藻红可见吸收光谱法测定药片中的盐酸美西律

目的 建立快速测定药物中盐酸美西律的高灵敏可见吸收光谱法。方法 在酸性Tris-HCl介质中，利用藻红与盐酸美西律的显色反应生成具有2个较强正吸收峰的离子缔合物，采用单波长和双波长可见吸收光谱法研究药物中盐酸美西律的定量检测方法，测定波长为477 nm和548 nm。结果 在pH 4.69的酸性溶液中，藻红与盐酸美西律通过静电引力相互作用生成二元离子缔合物，使吸收曲线出现2个较强的正吸收峰，分别位于477 nm和548 nm，盐酸美西律在0.03~4.30 mg·L^-1的质量浓度与吸光度（A₄₇₇和A₅₄₈）呈好的线性关系，服从朗伯-比尔定律，单波长法的表观摩尔吸光系数（к）为5.56×10⁴ L·mol^-1·cm^-1（477 nm）和5.04×10⁴ L·mol^-1·cm^-1（548 nm），检出限分别为0.024 mg·L^-1（477 nm）和0.020 mg·L^-1（548 nm）。双波长法的表观摩尔吸光系数（к）达1.05×10⁵ L·mol^-1·cm^-1，检出限为0.011 mg·L^-1，回收率为98.4%~102%，相对标准偏差为2.2%~2.6%。结论 单波长或双波长可见吸收光谱法均可用于药物中盐酸美西律的定量测定，且简便、快速、灵敏。

Determination of Mexiletine Hydrochloride in Tablets by Visible Absorption Spectrometry with Erythrosin

OBJECTIVE To establish a novel high sensitivity visible absorption spectrometry for rapid determination of mexiletine hydrochloride in drugs. METHODS In acidic Tris-HCl medium, the color reaction occurred between erythrosin with mexiletine hydrochloride to form ion association complex with two strong positive absorption peaks, the single-wavelength visible absorption spectroscopy and double-wavelength visible absorption spectroscopy were used to study the quantitative detection method of mexiletine hydrochloride in the drugs. The detection wavelength were 477 nm and 548 nm. RESULTS In a acidic solution of pH 4.69, erythrosin interacts with mexiletine hydrochloride through electrostatic attraction to form a binary ion association complex, which led to appear two strong positive absorbing peaks on absorption curve and their positive absorbing peaks were located at 477 nm and 548 nm, respectively. The absorbance(A₄₇₇ and A₅₄₈) had a good linear relationship with the mass concentration of mexiletine hydrochloride in the range of 0.03 to 4.30 mg·L^-1, they obeyed Lambert-Beer's law. The apparent molar absorbance coefficient(κ) of the single-wavelength method were 5.56×10⁴ L·mol^-1·cm^-1(477 nm) and 5.04×10⁴ L·mol^-1·cm^-1(548 nm), their detection limits were 0.024 mg·L^-1(477 nm) and 0.020 mg·L^-1(548 nm), respectively. The apparent molar absorption coefficient(κ) of the double-wavelength method could be up to 1.05×10⁵ L·mol^-1·cm^-1, its detection limit was 0.011 mg·L^-1, the recovery rate was 98.4%-102%, and the relative standard deviation was 2.2%-2.6%. CONCLUSION The single-wavelength visible absorption spectrometry or double-wavelength visible absorption spectrometry can be used for the quantitative determination of mexiletine hydrochloride in drugs, they are simple, fast and sensitive.