Development of dry powder inhaler formulation loaded with alendronate solid lipid nanoparticles: solid-state characterization and aerosol dispersion performance

Long-acting inhaled medicines: Present and future

Inhaled medicines continue to be an essential part of treatment for respiratory diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. In addition, inhalation technology, which is an active area of research and innovation to deliver medications via the lung to the bloodstream, offers potential advantages such as rapid onset of action, enhanced bioavailability, and reduced side effects for local treatments. Certain inhaled macromolecules and particles can also end up in different organs via lymphatic transport from the respiratory epithelium. While the majority of research on inhaled medicines is focused on the delivery technology, particle engineering, combination therapies, innovations in inhaler devices, and digital health technologies, researchers are also exploring new pharmaceutical technologies and strategies to prolong the duration of action of inhaled drugs. This is because, in contrast to most inhaled medicines that exert a rapid onset and short duration of action, long-acting inhaled medicines (LAIM) improve not only the patient compliance by reducing the dosing frequency, but also the effectiveness and convenience of inhaled therapies to better manage patients' conditions. This paper reviews the advances in LAIM, the pharmaceutical technologies and strategies for developing LAIM, and emerging new inhaled modalities that possess a long-acting nature and potential in the treatment and prevention of various diseases. The challenges in the development of the future LAIM are also discussed where active research and innovations are taking place.

Inhalation Dosage Forms: A Focus on Dry Powder Inhalers and Their Advancements

In this review, an extensive analysis of dry powder inhalers (DPIs) is offered, focusing on their characteristics, formulation, stability, and manufacturing. The advantages of pulmonary delivery were investigated, as well as the significance of the particle size in drug deposition. The preparation of DPI formulations was also comprehensively explored, including physico-chemical characterization of powders, powder processing techniques, and formulation considerations. In addition to manufacturing procedures, testing methods were also discussed, providing insights into the development and evaluation of DPI formulations. This review also explores the design basics and critical attributes specific to DPIs, highlighting the significance of their optimization to achieve an effective inhalation therapy. Additionally, the morphology and stability of 3 DPI capsules (Spiriva, Braltus, and Onbrez) were investigated, offering valuable insights into the properties of these formulations. Altogether, these findings contribute to a deeper understanding of DPIs and their development, performance, and optimization of inhalation dosage forms.

Customizable Resveratrol Spray-dried Micro-composites for Inhalation as a Promising Contender for Treatment of Idiopathic Pulmonary Fibrosis

The past decades have witnessed tremendous expansion in utilization of plant-derived medicines as resveratrol (RES) in treating several diseases like idiopathic pulmonary fibrosis (IPF). RES can exhibit its role in treating IPF via its outstanding antioxidant and anti-inflammatory activities. The goal of this work was to formulate RES-loaded spray-dried composite microparticles (SDCMs) suitable for pulmonary delivery via dry powder inhaler (DPI). They were prepared by spray drying of a previously prepared RES-loaded bovine serum albumin nanoparticles (BSA NPs) dispersion using different carriers. RES-loaded BSA NPs, prepared by the desolvation technique, acquired suitable particle size of 177.67±0.95 nm and entrapment efficiency of 98.7±0.35% with perfectly uniform size distribution and high stability. Considering the attributes of the pulmonary route, NPs were co-spray dried with compatible carriers viz. mannitol, dextran, trehalose, leucine, glycine, aspartic acid, and glutamic acid to fabricate SDCMs. All formulations showed suitable mass median aerodynamic diameter less than 5 µm; that is suitable for deep lung deposition. However, the best aerosolization behavior was attained from using leucine with fine particle fraction (FPF) of 75.74%, followed by glycine with FPF of 54.7%. Finally, a pharmacodynamic study was conducted on bleomycin-induced mice, and it strongly revealed the role of the optimized formulations in alleviating PF through suppressing the levels of hydroxyproline, tumor necrosis factor-α and matrix metalloproteinase-9 with obvious improvements in the treated lung histopathology. These findings indicate that in addition to leucine, the glycine amino acid, which is not commonly used yet, is very promising in the formulation of DPIs.

Nanoparticle-containing lyophilized dry powder inhaler formulations optimized using central composite design with improved aerodynamic parameters and redispersibility

Objectives: The aim of this study was to improve the aerodynamic behavior and redispersibility of a lyophilized dry powder inhaler (DPI) formulation containing nanoparticles.Methods: Paclitaxel (PTX)-human serum albumin (HSA) nanoparticles were used as a model, and DPIs containing the nanoparticles were produced by lyophilization using different carriers and carrier ratios. A central composite design was employed to optimize the formulation. L-leucine and mannitol were chosen as independent variables, and mass median aerodynamic diameter (MMAD), emitted fraction, fine particle fraction (FPF), nanoparticle size, polydispersity index (PDI), zeta potential were selected as dependent variables.Results: The water content of DPIs was less than 5% for all DPIs. The cytotoxicity of the DPIs, determined using A549 cells, was due to PTX alone. Particle sizes of 204.3 ± 1.65 nm and 94.3-1353.0 nm were obtained before and after lyophilization, respectively. The developed method resulted in a reduction in the MMAD from 8.148 µm to 5.274 µm, an increase in the FPF from 17.63% to 33.60%, and an increase in the emitted fraction from 77.68% to 97.03%. The physico-chemical characteristics of the optimized formulation were also assessed.Conclusions: In conclusion, this study demonstrates that lyophilization can be used to produce nanoparticle-containing DPI formulations with improved redispersibility and aerodynamic properties.

