Evaluation of olive oils from the Mediterranean region by UV-Vis spectroscopy and Independent Component Analysis.

Extra-virgin olive oil (EVOO) from Mediterranean were analyzed by Ultraviolet-Visible (UV-Vis) spectroscopy and Independent Component Analysis (ICA). The use of ICA resolution provided information over dienes (primary oxidation compound), polyphenolic compounds, tocopherol, carotenoids and chlorophylls when EVOO was evaluated by UV-Vis spectroscopy. Based on these data, ICA could be used to determine the contribution of chemical compounds to the composition of EVOO produced in different regions from Mediterranean. The results suggest that the combination of UV-Vis measurements and ICA makes possible the EVOO evaluation, and can contribute to suggesting that a foodstuff comes from an alleged origin. The proposed methodology is a low cost, fast and sample preparation free methodology to highlights the EVOO characteristics produced in the Mediterranean region.

Chemometric-Assisted Spectrophotometric Method for the Simultaneous Quantitative Determination of Ezetimibe and Simvastatin in Their Combined Dosage Forms.

The multivariate method, partial least-squares (PLS), was used as a calibration procedure for the simultaneous UV spectrophotometric determination of ezetimibe and simvastatin in their pharmaceutical forms. The method was developed and satisfactorily validated according to International Conference on Harmonization guidelines with respect to specificity, linearity, precision, accuracy, and robustness. In this study, the PLS algorithms are based on the absorption spectra of 25 different mixtures of drugs obtained by a multilevel factorial design. The method was linear in the concentration range of 2-8 µg/mL for ezetimibe and 4-16 µg/mL for simvastatin (r2 > 0.99; n = 7) at wavelengths of 238 and 247 nm, respectively. The LOD and LOQ were 0.28 and 0.93 µg/mL for ezetimibe and 0.16 and 0.53 µg/mL for simvastatin, respectively. Precision and accuracy data, evaluated by RSD, were lower than 2%. The method, which proved to be robust, was performed with a 2n full-factorial design. The validated method is simple and low cost, has a low use of polluting reagents, and is environmental friendly. Therefore, the proposed method was successfully applied for the simultaneous quantitative analysis of ezetimibe and simvastatin in commercial formulations.

Green method based on a flow-batch analyzer system for the simultaneous determination of ciprofloxacin and dexamethasone in pharmaceuticals using a chemometric approach.

A green FBA method with UV detection was developed for simultaneous determination of ciprofloxacin (CIP) and dexamethasone (DEX) in ophthalmic and otic preparations. A lab-made mixing detection chamber (MDC) was designed and coupled to the spectrophotometer in order to perform the mixing of solutions and the detection in the same receptacle. Only water was used as solvent and no previous separation of the components was required. Both analytes have a strong absorption between 190 and 370 nm in aqueous medium, at pH 7. However, the spectrum of DEX is embedded in the CIP spectrum. Thus, while CIP was analyzed using univariate calibration, DEX analysis was carried out comparing partial least squares (PLS-1) and multiple linear regression (MLR). The latest required a previous variable selection step, which was performed using the genetic algorithm (GA) and the successive projections algorithm (SPA). The FBA system made it possible to automatically prepare the calibration and validation sets. The statistical parameters, in terms of relative errors of calibration and prediction, were acceptable for the determination of both CIP and DEX. Also, a comparative study of chemometric models was carried out. Commercial samples were analyzed and the obtained results are in close agreement with HPLC pharmacopeia methods. The joint interval test for the slope and the intercept was used to test for the presence of bias. There were no statistical differences between the proposed method and the reference method (α=0.05). The sample throughput was 10h(-1). The combination of automation and chemometric tools allows us to develop an environmental friendly method for the quality control of CIP and DEX in pharmaceuticals.

Comparative study of analytical methods by direct and first-derivative UV spectrophotometry for evaluation of losartan potassium in capsules / Estudo comparativo de métodos analíticos por espectrometria de UV directa e derivada de primeira ordem para a avaliação de losartano potássico em cápsulas

Losartan potassium is an antihypertensive non-peptide agent, which exerts its action by specific blockade of angiotensin II receptors. The aim of the present study was the validation and application of analytical methods for the quality control of losartan potassium 50 mg in pharmaceutical capsules, using direct and first-derivative UV spectrophotometry. Based on losartan potassium spectrophotometric characteristics, a signal at 205 nm of the zero-order spectrum and a signal at 234 nm of the first-derivative spectrum, were found adequate for quantification. The results were used to compare these instrumental techniques. The linearity between the signals and concentrations of losartan potassium in the ranges of 3.0-7.0 mg L-1 and 6.0-14.0 mg L-1 for direct and first-derivative spectrophotometry in aqueous solutions, respectively, presented a correlation coefficient (r) of 0.9999 in both cases. The methods were applied for losartan potassium in capsule dosage obtained from local pharmacies, and were shown to be efficient, easy to apply and low cost. These methods do not use polluting reagents and require relatively inexpensive equipment.

O losartano potássico é um agente anti-hipertensivo não peptídico, que exerce sua ação por bloqueio específico dos receptores da angiotensina II. Este trabalho propôs a validação e aplicação de métodos analíticos orientados ao controle de qualidade de losartano potássico 50 mg na forma farmacêutica cápsula, utilizando a espectrofotometria direta e derivada de primeira ordem na região do UV. Baseado nas características espectrofotométricas de losartano potássico, um sinal a 205 nm do espectro de ordem zero e um sinal a 234 nm do espectro de primeira derivada foram adequados para a quantificação. Os resultados foram usados para comparar essas duas técnicas instrumentais. O coeficiente de correlação entre as respostas e as concentrações de losartano potássico na faixa de 3,0-7,0 mg L-1 e 6,0-14,0 mg L-1 para espectrofotometria direta e derivada de primeira ordem em solução aquosa, respectivamente, foi de (r) of 0,9999 para ambos os casos. Os métodos foram aplicados para quantificação de losartano potássico em cápsulas obtidas de farmácias de manipulação locais e demonstraram ser eficientes, fáceis de aplicar e de baixo custo. Além disso, não necesitam de reagentes poluentes e requerem equipamentos economicamente viáveis.

Development and validation of sensitive methods for determination of sibutramine hydrochloride monohydrate and direct enantiomeric separation on a protein-based chiral stationary phase.

Sibutramine hydrochloride monohydrate, chemically 1-(4-chlorophenyl)-N,N-dimethyl-alpha-(2-methylpropyl) hydrochloride monohydrate (SB.HCI.H20), was approved by the U.S. Food and Drug Administration for the treatment of obesity. The objective of this study was to develop, validate, and compare methods using UV-derivative spectrophotometry (UVDS) and reversed-phase high-performance liquid chromatography (HPLC) for the determination of SB.HCI.H20 in pharmaceutical drug products. The UVDS and HPLC methods were found to be rapid, precise, and accurate. Statistically, there was no significant difference between the proposed UVDS and HPLC methods. The enantiomeric separation of SB was obtained on an alpha-1-acid glycoprotein column. The R- and S-sibutramine were eluted in < 5 min with baseline separation of the chromatographic peaks (alpha = 1.9 and resolution = 1.9).