Isolation and characterization of an anti-complementary protein-bound polysaccharide from the stem barks of Eucommia ulmoides

EWDS-1, a homogeneous protein-bound polysaccharide, was isolated as an anti-complementary agent from the stem barks of Eucommia ulmoides. EWDS-1 was identified as a branched proteoglycan with average molecular weight about 2,000,000 Da, composed of Gal, Glc and Ara in the ratio of 2.1:1.0:0.9, along with trace of Rha, Xyl, Man, as well as 3.95% of protein. The linkages of the residues of EWDS-1 were deduced by methylation analysis and NMR technique. Bioassay showed that EWDS-1 inhibited complement activation on both the classic and alternative pathways with CH(50) and AP(50) values of 203+/-20 microg/ml and 45+/-8 microg/ml, respectively. Preliminary mechanism studies by using complement component depleted-sera indicated that EWDS-1 inhibits activation of complement system by interacting with C1q, C1r, C1s, C2, C3, C4, C5 and C9. The results suggested that EWDS-1 could be of promising benefits in treatment of the complement associated diseases.     

Stability of spironolactone in rat plasma: strict temperature control of blood and plasma samples is required in rat pharmacokinetic studies

The stability of spironolactone (SPN) in rat plasma was studied and its degradation was found to be an apparent first-order reaction. The apparent first-order rate constants (k(obs)) at 37, 23.5 and 0 degrees C were 3.543+/-0.261 (h-1, mean+/-S.D., n=3), 6.278+/-0.045 (x10(-1) h-1), and 7.336+/-0.843 (x10(-2) h-1), respectively. The half-lives were 0.20 h, 1.10 h, and 9.53 h. The degradation rate of SPN in rat plasma was markedly decreased when NaF, an esterase inhibitor, was added to the plasma, and the degradation was catalyzed by esterase in the plasma. These results indicated that not only plasma but also blood and serum samples in rat pharmacokinetic studies should be cooled to 0 degrees C, the temperature maintained, and treated as soon as possible. In pharmacokinetic studies reported previously, the temperature control of plasma, blood, and serum samples was not described. The pharmacokinetic study in rats after intravenous administration of SPN at 20 mg/kg was performed with strict temperature control of plasma and blood samples. The AUC, MRT, CL and Vd(ss) values (mean+/-S.E. of 4 rats) for SPN were 4100.8+/-212.9 ng h/ml, 0.29+/-0.01 h, 4915.7+/-248.0 ml/h/kg, and 1435.4+/-48.4 ml/kg, respectively. The AUC value was much larger than that previously reported. The AUC, MRT, Cmax and Tmax values (mean+/-S.E. of 4 rats) of canrenone, an active metabolite of SPN, after the administration of SPN were 4196.1+/-787.5 ng h/ml, 1.99+/-0.13 h, 1546.3+/-436.4 ng/ml and 1.0+/-0.0 h, respectively. This AUC value was almost identical to the value previously reported.     

Occupational and dietary exposures of humans to cyanide poisoning from large-scale cassava processing and ingestion of cassava foods.

The biochemical and toxicological effects of occupational and dietary exposure of humans to cyanide poisoning from large-scale cassava processing and ingestion of cassava foods were investigated using spectrophotometric and enzymatic methods. Analysis of urinary and serum thiocyanate (cyanide metabolite) from workers in cassava processing industries, who were 'frequent' [those who eat cassava food(s) at least once a day] and 'infrequent' [those who eat cassava food(s) only occasionally] consumers of cassava-based diets, was carried out with the aid of questionnaries. The mean urinary thiocyanate level of the cassava processors (mean+/-S.D.; 153.50+/-25.21 micromo1/l) was 2.2 and 2.6 times higher than that of frequent (70.1+/-21.8 micromo1/l) and infrequent (mean+/-S.D.; 59.30+/-17.0 micromo1/l) cassava consumers, respectively. The mean serum thiocyanate levels rose to 126.73+/-12.4 micromo1/l for the former and 68.4+/-18.3 and 54.7+/-13.2 micromo1/l, respectively, for the latter. An increase in plasma activity by 10% above normal of aspartate aminotransferase (AST) was observed in 40% of the cassava processors, whereas it was within normal range in all consumers. The activities of alanine aminotransferase (ALT) and alkaline phosphatase (ALK.PHOS) were within the normal value in all cases studied. The blood glucose level of 50% of the cassava processors was 100 mg/ml or above while that of the consumers was in the range of 68-85 mg/100 ml. The total protein, serum albumin and creatinine levels were in the range for normal values for the processors and consumers. The health implications of these findings are discussed.     

