Lidocaine and benzalkonium analysis and titration in drugs using new ISFETdevices

Two new ISFETs recently developed by us have now been applied to some pharm aceutical determinations in real matrices; the first device, responsive to cationic surfactants, was employed in the determination of benzalkonium chl oride contained in two different disinfectant solutions and in three types of commercial collyrium; the second device, responsive to cocaine hydrochlo ride, showed an appreciable response also to lidocaine hydrochloride and wa s used in the determination of lidocaine hydrochloride contained in some in jectable antibiotics. The repeatability and accuracy of measurements perfor med in the analysis of these pharmaceutical matrices using new solid state sensors were evaluated. A further aspect of the research involved the use o f two sensors to record complete titration curves for the determination of benzalkonium chloride, cocaine hydrochloride and lidocaine hydrochloride, r espectively. Applications to real matrices were also performed by analysing by titration pharmaceutical formulations containing benzalkonium chloride, or lidocaine hydrochloride and an illicit powder containing cocaine hydroc hloride and sugars. (C) 1998 Elsevier Science B.V. All rights reserved.