蒸制断生后真空冷冻干燥对天麻质量的影响

目的:提高真空冷冻干燥天麻的天麻素含量。方法:采用蒸制后再真空冷冻干燥的方法对天麻进行干燥,考察天麻的外观及微观结构,测定天麻复水率、多糖和天麻素含量及不同干燥工艺下天麻粉末在模拟胃肠液中的溶出量与溶出率。结果:与鲜天麻直接真空冷冻干燥相比,天麻经蒸制后再真空冷冻干燥其外观和切面微观结构无显著变化。95℃蒸制4 min后再真空冷冻干燥,其天麻素含量和复水率分别为0.875%和502%,显著高于鲜天麻直接冷冻干燥(0.280%和362%)和120℃蒸制4 min后再真空冷冻干燥(0.775%和466%),但3个干燥工艺下天麻的多糖含量无显著差异。热风干燥天麻及真空冷冻干燥天麻粉末的红外指纹图谱谱峰位置相近,峰形相似,说明天麻成分无显著变化。不同工艺干燥天麻的天麻素在模拟胃液和肠液中的溶出率无显著差异。结论:天麻经95℃蒸制4 min后再进行真空冷冻干燥可在保持其外观和微观形态的条件下显著提高天麻素含量和复水率,天麻真空冷冻干燥生产中可对该工艺进行适当修正以推广应用。     

真空冷冻干燥法对林蛙油活性的稳定性研究

目的:研究真空冷冻干燥技术不同条件对林蛙油活性稳定性的影响。方法:以林蛙油为原料,真空冷冻干燥法对林蛙油进行干燥,采用相同真空度、不同温度和时间条件下进行对比试验,分别对其进行稳定性实验。结果:在不同的真空冷冻干燥条件下林蛙油活性稳定性不同,以酸价尤为显著。结论:对林蛙油真空冷冻干燥应采用快速冷冻,快速提供升华热的方法。     

蛋白质药品冷冻干燥过程中变性机理的研究进展

阐述了在药品冷冻干燥的过程中 ,蛋白质变性机理的研究现状 ,指出其中存在的问题 ,提出了研究思路和方法 ,以求优化冷冻干燥过程 ,提高冻干蛋白质的质量。     

不同干燥方法对醋制延胡索物性及成分溶出的影响

目的 考察不同干燥方法(烘干、晒干、真空干燥、真空冷冻干燥)对醋制延胡索物性以及成分溶出的影响，为醋制延胡索干燥方法筛选提供理论依据。方法 延胡索醋制后，分别进行烘干、晒干、真空干燥和真空冷冻干燥。比较复水率、折干率、硬度等物性参数，同时采用超高效液相色谱(UPLC)法测定醋制延胡索在不同时间段四氢非洲防己碱、原阿片碱、四氢黄连碱、非洲防己碱、延胡索乙素、盐酸小檗碱、盐酸巴马汀、去氢紫堇碱8种生物碱的溶出量，多指标结合化学计量学评价不同干燥方法对醋制延胡索饮片质量及成分溶出的影响。结果 醋延胡索烘干后表面收缩，形成相对致密的结构，成分溶出较慢。冷冻干燥后疏松多孔，质地较轻且含水量少，成分溶出快。结论 综合考虑成分含量、复水率、折干率、硬度等多指标，真空冷冻干燥醋制延胡索较其他干燥方法醋制延胡索有显著差异。真空冷冻干燥法处理的醋制延胡索饮片在加水回流提取20 min的成分溶出量明显高于另外3种干燥法处理的饮片，临床煎煮宜选用冷冻干燥法处理的醋制延胡索饮片。     

