated by reverse-transcriptase polymerase chain reaction. The function of MDR1 in cells pretreated with NSAIDs for 48 hours was evaluated by measuring the cellular amount of rhodamine123, which is a substrate of MDR1. The expression of MDR1 mRNA was increased by diclofenac, fenbufen, indomethacin, and nimesulide and the tended to be increased by meloxicam, mepirizole, and sulindac. However, pretreatment for 48 hours with diclofenac, indomethacin, or nimesulide, but not fenbufen, resulted in a significant increase in the amount of rhodamine123 accumulated. Although NSAIDs without effects on the expression of MDR1 mRNA altered the accumulation of rhodamine123 significantly, the efflux of rhodamine123 from cells was unchanged. In conclusion, the expression of MDR1 mRNA in Caco-2 cells was demonstrated to be increased by treatment with some NSAIDs, although the transport function of MDR1 was unchanged. These findings imply that the NSAIDs did not cause the drug interaction via MDR1 induction.

Sairei-to is a traditional herbal medicine used to complement, and as an alternative to, Western drugs. The aim of this study was to evaluate the pharmacokinetic interactions between Sairei-to and nifedipine (NFP), a substrate for CYP3A, in rats. NFP-oxidizing activity and the pharmacokinetics of NFP were examined after a single or 1-week of administration of Sairei-to (EK-114). NFP-oxidizing activity was enhanced transiently around 24 h after a single administration of EK-114 (1400 mg/kg). In vivo, the first-pass metabolism of NFP increased in the small intestine at 24 h after the administration of EK-114, and this effect disappeared at 72 h. Co-administration of EK-114 tended to inhibit the metabolism of NFP. On the other hand, when EK-114 was given at a high dose (1400 mg/kg) for 1 week, the oxidation of NFP in the small intestine was inhibited, and Cmax and AUC after the oral administration of NFP increased. In addition, a clinical dose of EK-114 (140 mg/kg) did not alter the pharmacokinetics of NFP, regardless of the administration schedule. EK-114 was suggested to affect the metabolism of NFP. However, the CYP3A-mediated pharmacokinetic interaction on the concomitant use of EK-114 may not be clinically significant.

Objective: To achieve a reversal of multidrug resistance (MDR) in cancer chemotherapy, it is crucial to clarify the characteristics of MDR cells generated by various types of chemotherapeutic agents and to find novel targets. Methods: Cisplatin- and paclitaxel-resistant HeLa sublines (HeLa/CDDP and HeLa/TXL, respectively) were established by continuous exposure and their cellular changes were examined based on growth inhibition assays, the transport activity of P-glycoprotein/MDR1, and a RT-PCR analysis of MDR-related factors. Results: HeLa/CDDP cells showed cross-resistance to platinum derivatives, whereas HeLa/TXL cells were resistant to a variety of MDR1 substrates. Transport activity of MDR1 was reduced in HeLa/CDDP cells and the expression of MDR1 was significantly accelerated in HeLa/TXL cells, compared with HeLa cells. In addition, the expression levels of MDR-related transporters (MRP1–5 or BCRP), βtubulin which is a target for taxanes, and apoptosis-regulated factors were comparable among the three cell lines. On the other hand, the mRNA levels of γ-glutamyl transferase, but not γ-glutamyl cysteine synthetase, were higher in HeLa/CDDP cells than in HeLa and HeLa/TXL cells. Conclusions: HeLa/CDDP cells showed decreased activity and expression of MDR1 and overexpression of \( \ifmmode\expandafter\tilde\else\expandafter\sim \fi{\gamma }{\text{-GT}} \) but not \( \ifmmode\expandafter\tilde\else\expandafter\sim \fi{\gamma }{\text{-GCS,}} \) whereas the activity of MDR1 in HeLa/TXL cells was significantly enhanced. Thus, the molecular changes to HeLa cells caused by continuous exposure to cisplatin or paclitaxel were in part clarified, and therefore an understanding of the cellular changes induced by chemotherapeutic agents will be necessary to establish a strategy for reversing MDR.

