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Alves M.C.,Federal University of Juiz de fora | De Almeida P.A.,Federal University of Juiz de fora | Polonini H.C.,Federal University of Juiz de fora | Raposo N.R.B.,Federal University of Juiz de fora | And 2 more authors.
Quimica Nova | Year: 2014

RP-HPLC based analytical method for use in both quality control of green tea in a semisolid formulation and for in vitro drug release assays was developed and validated. The method was precise (CV < 5%), accurate (recovery between 98% and 102%), linear (R2 > 0.99), robust, and specific for the determination of epigallocatechin 3-gallate (EGCG), caffeine (CAF), and gallic acid (GA). In a diffusion cell chamber, the release rate of EGCG was 8896.01 μg cm-2. This data showed that EGCG will be able to exert its systemic activity when delivered though the transdermal formulation, due to its good flux rates with the synthetic membrane. Source


Piantavini M.S.,Laboratorio Of Controle Of Qualidade | Goncalves A.G.,Laboratorio Of Controle Of Qualidade | Trindade A.C.L.B.,Laboratorio Of Controle Of Qualidade | Merce A.L.R.,Laboratorio Of Equilibrio Quimico | Pontarolo R.,Laboratorio Of Controle Of Qualidade
Asian Journal of Pharmaceutical and Clinical Research | Year: 2013

Kojic acid (KA) is a fungal metabolite that is widely used as a depigmenting agent in cosmetics. Although there are sophisticated techniques to quantify this substance, such as HPLC and LC-MS, cheaper and more accessible methods employing electronic spectroscopy are still needed. We have developed and validated an UV spectrophotometric method for KA quantification that is based on the analyte's ability to form complexes with Al3+ ions. Superior selectivity is achieved with the presented method because KA-Al3+ complexes absorb at higher wavelengths than do non- complexed KA. This approach has proven to be applicable for detection of KA in both raw materials and cosmetic creams. Detection is possible even in the presence of hydroquinone, which is frequently combined with KA in cosmetic preparations. Method validation results at 305 nm indicated appropriate selectivity and linearity in the range of 5 to 50 μg/mL (r= 0.9998). Sensitivity evaluation showed a DL= 0.15 μg/mL and QL= 0.46 μg/mL. Accuracy (recovery) was near 100% (99,53 - 101,24%). Method precision was determined through repeatability (RSD 0.402%, 1.284% and 1.192% for 10, 15 and 20 μg/ mL, respectively) and intermediate precision (RSD 2.171%, 0.976% and 0.440% for 10, 15 and 20 μg/ mL, respectively). Robustness was evaluated by varying the pH, temperature and reading time. Source


Do Nascimento T.G.,Laboratorio Of Controle Of Qualidade | Basilio Junior I.D.,Laboratorio Of Controle Of Qualidade | MacEdo R.O.,Laboratorios Unificados Of Desenvolvimento E Ensaios Of Medicamentos | Moura E.A.,Laboratorios Unificados Of Desenvolvimento E Ensaios Of Medicamentos | And 4 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2010

This article characterizes the stability of indinavir sulfate using different analytical techniques of quality control to evaluate important steps in the manufacturing process of indinavir, specifically involving storage and compression. Indinavir A, B, and C were obtained from different suppliers and submitted to DSC, Karl Fisher, NIR, XRPD analyses and dissolution assay. DSC curves of indinavir presented endothermic peaks of fusion at 149-150 °C for indinavir A and B (form I) and 139-143 °C for indinavir C (form II). When indinavir A and B were submitted to high Relative Humidity (RH) pseudo-polymorphic form II was formed. Indinavir C converted into an amorphous substance when submitted to compression. Near infrared and Karl Fisher assays detected high values of water for indinavir C in relation to indinavir A and B. X-ray powder diffraction of indinavir B and C showed displacement of 0.05-0.10 θ in the peaks and higher angle of diffraction in relation to indinavir A. Amorphous indinavir C demonstrated a higher intrinsic dissolution rate than indinavir A and B. Indinavir form I should be monitored during the pharmaceutical process to avoid its conversion to indinavir form II or an amorphous substance which can alter the dissolution rate. © 2009 Akadémiai Kiadó, Budapest, Hungary. Source

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