Effects of Tryptophan on the Polymorphic Transformation of Calcium Carbonate: Central Composite Design, Characterization, Kinetics, and Thermodynamics

The objectives of this study were to: (i) determine the effects of tryptophan on the polymorphic phase transformation of CaCO3, (ii) investigate the thermal degradation characteristics of CaCO3 in terms of kinetics and thermodynamics using the Coats–Redfern method, and (iii) assess the influence of the experimental conditions on the vaterite composition of CaCO3 using response surface methodology based on central composite design. First, the CaCO3 crystals were prepared and analyzed using XRD, FTIR, SEM, BET, AFM, and zeta potential analysis. Based on the characterization results, the shape of the CaCO3 crystals changed from smooth cubic calcite crystals to porous irregular spherical-like vaterite crystals with increasing tryptophan concentration. Meanwhile, the kinetic results showed that the thermal degradation of CaCO3 followed the shrinkage geometrical spherical mechanism, R3 and the average activation energy was 224.6 kJ/mol. According to the results of the experimental design, the tryptophan concentration was the most influential variable affecting the relative fraction of vaterite in the produced crystals. It can be concluded that tryptophan is important for better understanding and controlling the polymorph, size, and morphology of CaCO3 crystals.

Download Full-text

Central Composite Design for Response Surface Methodology and Its Application in Pharmacy

10.5772/intechopen.95835 ◽

2021 ◽

Author(s):

Sankha Bhattacharya

Keyword(s):

Central Composite Design ◽

Response Surface ◽

Response Surface Model ◽

Fractional Factorial ◽

Surface Model ◽

Experimental Conditions ◽

Design Models ◽

Central Composite

The central composite design is the most commonly used fractional factorial design used in the response surface model. In this design, the center points are augmented with a group of axial points called star points. With this design, quickly first-order and second-order terms can be estimated. In this book chapter, different types of central composite design and their significance in various experimental design were clearly explained. Nevertheless, a calculation based on alpha (α) determination and axial points were clearly described. This book chapter also amalgamates recently incepted central composite design models in various experimental conditions. Finally, one case study was also discussed to understand the actual inside of the central composite design.

Download Full-text

Development and optimization of solid lipid nanoparticles of amikacin by central composite design

Journal of Liposome Research ◽

10.1080/08982100903103904 ◽

2009 ◽

Vol 00 (00) ◽

pp. 090721051030036-8

Author(s):

Jaleh Varshosaz ◽

Solmaz Ghaffari ◽

Mohammad Reza Khoshayand ◽

Fatemeh Atyabi ◽

Shirzad Azarmi ◽

...

Keyword(s):

Central Composite Design ◽

Solid Lipid Nanoparticles ◽

Lipid Nanoparticles ◽

Solid Lipid ◽

Central Composite

Download Full-text

Central Composite Design for Optimization of Chromium (VI) Removal from Aqueous Solution Using Low Cost Adsorbent

i-manager’s Journal on Future Engineering and Technology ◽

10.26634/jfet.11.1.3654 ◽

2015 ◽

Vol 11 (1) ◽

pp. 1-6

Author(s):

D. Krishna ◽

◽

D.V. Padma ◽

Keyword(s):

Aqueous Solution ◽

Central Composite Design ◽

Low Cost ◽

Chromium Vi ◽

Central Composite

Download Full-text

Selected illustrations of response surface method. Central composite design

10.3403/30242021u ◽

2016 ◽

Keyword(s):

Central Composite Design ◽

Response Surface ◽

Response Surface Method ◽

Surface Method ◽

Central Composite

Download Full-text

Formulation Design and Optimization of Repaglinide Solid Dispersions by Central Composite Design

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2018.11.6.7 ◽

2018 ◽

Vol 11 (6) ◽

pp. 4337-4348

Author(s):

Bhikshapathi D. V. R. N. ◽

Srinivas I

Keyword(s):

Central Composite Design ◽

Dissolution Rate ◽

Solid Dispersion ◽

Solid Dispersions ◽

Solvent Evaporation ◽

Release Mechanism ◽

Solvent Evaporation Method ◽

Onset Of Action ◽

Evaporation Method ◽

Central Composite

Repaglinide is a pharmaceutical drug used for the treatment of type II diabetes mellitus, it is characterized with poor solubility which limits its absorption and dissolution rate and delays onset of action. In the present study, immediate release solid dispersion of repaglinide was formulated by solvent evaporation technique. Repaglinide solid dispersions were prepared using PEG 8000, Pluronic F 127 and Gelucire 44/14 by solvent evaporation method. A 3-factor, 3-level central composite design employed to study the effect of each independent variable on dependent variables. FTIR studies revealed that no drug excipient interaction takes place. From powder X-ray diffraction (p-XRD) and by scanning electron microscopy (SEM) studies it was evident that polymorphic form of repaglinide has been converted into an amorphous form from crystalline within the solid dispersion formulation. The correlation coefficient showed that the release profile followed Higuchi model anomalous behavior and hence release mechanism was indicative of diffusion. The obtained results suggested that developed solid dispersion by solvent evaporation method might be an efficacious approach for enhancing the solubility and dissolution rate of repaglinide.

Download Full-text