The popularity of traditional herbal medicine (THM) being used as complementary medicines or alternative medicines is increasing. On the other hand, the development of multidrug resistance (MDR) remains a major hurdle to successful cancer chemotherapy. Some THMs capable of reversing MDR may contribute to the improvement of clinical outcomes in cancer chemotherapy. Herein, 19 kinds of herb were chosen from the ingredients of major THMs, and their effects on the sensitivity to anticancer drugs of tumor cells were investigated using the human cervical carcinoma HeLa cells. Focusing on the major mechanism for MDR, i.e., MDR1/P-glycoprotein, the effects of herbal extracts on its transport function were also examined using a MDR1 substrate Rhodamine123. Glycyrrhizae Radix, Rhei Rhizoma, Scutellariae Radix, Poria, Zizyphi Fructus, Zingiberis Rhizoma (dry), Coptidis Rhizoma, Ephedrae Herba and Asiasari Radix significantly enhanced the sensitivity to a MDR1 substrate paclitaxel, whereas none of the herbal extracts used had any effect on the sensitivity to 5-fluorouracil, which is not a substrate for MDR1. Rhodamine123 uptake was significantly increased by Rhei Rhizoma, Poria or Ephedrae Herba among nine herbal extracts sensitized to paclitaxel. This suggests that the increase in paclitaxel sensitivity by Glycyrrhizae Radix, Rhei Rhizoma, Poria or Ephedrae Herba was caused, in part, by the inhibition of MDR1 function, and the change in paclitaxel sensitivity by the other herbal extracts was not always dependent on this. Collectively, these findings indicate that the combination of anticancer drugs with some herbal extracts contributes to the enhancement of clinical outcomes in cancer chemotherapy.

The effects of Ginkgo biloba leaf extract (GBE), a widely used herbal dietary supplement in Japan, on the pharmacokinetics and pharmacodynamics of nifedipine (NFP), a calcium-channel blocker, were studied using 8 healthy volunteers. Simultaneous oral ingestion of GBE (240 mg) did not significantly affect any of the mean pharmacokinetic parameters of either NFP or dehydronifedipine, a major metabolite of NFP, after oral administration of NFP (10 mg). However, the maximal plasma NFP concentrations in 2 subjects were approximately doubled by GBE, and they had severer and longer-lasting headaches with GBE than without GBE, with dizziness or hot flushes in combination with GBE. The mean heart rate after oral administration of NFP with GBE tended to be faster than that without GBE at every time point. Accordingly, it was concluded that GBE and NFP should not be simultaneously ingested as much as possible, and careful monitoring is needed when administering NFP concomitantly with GBE to humans.

The aim of our study was to investigate the effects of rabeprazole, a proton pump inhibitor, on MDR1 expressed on human colon carcinoma cell line, Caco-2, and MDR1-overexpressing human cervical carcinoma cell line, HeLa cells selected by exposure to 100 nM vinblastine (Hvr100-6 cells). Inhibitory effects of rabeprazole on MDR1-mediated transport of Rhodamine123 were examined in these cells. A thousand micro molar rabeprazole increased Rhodamine 123 uptakes in Caco-2 and Hvr100-6 cells by 68% and 185%, respectively. No significant effects of rabeprazole were observed at the concentration of 1-100 microM. Since rabeprazole did not show any effects on Rhodamine 123 transport via MDR1 at the plasma levels (approximately 1 microM), it was considered that the drug interaction with MDR1 substrates would be minimal even though the interaction occurred in the patients with rabeprazole treatment.

The effects of Ginkgo biloba leaf extract (GBE), one of the most widely used herbal dietary supplements in Japan, on the pharmacokinetics of diltiazem (DTZ), a typical probe of cytochrome P450 (CYP) 3A, were examined in rats. The simultaneous addition of GBE to small intestine and liver microsomes inhibited the formation of N-demethyl DTZ (MA), an active metabolite of DTZ produced by CYP3A, in a concentration-dependent manner, with an IC(50) of about 50 and 182 microg/ml, respectively. This inhibition appeared to be caused, at least in part, by a mechanism-based inhibition. Both the rate of formation of MA and total amount of CYP in intestinal or hepatic microsomes after a single oral pretreatment with GBE (20 mg/kg) decreased transiently. The pretreatment significantly decreased the terminal elimination rate constant and increased the mean residence time, after intravenous administration of DTZ (3 mg/kg). Furthermore, it significantly increased the area under the concentration-time curve and absolute bioavailability after oral administration of DTZ (30 mg/kg). These results indicated that the concomitant use of GBE in rats increased the bioavailability of DTZ by inhibiting both intestinal and hepatic metabolism, at least in part, via a mechanism-based inhibition for CYP3A.

