Concentration of temarotene (Ro 15-0778) and its metabolite Ro 14-6113 in plasma and skin of hairless rat

The aim of this preliminary report was to measure plasma and skin concentrations of Ro 15-0778 and its phenolic metabolite Ro 14-6113 in hairless rats receiving orally 10 mg/kg of Temarotene once daily during 10 days. Blood (2-3 ml) and skin (200-300 mg) samples were taken at different time points between 0.5 and 240 h after the last dose. We used a highly sensitive HPLC method for simultaneous determination of the two compounds with a quantification limit of 2 ng/ml in plasma and 10 ng/g in total skin (epidermis and dermis). After 10 h, plasma concentrations of Ro 14-6113 were 5-13 times higher than for Ro 15-0778. Ro 14-6113 concentrations in the skin were 4-10 times higher than for Ro 15-0778 within the initial 48 h. The concentrations of both compounds in the skin were higher than concentrations in plasma.

Use of solid state fermentation to produce Beauveria bassiana for the biological control of european corn borer

The production process of a new bioinsecticide against european corn borer is described. The entomopathogenic fungus, Beauveria bassiana, is cultivated by Solid State Fermentation (SSF). The culture support chosen, clay microgranules, humidified with optimal nutritive solution, is incubated in optimal conditions during 48 hours, then dried for 5 days. The bioinsecticide can be directly used after harvesting, without formulation. This process is original for several reasons : - The granulometry (500 microm) and the bulk density (0.6) of the microgranules are compatible with the mechanical standard application of pesticides on corn. - The bioinsecticide could be produced in a pilot reactor of 1600 1 capacity, on 0.5m-thick-layer.- The biomass bound to microgranules conserves its efficiency after storage for 12 months at 4 degrees C, unlike pure cells. - Like the chemical insecticides usually used, this bioproduct has a field efficiency of 80%. Moreover, the efficiency of the product persists during 3 weeks.

Solid state fermentation reactors: From lab scale to pilot plant

Relatively many workers in the world are studying different aspects in SSF processes but few are working on reactor design and scale-up. From about 10 years, we are developing reactors from lab scale to pilot plant, based on the same technology, reactor design and flowsheet to allow fermentation with a deep layer (up to 1 m in the pilot plant). These reactors have all a forced aeration and the possibility or not to agitate. Regulations of temperature and water content of the culture are monitored by a special device.

Use of chitin measurement to estimate fungal biomass in solid state fermentation

Twenty-two strains of twelve species of Deuteromycotina: Hyphomycetes were studied. Most of them had a variable glucosamine amount (standard deviation higher than 5%). However, if we consider that the amount of glucosamine is constant, the accuracy of the method remains satisfactory (10% instead of 5%, which is the accuracy of the chitin hydrolysis and colorimetric glucosamine measurement). So, by means of this measurement, the fungal growth kinetics could be followed on different solid media (vegetable material such as sugar beet pulp and sponge or mineral like clay granules) used. It is important to note that this method should not be used to compare different media without calibration.

Evaluation of Bayesian estimation in comparison to NONMEM for population pharmacokinetic data analysis: application to pefloxacin in intensive care unit patients

The pharmacokinetics of pefloxacin (PF) were investigated in a population of 74 intensive care unit patients receiving 400 mg bid as 1-hr infusion using (i) Bayesian estimation (BE) of individual patient parameters followed by multiple linear regression (MLR) analysis and (ii) NONMEM analysis. The data consisted of 3 to 9 PF plasma levels per patient measured over 1 to 3 dosage intervals (total 113) according to four different limited (suboptimal) sampling 3-point protocols. Twenty-nine covariates (including 15 comedications) were considered to explain the interpatient variability. Predicted PF CL for a patient with median covariates values was similar in both BE/MLR and NONMEM analysis (4.02 and 3.92 L/hr, respectively). Bilirubin level and age were identified as the major determinants of PF CL by both approaches with similar predicted magnitude of effects (about 40 and 30% decrease of median CL, respectively). Confounding effects were observed between creatinine clearance (26% decrease of PF CL in the BE/MLR model), simplified acute physiology score (a global score based on 14 biological and clinical variables) (18% decrease of median CL in the NONMEM model) and age (entered in both models) which were highly correlated in our data base. However, both models predicted similar PF CL for actual subpopulations by using actual covariate values. Finally, the NONMEM analysis allowed identification of an effect of weight on CL (decrease of CL for weight < 65 kg) whereas the BE/MLR analysis predicted an increase of CL in patients treated with phenobarbital. In conclusion, both approaches allowed identification of the major risk factors of PF pharmacokinetics in ICU patients. Their potential use at different stages of drug development is discussed.

