目的 建立反相高效液相色譜法測定左卡尼汀片中已知雜質左卡尼汀雜質A。方法 色譜柱為Waters μBondapakTM NH2（300 mm×3.9 mm，10 μm）；流動相為0.05 mol/L磷酸二氫鉀溶液（用稀磷酸調節(jié)pH值4.0）–乙腈（35∶65）；體積流量1.0 mL/min；檢測波長為205 nm；進樣量20 μL；柱溫為30 ℃，外標法計算。結果 片劑中左卡尼汀雜質A與左卡尼汀能夠完全分離，空白輔料不干擾測定，左卡尼汀雜質A在5.01～75.15 μg/mL線性關系良好（r＝1.000）。左卡尼汀雜質A平均回收率為100.8%（RSD＝1.16%，n＝9）。結論 經方法學考察，左卡尼汀片中已知雜質左卡尼汀雜質A測定方法的專屬性強，準確可靠，易于操作。左卡尼汀片中已知雜質左卡尼汀雜質A的量較低并且穩(wěn)定。

Objective To develop a RP-HPLC method to determine levocarnitine impurity A in Levocarnitine Tablets. Methods The chromatographic conditions included Water μBondapakTM NH2 column (300 mm × 3.9 mm, 10 μm) and 0.05 mol/L KH2PO4 (adjusted to pH 4.0 with diluted phosphoric acid)-acetonitrile (35∶65) as the mobile phase at a flow rate of 1.0 mL/min, detected at 205 nm, injection volume was 20 μL, and the column temperature was 30 ℃, using external standard method to calculate. Results Impurity A and levocarnitine could be completely separated, and blank recipients did not influence the determination. There was a good linearity in the range of 5.01 — 75.15 μg/mL (r = 1.000). The average recovery of levocarnitine impurity A was 100.8% (RSD = 1.16%, n = 9). Conclusion The established method is high selective, simple, and accurate. Amount of levocarnitine impurity A is little and stable in Levocarnitine Tablets.