[Formulation Optimization of Zuojin Floating-Bioadhesive Pellets by Central Composite Design-Response Surface Methodology].

OBJECTIVE: To optimize the formulation of Zuojin floating-bioadhesive pellets by the central composite design-response surface methodology (CCD-RSM). METHODS: In the formulation design using CCD-RSM, independent variables were the amounts of sodium bicarbonate (X1), HPMC (X2) and MCC (X3) as factors. Small pills roundness, 12 h floating rate and the percentages of in vitro cumulative releases at 2,6 and 12 h were dependent variables. Multilinear and quadratic model were used to estimate the relationship between the dependent and the independent variables. According to best model, the contour plots and RSM were drawn, and the optional formulation was selected. According to the optional formulation,the pellets were prepared and validated. RESULTS: The quadratic was the best fitting mode. Small pills roundness was 15.04 °. 12 h floating rate was 75.07%. Percentages of in vitro cumulation release at 2,6 and 12 h of the option formulation pellets was 27.01%, 70.00% and 84.61%, respectively. The actual value was close to the predicted value. Deviation was less than 5%. CONCLUSION: Quadratic model was preferred in the optimization of formulation due to the statistical confidence. The multi-objective simultaneous optimization of Zuojin floating pellet formulation can be achieved by the central composite design-response surface methodology.

Lysis of Microcystis aeruginosa with extracts from Chinese medicinal herbs.

Boiling water extracts of 66 selected Chinese medicinal herbs were screened for their anticyanobaterial activity against Microcystis aeruginosa by the soft-agar overlayer (SAO) method. Results indicated that extracts from 16 materials could inhibit the growth of this bacterial species. Among these anticyanobacterial samples, eight extracts showed low minimum inhibitory concentrations (MIC), including four extracts with MICs between 1 and 6 mg/mL, and four extracts with MICs < 1 mg/mL which could be considered useful to prevent the outbreak of cyanobacteria before the appearance of cyanobacterial blooms. Further study showed that three extracts with MIC values < 1 mg/mL induced intensive chlorophyll-a lysis within 7 days at the MIC. The results suggested that highly efficient anticyanobacterial compounds must be involved in the inhibitory activities. The final results indicated these three extracts (from Malaphis chinensis, Cynips gallae-tinctoriae and Fructus mume) had the potential to be developed as algicides due to their remarkably anticyanobacterial activities.