Comparative in vivo and in vitro regional selectivity of central omega (benzodiazepine) site ligands in inhibiting [3H]flumazenil binding in the rat central nervous system

The in vivo selectivity for central omega (benzodiazepine) modulatory site subtypes of ligands from several chemical classes has been evaluated by measuring the displacement of the in vivo binding of [3H]flumazenil to several rat central nervous system structures differentially enriched in omega 1 and omega 2 sites. This labeling was prevented in a dose-related manner by the i.p. administration, 30 min before the radioligand, of several benzodiazepine derivatives, the cyclopyrrolone derivatives suriclone and zopiclone, the triazolopyridazine derivative CL 218,872 and the imidazopyridine derivative zolpidem. Most of the benzodiazepine derivatives studied displayed in vivo some selectivity for omega 2-enriched structures. In contrast, oxoquazepam and CL 218,872 were 2- to 3-fold more potent at preventing [3H]flumazenil binding in omega 1-enriched (cerebellum) than in omega 2-enriched structures. Maximal inhibitions by zolpidem of in vivo [3H]flumazenil binding [cerebellum (100%) > cerebral cortex (79%) > or = striatum (74%) > hippocampus (52%) > spinal cord (37%)] were related to the relative omega 1/omega 2 distribution ratio in each structure. These differences did not result from an uneven distribution of this compound in the central nervous system. Quantitative autoradiographic studies performed on 30 central nervous system regions showed a strong correlation between the in vitro and in vivo regional selectivity of zolpidem. For all the drugs studied there was a significant global correlation between their potency at inhibiting [3H]flumazenil binding in vitro and in vivo either in the cerebellum (P < .001) or in the spinal cord (P < .01) and between the in vitro and in vivo cerebellum/spinal cord selectivity. The differential in vivo selectivity of zolpidem may account for the reported hypnoselective profile of this imidazopyridine in the rodent.

Influence of food on the tyramine pressor effect during chronic moclobemide treatment of healthy volunteers

An open study was carried out to examine the effect of moclobemide, a new antidepressant reversible inhibitor of MAO-A, on the pressor response induced by oral tyramine added to meals of different lipid and protein composition, and to correlate the blood pressure increase in the tyramine test with that obtained during an exercise test. Eight healthy volunteers of both sexes participated in the study. A tyramine sensitivity and an exercise test were performed beforehand. Subjects were included if, under fasting condition, their systolic blood pressure (SBP) increased by more than 30 mmHg after administration of 400 or 600 mg tyramine. Exercise tests were performed to determine the grade of effort that corresponded to a rise in SBP of 30 mmHg. Subjects received moclobemide 600 mg/d. Starting on Day 7, each subject consumed a standardized meal (52 g lipids, 43 g proteins, 86 g carbohydrates) just before taking moclobemide. Tyramine was added to these meals in daily increasing doses of 50, 100, 150...mg until an increase in SBP > or = 30 mmHg was obtained. On moclobemide treatment, an average dose of 250 mg tyramine (range 150-400 mg) increased SBP by 36.6 mmHg. The time to reach peak SBP was longer (175 min) than in the fasting condition before the trial (40.6 min).(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of lymphatic flow variation by noninvasive method cases of lymphedema

The purpose of this study was to measure the variations of lymphatic flow. A noninvasive isotopic method was used to achieve a functional exploration of lymphatic circulation. Fifteen subjects were used in the study: 10 healthy subjects and 5 patients with lower extremity lymphedema. A first subcutaneous injection of technetium 99m rhenium sulfate (99mTc) was performed in the first interdigital space of both feet. The radioactivity was recorded in two places: the first one on the inguinal site by a gamma camera; the second, below the first, on the precordial site by a multichannel analyzer. With the two types of recording procedures, it was possible to obtain a curve that showed the amount of radioactivity in relation to time. In order to obtain a muscular activity fifty-five minutes after the injection, each subject or patient spent ten minutes on an ergometric bike. A second subcutaneous injection was performed one week later, but prior to the injection, the subject or patient took orally 1800 mg of heptaminol adenosine phosphate (HAP) per day for three days. The radioactivity recording was made under the same conditions as with the muscular activity. The statistical results of the experiment without treatment on the two types of recording show that in the healthy subjects the amount of radioactivity increased during muscular activity. Moreover, the treatment indicated higher radioactivity values, which remained at a higher level. However, the muscular activity performed by a patient was unable to increase the radioactivity. On the other hand, the drug gave radioactivity values that were higher than the previous values of the first curve.(ABSTRACT TRUNCATED AT 250 WORDS)