Spray-Dried Inhalable Powder Formulations of Gentamicin Designed for Pneumonic Plague Therapy in a Mouse Model

Infection with Yersinia pestis (Y. pestis) may cause pneumonic plague, which is inevitably fatal without treatment. Gentamicin (GM), an aminoglycoside antibiotic, is a drug commonly used in the treatment of plague. However, it requires repeated intramuscular or intravenous administration. Pulmonary drug delivery is noninvasive, with the advantages of local targeting and reduced risk of systemic toxicity. In this study, GM powders were prepared using spray-drying technology. The powders displayed good physical and chemical properties and met the requirements for human pulmonary inhalation. The formulation of the powders was optimized using a 3² full factorial design. A formulation of 15% (w/w) of L-leucine was prepared, and the spray-drying process parameters using an inlet temperature of 120°C and a 15% pump rate were determined to produce the best powder. In addition, the optimized GM spray-dried powders were characterized in terms of morphology, crystallinity, powder fluidity, and aerodynamic particle size distribution analysis. In a mouse model of pneumonic plague, we compared the therapeutic effects among three administration routes, including subcutaneous injection, liquid atomization, and dry powder atomization. In conclusion, our data suggest that inhalation therapy with GM spray-dried powders is an effective treatment for pneumonic plague.

Dry Powder Inhalers Based on Chitosan-Mannitol Binary Carriers: Effect of the Powder Properties on the Aerosolization Performance

Carriers play an important role in improving the aerosolization performance of dry powder inhalers (DPIs). Despite that intensive attention had been paid to the establishment of the advanced carriers with controllable physicochemical properties in recent years, the design and optimization of carrier-based DPIs remain an empiricism-based process. DPIs are a powder system of complex multiphase, and thus their physicochemical properties cannot fully explain the powder behavior. A comprehensive exposition of powder properties is demanded to build a bridge between the physicochemical properties of carriers and the aerosolization performance of DPIs. In this study, an FT-4 powder rheometer was employed to explore the powder properties, including dynamic flow energy, aeration, and permeability of the chitosan-mannitol binary carriers (CMBCs). CMBCs were self-designed as an advanced carrier with controllable surface roughness to obtain enhanced aerosolization performance. The specific mechanism of CMBCs to enhance the aerosolization performance of DPIs was elaborated based on the theory of pulmonary delivery processes by introducing powder properties. The results exhibited that CMBCs with appropriate surface roughness had lower special energy, lower aeration energy, and higher permeability. It could be predicted that CMBC-based DPIs had greater tendency to fluidize and disperse in airflow, and the lower adhesion force between particles enabled drugs to be detached from the carrier to achieve higher fine particle fractions. The specific mechanism on how physicochemical properties influenced the aerosolization performance during the pulmonary delivery processes could be figured out with the introduction of powder properties.

Esketamine inhaled as dry powder: Pharmacokinetic, pharmacodynamic and safety assessment in a preclinical study

Ketamine and its enantiomer esketamine have gained much attention in recent years as potent, fast-acting agents for the management of treatment-resistant depression. However, an alternative to oral ketamine administration is required to ensure adequate systemic exposure as the drug undergoes extensive first-pass metabolism. We propose dry powder inhalation as a new esketamine delivery route. Here, we examine the pharmacokinetics, pharmacodynamics, toxicology and safety of this novel esketamine administration method. Esketamine (10 mg/kg) and ketamine racemate (20 mg/kg) were administered to rats by dry powder inhalation, intravenous injection or intratracheal instillation and the pharmacokinetics of these treatments were compared. Analyte concentration of ketamine stereoisomers and their metabolites was assessed by LC-MS/MS method. Esketamine showed a clinically relevant pharmacokinetic profile, with high bioavailability (62%) and relatively low maximum concentration peaks. Esketamine exhibited high penetration of the blood-brain barrier, but pharmacodynamic examinations of brain homogenates showed no changes in selected protein phosphorylation or expression analyzed by the immunoblotting method. We conducted GLP-compliant 14-day and 28-day general toxicity studies in rats and dogs, respectively, subjected to dry esketamine powder inhalation. The maximum daily dosages were 46.5 mg/kg and 36.5 mg/kg, respectively. We also performed pharmacological safety studies. Esketamine inhaled as dry powder had an expected safety profile consistent with its known pharmacological action. None of its observed effects were considered toxicologically significant. The pharmacological safety studies confirmed that the observed effects were transient and that inhaled esketamine had a good safety profile. Hence, our preclinical studies demonstrated that dry powder inhalation is a highly efficacious and safe delivery route for esketamine and may be a viable alternative administration route meriting further clinical development.

