Spray-drying of solid lipid nanoparticles (SLN TM)

Experimental approaches to evaluate solid lipid nanoparticle-based drug delivery systems

Solid lipid nanoparticles (SLNs) are potential drug carriers due to the several advantages they offer. The physicochemical stability of lipid carriers varies significantly due to their diverse compositions and structures. Appropriate analytical methods are required for the complete characterization of SLNs. Physicochemical characterization includes analysis of bulk properties like particle size, size distribution, zeta potential, morphology, stability, polymorphism, crystallinity, and molecular level properties like microenvironments within nanoparticles and their interactions with drugs. Moreover, drug loading, drug entrapment efficiency, and drug release kinetics are essential parameters to evaluate the efficacy of SLNs as drug delivery systems. In addition to testing the physicochemical stability and functionality of SLN formulations, it is essential to investigate their desired actions through in vivo studies, which are beyond the scope of this article. This review briefly discusses the different experimental techniques and their applications in the field of solid lipid nanoparticles. These techniques can also be used to characterize nanostructure lipid carriers, which are second-generation lipid nanoparticles.

Solid Lipid Nanoparticles as an Innovative Lipidic Drug Delivery System

In order to overcome some of the drawbacks of traditional formulations, increasing emphasis has recently been paid to lipid-based drug delivery systems. Solid lipid nanoparticles (SLNs) are promising delivery methods, and they hold promise because of their simplicity in production, capacity to scale up, biocompatibility, and biodegradability of formulation components. Other benefits could be connected to a particular route of administration or the makeup of the ingredients being placed into these delivery systems. This article aims to review the significance of solid lipid nanocarriers, their benefits and drawbacks, as well as their types, compositions, methods of preparation, mechanisms of drug release, characterization, routes of administration, and applications in a variety of delivery systems with a focus on their efficacy.

Liposome preparation of alpha-arbutin: stability and toxicity assessment using mouse B16F10 melanoma cells

Melanoma is the most aggressive type of skin cancer, with few therapeutic alternatives following metastasis development. In recent years, drug delivery-associated nanotechnology has shown promising targeted results with diminished adverse effects compared to conventional treatments. This study aimed to (1) examine the effects of plant-derived α-arbutin, a natural compound and (2) compare these findings with bioactively developed liposomes containing α-arbutin utilizing the B16-F10 murine melanoma cell line as a model. Liposomes were obtained through reversed-phase evaporation by applying a spray dryer to assess their stability. The following biologic assays were measured cytotoxicity/antiproliferative (MTT, Neutral Red, and dsDNA PicoGreen). In addition, the levels of melanin and purinergic enzymes were also measured. The production of reactive oxygen species (ROS) and nitric oxide (NO) was determined as a measure of oxidative state. Treatment with nano-liposome containing alpha-arbutin induced a significant 68.4% cytotoxicity, similar to the positive control, in the B16-F10 murine melanoma cell line at 72 hr. Further, arbutin and liposomes containing alpha-arbutin increased levels of ROS and nitrite formation at 72 hr at the highest concentration (100 and 300 µg/ml) of treatments. Arbutin and liposomes containing alpha-arbutin reduced melanin levels at all tested concentrations. In addition, arbutin and alpha-arbutin containing liposomes lowered nucleotides (AMP, ADP, and ATP) and nucleoside (adenosine) levels in melanoma cells. Evidence suggests that α-arbutin containing liposome can be considered as an alternative immunosuppressive agent stimulated in melanoma treatment.

Design and development of mRNA and self-amplifying mRNA vaccine nanoformulations

The rapid evolution of mRNA vaccines, highlighted by Pfizer-BioNTech and Moderna's COVID-19 vaccines, has transformed vaccine development and therapeutic approaches. Self-amplifying mRNA (saRNA) vaccines, a groundbreaking advancement in RNA-based vaccines, offer promising possibilities for disease prevention and treatment, including potential applications in cancer and neurodegenerative diseases. This review explores the complex design and development of these innovative vaccines, with a focus on their nanoscale formulations that utilize nanotechnology to improve their delivery and effectiveness. It articulates the fundamental principles of mRNA and saRNA vaccines, their mechanisms of action, and the role of synthetic mRNA in eliciting immune responses. The review further elaborates on various nanoscale delivery systems (e.g., lipid nanoparticles, polymeric nanoparticles and other nanocarriers), emphasizing their advantages in enhancing mRNA stability and cellular uptake. It addresses advanced nanoscale delivery techniques such as microfluidics and discusses the challenges in formulating mRNA and saRNA vaccines. By incorporating the latest technologies and current research, this review provides a thorough overview of recent mRNA and saRNA nanovaccines advancements, highlighting their potential to revolutionize vaccine technology and broaden clinical applications.

Combining the potential of 3D printed buccal films and nanostructured lipid carriers for personalised cannabidiol delivery

Cannabidiol (CBD) has been recognized for its numerous therapeutic benefits, such as neuroprotection, anti-inflammatory effects, and cardioprotection. However, CBD has some limitations, including unpredictable pharmacokinetics and low oral bioavailability. To overcome the challenges associated with CBD delivery, we employed Design of Experiments (DoE), lipid carriers, and 3D printing techniques to optimize and develop buccal film loaded with CBD-NLCs. Three-factor Box-Behnken Design was carried out to optimise the NLCs and analyse the effect of independent factors on dependent factors. The emulsification-ultrasonication technique was used to prepare the NLCs. A pressure-assisted micro-syringe printing technique was used to produce the films. The produced films were studied for physicochemical, and mechanical properties, release profiles, and predicted in vivo performance. The observed particle size of the NLCs ranged from 12.17 to 84.91 nm whereas the PDI varied from 0.099 to 0.298. Lipid and sonication time positively affected the particle size whereas the surfactant concentration was inversely related. CBD was incorporated into the optimal formulation and the observed particle size, PDI, and zeta potential for the CBD-NLCs were 94.2 ± 0.47 nm, 0.11 ± 0.01 and - 11.8 ± 0.52 mV. Hydroxyethyl cellulose (HEC)-based gel containing the CBD-NLCs was prepared and used as a feed for 3D printing. The CBD-NLCs film demonstrated a slow and sustained in vitro release profile (84. 11 ± 7.02% in 6 h). The predicted AUC0-10 h, Cmax, and Tmax were 201.5 µg·h/L, 0.74 µg/L, and 1.28 h for a film with 0.4 mg of CBD, respectively. The finding demonstrates that a buccal film of CBD-NLCs can be fabricated using 3D printing.

