AUC process

Ammonium uranyl carbonate (AUC) process This process was developed in the 1960 s in the Federal Republic of Germany. It comprises the simultaneous feeding of uranium(Vl) fluoride, carbon dioxide and ammonia into an aqueous ammonium carbonate solution at 70°C, whereupon tetra-ammonium tricarbonato-dioxo-uranate (ammonium uranyl carbonate) precipitates out ... 

The UO2 powder obtained by this process is readily granulated and sintered, without the addition of binders, to controlled densities. Pore size distribution can be controlled by addition of UsOg. The pellets have high stability (no further densification takes place during operation). The pellet density in the French (dci) process is controlled by the cold compaction pressure in forming the green compacts. The ammonium uranyl carbonate (AUC) process in Germany (KWU) produces UO2 powder that flows freely as... 

Another production method used for the conversion of the UF-a to UO2 is the ammonium uranyl carbonate (AUC) process. The form of the AUC precipitate is probably (NHa) [UOz(COa)3]s. This compound is calcined to UOior UjOa, which is then reduced to UOa. 

It can readily be seen from this example that the contributions of the extrapolated areas to the total areas are relatively more important for the higher order moments. In this example, the contributions are 28, 61 and 72% for AUC, AUMC and AUSC, respectively. Because of this effect, the applicability of the statistical moment theory is somewhat limited by the precision with which plasma concentrations can be observed. The method also requires a careful design of the sampling process, such that both the peak and the downslope of the curve are sufficiently covered. 

AUC [Ammonium uranyl carbonate] A process for converting uranium hexafluoride into uranium dioxide for use as a nuclear reactor fuel. The hexafluoride vapor, together with carbon dioxide and ammonia, are passed into aqueous ammonium carbonate at 70°C, precipitating ammonium uranyl carbonate ... 

This reaction has also opened a rapid access to various polycyclic compounds, as illustrated by the transformation of a mixture of diastereomers 373 into tricyclic compound 374 as a single diastereomer, through a completely stereo-convergent process (Scheme 92). Interesting entries into the syntheses of carane family natural products have also been disclosed by Ftirstner with AuC 331 and by Marco-Contelles with PtCl2.332... 

The expected Cmax and AUC for each of the profiles are listed in Table 3. The profiles are predicted to show an acceptable range of Cmax values with around 20% difference between the fast and medium formulations and between the medium and slow formulations. The predicted differences in AUC are only related to the slightly different content of the three formulations, reflected in the Finf values (100% for the fast formulation and 102% for the other formulations). Normally, AUC is not expected to be rate-dependent unless there is some non-linear process involved in the disposition of the drug or drug release or absorption is very slow compared to gastrointestinal transit time. Given the predicted Cmax differences, these three formulations are appropriate choices for an IVIVC study as they show acceptable in vitro and predicted in vivo differences. 

When compared with direct compression results, the dry granulation processes enhance the flow of the powder and decrease the variability of the AUC, the major response. Nevertheless, this variability and the variability of the drug dissolved at 8 h (T7) are greater than the fixed optimal values, particularly for the compaction processes. From the results it is seen that the wet granulation process gave a powder presenting an adequate or better result than the other processes ... 

As the AUC value is almost the same, may the P parameter of the Weibull function be used for evaluating the variability between tablets and between processes ... 

Fig. 3 illustrates the effect of the process on the same formula and for near AUC values. The wet granulation release profile exhibits a marked sigmoid aspect owing to the high P value. 

---