Insulin-inserted Hydroxyapatite as a Protein Drug Delivery Model for Diabetes Treatment
Date Issued
2012
Date
2012
Author(s)
Wei, Hung-Hsuan
Abstract
Protein and other macromolecular drugs have great potentials for the future development of medicine. However, most of these drugs are dosed by injection. It would become main trend if way of dosing macromolecular drugs can be more receptive to the patient. The purpose of this study is to develop a novel model of insulin-inserted hydroxyapatite (insHAP) and to prove whether crystal structure of hydroxtapatite could carry protein drugs. The experiment was divided into five parts: material synthesis and property testing, drug loading test, drug release test, in vitro studies and preliminary animal study. In order to avoid insulin denaturation, we develop a single step insHAP synthesis by hydrolysis of brushite (DCPD). insHAP size distribution is in the range of 865~1797 nm. Through XRD analysis, FTIR, SEM and TEM observations, we confirm that insulin is indeed inserted into hydroxyapatite lattice. TGA analysis shows the weight loss due to insulin decomposition is about 11.25%. BCA essay calculated drug loading of insHAP is 13.33% and drug entrapment efficiency is 86.08%. The drug release tests show insHAP only releases a small amount of insulin in the alkaline environment, which simulated the environment of general body fluids. On the other hand, hydroxyapatite was quickly degraded and had a great number of insulin release in the acidic environment, which simulated the environment inside lysosomes. In in vitro studies, WST-1 test shows there is no negative effect on cell viability and cell proliferation. The relatively low cytotoxicity of insHAP is proven by LDH test. Furthermore, we confirm by Cell TEM that insHAP could go through cellular uptake and get into lysosomes. Animal study indicates the blood glucose of STZ-induced diabetic Wistar rats after intramuscular injection of insHAP decreases slowly. It can maintain normal blood sugar for about 4-day period. Based on the above results, insHAP as insulin delivery model is a breakthrough for diabetes treatment. This novel drug delivery model will be potential in the future for carrying not only fluorescent protein, antibody, growth factor and other biological agents, but also cancer drugs for targeted therapy. This study offer s a new choice for protein drug delivery.
Subjects
drug delivery systems
diabetes
insulin
hydroxyapatite lattice
biomineralization
SDGs
Type
thesis
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