不同干燥方式对杜仲叶4种活性成分含量的影响

目的:考察不同干燥方式对杜仲叶中活性成分含量的影响,为建立杜仲叶在产地采收后的干燥加工方式提供参考。方法:取杜仲叶采用不同干燥方法[自然阴干72 h、自然晒干36 h、烘干(60℃6 h、80℃2 h、100℃1 h、120℃0.5 h)、微波真空冷冻干燥12 h、真空冷冻干燥12 h]对杜仲叶进行处理;采用高效液相色谱法同时测定样品中桃叶珊瑚苷、京尼平苷酸、绿原酸、京尼平苷的含量,并与未处理的鲜品进行比较。结果:2种冷冻干燥后的样品与鲜品中的4种成分含量接近,并高于其他干燥方式处理的样品。结论:干燥方法对杜仲叶有效成分具有较显著的影响,微波真空冷冻干燥和真空冷冻干燥较自然阴干、自然晒干、烘干更能保留杜仲鲜叶中的活性成分。     

热敏性药品的干燥

冷冻干燥过程中深度冷冻所得的冰晶,在后期还得利用20～30℃甚至更高的加热温度使之干燥,于是,产生为何不在20~30℃快速传热直接真空干燥药品湿滤饼,从而部分替代冷冻干燥机,达到节省投资和节能减排目的。     

冷冻干燥法制备明胶海绵止血剂

我们采用冷冻干燥法制备明胶海绵止血剂以供临床应用,效果尚好,方法如下:一、仪器与药品BS—711型多冷源真空干燥机JB90—D型增力搅拌卧式冰柜(武汉冷柜厂),真     

不同干燥方法对红花中有效成分的影响

目的比较不同干燥方法对红花提取物中有效成分羟基红花黄色素A的影响。方法采用高效液相色谱法测定红花各干燥产物中羟基红花黄色素A的含量,以其为指标,对不同干燥方法进行考察。结果采用真空干燥,喷雾干燥,冷冻干燥所得的产物中羟基红花黄色素A的含量分别为3.21%,8.55%,8.20%。结论相比真空干燥,喷雾干燥和冷冻干燥更适于红花提取物的干燥。     

浅谈冷冻干燥设备技术参数的确认

目的使冷冻干燥设备技术参数准确，运转性能可靠，确保干后的制品质量。方法选用适宜的仪器设备，对冷冻干燥设备的温度、真空测量中的一次元件(探测头)和二次元件(显示仪表)分别检测。同时对设备中主要的分立系统，如制冷系统、真空系统、栽冷剂的加热系统等的工作性能分别加以确认。结果上述各分立系统经确认合格后，冻干设备的综合技术指标达到要求，干燥后的制品质量可得到充分保障。     

不同干燥工艺的六味地黄提取物的粉体学性能评价

目的考察不同干燥工艺对六味地黄提取物物理性质与粉体学性质的影响。方法选用六味地黄提取物考察了真空干燥、喷雾干燥及冷冻干燥对六味地黄提取物物理性质与粉体学性质的差异。结果六味地黄喷雾干燥所得浸膏粉的黏性较小,所得粉粒较细小、圆整,且压缩度、抗张强度、吸湿速率及平衡吸湿量均比真空干燥的大。冷冻干燥所得浸膏粉的比表面积、孔容均比真空干燥的大。结论干燥方式及原理的不同导致了干燥产物物理性质与粉体学性质的差异,应根据不同制备的需求选择不同的制备工艺。     

Lyophilization and development of solid protein pharmaceuticals

Developing recombinant protein pharmaceuticals has proved to be very challenging because of both the complexity of protein production and purification, and the limited physical and chemical stability of proteins. To overcome the instability barrier, proteins often have to be made into solid forms to achieve an acceptable shelf life as pharmaceutical products. The most commonly used method for preparing solid protein pharmaceuticals is lyophilization (freeze-drying). Unfortunately, the lyophilization process generates both freezing and drying stresses, which can denature proteins to various degrees. Even after successful lyophilization with a protein stabilizer(s), proteins in solid state may still have limited long-term storage stability. In the past two decades, numerous studies have been conducted in the area of protein lyophilization technology, and instability/stabilization during lyophilization and long-term storage. Many critical issues have been identified. To have an up-to-date perspective of the lyophilization process and more importantly, its application in formulating solid protein pharmaceuticals, this article reviews the recent investigations and achievements in these exciting areas, especially in the past 10 years. Four interrelated topics are discussed: lyophilization and its denaturation stresses, cryo- and lyo-protection of proteins by excipients, design of a robust lyophilization cycle, and with emphasis, instability, stabilization, and formulation of solid protein pharmaceuticals.     

