Spectrophotometric methods for the determination of tamoxifen citrate.
Three simple and sensitive spectrophotometric methods for the determination of tamoxifen citrate have been developed. They are based on the formation of an ion-association complex between the drug and a dye, Erioglaucine A, which is extractable into chloroform and has an absorption maximum at 625 nm (method A), oxidation with excess potassium permanganate and the determination of unconsumed permanganate using Fast Green FCF (method B), or by the formation of a coloured cobalt thiocyante coordination complex which is extracted into benzene and measured at 635 nm (method C). Beer's law limits for methods A, B, and C are 0.5-3.0 mug ml(-1), 1.0-6.0 mug ml(-1) and 100-500 mug ml(-1), respectively. No interference was observed from tableting additives and the applicability of the methods was examined by analysing tablets containing tamoxifen. The quantities determined were 99.0-100.03% of the exptected values.
First Derivative Spectrophotometric and Colourimetric Determination of Non-Steroidal Antiestrogens
Abstract Three methods have been described for the determination of clomiphene citrate and tamoxifen citrate. The first is based on using the first derivative spectra of UV absorption spectra. The second is based on the formation of colored ionpair compounds between the drugs and methyl orange in chloroform and measure the absorbance at 420 nm. The third is based on the reaction of the drugs with citric acid/acetic anhydride reagent and measure the absorbance at 605 nm. The proposed methods are applied for determination of the drugs in tablets. Compared with the pharmacopoeial methods, the proposed methods gave equally accurate (t-test) and precise (f-test) results. The proposed methods are selective and more sensitive than the pharmacopoeial methods.
Target of inhibition by the anti-lipogenic antibiotic cerulenin of sterol synthesis in yeast.
Abstract The antibiotic cerulenin inhibited the incorporation of 14 C-acetyl-CoA by 67% at a concentration of 9 × 10 −6 M but not that of 14 C-HMG-CoA into the non-saponifiable fraction in a cell-free extract of Saccharomyces cerevisiae . Cerulenin markedly inhibited the activity of partially purified HMG-CoA synthase. No inhibition of acetoacetyl-CoA thiolase activity was observed in the same preparation of HMG-CoA synthase. Therefore, cerulenin inhibition of overall sterol synthesis may be accounted for by the specific inhibition of HMG-CoA synthase activity.