[Determination of isosorbide-5-nitrate in human plasma by reversed-phase high performance liquid chromatography]

The method was established to determine the level of isosorbide-5-nitrate in human plasma by reversed-phase high performance liquid chromatography (RP-HPLC). The sample preparation was carried by alkalizing the plasma sample followed by extraction with dichloromethane. The HPLC analysis was performed under the conditions as follows: a mixture of an aqueous buffer (pH adjusted to 7.8 by 0. 03 mol/L ammonia water) and acetonitrile (80: 20, v/v) as mobile phase, paracetamol as the internal standard, and the detection at 230 nm. The linear range was 20 - 1 000 microg/L using the ratio of peak areas; the detection limit was 12 microg/L; the average recovery was (97.11 +/- 2.45)% - (104.34 +/- 2.17)%, the intra-day relative standard deviations (RSDs) were less than 2.52%, and inter-day RSDs were less than 5.21%.