Quantification of propranolol in rat plasma by LC- MS/MS using tramadol as an internal standard: Application to pharmacokinetic studies in TAA-induced liver fibrotic rats

Abstract

A simple, rapid and selective liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is developed and validated for quantification of propranolol without the sample extraction step in rat plasma using tramadol as an internal standard (IS). The analytes are separated using an isocratic mobile phase which consist of methanol and 10 mm ammonium formate (70/30, v/v) on an isocratic UK-C18 (Imtakt Unison 2.0 × 50 mm, 3 μm) column and was analyzed by MS/MS in the multiple reaction monitoring (MRM) mode using the transitions of respective (M+H)+ ions, m/z 260.0→116.2 and m/z 264.2→58.2 for quantification of propranolol and IS, respectively. The standard calibration curves showed good linearity within the range of 2.0 to 800.0 ng/ml (r2 = 0.999, 1/x2 weight). The lower limit of quantification (LLOQ) was 2 ng/ml. The retention time of propranolol and IS were 1.12 and 0.939 min which means that it is the potential for the high-through put potential of the proposed method. In addition, no significant metabolic compounds were found to interfere with the analysis. Acceptable precision and accuracy were obtained for the concentrations over the standard curve range. The validated method was successfully applied for the pharmacokinetic studies after 2 mg/kg of propranolol HCl in the thioacetamide (TAA)-induced fibrotic rats. Key words: Propranolol, liquid chromatography, mass spectrometry, pharmacokinetics, thioacetamide, liver fibrosis.