Abstract: A high performance liquid chromatography method with gradient elution was established for simultaneous determination of anti-dandruff agent salicylic acid,pyrithione zinc,ketoconazole,climbazole and octopirox in shampoo formulations.A C₁₈ column was used as stationary phase,and mixture containing acetonitrile-methanol aqueous solution (0.01 mol/L KH₂PO₄ and 0.5 mmol/L EDTA-2Na,pH adjusted to 4 with H₃PO₄) eluted by gradient was used as mobile phase in the HPLC at the wavelength of 230 nm.Operating temperature was 35 ℃.Injection volume was 5 μL.The linearity range of salicylic acid,pyrithione zinc,ketoconazole and climbazole is 10~200 mg/L.The linearity range of octopirox is 20~400 mg/L.The detection limits for salicylic acid,pyrithione zinc,ketoconazole,climbazole and octopirox are 0.26,0.53,0.26,0.26 and 2.0 mg/L respectively.The spiked recovery of matrix for salicylic acid,pyrithione zinc,ketoconazole,climbazole and octopirox varies from 96.04% to 98.42%.Among test results of 83 shampoo samples from market,pyrithione zinc appears in 57 samples;octopirox appears in 18 samples;salicylic acid appears in 7 samples;climbazole appears in 3 samples;banned substance ketoconazole is not detected.The contents of anti-dandruff agents in all samples meet the relevant standard requirements.

Key words: shampoo, anti-dandruff agent, high performance liquid chromatography