Pullulan-Based Spray-Dried Mucoadhesive Microparticles for Sustained Oromucosal Drug Delivery.

Mucoadhesive microparticles for oromucosal drug delivery offer several advantages, including intimate contact with the mucosa, delivery to less accessible regions, extended residence time, sustained drug release, reduced irritation, and improved patient compliance. In this study, pullulan was used to prepare mucoadhesive spray-dried microparticles for delivering benzydamine hydrochloride (BZH) to oral mucosa. The BZH-pullulan spray-dried microparticles had a mean size of <25 µm with an angle of repose values between 25.8-36.6°. Pullulan markedly extended drug-release time to >180 min, ~9 times greater than the duration (i.e., 20 min) reportedly achieved by chitosan. Kinetic analysis showed the drug-release rate was concentration dependent and jointly controlled by drug diffusion and polymer chain relaxation. Further, pullulan was mucoadhesive and was able to retain up to 78.8% w/w of microencapsulated gold nanoparticle probes at the mucosal membrane. These data strongly suggest that BZH-pullulan microparticles have great potential for oromucosal drug delivery, by providing elongated residence time in situ and sustained drug release for the treatment of local diseases.

Particulate bioaerogels for respiratory drug delivery.

The bioaerogel microparticles have been recently developed for respiratory drug delivery and attract fast increasing interests. These highly porous microparticles have ultralow density and hence possess much reduced aerodynamic diameter, which favour them with greatly enhanced dispersibility and improved aerosolisation behaviour. The adjustable particle geometric dimensions by varying preparation methods and controlling operation parameters make it possible to fabricate bioaerogel microparticles with accurate sizes for efficient delivery to the targeted regions of respiratory tract (i.e. intranasal and pulmonary). Additionally, the technical process can provide bioaerogel microparticles with the opportunities of accommodating polar, weak polar and non-polar drugs at sufficient amount to satisfy clinical needs, and the adsorbed drugs are primarily in the amorphous form that potentially can facilitate drug dissolution and improve bioavailability. Finally, the nature of biopolymers can further offer additional advantageous characteristics of improved mucoadhesion, sustained drug release and subsequently elongated time for continuous treatment on-site. These fascinating features strongly support bioaerogel microparticles to become a novel platform for effective delivery of a wide range of drugs to the targeted respiratory regions, with increased drug residence time on-site, sustained drug release, constant treatment for local and systemic diseases and anticipated better-quality of therapeutic effects.

Dual functional pullulan-based spray-dried microparticles for controlled pulmonary drug delivery.

Two main challenges are associated with current spray-dried microparticles for inhalation, including the enhancement of aerosolization performance of microparticles and the creation of sustained drug release for continuous treatment on-site. For achieving these purposes, pullulan was explored as a novel excipient to prepare spray-dried inhalable microparticles (with salbutamol sulphate, SS, as a model drug), which were further modified by additives of leucine (Leu), ammonium bicarbonate (AB), ethanol and acetone. It was demonstrated that all pullulan-based spray-dried microparticles had improved flowability and enhanced aerosolization behavior, with the fine particle (<4.46 µm) fraction of 42.0-68.7% w/w, much higher than 11.4% w/w of lactose-SS. Moreover, all modified microparticles showed augmented emitted fractions of 88.0-96.9% w/w, over 86.5% w/w of pullulan-SS. The pullulan-Leu-SS and pullulan-(AB)-SS microparticles demonstrated further increased fine particle (<1.66 µm) doses of 54.7 µg and 53.3 µg respectively, surpassing that (49.6 µg) of pullulan-SS, suggesting an additionally increased drug deposition in the deep lungs. Furthermore, pullulan-based microparticles revealed sustained drug release profiles with elongated time (60mins) over the control (2mins). Clearly, pullulan has a great potential to construct dual functional microparticles for inhalation with improved pulmonary delivery efficiency and sustained drug release on-site.

Changes of serum uric acid and its clinical correlation in children with dilated cardiomyopathy.

