Solid lipid nanoparticles and nanostructured lipid carriers: A review emphasizing on particle structure and drug release

Improved Local Anesthesia at Inflamed Tissue Using the Association of Articaine and Copaiba Oil in Avocado Butter Nanostructured Lipid Carriers

Unsuccessful anesthesia often occurs under an inflammatory tissue environment, making dentistry treatment extremely painful and challenging. Articaine (ATC) is a local anesthetic used at high (4%) concentrations. Since nanopharmaceutical formulations may improve the pharmacokinetics and pharmacodynamics of drugs, we encapsulated ATC in nanostructured lipid carriers (NLCs) aiming to increase the anesthetic effect on the inflamed tissue. Moreover, the lipid nanoparticles were prepared with natural lipids (copaiba (Copaifera langsdorffii) oil and avocado (Persia gratissima) butter) that added functional activity to the nanosystem. NLC-CO-A particles (~217 nm) showed an amorphous lipid core structure according to DSC and XDR. In an inflammatory pain model induced by λ-carrageenan in rats, NLC-CO-A improved (30%) the anesthetic efficacy and prolonged anesthesia (3 h) in relation to free ATC. In a PGE2-induced pain model, the natural lipid formulation significantly reduced (~20%) the mechanical pain when compared to synthetic lipid NLC. Opioid receptors were involved in the detected analgesia effect since their blockage resulted in pain restoration. The pharmacokinetic evaluation of the inflamed tissue showed that NLC-CO-A decreased tissue ATC elimination rate (ke) by half and doubled ATC’s half-life. These results present NLC-CO-A as an innovative system to break the impasse of anesthesia failure in inflamed tissue by preventing ATC accelerated systemic removal by the inflammatory process and improving anesthesia by its association with copaiba oil.

Optimization of the different phases of the freeze-drying process of solid lipid nanoparticles using experimental designs

In this work, the effect of cryoprotectant type and concentration and freeze-drying process parameters were evaluated to determine an optimal freeze-drying process for celecoxib-loaded solid lipid nanoparticles. Different cryoprotectants were tested at different weight ratios (cryoprotectant:lipid). Trehalose, maltose, and sucrose at a 1:1 wt ratio were selected for further use in optimizing the freeze-drying process through experimental designs to accurately define the freezing, primary, and secondary drying conditions of the freeze-drying process. The optimal freeze-dried solid lipid nanoparticles were subjected to a 6-month stability study at either 4 °C or 25 °C/60% RH, resulting in significant growth when the nanoparticles were stored at 25 °C/60% RH. The best results were obtained with trehalose as a cryoprotectant and storage at 4 °C. Furthermore, the in vitro release data showed a significantly different release profile before and after optimization of the freeze-drying process, suggesting that the optimization of the freeze-drying process affected the quality of the freeze-dried cake. In conclusion, a successful lyophilization process was obtained due to rational cooperation between a good formulation and optimal conditions in the freezing and drying steps. This yielded an acceptable non-collapsed freeze-dried cake with good redispersibility, minimal changes in physicochemical properties, and long-term stability at 4 °C.

Recent Progress of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers as Ocular Drug Delivery Platforms

Sufficient ocular bioavailability is often considered a challenge by the researchers, due to the complex structure of the eye and its protective physiological mechanisms. In addition, the low viscosity of the eye drops and the resulting short ocular residence time further contribute to the observed low drug concentration at the target site. Therefore, various drug delivery platforms are being developed to enhance ocular bioavailability, provide controlled and sustained drug release, reduce the number of applications, and maximize therapy outcomes. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) exhibit all these benefits, in addition to being biocompatible, biodegradable, and susceptible to sterilization and scale-up. Furthermore, their successive surface modification contributes to prolonged ocular residence time (by adding cationic compounds), enhanced penetration, and improved performance. The review highlights the salient characteristics of SLNs and NLCs concerning ocular drug delivery, and updates the research progress in this area.

Influence of the Triglyceride Composition, Surfactant Concentration and Time–Temperature Conditions on the Particle Morphology in Dispersions

Many applications for crystalline triglyceride-in-water dispersions exist in the life sciences and pharmaceutical industries. The main dispersion structures influencing product properties are the particle morphology and size distribution. These can be set by the formulation and process parameters, but temperature fluctuations may alter them afterwards. As the dispersed phase often consists of complex fats, there are many formulation variables influencing these product properties. In this study, we aimed to gain a better understanding of the influence of the dispersed-phase composition on the crystallization and melting behavior of these systems. We found that different particle morphologies can be obtained by varying the dispersed-phase composition. Droplets smaller than 1 µm were obtained after melting due to self-emulsification (SE), but these changes and coalescence events were only partly influenced by the melting range of the fat. With increasing surfactant concentration, the SE tendency increased. The smallest x50,3 of 3 µm was obtained with a surfactant concentration of 0.5 wt%. We attributed this to different mechanisms leading to the droplets’ breakup during melting, which we observed via thermo-optical microscopy. In addition, SE and coalescence are a function of the cooling and heating profiles. With slow heating (0.5 K/min), both phenomena are more pronounced, as the particles have more time to undergo the required mechanisms.

