Determination of Caffeine Plasma Concentration of Pemature Infant by HPLC

OBJECTIVE To establish HPLC determination method for the caffeine plasma concentration of premature infant. METHODS Chromatographic column was Insertil ODS-3(250 mm×4.6 mm, 5 μm) column with mobile phase consisted of methanol-water(28:72). Flow rate was set at 1 mL·min^-1 with column temperature of 30℃ and detection wavelength was 274 nm. Injection volume was 20 μL. RESULTS The calibration range of caffeine was 2.5-60 mg·L^-1 (r²=0.999 9, n=9). Detection limit was 0.125 mg·L^-1. The average recoveries of extraction and method were 82.5%-89.7% and 97.2%-103.0%. RSDs of intra-day and inter-day were<10%. Caffeine valley concentration of five infants randomly selected with loading-dose were (15.8±2.1)mg·L^-1, while in other five infant were (24.3±4.6)mg·L^-1 after caffeine administration for 7 d. All the results were within methodological linear limitation. CONCLUSION The method is rapid, simple and accurate to be used for plasma concentration monitoring of caffeine.