Eman Elzanfaly

This work is concerned with the determination of a mixture of phenytoin, phenobarbitone and methylphenobarbitone by two Werent techniques. The first one depends on the simultaneous quantitative densitometric evaluation of thin layer chromatograms of the three drugs. The second is the application of quantitative 'H-NMR spectrometry for the simultaneous determination of phenobarbitone and methylphenobahiione in the presence of phenytoin, while phenytoin was determined in this
mixture by modifying the benzophenone spectrophotometric procedure

This paper reports the construction and evaluation of two ion selective electrodes for the determination midodrine hydrochloride (MD) by direct potentiometry in pure drug substance and in tablet formulations. Precipitation based technique was used for fabrication of the first membrane sensor (sensor 1) using phosphotungestate (PT) and dioctylphthalate (DOP) as cation exchanger and solvent mediator, respectively. β-cyclodextrin (β-CD)-based technique with PT as a fixed anionic site in PVC matrix was used for fabrication of the second membrane sensor (sensor 2). The proposed sensors showed fast, stable Nernstian responses of 54 and 56 mV/decade for sensors 1 and 2, respectively, across a relatively wide MD concentration range (1 × 10–4 to 1 × 10–1 mol/L and 5 × 10–5 to 1 × 10–1 mol/L for sensor 1 and 2, respectively) in the pH range of 5–7. Sensor 1 and sensor 2 can be used for three and two weeks, respectively without any measurable change in sensitivity. The suggested electrodes succeeded to determine intact MD in the presence of up to 10% of its degradation product and displayed good selectivity in presence of common inorganic and organic species.