Evaluation of brain-targeting for the nasal delivery of estradiol by the microdialysis method

The uptake of estradiol into the cerebrospinal fluid (CSF) after intranasal and intravenous administration in rats was investigated to study whether direct nose-CSF transport of estradiol exits or not. Animals received 0.48 mg kg(-1) estradiol randomly methylated beta-cyclodextrin (RAMEB) inclusion complex intranasally and intravenously. Following nasal delivery, estradiol reached a C(max) value (mean+/-S.D.) in plasma (26.70+/-11.37 ng ml(-1)) and CSF (54.76+/-32.84 ng ml(-1)) after 20 min in each case, while after intravenous infusion, estradiol reached a C(max) value in plasma (170.08+/-64.67 ng ml(-1)) and CSF (26.48+/-11.34 ng ml(-1)) at 5 min and 60 min, respectively. The AUC(CSF)/AUC(plasma) ratio (1.60+/-0.67) after intranasal delivery differed significantly from the ratio (0.61+/-0.16) observed after intravenous infusion (P<0.05). All these results indicate that estradiol is transported into CSF via olfactory neurons, and, hence, there is a direct transport route from the nasal cavity into the CSF for estradiol.     

The determination of glycyrrhizic acid in Glycyrrhiza uralensis Fisch. ex DC. (Zhi Gan Cao) root and the dried aqueous extract by LC-DAD

A rapid, sensitive and specific reversed phase high-performance liquid chromatographic (LC) method with photodiode array detection (DAD) has been developed for the determination of glycyrrhizic acid in both the raw herb and a commercially prepared dried aqueous extract of Glycyrrhiza uralensis Fisch. ex DC. root (Zhi Gan Cao, liquorice). It was determined that extracting the raw herb in aqueous methanol (50:50 v/v) by sonication for 2 x 30 min was the most efficient sample preparation. Baseline resolution of the glycyrrhizic acid peak was achieved on a Varian Polaris RP C18-A (250 mm x 4.6 mm, 5 microm packing) column using an isocratic mobile phase consisting of 0. v aqueous phosphoric acid and acetonitrile in the ratio 60:40 v/v. Chromatograms were monitored between 200 and 400 nm for peak purity assessments, with quantitation performed at 254 nm. Glycyrrhizic acid calibration curves in the concentration range of 14-558 microg/ml were prepared on the day of analysis. Curve fitting was by the least-squares method, with correlation coefficients of >0.9998 obtained each time. The average recovery at three spike levels (50, 100, 200%) was of 95.91+/-1.05% and 98.36+/-3.45% (+/-S.D., n=7) for the spiked raw herb and dried aqueous extract respectively. The limit of detection and limit of quantitation was 0.52 and 1.72 mg/g respectively for the raw herb, and 0.75 and 2.51 mg/g respectively for the dried aqueous extract. Identity confirmation of the chromatographic peak was achieved by (-) electrospray ionisation tandem mass spectrometry. The concentration of glycyrrhizic acid in the root and dried aqueous extract was found to be 31.1+/-0.2 and 40.4+/-0.3mg/g (+/-S.D., n=7) respectively.     

Alpha-glucosidase inhibitory activity and lipid-lowering mechanisms of Moringa oleifera leaf extract

OBJECTIVES AND MATERIALS AND METHODS: Medicinal plants constitute an important source of potential therapeutic agents for diabetes and hyperlipidemia. The purpose of present study was to investigate the effect of leaf extract of Moringa oleifera on inhibition of alpha-glucosidase and pancreatic alpha-amylase related to diabetes mellitus. Moreover, the study was also determined in vitro bile acid binding capacity as well as inhibition of cholesterol micellization, pancreatic lipase, and cholesterol esterase activity. RESULTS: The phytochemical analysis indicated that total phenolic, flavonoid, and condensed tannin contents in the extract were 45.21 +/- 0.96 mg gallic acid equivalents/g extract, 15.39 +/- 0.58 mg catechin equivalents/g extract, and 4.90 +/- 0.20 catechin equivalents/g extract, respectively. In addition, the extract contained a specific inhibitor of intestinal sucrase than intestinal maltase with IC50 value of 0.78 +/- 0.21 mg/ml, whereas it slightly inhibited pancreatic alpha-amylase and pancreatic cholesterol esterase. However, the extract had no inhibitory activity against pancreatic lipase. Furthermore, taurodeoxycholic acid, taurodeoxycholic acid, and glycodeoxycholic acid were bound to the extract (1 mg/ml) with a degree of 26.90 +/- 0.37%, 21.78 +/- 0.68%, and 22.59 +/- 1.02%, respectively. Finally, the extract (10 mg/ml) markedly inhibited the formation of cholesterol micelle about 40.22 +/- 2.64%. CONCLUSION: Our results indicated that the leaf extract of Moringa oleifera may be used for the control of blood glucose and lipid concentration and prevention of hyperglycemia and hyperlipidemia.     

