ABSTRACT
A new carbon paste electrode selective for piribedil (PD) was prepared and fully characterized in terms of composition, usable pH range, response time and thermal stability. The electrode active recognition is by liquid ion-exchange mechanism via the use of piribedil phosphomolybdate as ion-exchanger dissolved in tricresyl phosphate as a more suitable solvent mediator for the paste. The modified electrode showed a Nernstian slope of 58.4+/-0.6 mV over the concentration range of 7.5 x 10(-7) to 1 x 10(-3)M with an average recovery of 98.3-101.0% and R.S.D. of 0.45-1.31%. The electrode exhibits good selectivity for PD with respect to a large number of inorganic cations, organic cations, sugars and amino acids. The developed electrode was successfully used for the potentiometric determination of PD in its aqueous solutions, pharmaceutical preparation, and urine in batch and flow injection analysis (FIA).
Subject(s)
Dopamine Agonists/analysis , Piribedil/analysis , Algorithms , Calibration , Carbon , Chromatography, Ion Exchange , Dopamine Agonists/urine , Electrodes , Flow Injection Analysis , Humans , Hydrogen-Ion Concentration , Indicators and Reagents , Piribedil/urine , Plasticizers , Potentiometry , Regression Analysis , Solutions , Tablets , TemperatureABSTRACT
A new high performance liquid chromatographic procedure has been developed for the simultaneous quantification of piribedil (PD) and its three main basic metabolites in rat plasma and urine, without and after hydrolysis. The procedure relies on isolation of the compounds from plasma and urine constituents using the Sep-Pak C18 cartridge, with satisfactory recovery and specificity, and resolution by acetonitrile gradient elution on a C18 reversed phase column coupled to a UV detector monitored at 240 nm. The assay was linear over a wide range of concentrations for all compounds in both body fluids with mean within-day and day-to-day coefficient of variation (CV) and relative error (RE) generally below 10%. Plasma concentrations of PD and its metabolites at selected intervals and urinary recoveries of all compounds before and after enzymatic hydrolysis are presented.
