Studies On Ferulic Acid Liposome For Injection (Freeze Drying)

Ferulic acid （FA） is the primarily active ingredient of many Chinese traditional Medicines （TCMs） which were used to treat neurovascular and cardiovascular diseases. Many investigations suggest that FA can exhibit significant pharmacological effects including antioxidant, radical scavenging, anti-apoptotic, anti-inflammatory, anti-platelet aggregation and anti-artherosclerosis. It can increase the antioxidant effects and the protect effect to cerebral ischemia to load FA into liposome.The linearity concentration is from 0.31μg/mL to 15.5μg/mL for HPLC. It is more stable for FA in weak acid condition. It is the most stable for FA in stilled water and alcohol. It is better stable under 4℃to store FA. The solubility of FA increased with the rising of pH value, and in absolute alcohol the solubility was the best. The pKa of FA is 4.99 and 8.05, respectively.The linearity concentration is from 1.70μg/mL to 8.5μg/mL for ultraviolet spectrophotometry. Ultrafiltration was used to separate free drug and liposome. The prescription and technology condition were studied. The final prescription is lipid （S-100: E-80, 6:1）: cholest 5:1; drug : lipid 1:20. The pressure was increasing gradually up to 800 bar, circulation 6 times, flow rate of 35Hz. 74.5% encapsulation efficiency was obtained. The macroporous adsorptive resins can be used to set up acetic acid gradient to substitute exclusion-chromatograpliy method because it is more economic and easier for manipulation and industrialization. The condition for loading FA into liposome was under ambient temperature and for 10min.The prescription and technology of freeze-drying were studied with index of encapsulation efficiency, appearance, particle sizing and reconstruction. The co-fusing-point of FA liposome is -10.6℃. Mycose and sugar was used to act as cryoprotectant and the ratio of mycose-lipid-sugar was 1:2:4 with internal adding method and 15mg/mL lipid concentration. The parameters of freeze-drying technology pre-freeze were at -40℃for 3h; the first dry was at -25℃for 10h; the second dry is at 20℃for 3h. There was no significantly change on encapsulation efficiency and particle sizing under ambient temperature during six months.The physico-chemical properties of freeze drying product （FD-FAL） were valued with mean particle size 139.1nm, zeta potential +8.69 and 80% of total drug was released from liposoms within 7h.The Pharmacokinetics parameters of FD-FAL and FA solution were determined with HPLC. T_1/2, AUC, and Cl of FD-FAL was 0.47h, 990.20μg·min/ml and 72.71 ml/min, respectively. T_1/2, AUC, and Cl of FA solution was 0.29h, 682.66μg·min/ml and 105.48ml/min, respectively.The rat model of cerebral ischemia was set up to value the pharmacodynamic action of FD-FAL. FD-FAL can significantly increase SOD activity and the score of foot-fault test; decrease MDA content, the ratio of SOD-MDA and ischemia volume. The pharmacodynamic effect was greatly better than Danshen injection and FA solution.The objective of increasing the pharmacodynamic effect of FA in this study was achieved by loading FA into liposome.