s Levosimendan at doses 0.1-0.2 microg x kg(-1) x min(-1) did not induce hypotension or ischaemia and reduced the risk of worsening heart failure and death in patients with left ventricular failure complicating acute myocardial infarction.

Here, we suggest a theoretical approach to investigations of sorption kinetics based on determination of intrinsic characteristics of heterogeneous sorbents (affinity, quantity, and distribution of the sorption sites in the space of constants of sorption and desorption rates, distribution of the adsorbate on sorption sites at any arbitrary time, and the theoretical sorption isotherm) via calculation of the rate constant distribution (RCD) functions using experimental data obtained by the batch method. The effect of random errors in the experimental data on the stability of the calculated parameters was evaluated using simulation modeling that enables one to reduce time-and labor-consuming experimental procedures without loss in the reliability of sorbent characteristics. The applicability of the suggested approach to real experimental data was demonstrated on the sorption of transition metal ions on supermacroporous polyethylenimine cryogels. We have also shown how experimental conditions in the kinetics batch test affect determination of the sorption and desorption rates and calculation of the theoretical isotherm and how they can be optimized to yield reliable parameters to predict performance of supermacroporous monolith under dynamic conditions.

Here we address the problem of what we can expect from investigations of sorption kinetics on cryogel beads in batch. Does macroporosity of beads indeed help eliminate diffusion limitations under static sorption conditions? Are sorption rate constants calculated using phenomenological kinetic models helpful for predicting sorption properties under dynamic conditions? Applying the rate constants distribution (RCD) model to kinetic curves of Cu(II) ions sorption on polyethyleneimine (PEI) cryogel and gel beads and fines, we have shown that diffusion limitations in highly swollen beads are very important and result in at least ten-fold underestimation of the sorption rate constants. To account for intraparticle diffusion, we have developed the RCD-diffusion model, which yields “intrinsic” kinetic parameters for the sorbents, even if diffusion limitations were important in kinetic experiments. We have shown that introduction of a new variable—characteristic diffusion time—to the RCD model significantly improved the reliability of sorption kinetic parameters and allowed prediction of the minimal residence time in column required for efficient uptake of the adsorbate under dynamic conditions. The minimal residence time determined from kinetic curves simulated using the RCD-diffusion model was in good agreement with experimental data on breakthrough curves of Cu(II) ion sorption on monolith PEI cryogel at different flow rates.

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