Glutamic acid decarboxylase (GAD) autoantibodies are additional predictive markers of type 1 (insulin-dependent) diabetes mellitus in high risk individuals

The prevalence of glutamic acid decarboxylase autoantibodies was determined with an immunotrapping enzyme activity assay in newly-diagnosed Type 1 (insulin-dependent) diabetic patients as well as in first-degree relatives using rat brain homogenate as a source of glutamate decarboxylase. Twenty-six out of 86 islet-cell cytoplasmic auto-antibody positive and one out of 24 islet cell autoantibody negative patients of recent onset, had autoantibodies to glutamate decarboxylase above the upper 99% confidence limit obtained from 89 control sera. Among 27 islet cell autoantibody positive relatives including 19 siblings and 8 parents, antibodies to glutamate decarboxylase were found in 8 of 9 (89%) relatives and 7 of 8 (87.5%) siblings with islet cell auto-antibody titres above 20 JDF units, in 1 of 19 (5.2%) relatives with islet cell autoantibody titres between 2 and 5 JDF units, in 2 of 263 (0.7%) siblings and 1 of 139 parents without islet cell autoantibodies. In first-degree relatives, high titre islet cell autoantibodies and autoantibodies to glutamate decarboxylase were tightly associated (X2 = 182, p = 0.0001). None of the relatives with low genetic risk (n = 64), i.e. HLA-different to the diabetic proband, was found to be antibody positive. Antibodies to glutamate decarboxylase were present only in those relatives sharing at least one haplotype with the diabetic proband, including two islet cell autoantibody negative but HLA-identical siblings. Autoantibodies to glutamate decarboxylase were present in 7 of 9 (77%) relatives who developed the disease, including one islet cell autoantibody negative sibling.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of nifedipine in plasma by a rapid capillary gas chromatographic method

A rapid, specific and reliable gas chromatographic assay procedure for Nifedipine in plasma has been developed. With a single-step solvent extraction, and electron capture detection, the method is sensitive to 0.5 ng/mL of plasma and the standard curve is linear from 0.5 to 500 ng/mL. Samples are protected from light to prevent formation of photodecomposition products. The method has been used to monitor drug concentrations in patients receiving therapeutic doses.

Intertrial reliability of work measurements recorded during concentric isokinetic knee extension and flexion in subjects with and without meniscal tears

Intertrial reliability of work measurements was studied in 19 men with a partial medial meniscal tear (ME group) and in 10 men with no history of knee injury (control group). Three maximal voluntary concentric contractions of the muscles involved in knee extension (KE) and knee flexion (KF) were performed on a dynamometer at 30 degrees and 180 degrees/s using a preloading protocol. The subjects moved their legs through an arc of 90 degrees, and the work produced in the constant-velocity phase between 70 and 20 degrees of KE was computed for each trial. In ME group subjects able to perform three consecutive contractions (n = 12-14), high intertrial intraclass correlation coefficients (ICCs) were found (ICCs = .86-.92), except for KE work measurements at 180 degrees/s (ICC = .67). In the control group subjects, high ICCs were obtained for KE work measurements (ICCs = .87 and .95), whereas the low ICCs obtained for KF work measurements (ICCs = .64 and .79) increased to .86 and .93 when the first trial was removed. In both groups, a significant increase was found over the trials for KF measurements at 180 degrees/s and KE measurements at 30 degrees/s, but work measurements were shown to peak at the second trial. The results of this study suggest that the work produced on the second trial reflects a subject's maximal capacity. [Durand A, Malouin F, Richards CL, Bravo G. Intertrial reliability of work measurements recorded during concentric isokinetic knee extension and flexion in subjects with and without meniscal tears.

Metabolism of digoxin, digoxigenin digitoxosides and digoxigenin in human hepatocytes and liver microsomes

In vitro metabolism of digoxin and its cleavage-related compounds was investigated using hepatocytes in primary culture and microsomal fractions both isolated from human livers. On these models, digoxin (DG3) and digoxigenin bisdigitoxoside (DG2) were not shown to be significantly metabolized in vitro in man. Therefore, it appeared that the stepwise cleavage of DG3 and DG2 sugars was not cytochrome P450 dependent. This enzymatic system probably plays a minor role in humans for this particular reaction. However, digoxigenin monodigitoxoside (DG1) and digoxigenin (DG0) which are known to be formed after intra-gastric hydrolysis of DG3, were extensively converted to polar compounds (mainly glucuronides). In addition, using human liver microsomes, a wide variability in UDP-glucuronyl transferase (UDPGT) activities responsible for DG1 glucuronidation was demonstrated. These results suggest that two main factors may contribute to the overall interindividual variability of digoxin biotransformation: 1), the individual intra-gastric pH which influences the sugar cleavage leading to DG1 and DG0; ii), a variability in the level of the hepatic UDPGT specific for digitalis compounds conjugation.

