Colorimetric Method for the Estimation of Ethanol in Alcoholic-Drinks

A method for estimating ethanol in alcoholic-drinks by direct reaction is presented. The method consist of color reaction of ethanol with sodium dichromate. The colorimetric quantification was based on the formation of green colored chromate ions resulting from treatment of ethanol and sodium dichromate as limiting reactant in presence of sulfuric acid and acetate buffer pH 4.3. The absorbance maxima for the ethanol was found to be 578 nm. The influence of acetate buffer pH, reaction time, and Beer’law on color development and sensitivity were investigated and optimal assay conditions established.The limits of detection and quantification for ethanol were determined to be 0.6 mg/mL and 1.9 mg/mL

Evaluation of Physical Stability of Oleogels Containing Diclofenac Diethylamine

ABSTRACT Oleogels are semisolid systems obtained with an organogelator and a hydrophobic liquid that have been investigated over the past few years and that could play an important role as dermatological bases. Recently, we have developed a formulation containing Diclofenac Diethylamine (1.16 % w/w) in two oleogel bases of Colloidal Silicon Dioxide (7.0 % w/w) in Sesame oil (CSD-SO) and another one of Colloidal Silicon Dioxide (7.5 % w/w) in Light liquid paraffin (CSD-LP). The aim of this study is to access their physical stability using different methodologies. The gels were stored at different temperatures (20 0 to 50 0 C) over a period of six months. Appearance and textural properties were assessed on each month. An accelerated test was also performed where the temperature changed between 4 0 and 40 0 C every 24 h, during 7 days. Rheological tests were also carried out as they could provide useful elements to predict stability. The textural properties of both gels were influenced by temperature. The decrease of the textural parameters, observed after storage at 40 0 C and in the cycling test, were more significant in case of CSD-LP gels. The heating/cooling cycle test provided useful information in a short period of time. The gels were quite stable at 20 0 C, being the CSD-SO gel the most stable