Magda El-Maamly

Spectrophotometric and Chemometric Methods for SimultaneousDetermination of Two Anti-Hypertensive Drugs in their Combined DosageForm

In this study determination of Moexipril hydrochloride (MOX) and hydrochlorothiazide (HCT) were conducted by application of Spectrophotometric and Chemometric methods. Five different accurate, sensitive and reproducible methods were applied for the simultaneous determination of (MOX) and (HCT) in their bulk powder and pharmaceutical dosage form. The first method is the new absorbance subtraction (AS) method. The second method is the new amplitude modulation (AM) method. The third method is the new extended ratio subtraction (ERS) method coupled to ratio subtraction (RS) method. The fourth and fifth methods are multivariate calibration which includes Principal Component Regression (PCR) and Partial Least Squares (PLS). The suggested procedures were checked using laboratory prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparations. The validity of the proposed methods was further assessed by applying the standard addition technique. The results obtained by applying the proposed methods were statistically analyzed and compared with a reported method.

Construction of different types of ion-selective electrodes and validation of direct potentiometric determination of phenytoin sodium

The construction and performance characteristics of phenytoin sodium selective electrodes are detailed. Two types of electrodes: plastic membrane I and coated wire II, were constructed based on the incorporation of phenytoin sodium with tungstosilicic acid. The influence of membrane composition, kind of plasticizer, pH of the test solution, soaking time and the electrodes’ foreign ions were investigated. The electrodes showed a Nernstian response with a mean calibration graph slope of 30.9±0.1 and 28.9±0.1 mV decade−1 at 25°C for electrode I and II respectively, over a phenytoin sodium concentration range of 5×10−3−5×10−6 M and 1×10−3−1×10−6 M with a detection limit 1.3×10−6 M and 2.5×10−7 M for electrode I and II, respectively. The electrodes gave average selective precision and were usable within the pH range 6–10. Interference studies from common cations, alkaloids, sugars, amino acids and drug excipients are reported. The results obtained by the proposed electrodes were also applied successfully for the determination of the drug in pharmaceutical preparations and biological fluids.

Development of Nalbuphine‐Selective Membrane Electrode and Its Applications in Pharmaceutical Analysis

Abstract A nalbuphine ion‐selective PVC membrane electrode based on ion‐pair complex of nalbuphine with tetra phenyl borate was prepared with di‐butyl sebacate as a plasticizer. The electrode exhibits a linear response with a Nernstain slope 59.6 mV decate−1 at 25°C with the concentration range of 1×10−6−1×10−2 M nalbuphine. The electrode response was not sensitive to pH changes from 3.5–7 and not affected by possible interfering species such as common inorganic cations, sugars and amino‐acids. The electrode shows good stability, reproducibility and fast response. These characteristics of the electrode enable it to be used successfully for the determination of nalbuphine hydrochloride in pure form and in pharmaceutical preparations.