Supercritical fluids in medical radioisotope processing and chemistry,Part II: Applications – real and demonstrated

In Part I of this review series, an overview was presented on what the basic properties of supercritical fluids are and how they can, and are being used in many of today's industries as solvents for extraction, chromatography and reaction. A good part of this overview detailed the kinds of equipment needed, and techniques on how to use them for optimal performance. Part II of this series will delve into specific applications of supercritical fluid technology as it relates to aspects of medical isotope processing. The reader will note that very few applications of this technology to Nuclear Medicine have been published. Many potential applications cited within the context of this review derive from preliminary studies carried out in the author's laboratory. These examples are presented to spark interest in future developments of this nature. Copyright © 2003 John Wiley & Sons, Ltd.     

Polymeric Microspheres Prepared by Spraying into Compressed Carbon Dioxide

Purpose. The objective was to prepare polymeric microparticles by atomizing organic polymer solutions into a spray chamber containing compressed CO₂ (PCA-process) and to study the influence of various process parameters on their morphological characteristics. Methods. The swelling of various pharmaceutically acceptable polymers [ethyl cellulose, poly(methyl methacrylate), poly(-caprolactone), poly(dl-lactide), poly(l-lactide) and poly(dl-lactide-glycolide) copolymers] in CO₂ was investigated in order to find polymers which did not agglomerate during the spraying process. Poly(l-lactide) (L-PLA) microparticles were prepared by spraying the organic polymer solution into CO₂ in a specially designed spraying apparatus. The effect of various process (pressure and temperature of the CO₂ phase, flow rate) and formulation (polymer concentration) variables on the morphology and particle size of L-PLA-microparticles was investigated. Results. Polymers with low glass transition temperatures agglomerated even at low temperatures. The formation of microparticles was favored at moderate temperatures, low polymer concentrations, high pressures and high flow rates of CO₂. High polymer concentrations and low flow rates resulted in the formation of polymeric fibers. Colloidal L-PLA particles could also be prepared with this technique in a surfactant-free environment. Initial studies on the microencapsulation of drugs resulted in low encapsulation efficiencies. Conclusions. The PCA method is a promising technique for the preparation of drug-containing microparticles. Potential advantages of this method include the flexibility of preparing microparticles of different size and morphology, the elimination of surfactants, the minimization of residual organic solvents, low to moderate processing temperatures and the potential for scale-up.     

尿毒清片提取工艺实验研究

目的：对尿毒清薄膜片的提取工艺进行研究。方法：以含量测定和药效学的方法比较了大黄三种工艺的提取效果；采用正交设计方法优选尿毒清复方超临界CO2萃取的工艺条件。结果：大黄用超临界CO2萃取工艺，可提高有效成分的提取率及保证疗效，超临界CO2萃取最佳工艺条件为：A2B2C2D1，提取工艺路线设计合理，对大生产有指导意义。     

超临界CO_2流体萃取榧树假种皮挥发油化学成分的研究

目的:研究超临界CO_2流体萃取榧树假种皮挥发油并分析挥发油组成。方法:采用超临界CO_2流体萃取技术提取其精油部分,经二级解析分离出精油Ⅰ和Ⅱ,并用气相色谱-质谱-计算机联用技术进行分离和鉴定。结果:挥发油的最佳萃取条件为压力32mPa、温度40℃、时间1h。榧树假种皮挥发油含量为5.83％,挥发油由柠檬烯等48个化学成分组成。结论:超临界CO_2流体萃取榧树假种皮挥发油具有提取时间短、提取完全等优点。     

黄芪中重金属超临界CO_2净化技术研究

目的利用超临界CO2 萃取技术净化黄芪中重金属。方法a 以二乙基二硫代氨基甲酸钠(DDTC)为金属络合剂 ,用超临界流体萃取技术净化药材中的重金属 ,并对萃取方案进行最优化。b 选择不同的混酸消化液完全消解药材后 ,以空气 乙炔火焰AAS法和氢化物发生AAS法分别测定其中的铅 (Pb)、镉 (Cd) ,以及砷 (As)、汞 (Hg)。c 采用UCTRONVX -ODS(2 5 0mm×4 6mm ,5 μm)色谱柱 ,以乙腈 水 (V∶V =30∶70 )为流动相 ,检测波长为 2 0 3nm ,卡马西平为内标 ,测定黄芪中黄芪甲苷的含量。结果与结论a 确定了药材中重金属的最佳萃取条件。在最佳萃取条件下 ,重金属净化率达到 85 %以上 ;同时 ,中药材中的有效成分损失低于 5 %。b 建立了药材中金属元素和有效成分的含量测定方法 ,为正确评价中药材的质量奠定了基础 ,可用于正确评价净化前后药材的质量变化     

