Stability Study of Chloramphenicol in Polyoxy-ethylated Nonionic Surfactant-Water System
|Keywords||Chloromycetin ~ 1H-NMR Hydrolysis Dynamics Stability Quantum chemistry|
Chloramphenicol eye drops are widely used, broad market prospects. But chloramphenicol unstable in aqueous solution, prone amide hydrolysis reaction. Thus improving the stability of the chloramphenicol in the aqueous solution, to improve the quality of chloramphenicol eyedrops significance. This article the Gaussian software chloramphenicol and formamide geometry optimization in water solvent venue, chloramphenicol and charge distribution of formamide, explain the reason the chloramphenicol prone amide hydrolase reaction. Studied the hydrolysis kinetics of the boric acid - borax buffer solution of chloramphenicol, chloramphenicol hydrolysis rate equation. The study found that the reaction temperature was increased by 7 ° C, the hydrolysis reaction rate increased about twice as described chloramphenicol hydrolysis process is sensitive to temperature. The thesis adopts 1H-NMR chloramphenicol solubilizing location and a small amount of water within the different polyoxyethylene-type surfactant micelles in the surface active agent in the presence of state. The results showed that in surfactant micelles, chloramphenicol molecules should be arranged for the orientation, and its lipophilic portion is solubilized in the micellar palisade layer structure, the hydrophilic portion is solubilized in the micelle polyoxyethylene structure. Tween -80 and AEO-10 ??system in the reverse micelle is formed, and the mass fraction of water is 2.8% TX-13 and EL-40 system is difficult to form a reverse micelle. The paper studies the hydrolytic stability of chloramphenicol in different polyoxyethylene surfactant - water system. Chloramphenicol in the polyoxyethylene-type surface active agent - water system the water phase and the micelle phase exists balanced distribution. Of chloramphenicol by chloramphenicol in the buffer solution, the hydrolysis behavior of the hydrolysis process in an aqueous phase containing a small amount of moisture in surface active agent in the hydrolysis behavior of chloramphenicol by chloramphenicol in micellar phase hydrolysis process. The results show that the hydrolysis rate constant of the chloramphenicol in the micellar phase is only in the water phase within 1/50 to 1/10, the stabilizing effect of surfactants to chloramphenicol is the chloramphenicol solubilized micellar phase, reducing the rate of hydrolysis reaction. The paper also discusses the polyoxyethylene type surface active agent of chloramphenicol stabilizing effect with a surfactant molecular structure of the relationship between the. The results showed that a polyoxyethylene type surface active agent molecules in the ethylene oxide chain section adduct the stability of the effect of the degree of chloramphenicol smaller, affecting the stability of the lipophilic structure of chloramphenicol was significant, and the lipophilic group Tween-80 and EL of the long-chain branched structure is conducive to the chloramphenicol stability was improved.