Inhalation potential of N-Acetylcysteine loaded PLGA nanoparticles for the management of tuberculosis: In vitro lung deposition and efficacy studies

Several studies have stated that mucus is a critical hurdle for drug delivery to the mucosal tissues. As a result, Polymeric nanoparticles that can overcome mucus barriers are gaining popularity for controlled drug delivery into intra-macrophages to attain high intracellular drug concentration. The present study was aimed to fabricate inhalable N-acetylcysteine (NAC) modified PLGA mucus penetrating particles using the double emulsion method (w/o/w) for target delivery to alveolar macrophages and minimize the dose-related adverse effects, efficiently encapsulate hydrophilic drug, sustain the release profile and prolong the retention time for the management of tuberculosis. Among the numerous formulations, the drug/polymer ratio of 1:10 with 0.50% PVA concentration and sonication time for 2 ​min ​s was chosen for further research. The formulated nanoparticles had a mean particle size of 307.50 ​± ​9.54 ​nm, PDI was 0.136 ​± ​0.02, zeta potential about -11.3 ​± ​0.4 ​mV, decent entrapment efficiency (55.46 ​± ​2.40%), drug loading (9.05 ​± ​0.22%), and excellent flowability. FTIR confirmed that NAC and PLGA were compatible with each other. SEM graphs elucidated that the nanoparticles were spherically shaped with a slightly rough surface whereas TEM analysis ensured the nanometer size nanoparticles and coating of lipid over NPs surface. PXRD spectrum concluded the transformation of the drug from crystalline to amorphous state in the formulation. In vitro release pattern was biphasic started with burst release (64.67 ​± ​1.53% within 12hrs) followed by sustained release over 48hrs thus enabling the prolonged replenishing of NAC. In vitro lung deposition study pronounced that coated NAC-PLGA-MPPs showed favorable results in terms of emitted dose (86.67 ​± ​2.52%), MMAD value (2.57 ​± ​0.12 ​μm), GSD value (1.55 ​± ​0.11 ​μm), and FPF of 62.67 ​± ​2.08% for the deposition and targeting the lungs. Finally, in vitro efficacy studies demonstrated that NAC-PLGA-MPPs presented more prominent antibacterial activity against MTB H37Rv strain as compared to NAC. Hence, PLGA based particles could be a better strategy to deliver the NAC for lung targeting.

A real-time and modular approach for quick detection and mechanism exploration of DPIs with different carrier particle sizes

Dry powder inhalers (DPIs) had been widely used in lung diseases on account of direct pulmonary delivery, good drug stability and satisfactory patient compliance. However, an indistinct understanding of pulmonary delivery processes (PDPs) hindered the development of DPIs. Most current evaluation methods explored the PDPs with over-simplified models, leading to uncompleted investigations of the whole or partial PDPs. In the present research, an innovative modular process analysis platform (MPAP) was applied to investigate the detailed mechanisms of each PDP of DPIs with different carrier particle sizes (CPS). The MPAP was composed of a laser particle size analyzer, an inhaler device, an artificial throat and a pre-separator, to investigate the fluidization and dispersion, transportation, detachment and deposition process of DPIs. The release profiles of drug, drug aggregation and carrier were monitored in real-time. The influence of CPS on PDPs and corresponding mechanisms were explored. The powder properties of the carriers were investigated by the optical profiler and Freeman Technology four powder rheometer. The next generation impactor was employed to explore the aerosolization performance of DPIs. The novel MPAP was successfully applied in exploring the comprehensive mechanism of PDPs, which had enormous potential to be used to investigate and develop DPIs.

Optimization of Solid Lipid Nanoparticles and Nanostructured Lipidic Carriers as Promising Delivery for Gefitinib: Characterization and Invitro Evaluation

Background:

Response surface methodology is a unique tool for the optimization of Solid lipid Nanoparticles and Nanostructured lipid carriers by developing the relationship between dependent and independent variables and exploring their interactions.

Methods:

Central Composite Design and Box Benkhen Design was used to develop optimized formulations of Gefitinib [GEF] Solid Lipid Nanoparticles [SLN] and Nanostructured Lipidic Carriers [NLC]. In the design matrix, the independent variables chosen were the amount of Solid Lipid, Liquid Lipid, and Surfactant and dependent variables were Particle Size and Poly Dispersity Index.

Result:

The GEF-SLN under optimized conditions gave rise to Particle size (187.9 nm ± 1.15), PDI (0.318 ± 0.006), %EE (95.38%±0.14), Zeta Potential (-8.75 mv ±0.18) and GEF-NLC under optimized conditions gave rise to Particle size (188.6 nm± 1.12), PDI (0.395± 0.004), %EE (97.46%± 0.33), Zeta Potential (-5.72 mv± 0.04) respectively. SEM of the Freeze-dried optimized lipidic carriers showed spherical particles. The in vitro experiments proved that Gefitinib in the lipidic carriers is released gradually throughout 24 h.

Conclusion:

This study showed that the response surface methodology could be efficiently applied for the modeling of GEF-SLN & GEF-NLC.

