目的：研究氯化镁缓释片的释放度和相对生物利用度。方法：采用原子吸收分光光度法测定氯化镁缓释片和进口氯化镁缓释片（ＳｌｏｗＭａｇ）的体内外释放浓度，计算体内外参数，考察氯化镁缓释片的缓释效果，并与ＳｌｏｗＭａｇ进行对照。结果：氯化镁缓释片体外释放符合Ｈｉｇｕｃｈｉ模型；氯化镁缓释片和ＳｌｏｗＭａｇ的药时曲线可用二室模型拟合，ｔｍａｘ分别为３７９６７ｈ和２１３６７ｈ，ｃｍａｘ分别为７８２５７μｇ·ｍｌ－１和８０２５４μｇ·ｍｌ－１，ＡＵＣ分别为５６５１７２，３４１９７１μｇ·ｈ·ｍｌ－１。结论：氯化镁缓释片对ＳｌｏｗＭａｇ的相对生物利用度为１６５２６％，二者为生物不等效制剂 Objective: To study the release and relative bioavailability of magnesium chloride sustained-release tablets. Methods: Atomic absorption spectrophotometry was used to determine the in vitro and in vivo released concentrations of MgCl 2 and MgO in vitro and in vivo. The in vitro and in vivo parameters were calculated and the sustained-release effect of MgCl 2 sustained- For comparison. Results: The release of magnesium chloride sustained-release tablets in vitro was in accordance with Higuchi model. The curves of drug-induced curves of magnesium chloride sustained-release tablets and Slow-Mag were fitted by two-compartment model with tmax of 37967h and 21367h, ml-1 and 80254μg · ml-1 respectively, with AUC of 565172 and 341971μg · h · ml-1, respectively. Conclusion: The relative bioavailability of magnesium chloride to SlowMag was 16526%, both bioequivalents