Aqueous two-phase systems can be applied to a penicillin fermentation process to extract the produced penicillin from the fermentation broth to achieve a higher production rate. Such systems contain a polymer and a salt or two polymers. In this study, the liquid−liquid equilibrium of the quinary system of polyethylene glycol 6000, sodium sulfate, glucose, penicillin G, and water at 298.15 K is investigated. The experimental partition coefficients of glucose and penicillin-G showed the high efficiency of the present extractive fermentation processes. Using the liquid−liquid equilibrium data, the parameters of the NRTL activity model were calculated for the quinary system. The average absolute relative deviation of 0.677 % between experimental and calculated mass fractions shows that the NRTL activity model has a good ability to predict the equilibrium concentrations of the present system. In addition, a simple and accurate turbidimetric method for the measurement of penicillin G is proposed.
Background: Endoscopy is a diagnostic and therapeutic method with a high risk of nausea and vomiting. Considering the lack of adequate studies on the prevention of postoperative nausea and vomiting after endoscopy in children, this study was conducted to compare the effects of ondansetron, dexamethasone and a combination of these drugs on the reduction of nausea and vomiting in children aged 1 to 12 years undergoing upper gastrointestinal endoscopy.
Methods: In this double-blind, randomized clinical trial, 146 children aged 1 to 12 years, undergoing upper gastrointestinal endoscopy were randomly allocated to four groups of 36. Before endoscopy, the groups received 0.1 mg / kg of ondansetron, 0.2 mg / kg dexamethasone, a combination of the two drugs and placebo, respectively.
Results: According to the results of our study, children who underwent upper GI endoscopy, administration of ondansetron plus dexamethasone was associated with a significantly lower frequency of nausea in all assessment time points. However, the difference between the groups was significant only on admission to recovery and the 15 minutes after admission to recovery (P<0.001).
Conclusion: The results of our study indicated that in children undergoing endoscopy, the use of ondansetron plus dexamethasone is associated with reduction in the incidence of nausea and vomiting, and the use of the combination does not cause significant side effects compared to ondansetron, dexamethasone or placebo, separately.
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