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S Pichini

Publications and source records attributed to S Pichini.

64 records · Page 4Linked to original sources
PubMed1991

Determination of naltrexone and 6 beta-naltrexol in plasma by high-performance liquid chromatography with coulometric detection.

A simple and reliable reversed-phase high-performance liquid chromatographic method with coulometric detection is described for the quantitation of naltrexone and its metabolite, 6 beta-naltrexol, in plasma samples of healthy volunteers who received orally 50 mg of naltrexone. The analytes and the internal standard, naloxone, are extracted with an octadecyl solid-phase extraction column before chromatography. The mobile phase is 0.01 M potassium phosphate (pH 3)-acetonitrile (85:15, v/v) and it is pumped at 0.8 ml/min. The coulometric detector is formed by two electrodes set at +0.20 V and +0.70 V, with a palladium reference electrode. The limit of quantitation observed was 5 ng/ml for both naltrexone and 6 beta-naltrexol. This method can be used to investigate pharmacokinetic parameters of different pharmaceutical preparations of this opioid antagonist.

Chromatography, High Pressure Liquid↗
PubMed1991

Epileptic patients refractory to drug therapy.

We compared two groups of patients with idiopathic epilepsy, 41 patients whose seizure frequency was not controlled by adequate therapy and 39 patients in good seizure control, in respect of hematology, kidney and liver function tests, serum IgG, IgA and IgM concentrations and drug concentrations. The only difference that emerged were in the serum immunoglobulins, which were raised in the drug refractory group, significantly (p less than 0.01) so in the case of IgG. Failure of seizure control did not depend on inadequacy of drug dose or of blood concentration. Although the serum Ig changes do not warrant the assumption of an immunological origin for drug resistance, they do suggest a useful research line.

Adult↗
PubMed1991

A highly sensitive chemiluminescent assay for glycerylphosphorylcholine in human seminal plasma.

Glycerylphosphorylcholine (GPC), one of the major phosphorus-containing-choline compounds of seminal plasma, is secreted mainly by the epididymal epithelium under androgenic control. This study reports a new method that uses chemiluminescence to determine seminal GPC content, comparing it with a spectrophotometric technique. The results, obtained with both techniques studying 20 fertile patients (as control), 35 infertile patients with normospermia, 23 infertile patients with oligozoospermia and impaired motility and 9 patients with excretory azoospermia, demonstrate that the GPC chemiluminescent assay is more sensitive, simple and rapid than the spectrophotometric assay. Our data confirm that GPC may be used as a marker of vas deferens and ejaculatory duct perviousness, suggesting a possible role of this glycerophosphodiester in sperm motility.

Glycerylphosphorylcholine↗
PubMed1991

Fat body mass and pharmacokinetics of oral 6-mercaptopurine in children with acute lymphoblastic leukemia.

To evaluate the reasons for the wide variability in bioavailability of orally administered 6-mercaptopurine in children with acute lymphoblastic leukemia, we studied several pharmacokinetic parameters of the drug in 18 affected children receiving remission maintenance therapy, and compared them with their anthropometric data and with the results of intestinal function tests. No correlation was found between estimates of small intestinal absorption (the oral lactose tolerance test and 1 h blood xylose test) and 6-mercaptopurine serum levels. Of the anthropometric measurements considered, only the weight/height percentile (an index of the fat body mass) strongly and linearly correlated with the area under the curve of 6-mercaptopurine. The dose of 75 mg of 6-mercaptopurine/m2 of body surface resulted in higher serum concentrations in children below the 75th percentile than in those with a weight/height ratio exceeding the 75th percentile. In conclusion, these data caution about the risk of underdosing 6-mercaptopurine in overweight children when administering it on the basis of body surface area.

Administration, Oral↗
PubMed1989

Influence of antacids on the bioavailability of glibenclamide.

A single oral dose of glibenclamide (2.5 mg) was given to eight healthy volunteers in a randomized cross-over study after a standardized fasting and breakfast (374 kcal), with or without a concomitant intake of 10 ml of antacid suspension. Serum glibenclamide levels were determined by means of a specific radioimmunoassay method. The areas under the blood concentration-time curves (AUC0-infinity), with or without antacid, were 408.17 +/- 168.25 and 307.9 +/- 84.13 ng/ml (p less than 0.05), respectively. The peak concentrations of 96.88 +/- 49.9 and 66.19 +/- 32.35 ng/ml/h (p less than 0.05) with or without antacid, were reached in 4.13 and 3.81 h, respectively. Values of tmax, Vd and t1/2 were not affected by the presence of the antacid. A 33% increase in bioavailability of glibenclamide emerged, as seen from the respective AUC values, but no clinically remarkable effect was observed in the subjects.

