Pyrolysis characteristics of radix rhizoma rhei, cortex moudan radicis, and radix sanguisorbae and correlations with the carbonizing process of Chinese herbs / 中国天然药物

AIM@#The aim of the work is to study the pyrolysis characteristics of radix rhizoma rhei, cortex moudan radicis, and radix sanguisorbae in an inert atmosphere of argon (Ar), and to investigate the mechanism of the carbonizing process of the three traditional Chinese herbs.@*METHODS@#The pyrolysis characteristics of the crude materials and their extracts were studied by thermogravimetry-mass spectrometry (TG-MS) in a carrier gas of argon, coupled with Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM) methods. Correlation of the pyrolysis behaviors with the carbonizing process by stir-frying of traditional Chinese medicines was made.@*RESULTS@#Within the temperature range of 200-300 °C, which is the testing range for the study of the carbonizing process of Chinese herbs, the temperatures indicated by the maximum weight loss rate peak of the above three extracts were taken as the upper-limit temperatures of the carbonizing process of the herbs, and which were 200, 240 and 247 °C for radix rhizoma rhei, cortex moudan radicis, and radix Sanguisorbae, respectively. The ion monitoring signal peaks detected by the TG-MS method corresponded with reports that the level of chemical components of traditional Chinese medicinal materials would decrease after the carbonizing process. It was confirmed by Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM) methods that better results of "medicinal property preservation" could be obtained by heating at 200 °C for radix rhizoma rhei, at about 250 °C for cortex moudan radicis, and radix sanguisorbae, as the relative intensity values of the common peaks were among the middle of their three carbonized samples by programmed heating.@*CONCLUSION@#The upper-limit temperatures of the carbonizing process for radix rhizoma rhei, cortex moudan radicis and radix sanguisorbae were 200, 240 and 247 °C respectively. It is feasible to research the mechanism and technology of the carbonizing process of traditional Chinese medicinal materials using thermogravimetry, Fourier transform infrared spectrometry, and scanning electron microscopy methods.

Mixed nanomicelles loaded with thymopeptides-sodium deoxycholate/phospholipid improve drug absorption / 中国天然药物

AIM@#To improve the absorption of thymopeptides (TH) by preparing sodium deoxycholate/phospholipid-mixed nanomicelles (SDC/PL-MMs).@*METHODS@#TH-SDC/PL-MMs were prepared by a film dispersion method, and then evaluated using photon correlation spectroscopy (PCS), zeta potential measurement, as well as their physical stability after storage for several days. Furthermore, in situ intestinal single-pass perfusion experiments and pharmacodynamics in immunodeficient mice were performed to make a comparison with TH powders and the control drug in absorption properties.@*RESULTS@#A narrow size distribution of nanomicelles, with a mean particle size of (149 ± 8.32) nm and a zeta potential of (-31.05 ± 2.52) mV, was obtained. The in situ intestine perfusion experiments demonstrated a significant advantage in absorption characteristics for TH compared to the other formulations, and oral administration of TH-SDC/PL-MMs potentiated an equivalent effect with i.h. TH in pharmacodynamic studies in immunodeficient mice.@*CONCLUSIONS@#TH-SDC/PL-MMs prepared by a film dispersion method are able to improve the absorption of TH. SDC/PL-MMs might be a good approach for the more effective delivery of drugs like TH.

Characterization and evaluation in vivo of baicalin-nanocrystals prepared by an ultrasonic-homogenization-fluid bed drying method / 中国天然药物

AIM@#To improve the absorption and bioavailability of baicalin using a nanocrystal (or nanosuspension) drug delivery system.@*METHODS@#A tandem, ultrasonic-homogenization-fluid bed drying technology was applied to prepare baicalin-nanocrystal dried powders, and the physicochemical properties of baicalin-nanocrystals were characterized by scanning electron microscopy, photon correlation spectroscopy, powder X-ray diffraction, physical stability, and solubility experiments. Furthermore, in situ intestine single-pass perfusion experiments and pharmacokinetics in rats were performed to make a comparison between the microcrystals of baicalin and pure baicalin in their absorption properties and bioavailability in vivo.@*RESULTS@#The mean particle size of baicalin-nanocrystals was 236 nm, with a polydispersity index of 0.173, and a zeta potential value of -34.8 mV, which provided a guarantee for the stability of the reconstituted nanosuspension. X-Ray diffraction results indicated that the crystallinity of baicalin was decreased through the ultrasonic-homogenization process. Physical stability experiments showed that the prepared baicalin-nanocrystals were sufficiently stable. It was shown that the solubility of baicalin in the form of nanocrystals, at 495 μg·mL(-1), was much higher than the baicalin-microcrystals and the physical mixture (135 and 86.4 μg·mL(-1), respectively). In situ intestine perfusion experiments demonstrated a clear advantage in the dissolution and absorption characteristics for baicalin-nanocrystals compared to the other formulations. In addition, after oral administration to rats, the particle size decrease from the micron to nanometer range exhibited much higher in vivo bioavailability (with the AUC(0-t) value of 206.96 ± 21.23 and 127.95 ± 14.41 mg·L(-1)·h(-1), respectively).@*CONCLUSION@#The nanocrystal drug delivery system using an ultrasonic-homogenization-fluid bed drying process is able to improve the absorption and in vivo bioavailability of baicalin, compared with pure baicalin coarse powder and micronized baicalin.