Exploring role of polysaccharides present in Ganoderma lucidium extract powder and probiotics as solid carriers in development of liquisolid formulation loaded with quercetin: A novel study

Ganoderma lucidium extract powder (GLEP) contains various polysaccharides which are well known for their antioxidant and anti-inflammatory actions. Probiotics (PB) are well-established for providing a plethora of health benefits. Hence, use of mushroom polysaccharides and probiotics as carriers to solidify liquisolid formulation is anticipated to function as functional excipients i.e. as adsorbent that may provide therapeutic benefits. Quercetin (QUR) has been used as model lipophilic drug in this study. QUR loaded liquisolid compacts (LSCs) were formulated using Tween 80 as solvent. These were further solidified using a combination of PB and GLEP as carriers. Aerosil-200 (A-200) was used as coating agent. The formulation exhibited very good flow characteristics. Dissolution rate of raw QUR was found to be less than 10% in 60 min while in case of QUR loaded LSCs, more than 90% drug release was observed within 5 min. Absence of crystalline peaks of QUR in the DSC and PXRD reports of LSCs and their porous appearance in SEM micrographs indicate that QUR was successfully incorporated in the LSCs. The developed formulation was found to be stable on storage under accelerated stability conditions.

Unraveling the publication trends in inhalable nano-systems

Nano-systems (size range: 1 ~ 1000 nm) have been widely investigated as pulmonary drug delivery carriers, and the safety of inhaled nano-systems has aroused general interests. In this work, bibliometric analysis was performed to describe the current situation of related literature, figure out the revolutionary trends, and eventually forecast the possible future directions. The relevant articles and reviews from 2001 to 2020 were retrieved from the Web of Science Core Collection. The documents were processed by Clarivate Analytic associated with Web of Science database, Statistical Analysis Toolkit for Informetric, bibliometric online platform and VOSviewer, and the data were visualized. The bibliometric overview of the literature was described, citation analysis was performed, and research hotspots were showcased. The bibliometric analysis of 3362 documents of interest indicated that most of the relevant source titles were in the fields of toxicology, pharmacy, and materials science. The three research hotspots were the biological process of inhalable nano-systems in vivo, the manufacture of inhalable nano-systems, and the impact of nano-systems on human health in the environment. Toxicity and safety have always been the keywords. The USA was the major contributing country, and international collaboration and co-authorship were common phenomena. The general situation and development trend of literature of inhalable nano-systems were summarized. It was anticipated that bibliometrics analysis could provide new ideas for the future research of inhalable nano-systems.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11051-021-05384-1.

Development of New Indonesian Propolis Extract-Loaded Self-emulsifying: Characterization, Stability and Antibacterial Activity

Purpose: This study aimed to prepare, characterize, examine the stability and evaluation of the antibacterial activity of Indonesian propolis extract-loaded self-emulsifying (PESE).

Methods: Oil, emulsifier, and co-emulsifier were selected as the carrier for the PESE formulation through a propolis-extract solubility test on each carrier, followed by evaluation of the nanoemulsion region in a pseudo ternary phase diagram. Pre-concentrate of PESE was prepared with the addition of 150 mg/mL propolis extract followed by characterization for the transmittance, globule size, zeta potential, thermodynamic stability, robustness to dilution, and accelerated stability. The selected formulation was tested for antibacterial activity using a microdilution method.

Results: The PESE characterization produced a clear nanoemulsion with a globule size ranging from 13 to 45 nm and zeta potential of less than −38 mV. The PESE formulation with a composition of 150 mg/mL propolis extract, 20% castor oil, 40%–70% Kolliphor EL, and 10%–40% polyethylene glycol (PEG) 400 were thermodynamically stable. The PESE formulation with the composition of 20% castor oil, 40% Kolliphor EL, and 40% PEG 400 was the optimum formulation that passed the robustness to dilution evaluation and an accelerated stability test for 3 months. The antibacterial activity test on this formulation indicated improved activity against Escherichia coli and Staphylococcus aureus compared with that of propolis extract.

Conclusion: These studies demonstrated that PESE in optimum formulation could be used as an antibacterial, particularly in E. coli and S. aureus.

Glycoside scutellarin enhanced CD-MOF anchoring for laryngeal delivery

It is essential to develop new carriers for laryngeal drug delivery in light of the lack of therapy in laryngeal related diseases. When the inhalable micron-sized crystals of γ-cyclodextrin metal-organic framework (CD-MOF) was utilized as dry powder inhalers (DPIs) carrier with high fine particle fraction (FPF), it was found in this research that the encapsulation of a glycoside compound, namely, scutellarin (SCU) in CD-MOF could significantly enhance its laryngeal deposition. Firstly, SCU loading into CD-MOF was optimized by incubation. Then, a series of characterizations were carried out to elucidate the mechanisms of drug loading. Finally, the laryngeal deposition rate of CD-MOF was 57.72 ± 2.19% improved by SCU, about two times higher than that of CD-MOF, when it was determined by Next Generation Impactor (NGI) at 65 L/min. As a proof of concept, pharyngolaryngitis therapeutic agent dexamethasone (DEX) had improved laryngeal deposition after being co-encapsulated with SCU in CD-MOF. The molecular simulation demonstrated the configuration of SCU in CD-MOF and its contribution to the free energy of the SCU@CD-MOF, which defined the enhanced laryngeal anchoring. In conclusion, the glycosides-like SCU could effectively enhance the anchoring of CD-MOF particles to the larynx to facilitate the treatment of laryngeal diseases.

