Assay for the quinocarmycin analog DX-52-1 in human plasma using high-performance liquid chromatography with
J G Supko1, J R Soglia, R V Nair
1Division of Hematology-Oncology, Massachusetts General Hospital and Harvard Medical School, Boston 02114, USA.
Abstract:
The hydrocyanated derivative of the antitumor antibiotic quinocarmycin, DX-52-1 (I), exhibits impressive activity against human melanoma xenograft models in vivo. Phase I clinical trials to evaluate this compound as an antineoplastic agent have been initiated by the US National Cancer Institute. We have developed an HPLC assay for the determination of I in human plasma involving automated column switching and UV detection at 210 nm. The preparation of samples for chromatographic analysis entails the preliminary removal of plasma proteins by precipitation with acetonitrile, acidifying the clear supernatant to pH 4.5, then extracting twice with tert.-butyl methyl ether to recover the drug. A heart-cutting procedure employing two HPLC columns with contrasting retention characteristics under isocratic reversed-phase conditions was used to achieve the selectivity required for low wavelength UV detection of the analyte. The sample extract was initially loaded onto a column packed with a cyanopropyl stationary phase. During the predetermined time interval that I eluted from this column, a fully automated six-position switching valve was used to direct the effluent onto an octadecylsilane analytical column. The assay has been thoroughly validated with regard to linearity, inter- and intra-day accuracy and precision, recovery, selectivity and specificity. Using a sample volume of 1.0 ml, the lowest concentration of I quantified with acceptable day-to-day reproducibility was found to be 2.56 ng/ml (R.S.D. 18.9%, n=21, 4 months). This proved to be sufficiently sensitive for pharmacokinetic drug level monitoring in cancer patients treated with a 6-h continuous intravenous infusion of I, even at the starting dose of 3 mg/m2. The successful performance and reliability of the assay has been demonstrated through extensive application to the routine analysis of plasma specimens acquired during a phase I clinical trial of the drug.
Insights
A new HPLC method accurately measures DX-52-1, an anticancer drug, in patient plasma. This assay is crucial for monitoring drug levels during clinical trials for melanoma treatment.
Area of Science:
- Analytical Chemistry
- Pharmacology
- Oncology
Background:
- Quinocarmycin derivative DX-52-1 shows significant antitumor activity.
- Phase I clinical trials are underway to assess DX-52-1 as an antineoplastic agent.
- Accurate quantification of DX-52-1 in human plasma is essential for pharmacokinetic studies.
Purpose of the Study:
- To develop and validate a sensitive High-Performance Liquid Chromatography (HPLC) assay for DX-52-1 determination in human plasma.
- To enable reliable drug level monitoring in cancer patients during clinical trials.
Main Methods:
- Sample preparation involved protein precipitation with acetonitrile and liquid-liquid extraction.
- An automated column-switching HPLC system with two columns (cyanopropyl and octadecylsilane) was employed.
- UV detection at 210 nm was utilized for quantification.
Main Results:
- The validated HPLC assay demonstrated linearity, accuracy, precision, and specificity.
- The assay achieved a lower limit of quantification of 2.56 ng/ml with acceptable reproducibility.
- The method proved sufficiently sensitive for pharmacokinetic monitoring during Phase I trials.
Conclusions:
- A robust and sensitive HPLC assay for DX-52-1 in human plasma has been successfully developed and validated.
- This assay is suitable for routine analysis and pharmacokinetic drug level monitoring in cancer patients.
- The assay supports ongoing Phase I clinical trials of DX-52-1.
