Molecular lipophilicity determination of a huperzine series by HPLC: comparison of C18 and IAM stationary phases.

Two hydrophobic parameters (logkw-C18 and logkw-IAM, respectively) of a huperzine A series were extrapolated by high performance liquid chromatography (HPLC) using both C18 and immobilised artificial membrane (IAM) columns. A mathematical correlation between C18 and IAM hydrophobic parameters was completed, suggesting a similar behaviour on both columns. This behaviour was principally led by hydrophobic forces.

[Pharmacokinetics in the elderly].

Physiological changes that occur in the aging process may directly affect drug pharmacokinetics. In the absence of disease or other pathologic conditions, age-related changes in pharmacokinetics principally affect drug absorption, distribution, metabolism or elimination. One factor that does change consistently with age is renal clearance, consequently a common pharmacokinetic change is reduced drug clearance, especially for drugs excreted largely unchanged by the kidneys.

Development of a rapid RP-HPLC method for the determination of clonazepam in human plasma.

A rapid and sensitive high-performance liquid chromatography method with UV detection was developed for the determination of clonazepam in human plasma using 3-methylclonazepam, as internal standard. A one-step extraction of both compounds was performed with a mixture of hexane/ethyl acetate (90:10, v/v). The HPLC analysis was carried out on a Nova Pak((R)) C(18) reversed-phase column with a mobile phase of acetonitrile-0.

Direct injection HPLC micro method for the determination of voriconazole in plasma using an internal surface reversed-phase column.

A direct plasma injection liquid chromatographic method has been developed for the determination of a new triazole antifungal agent, voriconazole, using an internal surface reversed phase column. Therapeutic drug monitoring of voriconazole is relevant for patient management, especially in the case of drug-drug interaction. The method is easy to perform and requires 10 microL of a plasma sample.

Rapid high-performance liquid chromatographic measurement of buspirone in human plasma after overdose.

For toxicological purposes, a rapid reversed-phase high-performance liquid chromatographic method was developed for the determination of the anxiolytic drug, buspirone, in human plasma. A liquid-liquid procedure was used to extract this compound from plasma in the presence of an internal standard, quinupramine. The analysis was performed on a Spherisorb S5 C8 analytical column with UV detection at 240 nm.

Comparison of patient questionnaires and plasma assays in intentional drug overdoses.

Our aim was to explore the agreement between clinically collected information on purported drug intake and plasma data in intentional drug overdose. We included all subjects with intentional drug overdose above 15 years of age consecutively admitted to the Emergency Department of the University Hospital during 4 months. Information about drugs used and sources of this information was collected and compared to presence of drug in plasma, concerning four drugs with high toxic potential (tricyclic antidepressants, meprobamate, paracetamol and ethanol).

HPLC microdetermination of flurbiprofen enantiomers in plasma with a glycopeptide-type chiral stationary phase column.

A rapid and stereospecific HPLC micromethod to quantify flurbiprofen enantiomers was developed. Both flurbiprofen enantiomers and indomethacin, used as internal standard, were extracted with methylene chloride from 100 microL of acidified plasma. The resolution of the R- and S-forms was performed on a bonded vancomycin chiral stationary phase (Chirobiotic V) with 20% of tetrahydrofuran in ammonium nitrate (100 mM, pH 5) as mobile phase.

A simple high-performance liquid chromatographic method for detection of hydroxyzine in human plasma after overdose.

Introduction: Hydroxyzine, a piperazine H1-receptor antagonist, is effective in generalised anxiety disorder. For toxicological purposes, a simple reversed-phase high-performance liquid chromatographic assay was developed for the detection of hydroxyzine in human plasma.

Methods: A liquid-liquid procedure was used to extract the drug from plasma in the presence of an internal standard (clothiapine).

Synthesis, antimalarial activity, and molecular modeling of new pyrrolo[1,2-a]quinoxalines, bispyrrolo[1,2-a]quinoxalines, bispyrido[3,2-e]pyrrolo[1,2-a]pyrazines, and bispyrrolo[1,2-a]thieno[3,2-e]pyrazines.

