Assay of Famotidine in Pure Solutions and Pharmaceutical Preparatives using the Coated- graphite Electrode as a Detector in the FlA System

A simple electrochemical method was developed to estimate famotidine (FMT) in pure solutions and pharmaceutical preparatives by a flow-injection analysis system (FlA). This method includes preparation of a coated graphite electrode using FMT with the Phosphotungstic acid precipitant (PTA), di-butyl phthalate (DBP) and poly vinyl chloride (PVC). The electrode characteristics were examined by studying the optimum conditions, the carrier current, the injected model size, flow rate, the reaction coil length, pH, the range of concentrations, the minimum Nernst response, the response time, the detection limits, and the study also included identifying the electrode selectivity of the toward other interfering ions. The electrode showed that the best Nernst slope for the calibration curve was at 33.82 mv/decade within linear range of (1.0 × 10-6- 1.0 × 10-1M), correlation coefficient (R2) 0.9999, response time 10 seconds, the estimating speed is 90 sample/hour, while the rate of dilution degree (D) is 2.6452. The obtained results confirmed that it is of high accuracy and precision (Err 0.119%), (Rec 100.11%), (RSD 0.1233%). The proposed method was successfully applied to assay of FMT in commercial tablet forms.

Preparation and Description of Potentiometric Electrode for the Limitation of Sulbutamol Sulphate

A new sulbatamol sulphate SBS membrane electrode was prepared that utilizing for its determination ; depend on the forming of the association complex ion of sulbatamol sulphate by the phosphotungstate counter anion deposed in poly vinyl chloride PVC polymer, by use a (Di-n- Octyl Phenyl Phthalate)(Dopp) as the plastizier substance, in membrane.The features properties as well as the behavior of it .The new electrode have been elaborated. The concentrations of medicine by utillizing This sensor show a fast, stable, near-Nernstian response in the range (1x10-1-1x10-6) mol/ L were determined with correlation coefficient of about (r = 0.9991) and with of a relative standard about 0.416 additionally deviation relative standard error of 1.710  %.pot The nernast linearity slop was founded and it is equal to 28.9 mV/decade and the detection limit was 4.1 x 10-6 mol/ L.The electrode selectivity coefficient Ki,j was calculated, in the existence of several interferences cations with confirmed medicine solutions. It was found the pH range response is in the range of (3 -7), with the response time of (30 – 116) sec. for various  concentrations at room temperture , the lifetime for  electrode was found to be more than 21 days. The electrode was successfully used for potentiometric limitation of sulbatamol sulphate in several pharmaceutical drugs by using direct potentiometry.

Properties of Dopamine Release and Uptake in the Songbird Basal Ganglia

Vocal learning in songbirds requires a basal ganglia circuit termed the anterior forebrain pathway (AFP). The AFP is not required for song production, and its role in song learning is not well understood. Like the mammalian striatum, the striatal component of the AFP, Area X, receives dense dopaminergic innervation from the midbrain. Since dopamine (DA) clearly plays a crucial role in basal ganglia–mediated motor control and learning in mammals, it seems likely that DA signaling contributes importantly to the functions of Area X as well. In this study, we used voltammetric methods to detect subsecond changes in extracellular DA concentration to gain better understanding of the properties and regulation of DA release and uptake in Area X. We electrically stimulated Ca2+- and action potential–dependent release of an electroactive substance in Area X brain slices and identified the substance as DA by the voltammetric waveform, electrode selectivity, and neurochemical and pharmacological evidence. As in the mammalian striatum, DA release in Area X is depressed by autoinhibition, and the lifetime of extracellular DA is strongly constrained by monoamine transporters. These results add to the known physiological similarities of the mammalian and songbird striatum and support further use of voltammetry in songbirds to investigate the role of basal ganglia DA in motor learning.