Several Applications of Solid Lipid Nanoparticles in Drug Delivery

Rapid progress is being made in the area of nanotechnology; solid lipid nanoparticles are currently at the forefront of research and development. They have the capability of becoming employed in an extensive number of applications, including the delivery of medications, clinical treatment, and research, in addition to uses in other areas of academic inquiry that could benefit from their utilisation. This article presents a thorough analysis of solid lipid nanoparticles, covering subjects such as their goals, preparation strategy, applications, advantages, and possible remedies for the issues that have been raised. This review provides a discussion of solid lipids that is both in-depth and comprehensive. Studies that investigate the manner in which SLNs are prepared and the routes via which they are administered are typical. Aspects concerning the route of administration of SLNs as well as the destiny of the carriers in vivo are also investigated in this paper.

Integrated continuous manufacturing of inhalable remdesivir nanoagglomerate dry powders: Design, optimization and therapeutic potential for respiratory viral infections

While inhalable nanoparticle-based dry powders have demonstrated promising potential as next-generation respiratory medicines, erratic particle redispersibility and poor manufacturing reproducibility remain major hurdles hindering their translation from bench to bedside. We developed a one-step continuous process for fabricating inhalable remdesivir (RDV) nanoagglomerate dry powder formulations by integrating flash nanoprecipitation and spray drying. The nanosuspension formulation was optimized using a three-factor Box-Behnken design with a z-average particle size of 233.3 ± 2.3 nm and < 20% size change within six hours. The optimized inhalable nanoagglomerate dry powder formulation produced by spray drying showed adequate aqueous redispersibility (Sf/Si = 1.20 ± 0.01) and in vitro aerosol performance (mass median aerodynamic diameter of 3.80 ± 0.58 µm and fine particle fraction of 39.85 ± 10.16%). In A549 cells, RDV nanoparticles redispersed from the inhalable nanoagglomerate powders displayed enhanced and accelerated RDV cell uptake and negligible cytotoxicity at therapeutic RDV concentrations. No statistically significant differences were observed in the critical quality attributes of the inhalable nanoagglomerate powders produced from the continuous manufacturing and standalone batch modes. This work demonstrates the feasibility of large-scale continuous manufacturing of inhalable nanoagglomerate dry powder formulations, which pave the way for their clinical translation.

Influence of Polymer Concentration on Drying of SPION Dispersions by Electrospinning

To improve the physical stability of nanoparticle dispersions, several methods for their transformation into stable and easily dispersible dry products have been investigated thus far. Recently, electrospinning was shown to be a novel nanoparticle dispersion drying method, which addresses the crucial challenges of the current drying methods. It is a relatively simple method, but it is affected by various ambient, process, and dispersion parameters, which impact the properties of the electrospun product. The aim of this study was, thus, to investigate the influence of the most important dispersion parameter, namely the total polymer concentration, on the drying method efficiency and the properties of the electrospun product. The formulation was based on a mixture of hydrophilic polymers poloxamer 188 and polyethylene oxide in the weight ratio of 1:1, which is acceptable for potential parenteral application. We showed that the total polymer concentration of prior-drying samples is closely related to their viscosity and conductivity, also affecting the morphology of the electrospun product. However, the change in morphology of the electrospun product does not affect the efficiency of SPION reconstitution from the electrospun product. Regardless of the morphology, the electrospun product is not in powder form and is therefore safer to handle compared to powder nanoformulations. The optimal total polymer concentration in the prior-drying SPION dispersion, which enables the formation of an easily dispersible electrospun product with high SPION-loading (65% (w/w)) and fibrillar morphology, was shown to be 4.2% (w/v).

Solid Lipid Nanoparticles vs. Nanostructured Lipid Carriers: A Comparative Review

Solid-lipid nanoparticles and nanostructured lipid carriers are delivery systems for the delivery of drugs and other bioactives used in diagnosis, therapy, and treatment procedures. These nanocarriers may enhance the solubility and permeability of drugs, increase their bioavailability, and extend the residence time in the body, combining low toxicity with a targeted delivery. Nanostructured lipid carriers are the second generation of lipid nanoparticles differing from solid lipid nanoparticles in their composition matrix. The use of a liquid lipid together with a solid lipid in nanostructured lipid carrier allows it to load a higher amount of drug, enhance drug release properties, and increase its stability. Therefore, a direct comparison between solid lipid nanoparticles and nanostructured lipid carriers is needed. This review aims to describe solid lipid nanoparticles and nanostructured lipid carriers as drug delivery systems, comparing both, while systematically elucidating their production methodologies, physicochemical characterization, and in vitro and in vivo performance. In addition, the toxicity concerns of these systems are focused on.

Solid Lipid Nanoparticles: Review of the Current Research on Encapsulation and Delivery Systems for Active and Antioxidant Compounds

Various active compounds are easily damaged, so they need protection and must be easily absorbed and targeted. This problem can be overcome by encapsulating in the form of solid lipid nanoparticles (SLNs). Initially, SLNs were widely used to encapsulate hydrophobic (non-polar) active compounds because of their matched affinity and interactions. Currently, SLNs are being widely used for the encapsulation of hydrophilic (polar) and semipolar active compounds, but there are challenges, including increasing their entrapment efficiency. This review provides information on current research on SLNs for encapsulation and delivery systems for active and antioxidant compounds, which includes various synthesis methods and applications of SLNs in various fields of utilization. SLNs can be developed starting from the selection of solid lipid matrices, emulsifiers/surfactants, types of active compounds or antioxidants, synthesis methods, and their applications or utilization. The type of lipid used determines crystal formation, control of active compound release, and encapsulation efficiency. Various methods can be used in the SLN fabrication of active compounds and hydrophilic/hydrophobic antioxidants, which have advantages and disadvantages. Fabrication design, which includes the selection of lipid matrices, surfactants, and fabrication methods, determines the characteristics of SLNs. High-shear homogenization combined with ultrasonication is the recommended method and has been widely used because of the ease of preparation and good results. Appropriate fabrication design can produce SLNs with stable active compounds and antioxidants that become suitable encapsulation systems for various applications or uses.

