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Mechanically strong geopolymers offer new possibilities in treatment of chronic pain
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
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2010 (English)In: Journal of Controlled Release, ISSN 0168-3659, E-ISSN 1873-4995, Vol. 146, no 3, 370-377 p.Article in journal (Refereed) Published
Abstract [en]

We propose that a clay derived class of materials, known as geopolymers, may solve the problem of finding materials for controlled release with the right combination of properties necessary for a safe and sustained oral delivery of highly potent opioids. We show that the opioid Fentanyl, and its structurally similar sedative Zolpidem, can be embedded into metakaolin based geopolymer pellets to provide prolonged release dosage forms with mechanical strengths of the same order of magnitude as that of human teeth. The results presented in the current work may open up new opportunities for future development of drug delivery for high potency drugs employing high-strength and variable-pore-structure geopolymers and materials alike.

Place, publisher, year, edition, pages
2010. Vol. 146, no 3, 370-377 p.
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:uu:diva-131243DOI: 10.1016/j.jconrel.2010.05.029ISI: 000282398100014PubMedID: 20685295OAI: oai:DiVA.org:uu-131243DiVA: diva2:353705
Available from: 2010-09-28 Created: 2010-09-28 Last updated: 2017-12-12Bibliographically approved
In thesis
1. Functional Ceramics in Biomedical Applications: On the Use of Ceramics for Controlled Drug Release and Targeted Cell Stimulation
Open this publication in new window or tab >>Functional Ceramics in Biomedical Applications: On the Use of Ceramics for Controlled Drug Release and Targeted Cell Stimulation
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Ceramics are distinguished from metals and polymers by their inorganic nature and lack of metallic properties. They can be highly crystalline to amorphous, and their physical and chemical properties can vary widely. Ceramics can, for instance, be made to resemble the mineral phase in bone and are therefore an excellent substitute for damaged hard tissue. They can also be made porous, surface active, chemically inert, mechanically strong, optically transparent or biologically resorbable, and all these properties are of interest in the development of new materials intended for a wide variety of applications. In this thesis, the focus was on the development of different ceramics for use in the controlled release of drugs and ions. These concepts were developed to obtain improved therapeutic effects from orally administered opioid drugs, and to reduce the number of implant-related infections as well as to improve the stabilization of prosthetic implants in bone.

Geopolymers were used to produce mechanically strong and chemically inert formulations intended for oral administration of opioids. The carriers were developed to allow controlled release of the drugs over several hours, in order to improve the therapeutic effect of the substances in patients with severe chronic pain. The requirement for a stable carrier is a key feature for these drugs, as the rapid release of the entire dose, due to mechanical or chemical damage to the carrier, could have lethal effects on the patient because of the narrow therapeutic window of opioids. It was found that it was possible to profoundly retard drug release and to achieve almost linear release profiles from mesoporous geopolymers when the aluminum/silicon ratio of the precursor particles and the curing temperature were tuned.

Ceramic implant coatings were produced via a biomimetic mineralization process and used as carriers for various drugs or as an ion reservoir for local release at the site of the implant. The formation and characteristics of these coatings were examined before they were evaluated as potential drug carriers. It was demonstrated that these coatings were able to carry antibiotics, bisphosphonates and bone morphogenetic proteins to obtain a sustained local effect, as they were slowly released from the coatings.

 

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2010. 99 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 780
Keyword
Controlled release, geopolymer, sol-gel, opioid, oral administration, oral dosage form, implant, titanium, hydroxyapatite, infection, strontium carbonate, strontium
National Category
Other Materials Engineering Materials Engineering Other Engineering and Technologies not elsewhere specified
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-132377 (URN)978-91-554-7930-5 (ISBN)
Public defence
2010-12-10, Polhelmsalen, Ångströmslaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:00 (Swedish)
Opponent
Supervisors
Note

Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 710

Available from: 2010-11-18 Created: 2010-10-19 Last updated: 2014-01-21Bibliographically approved
2. Diffusion Controlled Drug Release from Slurry Formed, Porous, Organic and Clay-derived Pellets
Open this publication in new window or tab >>Diffusion Controlled Drug Release from Slurry Formed, Porous, Organic and Clay-derived Pellets
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Coronary artery disease and chronic pain are serious health issues that cause severe discomfort and suffering in society today. Antithrombotic agents and highly potent analgesics play a critical role in improving the recovery process for patients being treated for these diseases. This thesis focuses on the design and study of pellet-based drug dosage forms which allow diffusion-controlled delivery of drugs with the aim of achieving optimal therapeutic outcomes.

A wet slurry process was used to mix the drug and the polymer and/or clay precursor excipients into a paste. The pellets were then shaped via ionotropic gelation (alginate hydrogel beads/pellets), extrusion/spheronization (halloysite clay pellets) or geopolymerization.

The decrease in the drug diffusion rate in the alginate beads was affected by the drug's molecular size and charge and the characteristics (such as concentration and chemical structure) of the surrounding alginate gel.

The halloysite clay pellets provided sustained release of the highly potent drug fentanyl at both gastric pH 1 and intestinal pH 6.8. As expected, crushing the pellets reduced the diffusion barrier, resulting in more rapid release (dose dumping).

The use of mechanically strong geopolymer gels was investigated as a potential means of preventing dose dumping as a result of crushing of the dosage form. Variations in the synthesis composition resulted in drastic changes in the microstructure morphology, the porosity, the mechanical stability and the drug release rate. Pore network modeling and finite element simulations were employed to theoretically evaluate the effects of porosity and drug solubility in the geopolymer structure on the drug release process. Fitting the model parameters to experimental data showed that increased average pore connectivity, a greater pore size distribution, and increased drug solubility in the pellet resulted in an increased drug release rate. Furthermore, incorporation of pH-sensitive organic polymers in the geopolymer structure reduced the high drug release rate from the pellets at gastric pH. These results indicate that geopolymers have potential for use in pellet form; both the release rate of the drug and the mechanical stability of the pellets can be optimized to prevent dose dumping.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 80 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 884
Keyword
Diffusion, Drug delivery, Antithrombotic drugs, Highly potent opioids, Modeling, Clays, Polymers, Pellets, Beads
National Category
Pharmaceutical Sciences
Research subject
Materials Science
Identifiers
urn:nbn:se:uu:diva-161812 (URN)978-91-554-8229-9 (ISBN)
Public defence
2012-01-20, Häggsalen, Ångströmslaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:00 (English)
Opponent
Supervisors
Available from: 2011-12-21 Created: 2011-11-17 Last updated: 2013-07-22

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Jämstorp, ErikForsgren, JohanEngqvist, HåkanStrömme, Maria

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