Disposition kinetics of ketotifen from liposomal dry powder for inhalation in rat lung

1. The aim of the present study was to understand the benefit of liposomal dry powder for inhalation (LDPI) of ketotifen fumarate (KF) over plain drug dry powder for inhalation as a pulmonary targetted drug-delivery system. 2. The KF liposomes, composed of egg phosphatidyl choline and cholesterol, were prepared by the lipid film hydration technique. The liposomal dispersion was freeze dried and formulated to a dry powder for inhalation. Values of 89.0-65.3% drug entrapment of freeze-dried liposomes were estimated in prepared batches. 3. Rehydrated KF liposomes formed by the hydration of LDPI or the plain KF solution was delivered to rat lungs by intratracheal instillation. Simultaneous monitoring of drug levels in the bronchoalveolar lavage and lung tissue enabled assessment of pulmonary drug disposition. 4. Cumulative drug levels in lung tissue after intratracheal administration revealed that with liposomes targetting factors were between 1.36 and 1.54. The maximal drug concentration in lung homogenate for LDPI was 42.0 micro g compared with 73.6 micro g for plain drug solution. 5. Similarly, the time to reach maximum drug concentration in the lung homogenate for liposomal dry powder was 9-12 h compared with 3 h for plain drug. 6. Hence, the use of LDPI of KF was found to provide desired drug levels in the lung for a long time and thereby increased pulmonary targetting 7. This is expected to enhance the therapeutic index of the drug and probably reduce the dose administered and the cost of therapy.     

鲑鱼降钙素肺部干粉吸入剂的制备及含量影响因素的考察

目的喷雾干燥法制备鲑鱼降钙素(salmon calcitonin,sCT)肺部干粉吸入剂;考察溶液pH值、喷干温度和处方中泊洛沙姆(F68)的用量对鲑鱼降钙素含量的影响。方法分别制备不同pH值和不同F68用量的鲑鱼降钙素溶液,在不同温度下喷雾干燥制备鲑鱼降钙素干粉吸入剂粉末,用高效液相色谱仪对所制备的粉末进行含量测定。采用TSI装置测定粉末沉积率,用LS320激光粒度测定仪测定粒径大小,用扫描电子显微镜观察粉末的表面形态。结果制备的鲑鱼降钙素吸入粉末的平均粒径为2.1μm,沉积率在45.42%左右。在pH小于3.3的冰醋酸溶液中,F68的用量超过固型物总量的1%时,喷干温度低于120℃时,鲑鱼降钙素喷雾干燥后的含量均在80%以上。结论在较低的pH环境中,选用适量的蛋白保护剂F68,采用较低的喷干温度,均可有效的降低喷干过程中鲑鱼降钙素的变性几率。     

Single-use disposable dry powder inhalers for pulmonary drug delivery

Importance of the field: The understanding of pulmonary drug delivery and thus its utilization for medical purposes has remarkably advanced over the last decades. It has been recognized that this route of administration offers many advantages and several drug delivery systems have been developed accordingly. Thereby, single-use disposable dry powder inhalers may be considered an economically and therapeutically valuable option for both local and systemic administration of drugs to treat a variety of different disease states.

Areas covered in this review/What the reader will gain: This review highlights the required characteristics and potential applications of single-use disposable dry powder inhalers considering advantages as well as limitations of these drug delivery devices. Until now, such drug delivery systems have not become widely accepted. Several devices are available or under development and a few products have reached or completed the clinical phase, but none of them have received market authorization as yet.

Take home message: Recent advances in formulation and device design, however, can be considered encouraging and should eventually lead to a wider establishment of single-use disposable dry powder inhalers in pulmonary drug delivery.     