Pharmacokinetics of subcutaneously administered etanercept in subjects with psoriasis

AIMS: To present the results of the pharmacokinetic analysis of the concentration-time profiles of etanercept, a soluble receptor tumour necrosis factor (TNF) antagonist, in more than 1300 subjects with psoriasis. METHODS: Pharmacokinetic samples were collected in one phase-2 and two phase-3 placebo-controlled, randomized clinical trials. Study 1 evaluated a 25-mg twice weekly (BIW) etanercept dosing regimen administered by subcutaneous (s.c.) injection for 24 weeks. Study 2 evaluated 25-mg BIW and 50-mg BIW s.c. doses for 12 weeks. Study 3 evaluated 25 mg once weekly (QW), 25 mg BIW and 50 mg BIW s.c. doses for 24 weeks. RESULTS: The mean +/- SD steady-state predose serum concentrations of etanercept for the 25-mg BIW arm at 12 weeks in study 1 were 1590 +/- 885 ng ml(-1). In study 2, mean +/- SD etanercept steady-state concentrations at 12 weeks were 1900 +/- 1110 ng ml(-1) in the 25-mg BIW group and 3830 +/- 1870 ng ml(-1) in the 50-mg BIW group. The mean +/- SD steady-state predose serum concentrations of etanercept at 12 weeks in study 3 were 768 +/- 475 ng ml(-1) for the 25-mg QW regimen, 1990 +/- 1030 ng ml(-1) for the 25-mg BIW regimen and 4020 +/- 2100 ng ml(-1) for the 50-mg BIW regimen. CONCLUSIONS: Pharmacokinetic results were highly consistent across clinical trials. The concentration-time profiles displayed dose proportionality. Etanercept concentrations in subjects with psoriasis are similar to the concentrations in subjects with rheumatoid arthritis.     

Pharmacokinetic/pharmacodynamic modelling of the anti-hyperalgesic and anti-nociceptive effect of adenosine A1 receptor partial agonists in neuropathic pain

The objective of this investigation was to characterise the pharmacokinetic-pharmacodynamic correlation of adenosine A1 receptor partial agonists in the chronic constriction injury model of neuropathic pain. Following intravenous administration of 8-methylamino-N6-cyclopentyl-adenosine (MCPA; 10 mg/kg) and 2'deoxyribose-N6-cyclopentyl-adenosine (2'dCPA; 20 mg/kg), the time course of the effect on the mechanical paw pressure threshold was determined in conjunction with plasma concentrations. Population pharmacokinetic/pharmacodynamic analysis was applied to derive individual concentration-effect relationships. A composite model consisting of an E(max) model for the anti-hyperalgesic effect in combination with a linear model for the anti-nociceptive effect accurately described the concentration-effect relationship. For both compounds, a full anti-hyperalgesic effect was observed. The values of the EC50 for the anti-hyperalgesic effect were (mean+/-S.D.): 3170+/-1460 and 2660+/-1200 ng/ml for MCPA and 2'dCPA versus 178+/-51 ng/ml for the reference full agonist 5'deoxyribose-N6-cyclopentyl-adenosine (5'dCPA). The values of the slope for the anti-nociceptive effect were 1.9+/-0.30 and 1.2+/-0.20 g.microl/ng, respectively, versus 55+/-8 g microl/ng for 5'dCPA. Adenosine A1 receptor partial agonists behave as full agonists with regard to the anti-hyperalgesic effect in neuropathic pain, but the anti-nociceptive effect is diminished.     

Role of human liver cytochrome P4503A in the metabolism of etoricoxib, a novel cyclooxygenase-2 selective inhibitor.

