Determination of tetrahydroisoquinolines by reversed-phase liquid chromatography with gradient elution and amperometric detection

1982 ◽  
Vol 54 (2) ◽  
pp. 186-189 ◽  
Author(s):  
R. L. St. Claire ◽  
G. A. S. Ansari ◽  
Creed W. Abell
Keyword(s):  
Liquid Chromatography ◽  
Amperometric Detection ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Phase Liquid

scholarly journals Simultaneous Determination of Bifonazole and Tinctures of Calendula Flower in Pharmaceutical Creams by Reversed-Phase Liquid Chromatography

2005 ◽  
Vol 88 (6) ◽  
pp. 1649-1654 ◽  
Author(s):  
Carola F Ferreyra ◽  
Cristina S Ortiz
Keyword(s):  
Liquid Chromatography ◽  
Pharmaceutical Formulations ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Pharmaceutical Products ◽  
Stability Studies ◽  
Reversed Phase Liquid Chromatography ◽  
Compound I ◽  
Phase Liquid

Abstract The aim of this research was to develop and validate a sensitive, rapid, easy, and precise reversed-phase liquid chromatography (LC) method for stability studies of bifonazole (I) formulated with tinctures of calendula flower (II). The method was especially developed for the analysis and quantitative determination of I and II in pure and combined forms in cream pharmaceutical formulations without using gradient elution and at room temperature. The influence on the stability of compound I of temperature, artificial radiation, and drug II used for the new pharmaceutical design was evaluated. The LC separation was carried out using a Supelcosil LC-18 column (25 cm × 4.6 mm id, 5 μm particle size); the mobile phase was composed of methanol–0.1 M ammonium acetate buffer (85 + 15, v/v) pumped isocratically at a flow rate of 1 mL/min; and ultraviolet detection was at 254 nm. The analysis time was less than 10 min. Calibration graphs were found to be linear in the 0.125–0.375 mg/mL (rI = 0.9991) and 0.639–1.916 mg/mL (rII = 0.9995) ranges for I and II, respectively. The linearity, precision, recovery, and limits of detection and quantification were satisfactory for I and II. The results obtained suggested that the developed LC method is selective and specific for the analysis of I and II in pharmaceutical products, and that it can be applied to stability studies.

scholarly journals Determination of Acesulfame and Sucralose in Oral Electrolyte Maintenance Solution by Liquid Chromatography

2003 ◽  
Vol 86 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Paul Johns ◽  
Lobat Dowlati
Keyword(s):  
Liquid Chromatography ◽  
Amperometric Detection ◽  
Reversed Phase ◽  
Alternative Methods ◽  
Analyte Concentration ◽  
Reversed Phase Liquid Chromatography ◽  
Intermediate Precision ◽  
Phase Liquid ◽  
Method Accuracy

Abstract A method was developed for the direct, simultaneous determination of acesulfame and sucralose in oral electrolyte maintenance solution (OEMS). Analyte separation and quantitation were achieved by gradient reversed-phase liquid chromatography (LC) and UV absorbance at 192 nm, respectively. Detection at a second wavelength, 214 nm, was used to check sucralose peak purity; 20 μL OEMS was injected without preparation or dilution. System linearity was demonstrated as 192 nm peak area versus analyte concentration at 80–120% OEMS sweetener fortification (r > 0.999, and all residuals <0.5%, for both acesulfame and sucralose). Spike recoveries for OEMS samples prepared at 3 spiking levels (80, 100, and 120% sweetener fortification) ranged from 100.3 to 102.0% for acesulfame, and from 97.9 to 102.3% for sucralose. In a second assessment of method accuracy, the same spiked OEMS samples were tested by 2 alternative methods: acesulfame (LC/UV at 230 nm) and sucralose (anion exchange–pulsed amperometric detection). Results for the alternative acesulfame method were within 1.2%, and for the alternative sucralose method within 6.0%, of the corresponding results obtained by the 192 nm method. Repeatability and intermediate precision RSD values were <1% for acesulfame and <3% for sucralose. The limits of quantitation were 1.6 and 32 mg/L for acesulfame potassium and sucralose, respectively. Despite the weak UV absorptivity of sucralose and the consequent small size of its LC peak, no evidence was found for sucralose interference in any of the commercial OEMS flavors.

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