Determination of carbendazim, fuberidazole and thiabendazole by three-dimensional excitation–emission matrix fluorescence and parallel factor analysis Original Research Article

A novel method based on differential pulse polarography (DPP) was developed for the non-destructive monitoring of pyroxicam (PXC) release from biodegradable and sterically stabilized poly(lactide-co-glycolide) (PLGA)–monomethoxypoly(ethyleneglycol) (mPEG) nanoparticles. The nanoparticles were prepared by a precipitation-solvent diffusion method. Approximately 30 mg l−1 PXC was entrapped in the nanoparticles leading to a 0.56% PXC loading value. The continuous in vitro monitoring yielded the respected release profile and it was found that virtually all the drug was released within 3 days. There was no interference of the PLGA–mPEG dispersion on the DPP signal of PXC. DPP results were compared with those obtained from the application of the currently used, more cumbersome and destructive, methodology involving hydrolysis of the polymeric nanoparticles and subsequent determination of the drug spectrophotometrically. A less than 1.5% difference was observed leading to the conclusion that the proposed methodology may be considered to be suitable for the in situ non-destructive determination of the in vitro release profile of electroactive drugs from nanoparticles.