Etoricoxib, a potent and selective cyclooxygenase-2 inhibitor, was shown to be metabolized via 6'-methylhydroxylation (M2 formation) when incubated with NADPH-fortified human liver microsomes. In agreement with in vivo data, 1'-N'-oxidation was a relatively minor pathway. Over the etoricoxib concentration range studied (1-1300 microM), the rate of hydroxylation conformed to saturable Michaelis-Menten kinetics (apparent K(m) = 186 +/- 84.3 microM; V(max) = 0.76 +/- 0.45 nmol/min/mg of protein; mean +/- S.D., n = 3 livers) and yielded a V(max)/K(m) ratio of 2.4 to 7.3 microl/min/mg. This in vitro V(max)/K(m) ratio was scaled, with respect to yield of liver microsomal protein and liver weight, to obtain estimates of M2 formation clearance (3.1-9.7 ml/min/kg of b.wt.) that agreed favorably with in vivo results (8.3 ml/min/kg of b.wt.) following i.v. administration of [(14)C]etoricoxib to healthy male subjects. Cytochrome P450 (P450) reaction phenotyping studies-using P450 form selective chemical inhibitors, immunoinhibitory antibodies, recombinant P450s, and correlation analysis with microsomes prepared from a bank of human livers-revealed that the 6'-methyl hydroxylation of etoricoxib was catalyzed largely (approximately 60%) by member(s) of the CYP3A subfamily. By comparison, CYP2C9 (approximately 10%), CYP2D6 (approximately 10%), CYP1A2 (approximately 10%), and possibly CYP2C19 played an ancillary role. Moreover, etoricoxib (0.1-100 microM) was found to be a relatively weak inhibitor (IC(50) > 100 microM) of multiple P450s (CYP1A2, CYP2D6, CYP3A, CYP2E1, CYP2C9, and CYP2C19) in human liver microsomes.     

Double-blind study of dilevalol and captopril, both in combination with hydrochlorothiazide, in patients with moderate to severe hypertension.

Sixty-one patients (41 men, 20 women) aged 29-73 years, with moderate to severe hypertension, were enrolled in a multicentre study to compare the efficacy, safety, and tolerability of dilevalol (D) and captopril (C). At the end of the baseline period, supine diastolic blood pressure (SuDBP) was 105-140 mm Hg on hydrochlorothiazide (HCTZ) 25 mg once daily and placebo t.i.d. Patients were randomly assigned to D + HCTZ (n = 29) or C + HCTZ (n = 32) and entered phase II titration of D (100-800 mg b.i.d.) or C (12.5 mg b.i.d. to 50 mg t.i.d.). If SuDBP was greater than 99 mm Hg, hydralazine was added (25 mg once daily to 50 mg b.i.d.). If SuDBP was less than or equal to 99 mm Hg, patients entered phase III, a 3-month maintenance period. Demographic profiles were not significantly different between the two groups. Baseline supine BP (mean +/- SEM) was similar in the two groups (D + HCTZ: 182 +/- 3/112 +/- 1; C + HCTZ: 179 +/- 4/113 +/- 1 mm Hg), as was baseline standing BP (D + HCTZ: 175 +/- 3/114 +/- 2; C +/- HCTZ: 173 +/- 4/113 +/- 1 mm Hg). At the end of phase II, there were no significant differences between treatments with respect to the changes in BP from baseline.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of brain-targeting for the nasal delivery of ergoloid mesylate by the microdialysis method in rats.

The aim of this study was to quantify the nasal delivery of ergoloid mesylate (EM) to the brain by comparing cerebrospinal fluid (CSF) and plasma EM levels after nasal administration at a dose of 4 mg/kg with those after intravenous administration. Following nasal delivery, EM reached a Cmax value (mean+/-SD) in plasma of 348.41+/-19.47 ng/ml and in CSF of 87.35+/-6.37 ng/ml after 107 and 20 min, respectively, while after intravenous injection, EM reached a Cmax value (mean+/-S.D.) in CSF of 54.81+/-4.92 ng/ml at 60 min and the Cmax in plasma was 1255.51+/-133.59 ng/ml. The AUC(CSF)/AUC plasma ratio (0.48+/-0.05) after intranasal delivery differed greatly from the ratio (0.14+/-0.04) observed after intravenous injection (P<0.05). The further analyzed data demonstrated a statistically significant distribution advantage of EM to the brain via the nasal route, and further suggesting that nasal administration can be a promising alternative for EM that undergoes first-pass metabolism following oral administration.     

