For formulas 11 and 12, growths were observed only for Aspergillus niger. This can comfort the hypothesis that this mold is more sensitive to ethanol than it is to pH and glycerin. Only the formulas at 4% of ethanol presented contamination by this mold. Data are not available with Design Expert? because of lack of values. Contaminations at D7 decreased at D14 until D28 but two remained still important. Indeed, formulas 6 and 11 were still contaminated by Aspergillus brasiliensis. The main reason for this was the drop of pH from 11 to 7 as well as the low level of ethanol. The concentration of glycerin had no Alectinib datasheet
influence in that case. Data are not available with Design Expert? because of the lack of values. Therefore, aw was not a distributed parameter, as it could not be possible to monitor. Therefore, this factor was evaluated at the end of the formulation and was thus considered as a specific response factor. The concentration of ethanol, glycerin and the pH could influence this factor. Ergo, the relation between these parameters and the aw was evaluated Gemcitabine
with Design Expert?. The R-squared value was significant (R2?=?0,9927) and the ANOVA analysis showed that the system was highly significant given the P-value of <?0.0001. The residual analysis (Fig.?3) showed a good uniformity of points with the ovoid shape of the set of points. The analysis of the error distribution (lack of fit test) showed no significance in terms of residual errors when compared with outright errors. This proved that the model was properly adapted. In Fig.?3, the red dot is the negative residual of greater amplitude. It is usual that the point minimum and maximum of a series does not fit the straight line. The analysis model for the aw was very significant and therefore it was possible to establish a linear relationship between the four factors. The relation between aw and the three parameters can be modeled by the following mathematical equation: Finally, it was possible to establish the first elements of a predictive microbiology model as in the food industry [12, 14, 15, 18] but a further study is needed to refine the data. Hereafter is the Table?7 that summarizes the global data: For combined parameters, only pH and ethanol <a href="http://www.selleckchem.com/epigenetic-reader-domain.html
">selleck inhibitor showed a significant effect for A.?niger at D0, especially with a high concentration of ethanol and extreme pH. This article showed a different approach to the study of the challenge test in relation to previous works. Indeed, our experimental design was based on the variation of several factors without preservatives unlike previous studies, which studied different combinations of preservatives in the formula.  In addition, this report discusses new parameters (as pH, aw, ethanol) of variations from other studies conducted to date.  Thanks to an experimental design approach using 16 formulations, the effectiveness of the three selected parameters was evaluated.