Determination of local anesthetics in illegal products using HPLC method with amperometric detection.

An HPLC method with amperometric detection was developed for analysis of two local anesthetics (lidocaine and benzocaine) in products for delaying ejaculation illegally marketed in Polish sex shops. Chromatographic elution on an RP column C18 with mobile phase composed of acetate buffer with acetonitrile, provides an optimal separation not only of active substances but also electroactive preservatives which are occasionally added to cosmetic creams (methylparaben and propylparaben). Application of glassy carbon electrode as a working electrode and a procedure with pulsed potential waveforms enables a sensitive, accurate measurement within a relatively short analysis time (250 s). This method has been successfully employed for the determination of local anesthetics in products under investigation. The obtained results show that most samples contained therapeutic concentrations of lidocaine or benzocaine. According to European law, a sale of products containing lidocaine or benzocaine outside the pharmacy sector is forbidden.

Determination of atracurium, cisatracurium and mivacurium with their impurities in pharmaceutical preparations by liquid chromatography with charged aerosol detection.

The Corona CAD (charged aerosol detection) is a new type of detector introduced for LC applications that has recently become widely applied in pharmaceutical analysis. The Corona CAD measures a physical property of analyte and responds to almost all non-volatile species, independently of their nature and spectral or physicochemical properties. The LC method with charged aerosol detection was developed for the determination of three isomers of atracurium, cisatracurium and also three isomers of mivacurium with their impurities. The limit of quantitation for laudanosine was 1 microg ml(-1). The elaborate method for the analysis of those active substances and laudanosine proved to be fast, precise, accurate and sensitive. All other impurities were identified using time-of-flight mass spectrometry with electrospray ionization.