Fluoxetine augmentation in citalopram non-responders: pharmacokinetic and clinical consequences

In an open trial 11 in-patients with a major depressive episode (ICD-10), extensive metabolizers of mephenytoin (CYP2C19) and dextromethorphan (CYP2D6) and who were non-responders to a 3-wk pretreatment with 40 mg/d citalopram (Cit), were co-medicated for 7 wk (days 0-49) with fluoxetine (Fluox) (10 mg/d). Plasma concentrations of S-Cit and R-Cit significantly increased from day 0 (means+/-S.D.: 28+/-9 and 47+/-11 &mgr;g/l, respectively) to day 49 (58+/-12 and 72+/-21 &mgr;g/l, respectively) (p & 0.01 for each comparison), and the S-Cit/R-Cit ratio increased from 0.61+/-0.16 to 0.82+/-0.12 (p & 0.01). Therefore, Fluox increases the pharmacologically more active S-Cit (in comparison with R-Cit) with some stereoselectivity, most probably by inhibition of CYP2D6 and CYP3A4. Eight of the 11 patients showed clinical improvement (reduction > 50% of the MADRS score) and the combined treatment was generally well tolerated.     

Eumelanin is a major determinant for 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) incorporation into hair of mice

Mice with different hair pigmentation were studied to evaluate the role of melanin in the incorporation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) into hair. Mice C57BL/6J-c2j/+ (white), C57BL/6J-Ay (yellow), C57L/J (grey), C57BR/cdJ (brown) and C57BL/6J (black) were dosed with PhIP: 7-9 days old (total amount: 0.006 or 0.58 mg/kg b.wt., for 4 days) and adults (total amount 50 mg/kg b.wt. during 8 weeks). Hair was collected either 30 days after the last PhIP administration (new-born mice) or 8 weeks after the first administration (adult mice). PhIP was incorporated into black hair to a greater extent than into brown, grey, yellow and non-pigmented hair. The concentration of PhIP in the hair of new-born mice exposed to 0.58 mg PhIP/kg b.wt. were (mean+/-S.D.): 328+/-135 (black), 134+/-41 (brown), 9.1+/-1.2 (yellow) and 5.2+/-1.4 (white) ng/g hair. The PhIP concentrations in the hair of adult mice exposed to 50 mg/kg b.wt. were: 4750+/-1449 (black), 810+/-235 (brown), 541+/-119 (grey), 35.5+/-4.6 (yellow) and 21.6+/-8.8 (white) ng/g, and the eumelanin hair concentration in the same animals decreased in a similar pattern. A linear relationship (r2= 1.00, P<0.0001) between the relative PhIP incorporation and the eumelanin concentration in hair was found.     

Pharmacokinetics and metabolism of the reactive oxygen scavenger alpha-phenyl-N-tert-butylnitrone in the male Sprague-Dawley rat.

The pharmacokinetics of the spin-trap alpha-phenyl-N-tert-butylnitrone (PBN) was investigated in male Sprague-Dawley rats. Plasma concentrations after i.v. administration (10 mg/kg) declined monoexponentially with a terminal half-life of 2.01 +/- 0.35 h and total plasma clearance (CL(p)) and volume of distribution at steady state (Vd(ss)) averaged 12.37 +/- 3.82 ml/min/kg and 1.74 +/- 0.5 l/kg, respectively. The observed CL(p) was in close agreement with the blood clearance (CL(b)) value (11.5 ml/min/kg) predicted from in vitro liver microsomal incubations suggesting that PBN CL(p) in rats is predominantly due to hepatic metabolism. Peak plasma concentration (C(max)) following p.o. (20 mg/kg) and s.c. (30 mg/kg) PBN administration was 7.35 +/- 1.92 and 3.56 +/- 0.66 microg/ml, whereas the area under the concentration-time curve from 0 to infinity was 23.89 +/- 5.84 and 15.96 +/- 3.10 microg-h/ml, respectively. The mean oral bioavailability of PBN was 85.63 +/- 20.93%. Biotransformation studies indicated the P450 2C11-catalyzed hydroxylation of PBN to M1. Potential sites of hydroxylation included the benzylic carbon resulting in phenyl-N-tert-butylhydroxamic acid or the phenyl ring that would afford alpha-hydroxyphenyl-N-tert-butylnitrone (HOPBN). The structure of M1 was established as alpha-4-Hydroxyphenyl-N-tert-butylnitrone (4-HOPBN) on the basis of: 1) obvious LC R(t) differences between M1 and the authentic hydroxamate standard, 2) P450 catalyzed hydroxylation of [(2)H]PBN that contained a deuterium instead of a hydrogen atom on its benzylic position and which afforded [(2)H]M1, and 3) comparison of the liquid chromatography-tandem mass spectrometry properties with a synthetic 4-HOPBN standard. We speculate that 4-HOPBN is an "active" PBN metabolite that provides an additive effect to the pharmacological action of PBN in vivo.     