Formulation and Characterization of Lipid-Coated Tobramycin Particles for Dry Powder Inhalation

Purpose This study was conducted to develop and evaluate the physicochemical and aerodynamic characteristics of lipid-coated dry powder formulations presenting particularly high lung deposition. Methods Lipid-coated particles were prepared by spray-drying suspensions with different concentrations of tobramycin and lipids. The solid-state properties of the formulations, including particle size and morphology, were assessed by scanning electron microscopy and laser diffraction. Aerosol performance was studied by dispersing the powders into a Multistage Liquid Impinger and determining drug deposition by high-performance liquid chromatography. Results Particle size distributions of the formulations were unimodal, narrow with more than 90% of the particles having a diameter of less than 2.8 μm. All powder formulations exhibited mass median diameters of less than 1.3 and 3.2 μm, as determined by two different laser diffraction methods, the Malvern's Mastersizer? and Spraytec?, respectively. The fine particle fraction varied within a range of 50.5 and 68.3%. Conclusions Lipid coating of tobramycin formulations resulted in a reduced agglomeration tendency and in high fine particle fraction values, thus improving drug deposition. The very low excipients content (about 5% m/m) of these formulations offers the benefit of delivering particularly huge concentrations of antibiotic directly to the site of infection, while minimizing systemic exposure, and may provide a valuable alternative treatment of cystic fibrosis.     

Dry powder inhalation versus wet nebulisation delivery of antibiotics in cystic fibrosis patients

Inhalation of antipseudomonal antibiotics is a cornerstone in treating cystic fibrosis patients. It has shown to be effective in slowing down the process of pulmonary deterioration and decreasing the incidence of infectious exacerbations. The focus is now on innovating drug delivery devices, sometimes combined with specific drug formulations, which allow for the administration of large doses in a short time frame and in a reproducible way. Adaptive aerosol delivery devices are promising, but do not have a distinct position as yet because of the lack of long-term data. The position of dry powder inhalation of antibiotics in cystic fibrosis treatment is still confined to pilot studies. Until more clinical data are available, the suboptimal, conventional jet nebulisers are the mainstay in antipseudomonal inhalation therapy in cystic fibrosis.     

盐酸氨溴索干粉吸入剂的制备工艺

目的优化盐酸氨溴索干粉吸入剂的制备工艺。方法采用喷雾干燥法制备盐酸氨溴索干粉吸入剂,采用双层液体碰撞器测定盐酸氨溴索干粉吸入剂体外沉积率,扫描电镜观察粉粒的形态,激光粒度测定仪测定粒径大小,以产品收率、粉末的空气动力学径、休止角及体外沉积率为考察指标,通过正交设计结合多指标综合评价法优化最佳制备工艺。结果通过正交试验-多指标综合评价,最佳制备工艺为:进口温度110℃、喷液速度1.8 mL.min-1、泵压170 kPa、气流量0.7 m3.min-1。结论按最佳制备工艺制得的干粉收率的质量分数为62.10%,空气动力学径Da 3.05μm,休止角36.16°,沉积率32.05%。正交实验结合多指标综合评价法用于盐酸氨溴索干粉吸入剂制备工艺的优化实用有效。     

Design of fine particles for pulmonary drug delivery

Particle design for inhalation is characterized by advances in particle processing methods and the utilization of new excipients. Processing methods such as spray drying allow control over critical particle design features, such as particle size and distribution, surface energy, surface rugosity, particle density, surface area, porosity and microviscosity. Control of these features has enabled new classes of therapeutics to be delivered by inhalation. These include therapeutics that have a narrow therapeutic index, require a high delivered dose, and/or elicit their action systemically. Engineered particles are also being utilized for immune modulation, with exciting advances being made in the delivery of antibodies and inhaled vaccines. Continued advances are expected to result in ‘smart’ therapeutics capable of active targeting and intracellular trafficking.     

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.     