Three pyrrolo[1,2-a]quinoxalines, 15 bispyrrolo[1,2-a]quinoxalines, bispyrido[3,2-e]pyrrolo[1,2-a]pyrazines, and bispyrrolo[1,2-a]thieno[3,2-e]pyrazines were synthesized from various substituted nitroanilines or nitropyridines and tested for their in vitro activity upon the erythrocytic development of Plasmodium falciparum strains with different chloroquine-resistance status. Bispyrrolo[1,2-a]quinoxalines showed superior antimalarial activity with respect to monopyrrolo[1,2-a]quinoxalines. The best activity was observed with bispyrrolo[1,2-a]quinoxalines linked by a bis(3-aminopropyl)piperazine.

[Pharmacologic basis for using paracetamol: pharmacokinetic and pharmacodynamic issues].

The advantage of paracetamol (acetaminophen) is that it can be administered via the oral, intravenous or rectal routes. The last mentioned differs from the oral route in the slow and irregular absorption of the active substance. At therapeutic concentrations, the pharmacokinetics of paracetamol are linear--that is, independent of the dose, and constant with repeated administration.

Diffusion of arylpropionate non-steroidal anti-inflammatory drugs into the cerebrospinal fluid: a quantitative structure-activity relationship approach.

A quantitative structure-activity relationship (QSAR) analysis of a series of arylpropionic acid non-steroidal anti-inflammatory drugs (NSAIDs) has been performed to determine which physicochemical properties of these compounds are involved in their diffusion into the cerebrospinal fluid (CSF). The penetration of eight arylpropionic acid derivatives into CSF was studied in male Wistar rats. After intraperitoneal administration of each compound (5 mg/kg), blood and CSF samples were collected at different times (0.

Simultaneous determination of four antipsychotic drugs in plasma by high-performance liquid chromatography. Application to management of acute intoxications.

A specific reversed phase-high pressure liquid chromatography (RP-HPLC) method has been developed for the simultaneous determination of clozapine (CZP), loxapine (LXP), zuclopenthixol (ZPT) and flupenthixol (FPT) in plasma. These four antipsychotic drugs are frequently used for the treatment of schizophrenia and other neuropsychiatric diseases. Carpipramine, a dihydrodibenzazepine, was used as an internal standard (I.

High-performance liquid chromatographic method with diode array detection for identification and quantification of the eight new antidepressants and five of their active metabolites in plasma after overdose.

A high-performance liquid chromatographic method is described for the determination of selective serotonin reuptake inhibitors (fluvoxamine, paroxetine, sertraline, fluoxetine, citalopram, mirtazapine), serotonin norepinephrine reuptake inhibitors (milnacipram, venlafaxine), a noradrenergic and specific serotoninergic antidepressant (mirtazapine), and five pharmacologically active metabolites (desmethylcitalopram, didesmethylcitalopram, norfluoxetine, O-desmethylvenlafaxine, desmethylmirtazapine). After a double-step liquid-liquid extraction, compounds are separated on a Symmetry C8 column eluted with a gradient of acetonitrile-phosphate buffer 10 mM pH 3.8 and detected at 230 nm and 290 nm.

Potential of immobilized artificial membrane chromatography for lipophilicity determination of arylpropionic acid non-steroidal anti-inflammatory drugs.

Molecular lipophilicity can be expressed by logP or more conveniently by logk, i.e. determined by the traditional shake-flask technique or by liquid chromatography.

Rapid high-performance liquid chromatographic measurement of amisulpride in human plasma: application to manage acute intoxication.

Amisulpride, a substituted benzamide derivative, is a second-generation (atypical) antipsychotic and is effective as maintenance therapy in patients with schizophrenia. For toxicological purpose, a rapid RP-HPLC assay was developed for the determination of amisulpride in human plasma. A linear response was observed over the concentration range 100-1000 ng/ml.

Derivatization of (+/-)-5-[(2-methylphenoxy)methyl]-2-amino-2-oxazoline, an imidazoline binding sites ligand, with (+)-(R)-alpha-methylbenzyl isocyanate for drug monitoring purposes.

The derivatization of racemic 5-[(2-methylphenoxy)methyl]-2-amino-2-oxazoline, developed as an imidazoline binding sites ligand, with (+)-(R)-alpha-methylbenzyl isocyanate was performed in chloroform. The reaction led to two pairs of diastereomers, which were separated by RP-HPLC. A kinetic study of the derivatization reaction was achieved in order to establish conditions suitable for experimental drug monitoring.

High-performance liquid chromatographic method with diode array detection to identify and quantify atypical antipsychotics and haloperidol in plasma after overdose.

