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Desirability Function (desirability + function)
Selected AbstractsDual CD system-modified MEEKC method for the determination of clemastine and its impuritiesELECTROPHORESIS, Issue 19 2010Serena Orlandini Abstract A dual system of CDs was used for the first time in MEEKC with the aim of determining clemastine and its three main related impurities in both drug substances and tablets. The addition of methyl-,-cyclodextrin and heptakis(2,6-di- O -methyl)-,-cyclodextrin to the microemulsion pseudo-stationary phase was essential to increase the resolving power of the system to obtain a baseline separation among the compounds. The best microemulsion composition was identified by mixture design and the effects of the factors concentrations of CDs and voltage were investigated by a response surface study applying a Central Composite Design. In both cases, Derringer's desirability function made it possible to find the global optimum, which corresponded to the following combination: microemulsion, 89.8% 10,mM borate buffer pH 9.2, 1.5% n -heptane and 8.7% of SDS/n -butanol in 1:2 ratio; 18,mM methyl-,-cyclodextrin, 38,mM heptakis(2,6-di- O -methyl)-,-cyclodextrin, 17,kV. By applying these conditions, the separation was completed in about 5.5,min. The method was validated following International Conference on Harmonisation guidelines and was applied to a real sample of clemastine tablets. [source] Improvement of the in vitro Digestible Iron and Zinc Content of Okra (Hibiscus esculentus L.) Sauce Widely Consumed in Sahelian AfricaJOURNAL OF FOOD SCIENCE, Issue 2 2007Sylvie Avallone ABSTRACT:, The effects of the formulation (okra, fish, soumbala, extract of wood ash) and cooking time of okra sauce on total iron and zinc content and on their in vitro digestibility were evaluated following a Doehlert uniform shell design with 5 factors and 33 trials. Cooking time had no significant effect on in vitro digestible iron and zinc content, whereas formulation did. Each ingredient had a specific effect. Extract of wood ash, which is a source of soluble and digestible iron and zinc, is a good way of increasing the digestible mineral content of the dish. Okra, the main ingredient in this sauce, has a negative effect and should be added in moderate quantities (< 37.7% of the DM of the sauce). An optimization using the desirability function allows us to identify the optimal recipe that enabled the quantity of digestible iron to be doubled and the quantity of digestible zinc to be increased by one third. This recipe calls for a mixture of 37.7% okra, 26.3% dried fish, 18.5% soumbala, and 3.7% extract of wood ash cooked for 25 min. [source] Quality by design: Optimization of a liquid filled pH-responsive macroparticles using Draper-Lin composite designJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 7 2009Hasan Rafati Abstract In this study, pH responsive macroparticles incorporating peppermint oil (PO) were prepared using a simple emulsification/polymer precipitation technique. The formulations were examined for their properties and the desired quality was then achieved using a quality by design (QBD) approach. For this purpose, a Draper-Lin small composite design study was employed in order to investigate the effect of four independent variables, including the PO to water ratio, the concentration of pH sensitive polymer (hydroxypropyl methylcellulose phthalate), acid and plasticizer concentrations, on the encapsulation efficiency and PO loading. The analysis of variance showed that the polymer concentration was the most important variable on encapsulation efficiency (p,<,0.05). The multiple regression analysis of the results led to equations that adequately described the influence of the independent variables on the selected responses. Furthermore, the desirability function was employed as an effective tool for transforming each response separately and encompassing all of these responses in an overall desirability function for global optimization of the encapsulation process. The optimized macroparticles were predicted to yield 93.4% encapsulation efficiency and 72.8% PO loading, which were remarkably close to the experimental values of 89.2% and 69.5%, consequently. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:2401,2411, 2009 [source] Influence of chitosan crosslinking on bitterness of mefloquine hydrochloride microparticles using central composite designJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 2 2009Punit P. Shah Abstract The present work examines the influence of various process and product parameters on mefloquine hydrochloride (MFL) entrapped in crosslinked chitosan microparticles for masking the bitterness. A central composite design (CCD) was employed to investigate the effect of three process and product variables, namely amount of MFL, chitosan and sodium hydroxide (crosslinking agent) on the incorporation efficiency, particle size, drug release at pH 6.8 and bitterness score. The microparticles were prepared by ionotropic gelation method, with a hardening time of 60 min. The optimum condition for process and product variables was evaluated using desirability function. The model is further cross validated for bias. The optimized microparticles were characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. Bitterness score was evaluated by human gustatory sensation test. Multiple linear regression analysis revealed that the crosslinking of chitosan significantly affects incorporation efficiency, particle size, drug release and bitterness score. The bitterness score was decreased to zero compared to 3+ of pure MFL. It can be inferred that the proposed methodology can be used to prepare MFL microparticles for bitter taste masking. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:690,703, 2009 [source] Hydrophilic interaction LC of peptides: Columns comparison and clusteringJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6-7 2010Sylvia Van Dorpe Abstract A wide variety of hydrophilic interaction chromatography (HILIC) stationary phase surface chemistries are currently available. Although their selectivity can be considerably different, column comparison or clustering using peptides is limited. In this study, ten pharmaceutically relevant model peptides are analyzed on seven different HILIC columns (bare silica, amide, poly-hydroxyethyl aspartamide, diol and zwitterionic) for the evaluation of their performance and classification. The responses examined include single and multiple responses: plate number, asymmetry factor, LOD, geometric mean resolution, resolution product, time corrected resolution product, peak capacity and chromatographic response function. Column classification was performed using hierarchical clustering and principal component analysis. Moreover, the overall performance quality of the HILIC columns was compared using a linear desirability function. Hierarchical clustering and principal component analysis showed consistent clusters. The zwitterionic phase was clustered apart from the other HILIC columns and both poly-aspartamide columns were clustered together. In addition, the two bare silica phases represent two different clusters, and thus different selectivities. Overall, the responses showed the best performance for one of the bare silica columns (Alltima-Alltech), followed by the zwitterionic phase (ZIC)-HILIC. Thus, these columns, belonging to different clusters, were found to be the best performing systems in pharmaceutical peptide analysis for the selected peptide set. [source] Robust optimization for multiple responses using response surface methodologyAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 2 2010Zhen He Abstract Typically in the analysis of industrial data for product/process optimization, there are many response variables that are under investigation at the same time. Robustness is also an important concept in industrial optimization. Here, robustness means that the responses are not sensitive to the small changes of the input variables. However, most of the recent work in industrial optimization has not dealt with robustness, and most practitioners follow up optimization calculations without consideration for robustness. This paper presents a strategy for dealing with robustness and optimization simultaneously for multiple responses. In this paper, we propose a robustness desirability function distinguished from the optimization desirability function and also propose an overall desirability function approach, which makes balance between robustness and optimization for multiple response problems. Simplex search method is used to search for the most robust optimal point in the feasible operating region. Finally, the proposed strategy is illustrated with an example from the literature. Copyright © 2009 John Wiley & Sons, Ltd. [source] Experimental Investigation and Modeling Approach of the Phenylacetonitrile Alkylation Process in a MicroreactorCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2009E. S. Borovinskaya Abstract The application of microreaction technology has the potential to intensify chemical processes. It is therefore of great interest to investigate the operating efficiency of a multiphase process such as the alkylation of phenylacetonitrile in a microreactor and to compare the performance to a batch reactor. The undeniable advantages of continuous microreactor systems for this process were demonstrated. Furthermore, the influence of the organic to aqueous phase ratio in the microreactor was investigated. A model of the reaction course was formulated based on experimental data. This model was used in the analysis and modeling of the alkylation process in a microreactor and found to be adequate. The optimal microreactor performance conditions were determined using the numerical optimization technique (Harrington's desirability function) and confirmed by experiments. [source] OPTIMIZATION OF NEW FLOUR IMPROVER MIXING FORMULA BY SURFACE RESPONSE METHODOLOGYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2010RAOUDHA ELLOUZE GHORBEL ABSTRACT In the present study, we search to improve the viscoelastic properties of wheat flour characterized by a low bread-making quality. Six regulators were tested: broad bean flour, gluten, monodiglyceride (MDG), ascorbic acid, sodium alginate and a mixture of amylase and xylanase. A hybrid design was carried out in order to study the effect of these regulators on the alveographic properties of wheat flour dough. Two alveographic responses (W: deformation energy and P/L: elasticity-to-extensibility ratio) were studied and simultaneously optimized via the desirability functions. An optimal mixture, containing 13.17 g/kg of broad bean flour, 15.13 g/kg of gluten, 0.155 g/kg of ascorbic acid, 3.875 g/kg of MDG, 2.75 g/kg of sodium alginate and 0.3 g/kg of enzyme mixture, was obtained and tested in a Tunisian flour. It led to a dough characterized by a W = 274 × 10,4 J and P/L = 0.74 versus 191 × 10,4 J and 0.40, respectively, for the Tunisian flour without improvers. PRACTICAL APPLICATIONS In this work, we developed a new flour improver mixing formula intended to be used with wheat flour characterized by a low bread-making quality. This improver mixture is in powder form and contains 13.17 g of broad bean flour, 15.13 g of gluten, 0.155 g of ascorbic acid, 3.875 g of monodiglyceride, 2.75 g of sodium alginate and 0.3 g of enzyme mixture per kilogram of wheat flour. The incorporation of this improver mixture in low bread-making quality wheatflour leads to an increase of its deformation energy (W) of about 43% and produces large volume bread. [source] | ||||||||||