A sensitive, specific and rapid ultra-performance liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry (UPLC-APCI-MS/MS) method has been developed and validated for the determination of dexamethasone (DEX) in ocular tissues and biofluids of rabbits. Dexamethasone-d₅ (DEX-d₅) was used as an internal standard. Protein precipitation was used to extract the drug from ocular tissue homogenates, biofluids and plasma. Chromatographic separation was achieved on an Acquity C₁₈ column (100 × 2.1 mm, 1.7 μm) using a gradient run with a mobile phase composed of methanol and 5 mM ammonium formate in 0.1% formic acid in water buffer at a flow rate of 0.5 mL min⁻¹. A detailed method validation in two matrices (bovine serum albumin and phosphate buffer) was performed as per the FDA guidelines and the calibration curve obtained was linear (r² = 999) over the concentration range 200–100 000 pg mL⁻¹. A Sciex 6500+ coupled with a Waters Acquity UPLC (Ultra Performance Liquid Chromatography) system was operated in the multiple monitoring mode (MRM) during the analysis. The proposed method was applied to a rabbit ocular tissue distribution study after topical ophthalmic administration of dexamethasone and tobramycin suspension.

中文翻译：

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局部给药后灵敏的UPLC-APCI-MS / MS测定地塞米松的方法及其在兔眼组织分布研究中的应用

灵敏，特异，快速的超高效液相色谱-常压化学电离串联质谱法（UPLC-APCI-MS / MS）已开发并验证了用于测定兔眼组织和生物流体中地塞米松（DEX）的方法。地塞米松-d ₅（DEX-d ₅）被用作内标。蛋白沉淀用于从眼组织匀浆，生物流体和血浆中提取药物。在Acquity C ₁₈色谱柱（100×2.1 mm，1.7μm）上进行色谱分离，使用由甲醇和5 mM甲酸铵在0.1％甲酸水溶液缓冲液中流动的流动相，流速为0.5 mL，进行梯度洗脱最小^-1。根据FDA指南，在两种基质（牛血清白蛋白和磷酸盐缓冲液）中进行了详细的方法验证，所获得的校准曲线在200–100 000 pg mL ^-1的浓度范围内呈线性（r ² = 999）。在分析过程中，Sciex 6500+与Waters Acquity UPLC（超高效液相色谱）系统结合使用。地塞米松和妥布霉素混悬液经局部眼科给药后，该方法用于兔眼组织分布研究。