Lipid Drug Carriers for Cancer Therapeutics: An Insight into Lymphatic Targeting, P-gp, CYP3A4 Modulation and Bioavailability Enhancement

In the treatment of cancer, chemotherapy plays an important role though the efficacy of anti-cancer drug administered orally is limited, due to their poor solubility in physiological medium, inability to cross biological membrane, high Para-glycoprotein (P-gp) mediated drug efflux, and pre-systemic metabolism. These all factors cumulatively reduce drug exposure at the target site leading to multidrug resistance (MDR). Lipid based carriers systems has been explored to overcome solubility and permeability related issues of anti-cancer drugs. The lipid based formulations have also been reported to circumvent the effect of P-gp and CYP3A4. Further long chain triglycerides (LCT) has shown their ability to access Lymphatic route over Medium Chain Triglycerides, as the former has been extensively used for targeting anti-cancer drugs at proliferating cells through lymphatic route. Therefore this review tries to reflect the usefulness of lipid based drug carriers systems (viz. liposome, solid lipid nanoparticle, nano-lipid carriers, self-emulsifying, lipidic pro-drugs) in targeting lymphatic system and overcoming issues related to solubility and permeability of anti-cancer drugs. Moreover, we have also tried to reflect how critically lipid based carriers are important in maximizing therapeutic safety and efficacy of anti-cancer drugs.

Preparation and evaluation of inhalable dry powder containing glucosamine-conjugated gefitinib SLNs for lung cancer therapy

Gefitinib as an epidermal growth factor receptor tyrosine kinase inhibitor has strong potential in lung cancer therapy. However, a major challenge of using gefitinib is its toxicities. In the present study, we developed a dry powder inhaler dosage form containing gefitinib loaded glucosamine targeted solid lipid nanopaticles (Gef-G-SLNs) to locally transfer anticancer agent to the lung tumor. The Gef-G-SLNs were prepared by emulsion-solvent diffusion and evaporation method and optimized with irregular factorial design. The optimized nanoformulation was tested for action against A549 cells. Mannitol or lactose based dry powders were obtained from Gef-G-SLNs after spray drying and characterized using Anderson Cascade Impactor. The optimized formulation had drug loading of 33.29%, encapsulation efficiency of 97.31 ± 0.23%, zeta potential of -15.53 ± 0.47 mV, particle size of 187.23 ± 14.08 nm, polydispersity index of 0.28 ± 0.02 and release efficiency of 35.46 ± 2.25%. The Gef-G-SLNs showed superior anticancer effect compared to free gefitinib. The increased cellular uptake of G-SLNs in A549 cells was demonstrated compared with non-targeted SLNs using flow cytometry and fluorescence microscopy. The produced mannitol based microparticles showed suitable aerodynamic properties with an acceptable mass median aerodynamic diameter of 4.48 µm and fine particle fraction of 44.41%. Therefore, it can be concluded that this formulation represents promising drug delivery to treatment of lung cancer.

Novel approach for real-time monitoring of carrier-based DPIs delivery process via pulmonary route based on modular modified Sympatec HELOS

An explicit illustration of pulmonary delivery processes (PDPs) was a prerequisite for the formulation design and optimization of carrier-based DPIs. However, the current evaluation approaches for DPIs could not provide precise investigation of each PDP separately, or the approaches merely used a simplified and idealized model. In the present study, a novel modular modified Sympatec HELOS (MMSH) was developed to fully investigate the mechanism of each PDP separately in real-time. An inhaler device, artificial throat and pre-separator were separately integrated with a Sympatec HELOS. The dispersion and fluidization, transportation, detachment and deposition processes of pulmonary delivery for model DPIs were explored under different flow rates. Moreover, time-sliced measurements were used to monitor the PDPs in real-time. The Next Generation Impactor (NGI) was applied to determine the aerosolization performance of the model DPIs. The release profiles of the drug particles, drug aggregations and carriers were obtained by MMSH in real-time. Each PDP of the DPIs was analyzed in detail. Moreover, a positive correlation was established between the total release amount of drug particles and the fine particle fraction (FPF) values (R ² = 0.9898). The innovative MMSH was successfully developed and was capable of illustrating the PDPs and the mechanism of carrier-based DPIs, providing a theoretical basis for the design and optimization of carrier-based DPIs.