Solid Lipid Nanoparticles for Drug Delivery

Solid lipid nanoparticles are promising carriers that allow for the delivery of poorly water-soluble drugs and have the potential to achieve sustained drug release or targeted delivery to the site of interest. Here we describe the preparation of solid lipid nanoparticles by forming a microemulsion at an elevated temperature which, upon cooling, yields a suspension of solid nanoparticles. This nanotemplate engineering method is inexpensive, reproducible, and easy to scale up.

Development of Solid Lipid Nanoparticles as Dry Powder: Characterization and Formulation Considerations

Solid lipid nanoparticles (SLNs) are lipid-based colloidal systems used for the delivery of active compounds. Although SLNs have many benefits, they show important issues due to physical and chemical instability phenomena during storage. For these reasons, it is highly desirable to have a dried SLN formulation available. Therefore, the aim of the project was to identify suitable methods to obtain a dry powder formulation from an SLN suspension. The nanoparticle suspension was dried using both freeze- and spray-drying techniques. The suitability of these methods in obtaining SLN dry powders was evaluated from the analyses of nanotechnological parameters, system morphology and thermal behavior using differential scanning calorimetry. Results pointed out that both drying techniques, although at different yields, were able to produce an SLN dry powder suitable for pharmaceutical applications. Noteworthily, the freeze-drying of SLNs under optimized conditions led to a dry powder endowed with good reconstitution properties and technological parameters similar to the starting conditions. Moreover, freeze-thaw cycles were carried out as a pretest to study the protective effect of different cryoprotectants (e.g., glucose and mannitol with a concentration ranging from 1% to 10% w/v). Glucose proved to be the most effective in preventing particle growth during freezing, thawing, and freeze-drying processes; in particular, the optimum concentration of glucose was 1% w/v.

Processing of Lipid Nanodispersions into Solid Powders by Spray Drying

Spray drying is a promising technology for drying lipid nanodispersions. These formulations can serve as carrier systems for poorly water-soluble active pharmaceutical ingredients (APIs) that are loaded into the lipid matrix to improve their bioavailability. Once the API-loaded nanocarriers have been further processed into solid dosage forms, they could be administered orally, which is usually preferred by patients. Various solid lipids as well as oils were used in this study to prepare lipid nanodispersions, and it was shown that their nanoparticulate properties could be maintained when lactose in combination with SDS was used as matrix material in the spray-drying process. In addition, for lipid nanoemulsions loaded with fenofibrate, a good redispersibility with particle sizes below 300 nm at a lipid content of 26.8 wt.% in the powders was observed. More detailed investigations on the influence of the drying temperature yielded good results when the inlet temperature of the drying air was set at 110 °C or above, enabling the lactose to form an amorphous matrix around the embedded lipid particles. A tristearin suspension was developed as a probe to measure the temperature exposure of the lipid particles during the drying process. The results with this approach indicate that the actual temperature the particles were exposed to during the drying process could be higher than the outlet temperature.

Approaches for designing and delivering solid lipid nanoparticles of distinct antitubercular drugs

Tuberculosis (TB) is still the biggest infectious disease among adults globally, which effects the social and biological lives of patients as well as the economic liability of healthcare systems. Current treatment regime has challenges with drug resistant (MDR/XDR) strains and the failure of standard therapeutic interventions against these TB strains. In the recent years, several nanocarrier-based drug delivery systems developed (including lipid-based) with anti-tuberculosis drugs via targeted delivery to improve the therapeutic outcomes. In this review, we attempt to summarize on the composition of the reported solid lipid-based particles (SLNPs), their various production methodologies, and properties of the delivery system, and their influence on cellular and pharmacokinetic aspects are also discussed. Besides, we have highlighted anti-TB drugs delivering via lipid-based systems have shown promising outcomes, however clinical translation of such systems is still under investigation. Based on recent advancements and reports, it is recommended that future efforts be made to accelerate the translational development of lipid-based nanocarriers to improve TB treatment.

Microfluidic production of mRNA-loaded lipid nanoparticles for vaccine applications

INTRODUCTION

During past years, lipid nanoparticles (LNPs) have emerged as promising carriers for RNA delivery, with several clinical trials focusing on both infectious diseases and cancer. More recently, the success of messenger RNA (mRNA) vaccines for the treatment of severe diseases such as acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is partially justified by the development of LNPs encapsulating mRNA for efficient cytosolic delivery.

AREAS COVERED

This review examines the production and formulation of LNPs by using microfluidic devices, the status of mRNA-loaded LNPs therapeutics and explores spray drying process, as a promising dehydration process to enhance LNP stability and provide alternative administration routes.

EXPERT OPINION

Microfluidic techniques for preparation of LNPs based on organic solvent injection method promotes the generation of stable, uniform, and monodispersed nanoparticles enabling higher encapsulation efficiency. In particular, the application of microfluidics for the fabrication of mRNA-loaded LNPs is based on rapid mixing of small volumes of ethanol solution containing lipids and aqueous solution containing mRNA. Control of operating parameters and formulation has enabled the optimization of nanoparticle physicochemical characteristics and encapsulation efficiency.

Spray drying siRNA-lipid nanoparticles for dry powder pulmonary delivery

While all the siRNA drugs on the market target the liver, the lungs offer a variety of currently undruggable targets which could potentially be treated with RNA therapeutics. Hence, local, pulmonary delivery of RNA nanoparticles could finally enable delivery beyond the liver. The administration of RNA drugs via dry powder inhalers offers many advantages related to physical, chemical and microbial stability of RNA and nanosuspensions. The present study was therefore designed to test the feasibility of engineering spray dried lipid nanoparticle (LNP) powders. Spray drying was performed using 5% lactose solution (m/V), and the targets were set to obtain nanoparticle sizes after redispersion of spray-dried powders around 150 nm, a residual moisture level below 5%, and RNA loss below 15% at maintained RNA bioactivity. The LNPs consisted of an ionizable cationic lipid which is a sulfur-containing analog of DLin-MC3-DMA, a helper lipid, cholesterol, and PEG-DMG encapsulating siRNA. Prior to the spray drying, the latter process was simulated with a novel dual emission fluorescence spectroscopy method to preselect the highest possible drying temperature and excipient solution maintaining LNP integrity and stability. Through characterization of physicochemical and aerodynamic properties of the spray dried powders, administration criteria for delivery to the lower respiratory tract were fulfilled. Spray dried LNPs penetrated the lung mucus layer and maintained bioactivity for >90% protein downregulation with a confirmed safety profile in a lung adenocarcinoma cell line. Additionally, the spray dried LNPs successfully achieved up to 50% gene silencing of the house keeping gene GAPDH in ex vivo human precision-cut lung slices at without increasing cytokine levels. This study verifies the successful spray drying procedure of LNP-siRNA systems maintaining their integrity and mediating strong gene silencing efficiency on mRNA and protein levels both in vitro and ex vivo. The successful spray drying procedure of LNP-siRNA formulations in 5% lactose solution creates a novel siRNA-based therapy option to target respiratory diseases such as lung cancer, asthma, COPD, cystic fibrosis and viral infections.