1H nuclear magnetic resonance and clinical studies of interaction of calcium antagonists and hypoglycemic sulfonylureas

The hypoglycemic effect of gliclazide is mainly due to its action on ATP stimulated K+ channels, but the calcium ionophoretic effect of this drug may also be involved in its physiological properties. Using 1H NMR we demonstrated the antiionophoretic effect of nifedipine and diltiazem. We attempted to verify whether this in vitro interaction also occurs in vivo. A clinical trial, was performed on patients treated concomitantly with gliclazide and nifedipine or diltiazem. Results showed that no in vivo interaction occurred. The discrepancy between in vivo and in vitro results may be explained by a too weak plasma concentration in the case of nifedipine and by a large plasma protein binding in the case of diltiazem.

The disposition and pharmacokinetics of alpidem, a new anxiolytic, in the rat

The autoradiographic distribution, disposition, biliary excretion, and pharmacokinetics of alpidem in Sprague-Dawley rats were evaluated after iv or oral administration. Following i.v. administration, autoradiography showed that radioactivity was preferentially localized in lipid-rich tissues including central nervous system structures. After a 3-mg.kg-1 i.v. or oral dose of [14C]alpidem, more than 80% of the radioactivity were excreted in the feces over a 6-day period. Biliary excretion of radioactivity in vigile rats, about 74% of the dose over a 7-hr period after either iv or oral administration, showed that alpidem was well absorbed. The absolute bioavailability (13%) data indicated a high first-pass effect. Plasma pharmacokinetic parameters of alpidem were as follows: Vd = 5 liter.kg-1, Cl = 2.2 liter.h-1.kg-1, and terminal t 1/2 beta = 1.2-1.7 hr. Three metabolites with a pharmacological activity similar to that of alpidem were detected in plasma. They were eliminated from the central compartment with half-lives comparable to that of the parent drug. Alpidem crossed the blood-brain barrier following either i.v. or oral administration, resulting in cerebral levels 2.5 to 4 times greater than the plasma levels. Alpidem was eliminated from the central nervous system according a biphasic process with a t 1/2 alpha comparable in plasma and brain. Alpidem represented 94 and 63% of cerebral radioactivity 5 min after i.v. and oral administration, respectively. Two out of the three active plasma metabolites were detected in the brain.

Insulin prevents adoptive cell transfer of diabetes in the autoimmune non-obese diabetic mouse

Early intensive insulin treatment is thought to improve subsequent Beta-cell function in Type 1 (insulin-dependent) diabetic patients. Prophylactic insulin administration also reduced diabetes incidence in diabetes-prone animals. To study the mechanisms by which these effects occur, we tested the ability of insulin therapy in the model of non-obese-diabetic mice, to prevent the penetration of committed T cells into the islets and subsequent Beta-cell destruction. Sublethally irradiated non-obese-diabetic males of 8 weeks of age were adoptively transferred with splenocytes from diabetic donors and treated with the maximum tolerable dosage of fast-acting insulin (0.5 U, twice daily) until 30 days after cell transfer. Diabetes incidence was compared to control animals injected with the same concentration of insulin diluent. After one month of treatment, the cumulative diabetes frequency was significantly less within the insulin-treated group (4 of 15, 26.6%) than in the control group (15 of 18, 83.3%; p less than 0.01). Pancreatic histological analysis of insulin-treated animals revealed a lower severity of insulitis and Beta-cell necrosis and a higher percentage of normal islets (46.6 +/- 10% vs 2.3 +/- 2%, p less than 0.01), including five (33%) mice with no lesions. Immunoperoxydase staining of pancreatic sections indicated similar insulin and ganglioside staining of Beta cells from insulin-treated mice and control animals. Insulin-treated mice had comparable pancreatic insulin content to normal mice. Flow cytometry analysis of spleen cell populations indicated that insulin increased the number of Thy1,2+ and Lyt-2+ T cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of nicardipine on pulmonary and systemic vascular reactivity to oxygen in patients with pulmonary hypertension secondary to chronic obstructive lung disease