Roles of cryo/thermal strength for redispersibility of drug nanocrystals: a representative study with andrographolide

Due to limited understanding about the effect of cryo/thermal strength from drying process on the redispersibility of drug nanocrystals, the impact of the different type and concentration of stabilizers and matrix formers on the redispersibility of nanocrystals were systematically investigated. Andro nanosuspensions were transformed into Andro nanocrystals (Andro-NC) via different drying process. The results demonstrated that the redispersibility of Andro-NC at the aggressive cryo-strength (meant higher freezing rate) was more excellent than those at conservative and moderate condition. Compared to the thermal stress from drying, the employed amount and type of stabilizers more dramatically affected the redispersibility of Andro-NCP during lyophilization. The HPMC-sucrose and HPMC-sorbitol system achieved excellent performance that protected Andro-NC from crystal growth during lyophilization. During spray-drying, the impacts of types and amounts of stabilizers on the redispersibility of Andro-NCP were more significant compared to those induced by the thermal stress conditions. The polymers HPMC, PVPK30 and MCCS with high Tg played an outstanding role in preventing the Andro-NCP from breakage during spray-drying, due to the firmly steric barrier effect of polymeric stabilizers. It is concluded that Andro-NCP is subjected to agglomeration or crystal growth due to cryo/thermal stresses during drying. The polymeric stabilizers are more effective to protect Andro-NCP from the cryo/thermal damage during solidification process, which behaved strong surface adsorption and high glass transition property at different solidification stress.     

Solidification drug nanosuspensions into nanocrystals by freeze-drying: a case study with ursodeoxycholic acid

To elucidate the effect of solidification processes on the redispersibility of drug nanocrystals (NC) during freeze-drying, ursodeoxycholic acid (UDCA) nanosuspensions were transformed into UDCA-NC via different solidification process included freezing and lyophilization. The effect of different concentrations of stabilizers and cryoprotectants on redispersibility of UDCA-NC was investigated, respectively. The results showed that the redispersibility of UDCA-NC was RDI_?20?°C?<?RDI_?80?°C?<?RDI_?196?°C during freezing, which indicated the redispersibility of UDCA-NC at the conventional temperature was better more than those at moderate and rigorous condition. Compared to the drying strengthen, the employed amount and type of stabilizers more dramatically affected the redispersibility of UDCA-NC during lyophilization. The hydroxypropylmethylcellulose and PVPK30 were effective to protect UDCA-NC from damage during lyophilization, which could homogeneously adsorb into the surface of NC to prevent from agglomerates. The sucrose and glucose achieved excellent performance that protected UDCA-NC from crystal growth during lyophilization, respectively. It was concluded that UDCA-NC was subjected to agglomeration during solidification transformation, and the degree of agglomeration suffered varied with the type and the amounts of stabilizers used, as well as different solidification conditions. The PVPK30-sucrose system was more effective to protect UDCA-NC from the damage during solidification process.     

Protein Quantity on the Air–Solid Interface Determines Degradation Rates of Human Growth Hormone in Lyophilized Samples

Recombinant human growth hormone (rhGH) was lyophilized with various glass-forming stabilizers, employing cycles that incorporated various freezing and annealing procedures to manipulate glass formation kinetics, associated relaxation processes, and glass-specific surface areas (SSAs). The secondary structure in the cake was monitored by infrared and in reconstituted samples by circular dichroism. The rhGH concentrations on the surface of lyophilized powders were determined from electron spectroscopy for chemical analysis. Glass transition temperature (T_g), SSAs, and water contents were determined immediately after lyophilization. Lyophilized samples were incubated at 323 K for 16 weeks, and the resulting extents of rhGH aggregation, oxidation, and deamidation were determined after rehydration. Water contents and T_g were independent of lyophilization process parameters. Compared with samples lyophilized after rapid freezing, rhGH in samples that had been annealed in frozen solids prior to drying, or annealed in glassy solids after secondary drying retained more native-like protein secondary structure, had a smaller fraction of the protein on the surface of the cake, and exhibited lower levels of degradation during incubation. A simple kinetic model suggested that the differences in the extent of rhGH degradation during storage in the dried state between different formulations and processing methods could largely be ascribed to the associated levels of rhGH at the solid–air interface after lyophilization. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.     

