Description of interaction processes in agitated liquid-liquid dispersions

Coulaloglou, C.A.; Tavlarides, Lawrence L.

doi:10.1016/0009-2509(77)85023-9

Cited by 1,097 publications

(1,180 citation statements)

References 34 publications

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“…Repeating the processing or cycling resulted in a decrease in average particle size and a narrowing of the particle size distribution, after which mean particle size and standard deviation both increased as processing continued. This observation is in agreement with reports substantiating that droplet sizes are a result of breakage and coalescence and that, for systems containing relatively high percentages of oil, increasing the operative pressure does not always lead to a reduction of emulsion droplet size [11,12].…”

Section: Resultssupporting

confidence: 93%

Stability of drug-carrier emulsions containing phosphatidylcholine mixtures

Trotta

Pattarino²,

Ignoni

2002

European Journal of Pharmaceutics and Biopharmaceutics

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Lipid emulsion particles containing 10% of medium chain triglycerides were prepared using 2% w/w of a mixture 1:1 w/w of purified soya phosphatidylcholine and 2-hexanoyl phosphatidylcholine as emulsifier mixture, for use as drug carriers. The mean droplet sizes of emulsions, prepared using an Ultra Turrax or a high-pressure homogenizer, were about 288 and 158 nm, respectively, compared with 380 and 268 nm for emulsions containing lecithin, or 325 and 240 nm for those containing 6-phosphatidylcholine. The stability of the emulsions, determined by monitoring the decrease of a lipophilic marker at a specified level within the emulsion, and observing coalescence over time, was also greatly increased using the emulsifier mixture. The emulsion stability did not notably change in the presence of a model destabilizing drug, indomethacin. The use of a second hydrophilic surfactant to adjust the packing properties of the lecithin at the oil-water interface provided an increase in the stability of lipid emulsions, and this may be of importance in the formulation of drug delivery systems. q

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Section: Resultssupporting

confidence: 93%

Stability of drug-carrier emulsions containing phosphatidylcholine mixtures

Trotta

Pattarino²,

Ignoni

2002

European Journal of Pharmaceutics and Biopharmaceutics

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“…The detailed description of the PBE, the sub model implementation and numerical parameter definition is reported in Kamp et al (2012). As this article focusses on the coalescence efficiency, the other sub models of collision frequency and drop breakage which are necessary to solve the PBE were taken from the frequently used model of Coulaloglou and Tavlarides (1977). The coalescence efficiency sub models of Coulaloglou and Tavlarides (1977) and Tobin and Ramkrishna (1999) were compared with regard to the description of the coalescence inhibition due to electrostatic effects.…”

Section: Numerical Investigations and Parameter Estimationmentioning

confidence: 99%

“…Otherwise, a droplet breakup would cause a loss of mass and violate the mass balance. Since the daughter drop size distribution of the Coulaloglou and Tavlarides (1977) model is implemented as a normal distribution, it does not fulfil the mentioned requirements. Thus, a relatively narrow normal distribution was applied for the binary droplet breakup (number of daughter droplets nd = 2) of a droplet with volume : a mean daughter drop volume = and a standard deviation of = 5 was used.…”

Section: Numerical Investigations and Parameter Estimationmentioning

confidence: 99%

“…At the beginning, all parameters of the basic Coulaloglou and Tavlarides (1977) model were optimized to the transient development of the Sauter mean diameter d32 at pH 7. To provide comparability between the models, these fitted parameters for drop breakage (c1,b and c2,b) and collision frequency (c1,c) were kept constant throughout the whole study.…”

Section: Numerical Investigations and Parameter Estimationmentioning

confidence: 99%

“…For the coalescence efficiency sub model(s) the corresponding 'hydrodynamic' parameter c2,c was also adapted to pH 7 and the 'electrostatic' parameter c3,c was adjusted to transient data of d32 at pH 13. All parameters are given in SI units if dimensional: c2,c of the Coulaloglou and Tavlarides (1977) Kamp et al (2012). All simulations were verified to be independent from the initial drop size distribution after a few seconds or iteration steps, respectively.…”

Section: Numerical Investigations and Parameter Estimationmentioning

confidence: 99%

See 2 more Smart Citations

Coalescence efficiency model including electrostatic interactions in liquid/liquid dispersions

Kamp¹,

Kraume²

2015

Chemical Engineering Science

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The drop size distribution is an essential process variable in liquid/liquid systems and relevant in many technical applications. It can be described by population balance equations. A coalescence efficiency model was developed to be able to describe the well-known coalescence inhibition due to changing pH value or salt concentration. The model includes the attractive van der Waals and repulsive electrostatic force according to the DLVO theory into the population balance equation framework. This DLVO model can extend existing simulations in a straightforward manner due to a conceptual implementation. Moreover, zeta potential measurements were performed and the model was applied to simulate experiments in a stirred tank. Hence, the drop size distribution could be predicted well with changing pH value. The results are discussed in comparison to simulations with existing models in literature.

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Modeling of the Suspension Polymerization Process Using a Particle Population Balance

Chen

Pauer

Moritz

et al. 1999

Chem. Eng. Technol.

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On the basis of a population balance and the kinetic mechanism of free-radical suspension polymerization, a mathematical model of the suspension polymerization process is proposed. The population balance model which describes a mechanism involving the particle size distribution (PSD) in disperse systems leads to an integrodifferential equation. The basic numerical approach of this work is to use the finite-difference-differential technique with the logarithmic scale for particle size. The problem then was reduced to obtaining the numerical solution of a set of nonlinear ordinary differential equations. The numerical solutions were compared to experimental data, such as the reaction conversion which includes the gel effect and the particle size distributions, to yield the model parameters by Marquardt's method. The regression demonstrates reasonably good accuracy.

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Description of interaction processes in agitated liquid-liquid dispersions

Cited by 1,097 publications

References 34 publications

Stability of drug-carrier emulsions containing phosphatidylcholine mixtures

Stability of drug-carrier emulsions containing phosphatidylcholine mixtures

Coalescence efficiency model including electrostatic interactions in liquid/liquid dispersions

Modeling of the Suspension Polymerization Process Using a Particle Population Balance

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