Sylvie Chamart

Determination of 2-methyl derivatives of tamoxifen in cell culture medium using high-performance liquid chromatography and electrochemical detection

The 2-methyl derivatives of tamoxifen (2-methyltamoxifen and 2-methyl-4-hydroxytamoxifen) were extracted from a cell culture medium at pH 5.4 (Earles Minimum Essential Medium) with an internal standard (tamoxifen) on a phenyl sorbent cartridge. The compounds were then separated by high-performance liquid chromatography on a nitrile column eluted with acetonitrile-methanol-0.05 M sodium dihydrogenphosphate (19:4:11.6:69,v/v) containing 0.11 mmol/l disodium EDTA and determined by electrochemical detection at +1.1 V vs. Ag/AgCl/3 M NaCl. The absolute detection limits were 50 pg for 2-methyl-4-hydroxytamoxifen and 100 pg for tamoxifen and 2-methyltamoxifen at a sensitivity of 1 nA/V.

Adsorption of tamoxifen and 2-methyl derivatives under cell culture conditions

Abstract Adsorption of triphenylethylene compounds (tamoxifen, 4-hydroxytamoxifen and their 2-methyl derivatives) on glass and plastic surfaces was separately evaluated under specific conditions met during the preparation of solutions and their incubation. The composition of the culture medium (whether supplemented or not with serum), the material of the recipient (glass or plastic), the concentration of the drug and the substituents on the molecule dramatically affected the amount of active principle left in solution. When evaluated without cells, incubation of a less polar molecule (i.e., tamoxifen) at a low concentration (10 −8 M) in a culture medium not supplemented with serum in a plastic dish left only 10% of the initial concentration after 1 h. Under the same conditions, the more polar 4-hydroxytamoxifen had a recovery rate of 20%. Advice is given on circumventing these problems which may lead to erroneous conclusions.

Cultivation of Holarrhena floribunda for conessine production in Burkina Faso.

AbstractThe cultivation, conessine content and harvesting methodology for Holarrhena floribunda were investigated. Allometric measurements are proposed as prediction tools for estimation of trunk total productions of bark and conessine. A linear relationship found between stem diameter and bark conessine content allowed the establishment of log-log correlations between trunk circumference and trunk production of bark and conessine. Harvesting of a five years old culture by a coppicing method could be estimated at 976 kg/ha of stem bark and 7.8 kg/ha of conessine. Stems of diameter < 0.5 cm present little interest for alkaloid production and should be discarded.