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The Release of Catanionic Mixtures Embedded in Gels: An Approximate Analytical Analysis
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.ORCID iD: 0000-0002-0895-1180
2011 (English)In: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, Vol. 57, no 6, 1402-1408 p.Article in journal (Refereed) Published
Abstract [en]

We present an approximate analytical analysis of the release of catanionic mixtures from gels. The starting points are the monomer-mixed micelle equilibrium, described by using regular solution theory, and the one-dimensional diffusion equation. Focusing on a half-infinite planar system, we first point out an exact reduction of the problem to a system of ordinary differential equations. By using the pseudo-steady-state approximation and the integral-balance method, we then derive a single nonlinear equation for the mole fraction of drug in micelles at the extraction front. This equation may be readily solved numerically (or graphically), and once the solution is found, all quantities of interest may be determined in closed form. Comparisons with numerical solutions of the fully nonlinear problem indicate that the errors resulting from the approximations typically do not exceed 10%.

Place, publisher, year, edition, pages
2011. Vol. 57, no 6, 1402-1408 p.
Keyword [en]
controlled drug delivery, release, drug release, mathematical modeling, diffusion, catanionic mixtures
National Category
Pharmaceutical Sciences
Identifiers
URN: urn:nbn:se:uu:diva-154684DOI: 10.1002/aic.12368ISI: 000290616500004OAI: oai:DiVA.org:uu-154684DiVA: diva2:421631
Available from: 2011-06-09 Created: 2011-06-09 Last updated: 2016-04-27Bibliographically approved
In thesis
1. Molecular Arrangement, Electronic Structure and Transport Properties in Surfactant Gel- and Related Systems Studied by Soft X-ray and Dielectric Spectroscopy
Open this publication in new window or tab >>Molecular Arrangement, Electronic Structure and Transport Properties in Surfactant Gel- and Related Systems Studied by Soft X-ray and Dielectric Spectroscopy
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis concerns studies of aqueous soft matter systems, especially surfactant micelle systems.

The aim has been to study the molecular arrangement and electronic structure of the constituents of, as well as transport properties in such a system. The molecular arrangement and electronic structure has been studied by means of X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray spectroscopy (RIXS). The transport properties have been investigated by low-frequency dielectric spectroscopy (LFDS) and small angle X-ray scattering (SAXS) as well as a theoretical modelling. The latter was based on Fick’s laws of the release from binary surfactant system and was validated by experiments.

The RIXS and XAS measurements show the electronic structure in bulk water and the influence of the chemical surrounding of the water molecule in bulk water and of the water molecules confined in a micelle lattice. The spectra are highly dependent on the molecular arrangement in such systems. For glycine and sodium polyacrylate RIXS and XAS spectra show features which are unique for carboxyl and carboxylate groups and such measurements can thus be used for fingerprinting.

The LFDS and SAXS measurements show a strong correlation between structure in a surfactant/poly-ion system and apparent mobility of surfactants. This conclusion is in line with earlier observations.

By the theoretical modelling a predictive model for the surfactant release from a binary surfactant micelle system has been obtained and the importance of different factors for surfactant release has been further clarified.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. 77 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1060
Keyword
surfactants, surfactant/poly-ion gel, water, confined water, XAS, RIXS, dielectric spectroscopy, SAXS, pKa, transport, Fick’s law
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-205072 (URN)978-91-554-8721-8 (ISBN)
Public defence
2013-09-27, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:30 (Swedish)
Opponent
Supervisors
Available from: 2013-09-04 Created: 2013-08-13 Last updated: 2014-01-08

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Frenning, GöranGråsjö, JohanHansson, Per
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