Mohammad Sirousazar; Helga Zebardast; Zeinab Hosseini Dastgerdi; Farshad Kheiri
Volume 13, Issue 4 , December 2019, , Pages 349-360
Abstract
In this research, the response of a novel drug delivery system responsive to the temperature, as a unique stimulus, was studied. The performance of the system was modeled at the unsteady state, using the numerical method. The system has three individual layers, containing a drug core, a phase-transient ...
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In this research, the response of a novel drug delivery system responsive to the temperature, as a unique stimulus, was studied. The performance of the system was modeled at the unsteady state, using the numerical method. The system has three individual layers, containing a drug core, a phase-transient intermediate layer and an external protective layer. The system has the ability to start and stop the release of the drug, according to the On-Off mechanism, by exerting any changes in the temperature of the release medium. Mathematical modeling was performed by solving the heat and mass transfer equations governing the layers of the system at the unsteady state. The lag time of system at On state, the drug release kinetics at On state and undesired drug release kinetics at Off state were determined as functions of the parameters of the system. The results obtained from the modeling showed that response of the system was under the influence of different parameters, such as the geometry of the system, the kind of constituents of the intermediate and protective layers and the ratio of the thermal conductivity of the intermediate layer at molten state to the thermal conductivity of the protective layer. It was shown that a reduced lag time for the system could be achieved by manipulating these parameters. From the viewpoint of the drug release kinetics at On state, it could be declared that the amount of the released drug is a function of the time constant of the system and the drug release could be increased by decreasing the time constant value. The results also showed that the undesired release of the drug could be accelerated by adjusting the parameters of the protective layer, such as the kind of constituents and the thickness of the layer. Using the obtained results from the numerical modeling, one can design and produce the temperature-responsive smart drug delivery systems with desired characteristics for practical applications.