硫酸特布他林干粉吸入剂制备工艺的优化研究

目的:优化硫酸特布他林干粉吸入剂的制备工艺。方法:采用喷雾干燥技术制备硫酸特布他林干粉吸入剂,采用双层液体碰撞器测定其体外肺沉积率,扫描电镜观察干粉的表观形貌,热重分析仪测定干粉的水分含量,激光粒度测定仪测定粒径大小,以产品收率、水分含量、粉末的空气动力学粒径及体外肺沉积率为考察指标,通过正交设计结合多指标综合评价法优化最佳制备工艺。结果:通过正交试验-多指标综合评价,最佳制备工艺为:喷雾压力190 kPa,干燥风速0.7 m3.min-1,供液速度7.0 mL.min-1,入口温度120℃。结论:按最佳制备工艺制得的干粉收率为50.54%,水分含量为0.467%,空气动力学粒径为1.80μm,体外肺沉积率为55.19%。正交试验结合多指标综合评价法用于硫酸特布他林干粉吸入剂制备工艺的优化有效可用。     

Studies on the spray dried lactose as carrier for dry powder inhalation

The purpose of this study was to investigate the spray dried lactose as carrier for dry powder inhalation (DPI). The lactose particles were prepared by spray drying, then the particle size, shape and crystal form were characterized by laser diffraction, scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The spray dried lactose particles were spherical and amorphous, but would transfer to crystal form when storage humidity was above 32%. Thus, the humidity of the storage environment should be controlled below 30% strictly in order to maintain the amorphous nature of spray dried lactose which is a great benefit to DPI development.     

干粉吸入剂的粉末定量分装设备浅析

干粉吸入剂是一种新兴呼吸道给药剂型,其吸入粉末的分装装置不同于常见的口服固体粉末分装装置。本文综述国际上常用的干粉吸入剂的粉末定量分装装置,包括标准定量器装置装置、真空滚筒分装装置、Xcelodose精确粉末微定量装置等,同时介绍几种较新的、处于研发阶段的粉末分装装置。     

Microparticles of rifampicin: comparison of pulmonary route with oral route for drug uptake by alveolar macrophages,phagocytosis activity and toxicity study in albino rats

Abstract

Context: Tuberculosis (TB) is a chronic infectious disease with increasing incidence of drug resistance. Oral treatment for TB and multidrug resistance (MDR)-TB can have serious side effects. The causative agent of TB, Mycobacterium tuberculosis, resides in alveolar macrophages (AM). Pulmonary administration of anti-TB drugs can help in delivery of high concentration to AM. The ability of AM to phagocytose can also be utilized to generate mycobactericidal nitric oxide (NO) to improve efficacy of anti-TB drugs.

Objective: To compare the uptake of rifampicin (RIF) by AM post oral and pulmonary administration of RIF microparticles (RM) and to compare hepatotoxicity and phagocytosis activity.

Materials and Methods: RM were produced by spray drying process. RM were administered to rats through oral as well as intratracheal route. The uptake of RIF by AM and liver was measured. NO was measured in bronchoalveolar lavage (BAL) fluid. SGOT and SGPT levels were measured in serum.

Results: Significantly higher (p?<?0.05) concentration of RIF was found in AM post intratracheal administration. NO production was also significantly higher but less than toxic level. SGOT and SGPT levels as well as uptake of RIF by liver were indicative of no hepatotoxicity post intratracheal administration.

Discussion: Phagocytosis of RM post intratracheal administration leads to significantly higher drug level in AM as well as production of significantly higher levels of NO.

Conclusion: The administration of RM as dry powder inhalation (DPI) formulation may reduce treatment time of TB and chances of drug resistance TB.     

Inhalation drug delivery devices and emerging technologies

Driven by the pharmaceutical industry to realise the full potential of the lungs for local and systemic treatment of diseases, pulmonary drug delivery by inhalation aerosols has been undergoing rapid development in the past decade. This has led to novel invention of aerosol delivery devices including the propellant-driven metered-dose inhalers, dry powder inhalers and atomisers. Closely coupled to these inhaler devices are the formulations and new technologies that are required to produce particles of defined characteristics for improved delivery. This review highlights some of the recent advances in this expanding field.     

