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Ruiz-Medina A.,University of Jaen | Molina-Garcia L.,University of Jaen | Llorent-Martinez E.J.,University of Jaen | Santos J.L.M.,Laboratory of Applied Chemistry | Fernandez-de Cordova M.L.,University of Jaen
Current Pharmaceutical Analysis | Year: 2013

Ibandronate is a potent nitrogen-containing bisphosphonate with a tertiary amine group, which does not easily form chromophore derivatives that can be detected by UV light of fluorescence emission. Here, a simple and straightforward automated multicommutated flow system, making use of water-soluble mercaptopropionic acid-capped CdTe quantum dots, was implemented for the fluorescence quantitation of ibandronate in pharmaceutical formulations. The developed approach was based on the analyte ability to establish surface interactions that resulted in quenched nanocrystals fluorescence intensity, being this effect proportional to the target compound's concentration. Size and concentration of quantum dots and pH of the media were some of the most relevant and influencing parameters studied. The proposed methodology allowed the determination of ibandronate in the range of 20-200 μg mL-1, with good repeatability (RSD<3%) and a sampling frequency of about 70 samples per hour. The results obtained in the analysis of pharmaceuticals showed excellent agreement with those provided by the manufacturer. © 2013 Bentham Science Publishers. Source


Bosco T.J.,Laboratory of Applied Chemistry | Bosco T.J.,French National Conservatory of Arts and Crafts | Laurent B.,Laboratory of Biophysics and Food Biochemistry | Porte C.,French National Conservatory of Arts and Crafts
American Journal of Food Technology | Year: 2012

The emulsion stability of nitromethane/vegetable oil is use for the rapid identification and quality control of vegetable oils. Using a volume ratio of nitromethane to vegetable oil of 3:7, the emulsion stability of nitromethane/vegetable oil increases in the following order: nitromethane/palm oil, nitromethane/peat-nut oil, nitromethane/corn oil, nitromethane/soybean oil and nitromethane/sesame oil. The nature of vegetable oil influences the emulsion stability. Falsification of sesame oil with 10% corn oil or any cheaper vegetable oil decreases significantly the stability of nitromethane/sesame oil emulsion. These results indicate that the method could be used for rapid identification and quality control of vegetable oils. © 2012 Academic Journals Inc. Source


Gomes M.J.,Laboratory of Applied Chemistry | Martins S.,University of Porto | Martins S.,University of Southern Denmark | Ferreira D.,University of Porto | And 2 more authors.
International Journal of Nanomedicine | Year: 2014

Alopecia is a dermatological disorder, commonly known as hair loss, which affects up to half of the Caucasian male population by middle age, and almost all (95%) Caucasian men by old age. Considering that alopecia affects so many people and that there is currently no scientifically proven treatment with few side effects, new drug-delivery systems able to improve alopecia therapy are urgently required. With this purpose in mind, the present study aimed to develop lipid nanoparticles (nanostructured lipid carriers) with the ability to incorporate and deliver anti-alopecia active compounds (minoxidil and fnasteride) into the dermis and hair follicles. Lipid nanoparticles, prepared by ultrasonication method, showed mean particle sizes around 200nm, which is suffcient for reaching the dermis and hair follicles, and zeta potential values around - 30mV, which indicates good physical stability. Over 28days of storage, no signifcant variations in these parameters were observed, which indicates that all nanoformulations are stable in storage over that period. Cryo-scanning electron microscope measurements showed that all the lipid nanoparticles exhibited a spherical shape and a smooth surface regardless of their composition. Differential scanning calorimetry studies allowed the determination of phase transition temperatures and confrmed the recrystallization of the lipid nanoparticles (recrystallization index between 11% and 86%). A high loading effciency was achieved for fnasteride (between 70% and 90%), while less than 30% was achieved for minoxidil nanoparticles, over 28days. Controlled release assays in physiological conditions demonstrated that nanoparticles loaded with minoxidil yielded a prolonged release, as desired. Penetration assays through pig ear skin demonstrated that nanoparticles loaded with minoxidil and fnasteride had low levels of penetration. These results suggest that the proposed novel formulation presents several good characteristics indicating their suitability for dermal delivery of anti-alopecia active compounds. © 2014 Gomes et al. Source

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