目的以L-丝氨酸为亲水部分、1,8-辛二胺为疏水部分,合成一种新型Bola型表面活性剂1,8-辛烷二丝氨酸(1,8-serine diaminooctane,DAOS),并测定了其p Ka值和临界胶束浓度(critical micelle concentration CMC),进而预测其在水溶液中的聚集行为,探讨其作为药物载体的潜在优势。方法通过酯化生成酰胺和HCl脱去保护基两步反应,成功合成DAOS。采用IR法、质谱法和1H-NMR法对其结构进行表征。采用电位滴定法测得其p Ka值,采用电导率法和芘荧光探针法测定DAOS水溶液的临界胶束浓度(CMC)。结果目标产物DAOS产率为91.01%,IR法、质谱法和1H-NMR法表征证明DAOS合成成功。p Ka1为(2.964±0.031),p Ka2为(6.751±0.148)。在20℃时,电导率法测得CMC为0.10 mmol·L^-1,随温度升高CMC逐渐增大。芘荧光探针法测得CMC近似为0.14 mmol·L^-1。结论制备的新型Bola型表面活性剂,具有作为p H值敏感载体的前景,对其CMC的测定为其进一步作为药物载体提供理论依据。
Objective To synthesis the novel Bola amphiphile 1,8-serine diaminooctane( DAOS),L-serine and 1,8-diaminooctane were employed as the hydrophilic part and hydrophobic part,separately. Its p Kaand critical micelle concentration( CMC) were investigated to predict its self-assemble ability and discus the potential property as drug carrier. Methods The structure of DAOS was characterized by IR,MS and1H-NMR. The p Kawas measured by acid-base titration. The critical micelle concentration( CMC) of DAOS in water was determined by conductivity and pyrene fluorescence spectroscopy. Results The yield of DAOS was 91. 01%. As a diprotic weak acid,its p Kawere( 2. 964 ± 0. 031) and( 6. 751 ± 0. 148),respectively.The CMC of DAOS was about 0. 10 mmol·L^-1by the conductivity method at 20 ℃. With the increase of temperature,the CMC value tended to increase a little. The results of the two methods were different. The pyrene fluorescence spectroscopy was 0. 14 mmol·L^-1. Conclusions The novel Bola amphiphile derived from serine showed a potential application as p H-sensitive carrier. The measurement of CMC can provide a theoretical basis in drug delivery for future study.