Review on the Scale-Up Methods for the Preparation of Solid Lipid Nanoparticles

Solid lipid nanoparticles (SLNs) are an alternate carrier system to liposomes, polymeric nanoparticles, and inorganic carriers. SLNs have attracted increasing attention in recent years for delivering drugs, nucleic acids, proteins, peptides, nutraceuticals, and cosmetics. These nanocarriers have attracted industrial attention due to their ease of preparation, physicochemical stability, and scalability. These characteristics make SLNs attractive for manufacture on a large scale. Currently, several products with SLNs are in clinical trials, and there is a high possibility that SLN carriers will quickly increase their presence in the market. A large-scale manufacturing unit is required for commercial applications to prepare enough formulations for clinical studies. Furthermore, continuous processing is becoming more popular in the pharmaceutical sector to reduce product batch-to-batch differences. This review paper discusses some conventional methods and the rationale for large-scale production. It further covers recent progress in scale-up methods for the synthesis of SLNs, including high-pressure homogenization (HPH), hot melt extrusion coupled with HPH, microchannels, nanoprecipitation using static mixers, and microemulsion-based methods. These scale-up technologies enable the possibility of commercialization of SLNs. Furthermore, ongoing studies indicate that these technologies will eventually reach the pharmaceutical market.

Applications and perspectives of polyphenol-loaded solid lipid nanoparticles and nanostructured lipid carriers for foods

Imbalanced nutrition in modern society is one of the reasons for disorders, such as cancer, cardiovascular disease, and diabetes, which have attracted the interest in bioactives (particularly polyphenols) to assist in the balanced diet of modern people. Although stability can be maintained during preparation and storage, the ingested polyphenols undergo harsh gastrointestinal digestion processes, resulting in limited bioaccessibility and low gut-epithelial permeation and bioavailability. Several lipid-based formulations have been proposed to overcome these issues. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) have also been highlighted as carrier systems for the oral delivery of lipophilic bioactives, including polyphenols. This paper summarizes the research on the ingredients, production methods, post-processing procedures, general characteristics, and advantages and disadvantages of SLNs and NLCs. Overall, this paper reviews the applications and perspectives of polyphenol-loaded SLNs and NLCs in foods, as well as their regulation, production, storage, and economic feasibility.

Spray dried powders for nasal delivery: Process and formulation considerations

Powders for nasal delivery have been recognized as advantageous dosage forms over liquids due to increased stability and residence time on nasal mucosa, with improved bioavailability. They can be manufactured by spray-drying, allowing the optimization of the particle properties that are critical to guarantee nasal deposition, as size and shape. It is also a scalable and flexible method already explored extensively in the pharmaceutical industry. However, it is important to understand how process parameters, particle physical properties and formulation considerations affect the product performance. Hence, this review aims to provide an overview of nasal powder formulation and processing through spray drying, with an emphasis on the variables that impact on performance. To this purpose, we describe the physical, biological and pharmacological phenomena prior to drug absorption as well as the most relevant powder properties. Formulation considerations including qualitative and quantitative composition are then reviewed, as well as manufacturing considerations including spray drying relevant parameters.

Orodispersible Films: A Delivery Platform for Solid Lipid Nanoparticles?

To overcome the poor bioavailability observed for many newly developed active pharmaceutical ingredients (APIs), an appropriate formulation strategy is necessary. One approach is the formulation of these substances in solid lipid nanoparticles and their further processing into solid dosage forms. A promising and innovative oral delivery platform could be orodispersible films (ODFs). ODFs were already investigated more closely, e.g., for the administration of API nanoparticles, and proved their suitability for this formulation approach. The current study was aimed at investigating if the HPMC (hydroxypropyl methyl cellulose) film matrix is also suitable to serve as an appropriate delivery platform for solid lipid nanoparticles. Dependent on the type of triglyceride nanoparticles embedded in the film matrix and the formulation of the lipid particles, lipid contents of up to 54 wt.% could be realized in the film matrix without the loss of the nanoparticulate state. Good mechanical properties were confirmed for these films by determining the tensile strength as well as the elongation before breakage. Interestingly, processing of a lipid suspension into this solid dosage form led to a significantly reduced transformation of the lipid particles from the metastable α- into the stable β-polymorph. This could prove very beneficial when the lipid particles are loaded with APIs.

Inhalation delivery of repurposed drugs for lung cancer: Approaches, benefits and challenges

Lung cancer (LC) is one of the leading causes of mortality accounting for almost 25% of cancer deaths throughout the world. The shortfall of affordable and effective first-line chemotherapeutics, the existence of resistant tumors, and the non-optimal route of administration contribute to poor prognosis and high mortality in LC. Administration of repurposed non-oncology drugs (RNODs) loaded in nanocarriers (NCs) via inhalation may prove as an effective alternative strategy to treat LC. Furthermore, their site-specific release through inhalation route using an appropriate inhalation device would offer improved therapeutic efficacy, thereby reducing mortality and improving patients' quality of life. The current manuscript offers a comprehensive overview on use of RNODs in LC treatment with an emphasis on their inhalation delivery and the associated challenges. The role of NCs to improve lung deposition and targeting of RNODs via inhalation are also elaborated. In addition, information about various RNODs in clinical trials for the treatment of LC, possibility for repurposing phytoceuticals against LC via inhalation and the bottlenecks associated with repurposing RNODs against cancer are also highlighted. Based on the reported studies covered in this manuscript, it was understood that delivery of RNODs via inhalation has emerged as a propitious approach. Hence, it is anticipated to provide effective first-line treatment at an affordable cost in debilitating LC from low and middle-income countries (LMIC).