Lipid-based nanodelivery approaches for dopamine-replacement therapies in Parkinson's disease: From preclinical to translational studies

The incidence of Parkinson's disease (PD), the second most common neurodegenerative disorder, has increased exponentially as the global population continues to age. Although the etiological factors contributing to PD remain uncertain, its average incidence rate is reported to be 1% of the global population older than 60 years. PD is primarily characterized by the progressive loss of dopaminergic (DAergic) neurons and/or associated neuronal networks and the subsequent depletion of dopamine (DA) levels in the brain. Thus, DA or levodopa (l-dopa), a precursor of DA, represent cardinal targets for both idiopathic and symptomatic PD therapeutics. While several therapeutic strategies have been investigated over the past decade for their abilities to curb the progression of PD, an effective cure for PD is currently unavailable. Even DA replacement therapy, an effective PD therapeutic strategy that provides an exogenous supply of DA or l-dopa, has been hindered by severe challenges, such as a poor capacity to bypass the blood-brain barrier and inadequate bioavailability. Nevertheless, with recent advances in nanotechnology, several drug delivery systems have been developed to bypass the barriers associated with central nervous system therapeutics. In here, we sought to describe the adapted lipid-based nanodrug delivery systems used in the field of PD therapeutics and their recent advances, with a particular focus placed on DA replacement therapies. This work initially explores the background of PD; offers descriptions of the most recent molecular targets; currently available clinical medications/limitations; an overview of several lipid-based PD nanotherapeutics, functionalized nanoparticles, and technical aspects in brain delivery; and, finally, presents future perspectives to enhance the use of nanotherapeutics in PD treatment.

Lipid-drug conjugates and associated carrier strategies for enhanced antiretroviral drug delivery

Mortality rate of patients infected with HIV-1 has been significantly reduced by using HAART. However, the virus to date has not been eradicated. Transmission of HIV-1 infection through sexual intercourse remains an ongoing challenge, with increased risk of infection occurring in women. Interestingly, ARV drugs can be chemically linked with lipids to produce lipid-drug conjugates (LDCs). This alters pharmacokinetic properties of ARV drugs and thereby resulting in improved effectiveness. Although LDCs can be administered without a delivery carrier, they are usually incorporated into suitable delivery systems such as lipid nanoparticles, polymeric nanoparticles, micelles, liposomes, emulsions, and carbon nanotubes. Given that LDCs have the potential to improve oral bioavailability, lipophilicity, toxicity, and drug targeting, it is of our great interest to review strategies of lipid-drug conjugation together with their delivery systems for enhanced antiretroviral efficacy.

Transferrin/α-tocopherol modified poly(amidoamine) dendrimers for improved tumor targeting and anticancer activity of paclitaxel

Aim: Transferrin anchored, poly(ethylene glycol) (PEG) and α-tocopheryl succinate (α-TOS) conjugated generation 4 dendrimer has been prepared in order to develop a tumor targeted delivery system of a hydrophobic chemotherapeutic agent, paclitaxel (PTX). Materials & methods: The dendrimers were characterized physicochemically for size, ζ and encapsulation ability. The cellular uptake, cytotoxicity potential and apoptosis of prepared nanoconstruct were evaluated in human cervical epithelial cells monolayer and 3D spheroids. Results & conclusion: G4-TOS-PEG-Tf demonstrated increased cellular uptake, cytotoxicity and apoptotic potential of PTX compared with free PTX and G4-TOS-PEG-PTX. G4-TOS-PEG-Tf-PTX inhibited growth of human cervical epithelial cells spheroids significantly. The newly developed dendrimers hold promise as an efficient delivery system for PTX or other hydrophobic chemotherapeutic agents for targeted delivery to tumors.

Preparation and Characterization of a Dry Powder Inhaler Composed of PLGA Large Porous Particles Encapsulating Gentamicin Sulfate

Purpose: Direct delivery of aminoglycosides to the lungs was under extensive evaluations during the last decades. Because of large particle size, low density and porous structure, large porous particles (LPPs) are versatile carriers for this purpose. In this study, poly (lactic-co-glycolic acid) (PLGA) LPPs encapsulating gentamicin sulfate were prepared and in vitro characteristics of their freeze-dried powder as a dry powder inhaler (DPI) were evaluated.

Methods: To prepare PLGA LPPs, a double emulsification-solvent evaporation method was optimized and gentamicin sulfate was post-loaded in the LPPs. in vitro characteristics including morphological features, thermal behavior, aerodynamic profile and cumulative drug release were evaluated by the scanning electron microscope (SEM), differential scanning calorimetry (DSC), next-generation cascade impactor (NGI) and Franz diffusion cell respectively.

Results: The obtained results revealed that the preparation method was capable to produce spherical large homogenous highly porous particles. 94% of gentamicin sulfate released from LPPs up to 30 minutes. Mass median aerodynamic diameter (MMAD) and fine particle fraction (FPF) were 4.9 µm and 39% respectively.

Conclusion: In this study, dry powder formulation composed of PLGA LPPs encapsulating gentamicin sulfate showed a promising in vitro behavior as a pulmonary delivery carrier. Improvements on the aerodynamic behavior and in vivo evaluations recommended for further developments.

