A subnanogram API LC/MS/MS quantitation method for depsipeptide FR901228 and its preclinical pharmacokinetics.
A highly sensitive and specific atmospheric pressure ionization (API) liquid chromatographic-tandem mass spectrometric (LC/MS/MS) method for the quantitation of depsipeptide FR901228 (NSC-630176, FR), a naturally occurring antitumor agent, was developed and validated. FR was extracted from human or rat plasma along with the internal standard, t-Boc-Met-Leu-Phe (BMLP) with ethyl acetate. Components in the extract were separated on a 5-microm C8 Spherisorb 50 x 4.6 mm i.d. column by isocratic elution with methanol/acetonitrile/12 mM ammonium acetate (60:10:30, v/v/v). The liquid flow was passed through a presource splitter and 5% of the eluate was introduced into the API source. The components were analyzed in the multiple-reaction monitoring (MRM) mode to enhance specificity. Linear calibration curves were obtained in the range of 0.1-100.0 ng/ml with 0.5 ml human plasma and 0.5-100.0 ng/ml with 0.1 ml rat plasma. The limit of quantitation (LOQ) was 0.1 ng/ml using 0.5 ml human plasma and 0.5 ng/ml using 0.1 ml rat plasma. The overall within-day precision was below 12% in human plasma and below 7% in rat plasma; and the between-day precision was below 10.2% in human plasma and 7.2% in rat plasma. The accuracy at low, medium and high levels ranged from 99.3 to 111.7% in human plasma and 96.2-107.3% in rat plasma. The high sensitivity permitted pharmacokinetic study of FR in the rat at a single i.v. dose as low as 1 mg/kg. At this dose, plasma FR levels declined biexponentially with a mean terminal t(1/2) of 187.7 min (n = 6) and were detectable up to 24 h. After an oral dose at 5 mg/kg, plasma FR levels were highly erratic and yielded a mean bioavailability of 1.6% (n = 6). At a higher oral dose of 50 mg/kg, a mean bioavailability of 10.6% was obtained, both being estimated by a non-crossover method.
Li
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College of Pharmacy, and Comprehensive Cancer Center, The Ohio State University, Columbus 43210, USA.
Chan
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D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000493:pharmacokinetics*; D000903:Antibiotics, Antineoplastic / Q000032:analysis* / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002853:Chromatography, Liquid; D047630:Depsipeptides; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D010456:Peptides, Cyclic; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results
D000900:Anti-Bacterial Agents; D000903:Antibiotics, Antineoplastic; D047630:Depsipeptides; D010456:Peptides, Cyclic; C087123:romidepsin