Determination of busulfan in human plasma by gas chromatography with electron-capture detection

Improved assay for determination of busulfan by liquid chromatography using postcolumn photolysis

A highly sensitive and time-reduced HPLC assay for the quantitative analysis of busulfan in plasma and aqueous samples is described. The assay is based on a precolumn derivatization of busulfan to 1,4-diiodobutane and UV-detection of iodide ions generated by a postcolumn photochemical dissociation of the derivative. The extraction and derivatization were carried out in a one-pot reaction without any solid phase extraction and is therefore suitable for high throughput analysis. Quantification was performed by using 1,5-pentanediol-bis-(methanesulfonate), a homologue of busulfan, as an internal standard. Linearity was demonstrated for concentrations from 50 to 10,000ng/ml. The limit of detection was found at 10ng/ml. Precision is indicated by an intra-day variety of 2.81% and by an inter-day variety of 6.61% for aqueous samples, 2.93 and 5.76% for plasma samples, respectively. The recovery of busulfan in plasma was more than 95%. No coelution with metabolites of busulfan or other drugs used in cancer therapy was found. The method was generated for measurements of busulfan in aqueous or plasma samples and applied in therapeutic drug monitoring of busulfan.

Population pharmacokinetic analysis resulting in a tool for dose individualization of busulphan in bone marrow transplantation recipients

The aims of the present study were (1) to investigate and quantify the pharmacokinetics, including inter-occasion variability and covariate relationships, of busulphan in BMT patients and (2) to develop a user-friendly initial dosing and therapeutic drug monitoring (TDM) strategy for the treatment of those patients with busulphan. The pharmacokinetics of busulphan was studied in 64 adults and 12 children who received busulphan (1 mg/kg) four times daily for 4 days. A one-compartment model with first order absorption and a lag time was sufficient in describing the concentration-time profile. Oral clearance (CL/F) was found to be correlated to weight (+1.2%/kg), ALT (-13%/microcat/l) and concomitant phenytoin treatment (+21%). CL/F and the volume of distribution (V/F) were estimated to 9.23 l/h and 39.3 l, respectively, in a typical individual. Inter-occasion variability (9.4%) in CL/F was estimated to be less than inter-individual variability (28%), a prerequisite for the value of TDM. Bayesian CL/F estimates based on three samples were in good accordance with those based on all samples. The final population model was implemented into the program Excel. The resulting flexible and easy to use dosing program might be used for both initial and, requiring only three plasma samples, maintenance dose individualization of busulphan therapy.

Chromatographic analysis of anticancer drugs

The present review on the methods for the analysis of anticancer drugs should be seen as an addition to the excellent work of Eksborg and Ehrsson published half a decade ago in this journal (Vol. 340, p.31). The style and format have been followed closely, with the focus again on chromatographic techniques. We felt it important to add a list of compound (group) structures as a service to the reader. Methods have been reviewed for alkylating agents, platinum compounds, antitumour antibiotics, antimetabolites, alkaloids, suramin, 1-hydroxy-3-amino-propylidene-1,1-bisphosphonate and tamoxifen.