Development of a Monolithic HPLC-ECD Method for the Determination of Ropinirole HCl in Mouse Sera and Dosage Forms

Aim: A highly selective, sensitive, and rapid to establish an innovative way to determine Ropinirole HCl in mouse sera and pharmaceutical formulations.

Study Design: High-performance liquid chromatography (HPLC) method with electrochemical detector (ECD) was developed.

Place and Duration of Study: College of Pharmacy, King Saud University, between May 2015 and December 2015.

Methodology: The chromatographic separation was achieved on a reversed phase RP-18e Chromolith Performance column (100 mm × 4.6 mm) with a mobile phase of methanol: 50 mM sodium dihydrogen phosphate (pH 4.5) (10:90, v/v) pumped at a flow rate of 2.0 mLmin-1. Paracetamol was used as an internal standard (IS). Ropinirole HCl and the IS were extracted from mouse sera by using the deproteinisation procedure, followed by injection of an aliquot of the supernatant into the chromatographic system. The separation of the studied drugs was achieved within 3 min.

Results: The proposed HPLC-ECD method was validated for its selectivity, linearity, accuracy, precision, robustness and stability. The calibration curves in serum showed excellent linearity (r = 0.9980) over concentrations ranging from 10 to 2400 ng mL−1 for ROP with limit of detection (LOD) equal to 2.5 ng mL−1 which is lower than those obtained with a UV-VIS detector.

Conclusion: The method was successfully utilised for Ropinirole HCl quantification in mouse sera samples and good recoveries were obtained without interference from endogenous uric acid and dopamine. Moreover, the assay was successfully applied in a pharmacokinetic study. In addition, the proposed HPLC-ECD method was applied in the determination of ROP content in tablet dosage forms, with good recoveries were obtained without interference from their excipients; Na+, K+, Ca2+, Mg2+, lactate, sucrose, lactose and starch.