Preliminary Study Of The Smart Capsule For Drug Delivery System Based On PH Testing

In recent years, the new technology of Human Drug Absorption (HDA) has became extraordinary brighten in the international pharmaceutical field, it mainly focuses on the drug absorption problem in the digestive tract, also it can provide some important and basic data for the early development of a new drug. With the traditional method, the researchers obtain the drug absorption data by intubating and douching, which would bring discomforts and traumas to the patients or even destroy the normal function of the digestive tract, thus the accuracy of measuring results would inevitably be affected. A new non-invasive method used for human drug absorption (HDA) was proposed in this study, which was the smart capsule system for drug delivery, based on pH testing. The pH value of the gastrointestinal tract (GI) was measured, and the drug could be released by Site-Specific Delivery Capsule (SSDC). The working principle was below: as the pH sensor detected pH values in the gastrointestinal tract, the microprocessor determined whether the measured pH values met the requirements of internal programs, once the measured pH value met the requirements, the microprocessor would trigger the drug release module, then the drug was released. Since that, some human blood was collected after periods of time for analysis, and the drug concentration-time curve could be drawn. The capsule system has characteristics of non-invasive, intelligence, real-time, low power consumption.The paper contained mainly four parts. First, we chose antimony electrode as the human gastrointestinal tract pH sensor, designed and produced the structure of antimony electrode. The performances of antimony electrode were tested in vitro experiments; the experiments results showed that the sensitivity of antimony electrode was 43.5mv/pH. It had a fast response time, which met the need for pH measuring in the gastrointestinal tract. The results also showed the trigger voltage stored in the micro controller unit (MCU), which was from 113.1 to 282.8 mv. Second, we chose the PIC12F683 as microprocessor chip, completed the circuit design and software design of microprocessor chip. The software design implemented some functions, for example, the microprocessor chip would test pH values at intervals of 5 second, the 5 second was in the sleep mode, and internal program in the microprocessor chip would analyze and calculate the measured pH value. The pH measuring module was also tested in vitro experiments to verify its effects, the results showed the capsule could release the drug in a certain pH range according to the change of pH value. Third, we fulfilled the design of power management module with a magnetic switch. The power module would supply power to each module under the control of the magnetic switch. Four, we completed the design of micro-thruster in the drug delivery module, and the selection of ignition agents and propellants. At the same time, the drug delivery module was tested, the experiments showed that the micro-thruster can generate enough thrust under the action of the ignition, implying that it can be used in the drug delivery module.The capsule system is with important application value in the dynamics of pharmaceutical metabolism and human drug absorption for new drugs'developments. It can be used not only be used in the new chemical drug development, providing a new drug research approach for the pharmaceutical companies, but also to study the absorption of Chinese medicine and its main role composition in different pH circumstances after further improvement, providing a innovative research method for pharmacology of Chinese medicine.