Yiqiao Xie1, Jisheng Chen2, Shu Zhang3, Kaiyan Fan4, Gang Chen5, Zerong Zhuang6, Mingying Zeng7, De Chen8, Longgui Lu9, Linlin Yang10, Fan Yang11. 1. Department of Pharmaceutics, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, China. Electronic address: 15002013083@163.com. 2. Department of Pharmacy, First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, China. Electronic address: cjslym@163.com. 3. Department of Pharmaceutics, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, China. Electronic address: zzss_97@163.com. 4. Department of Pharmaceutics, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, China. Electronic address: 412787243@qq.com. 5. Department of Pharmaceutics, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, China. Electronic address: cg753@126.com. 6. Department of Pharmaceutics, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, China. Electronic address: 1091318015@qq.com. 7. Department of Pharmaceutics, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, China. Electronic address: 378156445@qq.com. 8. Department of Pharmaceutics, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, China. Electronic address: 496806331@qq.com. 9. Department of Pharmaceutics, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, China. Electronic address: 215496932@qq.com. 10. Guangdong Province Maternity and Child Care Hospital, Guangzhou, Guangdong 510006, China. Electronic address: Fy_yanglinlinlin@126.com. 11. Department of Pharmaceutics, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, China. Electronic address: gzyangfan@hotmail.com.
Abstract
PURPOSE: This paper discussed the influence of microstructure of emulsion membrane on O/W emulsion stability. METHODS: O/W emulsions were emulsified with equal dosage of egg yolk lecithin and increasing dosage of co-emulsifier (oleic acid or HS15). The average particle size and centrifugal stability constant of emulsion, as well as interfacial tension between oil and water phase were determined. The microstructure of emulsion membrane had been studied by (1)H/(13)C NMR, meanwhile the emulsion droplets were visually presented with TEM and IFM. RESULTS: With increasing dosage of co-emulsifier, emulsions showed two stable states, under which the signal intensity of characteristic group (orient to lipophilic core) of egg yolk lecithin disappeared in NMR of emulsions, but that (orient to aqueous phase) of co-emulsifiers only had some reduction at the second stable state. At the two stable states, the emulsion membranes were neater in TEM and emulsion droplets were rounder in IFM. Furthermore, the average particle size of emulsions at the second stable state was bigger than that at the first stable state. CONCLUSIONS: Egg yolk lecithin and co-emulsifier respectively arranged into monolayer and bilayer emulsion membrane at the two stable states. The microstructure of emulsion membrane was related to the stability of emulsion.
PURPOSE: This paper discussed the influence of microstructure of emulsion membrane on O/W emulsion stability. METHODS: O/W emulsions were emulsified with equal dosage of egg yolk lecithin and increasing dosage of co-emulsifier (oleic acid or HS15). The average particle size and centrifugal stability constant of emulsion, as well as interfacial tension between oil and water phase were determined. The microstructure of emulsion membrane had been studied by (1)H/(13)C NMR, meanwhile the emulsion droplets were visually presented with TEM and IFM. RESULTS: With increasing dosage of co-emulsifier, emulsions showed two stable states, under which the signal intensity of characteristic group (orient to lipophilic core) of egg yolk lecithin disappeared in NMR of emulsions, but that (orient to aqueous phase) of co-emulsifiers only had some reduction at the second stable state. At the two stable states, the emulsion membranes were neater in TEM and emulsion droplets were rounder in IFM. Furthermore, the average particle size of emulsions at the second stable state was bigger than that at the first stable state. CONCLUSIONS: Egg yolk lecithin and co-emulsifier respectively arranged into monolayer and bilayer emulsion membrane at the two stable states. The microstructure of emulsion membrane was related to the stability of emulsion.