Development, optimization, and in vitro evaluation of atorvastatin calcium and vinpocetine codelivery by solid lipid nanoparticles for cancer therapy

Background

The main objective of the present study was to formulate, optimize and characterize solid lipid nanoparticles (SLNs) loaded with Atorvastatin Calcium (ATS) and Vinpocetine (VIN) as a potential drug delivery system to improve its solubility and assess its anti-tumor activity on cell lines. The SLNs were formulated by emulsification with high speed homogenization followed by probe sonication. Central composite design was selected for optimization. Drug: lipid ratio, surfactant: co-surfactant ratio and homogenization speed were considered critical process parameters (CPP) to study the effects on critical quality attributes (CQA) of SLNs i.e. particle size, percent entrapment efficiency (% EE) and percent drug loading (% DL).

Results

The optimized (F3) SLNs formulations were characterized by transmission electron microscopy (TEM), X- ray diffraction (X-RD), in vitro drug release by dialysis bag method and stability studies. In vitro cell line studies were performed on HepG2, MCF 7 and melanoma B16 F10 cell line. The optimized F3 formulation showed a particle size of 323 ± 6 nm, poly dispersity index (PDI) 0.333 ± 0.02, Zeta potential (ZP) − 30.4 ± 0.66 emv with % EE 64.69 ± 1.1; 65.98 ± 0.91 of ATS and VIN respectively. In vitro release (F3) of ATS and VIN in PBS pH 7.4 was found to be 89.45% and 91.86%, respectively, up to 24 h.

Conclusions

In vitro cell line study demonstrated that SLNs enhanced the anti-cancer activity of ATS, VIN on all the stated cell lines when compared with free drugs. Combination index (CI) for HEPG2 was 0.8, which signified synergistic effect. The results exhibited that SLNs is effective, stable and had enhanced activity against HepG2, MCF 7 and melanoma B16 F10 cell lines.

Solid Lipid Nanoparticles (SLNs): An Advanced Drug Delivery System Targeting Brain through BBB

The blood-brain barrier (BBB) plays a vital role in the protection and maintenance of homeostasis in the brain. In this way, it is an interesting target as an interface for various types of drug delivery, specifically in the context of the treatment of several neuropathological conditions where the therapeutic agents cannot cross the BBB. Drug toxicity and on-target specificity are among some of the limitations associated with current neurotherapeutics. In recent years, advances in nanodrug delivery have enabled the carrier system containing the active therapeutic drug to target the signaling pathways and pathophysiology that are closely linked to central nervous system (CNS) disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), multiple sclerosis (MS), brain tumor, epilepsy, ischemic stroke, and neurodegeneration. At present, among the nano formulations, solid lipid nanoparticles (SLNs) have emerged as a putative drug carrier system that can deliver the active therapeutics (drug-loaded SLNs) across the BBB at the target site of the brain, offering a novel approach with controlled drug delivery, longer circulation time, target specificity, and higher efficacy, and more importantly, reducing toxicity in a biomimetic way. This paper highlights the synthesis and application of SLNs as a novel nontoxic formulation strategy to carry CNS drugs across the BBB to improve the use of therapeutics agents in treating major neurological disorders in future clinics.

Engineered mucoadhesive microparticles of formoterol/budesonide for pulmonary administration

In the present study, a multi-component system comprised of dipalmitylphospatidylcholine (DPPC), Chitosan, Lactose, and L-Leucine was developed for pulmonary delivery. Microparticles were engineered by the spray drying process and the selection of the critical parameters was performed by applying experimental design. The microcarriers with the appropriate size and yield were co-formulated with two active pharmaceutical ingredients (APIs), namely, Formoterol fumarate and Budesonide, and they were further investigated. All formulations exhibited spherical shape, appropriate aerodynamic performance, satisfying entrapment efficiency, and drug load. Their physicochemical properties were evaluated using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and Differential Scanning Calorimetry (DSC). The aerodynamic particle size characterization was determined using an eight-stage Andersen cascade impactor, whereas the release of the actives was monitored in vitro in simulated lung fluid. Additional evaluation of the microparticles' mucoadhesive properties was performed by ζ-potential measurements and ex vivo mucoadhesion study applying a falling liquid film method using porcine lung tissue. Cytotoxicity and cellular uptake studies in Calu-3 lung epithelial cell line were conducted to further investigate the safety and efficacy of the developed formulations.

Improving the survival of Lactobacillus plantarum NRRL B-1927 during microencapsulation with ultra-high-pressure-homogenized soymilk as a wall material

Probiotic foods and supplements have been shown to offer multiple potential health benefits to consumers. Dried probiotic cultures are increasingly used by the food industry because they are easily handled, transported, stored, and used in different applications. However, drying technologies often expose probiotic cells to extreme environmental conditions that reduces cell viability. Hence, this study aimed to evaluate the effect of using ultra high-pressure homogenization (UHPH) on soymilk's microencapsulating ability, and the resultant effect on the survivability of probiotic Lactobacillus plantarum NRRL B-1927 (LP) during drying. Liquid suspensions containing LP (~10⁹ CFU/g of solids) were prepared by suspending LP cultures in soymilk which had been either treated with UHPH at 150 MPa or 300 MPa or left untreated. LP suspensions were then dried by concurrent spray drying (CCSD), mixed-flow spray drying (MXSD) or freeze-drying (FD). Cell counts of LP were determined before and after microencapsulation. Moisture, water activity, particle size and morphology of LP powders were also characterized. LP powders produced with 300 MPa treated soymilk had 8.7, 6.4, and 2 times more cell counts than those produced with non-UHPH treated soymilk during CCSD, MXSD, and FD, respectively. In the 300 MPa treated samples, cell survival (%) of LP during drying was the highest in MXSD (83.72) followed by FD (76.31) and CCSD (34.01). Using soymilk treated at higher UHPH pressures resulted in LP powders with lower moisture content, smaller particle sizes and higher agglomeration. LP powders produced via MXSD showed higher agglomeration and fewer signs of thermal damage than powders produced via CCSD. This study demonstrates that UHPH improves the effectiveness of soymilk as a microencapsulant for probiotics, creating probiotic powders that could be used in plant-based and non-dairy foods.

