Polydispersity index and molecular weight distributions of polymers

Rogošić, Marko; Mencer, Helena Jasna; Gomzi, Zoran

doi:10.1016/s0014-3057(96)00091-2

Cited by 118 publications

(68 citation statements)

References 17 publications

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“…Thus, the DTX loading was found to only marginally increase the mean particle size of the cubosomes. Moreover, the low polydispersity index values, 0.162±0.014 and 0.173±0.019 for blank cubosomes (CD1) and DTX-loaded cubosomes (CD2), respectively, indicated a narrow particle size distribution (47). Zeta potential is another important index for the stability of the cubosomes.…”

Section: Particle Size Determinationmentioning

confidence: 98%

Nanostructured Cubosomes in a Thermoresponsive Depot System: An Alternative Approach for the Controlled Delivery of Docetaxel

et al. 2015

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Abstract. The aim of the present study was to develop and evaluate a thermoresponsive depot system comprising of docetaxel-loaded cubosomes. The cubosomes were dispersed within a thermoreversible gelling system for controlled drug delivery. The cubosome dispersion was prepared by dilution method, followed by homogenization using glyceryl monooleate, ethanol and Pluronic ® F127 in distilled water. The cubosome dispersion was then incorporated into a gelling system prepared with Pluronic ® F127 and Pluronic ® F68 in various ratios to formulate a thermoresponsive depot system. The thermoresponsive depot formulations undergo a thermoreversible gelation process i.e., they exists as free flowing liquids at room temperature, and transforms into gels at higher temperatures e.g., body temperature, to form a stable depot in aqueous environment. The mean particle size of the cubosomes in the dispersion prepared with Pluronic ® F127, with and without the drug was found to be 170 and 280 nm, respectively. The prepared thermoresponsive depot system was evaluated by assessing various parameters like time for gelation, injectability, gel erosion, and in-vitro drug release. The drug-release studies of the cubosome dispersion before incorporation into the gelling system revealed that a majority (∼97%) of the drug was released within 12 h. This formulation also showed a short lag time (∼3 min). However, when incorporated into a thermoresponsive depot system, the formulation exhibited an initial burst release of ∼21%, and released only ∼39% drug over a period of 12 h, thus indicating its potential as a controlled drug delivery system.

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Section: Particle Size Determinationmentioning

confidence: 98%

Nanostructured Cubosomes in a Thermoresponsive Depot System: An Alternative Approach for the Controlled Delivery of Docetaxel

et al. 2015

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“…The pump flow rate is 1.0 mL/min with THF as the carrier solvent, and injection volumes are set to 20 lL. The polydispersity index [21] which indicates the nature of the distribution of the molecular weights in the polymers was also calculated.…”

Section: Determination Of the Molecular Weightmentioning

confidence: 99%

Dodecyl methacrylate and vinyl acetate copolymers as viscosity modifier and pour point depressant for lubricating oil

et al. 2017

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The article presents application of homo polymer of dodecyl methacrylate (DDMA) and its copolymers with vinyl acetate (VA) as multifunctional additives for lubricant formulation. Homo polymer of DDMA and five copolymers of DDMA with VA at different molar ratios were synthesized by free radical polymerization method using azobisisobutyronitrile (AIBN) as initiator. The characterization of the polymers was carried out through FTIR, NMR and GPC (gel permeable chromatography) analysis. The performance of all the polymers as viscosity index improver (VII) or viscosity modifier and pour point depressant (PPD) additive in two different base oils (mineral) were evaluated. The mechanism of action of the polymers as pour point depressant was studied by photo micrographic analysis. Rheological study of the formulated lubricant was also carried out and reported. The thermal stability of the polymers was determined by thermogravimetric analysis (TGA). It was found that thermal stability, VI and molecular weights of copolymers are higher than the homopolymer which showed better PPD property.

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“…In colloid literature, the polydispersity of some property is σ, the standard deviation of the distribution in units of its mean. Polydispersity of polymers 4,5 (usually quantified by a 'polydispersity index' which is unity in the monodisperse case) is ubiquitous and can be significantly larger than typical values in colloids. Polydispersity is also present -intentionally -in virtually all studies of colloidal glasses 6 , but relatively little attention has so far been paid to its role beyond the pragmatic necessity of preventing crystallisation (one recent exception being Ref.…”

Section: Introductionmentioning

confidence: 99%

Measuring local volume fraction, long-wavelength correlations, and fractionation in a phase-separating polydisperse fluid

Williamson

Evans

2014

The Journal of Chemical Physics

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We dynamically simulate fractionation (partitioning of particle species) during spinodal gas-liquid separation of a size-polydisperse colloid, using polydispersity up to ∼ 40% and a skewed parent size distribution. We introduce a novel coarse-grained Voronoi method to minimise size bias in measuring local volume fraction, along with a variety of spatial correlation functions which detect fractionation without requiring a clear distinction between the phases. These can be applied whether or not a system is phase separated, to determine structural correlations in particle size, and generalise easily to other kinds of polydispersity (charge, shape, etc.). We measure fractionation in both mean size and polydispersity between the phases, its direction differing between model interaction potentials which are identical in the monodisperse case. These qualitative features are predicted by a perturbative theory requiring only a monodisperse reference as input. The results show that intricate fractionation takes place almost from the start of phase separation, so can play a role even in nonequilibrium arrested states. The methods for characterisation of inhomogeneous polydisperse systems could in principle be applied to experiment as well as modelling.

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Polydispersity index and molecular weight distributions of polymers

Cited by 118 publications

References 17 publications

Nanostructured Cubosomes in a Thermoresponsive Depot System: An Alternative Approach for the Controlled Delivery of Docetaxel

Nanostructured Cubosomes in a Thermoresponsive Depot System: An Alternative Approach for the Controlled Delivery of Docetaxel

Dodecyl methacrylate and vinyl acetate copolymers as viscosity modifier and pour point depressant for lubricating oil

Measuring local volume fraction, long-wavelength correlations, and fractionation in a phase-separating polydisperse fluid

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