The Caco-2 cell line has been used widely for studying intestinal permeability and several transport functions, and express the multidrug resistance transporter MDR1/P-glycoprotein. Previously, the transient exposure to digoxin for 24h was found to induce MDR1 mRNA in Caco-2 cells. Here, a digoxin-tolerant Caco-2 subline (Caco/DX) was newly established by the continuous exposure of Caco-2 cells to digoxin, and the effects of continuous exposure to digoxin on MDR1 were examined. The 50% growth inhibitory concentration (IC50) values for digoxin in Caco-2 and Caco/DX cells were 17.2 and 81.4 nm, respectively. The IC50 values for paclitaxel, an MDR1 substrate, were 1.0 and 547 nm, respectively, whereas the cytotoxicity of 5-fluorouracil was comparable in both cells. The uptake and efflux of Rhodamine123, an MDR1 substrate, in Caco/DX cells were significantly less and greater, respectively, than those in Caco-2 cells, and these transports were affected by the addition of ciclosporin. The expression of MDR1 mRNA in Caco/DX cells was approximately 2- and 1.7-fold compared with Caco-2 cells and Caco-2 cells treated with 100 nm digoxin for 24 h, respectively. On the other hand, MRP1 mRNA in Caco/DX cells was unchanged. These observations confirmed that the continuous exposure to digoxin, as well as the transient exposure, induced MDR1 in Caco-2 cells.

To clarify the uptake mechanism(s) for statins, we examined whether monocarboxylate transporter (MCT) contributed to the uptake of lovastatin acid by rat cultured mesangial cells. Expression of mRNAs for MCT1, 2, and 4 was confirmed in mesangial cells. The uptake of lovastatin acid by mesangial cells increased with decreasing extracellular pH. There was clear overshooting in lovastatin acid uptake by the ATP-depleted cells in the presence, but not in the absence, of an inwardly directed H(+)-gradient. The representative MCT substrates/inhibitors inhibited the lovastatin acid uptake. In particular, the inhibition of lovastatin acid uptake by L-lactic acid at the concentration of 80 mM reached 70%, and L-lactic acid and valproic acid inhibited the uptake competitively. On preloading of mesangial cells with L-lactic acid or valproic acid, the lovastatin acid uptake was significantly stimulated. The inhibition constant of L-lactic acid for the lovastatin acid uptake was 32 mM, and this value is comparable to the Michaelis constant (>20 mM) of L-lactic acid for MCT4 described elsewhere. These results demonstrate that lovastatin acid was largely taken up by mesangial cells via MCT, and suggest that MCT4 might contribute to lovastatin acid uptake in the cells.

The possibility of pharmacokinetic interactions between Sho-saiko-to extract powder (TJ-9), the most widely used traditional Chinese herbal (Kampo) medicine in Japan, and carbamazepine (CBZ), an important anti-epileptic drug, was examined in rats. There was no significant difference in the protein binding of CBZ in serum obtained before and after the single oral administration of TJ-9. The addition of TJ-9 to normal hepatic microsomes inhibited CBZ-10,11-epoxylase activity in a concentration-dependent manner. Liver weight, amounts of P450 and cytochrome b(5) in hepatic microsomes and the formation of carbamazepine-10,11-epoxide (CBZ-E), an active metabolite of CBZ, by microsomes were not influenced by 2-week repeated oral pretreatment with TJ-9 (1 g/kg/d), although pretreatments with phenobarbital (80 mg/kg/d, i.p.) significantly increased these parameters. The simultaneous oral administration of TJ-9 (1 g/kg) significantly decreased the peak plasma concentration of CBZ and the area under the concentration-time curve of CBZ-E, and lengthened the time to reach the peak concentration of CBZ after oral administration of CBZ. Two-week repeated oral pretreatment with TJ-9, however, did not affect the plasma concentration-time profile or any pharmacokinetic parameter of CBZ or CBZ-E. Also, a single oral administration of TJ-9 (1 g/kg) significantly delayed gastric emptying. These results indicated that the simultaneous oral administration of TJ-9 with CBZ to rats decreased the gastrointestinal absorption of CBZ, at least in part, by delaying gastric emptying, without affecting the metabolism of CBZ.

