Improved selectivity for high-performance liquid chromatographic determination of clonazepam in plasma of epileptic patients.

We report a high-performance liquid chromatography method for clonazepam determination in plasma. The use of a synthetic silica-based stationary phase markedly improved clonazepam resolution compared to standard reversed-phase columns. A liquid-liquid extraction was used, associated with reversed-phase chromatography, gradient elution and ultraviolet detection.

Stability of rifampin in plasma: consequences for therapeutic monitoring and pharmacokinetic studies.

Interest in determining plasma levels of rifampin for adjustment of dosage regimens has increased, but conflicting results exist concerning rifampin stability. The authors developed a high-performance liquid chromatography assay to monitor rifampin plasma concentrations that was used to study the possible degradation of rifampin in plasma samples. This report describes the stability of rifampin in plasma kept at an ambient temperature for 24 hours or stored at -20 degrees C for 2 weeks.

Nebulization and anti-Pseudomonas aeruginosa activity of colistin.

Colistin aerosols are frequently administered to patients with cystic fibrosis. However, questions arise concerning the effect of both jet and ultrasonic nebulizers on the properties of the drug. The aim of this study was to characterize the anti-Pseudomonas aeruginosa (PA) activity of colistin after jet (Pari LL) and ultrasonic (DP100) nebulization.

Effect of tamoxifen on the pharmacokinetics of theophylline in rats.

The effect of tamoxifen on the pharmacokinetics of theophylline was investigated in male Sprague-Dawley rats. The oral administration of tamoxifen at a dose equal to 40 mg kg-1 48 h before the intravenous injection of theophylline 10 mg kg-1, significantly (P < 0.05) increased the clearance of theophylline by 39%, with no apparent effect on the volume of distribution.

Deposition of amphotericin B aerosols in pulmonary aspergilloma.

The aim of the present study was to characterize amphotericin B aerosols nebulized by ultrasonic and jet nebulizers and to study their deposition and pharmacokinetics in patients with pulmonary mycetoma. The aerodynamic behaviour and pulmonary deposition of amphotericin B particles were measured using a direct isotopic method based on stable labelling of the drug with 99mTc. Each nebulizer was bench tested for inhaled mass and particle size distribution.

Pharmacokinetics of paracetamol in the neonate and infant after administration of propacetamol chlorhydrate.

The pharmacokinetic parameters of paracetamol were studied after 15 min intravenous infusion of 15 mg/kg of propacetamol (Prodafalgan) in 5 neonates aged less than 10 days and 7 infants aged between 1 and 12 months. Blood was sampled at 0, 0.5, 2 and 6 h after the first intravenous infusion of propacetamol.

[Accidental chloral hydrate poisoning].

A 42-year-old woman had an accidental overdose of chloral hydrate due to repeated absorption of a therapeutic dose of chloral syrup for insomnia. The total ingestion was estimated at 8 g. Overnight slight loss of consciousness associated with severe cardiac arrhythmia (bigeminia ventricular extra-systole) needed admission to the intensive care unit and intravenous lignocaine for two days.

[Study of residual levels of delayed-action neuroleptics].

Pharmacokinetics of the depot antipsychotics are unclear and mainly depend on releasing from the depot site (according to a "flip-flop" model). Few data are available on residual plasma concentrations of those drugs. We have practiced 38 blood determinations among 15 patients treated by long-acting neuroleptics (10 by fluphenazine decanoate, 4 by flupentixol decanoate and 1 by pipotiazine palmitate).

[Severe chloroquine poisoning. Favourable outcome with diazepam therapy. A toxicokinetic study].

A severe chloroquine poisoning, featuring indicators of bad prognosis, has been treated by a diazepam-type therapy. The outcome was favourable in a dramatic way. A toxicokinetic study showed very high chloroquine plasmatic levels, consistent with the severity of the poisoning.

Effects of prenatal exposure to diazepam on exploration behavior and learning retention in mice.

Diazepam (2 mg/kg, DZP) or placebo were administered by oral gavage throughout gestation in 40 mice. The automatic hole board test for mice (Boissier and Simon) was used to measure the locomotor activity and the number of holes explored by the offspring (mean age 30.6 days).

Oxidative polymorphism of dextromethorphan in a Burundi population.

The wide availability, metabolism by the same cytochrome P450 as debrisoquine and, above all, the inocuity of dextromethorphan (DMP) favour the frequent choice of this drug as the test substance in determining oxidation phenotypes. 100 healthy Burundian volunteers (94 m and 6 f) in this study ingested 50 mg DMP bromhydrate, i.e.

[Is the qualitative research of benzodiazepines by the EMIT method and diazocopulation in accidental poisoning in children relevant?].

A retrospective study was undertaken to evaluate the relevance of benzodiazepine detection in 42 children with accidental poisoning. Immunoenzymatic assay for benzodiazepine in serum and colorimetric method in urines were positive respectively in 3 and 4 patients only. Several reasons could explain these results: the high detection threshold, the different drug reactivity according to the molecular structure and the great delay between intoxication and toxicology analysis.

Accidental lidocaine overdosage in an infant.

A one month old child inadvertently received an intravenous bolus injection of 50 mg of lidocaine instead of contrast iodine. The clinical picture comprised collapse, respiratory arrest, convulsions and coma. The calculated maximum level of lidocaine was 5.

[Epidemiology of pediatric paracetamol poisoning (retrospective analysis of calls received by the Poison Control Center of Tours)].

The authors analysed 101 phone calls received in 3 years and 8 months at the Poison Control Center of Tours for paracetamol poisoning in children under 15 years of age. 70% of children were between 1 and 5 years old, 15% under 1 year and 15% over 5 years old. The kind of poisoning differ according to age: iatrogenic in 93% of cases under 1 year old (medication given by parents; error in dosage); accidental in 85% of cases between 1 and 5 years old and "willful" poisoning (43%) or accidental (36%) over 5 years old.

[Are theophylline determinations useful to the clinician during treatment with a sustained-release form of theophylline?].

The aims of the study were the correlation between dosage and plasmatic levels of slow release theophylline and the reason for dosage adjustment. 64 pharmacokinetic studies were performed in 58 asthmatic children between 17 months and 16 years. Plasmatic levels of theophylline were performed by fluoroimmunology technique at H0 (before the dose) 2 (H2), 4 (H4), 6 (H6) and 8 (H8) hours after the dose of slow release theophylline.

[Prolonged mydriasis caused by Lamaline].

Atropine derivatives. The presence of atropine derivatives in numerous combined medicines is often ignored or reflected. A case report of prolonged bilateral non reactive mydriasis with "cycloplegia", linked with the utilisation of a therapeutic dose of Lameline suppositories raises the question of individual susceptibility, with particular ocular sensitivity.

Is monitoring plasma levels of netilmicin necessary in neonates?

Thirty-two neonates were treated with netilmicin 3 mg/kg every 12 h by IV infusion for 30 min for suspected infections, colonization, or proven infections. Pharmacokinetic studies were performed in order to define the situations in which monitoring of plasma levels would be appropriate. Mean plasma levels were within the therapeutic range and did not differ in fullterms and preterms.

[Comparison of plasma levels of amoxicillin administered by oral and intravenous routes in neonatal bacterial colonization].

Twenty-one full-term neonates who had a diagnosis of bacterial colonization were randomly assigned to receive amoxicillin 40 mg.kg-1 every 12 hours by either IV or oral route. Plasma levels of amoxicillin were assayed by HPLC at 0.