Simultaneous determination of eperisone hydrochloride and paracetamol in mouse plasma by high performance liquid chromatography-photodiode array detector

• First HPLC-PDA assay for Eperisone and Paracetamol analysis in mouse plasma.
• Simultaneous determination of Eperisone and Paracetamol in biological matrices.
• Method tested for PK profiles in biological matrix.
• Validation procedure fulfilling ICH Q2(R1) guidelines.

This paper reports the validation of a quantitative high performance liquid chromatography-photodiode array (HPLC-PDA) method for the simultaneous analysis, in mouse plasma, of eperisone hydrochloride and paracetamol by protein precipitation using zinc sulphate–methanol–acetonitrile.The analytes were resolved on a Gemini C18 column (4.6 mm × 250 mm; 5 μm particle size) using a gradient elution mode with a run time of 15 min, comprising re-equilibration, at 60 °C (±1 °C). The method was validated over the concentration range from 0.5 to 25 μg/mL for eperisone hydrochloride and paracetamol, in mouse plasma. Ciprofloxacin was used as Internal Standard.Results from assay validations show that the method is selective, sensitive and robust. The limit of quantification of the method was 0.5 μg/mL for eperisone hydrochloride and paracetamol, and matrix-matched standard curves showed a good linearity, up to 25 μg/mL with correlation coefficients (r2) ≥ 0.9891. In the entire analytical range the intra and inter-day precision (RSD%) values were ≤1.15% and ≤1.46% for eperisone hydrochloride, and ≤0.35% and ≤1.65% for paracetamol. For both analytes the intra and inter-day trueness (bias%) values ranged, respectively, from −5.33% to 4.00% and from −11.4% to −4.00%.The method was successfully tested in pharmacokinetic studies after oral administration in mouse. Furthermore, the application of this method results in a significant reduction in terms of animal number, dosage, and improvement in speed, rate of analysis, and quality of pharmacokinetic parameters related to serial blood sampling.