A Study Of Nano-calamine

Calamine and Shengji-Babao-San (SBS) have been used for treating chronic skin ulcer during the past thousands of years. However, the application of calamine was limited because calamine is hardly dissolved and its particles are too big. The application of SBS was also limited because calomelas, as an antibacterial component in SBS, has a severe toxicity. It is very necessary to improve the bioavailability of calamine and the safety of SBS. In this study, preparation, characteristic and antibacterial activity of nano-calamine and its substitutable effect for calomelas in SBS were investigated with the support of Bureau of Science and Technology, Shenzhen. The main results are as follows: 1. The relationship between the results and the methods of handing nano-calamine in measurement on particle size and size distribution was studied by dynamic laser scatting. The results showed that the better dispersing medium was 0.2% sodium phyphosphate, the better concentration of nano-calamine was 0.1 mg/mL and it was better for disruption time within 2~5 min, and for depositing time within 5~10 min. The repeatability of size and size distribution measurement of nano-calamine was good. 2. Preparation technics of nano-calamine were also studied in this paper. A series of ball milling test was conducted under different conductions such as different rotating speed, ball material ratio, ball milling media and milling time. It was found that the effect of ball milling could be improved when proper ball milling media, high turning speed, about 60% ball material ratio. It was also found that the peculiar phenomenon of "counter-grinding"in the grinding process with the ball milling time increasing. 3. The antibacterial activities of nano-calamine and calamine were evaluated by the disc method and the twofold agar dilution method. Nano-calamine showed a significant enhancement of antibacterial activity compared with calamine against all the tested bacteria. SBS demonstrated an inhibition diameter 17.4±0.5 mm, compared with it, SBS containing nano-calamine had a 4 mm increase, but SBS without calomelas had a 6 mm decrease against S. aureus. For P. aeruginosa the inhibiting diameter of SBS without calomelas and SBS containing nano-calamine was 8.4±0.3 mm, 7.2±0.2 mm, 11.0±1.0 mm respectively. The results of MIC and MBC values were consistent with that of antibacterial activity. So it is concluded that nano-calamine may be a prospective substituted for calomelas in SBS.