Plasma Concentrations,Pharmacokinetics and Urinary Excretion of Gatifloxacin after Single Intravenous Injection in Buffalo Calves

The pharmacokinetics and urinary excretion of gatifloxacin were investigated after a single intravenous injection of 4 mg/kg body weight in buffalo calves. The therapeutic plasma drug concentration was maintained for up to 12 h. Gatifloxacin rapidly distributed from blood to tissue compartments, which was evident from the high values of the distribution rate constant, α₁ (11.1 ± 1.06 h⁻¹) and the rate constant of transfer of drug from central to peripheral compartment, k ₁₂ (6.29 ± 0.46 h⁻¹). The area under the plasma drug concentration–time curve and apparent volume of distribution were 17.1 ± 0.63 (μg.h)/ml and 3.56 ± 0.95 L/kg, respectively. The elimination half-life (t _{1/2 β}), total body clearance (Cl_B) and the ratio of drug present in tissues and plasma (T/P) were 10.4 ± 2.47 h, 235.1 ± 8.47 ml/(kg.h) and 10.1 ± 2.25, respectively. About 19.7% of the administered drug was excreted in urine within 24 h. A satisfactory intravenous dosage regimen for gatifloxacin in buffalo calves would be 5.3 mg/kg at 24 h intervals. Abbreviations for pharmacokinetic parameters are given in the footnote of Table I     

液相色谱-串联质谱法测定牛肉中加替沙星残留量的研究

建立牛肉中加替沙星残留量检测的液相色谱-串联质谱(liquid chromatography-tandem mass spectrometry, LC-MS/MS)方法。牛肉样品经80%(V/V)乙腈溶液提取, Prime HLB固相萃取柱净化。采用0.1%甲酸(V/V)-甲醇溶液(A)和0.1%甲酸(V/V)-水溶液(B)进行梯度洗脱, 电喷雾离子源正离子扫描模式(ESI+),多反应监测(MRM),内标法定量。结果表明,加替沙星进样浓度在1～50 ng/mL范围内与峰面积呈良好的线性关系(r₂^＝0.999);方法检出限和定量限分别为1.0和2.0 μg/kg;在2.0、4.0、20 μg/kg 3个添加水平上,回收率在64.2%～113.4%之间,相对标准偏差为5.0%～9.7%(n=6)。本方法快速、准确、灵敏,适用于牛肉中加替沙星残留量检测。     

The effects of moxifloxacin ophthalmic solution 0.5% or gatifloxacin ophthalmic solution 0.3% treatment on corneal wound healing in pigmented rabbits following anterior keratectomy

Purpose These studies examined corneal healing rates, Type‐IV collagen and zonula occludens membrane‐associated protein (ZO‐1) expression, as well as aqueous PGE₂ and IL‐1β concentrations in pigmented rabbits treated with either moxifloxacin 0.5%, gatifloxacin 0.3% or BSS^® following anterior keratectomy. Methods Anterior keratectomy surgery was followed by topical administration with commercial ophthalmic formulations of either moxifloxacin or gatifloxacin or BSS^® (TID for 96 h). Images of the fluorescein‐stained healing corneas were analyzed for wound area. At 48 or 96 h following surgery, aqueous humor samples were collected and analyzed for the inflammatory mediators PGE₂ and IL‐1β using an ELISA. The corneas were subsequently evaluated using both scanning and transmission electron microscopy. In a second parallel study, corneas were evaluated at both 48 and 96 h for Type‐IV collagen and ZO‐1 expression using immunohistochemistry. Results Fluorescein‐stained corneal images at 96 h postsurgery demonstrated that 90% ± 8% re‐epithelialization for moxifloxacin, 81% ± 14% for gatifloxacin, and 88 ± 6% for BSS^® (P > 0.05). PGE₂ levels in the aqueous humor of fluoroquinolone treated eyes were reduced at 48 h compared to BSS^® treated eyes. IL‐1β was undetectable in all samples. No differences in Type‐IV collagen or ZO‐1 expression were observed between any treatment groups. There were no differences between groups in histological appearance or in ultrastructural healing processes. Conclusions These studies demonstrated that the commercial ophthalmic formulations of moxifloxacin and gatifloxacin were similar to each other in their effects on the levels of aqueous humor PGE₂ and rates of corneal wound re‐epithelialization.     

HPLC-PDA联合UPLC-Triple TOF MS法确证恩诺沙星注射液中的非法添加物

对恩诺沙星注射液中非法添加加替沙星的确证。通过HPLC-PDA法初筛发现1批恩诺沙星注射液中含有非法添加物,利用高分辨质谱对未知物进行筛查,推测出非法添加物为加替沙星,并用进行确证。结果显示,该批样品中的非法添加物为加替沙星。本研究为兽药中非法添加物筛查及定性确证提供了一个有效的思路与方法。