Because MDR1 (P-glycoprotein) plays an important role in pharmacokinetics such as absorption and excretion of xenobiotics and multidrug resistance, an understanding of the factors regulating its function and expression is important. Here, the effects of digoxin on cell sensitivity to an anticancer drug, MDR1 function, and expression were examined by assessing the growth inhibition by paclitaxel, the transport characteristics of the MDR1 substrate Rhodamine123, and the level of MDR1 mRNA, respectively, using human colon carcinoma Caco-2 cells, which are widely used as a model of intestinal epithelial cells. The sensitivity to paclitaxel, an MDR1 substrate, in Caco-2 cells pretreated with digoxin was lower than that in non-treated cells. The accumulation of Rhodamine123 was reduced by pretreatment with digoxin and its efflux was enhanced. The level of MDR1 mRNA in Caco-2 cells was increased in a digoxin concentration-dependent manner. These results taken together suggested that digoxin up-regulates MDR1 in Caco-2 cells.

We investigated the pharmacokinetics of diclofenac, one of the important analgesics in palliative care, after its intrarectal and intracolostomal administration to rabbits with rectal resection or colostoma construction. In rectal-resected rabbits, its bioavailability after rectal administration was significantly lower than that in normal rabbits, and furthermore that after intracolostomal administration was significantly lower than that in rectal-resected rabbits. This decreased bioavailability in rabbits with rectal resection and colostoma construction was thought to be due to the increased first-pass effect. With increase in the dose up to 1.5-fold, the plasma concentrations in both rectal-resected and colostoma-constructed rabbits increased to the normal rabbit level. These results indicate that the bioavailability of diclofenac sodium after its rectal and intracolostomal administration decreases, and that an increased dose can restore the decreased plasma concentration. There was no difference in the plasma concentration with diclofenac sodium suppositories between administration into the normal rectum and the remaining rectum following colostoma construction, and the remaining rectum was found to be a useful administration route for suppositories. Therefore, it was indicated that when administering diclofenac sodium suppositories to rectal-resected and colostoma-constructed patients, the dose should be increased, because the pharmacokinetics of diclofenac was similar in rabbits and human.

Purpose: We sought to determine whether the de novo resistance of M5076 ovarian sarcoma cells, which show sensitivity to pirarubicin (THP), to doxorubicin (DOX) is due to differences in the transport characteristics between THP and DOX, and the results were compared with those for drug-sensitive Ehrlich ascites carcinoma cells. Methods: The in vitro cytotoxicity of the drugs was assessed by means of the tetrazolium dye assay. Transport experiments were performed by the rapid centrifugation method. Results: In an in vitro cytotoxicity experiment, M5076 cells showed lower sensitivity to DOX than to THP, and the cytotoxicity of THP and DOX toward M5076 cells was lower than toward Ehrlich cells, and these results were similar to those of an in vivo experiment. This was due to the much lower expression of topoisomerase II in M5076 cells than in Ehrlich cells. The amount of intracellular DOX was found to be significantly lower than that of THP in both cell types, and furthermore, little free intracellular DOX was observed in M5076 cells, indicating that the low sensitivity of M5076 cells to DOX was partially a result of the low amount of intracellular DOX. There was no difference in the efflux rate, but there was an apparent difference in the uptake efficiency of the carrier between THP and DOX. Conclusions: These findings suggest that the cytotoxicities of THP and DOX toward M5076 and Ehrlich cells depend, at least in part, on the uptake efficiency of the carrier.