吸入粉雾剂的喷雾工艺及表征研究进展

吸入粉雾剂是改善肺部疾病治疗的研究热点,具有上市产品多、生产工艺成熟、颗粒影响因素多、晶型转化因素多、颗粒表面物性变化等特点。目前,吸入粉雾剂存在产品效用、贮藏及生产工艺因素的关联研究不系统等问题,本文对近年来肺部吸入粉雾剂制备新技术（喷雾冷冻干燥技术、微流控-喷雾技术、模板打印技术）及粉体颗粒物理化学表征新技术（反向气相色谱、原子力显微镜测定技术、能量色散X射线光谱技术、飞行时间-离子质谱法等）进行综述,以期对该剂型的研发提供新的借鉴。     

Pulmonary distribution of nanoceria: comparison of intratracheal,microspray instillation and dry powder insufflation

Particles can be delivered to the respiratory tract of animals using various techniques. Inhalation mimics environmental exposure but requires large amounts of aerosolized NPs over a prolonged dosing time, varies in deposited dose among individual animals, and results in nasopharyngeal and fur particle deposition. Although less physiological, intratracheal (IT) instillation allows quick and precise dosing. Insufflation delivers particles in their dry form as an aerosol. We compared the distribution of neutron-activated ¹⁴¹CeO₂ nanoparticles (5?mg/kg) in rats after (1) IT instillation, (2) left intrabronchial instillation, (3) microspraying of nanoceria suspension and (4) insufflation of nanoceria dry powder. Blood, tracheobronchial lymph nodes, liver, gastrointestinal tract, feces and urine were collected at 5?min and 24?h post-dosing. Excised lungs from each rat were dried at room temperature while inflated at a constant 30?cm water pressure. Dried lungs were then sliced into 50 pieces. The radioactivity of each lung piece and other organs was measured. The evenness index (EI) of each lung piece was calculated [EI = (μCi/mg_piece)/(μCi/mg_lung)]. The degree of EI value departure from 1.0 is a measure of deposition heterogeneity. We showed that the pulmonary distribution of nanoceria differs among modes of administration. Dosing by IT or microspraying resulted in similar spatial distribution. Insufflation resulted in significant deposition in the trachea and in more heterogeneous lung distribution. Our left intrabronchial instillation technique yielded a concentrated deposition into the left lung. We conclude that animal dosing techniques and devices result in varying patterns of particle deposition that will impact biokinetic and toxicity studies.     

Improved lung delivery from a passive dry powder inhaler using an Engineered PulmoSphere powder

Purpose. To assess the pulmonary deposition and pharmacokinetics of an engineered PulmoSphere® powder relative to standard micronized drug when delivered from passive dry powder inhalers (DPIs). Methods. Budesonide PulmoSphere (PS_bud) powder was manufactured using an emulsion-based spray-drying process. Eight healthy subjects completed 3 treatments in crossover fashion: 370 g budesonide PulmoSphere inhaled from Eclipse® DPI at target PIF of 25 L·min^-1 (PS_bud25), and 50 L·min^-1 (PS_bud50), and 800 g of pelletized budesonide from Pulmicort® Turbuhaler® at 60 L·min^-1(TH_bud60). PS_bud powder was radiolabeled with ^99mTc and lung deposition determined scintigraphically. Plasma budesonide concentrations were measured for 12 h after inhalation. Results. Pulmonary deposition (mean ± sd) of PS_bud was 57 ± 7% and 58 ± 8% of the nominal dose at 25 and 50 L·min^-1, respectively. Mean peak plasma budesonide levels were 4.7 (PS_bud25), 4.0 (PS_bud50), and 2.2 ng·ml^-1 (TH_bud60). Median t_max was 5 min after both PS_bud inhalations compared to 20 min for Turbuhaler (P < 0.05). Mean AUCs were comparable after all inhalations, 5.1 (PS_bud25), 5.9 (PS_bud50), and 6.0 (TH_bud60) ng·h·ml^-1. The engineered PS_bud powder delivered at both flow rates from the Eclipse® DPI was twice as efficiently deposited as pelletized budesonide delivered at 60 L·min^-1 from the Turbuhaler. Intersubject variability was also dramatically decreased for PS_bud relative to TH_bud. Conclusion. Delivery of an engineered PulmoSphere formulation is more efficient and reproducible than delivery of micronized drug from passive DPIs.     

