SIMPLE AND RAPID METHOD FOR THE SIMULTANEOUS ANALYSIS OF TAMOXIFEN, ENDOXIFEN, AND 4-HYDROXYTAMOXIFEN IN DRIED BLOOD SPOT USING LIQUID CHROMATOGRAPHY–TANDEM MASS SPECTROMETRY

Objective: Tamoxifen (TAM) is a hormonal therapy that is clinically proven to reduce breast cancer recurrence by blocking estrogen receptor, mainly through its active metabolites, 4-hydroxytamoxifen (4HT) and endoxifen (END), which have a higher affinity to ER than TAM itself. The objective of the present study was to develop and validate simple and rapid LC-MS/MS method for analysis TAM and its metabolites simultaneously in dried blood spot (DBS) sample for monitoring studies purposes. Methods: Optimization was done by evaluating several parameters that affect the efficiency of DBS preparation, such as blood spot volume, drying time and extraction method from the DBS paper. The effectiveness of chromatographic conditions was also optimized by varying flow rate, mobile phase combination and gradient. Clomiphene was used as the internal standard. Results: The result showed that preparation of 20 µl blood spot volume with 120 min of drying time and 25 min of extraction time using 1 ml methanol was the most efficient condition and also fulfilled recovery and matrix effect requirement according to FDA and EMA guidelines. The separation was performed on UPLC Class BEH C18 using formic acid 0.1%-formic acid 0.1% in acetonitrile (35:65) as the mobile phase in isocratic mode at 0.25 ml/min with a total analysis time of 4 min. Conclusion: This method has successfully fulfilled all validation requirements referring to EMA and FDA guidelines.

Potato bruise spot sensitivity dependence on regimes of cultivation

Potato tuber bruising was simulated by impact pendulum at temperature 7°C. Two varieties (Agria and Samantana) cultivated under five different regimes were tested one month and/or five months after harvest. The regimes of cultivation differ by fertilising and/or irrigation. The obtained black spots were measured carefully to obtain detailed shape and volume. The obtained results are discussed in relation to tuber anatomy (vascular ring), regime of cultivation and mean tuber density. It is shown that contrary to bruising in fruits the black spots had maximum diameter not close to the surface but close the vascular ring. The relation between spot volume and the mean tuber density seems to be variety dependent.

Approximation of bruise spot volume in pears in plots against deformation parameters

Pears of different varieties were compressed between two flat rigid plates in loading/unloading tests. The bruise spots appearing after room temperature incubation were analysed manually, and bruise spot volumes were determined. The main parts of the paper discuss mathematical approximation of total bruise volume versus two deformation parameters defined in previous papers: hysteresis losses and degree of elasticity. The polynomial of the second order was used for this purpose, but success of this method depends on including some part of not-bruising results in the analysis. Characteristic values of hysteresis losses and degree of elasticity were used to determine the bruise index, the integral parameter, that is suitable for classifying the tested varieties as to tissue susceptibility to low-level bruising. The variety susceptibility to bruising decreased in the following order: Elektra, Erika, Vonka, Lucasova, Dicolor, Dita, Omega, Jana, Lada, Astra, Bohemica, and Delta.