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A miniaturized in vitro release method for investigating drug-release mechanisms
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.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
2015 (English)In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 486, no 1-2, p. 339-349Article in journal (Refereed) Published
Abstract [en]

We have evaluated a miniaturized in vitro method, based on the mDISS Profiler (TM) technique that enables on-line monitoring of drug release from a 21 mu l sample with 10 ml of release medium. Four model drugs in eight clinically used formulations, including both solid and non-solid drug delivery systems, were investigated. The acquired data were compared with historical in vitro release data from the same formulations. Use of the Weibull function to describe the in vitro drug-release profiles allowed discrimination between the selected formulations with respect to the drug-release mechanisms. Comparison of the release data from the same formulation in different in vitro set-ups showed that the methodology used can affect the mechanism of in vitro release. We also evaluated the ability of the in vitro methods to predict in vivo activity by comparing simulated plasma concentration-time profiles acquired from the application of the biopharmaceutical software GI-Sim to the in vitro observations. In summary, the simulations based on the miniaturized-method release data predicted the plasma profiles as well as or more accurately than simulations based on the historical release data in 71% of the cases and this miniaturized in vitro method appears to be applicable for both solid and non-solid formulations.

Place, publisher, year, edition, pages
2015. Vol. 486, no 1-2, p. 339-349
Keywords [en]
In vitro release methods, Release mechanisms, Weibull function, GI-Sim, In vivo prediction
National Category
Pharmaceutical Sciences
Identifiers
URN: urn:nbn:se:uu:diva-255064DOI: 10.1016/j.ijpharm.2015.03.076ISI: 000353999100037PubMedID: 25843760OAI: oai:DiVA.org:uu-255064DiVA, id: diva2:824743
Available from: 2015-06-22 Created: 2015-06-12 Last updated: 2018-10-30Bibliographically approved
In thesis
1. In vitro evaluation of formulations used in the treatment of hepatocellular carcinoma
Open this publication in new window or tab >>In vitro evaluation of formulations used in the treatment of hepatocellular carcinoma
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Hepatocellular carcinoma (HCC) causes ~ 600,000 deaths annually, making it the second most deadly cancer form. HCC is classified into five stages and for the intermediate HCC treatment, the two most commonly used drug delivery systems (DDSs) are lipiodol-based emulsions and drug-eluting beads. The aims of this thesis were to develop in vitro methods suitable for studying these DDSs. It is important to investigate the release mechanisms and release rates with relevant in vitro methods, as this can improve the understanding of the in vivo performance. Miniaturized in vitro methods with sample reservoirs separated from the release medium by a diffusion barrier were developed and shown to be suitable for studying drug release from particle DDSs (Paper I). In Paper II these methods were further developed and used to study the release of doxorubicin (DOX) from the clinically used drug-eluting beads. DOX release rates were affected by the method set-up and the characteristics of the release medium. The choice of method and volume of release medium could improve the in vivo-likeness of the in vitro release profiles. Applied theoretical models suggested a film-controlled type of DOX release mechanism from the beads when self-aggregation, DOX-bead interaction, and DOX deprotonation were taken into account.

A micropipette-assisted microscopy method was used to further improve the understanding of the release mechanism of amphiphilic molecules from the beads (Paper III). A detailed analysis suggested an internal depletion-layer model dependent on molecular self-aggregation for the release. It was further suggested that a simple ion-exchange mechanism is unrealistic in physiological conditions.

The important pharmaceutical factors for the emulsion-based formulations were investigated in Paper IV. DOX solubility, lipid phase distribution, and emulsion stability increased when the contrast agent iohexol was added. Also, an increase in release half-life (h) was observed from emulsions with iohexol.

The in vitro methods and theoretical models presented in this thesis can be used during development and optimization of future DDSs.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2018. p. 61
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, ISSN 1651-6192 ; 261
Keywords
Drug delivery system, Doxorubicin, Microgel, Emulsion, Hepatocellular carcinoma
National Category
Pharmaceutical Sciences
Research subject
Biopharmaceutics
Identifiers
urn:nbn:se:uu:diva-361017 (URN)978-91-513-0498-4 (ISBN)
Public defence
2018-12-20, A1:111a, BMC, Husargatan 3, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2018-11-27 Created: 2018-10-30 Last updated: 2018-12-27

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Ahnfelt, EmelieSjögren, ErikLennernäs, Hans

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