Effect of CYP2D6 genotypes on the metabolism of haloperidol in a Japanese psychiatric population.

We investigated the effect of CYP2D6 genotypes on plasma levels of haloperidol (HAL) and reduced haloperidol (RHAL) in 88 Japanese schizophrenic inpatients being treated with HAL. Some subjects carrying CYP2D6*5 allele (CYP2D6*1/CYP2D6*5, CYP2D6*5/CYP2D6*10) showed extremely high concentrations of both HAL and RHAL, and the groups with CYP2D6*5 allele seemed to have higher plasma concentrations of HAL (1.14+/-0.69 ng/ml/mg) and RHAL (1.10+/-1.05 ng/ml/mg) than the other groups. Among those without CYP2D6*5 allele, there were no significant differences in plasma concentrations of HAL and RHAL between those without CYP2D6*10 allele (HAL=0.68+/-0.31 ng/ml/mg, RHAL=0.28+/-0.37 ng/ml/mg), those with one CYP2D6*10 (HAL=0.70+/-0.23 ng/ml/mg, RHAL=0.31+/-0.16 ng/ml/mg) and those with two CYP2D6*10 alleles (HAL=0.69+/-0.14 ng/ml/mg, RHAL=0.40+/-0.09 ng/ml/mg), although there was a tendency of higher plasma concentration of RHAL in those with two CYP2D6*10 alleles. At a lower daily dosage of HAL (<10 mg/day), the subjects with two or one CYP2D6*10 allele(s) showed significantly higher plasma concentrations of RHAL (0.43+/-0.23 ng/ml/mg, 0.34+/-0.16 ng/ml/mg) than those without CYP2D6*10 allele (0.18+/-0.16 ng/ml/mg). The results of this study indicate that CYP2D6*10 allele plays significant but modest role in HAL metabolism in Japanese; nevertheless, we should not lump CYP2D6*10 allele with CYP2D6*5 allele because these two mutated alleles seem to have different impacts in the metabolism of HAL.     

A study of the absorption and excretion of fosfomycin sodium in children

Fosfomycin sodium (FOM-Na, Forocyle-S) was administered at 25 mg/kg or 50 mg/kg to 15 children between the ages of 3 and 15 through intravenous injection or through 1 hour intravenous drip infusion, and concentrations in blood serum and excretion through urine were examined and a pharmacokinetic analysis was carried out using the one-compartment model. 1. Average concentrations in the blood serum after injections with 25 mg/kg and 50 mg/kg were 55.3 +/- 6.3 micrograms/ml and 118.8 +/- 31.1 micrograms/kg 30 minutes after injection, respectively, and their half-lives were 1.04 +/- 0.15 hours and 0.98 +/- 0.17 hours, respectively. Six hours after injection, the levels were 2.7 +/- 1.6 micrograms/kg and 6.2 +/- 5.5 micrograms/kg, respectively. With 1 hour intravenous drip infusion of 25 mg/kg and 50 mg/kg, average concentrations the blood serum were 34.2 +/- 14.9 micrograms/ml and 89.7 +/- 6.7 micrograms/ml, respectively, and their half-lives were 0.87 +/- 0.24 hour and 0.69 +/- 0.10 hour, respectively. Six hours after the administration, the levels were 2.7 +/- 1.8 micrograms/ml and 6.7 +/- 0.8 micrograms/ml. There was a clear dose response in the concentration levels in the blood in those given the drug at 25 mg/kg and 50 mg/kg in either method of administration. 2. Average levels in urine after injection of 25 mg/kg and 50 mg/kg were 5,778 +/- 2,257 micrograms/ml and 6,268 +/- 3,329 micrograms/ml 0-2 hours after administration, respectively, and average levels at 4-6 hours were 701 +/- 765 micrograms/ml and 1,588 +/- 1,324 micrograms/ml, respectively. Average excretion, rates into the urine were 72.8 +/- 11.0 and 73.9 +/- 11.1%, respectively. In case of 1 hour drips infusion of 25 mg/kg and 50 mg/kg, average concentrations in the urine 0-2 hours after administration were 3,570 +/- 1,540 micrograms/ml and 11,800 micrograms/ml, respectively, and averages for 4-6 hours were 211 +/- 124 micrograms/ml and 1,300 micrograms/ml. Average rates of excretion into the urine for the first group was 57.9 +/- 16.3% and the second group was 78.4%. Clear dose response was observed in changes of drug concentration levels in the urine with 25 mg/kg and 50 mg/kg doses through either administration method, and in terms of excretion into the urine, no noticeable differences were observed between the different amounts administered or different administration methods.(ABSTRACT TRUNCATED AT 400 WORDS)     