BACKGROUND: Dilated cardiomyopathy (DCM) is the most common type of childhood cardiomyopathy and uric acid (UA) is considered closely associated with cardiovascular disease. There are few reports about the relationship between serum UA level and DCM in children, and the present study aimed to analyze the changes and clinical correlation of the two. METHODS: The clinical data of 49 children under 16 years old and who were hospitalized with DCM, and 44 healthy children who underwent physical examination in the same period at Tianjin Children's Hospital from June 2015 to November 2019 were analyzed retrospectively. RESULTS: The 49 children in the case group included 17 males and 32 females, aged from 2 to 172 months. The case group were divided into New York Heart Association (NYHA) functional class I (n=2), class II (n=17), class III (n=11), and class IV (n=19). The 44 healthy children selected as the control group included 20 males and 24 females aged from 2 to 161 months. The serum UA level was detected, and an ultrasonic cardiogram was conducted in each child. The serum UA level, left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), and left atrial diameter (LAD) of the case group were higher than that of the control group, while the left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were lower than that of the control group, and significant statistical differences were seen between the two groups (P<0.01). The serum UA level, LVEDD, LVESD, and LAD of NYHAIII-IV class patients were higher than that of the NYHAI-II class, but LVEF and LVFS were lower than that of the NYHA I-II class, and there were significant statistical differences between the two groups (P<0.01). Statistical correlations were seen between the serum UA level and NYHA functional class, LVEDD, LVESD, LAD, LVEF, and LVFS (rs=0.599, 0.567, 0.579, 0.475, -0.333, -0.341, respectively, P<0.05). CONCLUSIONS: Elevated serum UA levels exist in children with DCM and correlate with NYHA functional class and ultrasonic values. Change in serum UA levels may be used as a biomarker reflecting the severity of DCM in children.

Successful biosynthesis of natural antioxidant ergothioneine in Saccharomyces cerevisiae required only two genes from Grifola frondosa.

BACKGROUND: Ergothioneine (EGT) has a unique antioxidant ability and diverse beneficial effects on human health. But the content of EGT is very low in its natural producing organisms such as Mycobacterium smegmatis and mushrooms. Therefore, it is necessary to highly efficient heterologous production of EGT in food-grade yeasts such as Saccharomyces cerevisiae. RESULTS: Two EGT biosynthetic genes were cloned from the mushroom Grifola frondosa and successfully heterologously expressed in Saccharomyces cerevisiae EC1118 strain in this study. By optimization of the fermentation conditions of the engineered strain S. cerevisiae EC1118, the 11.80 mg/L of EGT production was obtained. With daily addition of 1% glycerol to the culture medium in the fermentation process, the EGT production of the engineered strain S. cerevisiae EC1118 can reach up to 20.61 mg/L. CONCLUSION: A successful EGT de novo biosynthetic system of S. cerevisiae containing only two genes from mushroom Grifola frondosa was developed in this study. This system provides promising prospects for the large scales production of EGT for human health.

Preparation of Lipid-Peptide-DNA (LPD) Nanoparticles and Their Use for Gene Transfection.

Therapeutic gene delivery systems offer the potential for the treatment of a range of inherited and acquired inherited diseases. In contrast with viral gene vectors, the nonviral gene vectors provide a safer alternative and additional advantages such as the improved delivery efficiency, low cost, and often unlimited capacity to package DNA. Here we describe the preparation of a nonviral gene delivery technique based on lipid-peptide-DNA (LPD) complexes. The size of LPD particles is in the nanometer range. The use of these nanoparticulate LPDs results in high efficiency transfections and a high level of gene expression in vitro. LPDs provide a convenient and efficient tool for gene delivery in gene therapy.

Preparation of Spray-Dried Nanoparticles for Efficient Drug Delivery to the Lungs.

The use of nanoparticulate systems for pulmonary drug delivery offers a number of advantages including significantly improved delivery efficiency to deep lung and the improved bioavailability. The traditional nanoparticle manufacturing process such as ball/jet milling often yields large aggregates, which could detrimentally inhibit the effective delivery of drug particles to the lower respiratory tract. Here we report an alternative technique of spray-drying the microemulsions to produce nanoparticles (<100 nm) that can be dispersed homogenously in the propellant to form an extremely stable pressurized metered-dose inhaler (pMDI) formulations. Such nanoparticulate formulations provide an ideal tool for pulmonary drug delivery.

Innovative pMDI formulations of spray-dried nanoparticles for efficient pulmonary drug delivery.

For drug delivery to the lungs, the aerodynamic size of drug particles plays a predominant role in determining the sites of deposition in the airway, and the particles with the size less than 2µm are highly expected as they will be preferably delivered to the ideal site of alveolar regions. In this paper, a novel platform technology has been developed, where the water (containing pharmaceutically active agents)-in-oil (w/o) microemulsions were spray-dried to generate nanosized drug particles that were able to be homogeneously dispersed in the propellant to form an exceptionally stable suspensions with no precipitates or flocculates during a long time storage. High fine particle (<5.8µm) fraction (∼70% w/w) was achieved, irrespectively of drug molecular size and storage time. This platform technology works pretty well on chemical drugs (i.e. salbutamol sulphate) and biotherapeutics (i.e. insulin) for the generation of nanoparticles, and the nanoparticle pMDI formulations were homogeneous, stable and of high delivery efficiency to the lungs, representing an ideal way for pulmonary delivery.

