Partition Behavior of Penicillin in Three-liquid-phase Extraction System

Partition behavior of penicillins G and V was studied in a novel three-liquid-phase extraction system,which is composed of butyl acetate (BA),polyethylene glycol (PEG),ammonia sulfate (NH4)2SO4 and water (H2O). The main components in the top,middle and bottom phases are butyl acetate,polyethylene glycol aqueous solution and ammonia sulfate aqueous solution,respectively. Some parameters such as partition coefficients Di/j and mass fractions Ei of penicillins G and V were determined at the room temperature,respectively. Experimental efforts have been made to investigate the partition behavior of penicillin in the three-liquid-phase extraction system,including initial concentrations of phase-forming components PEG and (NH4)2SO4,PEG molecular weight,pH,initial concentration of penicillin. The results indicated that penicillins G and V have the similar partition behavior. They preferentially distribute into the middle phase with the increase of initial concentration of phase-forming components and into the top phase with the decrease of pH,while partition coefficient Dm/b is hardly affected by pH value. The variation of PEG molecular weight has little effect on mass fractions of penicillin. The increase of initial concentration of penicillins G and V could lead to the increase of Dt/b,Dm/b and the decrease of Dt/m,while their mass fractions in all phases were almost independent on their initial concentrations.

Micellization,Interaction and Microenvironment in the Mixed Solution of Pluronics and Surfynol 104 with Nuclear Magnetic Resonance

The micellization,intermolecular interaction and microenvironment of molecular segments in the mixed aqueous solution of PEO-PPO-PEO triblock copolymer(Pluronic F88,P84 and P123) and Surfynol 104(S104) were studied by nuclear magnetic resonance method.The results showed that the addition of S104 decreased the critical micellization temperature of copolymer.When its concentration was 0.5 g/L,the most reduction was up to more than 10℃ for F88,which was most hydrophilic in the selected copolymers.This reduction was caused by the hydrophobic interaction between S104 molecules and PPO segments.The addition of S104 enhanced the hydration of PEO segments most obviously for P123.And S104 slightly increased the hydration of PPO segments before the micellization,but obviously decreased their hydration after micellization,which was attributed to the hydrophobic interaction mentioned above and temperature rising.This effect was most observable for F88.