Pharmacokinetics/pharmacodynamics of acetaminophen analgesia in Japanese patients with chronic pain

Acetaminophen (APAP) is a popular analgesic. In the present study, we characterized the pharmacokinetics and pharmacodynamics of APAP in the Japanese. Five healthy volunteers were administered 1000 mg of APAP orally. Five patients with chronic pain were administered the optimal oral dose of APAP ranging from 600 to 1000 mg to allow for an adequate analgesic effect. Plasma APAP and APAP metabolite concentrations were measured in the volunteers, plasma APAP concentrations and pain scores using a visual analog scale were measured in the patients with chronic pain. Patient data were fitted to a first-order absorption one-compartment model with delayed effects accounted for by an effect compartment. A sigmoid Emax model was used as the pharmacodynamic model. Acetaminophen-cysteine metabolites, which are conjugates of the toxic metabolite N-acetyl-p-benzoquinone-imine, were detected in the plasma at levels lower than 0.2 microg/ml, but no side effects were observed. The pharmacokinetic and pharmacodynamic parameter (mean+/-S.D.) estimates were as follows: clearance, 18.7+/-4.7 l/h; distribution volume, 30.9+/-6.8 l; absorption rate constant, 2.4+/-1.3 h(-1); rate constant for the elimination of APAP from the effect compartment, 1.3+/-0.5 h(-1); maximum pain relief score, 4.6+/-2.2 units; effect compartment concentration at 50% maximum, 2.0+/-1.2 microg/ml; and sigmoid factor, 1.3+/-0.7. These results suggest that these parameters can be used to determine an effective APAP dosage regimen for Japanese patients with chronic pain.     

Glucuronidation of DRF-6574, hydroxy metabolite of DRF-4367 (a novel COX-2 inhibitor) by pooled human liver, intestinal microsomes and recombinant human UDP-glucuronosyltransferases (UGT): role of UGT1A1, 1A3 and 1A8.

DRF-4367 is a novel COX-2 inhibitor, which showed good efficacy in several animal models of inflammation. In a comparative in vitro metabolism in various liver microsomes, DRF-4367 forms a hydroxy metabolite (DRF-6574) mediated by CYP2D6 and 2C19 isoenzymes. DRF-6574 readily undergoes Phase-II metabolism and forms glucuronide and sulfate conjugates both in vitro and in vivo. The objective of the present study was two folds: to study the glucuronidation of DRF-6574 in human liver and intestinal microsomes and to identify the recombinant human liver and intestinal UDP-glucuronosyltransferase (UGT) enzymes responsible for glucuronidation of DRF-6574. Of twelve recombinant UGTs tested, two hepatic UGTs viz., UGT1A1 and 1A3 and an extra hepatic UGT i.e., UGT1A8 showed the catalytic activity. The enzyme kinetics in pooled human liver, intestinal and recombinant UGT microsomes showed a typical Michaelis-Menten plot. The apparent Km and Vmax value for DRF-6574 was found to be 116 +/- 24 microM and 2.07 +/- 0.12 microg/min/mg protein and 142 +/- 17 microM and 3.83 +/- 0.15 microg/min/mg protein in pooled human liver and intestinal microsomes, respectively. The intrinsic clearance (Vmax/Km) value for DRF-6574 was estimated to be 0.043 and 0.065 ml/min/mg protein, respectively in pooled human liver and intestinal microsomes. Moreover we have determined the Km and Vmax and intrinsic clearance values for specific UGTs viz., UGT 1A1, 1A3 and 1A8. The apparent Km and Vmax values are 23 +/- 7.2 microM, 3.44 +/- 0.17 microg/min/mg protein for UGT1A1, 60 +/- 7.9 microM, 3.67 +/- 0.11 microg/min/mg protein for UGT1A3, 96 +/- 8.0 microM, 2.95 +/- 0.06 microg/min/mg protein for UGT1A8. The intrinsic clearance values (Vmax/Km) estimated were 0.367, 0.148, 0.074 ml/min/mg protein for UGT1A1, 1A3 and 1A8, respectively. The intrinsic clearance value in UGT1A8 was very close to that in human intestinal and liver microsomes. The formation of DRF-6574 glucuronide by human liver, intestinal and UGT1A1, 1A3 and 1A8 microsomes was effectively inhibited by phenylbutazone.     