Impact of critical process and formulation parameters affecting in-process stability of lactate dehydrogenase during the secondary drying stage of lyophilization: a mini freeze dryer study

The stresses during the secondary-drying stage of lyophilization were investigated using a controlled humidity mini-freeze-dryer [Luthra S, Obert J-P, Kalonia DS, Pikal MJ. 2007. Investigation of drying stresses on proteins during lyophilization: Differentiation between primary and secondary-drying stresses on lactate dehydrogenase using a humidity controlled mini freeze-dryer. J Pharm Sci 96: 61-70.]. Lactate dehydrogenase (LDH), was formulated in: (1) Tween 80, (2) citrate buffer, and (3) both Tween 80 and citrate buffer. Protein activity recovery was measured as a function of relative humidity (RH), product temperature, and drying duration. Studies were also conducted with different concentrations of sucrose, sorbitol, and poly (vinyl pyrrolidone) (PVP). LDH stability was affected to a small extent by RH and significantly by drying temperature and duration. Complete stabilization of LDH was observed when lyophilized with sucrose and PVP but only a partial stabilization was observed with sorbitol. The mini-freeze-dryer enabled studying the process parameters independently, unlike a conventional study where these effects are generally convoluted. The results suggest that the stability of the protein is a function of the dynamics of the system during lyophilization. The origin of the stabilization effect of sucrose, which could, in principle, be attributed both to direct interaction with the protein or vitrification of the protein was elucidated using lyoprotectants that can either hydrogen bond well with the protein (sorbitol) or form a good glass (PVP). It appears both effects are required for complete stabilization of the protein.     

In situ monitoring of proteins during lyophilization using micro-Raman spectroscopy: a description of structural changes induced by dehydration

Raman investigations were carried out in situ in real time during the lyophilization of three proteins (β-lactoglobulin, bovine serum albumin, and chymotrypsinogen) characterized by different structural properties. Structural changes in the proteins were only and systematically detected after the primary drying step of the lyophilization, through a frequency shift and a general broadening of amide I and III bands. These spectral changes have been interpreted in terms of local disordering related to the distortion of the structural elements induced by ice desorption. Structural changes of the secondary structure were found almost reversible upon rehydration, whereas changes in the solvent accessibility to protein residues are detected and related to the alteration of the tertiary and/or quaternary structures. The influence of the lyophilization parameters, corresponding to different stress conditions, on the degree of protein denaturation has been analyzed.     

Current Approaches of Preservation of Cells During (freeze-) Drying

The widespread application of therapeutic cells requires a successful stabilization of cells for the duration of transport and storage. Cryopreservation is currently considered the gold standard for the storage of active cells; however, (freeze-) drying cells could enable higher shelf life stability at ambient temperatures and facilitate easier transport and storage.During (freeze-) drying, freezing, (primary and secondary) drying and also the reconstitution step pose the risk of potential cell damage. To prevent these damaging processes, a wide range of protecting excipients has emerged, which can be classified, according to their chemical affiliation, into sugars, macromolecules, polyols, antioxidants and chelating agents. As many excipients cannot easily permeate the cell membrane, researchers have established various techniques to introduce especially trehalose intracellularly, prior to drying.This review aims to summarize the main damaging mechanisms during (freeze-) drying and to introduce the most common excipients with further details on their stabilizing properties and process approaches for the intracellular loading of excipients. Additionally, we would like to briefly explain recently discovered advantages of drying microorganisms, sperm, platelets, red blood cells, and eukaryotic cells, paying particular attention to the drying technique and residual moisture content.     