超临界流体萃取技术在中药生物碱提取中的应用

目的对超临界二氧化碳流体萃取中药中生物碱的应用进行综述。方法通过与传统的生物碱提取方法相比较 ,总结了超临界二氧化碳流体萃取生物碱的工艺特点及应用。结果与结论超临界流体萃取技术可以有效地提取中药中的生物碱 ,并具有产率高、方便快捷、后处理简单、无污染等优点     

聚碳酸酯在超临界乙醇中的降解

利用高压间歇反应器研究了聚碳酸酯(PC)在215~286°C、3.1~8.2 M Pa条件下乙醇溶液中的降解行为。通过气相色谱/质谱(GC/M S)和气相色谱(GC)对液相产物进行了定性和定量分析,同时分别通过红外(IR)和气相色谱对固相产物和气相产物进行了定性分析,在此基础上,提出了PC在超临界乙醇中的降解机理和降解反应模型,并进行了动力学研究。结果表明:PC在乙醇溶液中的降解可分为3个区域:超临界区、非超临界区和中间过渡区。在超临界区中,PC可实现完全降解,其主要单体双酚A(BPA)和碳酸二乙酯(DEC)的收率分别为92.26%和88.92%。在超临界区PC的降解活化能为89.73 kJ/m o l;在非超临界区,PC的降解活化能为21.02 kJ/m o l。     

淫羊藿中重金属超临界CO2流体净化技术研究

目的利用超临界CO2萃取技术(SFE)净化淫羊藿中重金属.方法①以二乙基二硫代氨基甲酸钠(DDC-Na)为金属络合剂,用超临界流体萃取技术净化药材中的重金属,并对萃取方案进行最优化.②选择不同的混合酸消化液完全消解药材后,以空气-乙炔火焰原子吸收法(AAS)和氢化物发生AAS法分别测定其中的铅(Pb)、镉(Cd)以及砷(As)、汞(Hg).③采用Kromasil C18(250 mm×4.6 mm,5 μm )色谱柱,以甲醇-水(60∶40)为流动相,检测波长为270 nm,测定淫羊藿中淫羊藿苷的含量.结果在最佳萃取条件下,重金属净化率达到90%以上,中药材有效成分的损失＜5%.结论确定了药材中重金属的最佳萃取条件.     

超临界CO2萃取鹿茸中的性激素研究

目的：研究超临界CO₂萃取技术提取鹿茸中性激素。方法：超临界CO₂萃取鹿茸中的性激素并采用放射免疫法分析其含量,利用GC-MS,TLC和HPLC分析了萃取物中其他成分。结果：以85%乙醇为夹带剂,夹带剂∶原料=1(mL·g^-1),萃取压力30 MPa,萃取温度65 ℃,总提取率为1.56%,雌二醇和孕酮的质量分数分别为3.07,776.18 ng·g^-1。结论：采用超临界CO2萃取技术提取鹿茸中的性激素是可行的。     

Optimization of Supercritical Fluid Extraction and Rapid Resolution LC-MS/ESI Identification of Chromones from Saposhnikoviae Radix through Orthogonal Array Design

Objective To establish a rapid and effective supercritical fluid extraction(SFE) and rapid resolution liquid chromatography method coupled with diode-array detector(RRLC-DAD) to quantify the chromones in a species. Methods The effects of four parameters including ethanol concentration(50%-90%), pressure(25-45 MPa), temperature(40-60 ℃), and time(30-90 min) on the chromones yields, namely prim-O-glucosylcimifugin, cimifugin, 5-O-methylvisammioside, and sec-O-glucosylhamaudol, were investigated using SFE system with orthogonal array design(OAD). Furthermore, the extracts were analyzed using rapid resolution liquid chromatography coupled with diode-array detector(RRLC-DAD) system to confirm the results. Results Under the optimized conditions, i.e., 35 MPa of pressure, 60 ℃ of temperature, 70% ethanol, and 60 min of time, the yields of prim-O-glucosylcimifugin, cimifugin, 5-O-methylvisammioside, sec-O-glucosylhamaudol, and total chromones were 3.514, 0.132, 6.242, 0.342, and 10.231 mg/g, respectively. In comparison with ultrasonic assisted extraction(UAE), SFE was able to yield a 20.7% increase in the total chromones from Saposhnikoviae Radix. Conclusion SFE is an alternative and promising method to extract chromones from this species, and the established RRLC-DAD method could serve as a rapid and effective method for the identification of chromones from Saposhnikoviae Radix.