For toxicological purposes, an HPLC assay was developed for the simultaneous determination of haloperidol and atypical antipsychotics (risperidone, 9-hydroxyrisperidone, olanzapine, clozapine) in human plasma. After a double-step liquid-liquid extraction, compounds were separated on a C(8) column eluted with a gradient of acetonitrile and phosphate buffer 50 mM pH 3.8.

Rapid HPLC measurement of buflomedil in plasma in poisoning cases.

A rapid high-performance liquid chromatographic method for the determination of buflomedil in human plasma is described. It requires a single liquid-liquid extraction step from 1 mL of plasma with diethyl ether followed by chromatography on a Nova Pak C(18) reversed-phase column and detection by ultaviolet light. Metoclopramide was used as internal standard.

[Plasmatic dosage of antiretroviral drugs by high performance liquid chromathography ].

A high-performance liquid chromatographic method has been developed for the determination of eight antiretroviral drugs (amprenavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, efavirenz and nevirapine) in a single run. After a liquid-liquid extraction with diethylether, the antiretroviral drugs are separated on a Stability RP18 column eluted with a gradient of acetonitrile and phosphate buffer (50 mM pH 5.65).

[Pharmacokinetics in the elderly].

Physiological changes that occur in the aging process may directly affect drug pharmacokinetics. In the absence of disease or other pathologic conditions, age-related changes in pharmacokinetics principally affect drug absorption, distribution, metabolism or elimination. One factor that does change consistently with age is renal clearance, consequently a common pharmacokinetic change is reduced drug clearance, especially for drugs excreted largely unchanged by the kidneys.

Pharmacokinetic interaction between high-dose methotrexate and oxacillin.

An 18-year-old man received two high-dose methotrexate cycles for the treatment of an osteosarcoma. Fifteen grams of methotrexate were infused over 6 hours. During the second cycle, co-administration of oxacillin (1g/8h) resulted in prolonged and marked elevation of methotrexate plasma concentrations.

Determination of mirtazapine and its demethyl metabolite in plasma by high-performance liquid chromatography with ultraviolet detection. Application to management of acute intoxication.

Mirtazapine is a new centrally acting noradrenergic and specific serotonin antidepressant, with an active demethyl metabolite. For toxicological purposes, a specific and accurate RP-HPLC assay was developed for the simultaneous plasma determination of these compounds. A linear response was observed over the concentration range 50-500 ng/ml.

High-performance liquid chromatographic method for the simultaneous determination of the six HIV-protease inhibitors and two non-nucleoside reverse transcriptase inhibitors in human plasma.

A selective and sensitive high-performance liquid chromatographic (HPLC) method has been developed for the determination of the six human immunodeficiency virus (HIV)-protease inhibitors (amprenavir, indinavir, lopinavir, nelfinavir, ritonavir, and saquinavir) and the non-nucleoside reverse transcriptase inhibitors (efavirenz and nevirapine) in a single run. After a liquid-liquid extraction with diethyl ether, the six protease inhibitors and the two non-nucleoside reverse transcriptase inhibitors are separated on a Stability RP18 column eluted with a gradient of acetonitrile and phosphate buffer 50 mmol/L pH 5.65.

Influence of a polymeric formulation of ketoprofen on its diffusion into cerebrospinal fluid in rats.

Poly(D,L)lactide nanocapsules (NCs) have been proposed as an alternative carrier for many drugs. We investigated the influence of this formulation on the pharmacokinetics of ketoprofen in the plasma and cerebrospinal fluid (CSF). Male Wistar rats were given intraperitoneal dose of ketoprofen (5 mg/kg) in a suspension of NCs or in a carboxymethylcellulose (CMC) solution (reference preparation).

Intraosseous lidocaine provides effective analgesia for percutaneous vertebroplasty of osteoporotic fractures.

Purpose: To assess the safety and efficacy of intraosseous lidocaine (IL), in comparison with iv nalbuphine and propacetamol (NP) for analgesia during percutaneous vertebroplasty (PV) in order to avoid general anesthesia in elderly patients.

Methods: Patients (age 68 +/- 13 yr, weight 66 +/- 6 kg) undergoing PV for osteoporotic fractures were randomized prospectively into two groups: NP (n=50) and IL (n=50). All patients were premedicated (oral hydroxyzine 1 mg.