Preparation of nanoparticles by spray-drying and their use for efficient pulmonary drug delivery.

The use of nanoparticulate systems for pulmonary drug delivery offers a number of advantages including the significantly improved delivery efficiency to the deep lung and the improved bioavailability. The traditional nanoparticle manufacturing process such as ball/jet milling may generate large aggregates, which could detrimentally inhibit the effective delivery of drug particles to the lower respiratory way. Here we report an alternative technique of spray-drying nanoemulsion to produce nanoparticles (<100 nm) that can be dispersed homogenously in the propellant to form an extremely stable pressurized metered dose inhaler formulation. Such nanoparticulate formulations dramatically improve the efficiency of drug delivery to the lungs, and therefore provide an ideal tool for pulmonary drug delivery.

Preparation of lipid:peptide:DNA (LPD) nanoparticles and their use for gene transfection.

Therapeutic gene delivery systems offer the potential for the treatment of a range of inherited and acquired inherited diseases. In contrast with viral gene vectors, the nonviral gene vectors provide a safer alternative and additional advantage such as the improved delivery efficiency, low cost, and often unlimited capacity to package DNA. Here we describe preparation of nonviral gene delivery technique based on lipid:peptide:DNA (LPD) complexes. The size of LPD particles is in the nanometre range. The use of these nanoparticulate LPDs results in high efficiency transfections and a high level of gene expression in vitro. LPDs provide a convenient and efficient tool for gene therapy for the gene delivery.

Doxorubicin-loaded PEG-PCL copolymer micelles enhance cytotoxicity and intracellular accumulation of doxorubicin in adriamycin-resistant tumor cells.

BACKGROUND: Multidrug resistance remains a major obstacle to successful cancer chemotherapy. Some chemical multidrug resistance inhibitors, such as ciclosporin and verapamil, have been reported to reverse resistance in tumor cells. However, the accompanying side effects have limited their clinical application. In this study, we have developed a novel drug delivery system, ie, a polyethyleneglycol-polycaprolactone (PEG-PCL) copolymer micelle encapsulating doxorubicin, in order to circumvent drug resistance in adriamycin-resistant K562 tumor cells. METHODS: Doxorubicin-loaded diblock copolymer PEG-PCL micelles were developed, and the physicochemical properties of these micelles, and accumulation and cytotoxicity of doxorubicin in adriamycin-resistant K562 tumor cells were studied. RESULTS: Doxorubicin-loaded micelles were prepared using a solvent evaporation method with a diameter of 36 nm and a zeta potential of +13.8 mV. The entrapment efficiency of doxorubicin was 48.6% ± 2.3%. The micelles showed sustained release, increased uptake, and cellular cytotoxicity, as well as decreased efflux of doxorubicin in adriamycin-resistant K562 tumor cells. CONCLUSION: This study suggests that PEG-PCL micelles have the potential to reverse multidrug resistance in tumor cells.

The use of sodium carboxymethylcellulose in the preparation of spray-dried proteins for pulmonary drug delivery.

The use of sodium carboxymethylcellulose (NaCMC) as a spray-drying excipient in the preparation of inhalable formulations of proteins was investigated, using alkaline phosphatase as a model functional protein. Two spray-dried powders were investigated: a control powder comprising 100% (w/w) alkaline phosphatase and a test powder comprising 67% (w/w) NaCMC and 33% (w/w) alkaline phosphatase. Following physicochemical characterisation, the powders were prepared as both dry powder inhaler (DPI) and pressurised metered dose inhaler (pMDI) formulations. The aerosolisation performance of the formulations was assessed using a Multi-Stage Liquid Impinger, both immediately after preparation and over a 16-week storage period. Formulating the control powder as a DPI resulted in a poor fine particle fraction (FPF: 10%), whereas the FPF of the NaCMC-modified DPI formulation was significantly greater (47%). When the powders were formulated as pMDI systems, the control and NaCMC-modified powders demonstrated FPFs of 52% and 55%, respectively. Following storage, reduced FPF was observed for all formulations except the NaCMC-modified pMDI system; the performance of this formulation following storage was statistically equivalent to that immediately following preparation. Co-spray-drying proteins and peptides with NaCMC may therefore offer an alternative method for the preparation of stable and respirable pMDI formulations for pulmonary delivery.

Novel pMDI formulations for pulmonary delivery of proteins.