Mesangial cells play an important role in physiologic functions, including the regulation of glomerular filtration, and as a pathogenic factor for proliferative glomerulonephritis. We compared the potencies of the inhibitory effects of simvastatin acid, lovastatin acid, and pravastatin on fetal bovine serum (FBS)-induced proliferation of rat cultured mesangial cells, and examined the correlation between their inhibitory effects and intracellular concentrations. We also investigated the transport of the statins in the cells, and whether or not their intracellular concentrations were determined by their transport characteristics. It appeared that the growth inhibitory effects on FBS-induced proliferation of mesangial cells of simvastatin acid and lovastatin acid were approximately the same, but that of pravastatin was extremely weak compared with the others. The growth inhibitory effects of these agents were suggested to depend, at least in part, on the amount incorporated intracellularly. Simvastatin acid, lovastatin acid, and pravastatin appeared to be taken up by mesangial cells via a common carrier, the uptake capacity being determined by their lipophilicity. Therefore, it was thought that the growth inhibitory effects of the statins partially depended on their carrier-mediated uptake by mesangial cells.

The effects of oral co- and pre-administration of Sho-seiryu-to extract powder (TJ-19, 1 g/kg), a widely used Kampo (traditional Chinese herbal) medicine, on the pharmacokinetics of an anti-epileptic drug, carbamazepine (CBZ), and its active metabolite (carbamazepine-10,11-epoxide, CBZ-E) after oral administration of CBZ (50 mg/kg) were examined in male rats. The simultaneous administration of TJ-19 significantly lengthened the time to reach the peak plasma concentration (Tmax), but did not influence the peak plasma concentration, area under the plasma concentration-time curve or terminal elimination half-life (t1/2). Each parameter for CBZ or CBZ-E with a single pretreatment with TJ-19 was not significantly different from that with the vehicle. Tmax and the elimination rate constant for CBZ were significantly increased by 1-week repeated pretreatment with TJ-19, by 83% (p

Previously, we reported that pirarubicin (THP), an anthracycline, was taken up, at least in part, by both human leukemic HL60 cells and mononuclear cells (MNCs) via a carrier‐mediated system. In this study, the possibility of a contribution of nucleoside transport systems to the uptake of THP by HL60 cells and MNCs was investigated. The experiments were performed after both types of cells had been pretreated with a metabolic inhibitor, 2, 4‐dinitrophenol, to deplete cellular ATP. In HL60 cells, THP uptake was increased and decreased significantly by treatment with equilibrative nucleoside transport inhibitors, nitrobenzylthioinosine (NBMPR), nitrobenzylthioguanosine and dilazep, in the presence and absence, respectively, of an inwardly directed Na+‐gradient. THP uptake by HL60 cells showed an overshoot in the presence of the gradient, and was decreased by treatment of the cells with monensin, indicating that the uptake partially depended on the Na+‐gradient. In HL60 cells in which equilibrative nucleoside transport was inhibited by NBMPR, THP uptake in the presence of the gradient was inhibited by Na+‐dependent concentrative nucleoside transport inhibitors, but no inhibition was observed in the absence of the gradient. In MNCs, conversely, there was no effect of any equilibrative nucleoside transport inhibitor or the Na+‐gradient on THP uptake. These results suggested that THP was taken up, at least in part, via both equilibrative and concentrative nucleoside transport systems in HL60 cells, but not in MNCs.

Transport mechanisms of idarubicin (IDA) in HL60 cells, as leukemia cells, and human mononuclear cells (MNCs), as normal cells, were investigated, and compared with those of its analogs. The uptake of IDA by both cell types was temperature- and concentration-dependent, was inhibited competitively by daunorubicin (DNR) and noncompetitively by adriamycin (ADR), and was stimulated by preloading of the cells with DNR and ADR, indicating the partial involvement of a carrier-mediated mechanism. On pretreatment of the cells with 2,4-dinitrophenol, IDA uptake by HL60 cells increased, but that by MNCs decreased, suggesting that IDA was partially taken up into HL60 cells via an energy-independent carrier system, and into MNCs via an energy-dependent one. We speculated that in HL60 cells the carrier concerned with IDA uptake was common to DNR and ADR, and that the binding site of IDA on the carrier was the same as that for DNR, but not that for ADR, while in MNCs the carrier system consisted of, at least in part, a carrier for DNR uptake and one for ADR uptake, and the binding site of IDA was identical to that for DNR in the former, but different from that for ADR in the latter. It appeared that the uptake of IDA was greater than those of pirarubicin, DNR and ADR in both HL60 cells and MNCs, and that IDA was incorporated into MNCs more efficiently than into HL60 cells because of the higher uptake efficacy of the carrier(s).