We compared the acute effects of nicardipine and a placebo on the response of pulmonary and systemic circulation to different inspiratory fractional concentrations of O2 (FiO2) in 10 patients with pulmonary hypertension secondary to chronic obstructive lung disease. After catheterization of the pulmonary and femoral arteries, gas mixtures containing 15, 21, and 30% O2 were randomly administered for 20 min each during infusion of saline and then nicardipine (0.06 mg/kg/min). Plasma nicardipine level was maintained at 30 ng/ml. During nicardipine infusion, cardiac index (CI) was significantly higher (+20%, p less than 0.05) than during placebo infusion, with no change in mean pulmonary artery pressure (MPAP). Pulmonary resistances also decreased significantly (-20%) during nicardipine. No change in arterial or mixed venous O2 contents was noted. Mean arterial pressure (MAP) and systemic resistances decreased significantly with nicardipine. Inhaling a hyperoxic mixture was followed by a significant decrease in arterial pressure during placebo infusion; this was not observed during nicardipine. In contrast with systemic circulation, the response of the pulmonary circulation to different FiO2 levels was unaffected by nicardipine.

Metabolism of minaprine in human and animal hepatocytes and liver microsomes--prediction of metabolism in vivo

1. The metabolism of minaprine and its major metabolite p-hydroxyminaprine were studied using hepatocytes and liver microsomes from different species. Metabolism of this drug in vitro was then compared with in vivo data already published. 2. Our results showed that the major metabolic route (4-hydroxylation of the aromatic ring) is the same in the two experimental systems. Other in vivo biotransformation pathways (i.e. N-oxidation, reductive ring cleavage, N-dealkylation, oxidation) were also confirmed in hepatocytes. 3. Similar inter-species variability was observed both in vitro and in vivo. The present study has led to the same conclusion as previous in vivo metabolic investigations, namely, that metabolism in the dog quantitatively differs from that observed in other animal species. 4. These results clearly demonstrate that in vitro models (i.e. isolated hepatocytes and liver microsomes) are powerful tools in predicting the metabolic pathways of a drug in man and animal species.

Pharmacokinetics of navelbine after oral administration in cancer patients

The pharmacokinetic behavior of navelbine was investigated in 19 patients presenting with advanced cancers (mainly women with breast cancer). Navelbine was given orally at seven dose levels of up to 200 mg/week. For a given dose, patients received four successive weekly treatments. Five subjects also received two different doses. After drug administration, plasma was collected for 48 or 72 h and monitored for navelbine concentration by radioimmunoassay. Absorption of navelbine was very rapid after oral administration: maximal drug concentrations were reached within the first 1 or 2 h (Tmax, 0.9-1.75 h; cmax, 70.9-832.6 ng/ml), with absorption constants ranging from 0.85 to 2.42 l/h. A comparison of dose-normalised plasma concentration profiles revealed significant time dependence in six evaluable patients (P less than 0.001). Only four subjects who received low doses (less than or equal to 100 mg/week) exhibited time-independent kinetics. All of the five patients who were treated at different doses displayed apparent dose dependence (P less than 0.001). No individual profile was characterised by both time- and dose-independent pharmacokinetics. In all, 18 patients presented biphasic plasma concentration-decay patterns, and only 1 subject exhibited monophasic decay kinetics. The navelbine pharmacokinetic parameters obtained following oral administration were similar to those observed after i.v. bolus injection and were characterised by high oral clearance (0.43-1.45 1 h-1 kg-1), a large apparent volume of distribution (27.4-45.9 1/kg), and a long terminal half-life (24.2-56.5 h). Large intra- and inter-individual variations in pharmacokinetic parameters were observed. Moreover, after a high dose of 200 mg, an enterohepatic cycle and/or a delay in navelbine's absorption at a distal intestinal site as evidenced by a marked plasma level rebound was observed.

Strength recovery and muscle activation of the knee extensor and flexor muscles after arthroscopic meniscectomy. A pilot study

Maximal isokinetic strength and electromyographic activity of the operated leg were measured preoperatively and one, two, three, and eight weeks postoperatively after a partial medial meniscectomy by arthroscopy in a group of ten patients. Strength deficits, measured with a Kin-Com dynamometer using a static preloading protocol, were found in comparison with a group of matched healthy subjects preoperatively and three and eight weeks postoperatively in the knee extensors. These deficits were related to previously unreported modifications in the shape of the moment-angle curves and a tendency to lower activation levels of the vastus medialis (VM) but not the vastus lateralis or rectus femoris muscles. No deficits were found in the knee flexors preoperatively or three and eight weeks postoperatively, but the medial hamstrings activation level was lower for movements at 30 degrees per second. During flexion movements, the percentage of coactivation of the antagonist VM was significantly greater than healthy values at 30 degrees and 180 degrees per second. These results clearly indicate that neuromuscular recovery is not complete when return to work is advocated three to four weeks postoperatively. Such findings suggest the need for a rehabilitation program to promote recovery of the knee muscles in workers with a physically demanding occupation.

