RPHPLC METHOD FOR DETERMINATION OF ISORHYNCHOPHYLLINE IN PLASMA AND ITS PHARMACOKINETICS IN RABBI

A reversed phase HPLC method for determination of isorhnchophylline (IRHY) in rabbit plasma was developed. A Shimadzu LC10A liquid chromatograph equipped with a Shimadzu SPD10A multiwavelength detector and a Chromatopac LC10A data processor were used. The analytical column was a 46 mm×150 mm CLCODS. The mobile phase was a mixture of methanolwater (95∶5), the flow rate was 1 ml·min-1. Detection was performed at UV 254 nm. The calibration curve was linear in the range from 0016 to 16 μg·ml-1 with γ=09990. The lowest detection limit was 0016 μg·ml-1. The precision and accuracy of withinday and daytoday ranged from 38% to 69%. The recoveries were 805% to 851%. The drug concentrtiontime curves of IRHY in rabbits after iv of 2 mg·kg-1 and 5 mg·kg-1 were shown to fit a twocompartment open model with halftimes of 132±06 h and 125±009 h respectively. The absorption was fast after intraduodenal administration of IRHY (2 mg·kg-1 and 5 mg·kg-1) to rabbits with halftimes of 175±018 h and 126±020 h, respectively. The bioavailability of IRHY was about 424% to 694%. The results showed that the method was simple and fast. The absorption and elimination were fast atfer intraduodenal administration or iv of IRHY to rabbits.