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Identifier

000442170

Title

Formulation and characterization of liposomes and nanoemulsions for targeted drug delivery

Alternative Title

Ανάπτυξη και χαρακτηρισμός λιποσωμάτων και νανογαλακτωμάτων για στοχευμένη παροχή φαρμάκων

Author

Παπαβασιλείου, Μαλαματένια Γ.

Thesis advisor

Γανωτάκης, Δημήτριος

Reviewer

Χανιωτάκης, Νικόλαος
Τσιώτης, Γεώργιος

Abstract

Targeted drug delivery employs carriers to transfer therapeutics mainly to tissues of interest and to tackle issues such as drug solubility, and short circulation time. This thesis focuses on two drug delivery systems: liposomes and nanoemulsions. Liposomes are self-assembly structures of phospholipids, with an aqueous core, which makes them ideal in hydrophilic drug encapsulation or hydrophobic drug incorporation in their lipid bilayer. The aim of this study was to investigate the optimal composition of the liposomal formulations prepared by thin-film hydration. Conventional, stealth, and stimuli-responsive liposomes were characterized with dynamic light scattering, electrophoretic light scattering, and microscopy, while fluorescent dye-loaded liposomes were examined with microscopy and UV-vis spectroscopy. Parameters that could affect either the formulation or the characterization process were also evaluated. Depending on the formulation’s ingredients, liposomal sizes ranged from 150 to 300 nm. The liposomes also exhibited low polydispersity and good stability during storage. Nanoemulsions are also a promising alternative; they consist of an oily core and a surfactant monolayer. Two types of non-ionic surfactants were examined, a mixture of Span80/Tween20 as well as Kolliphor HS 15. The phase inversion temperature method was used for the nanoemulsion preparation. Dynamic light scattering, electrophoretic light scattering, and microscopy were employed for the characterization of the nanoemulsion droplets size, zeta-potential, polydispersity, and morphology. The choice of the surfactant affected immensely the characteristics of the nanoemulsion. The average diameter of the nanoemulsions ranged from 40 nm to 120 nm. Apart from empty nanoemulsions, a reverse micelle-loaded nanoemulsion was also prepared. This work includes an extensive literature review, an attempt to answer the questions that arose during the experiments, and an evaluation of the limitations of the presented methodologies.

Language

English

Subject

Drug delivery systems

Dynamic light scattering

Fluorescence microscopy

Phase inversion temperature

Thin-film hydration

Δυναμική σκέδαση φωτός

Ενυδάτωση λεπτής μεμβράνης

Θερμοκρασία αναστροφής φάσης

Μικροσκοπία φθορισμού