[Synovial cyst of the hip with venous compression. Diagnosis using x-ray computed tomography. A case report]

The authors report a case of synovial cyst developed about the serous bursae of the psoas iliaca muscle. It occurred in a 82 years old woman with a severe degenerative arthritis after hip dysplasia. The cyst has been revealed by a compression syndrome of the iliaca vein. Diagnosis has been made by CT. Physiopathology, clinics, diagnosis and treatment of this rare affection complete this case.

Pharmacokinetics of long-term propofol infusion used for sedation in ICU patients

The pharmacokinetics of propofol were determined in nine patients (seven men, two women, (mean +/- SD) 55.8 +/- 21.2 yr, 65.2 +/- 8 kg) requiring prolonged mechanical ventilation of their lungs. After an initial dose of 1-3 mg/kg, propofol was administered iv at 3 mg/kg/h for 72 h. Arterial blood samples were collected at selected times during and up to 72 h after infusion. Propofol whole blood concentrations were determined by high-performance liquid chromatography with fluorescence detection. Individual pharmacokinetic parameters were estimated by noncompartmental analysis. Derived pharmacokinetic parameters showed a long terminal phase (T1/2 = 1878 +/- 672 min), a large volume of distribution at steady state (Vdss = 1666 +/- 756 l), and a high total body clearance (Cl = 1.57 +/- 0.56 l/min). While the propofol terminal elimination half-life is longer than that previously reported, emergence from sedation after prolonged administration will be governed by both redistribution mechanisms arising from the large distribution volumes and elimination from the body.

Effects of age and antiepileptic drugs on plasma levels and kinetics of clobazam and N-desmethylclobazam

The authors monitored the plasma levels of clobazam (CLO) and its principal metabolite, N-desmethylclobazam (NCLO) during chronic treatment of more than 400 epileptic patients receiving different co-medications, such as phenytoin (PH), carbamazepine (CBZ), sodium valproate (VPA) and phenobarbital (PB). This study investigated the influence of age and antiepileptic drugs on plasma levels of CLO and NCLO. Plasma concentrations measured 3 hr after morning administration of CLO varied from 30 to 700 [formula; see text] for CLO, and from 160 to 7000 [formula; see text] for NCLO. Plasma levels of CLO were higher in patients aged 20-30 years. NCLO concentrations increased with age up to 20 years. Coadministered antiepileptic compounds significantly decreased maximal plasma levels of CLO. Moreover, PH and CBZ a significantly increased the plasma levels of NCLO. Results on the influence of CBZ on CLO kinetics were confirmed in a group of ten patients receiving PB and VPA and later PB, VPA and CBZ as CLO associated drugs. The influence of VPA on the pharmacokinetics parameters of CLO was also evaluated in a patient in the latter group.

Direct high-performance liquid chromatographic determination of the enantiomers of alfuzosin in plasma on a second-generation alpha 1-acid glycoprotein chiral stationary phase

A direct liquid chromatographic method was developed for the determination of the enantiomers of alfuzosin in human plasma, without derivatization, on a chiral alpha 1-acid glycoprotein column. The influence of pH, of uncharged organic solvents and of a cationic modifier (tetrabutylammonium) of the mobile phase on retention and enantioselectivity was evaluated. The enantiomers and an internal standard, structurally related to alfuzosin, were extracted from plasma with dichloromethane-diethyl ether from alkaline solution, then separated with a mobile phase of 0.025 M phosphate buffer (pH 7.4) containing 0.025 M tetrabutylammonium bromide-acetonitrile (94:6, v/v). The limit of quantification for each isomer was 1 ng/ml. The method has been applied to the determination of the pharmacokinetic profile of alfuzosin enantiomers in healthy volunteers after intravenous administration of the racemate.

