Development and validation of an HPLC-UV method for accelerated stability study and pharmacokinetic analysis of venlafaxine

A reverse phase high performance liquid chromatography method has been developed and validated for accelerated stability study and determination of pharmacokinetic parameters of venlafaxine HCl. The chromatographic separation was carried out using ODS analytical column (250 × 4.6 mm i.d., 5 µm particle size). The mobile phase included acetonitrile, methanol and potassium dihydrogen phosphate buffer (30:30:40; pH 6.1) at a flow rate 1.5 mL min−1. UV-Visible detector was used at wavelength of 227 nm to monitor elutions. Retention time observed was 2.745 min. The method was validated for linearity, accuracy, precision, sensitivity and robustness. Accelerated stability study of venlafaxine HCl capsules was carried out at 40 and 50 ºC under 75% RH level. Suggested method was successfully applied for the pharmacokinetic analysis of venlafaxine hydrochloride tablets. Each of ten albino rabbits (≈ 1.2 kg each) was orally administered with 5 mg dose of venlafaxine HCl. The method was proved to be linear (R2 >0.998), accurate (98.25-99.27%), sensitive (LOD: 35ngmL−1; LOQ: 105 ng mL−1) and robust (RSD<1%). The drug showed stability at accelerated conditions of temperature and humidity. The main pharmacokinetic parameters of tested products were as follows: tmax was 2.5h, Cmax was 56.5 µg mL−1, t1/2 was 8.2 h, AUC0-36 was 845.9 µg h mL−1. The developed method is suitable to apply for quality control analysis and pharmacokinetic studies.

本研究建立并验证了一种反相高效液相色谱法（reverse phase high performance liquid chromatography），用于盐酸文拉法辛（venlafaxine HCl）的加速稳定性考察以及药代动力学参数测定。色谱分离采用十八烷基硅烷键合硅胶（Octadecylsilyl, ODS）分析色谱柱（250 × 4.6 mm内径，粒径5 µm）。流动相为乙腈、甲醇与磷酸二氢钾缓冲液（体积比30:30:40，pH 6.1），流速设为1.5 mL·min⁻¹。采用紫外-可见光检测器，以227 nm波长监测洗脱过程，测得目标物的保留时间为2.745 min。本方法对线性、准确度、精密度、灵敏度及耐用性进行了验证。对盐酸文拉法辛胶囊开展了加速稳定性研究，考察条件为40 ℃与50 ℃、相对湿度（Relative Humidity, RH）75%。所建立的方法成功应用于盐酸文拉法辛片剂的药代动力学分析：将10只体重约1.2 kg的白化家兔分别口服给予5 mg剂量的盐酸文拉法辛。经检验，本方法线性良好（R²＞0.998），准确度为98.25%~99.27%，灵敏度优异（检出限（Limit of Detection, LOD）为35 ng·mL⁻¹，定量限（Limit of Quantitation, LOQ）为105 ng·mL⁻¹），耐用性良好（相对标准偏差（Relative Standard Deviation, RSD）＜1%）。盐酸文拉法辛在加速温湿度条件下表现出良好稳定性。受试制剂的主要药代动力学参数如下：达峰时间（time of maximum concentration, t_max）为2.5 h，峰浓度（maximum concentration, C_max）为56.5 µg·mL⁻¹，消除半衰期（elimination half-life, t₁/₂）为8.2 h，0~36 h药时曲线下面积（Area Under Curve, AUC₀₋₃₆）为845.9 µg·h·mL⁻¹。本研究所建立的方法适用于质量控制分析以及药代动力学研究。