uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Catanionic drug-surfactant mixtures: Phase behavior and sustained release from gels
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 Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
2003 (English)In: Pharmaceutical research, ISSN 0724-8741, E-ISSN 1573-904X, Vol. 20, no 10, 1661-1667 p.Article in journal (Refereed) Published
Abstract [en]

PURPOSE: To study mixtures of SDS and the drugs diphenhydramine, tetracaine, and amitriptyline to compile phase diagrams and to investigate the use of interesting phases for sustained release from gels. METHODS: Phase diagrams were composed by studying large numbers of different compositions of negatively charged SDS and positively charged drug compounds visually, rheologically, and by cryotransmission electron microscopy. Drug release from Carbopol 940 and agar gels containing interesting phases, e.g., vesicle and branched micelle phases, was measured in vitro by the USP paddle method. RESULTS: Vesicles and elongated and branched micelles were formed on the SDS-rich side in all three systems examined. The tetracaine system differed from the other two in that it showed a vesicle area in the drug-rich side. Release of diphenhydramine from Carbopol 940 gels was slowed by at least a factor of 10 when in the form of vesicles or branched micelles. The same delay was found for both drug-rich and SDS-rich tetracaine vesicles. CONCLUSIONS: Mixtures of SDS and positively charged drugs form the same interesting phases as traditional catanionic mixtures. This may prove useful in obtaining functional controlled-release systems when using gels as drug carriers.

Place, publisher, year, edition, pages
2003. Vol. 20, no 10, 1661-1667 p.
Keyword [en]
catanionic mixtures, surfactant, gel, slow-release, phase diagram
National Category
Pharmaceutical Sciences
URN: urn:nbn:se:uu:diva-96412DOI: 10.1023/A:1026103805283ISI: 000185977600022PubMedID: 14620523OAI: oai:DiVA.org:uu-96412DiVA: diva2:170979
Available from: 2007-11-16 Created: 2007-11-16 Last updated: 2014-12-30Bibliographically approved
In thesis
1. Prolonged Drug Release from Gels, using Catanionic Mixtures
Open this publication in new window or tab >>Prolonged Drug Release from Gels, using Catanionic Mixtures
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The use of catanionic drug-surfactant mixtures was proven to be an efficient novel method of obtaining prolonged drug release from gels. It was shown that various commonly used drug compounds are able to form catanionic mixtures together with oppositely charged surfactants. These mixtures exhibited interesting phase behaviour, where, among other structures, vesicles and large worm-like or branched micelles were found. The size of these aggregates makes them a potential means of prolonging the drug release from gels, as only monomer drugs in equilibrium with larger aggregates were readily able to diffuse through the gel. When the diffusion coefficient for drug release from the formulation based upon a catanionic mixture was compared to that obtained for the drug substance and gel alone, the coefficient was some 10 to 100 times smaller.

The effects of changes in the pH and ionic strength on the catanionic aggregates was also investigated, and this method of prolonging the release was found to be quite resilient to variations in both. Although the phase behaviour was somewhat affected, large micelles and vesicles were still readily found. The drug release was significantly prolonged even under physiological conditions, that is, at a pH of 7.4 and an osmolality corresponding to 0.9% NaCl.

Surfactants of low irritancy, capric and lauric acid, may successfully be used instead of the more traditional surfactants, such as sodium lauryl sulfate (SDS), and prolonged release can still be obtained with ease.

Some attempts to deduce the release mechanism from the proposed systems have also been made using transient current measurements, dielectric spectroscopy, and modelling of the release using the regular solution theory. In these studies, the previous assumptions made concerning the mechanism responsible for the release were confirmed to a large extent. Only small amounts of the drug existed in monomer form, and most seemed to form large catanionic aggregates with the oppositely charged surfactant.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2007. 66 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, ISSN 1651-6192 ; 65
Pharmaceutics, gel, catanionic, vesicle, micelle, controlled release, diffusion, surfactant, drug delivery, Galenisk farmaci
urn:nbn:se:uu:diva-8303 (URN)978-91-554-7017-3 (ISBN)
Public defence
2007-12-07, B42, BMC, Husargatan 3, Uppsala, 09:15
Available from: 2007-11-16 Created: 2007-11-16Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Paulsson, MattiasEdwards, Katarina
By organisation
Department of PharmacyPhysical Chemistry
In the same journal
Pharmaceutical research
Pharmaceutical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 497 hits
ReferencesLink to record
Permanent link

Direct link