[Plasma levels of metapramine and its 3 major metabolites in patients with depression. Results and preliminary interpretations]

Metapramine (Timaxel) and his three major metabolites (19148 RP, 23669 RP, 19749 RP) have been determined in the plasma of 18 depressed inpatients treated by the antidepressant drug (12 women and 6 men; 7 are smokers and 11 non-smokers). In a steady state, interindividual variability is very important, especially for 23669 RP. No significant correlation exists between normalized doses (mg.kg-1) and normalized plasma concentrations (ng.ml-1/dose mg.kg-1) of metapramine or anyone of its metabolites. The plasma metabolic ratios reveal also important intraindividual and interindividual variability. Two populations of patients seem to exist: extensive metabolizers and relatively poor metabolizers, without apparent clinical consequence because 23669 RP shows an antidepressant activity. Women seem, with equal normalized doses, to exhibit higher plasma levels of unchanged metapramine than men, due to a lower protein-binding rather than to a more active metabolism. In patients who received a poly-medication smoking seems not to induce desmethylation of metapramine. The plasma metabolic ratios, compared by the analysis of variance and the Wilcoxon distribution-free test, are significatively influenced by sex and not by tobacco-smoking.

Ion exchange paper adsorption and thin-layer chromatography for detection of chloroquine in urine for the study of chemosensitivity of Plasmodium falciparum

With a view to determining the chemosensitivity of Plasmodium falciparum to chloroquine, two qualitative tests for the detection of this antimalarial agent in urine were compared in Central African schoolchildren: the test of Dill and Glazko and a thin-layer chromatography technique involving ion exchange and extraction. Results obtained with 149 subjects showed the marked superiority in specificity and sensitivity of the chromatography test. This is of particular interest when selecting subjects before a therapeutic trial is undertaken. After administration of a single dose of chloroquine (10 mg kg-1) to 14 schoolchildren, both urinary detection tests gave positive results at 24 and 48 hours. However, on day 7 all results with the chromatography test were positive, while 57% of false negatives were recorded by the Dill and Glazko test.

Reversal of acute renal failure following percutaneous transluminal recanalization of an atherosclerotic renal artery occlusion

Thrombosis of the renal artery to a single functioning kidney is a known cause of anuric acute renal failure in atherosclerotic hypertensive patients. In the present report, recovery of renal function rapidly occurred following transluminal recanalization of the occluded artery with a 7F catheter after a 5-week period of anuria. The most interesting feature was that improvement of renal artery permeability was observed following a minimal interventional procedure.

Rapid determination of the benzodiazepine antagonist flumazenil, Ro 15-1788, by high performance liquid chromatography

A sensitive (2 ng/mL) and specific method for the determination of the benzodiazepine antagonist Ro 15-1788 or flumazenil is described. Following a simple extraction, the compound is analyzed by reversed phase high performance liquid chromatography (HPLC) and detection at 245 nm. The method was applied to plasma specimens collected from patients receiving a single dose of this drug.

Lack of effect of spiramycin on cyclosporin pharmacokinetics

1. The influence of spiramycin coadministration on cyclosporin pharmacokinetics was studied in five renal transplant patients. The plasma concentrations of cyclosporin were measured both by non-specific radioimmunoassay (RIA) and high-performance liquid chromatography (h.p.l.c.). 2. The kinetics of cyclosporin were followed before treatment, and after 1 day and then 2 weeks of oral treatment with spiramycin (3 X 10(6) iu, twice daily). The main pharmacokinetic parameters (the area under the plasma drug concentration-time curve, the maximum plasma drug concentration and the time to reach it) obtained both by RIA and h.p.l.c. were not modified by spiramycin cotreatment after 1 day, nor after 2 weeks of spiramycin administration. Therefore, the pharmacokinetics of cyclosporin (parent drug and parent drug plus metabolites) are not influenced by the coadministration of spiramycin macrolide at therapeutic dosage. 3. Spiramycin may be preferable to other macrolide antibiotics known to interact with cyclosporin such as erythromycin or josamycin.

[Determination of the optimal dose of bromazepam in the elderly]

The aim of our study was to determine in patients over 70 years, the optimal dose of Bromazepam. Seven patients were administered a unique dose of Bromazepam (3 mg), then repeated doses (1.5 mg) every 12 hours for 9 days. Cmax was 42.5 +/- 12 ng/ml in Tmax ranged from 2 to 12 hours after the first dose-concentrations of Bromazepam at steady-state were between 79 and 157 ng/ml. Half life was 30.5 +/- 14.7 hrs for the unique and the repeated doses. Sleeping was noted for concentrations over 40 ng/ml. The dose of 1.5 mg bid is recommended in old patients.

