A sphere-shaped drug delivery system responsive to temperature, as a unique external stimulus, was introduced and its performance mathematically studied at the pseudo-steady state. The system is composed of three individual sections, including the drug core, phase-transient intermediate shell, and protective polymeric shell. An ON-OFF release of drug could be achieved by increasing or decreasing the environmental temperature around the melting point of the intermediate shell and the smartness of system is due to the solid-liquid phase transition of this shell. The ON-OFF response of the system was mathematically modeled by solving the governing heat and mass transfer equations at the pseudo-steady state. The results showed the lag time of the system in the ON state, the cumulative released drug in the ON state and the fractional undesired release of drug in the OFF state are strongly under the influences of different kinds of factors, including the geometrical characteristics of the system (e.g., the radius of the drug core and the thicknesses of the intermediate and polymeric shells), the physical properties of the system (e.g., the thermal conductivities and diffusion coefficients of the intermediate and polymeric shells), and the environmental and operation conditions.

作为独特的外部刺激，引入了一种对温度响应的球形药物输送系统，并在拟稳态下对其性能进行了数学研究。该系统由三个独立的部分组成，包括药芯，相变中间壳和保护性聚合物壳。可以通过在中间壳的熔点附近提高或降低环境温度来实现药物的ON-OFF释放，并且系统的灵巧性是由于该壳的固-液相转变造成的。通过求解伪稳态下的控制传热和传质方程，对系统的开-关响应进行数学建模。结果表明，系统处于打开状态的滞后时间，