月桂酸二乙醇酰胺修饰利福喷丁脂质体的制备、性质及肺部给药

目的制备表面活性剂修饰利福喷丁(RIF)脂质体，进行该脂质体水化性能、载药量、释药速度和肺部给药研究。方法采用薄膜超声法制备利福喷丁脂质体，比较月桂酸二乙醇酰胺(LDEA)，Tween 80和azone修饰利福喷丁脂质体的形态、包封率、释药速度和离体猪肺膜透过性，通过纤支镜进行肺部给药研究。结果RIF-LDEA脂质体粒径在15～50 nm，包封率为83.0%，表观透膜系数Kp为44.29；LD₅₀为675 mg·kg^-1。结论LDEA修饰使利福喷丁脂质体的载药量增加1倍、释药速度的可调性强及安全性好。经纤支镜介导灌注给药治疗肺内膜结核的效果显著。     

Formulation of pH responsive peptides as inhalable dry powders for pulmonary delivery of nucleic acids

Nucleic acids have the potential to be used as therapies or vaccines for many different types of disease, but delivery remains the most significant challenge to their clinical adoption. pH responsive peptides containing either histidine or derivatives of 2,3-diaminopropionic acid (Dap) can mediate effective DNA transfection in lung epithelial cells with the latter remaining effective even in the presence of lung surfactant containing bronchoalveolar lavage fluid (BALF), making this class of peptides attractive candidates for delivering nucleic acids to lung tissues. To further assess the suitability of pH responsive peptides for pulmonary delivery by inhalation, dry powder formulations of pH responsive peptides and plasmid DNA, with mannitol as carrier, were produced by either spray drying (SD) or spray freeze drying (SFD). The properties of the two types of powders were characterised and compared using scanning electron microscopy (SEM), next generation impactor (NGI), gel retardation and in vitro transfection via a twin stage impinger (TSI) following aerosolisation by a dry powder inhaler (Osmohaler™). Although the aerodynamic performance and transfection efficacy of both powders were good, the overall performance revealed SD powders to have a number of advantages over SFD powders and are the more effective formulation with potential for efficient nucleic acid delivery through inhalation.     

Enhanced gene expression and reduced toxicity in mice using polyplexes of low-molecular-weight poly(ethylene imine) for pulmonary gene delivery

The aim of this study was to elicit improved gene expression and decreased cytotoxicity for pulmonary gene therapy by replacing the commonly used carrier 25?kDa branched poly(ethylene imine) (BPEI) by two PEI derivatives, low-molecular-weight PEI (LMWPEI) and polyethylene glycol?grafted PEI (PEGPEI). All polymers were shown to condense DNA to spherical particles of approximately 100?nm. Biocompatibility was investigated in vitro and in vivo. Although transfection was less efficient with LMWPEI-DNA in vitro, this polyplex caused the highest luciferase expression in the mouse lung after intratracheal instillation. While PEGPEI luciferase expression in vitro was approximately three times higher when compared to BPEI, a transfection rate at the level of naked DNA was observed in vivo. LMWPEI polyplexes were located in both the bronchial and alveolar cells, whereas BPEI polyplexes were mainly detected in bronchial cells. LMWPEI combines low cytotoxicity with high transfection efficiency in the mouse lung in vivo, rendering it a promising strategy for pulmonary gene delivery.     

影响干粉吸入剂肺沉积的制剂因素

干粉吸入剂的制剂因素包括药物粉末的处方组成、给药装置类型等,是影响药物肺沉积的主要因素。文中按照药物处方组成将干粉吸入剂分成无载体、药物-载体、药物-添加剂、药物-载体-添加剂4种类型,并分别对其影响肺沉积的制剂因素进行了分析。