Shakers kinetic measurements

The drug desorption kinetics is extremely important for application of the adsorbents as anti-cancer drug carriers. One milligram per milliliter of FC-4 particles were mixed with 100 pg/ml solution of doxorubicin, sonicated for 2 min and incubated on a shaker for 2.5 h. The particles were then sedimented in a centrifuge, the supernatant was removed, and the pellet of FC-4 loaded with doxorubicin was re-suspended in human blood serum at the same concentration as that of the initial doxorubicin solution. The mixture was incubated on a shaker at 37°C. Samples were taken at 6 h intervals for the first 3 days and daily thereafter, the adsorbent particles were removed by magnetic sedimentation and the optical density of the supernatant was measured at 296 nm. The concentration of the drug in solution was calculated. 

Procedure. For most reactions, measured amounts of clay and waste solution were mixed thoroughly in polypropylene bottles. The bottles were then sealed and placed in a constant temperature oven (Blue M Electric Co.), shaker bath (Precision Scientific Co.), or boiling water bath for a specified time. For kinetic experiments the clay and waste solutions were allowed to reach the desired temperature overnight. Waste solution was measured and added to the clay using a preheated plastic... 

Measurement of Xylose Isomerization Kinetics and Equilibrium All experiments were carried out at 34 °C in a volume of 25 ml in 50-ml shake flasks agitated at 130 rpm in an incubated shaker. Each experiment was conducted in duplicate. All experiments used 60 g/ 1 xylose, and unless otherwise noted, 5.2 g/1 of enzyme pellets (0.13 g) was used for each experiment. Buffered solutions used in making the isomerization media were 0.01 M Tris buffer (pHed to 7.5 using 0.01 M NaOH) and 0.05 M sodium citrate buffer (pHed to 4.5 using citric acid). The pH was measured at the beginning of the experiments but was not monitored throughout. We have observed a small drift in pH of less than 1 unit over the course of 48 hrs. Even with this drift, the pH of the bulk solution stayed within the range suitable for fermentation and well-below the pH optimum of XI (pH 7.5). In experiments with co-inunobilized pellets, urea concentration was 0,0.01, or 0.1 M. 

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