Microcalorimetric Investigation of Toxic Effects of Three Injectable Solubilizing Excipients on Tetrahymena thermophila BF5 Growth

用 microcalorimetry， Tetrahymena thermophila BF5 的热新陈代谢的曲线(T。thermophila BF5 ) 在 28 点的生长 ? 業牣杯慲桰?

Using microcalorimetry, thermal metabolic curves of Tetrahymena thermophila BF5 （T. thermophila BFs） growth at 28℃ affected by three injectable solubilizing excipients （ISE） including tween 80, hydroxypro- pyl-β-cyclodextrin （HP-β-CD） and poloxamer 188 were measured. Meanwhile, the toxicities of three ISE were evaluated by dynamic parameters of thermal metabolic curves. In addition, the irritative effects of the ISE on myoblast L6cells were investigated to show their cytotoxicities by biochemical method. The results indicated that the effects of the ISE on T. thermophila BF5 varied for different ISE. 5% inhibition concentration values （IC5） of the ISE were 1.33, 1.83 and 1.64 mg/mL for tween 80, HP-β-CD and poloxamer 188, respectively. By the principal component analysis （PCA）, the total quantity of heat （Q）, growth rate constant （k） and second maximum power （P2） were selected as the main characteristic parameters to present their toxicities, there were good linear relationships between Q, k, P2 and concentrations c, suggesting that the toxicities of the ISE on T. thermophila BF5 were closely linked to their concentrations. The results of creatine kinase （CK） bioassay of myoblast L6 cells indicated that the sequence of irritative effects of the ISE was HP-β-CD〈poloxamer 188〈tween 80, which added to the results ob- tained from microcalorimetry.