Polymer-coated O/W Nanoemulsions Prepared By One Step Phase Inversion Temperature Method

Nanoemulsion is widely used in petroleum,food,cosmetics and medicine because of its good fluidity,stable storage,large specific surface area and high drug permeability.The positively charged nanoemulsions is proven to be able to enhance the absorption and targeted release of drugs,which is therefore widely used in the new pharmacy and drug transportation.However,the transportation of anticancer drug carrier system with positively charge tend to stick to the surface of red blood cells and plasma proteins,in the delivery process,which is not conducive to the absorption and utilization of drugs by cancer cells.Therefore,it is of great significance to develop a nano-drug delivery system that is negatively charged in the blood transport but positively charged in the tissues of cancer cells.More and more researchers are working on charge reversal nano-drug delivery systems.The pH of normal human tissues is 7.4,while that of cancer tissues is 5-6.8.According to this difference,pH-triggered charge reversal drug carriers can be prepared.Polymers have attracted much attention in many fields such as food,water treatment and biomedicine because of their good hydrophilic and electrostatic properties.The polymer can be combined with other surfactants to stabilize the emulsion,adhere to the surface of the emulsion by electrostatic or hydrogen-bond interactions,and modify the nanoemulsion.However,the preparation of Polymer coated nanoemulsion by conventional mechanical method and two step method requires large amount of energy input which limits its commercial applications.Therefore,the preparation of polymer-coated nano-emulsion by one-step phase inversion temperature(PIT)method has important theoretical significance and application value.Based on the above research background,this paper studied the influence of different polymers on the PIT of water/span80/tween80/liquid paraffin system.We prepared a cationic polymer-coated positively charged O/W nanoemulsion using one-step PIT method and investigated the effect of polymer concentration on the particle size(DH)and polydispersity index(PDI),zeta potential,rheological properties and long-term stability of nanoemulsions.It mainly includes the following three parts:In the first part,we studied the effects of cationic polymer PDADMAC and chitosan on the PIT of water/Span80/Tween80/liquid paraffin system phase.We prepared a cationic polymer-coated positively charged O/W nanoemulsion using a one-step PIT methodandinvestigated the effect of polymer concentration on the particle size(DH)and polydispersity index(PDI),chargeability(zeta potential),rheological properties and long-term stability of nanoemulsions.The addition of cationic polymer reduces the PIT of the emulsion system.The average DH and PDI of nanoemulsions containing sufficient polymer are 150nm and 0.15,respectively.The zeta potential of PDADMAC-coated nanoemulsion is up to +40mV,and the zeta potential of chitosan-coated nanoemulsion is up to +50mV.The DH and PDI of the emulsion did not change after storage for 90 days at room temperature.In addition,we prepared a SDS-stabilized cationic polymer nanoemulsion by two-step ultrasonic method.The DH,PDI and zeta potentials of the nanoemulsion ranged from 300 nm to 500 nm,0.2 to 0.4 and +50 mV to +60 mV,respectiely.The stability of these nanoemulsions is poor.Compared with the two-step high energy method,the one-step PIT method is an effective method for preparing high internal phase positively charged nanoemulsionIn the second part,we studied the influence of anionic polymer PSS and PAAS on the PIT of water/Span80/Tween80/liquid paraffin system,and investigated the effects of PSS and PAAS on nanoemulsion.The anionic polymer reduced the PIT of the emulsion system.The average DH,PDI and zeta potentials of the nanoemulsions containing sufficient anionic polymer were 125 nm,0.8 and-50 mV,respectively.The DH and PDI of the nanoemulsions droplet did not change after 90 days,which indicating nanoemulsions have good stability.In the third part,we studied the effects of the PEI10000 and PEI70000(10,000 and 70,000 are molecular weight)on the PIT of water/Span80/Tween80/liquid paraffin system,and prepared the PEIioooo and PEI70000 coated charge-reversed nanoemulsion by one-step PIT method.PEI10000 and PEI70000 increase the PIT and the viscosity of the system.The average DH and PDI of PEI 10000 nanoemulsions are 130nm and 0.1,respectively.When PEI10000 concentration is 0.112wt%-0.314wt%and pH is 7.4,zeta potential is-20mV?-5.6mV,and when pH is 6.1,zeta potential is +40mV?+46mV.PEI70000 make system PIT above 100?,PIT can be reduced by reducing the ratio of oil to surfactant.We have prepared the charge-reversed nanoemulsion with a concentration of PEI70000 less than 0.2wt%.