Bioanalysis of (E)-5-(2-bromovinyl)-2'-deoxyuridine

Development and validation of a bioanalytical assay for (E)-5-(2-bromovinyl)-2'deoxyuridine in plasma by capillary zone electrophoresis

A capillary zone electrophoretic method for the quantification of (E)-5-(2-bromovinyl)-2'-deoxyuridine in plasma has been developed and validated. Separation was performed with a 25 mmol/l borate buffer, pH 9.0, after an initial rinsing step with sodium hydroxide. The rinsing step was necessary for reproducible analyses of aqueous samples and plasma extracts obtained by C18 solid-phase extraction after deproteination with perchloric acid. No interferences with plasma compounds were observed. The calibration graph was linear over the range of 30 to 3000 ng/ml using 5-fluorouracil as external standard. The limit of quantification was 24 ng/ml. The CZE method is fast, reproducible, linear and is therefore a good alternative for the already established HPLC methods.

Determination of (E)-5-(2-bromovinyl)-2'-deoxyuridine in plasma and urine by capillary electrophoresis

(E)-5-(2-Bromovinyl)-2'-deoxyuridine is an antiviral drug used for treatment of infections with Herpes simplex virus type 1 as well as Varicella zoster virus. Two fast methods for the determination of the drug and its metabolite in plasma and urine by capillary electrophoresis have been developed. The plasma method can be used for measurement of total as well as unbound drug and metabolite. Plasma and urine samples are prepared for measuring by liquid/liquid extraction resulting in a limit of quantification of 40 ng/ml for total and 10 ng/ml for free BVdU in plasma and 170 ng/ml in urine. Inter- as well as intra-day precision were found to be better than 10% and both methods have been used for drug monitoring of patients.

Manual and automated determination of 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl)uracil and its metabolite (E)-5-(2-bromovinyl)uracil in urine

This paper describes the determination of 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl)uracil in urine. The method involves sample clean-up by liquid-liquid extraction with ethyl acetate followed by high-performance liquid chromatographic (HPLC) analysis. The sample preparation may be performed either manually or automatically using a Zymark Py-robotic system. The chloro analog of the parent compound, CV-araU, is used as the internal standard. As low as 0.1 microgram of analyte per ml of urine can be measured. This sensitivity is adequate for pharmacokinetic studies but could be improved quite easily if necessary.

Inhibition of fluorouracil catabolism in cancer patients by the antiviral agent (E)-5-(2-bromovinyl)-2'-deoxyuridine

The thymidine analogue (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVdUrd), which is an antiviral agent effective against herpes simplex virus type 1 and varicella zoster virus, has also proved to be a potent inhibitor of dihydrouracil dehydrogenase, the major degrading enzyme of the anticancer drug fluorouracil (FUra). To evaluate the effect of BVdUrd on the pharmacokinetics of FUra in cancer patients, BVdUrd was administered orally at a daily dose of 250 mg (five patients) or 3 x 250 mg (five patients). FUra was infused at doses of 110-400 mg over 10 min. Blood and urine samples were collected regularly during a period of up to 50 h. BVdUrd was rapidly absorbed, peak plasma levels of 0.6-7.1 micrograms/ml being achieved after 1-2 h. Following a rapid decline, plasma BVdUrd levels remained higher than 10 ng/ml for up to 2 days after BVdUrd administration. The total body clearance of FUra was approximately 61/h and t1/2 markedly increased to 4-7 h. The mean urinary excretion of FUra was 50%. No differences in FUra kinetics were observed between patients receiving one or three oral doses of BVdUrd. We conclude that the concomitant use and subsequent interaction of FUra and the antiviral agent BVdUrd resulted in an impressive inhibition of FUra breakdown and marked increase of renal clearance. The findings indicate that the simultaneous use of FUra and drugs resembling this antiviral agent in patients may result in unexpected toxicity. Further experience with BVdUrd and new analogues might enable the development of new FUra treatment schedules and treatment designs e.g. combinations with leucovorin.

High-performance liquid chromatographic determination of 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl)uracil and its metabolite (E)-5-(2-bromovinyl)uracil in serum

A high-performance liquid chromatographic method was developed to assay 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl)uracil and its metabolite (E)-5-(2-bromovinyl)uracil in serum. The chloro analogue of the parent drug is used as internal standard. Human serum samples were assayed to establish the pharmacokinetic parameters. Acetonitrile, used as a protein precipitant, was evaporated to dryness and the residue, containing the analytes and internal reference, was dissolved in mobile phase prior to chromatographic analysis. The minimum quantifiable level was 0.02 micrograms of each analyte per ml of serum.

Chromatographic methods for the bioanalysis of antiviral agents

The present review has concentrated on chromatographic techniques for the quantitative determination of antiviral drugs in biological samples. Special attention has been paid to the elements of chromatographic assays that are essential to ensure selectivity, sensitivity, accuracy and precision of the various methods. Wherever possible, attempts have been made to determine the suitability of the methods for application to investigations in pharmacokinetics in man and experimental animals, biopharmaceutics, therapeutic drug monitoring, metabolism and pharmacology. Because of the serious consequences of infection from material contaminated with viruses, special consideration has been given to the handling of contaminated samples. It was convenient to divide the antiviral drugs for the purpose of this review into two groups, the nucleoside and the non-nucleoside antiviral drugs. The nucleosides discussed are vidarabine, cytarabine, ribavirin, riboxamide, acyclovir, ganciclovir, desciclovir, carbovir, 2',3'-dideoxyadenosine, 2',3'-dideoxycytidine, zidovudine, 2',3'-dideoxyinosine, 2',3'-didehydro-3'-deoxythymidine, idoxuridine, 5-(2-bromovinyl)-2'-deoxyuridine, 2'-fluoro-5-iodoaracytidine and 5-iodo-2'-deoxycytidine. The non-nucleoside antiviral drugs discussed are arildone, amantidine, rimantidine, moroxydine, enviroxime, foscarnet and ampligen.