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A Marzo

Publications and source records attributed to A Marzo.

At least 91 records · Page 5Linked to original sources
PubMed1987

Gas chromatographic evaluation of trapidil and its desethyl metabolite in biological fluids for pharmacokinetic and bioavailability investigations.

This paper describes a suitable and cost-saving method for quantitative analysis of trapidil (5-methyl-7-diethylamino-s-triazolo [1,5-a]pyrimidine) and its desethyl metabolite in plasma and urine for pharmacokinetic and bioavailability investigations. Trapidil and desethyl-trapidil were extracted from plasma, concentrated and injected into the gas chromatography without any derivatization process. The authors suggest a series of internal standards. A thermoionic specific detector enables high sensitivity to be achieved, i.e. 20 ng/ml, and good specificity. The method is cost-saving in that it allows about 30 analyses a day to be performed without automatic integrators, and about 50 analyses a day with these integrators.

Biological Availability↗
PubMed1986

Gas chromatographic evaluation of the antimycotic democonazole for pharmacokinetic and bioavailability studies in man and animals.

A new gas chromatographic method for quantitative determination of 1-[2,4-dichloro-beta-[2-(p-chlorophenoxy)ethoxy] styryl]imidazole (demonoconazole), employing an electron capture detector, was developed. All analytical parameters were satisfactory within the range between 5 ng and 1 micrograms per ml of plasma, which means 20 pg-2 ng as absolute sensitivity. This method therefore is specific and sensitive enough for the quantitative determination of the drug in biological samples for pharmacokinetic and bioavailability studies to be performed in animals and human beings.

Animals↗
PubMed1985

Gas-liquid chromatographic evaluation of bencyclane in biological samples for pharmacokinetic and bioavailability investigations: comparison of two analytical methods.

Analytical conditions that allow bencyclane, a vasodilator, to be evaluated in biological samples for pharmacokinetic and bioavailability investigations are reported. Two gas chromatographic methods were developed, one employing a flame-ionization detector, reaching a sensitivity of 0.5-1 micrograms/ml, and the other employing a thermionic specific detector and reaching a sensitivity of 10 ng/ml. The extraction recovery, reproducibility and specificity were all satisfactory with both methods. The former method is suitable for chemical quality controls and the latter has a sufficient sensitivity and reproducibility for determination of the drug in biological samples as required in pharmacokinetic investigations.

Animals↗
PubMed1985

Correlation between digoxin plasma levels and arterial blood pH.

The correlation between arterial blood pH and digoxin plasma levels was studied after digoxin (Eudigox) administration a) in a single p.o. dose, b) in a steady state p.o. regimen, or c) i.v. The clinical trial was carried out on 26 male hospitalized patients selected and divided into groups according to their arterial blood pH values, which ranged between 7.20 and 7.53. Arterial blood pH proved to be directly correlated with digoxin plasma levels and with the corresponding AUC and inversely with the total plasma clearance of the drug. The data may explain the strongly reduced activity shown by digoxin in patients suffering from respiratory acidosis in clinical practice.

Acidosis, Respiratory↗
PubMed1984

Gas--liquid chromatographic evaluation of lofemizole in biological samples for pharmacokinetic investigations. Comparison of two analytical methods.

The present paper reports the analytical conditions allowing lofemizole, a new non-steroidal anti-inflammatory drug, to be evaluated in biological fluids for pharmacokinetic and bioavailability investigations. The first approach led to an N-methyl derivative of lofemizole which could be successfully analysed by gas--chromatography employing a flame-ionization detector, reaching a sensitivity of 2 micrograms/ml. The second approach led to the N-(2-chlorobenzoyl) derivative of lofemizole which was suitable for pharmacokinetic investigation using gas--liquid chromatography with electron-capture detection, and reaching a much higher sensitivity of 10 ng/ml of plasma. Recovery of the extraction, reproducibility and specificity were all satisfactory with both methods. Since the first method employing flame-ionization detection was suitable for pharmacokinetic investigations in animal species, this paper describes both methods on a comparative basis.

Anti-Inflammatory Agents↗
PubMed1983

Gas-liquid chromatographic evaluation of fenquizone in biological samples for pharmacokinetic investigations.

Extractive alkylation was carried out on fenquizone, a sulphonamide diuretic, in order to devise a suitable method for its determination in pharmacokinetic and bioavailability studies. After extraction as a tetramethyl derivative, fenquizone was evaluated by gas-liquid chromatography with a 63Ni electron-capture detector, which enables a limit of detection of 2 ng/ml of plasma or urine to be achieved. Linearity was verified in a range of 50- 10,000 pg for each injection with a fenquizone/internal standard ratio ranging from 4:1 to 1:4. Determination is very rapid, as one analysis only takes 5 min. The preliminary results of the pharmacokinetic study performed in a volunteer human subject after a single oral administration of the drug are presented in this paper in terms of the plasma levels and the cumulative urinary excretion.