A rapid HPLC procedure for the simultaneous determination of chloroquine, monodesethylchloroquine, diazepam, and nordiazepam in blood

Chloroquine, monodesethylchloroquine, diazepam, and nordiazepam levels are simultaneously determined in whole blood or plasma by HPLC. Papaverine is used as internal standard, and the analysis is performed after protein-binding hydrolysis, absorption on Extrelut, and elution with diethyl ether/methylene chloride (70:30 v/v). UV detection is used at 343 nm for 12 min, then changed to 242 nm. There are two mobile phases with two flow rates. The procedure requires 30 min, is reproducible, sensitive (8-10 ng/mL for chloroquine and its metabolite, 4 ng/mL for diazepam and nordiazepam), and selective, especially towards other antimalarial agents and drugs like adrenaline or barbiturates, which may be used in chloroquine poisoning therapy. It can be used for pharmacokinetic studies, therapeutic control, to establish the diagnosis and prognosis of a chloroquine poisoning, and to follow and optimize treatment.

Pharmacokinetics, brain distribution and pharmaco-electrocorticographic profile of zolpidem, a new hypnotic, in the rat

Zolpidem [N,N-6-trimethyl-2-(4-methylphenyl)imidazo[1,2-a]pyridine-3- acetamide] administered as the hemitartrate salt has proven to be an effective hypnotic agent in animals and humans. This study describes the pharmacokinetic behavior of zolpidem in plasma and brain of rat after i.v. and p.o. administration of 2.63 mg.kg-1 of [14C]zolpidem (dose expressed as the base). Autoradiography was used to examine the regional distribution of the compound and the metabolic profile of zolpidem in the plasma and brain was also investigated. The pharmacokinetic data were related to electrocorticogram power spectral analysis. After i.v. administration, the disappearance of zolpidem from plasma fitted a biexponential model with a rapid phase of 0.2 to 0.3 hr and a slower phase of 1.3 to 1.5 hr. After p.o. dosing, peak plasma concentrations where already attained at 15 min (first sampling time). Independent of the route of administration, the concentrations of zolpidem in the brain at shorter times were 30 to 50% those of the plasma values. Furthermore, up to 1 hr, zolpidem accounted for 80 to 90% of brain radioactivity. The rate of disappearance from brain paralleled that from plasma. Autoradiographic studies confirmed the rapid absorption and elimination of zolpidem as well as the relatively homogenous distribution throughout the brain. Electrocorticogram analysis in immobilized rats after i.v. administration of zolpidem showed a rapid onset and a short-acting sedative effect compatible with the kinetic profile of the parent compound. Metabolites of zolpidem displayed a poor penetration into the brain and no significant hypnotic activity. At the dose of zolpidem used, no alteration of the sleep pattern was observed.

Effect of renal failure on the pharmacokinetics of ethyl loflazepate (Victan) in man

The kinetics of ethyl loflazepate were studied in patients with various degrees of renal failure. A strong correlation was noted between urinary excretion of metabolite loflazepate and creatinine clearance. In contrast, elimination half-life and total plasma clearance of the sum of loflazepate + descarboxyloflazepate seemed to be independent of the degree of renal impairment. These results indicate the absence of a risk of accumulation of the 2 main and active metabolites of ethyl loflazepate in patients with renal failure.

Inversely related evolution of growth hormone and prolactin secretions in long-term tissue cultures of human pituitary adenomas from acromegalic patients

Pituitary tumoral tissue from 20 acromegalic patients was cultured for up to 120 d in a medium containing 5 nM cortisol. In all cultures, growth hormone (GH) release decreased. At the beginning of the culture, prolactin (PRL) was detected in 18 adenomas, varying from 0.5 to 1000 ng per flask per day. Thereafter, in 10 cases PRL secretion increased from 3 to 50 times the basal level, most frequently after a lapse of 9 to 30 d. PRL secretion remained low in three cases, undetectable in one case only. When added at 350 nM, cortisol increased GH secretion up to 20-fold and simultaneously decreased PRL secretion by as much as 10% of the basal level. Withdrawing cortisol reversed the situation. Immunocytochemical studies of the tumor at surgery showed, besides GH immunoreactive (IR) cells, PRL-IR cells (from rare cells to 10% of total cells) in 15 adenomas, correlating with the first days of culture PRL levels. In cultured explants, mitoses were never found. In 5 nM cortisol medium, the number of GH-IR cells decreased and PRL-IR cells increased or appeared. With 350 nM cortisol, the number of GH-IR cells increased, and PRL-IR cells were scarce or absent. Immunoreactivities for GH and PRL were found in different cells. Care was taken to exclude cultures containing normal pituitary tissue, and because no mitoses were found, these results suggest that most somatotropic adenomas can reversibly shift their secretion from GH to PRL in culture. This capacity to secrete PRL, hidden or low in vivo, is revealed by the favorable low cortisol conditions present in vitro.