Spray freeze drying for dry powder inhalation of nanoparticles

Formulating nanoparticles for delivery to the deep lung is complex and many techniques fail in terms of nanoparticle stability. Spray freeze drying (SFD) is suggested here for the production of inhalable nanocomposite microcarriers (NCM). Different nanostructures were prepared and characterized including polymeric and lipid nanoparticles. Nanoparticle suspensions were co-sprayed with a suitable cryoprotectant into a cooled, stainless steel spray tower, followed by freeze drying to form a dry powder while equivalent compositions were spray dried (SD) as controls. SFD-NCM possess larger specific surface areas (67–77 m²/g) and lower densities (0.02 g/cm³) than their corresponding SD-NCM. With the exception of NCM of lipid based nanocarriers, SFD produced NCM with a mass median aerodynamic diameter (MMAD) of 3.0 ± 0.5 μm and fine particle fraction (FPF ⩽ 5.2 μm) of 45 ± 1.6% with aerodynamic performances similar to SD-NCM. However, SFD was superior to SD in terms of maintaining the particle size of all the investigated polymeric and lipid nanocarriers following reconstitution (S_f/S_i ratio for SFD ≈ 1 versus >1.5 for SD). The SFD into cooled air proved to be an efficient technique to prepare NCM for pulmonary delivery while maintaining the stability of the nanoparticles.     

Temperature Measurement by Sublimation Rate as a Process Analytical Technology Tool in Lyophilization

Product temperature (T_b) and drying time constitute critical material attributes and process parameters in the lyophilization process and especially during the primary drying stage. In the study, we performed a temperature measurement by the sublimation rate (TMbySR) to monitor the T_b value and determine the end point of primary drying. First, the water vapor transfer resistance coefficient through the main pipe from the chamber to the condenser (C_r) was estimated via the water sublimation test. The use of C_r value made it possible to obtain the time course of T_b from the measurement of pressure at the drying chamber and at the condenser. Second, a Flomoxef sodium bulk solution was lyophilized by using the TMbySR system. The outcome was satisfactory when compared with that obtained via conventional sensors. The same was applicable for the determination of the end point of primary drying. A laboratory-scale application of the TMbySR system was evidenced via the experiment using 220-, 440-, and 660-vial scales of lyophilization. The outcome was not dependent on the loading amount. Thus, the results confirmed that the TMbySR system is a promising tool in laboratory scale.     

The role of particle physico-chemical properties in pulmonary drug delivery for tuberculosis therapy

Abstract

There is increasing interest in the use of inhaled aerosol drug therapy for the treatment of tuberculosis (TB). A number of methods of preparation of particles have been employed including spray drying, solvent evaporation, emulsion and phospholipid methods to create microparticles, macroaggregated nanoparticles, solid lipid nanoparticles and liposomes. Each of these methods involves the use of different proportions of additives to aid in the particle formation or to achieve important physico-chemical properties such as ease of dispersion. While these approaches all have merit their practical value is limited by constraints on dose and means of delivery as an aerosol in order to achieve a therapeutic effect. A review of a number of approaches is presented and placed in the context of the need for effective aerosol delivery systems for the treatment of TB as a guide to selection of appropriate excipients, processes and delivery strategies to support product development activities.     

Progress involving new techniques for liposome preparation

The article presents a review of new techniques being used for the preparation of liposomes. A total of 28 publications were examined. In addition to the theories, characteristics and problems associated with traditional methods, the advantages and drawbacks of the latest techniques were reviewed. In the light of developments in many relevant areas, a variety of new techniques are being used for liposome preparation and each of these new technique has particular advantages over conventional preparation methods. However, there are still some problems associated with these new techniques that could hinder their applications and further improvements are needed. Generally speaking, due to the introduction of these latest techniques, liposome preparation is now an improved procedure. These applications promote not only advances in liposome research but also the methods for their production on an industrial scale.     