Chromatography, Gas↗
PubMed1983

MR 714, a new aryloxypropionic non-steroidal antiinflammatory agent. Chemical and pharmacokinetic properties and preliminary pharmacotoxicological data.

2-(4-(2',4'-Difluorophenyl)-phenoxy)propionic acid (MR 714) is endowed with an interesting analgesic and antiinflammatory activity, while any remarkable gastro-ulcerogenic action is virtually absent. From a toxicological point of view, MR 714 orally administered to mice showed a LD50 of 848 mg/kg; an observation of general behaviour proved that the drug is free of any remarkable effect on general behaviour, food and water intake, or diuresis after single or repeated administration. An autoptic examination after single oral doses (25, 50, 100 and 200 mg/kg) or repeated oral doses (100 mg/kg/day over 5 days) did not show any adverse modification and also the Ames test didn't allow any mutagenic action to be detected. From a pharmacokinetic point of view, MR 714 given p.o. to rats was absorbed excellently and plasma levels showed a peak after 4-6 h, followed by a plateau lasting 24-36 h at a dose of 50 or 100 mg/kg and considerably less at a dosage of 25 mg/kg. This lower dose allowed a dominant half-life (t1/2) of plasma levels of 13 h to be determined. Excretion occurred only via the bile in conjugated form (acylglucuronide) which reverted easily into the parent drug. The resultant enterohepatic circulation contributes to a substantial maintenance of plasma levels and hence long-lasting activity. Among the organs examined, the uterus showed the highest ratio of organ/plasma concentration; this evidence points to a possible clinical application of MR 714 in the treatment of dysmenorrhoea. From a chemical point of view, the aryloxypropionic structure may be regarded as an interesting novelty in the field of structure-activity relationship studies on non-steroidal antiinflammatory agents.

Analgesics↗
PubMed1982

A new phthalidyl derivative of apovincaminic acid: (3 alpha,16 alpha)-eburnamenine-14 carboxylic acid phthalidyl ester (AF 698). A preliminary report on its chemical and pharmacological properties.

A new phthalidyl derivative of apovincamine, (3 alpha,16 alpha)-eburnamenine-14 carboxylic acid phthalidyl ester (AF 698), has been synthesized as hydrochloride. Its chemical and physical properties are described and its acute toxicity and vasodilator effect assayed in comparison with vincamine hydrochloride. AF 698 proved to possess lower acute toxicity than vincamine. Its peripheral vasodilator action, assayed on the perfused rat lower limb, was higher than that of vincamine. AF 698 was also more effective than vincamine in its central vasodilator activity electrocorticographically evaluated on the response of rabbits to selective cerebral ischaemia. The protective effect against the lethal action of hypobaric hypoxia in mice did not greatly differ between the two drugs.

Animals↗
PubMed1981

Simultaneous evaluation of apovincaminic acid esters and their metabolite apovincaminic acid by solvent partition and GLC in biological samples. Preliminary data with MR 711.

Apovincaminic acid (AVA) esters are eburnamenine derivatives with a vasodilating action that are mainly metabolized to AVA by enzymatic hydrolysis, in the rat in particular. In an organic solvent/water partition, AVA and AVA ester were quantitatively separated. AVA ester was then chemically hydrolysed into AVA. Unchanged AVA and AVA hydrolysed from its ester were separately methylated and quantitatively analysed by GLC. Using a flame ionisation detector, this method has a sensitivity of 20 ng making possible metabolic investigations to be carried out in vitro and in the urine and can be applied to any AVA ester. The method was applied in a preliminary investigation to MR 711, a methylene-methoxy-apovincaminic acid ester. When incubated in vitro with rat plasma, MR 711 was enzymatically converted into AVA. The urine of rats p.o. treated with 10 mg/kg of MR 711 contained AVA as the main metabolite.

Animals↗
PubMed1980

[Preliminary data on the pharmacokinetics of digoxin in pregnancy].

The pharmacokinetics of digoxin were investigated in 8 pregnant women (2-3 months before delivery), in three women 3 months after delivery, and in 3 non-pregnant women, after i.v. injection of 500 microgram. Digoxin was evaluated in serum with the radioimmunoassay method. In pregnant women C1 (concentration of digoxin in the first compartment) and V1 (volume of the first compartment) were higher and C2, K1-2, K2-1 (exchange constants) and Kel (elimination constant) were all lower than the values obtained in both post-partum and non-pregnant women. Our data lead us to think that the exchange (both uptake and release) between the first and second compartment is lowered in pregnancy.

Adult↗