Katı Lipit Nanopartiküller Kullanılarak Kolloidal Mikrokapsül Üretimi

Abstract

Nanoparticles have been driving much attention in the last years since they can be

used both in scientific studies and in medical and technological applications,

Nanoparticles can be synthesized by utilizing a variety of constituents, among

which the most studied ones are metallic, polymeric and lipid based nanoparticles.

The size, shape, and the surface functionalities of nanoparticles as well as the

material which is synthesized vary in accordance with and relative to their target

applications. Solid lipid nanoparticles (SLNs), which are synthesized by using

various physiological lipids, emulsifiers and water, have first come into use as an

alternative nanocarrier in 1990s. Due to their high biocompatibility, stability and

availability/efficiency to encapsulate various active materials, SLNs are positively

distinguished from other alternatives in many fields, pharmaceutical and

biomedical applications in particular. In addition, since they possess biocompatible

and physiologically related raw materials and adjustable release kinetics which

depend on the synthesis method, SLNs are an ideal alternative to be used in the

body for different purposes and with various administration routes. In the first

stage of the study, it has been aimed to prepare and characterize SLNs with

proper size and surface functionalities to calculate their drug

encapsulation/release capacities. In order to characterize the SLNs which are

prepared by using “Microemulsion Method”, Atomic Force Microscopy (AFM) and

v

Dynamic Light Scattering (DLS) have been utilized to get information regarding

size, the polydispersity, and geometry, while zeta potential measurements have

brought out surface charge density of the SLNs prepared. Moreover, thermal

properties and morphological structures of SLNs have been studied in detail with

Differential Scanning Calorimetry (DSC) technique. The size and zeta potential

values of SLNs have been re-measured three months after the synthesis in order

to evaluate high long-term stability feature, which is cited as one of the major

advantages of SLNs in literature. Ascorbic acid (AA) and methylene blue (MB)

have been used as model drugs to evaluate the drug encapsulation/release

capacities of SLNs prepared with certain specifications. MB has been attached to

the surface of the SLNs with electrostatic interaction whereas AA has been loaded

in the particle structure during the synthesis. Drug encapsulation/release

capacities have been analyzed by UV-vis spectrophotometry. In the second part of

the study SLNs have been used as building block to prepare colloidal

microcapsules. It is very common to use metallic nanoparticles to prepare

microcapsule structure. The synthesis of MCs whose shell-side is constructed by

SLNs, is the first in literature. While polystyrene particles and Ibuprofen drug

crystals have been used as the core material, SLNs, gold nanoparticles and

chitosan have been used in the shell-side. The shell of the MCs has been

prepared with “Layer-by-layer method” with use of electrostatic interaction of

materials. The coating performance of each layer has been monitored by

measuring zeta potential changes after each layer of coating. In addition, the

layers have been viewed with Scanning Electron Microscope (SEM). In addition,

encapsulation/release performance of MCs was investigated by using these

predetermined model molecules. As a result, the introduced MCs by this thesis

which has produced by using SLNs as building blocks has been achieved for the

first time in literature and a good alternative for both multiple drug delivery and as

a diagnostic tool which will launce lots of new project for more functional drug

delivery vehicles. What is more, with gold nanoparticles added to the MC

structure, new- generation colloidal structures have been produced which can be

used in both diagnosis and treatment.