Publicaciones 2011-2020

@article{RN174,
title = {Determination and Co-Estimate of the Chlormadinone Acetate and 17 Alpha-Ethinyl Estradiol in Pharmaceutical Formulation and Drinking Water Samples by Digital Derivative Spectophotometry},
author = { C. Soto and R. Otipka and M.I. Toral and D. Pino and D. Contreras and J. Yanez},
url = {/brokenurl#<Go to ISI>://WOS:000342613100019},
doi = {10.4067/S0717-97072014000200019},
issn = {0717-9707},
year = {2014},
date = {2014-01-01},
journal = {Journal of the Chilean Chemical Society},
volume = {59},
number = {2},
pages = {2485-2489},
abstract = {In this work are presented two methods for the simultaneous determination of 17 alpha-ethinylestradiol (EEL) and chlormadinone acetate (CMA) by second order derivative spectrophotometry., The first analytical method proposed is based in the dissolution and extraction of both drugs in acetonitrile. The solution was directly evaluated by second order derivative spectrophotometry with a smoothing factor of 8,000 and a scale factor of 10,000. The determination of EEL and CMA was carried out to 296,6 and 291.8 nm, respectively. The detection limits (3.3 sigma criterion) for EEL and CMA were 6.9 x 10(-7) and 9.8 x 10(-8) mol/L, respectively., Furthermore, a study of the effect of the excipients containing in the pharmaceutical formulation was included. Polyvidone presents greater tendency to produce interference, but its spectral bands are located between 215 and 240 nm, so these bands do not interferes spectrally in the simultaneous determination of EEL and CMA. Both drugs were extracted from the pharmaceutical formulation with acetonitrile, obtaining a good recovery relative to the nominal content., The second method is a screening method and was applied in fortified drinking water. In this method, drugs were extracted in chloroform, which was then removed with N-2 and the residue was redissolved in acetonitrile. Due to the difference in the procedure in relation to the pharmaceutical formulation a new analytical parameters were obtained. For EEL this parameters were very similar to those obtained directly in solution, however these were higher for CMA, which could be attributed to that under these conditions was found a higher standard deviation of the blank. Recoveries of fortified samples were 81.8 +/- 1.5% and 101.1 +/- 0.73% for EEL and CMA, respectively.},
keywords = {alpha-ethinyl chlormadinone derivative electrode estradiol, ethinylestradiol, formulations, gestodene, human least-squares, liquid-chromatography, mass-spectrometry, method, oral-contraceptives, performance pharmaceutical plasma, screening spectrophotometry, tandem},
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}
}