共载5-氨基酮戊酸及二氧化碳的氟碳微乳凝胶的制备及质量评价

Preparation and quality evaluation of fluorocarbon microemulsionbased gel loaded with both 5-aminolevulinic acid and carbon dioxide

为提高5-氨基酮戊酸(5-aminolevulinic acid,5-ALA)介导的光动力治疗(photodynamic therapy,PDT)的疗效,本研究制备了共载5-ALA及二氧化碳(CO_(2))的氟碳微乳凝胶(fluorocarbon microemulsion-based gel,FMBG)。通过表征其平均粒径、zeta电位、形貌和pH值等考察其理化性质;利用酸碱中和滴定的方法测定CO_(2)的装载量;建立荧光衍生化法测定5-ALA含量;通过激光共聚焦显微镜及Franz扩散池测定装载5-ALA的FMBG的体内外扩散情况;通过激光散斑血流成像仪测定CO_(2)增加血流灌注的情况;最后通过苏木精-伊红染色法(hematoxylin-eosin staining,H&E)检测载药FMBG的皮肤刺激性。结果表明,所制备的FMBG呈乳白色凝胶状,平均粒径为202.4 nm,zeta电位为-25.3 mV,pH值为6.0,黏度为1062.0 mPa·s,且室温下可以稳定保存7天;测得5-ALA含量约为20%(w/w);在室温、常压下,CO_(2)的装载量为5.016 mg·L^(-1),是相同量水溶液对CO_(2)装载量的1.5倍;透皮吸收实验及血流灌注实验结果表明,FMBG可有效实现5-ALA和CO_(2)的经皮递送,并显著增加皮肤的血流灌注;H&E染色证明,载药FMBG的皮肤刺激性较小(动物实验已获联勤保障部队第九〇〇医院伦理委员会批准)。综上,本研究成功制备了共载5-ALA及CO_(2)的FMBG,安全稳定,适合开发成经皮给药制剂,有望显著增强PDT疗效。

To improve the efficacy of 5-aminolevulinic acid(5-ALA)-mediated photodynamic therapy(PDT),a fluorocarbon microemulsion-based gel(FMBG)loaded with both 5-ALA and carbon dioxide(CO_(2))was prepared in this study.Its physical and chemical properties such as particle size,zeta potential,morphology,pH value and viscosity were characterized.Acid-base titration experiment was used to determine the CO_(2) loading,a fluorescence derivatization method was established to determine the content of 5-ALA,and the confocal laser scanning micro‐scope and Franz diffusion cell method were carried out to investigate its transdermal ability.Through the laser speckle contrast imaging,the CO_(2)-affected blood flow perfusion of skin was measured.Finally,the skin irritation test was tested by hematoxylin-eosin staining(H&E)method.These results showed that the prepared FMBG was a milky white gel,with an average particle size of 202.4 nm,a zeta potential of-25.3 mV,a pH of 6.0,and a viscosity of 1062.0 mPa·s.It can be stored stably for seven days at room temperature.The 5-ALA content of FMBG was measured to be approximately equal to 20%(w/w).At room temperature and normal pressure,the CO_(2) loading content of FMBG was 5.016 mg·L^(-1),which was 1.5 times as much as that of water.The transdermal absorption experiment and blood perfusion results showed that the FMBG can effectively enable the transdermal delivery of 5-ALA and CO_(2),and significantly increased the blood perfusion of skin.H&E staining results indicated that FMBG had negligible skin irritation(all animal tests were approved by the Ethics Committee of 900 Hospital of the Joint Logistics Team).In this study,a safe and stable FMBG loaded with both 5-ALA and CO_(2) was successfully prepared.It was suitable for transdermal application,having the potential of enhancing the efficacy of 5-ALAmediated PDT.