Tabaka Tabaka Kaplama Metodu Kullanılarak Hazırlanan İlaç Yüklü Kontak Lenslerden Kontrollü İlaç Salımı
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Date
2018Author
Nihan, Ercioğlu
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CONTROLLED DRUG RELEASE FROM CONTACT LENSES
PREPARED BY USING THE LAYER-BY-LAYER METHOD
Nihan ERCİOĞLU
Master of Science, Department of Chemical Engineering
Supervisor: Prof. Dr. Nihal AYDOĞAN
May 2018, 120 pages
In this study it is aimed to use the drug loaded p-HEMA contact lenses
for the treatment of the conjunctivitis and glaucoma at the same time,
which are the most important eye diseases. A synthetic polymer p-HEMA
is used frequently for controlled release applications as well as being used
as a soft material. Dexametasone and Timolol were used as model drugs.
The surfaces of hydrogels were modified via ’’Layer by Layer’’ (LbL)
technique. This method is based on the electrostatic interaction between
complementary functional groups.
By using LBL method, we modified the surface of hydrogels with chitosan
and hyaluronic acid. Furthermore it is important that the studied material
must be biodegradable and biocompatible for using the biomedical
applications. Hydrogels were characterized by using FT-IR (Fourier
Transform Infrared Spectroscopy), DSC (Differential Scanning
Calorimetry) and SEM (Scanning Electron Microscope). The formation of
each layer was monitored by measuring the absorbance of methylene
v
blue, light transmittance and water contact angle of the lenses. Drug
release concentration was measured by using UV-vis spectroscopy.
Hydrogels prepared by LbL methods (2 double layer) have sustained drug
release in which only 50 % of drug was released in 25 hours. It was
demonstrated that the formed CH/HA layers act as a barrier for drug
release. Furthermore, addition of the drug-free chitosan layers on top of
this surface modified hydrogels (2 double layer) at different thickness
gave rise to further reduction at the drug release.
As a unique result, for the first time in literature, it is seen that addition
of drug free chitosan layers on the top of the surface modified hydrogels
had allowed us to observe a “delay time”. The observed delay time varied
with the changing thickness of the layer applied. Thickness of drug free
chitosan layer is 1,85 μm. The delay time increased from 5 minutes to 25
minutes with increasing thickness. Thus, controlled drug release was
accomplished.
Moreover, addition of chitosan layer on top of the contact lenses allowed
us to see a delay time before the release of drug as well as preventing
the burst release. Also, side effects of the drug were eliminated, which
was released at the beginning. The dose of drug, which each patient must
receive according to his/her drug regimen, can be adjusted by varying
the thickness or the changing the number of the layers applied without
losing the other functions of contact lenses such as correcting the vision.
A system treating multiple diseases at the same time has been provided.
The material which was never used before was developed for transport
of the ophthalmic drug release.
Keywords: Hydrogel, Chitosan, Layer by Layer, Drug Delivery,
Bioavailability, Contact Lenses