The role of CYP2C19 in amitriptyline N-demethylation in Chinese subjects

OBJECTIVE: To determine the role of cytochrome P(450) (CYP)2C19 in N-demethylation of amitriptyline (AT) in healthy Chinese subjects.METHODS: One hundred and one subjects were genotyped for CYP2C19 using polymerase chain reaction-restriction fragment length polymorphism analysis. Twelve unrelated adult men (19.7+/-0.6 years, 61.8+/-3.8 kg) were chosen and orally given a single dose of 50 mg AT, and the blood samples were drawn from a forearm vein at 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12, 24, 48, 72, and 96 h after AT administration. Plasma concentrations of AT and nortriptyline (NT) were determined using high-performance liquid chromatography with an ultraviolet detector.RESULTS: The mean area under the plasma concentration-time curve (AUC(AT)) of CYP2C19 poor metabolizers (PMs, n=6) was significantly higher than that of CYP2C19 extensive metabolizers (EMs, n=6) (2207+/-501 ng/ml x h(-1) vs 1596+/-406 ng/ml x h(-1), P<0.05). In contrast, the mean AUC(NT(0-)(infinity)()) of PMs was significantly lower than that of EMs (294+/-70 ng/ml x h(-1) vs 684+/-130 ng/ml x h(-1), P<0.0001). Other pharmacokinetic parameters such as clearance, half-life, maximum plasma concentration, and time to peak plasma concentration showed no significant difference between PMs and EMs (0.41+/-0.12 l /h x kg(-1) vs 0.50+/-0.15 l /h x kg(-1), 25.0+/-6.2 h vs 24.1+/-4.4 h, 96+/-25 ng/ml vs 75+/-27 ng/ml, 4.0+/-1.4 h vs 3.7+/-1.5 h, respectively).CONCLUSION: The genetic defects of CYP2C19 have a significant effect on AT pharmacokinetics, and CYP2C19 plays an important role in N-demethylation of AT in vivo at a clinically therapeutic dose.     

Transfer of latamoxef into human burn blister fluid and its pharmacokinetic analysis

Latamoxef (LMOX) (50 mg/kg) was administrated intravenously to burned patients over 1 hour period. Burn blister fluid and serum were taken during 8 hours after injection, and concentrations of LMOX in burn blister fluid and serum were determined by bioassay using E. coli as a test organism. The serum concentrations of LMOX were 170.8 +/- 30.6 micrograms/ml at 30 minutes, 227.0 +/- 19.8 micrograms/ml at 1 hour, 90.3 +/- 21.4 micrograms/ml at 2 hours, 52.9 +/- 14.6 micrograms/ml at 3 hours, 38.7 +/- 13.3 micrograms/ml at 4 hours, 25.1 +/- 8.1 micrograms/ml at 5 hours, 20.5 +/- 8.1 micrograms/ml at 6 hours, 13.0 +/- 5.5 micrograms/ml (mean +/- S.D., n = 5) at 8 hours after the injection. The LMOX concentrations in burn blister fluid were 36.9 +/- 32.8 micrograms/ml at 30 minutes, 77.5 +/- 42.2 micrograms/ml at 1 hour, 85.4 +/- 19.6 micrograms/ml at 2 hours, 76.4 +/- 18.5 micrograms/ml at 3 hours, 63.5 +/- 17.8 micrograms/ml at 4 hours, 54.9 +/- 17.1 micrograms/ml at 5 hours, 34.8 +/- 10.3 micrograms/ml at 6 hours, 25.2 +/- 4.8 micrograms/ml (mean +/- S.D., n = 7) at 8 hours after the injection. The data obtained were analysed pharmacokinetically. The serum levels were analysed by two-compartment model, and the LMOX levels in burn blister fluid were analysed by the model, in which blister was considered as a small part of the peripheral compartment. In results, Tmax and Cmax of LMOX levels in burn blister fluid were calculated as 1.81 hours and 90.6 micrograms/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)