Development of solid lipid microparticles by melt-emulsification/spray-drying processes as carriers for pulmonary drug delivery

The aim of this study was to optimize the parameters of the complex melt-emulsification process coupled with the spray-drying, in order to maintain the balance between solid lipid microparticles (SLMs) powders aerodynamic performance and salbutamol sulfate release rate. Quality target product profile was identified and risk management and principal component analysis were used to guide formulation development. Obtained dry powders for inhalation (DPIs) were evaluated in terms of SLMs size distribution, morphology, true density, drug content, solid state characterization studies, in vitro aerosol performance and in vitro drug release. SLMs micrographs indicated spherical, porous particles. Selected powders showed satisfactory aerosol performance with a mean mass aerodynamic diameter of around 3 μm and acceptable fine particle fraction (FPF). Addition of trehalose positively affected SLMs aerodynamic properties. The results of in vitro dissolution testing indicated that salbutamol sulfate release from the tested SLMs formulations was modified, in comparison to the raw drug release. In conclusion, SLMs in a form of DPIs were successfully developed and numerous factors that affects SLMs properties were identified in this study. Further research is required for full understanding of each factor's influence on SLMs properties and optimization of DPIs with maximized FPFs.

Spray drying as an advantageous strategy for enhancing pharmaceuticals bioavailability

Spray drying is an efficient technique that is used not only for rapid evaporation of the solvent from different systems but also for designing ultra-fine particles with various desirable characteristics. The obtained powders demonstrate reasonably narrow size distribution with a submicron-to-micron size range. It is one of the recent techniques applied to present acceptable solutions to enhance the absorption and bioavailability of some challenging drugs. In view of that, the purpose of this review is to shed some light on the wide variety of the recently developed fine particulate products that can be produced from spray-drying technique. This article reports the most outstanding advantages and challenges that could be overcome by exploiting the spray-drying technique for the production of different pharmaceuticals, including pure drug particles and drug-loaded polymeric carriers. The potential of this technique, whether used alone or in combination with other methods, in order to develop reproducible and scalable procedures for the best translation of bench-to-bedside innovation of pharmaceutical products is hereby discussed.

Microencapsulation of Lactobacillus plantarum NRRL B-1927 with Skim Milk Processed via Ultra-High-Pressure Homogenization

Several health benefits are associated with the consumption of probiotic foods. Lyophilized probiotic cultures are commonly used to manufacture probiotic-containing products. Spray drying (SDR) is a cost-effective process to microencapsulate probiotics. However, the high temperatures of the drying air in SDR can inactivate significant numbers of probiotic cells. Ultra-high-pressure homogenization (UHPH) processing can modify the configuration of proteins found in skim milk which may increase its protective properties as microencapsulating agent towards probiotic cells during SDR. The aim of this study was to evaluate the effect of microencapsulating probiotic Lactobacillus plantarum NRRL B-1927 (LP) with UHPH-treated skim milk after SDR or freeze drying (FD). Dispersions containing LP were made with either UHPH-treated (at 150 MPa or 300 MPa) or untreated skim milk and dried via concurrent SDR (CCSD), mixed-flow SDR (MXSD) or FD. Higher cell survival (%) of LP was found in powders microencapsulated with 150 MPa-treated skim milk than in those microencapsulated with non-UHPH-treated and 300 MPa-treated skim milk via FD followed by MXSD and CCSD, respectively. Increasing UHPH pressures increased the particle size of powders produced via CCSD; and reduced particle agglomeration of powders produced via MXSD and FD. This study demonstrated that UHPH processes improves the effectiveness of skim milk as a microencapsulating agent for LP, creating powders that could be used in probiotic foods.

Nanocrystals of Novel Valerolactam-Fenbendazole Hybrid with Improved in vitro Dissolution Performance

Valero-fenbendazole (VAL-FBZ) is a novel hybrid compound with in vitro anthelmintic activity, designed and synthesized to address the global problem of resistance to anthelmintic compounds. This new molecule derives from fenbendazole (FBZ), a well-known commercially available benzimidazole used in veterinary medicine despite its poor water solubility. In this work, we report for the first time a strategy to solve the solubility problems of FBZ and VAL-FBZ by means of self-dispersible nanocrystals (SDNC). Nanocrystals were prepared by media milling followed by a spray-drying step, and a comprehensive and exhaustive structural and physicochemical characterization was carried out, in order to understand the systems and their behavior. The formulation poloxamer 188 (P188):FBZ 1:1 turned out with the best process yield (53%) and re-dispersability properties, particle size average of 258 nm, and polydispersity index of 0.2 after redispersion in water. The dissolution profile showed a markedly increased dissolution rate compared with the simple mixture of the components (80% FBZ dissolved in 15 min from the SDNC vs 14% from the control formulation). FTIR spectroscopy, thermal analysis, and X-Ray Powder Diffraction (XRPD) studies showed no chemical interactions between components and an extensive confocal Raman microscopy analysis of the formulations showed very homogeneous spatial distribution of components in the SDNC samples. This manufacturing process was then successfully transferred for preparing and characterizing VAL-FBZ:P188 (1:1) SDNC with similar results, suggesting the promising interest of a novel anthelmintic with improved biopharmaceutical behavior. In conclusion, new FBZ and VAL-FBZ SDNC with improved dissolution rate were successfully prepared and characterized. Graphical abstract.

Analytical Techniques for the Assessment of Drug-Lipid Interactions and the Active Substance Distribution in Liquid Dispersions of Solid Lipid Microparticles (SLM) Produced de novo and Reconstituted from Spray-Dried Powders

Solid lipid microparticles (SLM) can be presented as liquid suspension or spray-dried powder. The main challenge in SLM technology is to precisely determine the location of the active substance (API) in the different compartments of the formulation and its changes during SLM processing. Therefore, the purpose of the research was to assess the distribution of the API and to investigate the nature of the API-lipid interaction when the formulation was subjected to spray drying, with an indication of the most suitable techniques for this purpose. SLM were prepared with two various lipids (Compritol or stearic acid) and two model APIs: cyclosporine (0.1% and 1% w/w) and spironolactone (0.1% and 0.5% w/w). Physicochemical characterizations of the formulations, before and after spray drying, were performed by differential scanning calorimetry (DSC), atomic force microscopy (AFM), Raman spectroscopy and nuclear magnetic resonance (NMR). The API distribution between the SLM matrix, SLM surface and the aqueous phase was determined, and the release study was performed. It was demonstrated that, in general, the spray drying did not affect the drug release and drug distribution; however, some changes were observed in the SLM with Compritol and when the API concentration was lower. Only in the SLM with stearic acid was a change in the DSC curves noted. Measurements with the AFM technique proved to be a useful method for detecting differences in the surface properties between the placebo and API-loaded SLM, while the Raman spectroscopy did not show such evident differences.

