title: Determination of GTI-2040, a novel antisense oligonucleotide, in human plasma by using HPLC combined with solid phase and liquid-liquid extractions.
abstract: GTI-2040 is a 20-mer phosphorothioate oligonucleotide complementary to the mRNA of the R2 subunit of ribonucleotide reductase (RNR). It is under clinical development as an anti-cancer agent. A reverse phase high-performance liquid chromatograph (HPLC) method was established for the quantitative analysis of GTI-2040 in human plasma. Plasma samples were prepared with an initial solid-phase extraction (SPE) followed by a liquid-liquid extraction step. HPLC analysis was performed with a gradient system on a Waters XTerraMS C18 column. The mobile phase consisted of acetonitrile-tetrabutyl ammonium hydrogen sulfate (TBAS) buffer (pH 9.0, 20 mM) at a flow rate of 1.0 ml/min, and the detector was set at a wavelength of 260 nm. A cationic pairing reagent, tetrabutyl ammonium hydrogen sulfate was added during plasma sample clean-up with solid-phase extraction, resulting in significant improvement in extraction recovery. In addition, TBAS addition to the mobile phase improved the peak symmetry of GTI-2040. This method was successfully used in the analysis of GTI-2040 in clinical plasma samples.
authors.affiliation: Department of Experimental Therapeutics, Ontario Cancer Institute, Ont. Canada.
authors.forename: Wenjiang
authors.initials: W
authors.lastname: Zhang
authors.forename: Natasha
authors.initials: N
authors.lastname: Leighl
authors.forename: Diane
authors.initials: D
authors.lastname: Zawisza
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Moore
authors.forename: Eric X
authors.initials: EX
authors.lastname: Chen
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D009838:Oligodeoxyribonucleotides; D016376:Oligonucleotides, Antisense / Q000097:blood* / Q000493:pharmacokinetics; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet
chemical_list: D009838:Oligodeoxyribonucleotides; D016376:Oligonucleotides, Antisense; C464617:GTI2040