Adult↗
PubMedDate not supplied

The role of liquid chromatography-mass spectrometry in the determination of heroin and related opioids in biological fluids.

The opioid most commonly sold in the illicit market is heroin. This substance, classified as an analgesic narcotic drug, has an extremely short half-life, and it is rapidly metabolized to 6-monoacetyl-morphine and further to morphine. Morphine is principally metabolized by conjugation to morphine-3 and morphine-6 glucuronides. Morphine itself is a potent analgesic that is frequently used in the pharmacological intervention of cancer pain. The toxicological and clinical evaluation of heroin and morphine have stimulated pharmacokinetic studies in human and animal models. Although a number of methods exist to determine opiates and their metabolites, liquid chromatography (LC) appears to be the technique that can separate without any pretreatment the lipophilic and the hydrophilic analytes of the complete metabolic profile of heroin and/or morphine. Moreover, mass spectrometry (MS) used as a detector for liquid chromatography is unique, because it offers universality and selectivity. Furthermore, efforts have been made to develop LC/MS interfaces that could overcome the previous problem of poor sensitivity. For this reason, in recent years LC combined with MS has been applied to the analysis of opiates--parent drugs and metabolites--in biological fluids. This article reviews the existing literature on the determination, using liquid chromatography coupled to mass spectrometry, of opiate metabolites found in different biological matrices after the administration of the parent compounds.

Body Fluids↗
PubMedDate not supplied

Simultaneous determination of heroin 6-monoacetylmorphine, morphine, and its glucuronides by liquid chromatography--atmospheric pressure ionspray-mass spectrometry.

A new analytical technique has been developed for the simultaneous determination of heroin, 6-monoacetylmorphine, morphine, morphine-6- and 3-glucuronides, and codeine in serum using liquid chromatography coupled with ionspray mass spectrometry. The analytes and the internal standard, nalorphine, were subjected to solid-phase extraction (SPE) using ethyl SPE columns before chromatography. The chromatographic separation of the analytes was achieved using a normal phase column and a water-methanol-acetonitrile-formic acid mobile phase at a flow rate of 230 microL/min. The mass spectrometer was operated in selected-ion monitoring mode. Under these conditions, the limit of quantitation was 0.5 ng/ml for heroin, 4 ng/ml for 6-monoacetylmorphine, 4 ng/ml for morphine, 1 ng/ml for morphine-3-glucuronide, 4 ng/ml for morphine-6-glucuronide, and 4 ng/mL for codeine. Serum levels of heroin metabolites were determined in C57BL/6 inbred mice after a dose of 20 mg/kg heroin administered subcutaneously. 6-monoacetylmorphine showed a peak concentration of 0.93 micrograms/mL serum at 3 min, whereas morphine and morphine-3-glucuronide achieved their peak concentrations of 9.6 and 2.9 micrograms/mL serum at 10 and 20 min, respectively. Finally, the absence of morphine-6-glucuronide and codeine excluded the possibility of their formation from morphine in this animal model.

Animals↗
PubMedDate not supplied

Immunologic aspects of carbamazepine treatment in epileptic patients.

Immune abnormalities have been found in epileptic patients receiving antiepileptic drugs (AEDs). Phenytoin (PHT) produces a decrease in serum IgA and IgM levels and a decrease in blastic transformation of circulating lymphocytes stimulated with phytohemoagglutinin (PHA). The effects of carbamazepine (CBZ) on the immune response are still conflicting. To elucidate the effects of CBZ on some immunologic parameters, serum concentrations of IgA, IgG, IgM, the phagocytosis and killing properties of polymorphonuclear leukocytes (PMNs), the cytotoxic activity of natural killer cells and the response of lymphocytes to mitogenic agents were studied. Forty healthy individuals and 39 epileptic patients treated with carbamazepine (CBZ) monotherapy (age range 18-40 years) entered the study. Student's t test was used to evaluate the data. CBZ had no effect on the serum immunoglobulin concentrations or on lymphocytic reactivity to phytohemoagglutinin (PHA) mitogen. CBZ produced a significant enhancement of phagocytosis and killing properties of PMNs and an increase in natural killer (NK) cell activity. Therefore, a negative effect of CBZ therapy on the immune system was not observed in this study.

Adolescent↗