text: A novel membrane sensor for histamine H1-receptor antagonist "fexofenadine".
  The construction and general performance of thirteen new polymeric membrane sensors for the determination of fexofenadine hydrochloride based on its ion exchange with reineckate, tetraphenylborate and tetraiodomercurate have been studied. The effects of membrane composition, type of plasticizer, pH value of sample solution and concentration of the analyte in the sensor internal solution have been thoroughly investigated. The novel sensor based on reineckate exchanger shows a stable, potentiometric response for fexofenadine in the concentration range of 1 x 10(-2) - 2.5 x 10(-6) M at 25 degrees C that is independent of pH in the range of 2.0 - 4.5. The sensor possesses a Nernstian cationic slope of 62.3+/-0.7 mV/concentration decade and a lower detection limit of 1.3 x 10(-6) M with a fast response time of 20 - 40 s. Selectivity coefficients for a number of interfering ions and excipients relative to fexofenadine were investigated. There is negligible interference from almost all studied cations, anions, and pharmaceutical excipients, however, citrizine that has a structure homologous to that of fexofenadine was found to interfere. The determination of fexofenadine in aqueous solution shows an average recovery of 99.83% with a mean relative standard deviation (RSD) of 0.5%. Direct potentiometric determination of fexofenadine in tablets gave results that compare favorably with those obtained by standard spectrophotometric methods. Potentiometric titration of fexofenadine with phosphomolybdic acid as a titrant has been monitored with the proposed sensor as an end point indicator electrode.
entities.id: T10 T11 T12 T13 T14 T1 T2 T3 T4 T5 T6 T7 T8 T9
entities.type: CHEMICAL CHEMICAL CHEMICAL CHEMICAL GENE-Y CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL
entities.text: fexofenadine fexofenadine histamine fexofenadine histamine H1-receptor citrizine fexofenadine hydrochloride fexofenadine fexofenadine fexofenadine fexofenadine phosphomolybdic acid tetraphenylborate tetraiodomercurate