Specific spectrophotometric method with trifluoroacetic acid for the determination of selenium(IV) in selenitetriglycerides.

The role of selenium as an antioxidant and anticancer agent is very well documented in the literature. Selenium compound showing the highest activity as a free radicals scavenger and as an anticancer agent should contain selenium at +4 oxidation level. The synthesis of selenitetriglycerides (named selol) was carried out in the Department of Drug Analysis at Warsaw Medical University (Polish Patent 1999). Selenitetriglycerides showed a dimeric structure. In a single dose toxicity studies performed in rats, LD50 was 100 mg Se kg(-1) after oral administration of selol. The subcutaneous and intraperitoneal administration of selol showed extremely low toxicity. The aim of this work was to develop a new specific method for the determination of Se(IV) in selol. We stated that selenitetriglycerides react quantitatively with trifluoroacetic acid (TFA) in dichloromethane giving a red-coloured conjugate. However, recorded spectrum showed the maximum absorption in the wavelength 380 nm. The optimal conditions of the reaction were established, namely temperature 35 degrees C and reaction time 35 min. The reaction was proved to be specific because neither selenites nor other selol constituents react with TFA. The constructed calibration curve obeyed the Lambert-Beer law in the range of 0.1-7.4 mg ml(-1). Molar absorption coefficient is epsilon =9.46 x 10(3) l mol(-1) cm(-1) and epsilon =2.36 x 10(5) l mol(-1) cm(-1) calculated for selenium and selenitetriglyceride dimer (m.w. 1972.72), respectively. Obtained results for selenium determination were confirmed by AAS method. The developed method showed specificity and high sensitivity.

Pharmacokinetics of selol, a new agent containing selenium, in rats.

The pharmacokinetic properties of selol, a new organoselenium compound, were evaluated in rats. Each animal was given a single oral or subcutaneous dose of selol 12 mg/kg. The selenium concentration was determined in whole blood and tissues by non flame carbon furnace atomic-absorption spectrometry. The pharmacokinetic parameters Cmax and tmax differed statistically between oral (p.o.) and subcutaneous (s.c.) treatment. The selenium average peak concentrations in the blood were 494 +/- 8 ng/ml after oral and 322 +/- 5 ng/ml after subcutaneous administration. They were reached after 1.9 +/- 0.1 h and 2.4 +/- 0.1 h, respectively. For the AUC0 mean values of 1373 +/- 56 ng.h/ml (p.o.) and 1273 +/- 137 ng.h/ml (s.c.) were found. The mean residence time (MRT) was significantly longer after subcutaneous administration. Selenium distributes quickly to the main organs with prevalence to the adrenal gland. Moreover, its concentrations in the examined organ were evidently higher after subcutaneous treatment as compared to the oral route. Our data suggest that Selol may be used as a possible source of selenium for the treatment of selenium-deficient patients, particularly via the subcutaneous route.

Toxicity studies of a new selenium compound, Selol, in rats.

Selol is a new organoselenium compound synthesized in the Department of Drug Analysis, Warsaw. The general acute and cumulative toxicities of Selol were tested in rats. The compound did not display any toxic effects after parenteral administration up to 500 mg/kg-1 s.c. and 100 mg/kg-1 i.p. However, given orally it exhibited high toxicity. LD50 value after a single oral administration amounted to 100 mg/kg-1 and after administration in an increasing-dose schedule to 80 mg/kg-1. On the basis of these results the authors conclude that Selol may be converted to a more toxic product during digestion. Therefore, Selol as a source of selenium is safer given by the parenteral route.