The characteristics of pirarubicin transport have been investigated in polymorphonuclear leukocytes isolated from rats. The uptake of pirarubicin by leukocytes was time-, temperature- and concentration-dependent with the maximum velocity (Vmax) of 4.84 nmol/5 x 10(6) cells/min and the Michaelis constant (Km) of 13.4 microM. The uptake depended on the extracellular pH, indicating that the molecular form of pirarubicin is more permeable than its ionic form and/or that the transporter of pirarubicin has optimal pH range. When the intracellular space was changed by increasing the medium osmolarity with sucrose, the uptake was altered by osmolarity changes and it appeared that about 27% of the drug was bound to the membrane surface. The initial uptake was inhibited by the metabolic inhibitors rotenone, 2,4-dinitrophenol and sodium cyanide. Pirarubicin accumulation in the intracellular glucose-depleted cells diminished significantly compared with that in normal cells. The efflux of pirarubicin from leukocytes was also temperature-dependent and inhibited by a metabolic inhibitor. These results indicate that a specific mechanism is concerned in the transport of pirarubicin in polymorphonuclear leukocytes.

We investigated the distribution and stability of pirarubicin in human blood obtained from 12 healthy volunteers. The distribution of pirarubicin into blood cells showed marked temperature- and concentration-dependencies and the Arrhenius plot for pirarubicin uptake in blood was biphasic. Therefore, pirarubicin appears to be taken up into blood cells by a carrier-mediated system. Pirarubicin was mainly enzymatically metabolized to pirarubicinol in blood cells, but pirarubicin was not metabolized into doxorubicin in either blood or plasma. On the other hand, in plasma, pirarubicin was degraded to unknown inactive compounds instead of pirarubicinol. It is therefore suggested that blood cells serve to protect against the degradation of pirarubicin into inactive compounds in blood. Accordingly, when the monitoring of pirarubicin and its active metabolites is carried out in patients, both blood and plasma must be frozen immediately after blood collection.

The distribution of zonisamide, a new antiepileptic drug, in erythrocytes and in brain was studied to clarify the factors influencing its distribution in epileptic patients. In both humans and rats, zonisamide was concentrated significantly in erythrocytes in a saturable manner. When the effective concentration of zonisamide in serum was compared with that in blood in nine refractory epileptic patients taking zonisamide chronically, the variation in effective serum concentration was significantly larger than that in blood concentration. In rats, the distribution in the brain also showed saturability. These results suggest that differences in saturable binding to various tissues may contribute to the wide variation that occurs in the effective serum concentration of zonisamide in epileptic patients and that monitoring of the blood concentration of zonisamide may provide useful information for treatment with this drug.

The pharmacokinetics of pirarubicin and its active metabolite, doxorubicin, were studied after intravenous administration of pirarubicin (25-45 mg/m2) to ten pediatric patients. The concentration-time curves of pirarubicin in both blood and plasma showed representative biphasic patterns. Pirarubicin concentrations decreased rapidly from 0.5 to 2 h after administration and then decreased slowly until 24 h in all subjects. High concentrations of the metabolite, doxorubicin, were detected at 0.5 h after administration of pirarubicin which decreased gradually until 24 h. The area under the concentration-time curve from 0 to 24 h (AUC0-24) of pirarubicin and doxorubicin in blood were 3-4 times higher than those in plasma, suggesting that these drugs had a high affinity for blood cells. The AUC0-24 ratio of doxorubicin to pirarubicin in plasma was calculated to be 0.441. It might be indicated that not only pirarubicin but also doxorubicin are responsible for the therapeutic efficacy and the incidence of toxicity of pirarubicin. The pharmacokinetics of pirarubicin in pediatric patients was fundamentally similar to that of adults, but it was recognized that considerable interindividual variation in the disposition of pirarubicin and doxorubicin exists.