The purpose of this study was to design a submicron-sized liposomal non-steroidal antiinflammatory drug(NSAID)preparation that targets the retina via topical instillation of eye drops.Bromfenac(BRF)-loaded liposomes w...The purpose of this study was to design a submicron-sized liposomal non-steroidal antiinflammatory drug(NSAID)preparation that targets the retina via topical instillation of eye drops.Bromfenac(BRF)-loaded liposomes were prepared using the calcium acetate gradient method.Liposome sizes and encapsulation efficiencies were optimized by screening several liposome formulations of lipid,drug concentration,and buffer solution.BRF entrapment efficiency was greater than 90%using this method,and was low using conventional hydration methods.High initial BRF loading using the pH gradient method caused aggregation of liposomes.To circumvent aggregation,the negatively charged lipid dicetylphosphate was incorporated into liposomes,which formed anion layer preventing coalescence.Release of BRF from liposomes was sustained for several hours depending on lipid concentration,inner water phase,initial drug amounts,and surface properties.Surface modification with chitosan(CS),a mucoadhesive cationic polymer,was achieved using electrostatic interactions of negatively charged liposomes.The optimal concentration of CS for evasion of liposome aggregation was 0.15%.展开更多
文摘The purpose of this study was to design a submicron-sized liposomal non-steroidal antiinflammatory drug(NSAID)preparation that targets the retina via topical instillation of eye drops.Bromfenac(BRF)-loaded liposomes were prepared using the calcium acetate gradient method.Liposome sizes and encapsulation efficiencies were optimized by screening several liposome formulations of lipid,drug concentration,and buffer solution.BRF entrapment efficiency was greater than 90%using this method,and was low using conventional hydration methods.High initial BRF loading using the pH gradient method caused aggregation of liposomes.To circumvent aggregation,the negatively charged lipid dicetylphosphate was incorporated into liposomes,which formed anion layer preventing coalescence.Release of BRF from liposomes was sustained for several hours depending on lipid concentration,inner water phase,initial drug amounts,and surface properties.Surface modification with chitosan(CS),a mucoadhesive cationic polymer,was achieved using electrostatic interactions of negatively charged liposomes.The optimal concentration of CS for evasion of liposome aggregation was 0.15%.
文摘目的采用p H梯度法制备重酒石酸长春瑞滨长循环脂质体并进行表征。方法以粒径为指标,考察水化温度和挤出次数对空白脂质体粒径的影响;以粒径及包封率为指标,考察孵化温度和孵化时间对载药脂质体粒径和包封率的影响。并采用Malvern粒度仪测定脂质体的粒径分布、多分散系数及Zeta电位,透射电镜考察其形态,并考察脂质体稳定性。结果重酒石酸长春瑞滨长循环脂质体粒径(96.4±27.2)nm,多分散系数(0.162±0.042),Zeta电位(-26.7±3.5)m V;透射电镜显示脂质体粒径均一,成单层膜球状分布;长期稳定性研究显示,脂质体在5℃条件下放置3个月稳定。结论 p H梯度法可以用于重酒石酸长春瑞滨长循环脂质体的制备。