黄芪药材不同干燥方式对其饮片的提取动力学影响

目的 考察在自然干燥、热风干燥、减压真空干燥方式下的黄芪药材经炮制成饮片后，药效成分的提取动力学。方法 以传统水煎煮法对黄芪饮片进行提取，建立提取动力学模型，比较黄芪药材经自然干燥、热风干燥、减压真空干燥3种初加工方式对饮片中4个评价指标（浸出物、黄芪多糖、毛蕊异黄酮葡萄糖苷、黄芪甲苷）提取效率差异。结果 3种干燥方式导致黄芪药材切面品相不一，提取动力学均与一级动力学模型拟合效果最佳，其中减压干燥动力学拟合方程斜率最大，提取效率最高。结论 减压干燥方式4个评价指标的药材-饮片转移率高，干燥、提取速率快，可作为传统干燥方式的替代干燥方式。不同干燥方式不仅对药材品相有影响，同时对药材制成饮片及后续饮片制成制剂过程中评价指标的提取效率也有影响，说明干燥等药材初加工是药材-饮片-制剂品质传递过程中的重要环节，应引起足够的关注。     

Investigation of the effects of process variables on derived properties of spray dried solid-dispersions using polymer based response surface model and ensemble artificial neural network models

The objective of this study was to use different statistical tools to understand and optimize the spray drying process to prepare solid dispersions. In this study we investigated the relationship between input variables (inlet temperature, feed concentration, flow rate, solvent and atomization parameters) and quality attributes (yield, outlet temperature and mean particle size) of spray dried solid dispersions (SSDs) using response surface model and ensemble artificial neural network. The Box Behnken design was developed to investigate the effect of various input variables on quality attributes of final products. Moreover, Pearson correlation analysis, self organizing map, contour plots and response surface plot were used to illustrate the relationship between input variables and quality attributes. The influence of different physicochemical properties of solvent on the quality attributes of spray dried products was also investigated. Final validation of prepared models was done using binary SSDs of six model drugs with PVP. Results demonstrated the effectiveness of proposed PVP based model which can help scientists to gain detailed understanding of spray drying process of solid dispersion using minimal resources and time during early formulation development stage. It will also help them to ensure consistent quality of SSDs using broad range of input variables.     

Drug/polymer nanoparticles prepared using unique spray nozzles and recent progress of inhaled formulation

Inhaled formulations are promising for pulmonary and systemic non-pulmonary diseases. Functional engineered particles including drugs and drug-loaded nanocarriers have been anticipated because they can improve drug delivery efficacy against target sites in the lungs or blood. In this review, unique spray nozzles (e.g., four-fluid spray nozzle and two-solution mixing type nozzle) for the preparation of nanocomposite particles which mean microparticles containing drug nanoparticles are described. These nozzles can produce nanocomposite particles in one-step and their spray drying system is suitable for scaling-up. Nanocomposite particles are useful in improving drug absorption and delivery efficacy against alveolar macrophages. In addition, recent studies on several pulmonary diseases (tuberculosis, lung cancer, cystic fibrosis, pneumonia, vaccine and others) and related inhaled formulations were also reviewed.     

Development of a spray-drying method for the formulation of respirable microparticles containing ofloxacin–palladium complex

The purpose of this study was to produce low-releasing spray-dried polymeric microparticles (MP) useful to target alveolar macrophages in tuberculosis (TB) inhalation therapy.     

一年二十四节气中新鲜与阴干黄芩根黄酮类成分含量对比及其相关性

目的：研究山东临朐栽培黄芩在一年二十四节气中,新鲜和阴干黄芩根黄芩苷等四种黄酮类成分的含量对比及其相关性。方法连续一年（2013—2014年）按照二十四节气采收黄芩根,用高效液相色谱法检测新鲜和阴干样品中四种黄酮类成分的含量。结果各节气样品阴干后黄芩苷及总苷、总黄酮含量较新鲜显著增加,而黄芩素和总苷元则显著下降;汉黄芩苷和汉黄芩素变化不明显。此外,阴干根中黄酮苷类成分的含量增加与新鲜根中原有成分的含量无相关性。结论一年各节气黄芩根的黄酮苷类成分主要是在采后干燥胁迫过程中产生的。