LC-MS/MS method for the determination of rosiglitazone on rat dried blood spots and rat urine: Application to pharmacokinetics.

A bioanalytical method for the quantification of rosiglitazone on rat dried blood spots (DBS) and rat urine using liquid chromatography, electrospray ionization coupled with tandem mass spectrometry (LC-ESI-MS/MS) was developed and validated. The chromatographic separation was achieved on a Nova-Pak C18 Column (150 mm × 4.6 mm i.d., 4 μm), using 30 mM ammonium acetate (pH 4.0 adjusted with acetic acid) and acetonitrile (75:25, v/v) as a mobile phase at ambient temperature. LC-MS detection was performed with selected ion monitoring using target ions at m/z 358 and m/z 356 for rosiglitazone and pioglitazone respectively. The calibration curve showed a good linearity in the concentration range of 0.05-100 ng/mL. The effect of hematocrit, blood volume and punch location for DBS samples was studied. The mean recoveries of rosiglitazone from DBS and urine were 93.30% and 92.49% respectively. The intra and inter-day precisions of RSD were less than 4.82% in DBS as well as urine. The limit of detections and quantifications were 0.015 and 0.052 ng/mL in DBS and 0.023 and 0.075 ng/mL in urine samples respectively. The method was validated as per FDA guidelines and successfully applied to a pharmacokinetic study of rosiglitazone in rats.