High-performance liquid chromatographic analysis of N,N',N"-triethylenethiophosphoramide in human plasma

Separation methods for alkylating antineoplastic compounds

The separating method for alkylating neoplastic compounds were reviewed based on the classification of the Merck Index (12th Edition). Each section, whenever available or relevant, was subdivided according to the following approach: stability studies, extraction methods, gas chromatography, high-performance liquid chromatography and capillary electrophoresis. At the end of each chapter a separate table summarizing the main characteristics of the separating method were established. In particular LODs and/or LOQs were expressed as quantity to facilitate comparison between methods. This review highlights the problems to measure trace levels of these compounds into biological fluids with respect to their instability, adsorption to glass and plastic or derivatization requirements. Over the last decades, HPLC seems to be more popular than GC for separating the alkylating agents. The development of narrow- or microbore LC coupled to MS is certainly the way to further improve both separation and sensitivity obtained in the different papers surveyed for this review.

High-dose thiotepa and melphalan with hemopoietic progenitor support following induction therapy with epirubicin-paclitaxel-containing regimens in metastatic breast cancer (MBC)

BACKGROUND

Preliminary data from phase III randomized studies have failed to show benefit of HDC given as consolidation after anthracycline and alkylating-based chemotherapy in metastatic breast cancer (MBC). Moderate activity of induction regimens and selection of chemoresistant clones are among the possible reasons for these disappointing results. We therefore have designed a phase II study where high-dose alkylating agents are given as consolidation after an induction treatment including the most active agents (epirubicin and paclitaxel) without alkylating agents.

PATIENTS AND METHODS

Patients with MBC not previously treated with chemotherapy for metastatic disease were eligible. After six courses of epirubicin-paclitaxel +/- gemcitabine patients received a course of thiotepa 600 mg/m2 + melphalan 160 mg/m2 with hemopoietic support. Pharmacokinetic parameters of thiotepa and melphalan were measured and related to treatment outcomes. The L-VEF of the patients was monitored before and after treatment.

RESULTS

Forty-eight patients have been treated. Before HDC 14 patients were in CR, and 34 in PR. A median of 6.92 x 10(6) (range 1.53-16.6) CD34+ cells/kg were reinfused after HDC. Median days (range) to neutrophils > 0.5 x 10(9)/l and platelets > 20,000 x 10(9)/l were 9.5 (9-33) and 10 days (9-32), respectively. Symptomatic CHF was observed in two patients (4.1%). Cmax and AUC of thiotepa showed a linear relationship with time to progression (TTP) and overall survival (OS): r2 = 0.6. After HDC the conversion rate from PR to CR was 44.1%. At five years progression-free and overall survival rates are 37.5% and 65%, respectively. A treatment-related death was observed.

CONCLUSIONS

High-dose thiotepa and melphalan after an epirubicin-paclitaxel-containing treatment is feasible, devoid of significant cardiotoxicity and very active. Pharmacokinetic parameters of high-dose thiotepa might be linked to treatment outcome.

Chemistry, pharmacology and pharmacokinetics of N,N',N" -triethylenethiophosphoramide (ThioTEPA)

N,N',N" -triethylenethiophosphoramide (thioTEPA) is a trifunctional alkylating agent with a broad spectrum of antitumour activity developed in the 1950s. The drug is now experiencing renewed interest as it appears to be one of the most effective anticancer drugs in high dose regimens. Despite many years of experience with thioTEPA, pharmacologic data are incomplete and controversy remains with respect to the dose-dependent pharmacokinetics of thioTEPA. In recent years greater insight has been obtained into the metabolism of thioTEPA, but there is still a gap between the total urinary excretion of thioTEPA and metabolites and the alkylating activity. In vivo and in vitro studies show that alkylation of DNA by thioTEPA can follow two pathways, but it remains unclear which pathway represents the precise mechanism of action. The currently available sensitive analytical methods for thioTEPA and its metabolites can be used to elucidate the many questions that still exist even so many years after its introduction. An overview is given of the chemistry, pharmacology, clinical use and toxicity of thioTEPA as well as its pharmacokinetics and analytical methods for thioTEPA and its metabolites.

Determination of N,N',N"-triethylenthiophosphoramide in biological samples using capillary gas chromatography

A sensitive assay for the determination of N,N',N"-triethylenthiophosphoramide (thioTEPA) in microvolumes of human plasma and urine has been developed. ThioTEPA was analysed using gas chromatography with selective nitrogen-phosphorus detection, after extraction with ethyl acetate from the biological matrix. Diphenylamine is the internal standard. The limit of quantitation was 0.1 ng/ml, using only 100 microl of sample; recoveries ranged between 85 and 100% and both accuracy and precision were less than 10%. Using a flame ionisation nitrogen-phosphorus detector, the assay was not linear over the concentration range of 2-1000 ng/ml for plasma and 10-1000 ng/ml for urine. Linearity was accomplished in the range of 1-1000 ng/ml for plasma and urine when a thermionic nitrogen/phosphorous detector was used. The stability of thioTEPA in plasma proved to be satisfactory over a period of 3 months, when kept at -20 degrees C, whereas it was stable in urine for at least 1 month at -80 degrees C. ThioTEPA plasma concentrations of two patients treated with thioTEPA are presented demonstrating the applicability of the assay.