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Different kind of drugs can be loaded into the porous silicon microparticles for oral dosing. In cases where the drug is in its crystalline form in the pores, the amount of the loaded drug can be determined accurately using a calorimetric method, thermoporometry. Even if the drug substance is not in crystalline form a sophisticated estimation can be given. In this work ibuprofen, antipyrine, and ranitidine have been studied. Ibuprofen and antipyrine were easily detected and quantified, but ranitidine, which does not penetrate into the PSi microparticles in its crystalline form, could only be qualitatively determined. The possibility to quantify this kind of drug substance is also discussed.

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Thermal carbonization of porous silicon (PSi) by acetylene has shown good stability against ageing and it also maintains a large spesific surface area of the PSi. Therefore, thermally carbonized porous silicon (TCPSi) is appropriate for humidity sensing applications. Hysteresis occurs, when water condenses into the pores of hygroscopic media, e.g. in the oxidized PSi. In the case of TCPSi, the hygroscopicity can be tuned by the treatment temperature and both a hydrophilic and hydrophobic surface can be obtained. Hysteresis can be reduced, when condesation is dimished. In this work, hygroscopicity of various PSi samples carbonized at different temperatures were studied. Contact angles and pore size distributions of differently treated samples were determined.

Thermal carbonization of porous silicon (PS) at 820 °C under acetylene atmosphere is an appropriate method for humidity sensing purposes. It produces stable and hydrophilic surface still maintaining originally large specific surface area of PS. We report the temperature dependence of various electrical parameters measured for the thermally-carbonized PS humidity sensor. Capacitance of the sensor in dry air (6 RH%) is almost constant at various temperatures, whereas in higher relative humidity values, the temperature dependence becomes evident. The resistance variation of the sensor is less dependent on RH as the temperature increases. While the capacitance showed linear behavior as a function of temperature, the resistance had a clear non-linear temperature dependence. In order to get information about the effects of frequency on capacitance values, we measured a phase angle and admittance of the sensor as a function of frequency at three different temperatures in low and high humidity. According to these results, it is preferable to operate this sensor construction using low frequency (<1 kHz).

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