In this paper, we demonstrate that co-spray-drying a model protein with sodium carboxymethylcellulose (NaCMC) protects protein integrity during spray-drying, and that the resultant spray-dried powders can be successfully dispersed in hydrofluoroalkane (HFA) propellant to prepare pressurised metered dose (pMDI) formulations that exhibit high respirable fractions. The spray-dried powders were formulated as HFA-134a pMDI suspensions in the absence of any other excipients (e.g. surfactants) or co-solvents (e.g. ethanol). The in vitro aerosolisation profile of these systems was assessed using the twin stage impinger; fine particle fractions (FPF) > or = 50% of the recovered dose were obtained. Following storage for five months, the aerosolisation performance was reassessed; the NaCMC-free formulation demonstrated a significant decrease in FPF, whereas the performance of the NaCMC-modified formulations was statistically equivalent to their initial performance. Thus, formulation of pMDI suspensions using NaCMC-based spray-dried powders is a promising approach for the pulmonary delivery of proteins and peptides.

Spray-dried powders for pulmonary drug delivery.

Powders for inhalation are traditionally prepared using a destructive micronization process such as jet milling to reduce the particle size of the drug to 2-5 mum. The resultant particles are typically highly cohesive and display poor aerosolization properties, necessitating the addition of a coarse carrier particle to the micronized drug to improve powder flowability. Spray-drying technology offers an alternative, constructive particle production technique to the traditional destructive approach, which may be particularly useful when processing biotechnology products that could be adversely affected by high-energy micronization processes. Advantages of spray drying include the ability to incorporate a wide range of excipients into the spray-drying feedstock, which could modify the aerosolization and stability characterizations of the resultant powders, as well as modify the drug release and absorption profiles following inhalation. This review discusses some of the reasons why pulmonary drug delivery is becoming an increasingly popular route of administration and describes the various investigations that have been undertaken in the preparation of spray-dried powders for pulmonary drug delivery.

Chitosan-modified dry powder formulations for pulmonary gene delivery.

PURPOSE: Spray-drying is an effective process for preparing micron-dimensioned particles for pulmonary delivery. Previously, we have demonstrated enhanced dispersibility and fine particle fraction of spray-dried nonviral gene delivery formulations using amino acids or absorption enhancers as dispersibility-enhancing excipients. In this study, we investigate the use of the cationic polymer chitosan as a readily available and biocompatible dispersibility enhancer. METHODS: Lactose-lipid:polycation:pDNA (LPD) powders were prepared by spray-drying and post-mixed with chitosan or spray-dried chitosan. In addition, the water-soluble chitosan derivative, trimethyl chitosan, was added to the lactose-LPD formulation before spray-drying. RESULTS: Spray-dried chitosan particles, displaying an irregular surface morphology and diameter of less than 2 microm, readily adsorbed to lactose-LPD particles following mixing. In contrast with the smooth spherical surface of lactose-LPD particles, spray-dried trimethyl chitosan-lactose-LPD particles demonstrated increased surface roughness and a unimodal particle size distribution (mean diameter 3.4 microm), compared with the multimodal distribution for unmodified lactose-LPD powders (mean diameter 23.7 microm). The emitted dose and in vitro deposition of chitosan-modified powders was significantly greater than that of unmodified powders. Moreover, the inclusion of chitosan mediated an enhanced level of reporter gene expression. CONCLUSIONS: In summary, chitosan enhances the dispersibility and in vitro pulmonary deposition performance of spray-dried powders.

Enhanced dispersibility and deposition of spray-dried powders for pulmonary gene therapy.

Spray-drying represents a viable alternative to freeze-drying for preparing dry powder dispersions for delivering macromolecules to the lung. The dispersibility of spray-dried powders is limited however, and needs to be enhanced to improve lung deposition and subsequent biological activity. In this study, we investigate the utility of leucine as a dry powder dispersibility enhancer when added prior to spray-drying a model non-viral gene therapy formulation (lipid:polycation:pDNA, LPD). Freeze-dried lactose-LPD, spray-dried lactose-LPD and spray-dried leucine-lactose-LPD powders were prepared. Scanning electron microscopy showed that leucine increased the surface roughness of spray-dried lactose particles. Particle size analysis revealed that leucine-containing spray-dried powders were unimodally dispersed with a mean particle diameter of 3.12 microm. Both gel electrophoresis and in vitro cell (A549) transfection showed that leucine may compromise the integrity and biological functionality of the gene therapy vector. The deposition of the leucine containing powder was however significantly enhanced as evidenced by an increase in gene expression mediated by dry powder collected at lower stages of a multistage liquid impinger (MSLI). Further studies are required to determine the potential of leucine as a ubiquitous dispersibility enhancer for a variety of pulmonary formulations.