Formulating SLN and NLC as Innovative Drug Delivery Systems for Non-Invasive Routes of Drug Administration

Colloidal carriers diverge depending on their composition, ability to incorporate drugs and applicability, but the common feature is the small average particle size. Among the carriers with the potential nanostructured drug delivery application there are SLN and NLC. These nanostructured systems consist of complex lipids and highly purified mixtures of glycerides having varying particle size. Also, these systems have shown physical stability, protection capacity of unstable drugs, release control ability, excellent tolerability, possibility of vectorization, and no reported production problems related to large-scale. Several production procedures can be applied to achieve high association efficiency between the bioactive and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. The whole set of unique advantages such as enhanced drug loading capacity, prevention of drug expulsion, leads to more flexibility for modulation of drug release and makes Lipid-based nanocarriers (LNCs) versatile delivery system for various routes of administration. The route of administration has a significant impact on the therapeutic outcome of a drug. Thus, the non-invasive routes, which were of minor importance as parts of drug delivery in the past, have assumed added importance drugs, proteins, peptides and biopharmaceuticals drug delivery and these include nasal, buccal, vaginal and transdermal routes. The objective of this paper is to present the state of the art concerning the application of the lipid nanocarriers designated for non-invasive routes of administration. In this manner, this review presents an innovative technological platform to develop nanostructured delivery systems with great versatility of application in non-invasive routes of administration and targeting drug release.

Nanoparticle-mediated macrophage targeting-a new inhalation therapy tackling tuberculosis

Despite the potent clinical efficacy of linezolid (LNZ) against drug-resistant tuberculosis, its safety and tolerability remain of major concern. Our objective is to develop antitubercular inhalable LNZ nano-embedded microparticles. In this context, LNZ incorporated in non-structured lipid carriers (NLCs) was characterized in terms of colloidal, morphological, thermal, and release profiles. The potential of LNZ-NLCs to cross mucosal barriers and invade alveolar macrophages (AM, MH-S cells) was appraised. In vivo proof of concept was accomplished via orotracheal administration to mice. Respirable microparticles prepared by spray drying NLCs with diluents were assessed for their size, shape, flowability, aerosolization performance, and lung deposition pattern. NLCs (809-827 nm in size, zeta potential - 37.4 to - 58.9 mV) ensued 19% LNZ loading and pH-independent sustained release. Penetration studies revealed 73% LNZ crossing mucus within 1 h. Meanwhile, viability assay on A549 cells ensured an IC50 of 1.2 and 0.32 mg/mL for plain and LNZ-NLCs, respectively. CLSM confirmed phagocytosis of NLCs by MH-S macrophages, while H&E staining demonstrated NLC accumulation in murine AM in vivo with no signs of histopathological/biochemical changes. Bronchoalveolar lavage showed significantly low levels of LDH and total proteins (TP) for LNZ-NLCs highlighting their superior safety. Respirable microparticles embedding LNZ-NLCs ensured excellent aerosolization (MMAD 2 μm, FPF 93%) denoting perfect alveolar deposition. The developed inhalation therapy provided sustained LNZ release, mucus penetrability, potential safety in therapeutic doses, in vitro and in vivo macrophage targetability, and preferential deposition in the deep lung. Overall positive outcomes rely on reduced dose, dosing frequency, and per se superior safety circumventing systemic-associated life-threatening side effects. Graphical abstract.

Nanostructured Lipid Carriers for Delivery of Chemotherapeutics: A Review

The efficacy of current standard chemotherapy is suboptimal due to the poor solubility and short half-lives of chemotherapeutic agents, as well as their high toxicity and lack of specificity which may result in severe side effects, noncompliance and patient inconvenience. The application of nanotechnology has revolutionized the pharmaceutical industry and attracted increasing attention as a significant means for optimizing the delivery of chemotherapeutic agents and enhancing their efficiency and safety profiles. Nanostructured lipid carriers (NLCs) are lipid-based formulations that have been broadly studied as drug delivery systems. They have a solid matrix at room temperature and are considered superior to many other traditional lipid-based nanocarriers such as nanoemulsions, liposomes and solid lipid nanoparticles (SLNs) due to their enhanced physical stability, improved drug loading capacity, and biocompatibility. This review focuses on the latest advances in the use of NLCs as drug delivery systems and their preparation and characterization techniques with special emphasis on their applications as delivery systems for chemotherapeutic agents and different strategies for their use in tumor targeting.

Converting nanosuspension into inhalable and redispersible nanoparticles by combined in-situ thermal gelation and spray drying

While nanoparticulate drugs for deep lung delivery hold promise for particular disease treatments, their size-related physical instability and tendency of being exhaled during breathing remain major challenges to their inhaled formulation development. Here we report a viable method for converting drug nanosuspensions into inhalable, stable and redispersible nano-agglomerates through combined in-situ thermal gelation and spray drying. Itraconazole (ITZ) nanosuspensions were prepared by flash nanoprecipitation, and co-spray dried with two different grades of the gel-forming polymer, methylcellulose (MC M20 and MC M450) as protectants. MC M20 was found superior in protecting ITZ nanoparticles against thermal stress (through nanoparticle entrapment within its gel network structure) during spray drying. In terms of redispersibility, an S_f/S_i ratio (i.e., ratio of nanoparticle sizes after and before spray drying) of unity (1.02 ± 0.03), reflecting full particle size preservation, was achieved by optimizing the suspending medium content and spray drying parameters. Formulation components, nanosuspension concentration and spray drying parameters all showed a significant impact on the aerosol performance of the resulting agglomerates, but an absence of defined trends or correlations. Overall, the MC-protected nano-agglomerates displayed excellent in-vitro aerosol performance with fine particle fractions higher than 50% and mass median aerodynamic diameters within the 2-3 µm range, which are ideal for deep lung delivery.

