Determination of dihydrotanshinone I,cryptotanshinone,tanshinone I and tanshinone II_A in tanshinone ear drops by HPLC

OBJECTIVE A quantitative method was developed for the determination of dihydrotanshinone Ⅰ, cryptotanshinone, tanshinone Ⅰ and tanshinone Ⅱ A in tanshinone ear drops by HPLC. METHODS Column Intersil C 18 was used. The mobile phase was composed of acetonitrile - 10% acetonitrile with gradient eluation. The flow rate was 1.6 mL·min -1 with the wavelength at 254 nm. RESULTS The number of theoretical plates calculated by dihydrotanshinone Ⅰ, cryptotanshinone, tanshinoneⅠand tanshinoneⅡ A peak were 3?310, 4?278, 3?624 and 20?677 respectively. The average recoveries of dihydrotanshinone Ⅰ, cryptotanshinone, tanshinoneⅠ, tanshinone Ⅱ A were 101.3% (RSD=2.2%), 97.2% (RSD=2.2%), 102.1% (RSD=3.0%) and 99.5% (RSD=1.9%) respectively. The detection limits of dihydrotanshinone Ⅰ, cryptotanshinone, tanshinone Ⅰ and tanshinone Ⅱ A were about 0.6, 0.9, 0.6 and 0.3 μg·mL -1 respectively. CONCLUSION The method was sensitive, rapid and accurate.