Infrared and microcalorimetric studies of the adsorption of monofunctional ketones, esters, ethers, and alcohols at the silica/carbon tetrachloride interface

Korn, Milan; Killmann, E.; Eisenlauer, J.

doi:10.1016/0021-9797(80)90266-0

Cited by 46 publications

(24 citation statements)

References 20 publications

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“…4) demonstrated, for the first time, that colloidal silica permeated in vivo in the upper region of the human stratum corneum and hence could promote the transport of adsorbed quercetin. This hypothesis is corroborated by the strong adsorptive properties of silica towards a wide range of active agents [31,52,53]. Adsorption of quercetin on the silica surface may also modify the vehicle/stratum corneum partition coefficient of the flavonoid and hence its uptake by the skin [33,34].…”

Section: Discussionmentioning

confidence: 63%

Comparative Evaluation of the Effect of Permeation Enhancers, Lipid Nanoparticles and Colloidal Silica on in vivo Human Skin Penetration of Quercetin

Scalia

Franceschinis

Bertelli

et al. 2012

Skin Pharmacol Physiol

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Background/Aim: The aim of this study was to evaluate emulsions containing a penetration enhancer, lipid nanoparticles (LNs) or colloidal silica as systems to improve the topical delivery of the flavonoid quercetin. Methods: The skin penetration of quercetin was investigated in vivo on human volunteers by tape stripping. Quercetin-loaded LNs were prepared using hot high-pressure homogenization and characterized by means of dynamic light scattering and release studies. The location of the silica nanoparticles in the skin was determined by inductively coupled plasma mass spectrometry assay of silicon in the stratum corneum strips. Results and Conclusions: The penetration enhancer diethylene glycol monoethyl ether did not produce any significant increase in the fraction of the applied quercetin dose permeated in vivo into human stratum corneum (17.1 ± 3.2%) compared to the control emulsion (18.1 ± 2.3%). A greater but statistically nonsignificant accumulation of the flavonoid in the human horny layer (21.2 ± 2.9% of the applied dose) was measured following topical application of quercetin-loaded LNs (mean particle size: 527 nm). On the other hand, the addition of colloidal silica (average particle diameter: 486 nm) to the emulsion (2%, w/w) significantly increased the in vivo uptake of quercetin by the human stratum corneum to 26.7 ± 4.1% of the applied dose, the enhancing effect on permeation being more marked in the deepest horny layer strips. The measured in vivo skin penetration profile of colloidal silica showed that silica particles diffused down to the intermediate region of the human horny layer and hence could act as carrier for quercetin.

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Section: Discussionmentioning

confidence: 63%

Comparative Evaluation of the Effect of Permeation Enhancers, Lipid Nanoparticles and Colloidal Silica on in vivo Human Skin Penetration of Quercetin

Scalia

Franceschinis

Bertelli

et al. 2012

Skin Pharmacol Physiol

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“…Cuvettes of variable path length with NaC1 windows (VCO 1, Beckman) were applied. Details of the experimental procedure have been reported in [7,17].…”

Section: Methodsmentioning

confidence: 99%

Fraction of H-bonded segments of N-ethylpyrrolidone, oligomeric and polymeric vinylpyrrolidone adsorbed from CHCl3 on silica measured by IR spectrometry

Killmann¹,

Bergmann²

1985

Colloid & Polymer Sci

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Abstract:The adsorption of N-ethylpyrrolidone (NEP), oligomeric and polymeric vinylpyrrolidone (OVP, PVP) on silica (Aerosi1200) from CHC13 solution is investigated by IR spectrometry. The influence of the annealing temperature of the silica on the adsorbed amount and on the fraction of adhered segments was studied. The dependences of the amount adsorbed on solution concentration result for NEP in a Langmuir isotherm for OVP and PVP in high affinity isotherms. The fraction of adhered H-bridged carbonyl groups determined by compensation procedures, the fraction of surface SiOH groups occupied and the mukiple interaction quotient Q show different dependences on the amount adsorbed for the measured adsorptives, indicating different interactions of the monomeric segments with the surface groups. This behaviour is explained by comparing the amount adsorbed in saturation with monolayer capacities, surface concentration of SiOH groups and frequency shifts. A splitting of the band of the bound carbonyl groups in a double peak was observed with OVP and PVP, referring to an additional interaction of polymer segments neighboured to specifically bound segments.

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“…(1) from the measured heat z~Hmeas produced by the addition of polymer solution to the standard pretreated silica suspension in CCI 4 [4,6]. The dilution heat AH a in the corresponding experiment without silica has to be considered.…”

Section: Homopolymersmentioning

confidence: 99%

“…Formula (3) is derived in previous publications [2,4,5]. Assuming that one adsorbing polymer segment displaces one CC14-molecule from the surface with measured piR-Values, the AHp, A values are calculated at full coverage in Table 1 and at low coverage in Table 2.…”

Section: (1)mentioning

confidence: 99%

“…At low coverage the macromolecules are able to adsorb undisturbed under displacement of solvent molecules with the highest possible number of segments. The obtained fractions p > 0.5 at very low coverage have to be explained by multiple interactions [4,6,10] between more than one SiOH-group and one polymer segment. With increasing coverage the macromolecules are not allowed to be adsorbed with the highest number of segments because a competition exists for the available surface sites with segments of other macromolecules.…”

Section: Fraction Of Adhered Segmentsmentioning

confidence: 99%

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Microcalorimetric adsorption enthalpies of ethylene oxide and propylene oxide copolymers from CCl4 and H2O on pyrogenic silica

Killmann

Melchior

Interfaces in Condensed Systems

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The adsorption enthalpies of block-and statistic copolymers of ethylene oxide (EO) and propylene oxide (PO), and of corresponding homopolymers on silica (Aerosil 200) from CC14 and H20 are determined by microcalorimetry. With adsorption isotherms measured separately from the concentration difference in the solution fraction of adhered segments, Peal, the binding enthalpies have been deduced. The pcaFvalues from CCl 4 decrease with increasing amount adsorbed, molar mass, EO-fraction and -blocklength. The hydroxyl endgroups of the polymers strongly influence the adsorption enthalpies. With results on preferential adsorption of the EOsegments the dependences are interpreted by conformation models.

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Infrared and microcalorimetric studies of the adsorption of monofunctional ketones, esters, ethers, and alcohols at the silica/carbon tetrachloride interface

Cited by 46 publications

References 20 publications

Comparative Evaluation of the Effect of Permeation Enhancers, Lipid Nanoparticles and Colloidal Silica on in vivo Human Skin Penetration of Quercetin

Comparative Evaluation of the Effect of Permeation Enhancers, Lipid Nanoparticles and Colloidal Silica on in vivo Human Skin Penetration of Quercetin

Fraction of H-bonded segments of N-ethylpyrrolidone, oligomeric and polymeric vinylpyrrolidone adsorbed from CHCl3 on silica measured by IR spectrometry

Microcalorimetric adsorption enthalpies of ethylene oxide and propylene oxide copolymers from CCl4 and H2O on pyrogenic silica

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