Improving breast cancer therapy using doxorubicin loaded solid lipid nanoparticles: Synthesis of a novel arginine-glycine-aspartic tripeptide conjugated, pH sensitive lipid and evaluation of the nanomedicine in vitro and in vivo

Breast cancer is the leading cause of cancer mortality in women worldwide. To overcome the toxic side effects and multidrug resistance (MDR) during doxorubicin (DOX) chemotherapy, an arginine-glycine-aspartic (RGD) tripeptide modified, pH-sensitive solid lipid nanoparticles (SLNs) is employed in this study. In this study, a RGD conjugated, pH sensitive lipid was synthesized using glycerin monostearate (GMS) and adipic acid dihydrazide (HZ) as lipid materials and named RGD-HZ-GMS. RGD-HZ-GMS was applied to encapsulate DOX to construct a RGD modified, DOX loaded SLNs (RGD-DOX-SLNs). To evaluate the anticancer effect of RGD-DOX-SLNs, breast cancer cell line (MCF-7 cells) and DOX resistant cell line (MCF-7/ADR cells) were used. in vivo tumor suspension and toxicity effects were evaluated on mice bearing MCF-7/ADR cells breast cancer model. RGD-DOX-SLNs had a uniformly spherical shape. The mean particle size and zeta potential of the RGD-DOX-SLNs was 96.3 nm and 35.6 mV, respectively. RGD-DOX-SLNs showed 5.58 fold higher area under the plasma concentration - time curve (AUC) compared with DOX solution. Terminal half life (T_1/2) and peak concentration (C_max) of RGD-DOX-SLNs was 10.85 h and 39.12 ± 2.71 L/kg/h. in vitro and in vivo antitumor results indicate that RGD-DOX-SLNs might be a promising novel lipid carrier which could improve breast cancer therapy.

Ethambutol-Loaded Solid Lipid Nanoparticles as Dry Powder Inhalable Formulation for Tuberculosis Therapy

Ethambutol hydrocloride (EMB) is an anti-tuberculosis drug, which is commonly used as a protection agent against of unrecognized resistance to other drugs employed to treat this disease. Since oral form of EMB has some side effects and cellular toxicity, direct administration of EMB into lungs seems to be an attractive and reasonable option in order to overcome these side effects. Our main goal in this study was assessment of pulmonary administration through dry powder inhaler (DPI) using EMB-loaded solid lipid nanoparticles (SLNs). We prepared EMB-loaded SLNs using two techniques (hot homogenization and ultrasonication). DPI formulations were made by spray drying of EMB-loaded SLNs with and without mannitol. For investigation of flowbility of the prepared powders, Carr's index and Hausner ratio, and for in vitro deposition of the powders, Next Generation Impactor (NGI) analysis were used. The encapsulation efficiency and particle size of obtained particles were higher than 98% and sub-100 nm, respectively. Toxicity investigation of EMB-loaded SLNs via MTT assay showed biocompatibility and non-toxicity of the SLNs. Results of flowability and aerodynamic traits assessment of EMB-loaded SLN DPI powder confirmed the suitability of prepared powders. Overall, the attained results showed that EMB-loaded SLN DPI has high potential for direct treatment of tuberculosis.

PAMAM dendrimers as efficient drug and gene delivery nanosystems for cancer therapy

Drug delivery systems for cancer chemotherapy are employed to improve the effectiveness and decrease the side-effects of highly toxic drugs. Most chemotherapy agents have indiscriminate cytotoxicity that affects normal, as well as cancer cells. To overcome these problems, new more efficient nanosystems for drug delivery are increasingly being investigated. Polyamidoamine (PAMAM) dendrimers are an example of a versatile and reproducible type of nanocarrier that can be loaded with drugs, and modified by attaching target-specific ligands that recognize receptors that are over-expressed on cancer cells. PAMAM dendrimers with a high density of cationic charges display electrostatic interactions with nucleic acids (DNA, siRNA, miRNA, etc.), creating dendriplexes that can preserve the nucleic acids from degradation. Dendrimers are prepared by conducting several successive "generations" of synthetic reactions so their size can be easily controlled and they have good uniformity. Dendrimers are particularly well-suited to co-delivery applications (simultaneous delivery of drugs and/or genes). In the current review, we discuss dendrimer-based targeted delivery of drugs/genes and co-delivery systems mainly for cancer therapy.

Nanomaterials and phase sensitive based signal enhancment in surface plasmon resonance

Measurement of small molecules in extremely dilute concentrations of analyte play an important role in different issues ranging from food industry to biological, pharmaceutical and therapeutical applications. Surface plasmon resonance (SPR) sensors can be a suitable choice for detection of small molecules based on interactions with biomolecules. However, sensitivity of the system for detection of these molecules is very low. Improving sensitivity has been a challenge for years. Therefore, different methods have been used to enhance SPR signals. The SPR signal enhancement using numerous nanomaterials has provided exciting results. Among various nanomaterials, metal nanoparticles (for instance gold, silver and magnetic nanoparticles), quantum dots, nanorads, and carbon-based nanostructures have got much attention due to ease in fabrication, appropriate size and shape. In addition to the advantages provided by using nanomaterials, signal enhancement provided by the appropriate use of phase information of the reflected light could be also important to improve SPR sensitivity. Phase-sensitive SPR sensors are able to detect infinitesimal changes in external properties of target while traditional type of SPR cannot demonstrate these changes. This article provides an overview on signal enhancment in SPR using nanomaterials and properties of light. We also discuss on recent progresses of the field, describing basic concepts concerning nanostructures as well as phase-sensitive sensors as platform for enhancement of signal in SPR.

