Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: nifedipine

Sortuj według:

Ogranicz wyniki do:

Electrochemical and Quantum Chemical Investigation on Adsorption of Nifedipine as Corrosion Inhibitor at API 5L X-52 Steel / HCl Acid Interface

Ikpi M. E., Abeng F. E.

Archives of Metallurgy and Materials

2020

Vol. 65, iss. 1

125--131

Nifedipine, a pyridine derivative was investigated as corrosion inhibitor for API 5L X-52 steel in 2 M HCl solution by potentiodynamic polarization, electrochemical impedance spectroscopy and quantum chemical calculations. Statistical tools were used to compare results of the experimental methods. The results showed that nifedipine is capable of inhibiting the corrosion of API 5L X-52 steel in 2 M HCl solution. Potentiodynamic polarization results reveal that nifedipine functions as a mixed-type inhibitor and presents an inhibition efficiency of about 78% at 500 ppm. Impedance data reveal an increasing charge transfer resistance with increasing inhibitor concentration and also shows comparable inhibition efficiency of about 89-94% at 500 ppm. Thermodynamic parameters imply that nifedipine is adsorbed on the steel surface by a physiochemical process and obeys Langmuir adsorption isotherm. The calculated molecular properties namely the highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy, chemical hardness, energy gap, dipole moment, electronegativity and global nucleophilicity index all show a positive relationship to the observed corrosion inhibition efficiency.

A new spectrofluorimetric method for determination of nifedipine in pharmaceutical formulations

Tabrizi A. B.

Chemia Analityczna

2007

Vol. 52, No. 4

635-643

A new, simple, sensitive, and fast spectrofluorimetric method for determination of nifedipine in pharmaceutical formulations has been presented. In the proposed procedure nifedipine was oxidized with Ce(IV) and the fluorescence of the produced Ce(III) was measured at 354 nm after excitation at 255 nm. The factors influencing oxidation of the drug were studied and optimized. Under the applied experimental conditions, the calibration plots were linear over nifedipine concentration range 0.05-2.0 mg L-1 The limit of detection was 0.015 mgL-1 and the relative standard deviation for 5 replicate determinations of nifedipine at 1.0 mg L-1 concentration level was 1.53%. Good recoveries in the range 95-104% were obtained in spiked samples. The proposed method was successfully applied to the determination of nifedipine in pharmaceutical formulations.

Przedstawiono nową, czułą, prostą i szybką spektra fluory metryczną metodę oznaczania nifedypiny w preparatach farmaceutycznych. Metoda postępowania polega na utlenieniu nifedypiny za pomocą Ce(IV) a fluorescencja powstającego Cc(III) jest mierzona przy długości fali 354 nm (po wzbudzeniu za pomocą promieniowania o ). = 255 nm). Zbadano i zoptymalizowano czynniki wpływające na utlenianie leku. W ustalonych warunkach doświadczalnych krzywa kalibracyjna była liniowa w zakresie stężeń nifedypiny 0:05-2,0 mg L-1, Granica wykrywalności wynosiła 0,015 mg L-1 a względne odchylenie standardowe wyznaczone na poziomie stężeń nifedypiny 1,0 mg L-1 na podstawie 5-u równo ległych oznaczeń wynosiło 1,53%. Odzysk dla próbek z dodatkiem ieku był w granicach 95-104%. Metodę zastosowano z powodzeniem do oznaczania nifedypiny w preparatach farmaceutycznych.