Publicaciones 2011-2020

@article{RN231,
title = {Determination of Etonogestrel and Ethinyl Estradiol from an Intrauterine Contraceptive Ring by Extraction and Derivative Spectrophotometry},
author = { M.I. Toral and F. Nacaratte and F. Nova},
url = {/brokenurl#<Go to ISI>://WOS:000348519800011},
doi = {10.1080/00032719.2014.968930},
issn = {0003-2719},
year = {2015},
date = {2015-01-01},
journal = {Analytical Letters},
volume = {48},
number = {6},
pages = {1009-1020},
abstract = {A new method for the determination and extraction of ethinyl estradiol and etonogestrel was developed for a pharmaceutical product consisting of a solid copolymer intrauterine ring for subsequent simultaneous quantification by ultraviolet-visible derivative spectrophotometry. The spectral variables were optimized for first derivative spectrophotometry with a smoothing factor of 4000 and an amplification factor of 10,000. A wavelength of 291.5nm was selected for the determination of ethinyl estradiol by a graphical method, while for etonogestrel, zero-crossing was used at 249.5nm. The limits of detection and quantification for ethinyl estradiol were 9.5x10(-7) and 9.0x10(-6)mol/L and 1.1x10(-6) and 3.2x10(-6)mol/L for etonogestrel, respectively. For the extraction method, the variables affecting the analytical signal were the extraction solvent, temperature, and extraction time; optimized conditions were 180min at 76 +/- 2 degrees C in acetonitrile. The method was applied successfully for the first time to analyze intrauterine contraceptive rings. The sample contained 11.7mg etonogestrel and 2.7mg ethinyl estradiol; the recoveries were 93.6 +/- 1.1% etonogestrel and 97.9 +/- 1.5% ethinyl estradiol relative to the nominal concentration. The importance of this method involves its implementation in pharmaceutical laboratories.},
keywords = {contraceptive cyproterone-acetate, desogestrel, estradiol, ethinyl etonogestrel, formulation, intrauterine mass-spectrometry, pharmaceutical plasma properties, release ring, spectrophotometry},
pubstate = {published},
tppubtype = {article}
}

@article{RN111,
title = {Parallel Determination of Desogestrel and 17 Alpha-Ethinylestradiol in Pharmaceutical Formulation by Derivative Spectrophotometry},
author = { M.I. Toral and F. Nacaratte and F. Nova-Ramirez and R. Otipka},
url = {/brokenurl#<Go to ISI>://WOS:000331237700031},
issn = {0717-9707},
year = {2013},
date = {2013-01-01},
journal = {Journal of the Chilean Chemical Society},
volume = {58},
number = {2},
pages = {1779-1784},
abstract = {This work presents a rapid and simple method for the parallel determination of Desogestrel (DSG) and 17 alpha-Ethinylestradiol (EE2) by second order derivative spectrophotometry and its application in pharmaceutical formulations. Study of the effect of the solvents, excipients and spectral behavior is also included. Acetonitrile was selected as a solvent; subsequently the samples were evaluated by second order derivatives, using a smoothing factor of 8,000 and a scale factor of 10(4). The EE2 determination was carried out using the graphical method at 288 nm and DSG by the zero-crossing method at 220 nm. The determination ranges were found to be between 1.5.10(-6) and 5.10(-4) mol/L and 1.7.10(-7) to 1.0.10(-3) mol/L for DSG and EE2, respectively., The homogenized tablets are divided in two fractions, the first, called sample A, was dissolved in acetonitrile, which contains the absorbents species that is polyvidone, DGS and EE2, the latter is determined directly at 288 nm. Meanwhile, in the second fraction (sample B), after extract with water the polyvidone and partially EE2, it is possible determine DGS at 220 nm. When the pharmaceutical formulation contains Vitamin E (Vit. E) is necessary to use an equations system to be evaluated in sample B.},
keywords = {desogestrel, estradiol, estrogens, ethinyl ethinylestradiol, formulations, gestodene levonorgestrel, mass-spectrometry, oral-contraceptives, pharmaceutical povidone, spectral study},
pubstate = {published},
tppubtype = {article}
}