阿奇霉素缓释干混悬剂的制备及其Beagle犬体内的药代动力学

Preparation of azithromycin extended release for suspension and study of pharmacokinetics in Beagle dogs

目的制备单剂量为2.0g的阿奇霉素缓释干混悬剂,建立Beagle犬血浆中阿奇霉素浓度的HPLC-MS-MS测定方法,并用于阿奇霉素缓释干混悬剂Beagle犬体内药代动力学研究及其缓释作用评价。方法采用湿法制粒包衣的方法制备阿奇霉素缓释干混悬剂,以罗红霉素为内标,血浆经正己烷-二氯甲烷-异丙醇(体积比20:10:1)提取,采用Diamonsil C18柱(150mm×4.6mm,5μm),以甲醇-0.450mmol·L-1乙酸铵水溶液(体积比85:15)为流动相,流速为0.6mL·min-1,进样量为10.0μL对样品进行分析。离子源为电喷雾电离源(Turbo Ionspray),正离子方式检测,扫描方式为多反应监测(MRM)。用于定量分析的离子反应分别为m/z749.5→m/z591.5(阿奇霉素)和m/z837.4→m/z158.2(罗红霉素),扫描时间为0.3s。结果阿奇霉素的线性范围为0.1～10mg·L-1,提取回收率为79.7%～85.2%,日内RSD值小于5.17%,日间RSD值小于13.5%。Beagle犬口服阿奇霉素受试制剂和参比制剂后的主要药动学参数:tmax分别为(1.75±0.530)和(0.750±0.610)h,ρmax分别为(6.84×103±1.69×103)和(8.73×103±2.59×103)μg·L-1,t1/2分别为(95±10.2)和(71.2±11.0)h,采用梯形法计算,AUC0～240分别为(3.05×105±6.27×104)和(2.86×105±3.89×104)μg·h·L-1,相对生物利用度为(106.8%±17.0)%。结论该法灵敏、准确,测定结果可靠,适用于阿奇霉素Beagle犬药代动力学研究;统计分析表明阿奇霉素缓释干混悬剂具有一定的缓释作用,可有效地抑制大剂量阿奇霉素的峰浓度。

Objective To develop an HPLC-MS-MS method for the determination of azithromycin in plasma and investigate its pharmacokinetic characteristics in Beagle dogs and evaluate the effect of azithromycin extended release suspension. Methods Azithromycin and internal standard (roxithromycin) were extracted from plasma by n-hexane-dichlormethane-isopropanol (V:V:V= 20:10:1), and then separated by Diamonsil C18 column with methanol–0.450 mmol·L-1 ammonium acetate( (V:V= 85:15) as mobile phase at flow rate of 0.6 mL·min-1, 10.0 μL sample was injected. Turbo Ionspray, position ion model and MRM (azithromycin m/z 749.5→ m/z 591.5; roxithromycin m/z 837.4 → m/z158.2) were used in the assay. Scan time was 0.3 s. Results The linear range was 0.1-10 mg·L-1, the extraction recovery was 79.7 %-85.2 %. The intra-day and inter-day precision were lower than 5.17% and 13.5%(n=6), respectively. The main pharmacokinetics parameters after a single oral dose of 2.0 g azithromycin test or reference preparation were as follow: tmax: (1.75±0.530) h and (0.750±0.610) h; ρmax: (6.84×103±1.69×103) μg·L-1 and (8.73×103±2.59×103)μg·L-1; t1/2: (95±10.2) h and (71.2±11.0) h; AUC0-240(μg·h·L-1): (3.05×105 ±6.27× 104) μg·h·L-1 and (2.86×105±3.89 ×104) μg·h·L-1. The relative bioavailability (F) was 106.8%±17.0%. Conclusion The method is sensitive, accurate and simple. It can be used for the pharmacokinetic studies of azithromycin in Beagle dogs. It is showed that there is sustained release characteristics for azithromycin extended release suspension.