Microparticles containing erlotinib-loaded solid lipid nanoparticles for treatment of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) patients with sensitizing mutations in the exons 18-21 of the epithelial growth factor receptor (EGFR) gene show increased kinase activity of EGFR. Hence, tyrosine kinase inhibitors (TKIs) such as erlotinib (ETB) have commonly been used as the second line therapeutic option for the treatment of metastatic NSCLC. While the ETB is available as an oral dosage form, the local delivery of this TKI to the diseased cells of the lung may ameliorate its therapeutic impacts. In the current study, we report on the development of ETB-loaded solid lipid nanoparticle (SLN) based formulation of dry powder inhaler (ETB-SLN DPI). ETB-SLNs were formulated using designated amount of compritol/poloxamer 407. The engineered ETB-SLNs showed sub-100 nm spherical shape with an encapsulation efficiency of 78.21%. MTT assay and DAPI staining revealed that the ETB-SLNs enhanced the cytotoxicity of cargo drug molecules in the human alveolar adenocarcinoma epithelial A549 cells as a model for NSCLC. To attain the ETB-SLN DPI, the ETB-SLNs were efficiently spray dried into microparticles (1-5 μm) along with mannitol. The ETB-SLN DPI powder displayed suitable flowability and aerodynamic traits. The Carr's Index, Hausner ratio and Next Generation Impactor (NGI) analyses confirmed deep inhalation pattern of the formulation. Based on these findings, we propose the ETB-SLN DPI as a promising treatment modality for the NSCLC patients.

Liquid Crystalline Nanoparticles as an Ophthalmic Delivery System for Tetrandrine: Development, Characterization, and In Vitro and In Vivo Evaluation

The purpose of this study was to develop novel liquid crystalline nanoparticles (LCNPs) that display improved pre-ocular residence time and ocular bioavailability and that can be used as an ophthalmic delivery system for tetrandrine (TET). The delivery system consisted of three primary components, including glyceryl monoolein, poloxamer 407, and water, and two secondary components, including Gelucire 44/14 and amphipathic octadecyl-quaternized carboxymethyl chitosan. The amount of TET, the amount of glyceryl monoolein, and the ratio of poloxamer 407 to glyceryl monoolein were selected as the factors that were used to optimize the dependent variables, which included encapsulation efficiency and drug loading. A three-factor, five-level central composite design was constructed to optimize the formulation. TET-loaded LCNPs (TET-LCNPs) were characterized to determine their particle size, zeta potential, entrapment efficiency, drug loading capacity, particle morphology, inner crystalline structure, and in vitro drug release profile. Corneal permeation in excised rabbit corneas was evaluated. Pre-ocular retention was determined using a noninvasive fluorescence imaging system. Finally, pharmacokinetic study in the aqueous humor was performed by microdialysis technique. The optimal formulation had a mean particle size of 170.0 ± 13.34 nm, a homogeneous distribution with polydispersity index of 0.166 ± 0.02, a positive surface charge with a zeta potential of 29.3 ± 1.25 mV, a high entrapment efficiency of 95.46 ± 4.13 %, and a drug loading rate of 1.63 ± 0.07 %. Transmission electron microscopy showed spherical particles that had smooth surfaces. Small-angle X-ray scattering profiles revealed an inverted hexagonal phase. The in vitro release assays showed a sustained drug release profile. A corneal permeation study showed that the apparent permeability coefficient of the optimal formulation was 2.03-fold higher than that of the TET solution. Pre-ocular retention capacity study indicated that the retention of LCNPs was significantly longer than that of the solution (p < 0.01). In addition, a pharmacokinetic study of rabbit aqueous humors demonstrated that the TET-LCNPs showed 2.65-fold higher ocular bioavailability than that of TET solution. In conclusion, a LCNP system could be a promising method for increasing the ocular bioavailability of TET by enhancing its retention time and permeation into the cornea.

Advances in Controlled Drug Delivery for Treatment of Osteoporosis

Osteoporosis, which is characterized by resorption of bone exceeding formation, remains a significant human health concern, and the impact of this condition will only increase with the "graying" of the worldwide population. This review focuses on current and emerging approaches for delivering therapeutic agents to restore bone remodeling homeostasis. Well-known antiresorptive and anabolic agents, such as estrogen, estrogen analogs, bisphosphonates, calcitonin, and parathyroid hormone, along with newer modulators and antibodies, are primarily administered orally, intravenously, or subcutaneously. Although these treatments can be effective, continuing problems include patient noncompliance and adverse systemic or remote-site effects. Controlled drug delivery via polymeric, targeted, and active release systems extends drug half-life by shielding against premature degradation and improves bioavailability while also providing prolonged, sustained, or intermittent release at therapeutic doses to more effectively treat osteoporosis and associated fracture risk.

The Impact of Variables on Particle Size of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers; A Comparative Literature Review

During the past decade, pharmaceutical science has seen rapid growth in interest for nanoscale materials. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are popular research topics recently introduced as nano-scale drug carriers; they have shown numerous merits in drug delivery. Size is the most important index in a nanocarrier affecting its drug delivery efficiency. The influence of preparation conditions and type of lipidic components on the size of SLN and NLC in comparable states seems to be interesting for researchers who investigate these types of carriers. This review highlights the results of SLN and NLC particle size and size distribution comparisons.