Alkaloid AD Skopje

A simple methodol. for estimation of the antioxidative activity by measuring the kinetics of the homogeneous electron transfer reaction between an antioxidant and ferroceniumdimethanol cation (Fc⁺) is proposed.The method is based on the well-known regenerative E_rC' catalytic reaction scheme, where the antioxidant is catalytically oxidized by Fc⁺, which is in situ formed by the reversible oxidation of ferrocenedimethanol at glassy carbon electrode.Comparing the rate of the homogeneous oxidation of different antioxidant with the same oxidant, i.e., Fc⁺, which serves as a referent system, a more consistent comparison of the antioxidative activity can be done than comparing the heterogeneous oxidation reactions at the electrode surface.The applicability of the method is demonstrated in a comparative anal. of glutathione (GSH) and ascorbic acid (AA), the two important and widely abundant low mol. weight antioxidants, by means of cyclic voltammetry (CV), square-wave voltammetry (SWV), and chronoamperometry (CA).At physiol. conditions (pH ∼ 7) the rate of AA oxidation (∼ 10⁴ mol^-1 L s^-1) is two orders of magnitude higher than GSH (∼ 10² mol^-1 L s^-1) implying superior antioxidative activity of the former.From a methodol. point of view it is important to stress that the kinetic data estimated with CV and CA are comparable, while SWV gives much higher estimates for the catalytic rate constantsThis implies that different techniques lead to different kinetic data, which must be taken into account in estimating the antioxidative activity, as well as in comparing the kinetic data reported in the literature.

This research highlights the specificity of the new stability-indicating method developed to evaluate the impurity profile of Atorvastatin film-coated tablets. The proposed method has the ability to capture any possible changes that may occur during the stability studies over time and under different stress factors, and is selective enough to enable quality control of finished product from different suppliers of active pharmaceutical ingredient (API)/excipients.  Satisfactory critical peak resolution between specified and unspecified impurities was achieved using the fused-core shell technology and extensively endcapped diisopropyl-cyanopropylsilane stationary phase (Halo ES-CN 150 mm × 4.6 mm, 2.7 µm), with a 10 mM ammonium formate buffer pH 3.5 and acetonitrile as mobile phase. A potential worse case impurity profile was assumed by using retained samples combined with the data obtained for samples manufactured with APIs from different suppliers exposed to the forced degradation study. The mass balance for stressed samples demonstrated the stability-indicating capability of the proposed method.

thebaine (I) [115-37-7] was separated from codeine  [76-57-3] by the extraction of a mixture with various solvents such as benzene, CHCl₃, ethylene dichloride and trichloroethylene  [79-01-6] at different pHs and separating and quantitating the compounds by TLC and spectrophotometry.Trichloroethylene gave the best separation and the optimum pH was 5.4.Since I decomposes in mineral acids, HOAc was preferred during the extraction procedure.This method gives quant. results and can be used for the separation of these compounds during the isolation of opium alkaloids from poppy straw.