Nanoparticles fabricated from bulk solid lipids: Preparation, properties, and potential food applications

Unlike conventional emulsions, solid lipids are used to prepare solid lipid nanoparticles (SLNs) with crystalline structures and nanostructured lipid carriers (NLCs) with imperfect crystals or amorphous structures to encapsulate various bioactive compounds significant to food applications. The solid lipid matrix can stabilize particle structures and control release properties of the encapsulated compounds that may not be possible for emulsions with liquid droplets. In this review, common approaches of preparing SLNs and NLCs are first presented, followed by parameters used to study lipid particles, including dimensional, morphological, charge, thermal, and crystalline properties. The structures of SLNs and NLCs with respect to the release mechanisms of encapsulated compounds are discussed in the context of lipid and emulsifier chemistry and preparation conditions. Lastly, possible applications of SLNs and NLCs in food systems are discussed.

Multicompartmental lipid–protein nanohybrids for combined tretinoin/herbal lung cancer therapy

Aim: Multicompartmental lipid–protein nanohybrids (MLPNs) were developed for combined delivery of the anticancer drugs tretinoin (TRE) and genistein (GEN) as synergistic therapy of lung cancer. Materials & methods: The GEN-loaded lipid core was first prepared and then coated with TRE-loaded zein shell via nanoprecipitation. Results: TRE/GEN-MLPNs demonstrated a size of 154.5 nm. In situ ion pair formation between anionic TRE and the cationic stearyl amine improved the drug encapsulation with enhanced stability of MLPNs. TRE/GEN-coloaded MLPNs were more cytotoxic against A549 cancer cells compared with combined free GEN/TRE. In vivo, lung cancer bearing mice treated with TRE/GEN-MLPNs displayed higher apoptotic caspase activation compared with mice-treated free combined GEN/TRE. Conclusion: TRE/GEN-MLPNs might serve as a promising parenteral nanovehicles for lung cancer therapy.

Preparation, Characterization, and Stability Evaluation of Taste-Masking Lacosamide Microparticles

Lacosamide (LCM) is a third-generation antiepileptic drug. Selective action of the drug on voltage-gated sodium channels reduces side effects. Oral administration of LCM shows good pharmacokinetic profile. However, the bitter taste of LCM is a barrier to the development of oral formulations. In this study, we aimed to prepare encapsulated LCM microparticles (MPs) for masking its bitter taste. Encapsulated LCM MPs were prepared with Eudragit^® E100 (E100), a pH-dependent polymer, by spray drying. Three formulations comprising different ratios of LCM and E100 (3:1, 1:1, and 1:3) were prepared. Physicochemical tests showed that LCM was in an amorphous state in the prepared formulations, and they were not miscible. LCM-E100 (1:3) had a rough surface due to surface enrichment of LCM. Increased E100 ratio in LCM-E100 MPs resulted in better taste-making effectiveness: LCM-E100 (1:1) and LCM-E100 (1:3) showed good taste-masking effectiveness, while LCM-E100 (3:1) could not mask the bitter taste of LCM. Dissolution results of the prepared formulations showed good correlation with taste-masking effectiveness. Nevertheless, high E100 ratio reduced the stability of the prepared formulations. Especially the difference in initial dissolution profile observed for LCM-E100 (1:3) indicated rapid reduction in taste-masking effectiveness and surface recrystallization. Therefore, LCM-E100 formulation in the ratio of 1:1 was selected as the best formulation with good taste-masking effectiveness and stability.

Exploring the Nano Spray-Drying Technology as an Innovative Manufacturing Method for Solid Lipid Nanoparticle Dry Powders

To take advantage of solid-state properties, the nano spray-drying (NSD) technique was investigated as an innovative one-step method to produce solid lipid nanoparticles (SLN) in the form of a dry powder starting from a lipid/leucine O/W emulsion. Compritol was chosen as wall-forming lipid. Rapamycin (Rp) was employed as a model drug to be loaded into SLN. Based on an initial screening, Lutrol F68 was chosen as surfactant and high-shear homogenization as an emulsification method. A two-level fractional factorial design and an extended factorial design were employed to determine critical factors and best preparation conditions. Compritol concentration, L-leucine/lipid ratio, and Lutrol F68 concentration resulted critical. Best conditions granted 51% yield, 3.2 μm L-leucine/SLN particle size, and a SLN population around 150 nm. All samples showed the presence of lipid aggregates. Material loss in the emulsification step was found responsible for SLN aggregation and low yield. The almost quantitative Rp loading increased SLN population span. Replacing compritol with cetyl palmitate produced aggregation of dry powders and SLN. Overall, NSD was found a fast method to produce SLN dry powders. More insightful assessment of the emulsification step and lipid property effects will be critical to the optimization of the NSD process. Hypotheses account for direct coupling of high-pressure homogenization with NSD for future successful development of this promising manufacturing method.

Physicochemical characterization of solid lipid nanoparticles comprised of glycerol monostearate and bile salts

Successful applications of solid lipid nanoparticles (SLNs) rely on their physicochemical properties which are mainly governed by their comprising materials (e.g., lipids, emulsifiers) and preparation methods. We have prepared biocompatible solid lipid nanoparticles with glycerol monostearate as lipid and varying combinations of bile salts sodium deoxycholate and sodium cholate (bile salts to lipid ratio 8% w/w) as emulsifiers. The detailed characterization of solid lipid nanoparticles was performed using a combination of light scattering, microscopic, calorimetric, and spectroscopic techniques. It was seen that different compositions of bile salts yield nanoparticles with different sizes. The use of only sodium deoxycholate (8% w/w) produces nanoparticles with average sizes ∼487 nm. The average particle size increases with increasing cholate fraction. A higher average particle size around ∼652 nm is obtained with 8% (w/w) sodium cholate. All the SLNs show good physical stability at room temperature and do not show polymorphic transformation during the storage. In order to study the microenvironments, solid lipid nanoparticles are loaded with an external fluorescent-probe fisetin (probe to lipid ratio 1% w/w). Photophysical properties of fisetin loaded SLNs indicate the micro-heterogenicity inside the nanoparticles.