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A characterisation study on the application of inverted lyotropic phases for subcutaneous drug release
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Pharmacology.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
2010 (English)In: International journal of pharmaceutics, ISSN 1873-3476, Vol. 388, no 1-2, 52-7 p.Article in journal (Refereed) Published
Abstract [en]

An experimental characterisation of lipid mixtures consisting of inverted hexagonal and inverted cubic phases composed of soybean phosphatidylcholine (SPC) and glycerol dioleate (GDO) was performed. The release of five chromophores of varying lipophilicity, used as model drugs, was investigated. Two experimental setups were applied: one based on maintaining sink condition, while a constant volume release medium was employed for the other. For neither setup, no correlation between the model drug lipophilicity and the polarity of the carrier matrix was found. However, the lipid phases showed a prolonged release, spanning weeks, of the model drugs, which exhibit lipophilicity values ranging by four orders of magnitude.

Place, publisher, year, edition, pages
Elsevier B.V. , 2010. Vol. 388, no 1-2, 52-7 p.
Keyword [en]
Subcutaneous drug delivery, Drug depot, Lipid formulations, Lipophilicity, Model drugs
URN: urn:nbn:se:umu:diva-30752DOI: 10.1016/j.ijpharm.2009.12.032ISI: 000275526100006PubMedID: 20026201OAI: diva2:286527
Available from: 2010-01-14 Created: 2010-01-14 Last updated: 2011-04-08Bibliographically approved
In thesis
1. Optical characterization of potential drugs and drug delivery systems
Open this publication in new window or tab >>Optical characterization of potential drugs and drug delivery systems
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This Thesis is a characterization study on substances having potency as drugs as well as on a lipid based drug-delivery matrix. The optical properties of newly synthesized molecules with proven pilicide properties have been characterized with several spectroscopic methods. These methods include optical absorption and fluorescence as well as time-resolved fluorescence. Upon covalently linking compounds with high quantum yields of fluorescence to specific parts of the pilicide, the biological impact was found to increase for some of the derivatives. Furthermore, by expanding the aromatic part of the pilicide molecule, a significant increase in the inherent fluorescence was obtained. The S0-S1 absorption band for these molecules was found to originate from an impure electronic transition, vibronically promoted by intensity borrowing from higher electronic states.

Included in this Thesis is the measurement of how deeply some in this class of newly synthesized molecules become situated when placed inside ganglioside GM1 micelles, and how the molecules’ reorientation is affected. By means of radiation-less energy transfer, it was shown that the molecules place themselves close to the hydrophobic-hydrophilic interface inside the GM1 micelles. As a consequence they are exposed to a densely packed environment, which inhibits the free tumbling of the molecule. This restricted tumbling could be measured by means of time-resolved depolarization experiments.

The release of drug-like fluorescent molecules is investigated from a lipid mixture, which upon equilibrium with water forms a mixture of inverted hexagonal and cubic phases. The lipid matrix displayed an extended release over the course of weeks, in vitro, for molecules having a large variation in hydrophobicity.

Place, publisher, year, edition, pages
Umeå: Kemiska institutionen, Umeå universitet, 2011. 35 p.
Pilicide, Ganglioside GM1 micelles, Drug Delivery, Elecronic Energy Transfer, UV-Vis Absorption, Fluorescence Spectroscopy
National Category
Physical Chemistry
Research subject
Physical Chemistry
urn:nbn:se:umu:diva-40177 (URN)978-91-7459-157-6 (ISBN)
Public defence
2011-03-11, KBC-huset, KB3A9, Umeå Universitet, Umeå, 10:00 (English)
Available from: 2011-02-18 Created: 2011-02-16 Last updated: 2011-02-18Bibliographically approved

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