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Acta Biologica Hungarica
Authors: A. Waśko, Monika Kordowska-Wiater, M. Podleśny, Magdalena Polak-Berecka, Z. Targoński, and Agnieszka Kubik-Komar

Ghanem, N. B., Yusef, H. H., Mahrouse, H. K. (2000) Production of Aspergillus terreus xylanase in solid state cultures: application of the Plackett-Burman experimental design to evaluate nutritional requirements. Biores. Technol. 73 , 113

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Acta Chromatographica
Authors: M. Mašković, B. Jančić-Stojanović, A. Malenović, D. Ivanović, and M. Medenica

Summary

Robustness testing is an important part of method validation. Many ideas on robustness testing can be found in the literature, but the most useful approach is application of experimental design. In the work discussed in this paper, Plackett-Burman design was used for robustness testing of an LC method. Robustness was assessed for a previously validated method developed for chromatographic analysis of perindopril tert-butylamine and its impurities. Eleven factors (seven real and four dummies) in twelve experiments were examined. Robustness was assessed by graphical (half-normal probability plots and Pareto charts) and statistical (t-test) methods. For estimation of the standard error of effect (necessary for t-test estimation) calculations based on negligible effects and Dong's algorithm were used at the significance levels α= 0.05 and α = 0.01. In this way the effect of the factors was completely defined and, furthermore, nonsignificant intervals for significant variables were calculated. Finally, on the basis of the worst-case situation, system-suitability tests were performed and acceptance limits for certain values were calculated.

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. , Abou-Elela , G. M. : Antagonistic effect of marine Nocardia brasiliensis against the fish pathogen Vibrio damsela : Application of Plackett-Burman experimental design to evaluate factors affecting the production of the antibacterial agent . IJOO 1

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performed using MODDE® 12.1 software. Design of experiment Plackett-Burman design (PBD) with five variables was used for screening the significant and non-significant variables. This design was selected based on the small number of experiments required. The

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Six isolates with phenol degrading ability were obtained from marine sediments by enrichment procedures and an isolate, AM4, was identified as Alcaligenes sp. by 16S rDNA sequencing. The Plackett-Burman design was applied to estimate the significance of culture medium components and conditions for phenol degradation by Alcaligenes sp. AM4. The resulting medium formula which was predicted to be near optimal was: phenol conc. (240 μg/ml), culture volume (37.5 ml), inoculum’s size (0.15 ml), NH4SO4 (0.5 g/l), K2HPO4 (0.75 g/l), KH2PO4 (0.75 g/l), MgSO4 (0.3 g/l) and NaCl (0.25 g/l). Scanning electron microscopy was applied to cells exposed to phenol, and a larger cell size was detected, resulting in a reduced cell surface. This relative reduction of the cell surface represents a cellular mechanism to reduce the toxic effect of this environmental stress factor.

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A gradient reversed phase high-performance liquid chromatography (RP-HPLC) method with ultraviolet (UV) detection to analyze hydrochlorothiazide (HCT) and valsartan (VS) simultaneously in a tablet formulation during forced degradation studies was developed. This method was validated using a novel approach, namely, the accuracy profile or total errors approach. The robustness of the method was evaluated using a Plackett-Burman design for eight factors. The algorithm of Dong was applied to determine the significant factor effects. The validation results showed that the method is precise (RSD: 1.14% for HCT and 0.43% for VS) and accurate (mean recovery: 99.90% for HCT and 99.98% for VS). On the other hand, the results of the robustness study showed that the type of column was the important factor which affects a number of responses, namely, the asymmetry factor (AF), retention time (RT), and resolution (RS). However, the assay results were not affected; therefore, the method can be considered robust. Finally, the method was applied to study the stability of HCT and VS under forced conditions. Significant results were obtained with basic hydrolysis, oxidation, and thermal stress, while the accelerated and acidic conditions did not affect the stability of HCT or VS.

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, N. B., Mabrouk, M. E., Sabry, S. A., El-Badan, D. E. (2005) Degradation of polyesters by a novel marine Nocardiopsis aegyptia sp. nov.: application of Plackett-Burman experimental design for the improvement of PHB depolymerase activity. J

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., Destain, J., Razafindralambo, H., Paquot, M., Pauw, E. D. and Thonart, P. (1999): Optimization of biosurfactant lipopeptide production from Bacillus subtilis S499 by Plackett-Burman Design. App

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application of the RSM, the critical parameters affecting the method must first be selected by the screening study. Since the sample size is traditionally small, the interaction effects are completely enveloped in the main effects. Therefore, the Plackett–Burman

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