Selective solid-phase extraction of basic drugs by C8-silica. Discussion of possible interactions

Marko, Vladimir; Šoltés, Ladislav; Novak, I. I.

doi:10.1016/0731-7085(90)80041-m

Cited by 18 publications

(4 citation statements)

References 13 publications

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“…Even for batches of sorbents of the same manufacturer varying recoveries have been observed [42,45,46]. This between-manufacturer and between-batch variation for SPE sorbents is probably comparable with the variations observed for HPLC columns [47-491 as the synthesis of the two types of bonded silica is similar and both use the distribution of the analyte between solid and liquid phases.…”

Section: Reproducibility Of Spesupporting

confidence: 50%

Analyte isolation by solid phase extraction (SPE) on silica-bonded phases: Classification and recommended practices (Technical Report)

Moors¹,

Massart²,

McDowall³

1994

Pure and Applied Chemistry

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Section: Reproducibility Of Spesupporting

confidence: 50%

Analyte isolation by solid phase extraction (SPE) on silica-bonded phases: Classification and recommended practices (Technical Report)

Moors¹,

Massart²,

McDowall³

1994

Pure and Applied Chemistry

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“…Prior to subsequent elution/ displacement of the trapped (basic) analytes, eg by methanol, inclusion of the sorbent washing with acetonitrile has proved to be highly advantageous (Šoltés, 1992a, 1992bŠoltés and Sébille, 1997). Similar observations were reported in the case of bioanalysis of several other basic drugs (Šoltés et al, 1983Marko et al, 1985Marko et al, , 1990aMarko et al, , 1990b. Similar observations were reported in the case of bioanalysis of several other basic drugs (Šoltés et al, 1983Marko et al, 1985Marko et al, , 1990aMarko et al, , 1990b.…”

Section: Chromatography In Drug Bioanalysissupporting

confidence: 59%

Extraction and chromatographic separation methods in pharmacokinetic studies of Stobadine�?an indole-related antioxidant and free-radical scavenger

Šoltés

Bezek

Ujházy

et al. 2000

Biomed. Chromatogr.

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This overview provides comprehensive information on the most relevant results of Stobadine preclinical disposition studies. In order to investigate pharmacokinetic processes of the drug in rats, dogs and in human volunteers, several bioanalytical assays based on radiometric, spectrofluorometric, as well as chromatographic determination methods were developed and implemented. In small laboratory animals, the drug absorption, distribution, metabolism and elimination were investigated by administering 3H-labeled Stobadine. Spectrofluorometry was used alternatively for the determination of cold/unlabeled Stobadine in extracts of biomaterials sampled from larger animal species. The chromatographic separation methods proved, however, to be the most advantageous for determining details of the drug disposition and fate in the body.

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“…The extraction included the acetonitrile wash-out step and methanolic eluation. The elution profiles of basic drugs, such as stobadine, obtained with solid-phase extraction performed on C I8 silanized silica indicate the presence of multiple types of interactions between the sorbent and the basic drug, ranging from hydrophobic interactions to solute-sorbent ionic forces (19,20).…”

Section: Discussionmentioning

confidence: 99%

Overview of stobadine bioanalysis: evaluation and application in pharmacokinetics

Bauerová

1999

Eur. J. Drug Metab. Pharmacokinet.

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Besides its many pharmacodynamic actions, the pyridoindole stobadine was found to exert antioxidant activity and thus possesses the potential to protect various tissues against oxidative stress. This overview is focussed on both the evaluation of the chemical procedures used in the bioassay of stobadine and its metabolites and on the comparison of their quality in the light of applicability for preclinical and clinical pharmacokinetic experiments. All methods and applications were performed at the Institute of Experimental Pharmacology, SASc in Bratislava, Slovakia. In pharmacokinetic and toxicokinetic studies, [3H]-labeled stobadine dihydrochloride was administered intravenously or orally to rats in single and repeated doses. Liquid-liquid extraction was used for selective isolation of stobadine and its metabolites from biological matrix, followed by liquid scintillation quantification. A TLRC method was developed both to check the radiochemical purity of [3H]-stobadine and to quantify the labeled drug in rat plasma. A spectrofluorometric approach was used for determination of stobadine in dog serum and urine after its administration in the form of either the dihydrochloride or the dipalmitate. The method allowed us to perform a bioavailability study and a long-term toxicological study. The HPLC method with a limit of detection of 10 ng/ml of plasma proved suitable for calculating the compartmental pharmacokinetic parameters of both salt forms of stobadine administered to dog and man. This method was based on solid-phase extraction procedure by using Separcol SI C18 cartridges. In a GC method, the combination of capillary column separation and nitrogen-specific detection permitted the assay of serum stobadine concentrations as low as 5 ng/ml. The detection limit of the GC/MS method was 1 ng/ml of plasma or of phosphate buffer saline. This method was used for a bioequivalence study of two stobadine dipalmitate dosage forms and for a transdermal penetration study of stobadine acyl derivatives. All the developed assays proved to be appropriate for low-concentration determination of stobadine in a wide range of pharmacokinetic studies.

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Selective solid-phase extraction of basic drugs by C8-silica. Discussion of possible interactions

Cited by 18 publications

References 13 publications

Analyte isolation by solid phase extraction (SPE) on silica-bonded phases: Classification and recommended practices (Technical Report)

Analyte isolation by solid phase extraction (SPE) on silica-bonded phases: Classification and recommended practices (Technical Report)

Extraction and chromatographic separation methods in pharmacokinetic studies of Stobadine�?an indole-related antioxidant and free-radical scavenger

Overview of stobadine bioanalysis: evaluation and application in pharmacokinetics

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