Determination of estredox, a compound with sustained estradiol function, and its impurity profile by HPLC.

The HPLC methods described here for the assay and purity test of Estredox (E2CDS), a molecule with a redox-based, brain-targeted chemical delivery system for estradiol, allow reliable conclusions to be made on the potency and purity of API and E2CDS/HPCD complex samples. Extensive work was done to isolate and characterize the major, potential contaminants, and ensure the required stability of solutions of E2CDS, an inherently labile compound by design. Both the sample solvent and the eluent were thoroughly tested to avoid unwanted changes in sample solutions during analyses. The 12 minute isocratic assay method at 220 or 360 nm is simple, well-founded, highly precise and accurate. Purity profiling of E2CDS raised several problems in detection, stability and accuracy, owing to the fact that the pattern of the UV spectra and the stability of the compound and those of the potential contaminants often differed greatly. As a result of meticulous analysis of the UV spectra and the factors influencing the behaviour, in solution, of the compounds concerned, the 20 minute gradient method developed for the purity test, at 220 nm, of E2CDS and E2CDS/HPCD complex samples has proved to be a reliable means of adequately resolving 15-20 peaks of known and unknown compounds, and establishing the purity of various E2CDS samples. Sample impurity can be expressed as area % at 220 nm, and/or as approximate w/w % (if needed), since the relative response factors, at 220 nm, of the 6 major, potential contaminants have also been determined.

Whole-body autoradiography and quantitative organ-level distribution study of deramciclane in rats.

The distribution of 3H-labelled deramciclane (EGIS-3886), a new 5-HT2 antagonist with anxiolytic activity, has been investigated by whole-body autoradiography and quantitative organ-level determination after intravenous and oral administration to male and female rats at a dose of 3 mg kg(-1). Pregnant dams were also studied, but by autoradiography only. In the autoradiographic study 32 organs were investigated, while in the quantitative organ-level study the radioactivity in 15 organs were determined. There are no sex differences in the distribution of deramciclane, absorption is rapid, elimination is comparatively fast, no specific organ is targeted, and the accumulation of the compound is very unlikely. Penetration of the blood-brain barrier was complete and extremely fast, a very important feature of a potential anxiolytic drug. There is no penetration of the foetus in pregnant dams. The study demonstrated that deramciclane has advantageous pharmacokinetic properties in rats.

A pharmacokinetic study of JOMO-tech in rats.

A pharmacokinetic study of 99mTc labelled JOMO-tech in rats (after intravenous administration of a dose of 20 microg/kg body weight) was conducted. JOMO-tech is a heterogeneous extract derived from Nocardia opaca cell walls. An excellent fitting of the three-compartmental disposition model was achieved. The first apparent elimination half-life was very short (t1/2alpha = 0.0572 +/- 0.01383 h) followed by longer second apparent elimination half-life (t1/2beta = 0.817 +/- 0.1922 h), whereas at late post-treatment time the third apparent elimination half-life (t1/2gamma = 21.7 +/- 2.1 h) proved to be long. The peak concentration in the blood extrapolated to t = 0 yielded 32.3 +/- 7.54 ngeq/ml, this being approximately 2-fold the amount of that measured in the 5th post-treatment minute (16.84 +/- 1.447 ngeq/ml). It was determined that the main route of excretion was renal. Up to the 48th post-treatment hour, 30.03 +/- 2.788% of the dose was excreted via the urine, and only 6.71 +/- 0.973% was excreted in the feces by the 7 rats evaluated. The amount of radioactivity detected in selected tissue samples (expressed in ngeq JOMO-tech/g wet tissue) decreased in the sequence liver > kidneys > lungs > blood > plasma. In the time period studied, the highest amount of the dose was found in the liver, whereas up to the 3rd post-treatment day a practically equivalent part of the dose was found in the excreta and in the liver.