In-Situ Molecular Vapor Composition Measurements During Lyophilization

Purpose

Monitoring process conditions during lyophilization is essential to ensuring product quality for lyophilized pharmaceutical products. Residual gas analysis has been applied previously in lyophilization applications for leak detection, determination of endpoint in primary and secondary drying, monitoring sterilization processes, and measuring complex solvents. The purpose of this study is to investigate the temporal evolution of the process gas for various formulations during lyophilization to better understand the relative extraction rates of various molecular compounds over the course of primary drying.

Methods

In this study, residual gas analysis is used to monitor molecular composition of gases in the product chamber during lyophilization of aqueous formulations typical for pharmaceuticals. Residual gas analysis is also used in the determination of the primary drying endpoint and compared to the results obtained using the comparative pressure measurement technique.

Results

The dynamics of solvent vapors, those species dissolved therein, and the ballast gas (the gas supplied to maintain a set-point pressure in the product chamber) are observed throughout the course of lyophilization. In addition to water vapor and nitrogen, the two most abundant gases for all considered aqueous formulations are oxygen and carbon dioxide. In particular, it is observed that the relative concentrations of carbon dioxide and oxygen vary depending on the formulation, an observation which stems from the varying solubility of these species. This result has implications on product shelf life and stability during the lyophilization process.

Conclusions

Chamber process gas composition during lyophilization is quantified for several representative formulations using residual gas analysis. The advantages of the technique lie in its ability to measure the relative concentration of various species during the lyophilization process. This feature gives residual gas analysis utility in a host of applications from endpoint determination to quality assurance. In contrast to other methods, residual gas analysis is able to determine oxygen and water vapor content in the process gas. These compounds have been shown to directly influence product shelf life. With these results, residual gas analysis technique presents a potential new method for real-time lyophilization process control and improved understanding of formulation and processing effects for lyophilized pharmaceutical products.

     

Effect of Product Temperature During Primary Drying on the Long-Term Stability of Lyophilized Proteins

Our objective was to investigate the effect of performing primary drying at product temperatures below and above Tg′ (glass transition temperature of the freeze-concentrated phase) on the long-term stability of lyophilized proteins. Two protective media differing in the nature of the bulking agent used (amorphous or crystalline) were selected. Several lyophilization cycles were performed by using various combinations of shelf temperature and chamber pressure to obtain different values of product temperature during primary drying. The antigenic activity of the proteins was measured after lyophilization and after 6 months of storage at 4°C and 25°C. After 6 months of storage and regardless of the protective medium, the losses of antigenic activity of both toxins increased from 0% when primary drying was performed at a product temperature lower than Tg′ and to 25% when the product temperature was higher than Tg′. The use of partially crystalline systems makes it possible to withstand high primary drying temperatures (above Tg′). However, the shelf life of lyophilized proteins may be decreased when the amorphous phase including the protein and the stabilizing molecule changes to the viscous state.     

Effect of product temperature during primary drying on the long-term stability of lyophilized proteins.

Our objective was to investigate the effect of performing primary drying at product temperatures below and above Tg' (glass transition temperature of the freeze-concentrated phase) on the long-term stability of lyophilized proteins. Two protective media differing in the nature of the bulking agent used (amorphous or crystalline) were selected. Several lyophilization cycles were performed by using various combinations of shelf temperature and chamber pressure to obtain different values of product temperature during primary drying. The antigenic activity of the proteins was measured after lyophilization and after 6 months of storage at 4 degrees C and 25 degrees C. After 6 months of storage and regardless of the protective medium, the losses of antigenic activity of both toxins increased from 0% when primary drying was performed at a product temperature lower than Tg' and to 25% when the product temperature was higher than Tg'. The use of partially crystalline systems makes it possible to withstand high primary drying temperatures (above Tg'). However, the shelf life of lyophilized proteins may be decreased when the amorphous phase including the protein and the stabilizing molecule changes to the viscous state.