Clinker burning process has a decisive influence on energy consumption and the cost of cement production. A new problem is to use the process of decarbonization of alternative fuels from waste. These issues are particularly important in the introduction of a two-stage combustion of fuel in a rotary kiln without the typical reactor-decarbonizator. This work presents results of numerical studies on thermal-hydraulic phenomena in the riser chamber, which will be designed to burn fuel in the system where combustion air is supplied separately from the clinker cooler. The mathematical model is based on a combination of two methods of motion description: Euler description for the gas phase and Lagrange description for particles. Heat transfer between particles of raw material and gas was added to the numerical calculations. The main aim of the research was finding the correct fractional distribution of particles. For assumed particle distribution on the first stage of work, authors noted that all particles were carried away by the upper outlet to the preheater tower, what is not corresponding to the results of experimental studies. The obtained results of calculations can be the basis for further optimization of the design and operating conditions in the riser chamber with the implementation of the system. Keywords: Two-phase flow; Precalcination; Particle distribution; CFD
Objective:
The aim of the presented comparative study was to evaluate the bioavailability of clopidogrel (CAS 113665-84-2) formulations containing clopidogrel bisulfate (CAS 135046-48-9, CBS) 75 mg based on the parent compound (CBS) and its metabolite SR 26334 ?clopidogrel carboxylic acid (CAS 144457-28-3, CCA) determination.
Methods:
This paper presents the results of a comparative, randomized, two-way cross-over study on 48 healthy male volunteers assessing the bioequivalence of two products of clopidogrel 75mg in form of film-coated tablets. In each of the two periods, separated by a 7-day washout period, a single dose of 150 mg (2 2 75mg) of test and reference preparations was administered under fasting condition. Nineteen blood samples for determination of CBS and CCA were collected up to 48 h post dose. The CBS and CCA concentrations were quantified by a selective ultra performance liquid chromatographic-tandem mass spectrometric (UPLC-MS/MS) method.
Pharmacokinetic parameters such as AUCinf, AUCt, Cmax, t max, t 1/2 were estimated using a non-compartmental model. Bioequivalence evaluation and calculation of CI were performed for clopidogrel and its metabolite by two one-sided t-test procedures by Schuirmann.
Results:
In case of CCA the values of pharmacokinetic parameters were similar for the two products (test vs reference): AUCinf: 15 773 vs. 15 691 ng ? h/mL, AUCt : 15 462 vs. 15 315 ng ? h/mL, C max : 4919 vs. 4699 ng/mL, t max : 0.84 vs. 0.93 h, t 1/2: 7.92 vs. 8.41 h. Points of estimation of the ratios test/reference were near to 100% and CI in ranges 80?125% were fulfilled for all tested parameters.
Pharmacokinetic parameters values of CBS were: AUCinf : 1.96 vs. 1.84 ng ? h/mL (test vs reference), AUCt : 1.91 vs. 1.81 ng ? h/mL, C max 1.44 vs. 1.52 ng/mL, t max : 0.90 vs. 0.99 h, t1/2: 0.74 vs. 0.57 h. The parametric 90%-confidence interval (CI) was in the range of 80?125% for AUCt ratio and AUCinf ratio. The CI range of C max fulfilled the widened range of 75?133 % (according to the study protocol). Unfortunately, the very high variability of pharmacokinetic parameters (over 50%) contributed to low power of the test.
Conclusions:
Measurement of CBS concentrations should not be a reliable one for the bioequivalence assessment, due to very low concentrations, very small and variable values of AUC and high intra-subject variability. Thus, bioequivalence evaluation should be based on CCA determination. In the presented study evaluation based on CCA unequivocally and with the proper power confirmed the bioequivalence between the investigated clopidogrel products.
In this study, we first demonstrated the effect of CYP2D6 polymorphism on pharmacokinetics of tolperisone in Caucasian subjects. The contribution of CYP2C19 enzyme seems to be less important.
Rajskie "drzewo poznania dobra i zła" w literaturze wczesnochrześcijańskiej "The tree of knowledge of good and evil" of early christian literature Słowa kluczowe: raj, drzewo poznania dobra i zła, grzech. Księga Rodzaju.
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