Synthesis of Paclitaxel Derivatives for Remote Loading into Liposomes and Improved Therapeutic Effect.

A series of novel paclitaxel derivatives modified by boronic acid according to the characteristics of the interaction between RB(OH)2 and different strapping agents of intraliposomal aqueous phase were designed and synthesized, which were then used to develop remote poorly water-soluble drugs loading into liposomes. Meanwhile, we screened nineteen paclitaxel boronic acid derivatives for their cytotoxic activities against three cancer cell lines (A549, HCT-116 and 4T1) and one normal cell line (LO2), and performed liposome formulation screening of active compounds. Among all the compounds, the liposome of 4d, with excellent drug-encapsulated efficiency (>95% for drug-to-lipid ratio of 0.1 w/w), was the most stable. Furthermore, the liposomes of compound 4d (8 mg/kg, 4 times) and higher dose of compound 4d (24 mg/kg, 4 times) showed better therapeutic effect than paclitaxel (8 mg/kg, 4 times) in the 4T1 tumor model in vivo, and the rates of tumor inhibition were 74.3%, 81.9% and 58.5%, respectively. This study provided a reasonable design strategy for the insoluble drugs to improve their drug loading into liposomes and anti-tumor effect in vivo.

Catalytic conversion of lignin pyrolysis model compound- guaiacol and its kinetic model including coke formation.

Lignin is the most difficult to be converted and most easy coking component in biomass catalytic pyrolysis to high-value liquid fuels and chemicals. Catalytic conversion of guaiacol as a lignin model compound was conducted in a fixed-bed reactor over ZSM-5 to investigate its conversion and coking behaviors. The effects of temperature, weight hourly space velocity (WHSV) and partial pressure on product distribution were studied. The results show the maximum aromatic carbon yield of 28.55% was obtained at temperature of 650 °C, WHSV of 8 h-1 and partial pressure of 2.38 kPa, while the coke carbon yield was 19.55%. The reaction pathway was speculated to be removing methoxy group to form phenols with further aromatization to form aromatics. The amount of coke increased with increasing reaction time. The surface area and acidity of catalysts declined as coke formed on the acid sites and blocked the pore channels, which led to the decrease of aromatic yields. Finally, a kinetic model of guaiacol catalytic conversion considering coke deposition was built based on the above reaction pathway to properly predict product distribution. The experimental and model predicting data agreed well. The correlation coefficient of all equations were all higher than 0.90.

Catalytic pyrolysis of black-liquor lignin by co-feeding with different plastics in a fluidized bed reactor.

Catalytic co-pyrolysis of black-liquor lignin and waste plastics (polyethylene, PE; polypropylene PP; polystyrene, PS) was conducted in a fluidized bed. The effects of temperature, plastic to lignin ratio, catalyst and plastic types on product distributions were studied. Both aromatic and olefin yields increased with increasing PE proportion. Petrochemical yield of co-pyrolysis of PE and lignin was LOSA-1 > spent FCC > Gamma-Al2O3 > sand. The petrochemical yield with LOSA-1 is 43.9% which is more than two times of that without catalyst. The feedstock for co-pyrolysis with lignin is polystyrene > polyethylene > polypropylene. Catalytic co-pyrolysis of black-liquor lignin with PS produced the maximum aromatic yield (55.3%), while co-pyrolysis with PE produced the maximum olefin yield (13%).

Catalytic conversion of biomass pyrolysis-derived compounds with chemical liquid deposition (CLD) modified ZSM-5.

Chemical liquid deposition (CLD) with KH550, TEOS and methyl silicone oil as the modifiers was used to modify ZSM-5 and deposit its external acid sites. The characteristics of modified catalysts were tested by catalytic conversion of biomass pyrolysis-derived compounds. The effects of different modifying conditions (deposited amount, temperature, and time) on the product yields and selectivities were investigated. The results show KH550 modified ZSM-5 (deposited amount of 4%, temperature of 20°C and time of 6h) produced the maximum yields of aromatics (24.5%) and olefins (16.5%), which are much higher than that obtained with original ZSM-5 catalyst (18.8% aromatics and 9.8% olefins). The coke yield decreased from 44.1% with original ZSM-5 to 26.7% with KH550 modified ZSM-5. The selectivities of low-molecule-weight hydrocarbons (ethylene and benzene) decreased, while that of higher molecule-weight hydrocarbons (propylene, butylene, toluene, and naphthalene) increased comparing with original ZSM-5.

Biomass fast pyrolysis in a fluidized bed reactor under N2, CO2, CO, CH4 and H2 atmospheres.

Biomass fast pyrolysis is one of the most promising technologies for biomass utilization. In order to increase its economic potential, pyrolysis gas is usually recycled to serve as carrier gas. In this study, biomass fast pyrolysis was carried out in a fluidized bed reactor using various main pyrolysis gas components, namely N(2), CO(2), CO, CH(4) and H(2), as carrier gases. The atmosphere effects on product yields and oil fraction compositions were investigated. Results show that CO atmosphere gave the lowest liquid yield (49.6%) compared to highest 58.7% obtained with CH(4). CO and H(2) atmospheres converted more oxygen into CO(2) and H(2)O, respectively. GC/MS analysis of the liquid products shows that CO and CO(2) atmospheres produced less methoxy-containing compounds and more monofunctional phenols. The higher heating value of the obtained bio-oil under N(2) atmosphere is only 17.8 MJ/kg, while that under CO and H(2) atmospheres increased to 23.7 and 24.4 MJ/kg, respectively.