Functional nano-systems for transdermal drug delivery and skin therapy

Transdermal drug delivery is one of the least intrusive and patient-friendly ways for therapeutic agent administration. Recently, functional nano-systems have been demonstrated as one of the most promising strategies to treat skin diseases by improving drug penetration across the skin barrier and achieving therapeutically effective drug concentrations in the target cutaneous tissues. Here, a brief review of functional nano-systems for promoting transdermal drug delivery is presented. The fundamentals of transdermal delivery, including skin biology and penetration routes, are introduced. The characteristics of functional nano-systems for facilitating transdermal drug delivery are elucidated. Moreover, the fabrication of various types of functional transdermal nano-systems is systematically presented. Multiple techniques for evaluating the transdermal capacities of nano-systems are illustrated. Finally, the advances in the applications of functional transdermal nano-systems for treating different skin diseases are summarized.

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.

An evolving perspective on novel modified release drug delivery systems for inhalational therapy

INTRODUCTION

Drugs delivered via the lungs are predominantly used to treat various respiratory disorders, including asthma, chronic obstructive pulmonary diseases, respiratory tract infections and lung cancers, and pulmonary vascular diseases such as pulmonary hypertension. To treat respiratory diseases, targeted, modified or controlled release inhalation formulations are desirable for improved patient compliance and superior therapeutic outcome.

AREAS COVERED

This review summarizes the important factors that have an impact on the inhalable modified release formulation approaches with a focus toward various formulation strategies, including dissolution rate-controlled systems, drug complexes, site-specific delivery, drug-polymer conjugates, and drug-polymer matrix systems, lipid matrix particles, nanosystems, and formulations that can bypass clearance via mucociliary system and alveolar macrophages.

EXPERT OPINION

Inhaled modified release formulations can potentially reduce dosing frequency by extending drug's residence time in the lungs. However, inhalable modified or controlled release drug delivery systems remain unexplored and underdeveloped from the commercialization perspective. This review paper addresses the current state-of-the-art of inhaled controlled release formulations, elaborates on the avenues for developing newer technologies for formulating various drugs with tailored release profiles after inhalational delivery and explains the challenges associated with translational feasibility of modified release inhalable formulations.

Advances in Lipid-Based Codelivery Systems for Cancer and Inflammatory Diseases

Combination therapy targeting multiple therapeutic targets is a favorable strategy to achieve better therapeutic outcomes in cancer and inflammatory diseases. Codelivery is a subfield of drug delivery that aims to achieve combined delivery of diverse therapeutic cargoes within the same delivery system, thereby ensuring delivery to the same site and providing an opportunity to tailor the release kinetics as desired. Among the wide range of materials being investigated in the design of codelivery systems, lipids have stood out on account of their low toxicity, biocompatibility, and ease of formulation scale-up. This review highlights the advances of the last decade in lipid-based codelivery systems focusing on the codelivery of drug-drug, drug-nucleic acid, nucleic acid-nucleic acid, and protein therapeutic-based combinations for targeted therapy in cancer and inflammatory diseases.

Design of functional nanoparticles by microfluidic platforms as advanced drug delivery systems for cancer therapy

Nanoparticle systems are functional carriers that can be used in the cancer therapy field for the delivery of a variety of hydrophobic and/or hydrophilic drugs. Recently, the advent of microfluidic platforms represents an advanced approach to the development of new nanoparticle-based drug delivery systems. Particularly, microfluidics can simplify the design of new nanoparticle-based systems with tunable physicochemical properties such as size, size distribution and morphology, ensuring high batch-to-batch reproducibility and consequently, an enhanced therapeutic effect in vitro and in vivo. In this perspective, we present accurate state-of-the-art microfluidic platforms focusing on the fabrication of polymer-based, lipid-based, lipid/polymer-based, inorganic-based and metal-based nanoparticles for biomedical applications.

Study of Candelilla Wax Concentrations on the Physical Properties of Edible Nanocoatings as a Function of Support Polysaccharides

Solid lipid nanoparticles (SLN) based on candelilla wax were prepared using the hot homogenization technique. The resulting suspension had monomodal behavior with a particle size of 809-885 nm; polydispersity index < 0.31, and zeta potential of -3.5 mV 5 weeks after monitoring. The films were prepared with SLN concentrations of 20 and 60 g/L, each with a plasticizer concentration of 10 and 30 g/L; the polysaccharide stabilizers used were either xanthan gum (XG) or carboxymethyl cellulose (CMC) at 3 g/L. The effects of temperature, film composition, and relative humidity on the microstructural, thermal, mechanical, and optical properties, as well as the water vapor barrier, were evaluated. Higher amounts of SLN and plasticizer gave the films greater strength and flexibility due to the influence of temperature and relative humidity. The water vapor permeability (WVP) was lower when 60 g/L of SLN was added to the films. The arrangement of the SLN in the polymeric networks showed changes in the distribution as a function of the concentrations of the SLN and plasticizer. The total color difference (ΔE) was greater when the content of the SLN was increased, with values of 3.34-7.93. Thermal analysis showed an increase in the melting temperature when a higher SLN content was used, whereas a higher plasticizer content reduced it. Edible films with the most appropriate physical properties for the packaging, shelf-life extension, and improved quality conservation of fresh foods were those made with 20 g/L of SLN, 30 g/L of glycerol, and 3 g/L of XG.

Formulation Approaches to Crystalline Status Modification for Carotenoids: Impacts on Dissolution, Stability, Bioavailability, and Bioactivities

Carotenoids, including carotenes and xanthophylls, have been identified as bioactive ingredients in foods and are considered to possess health-promoting effects. From a biopharmaceutical perspective, several physicochemical characteristics, such as scanty water solubility, restricted dissolution, and susceptibility to oxidation may influence their oral bioavailability and eventually, their effectiveness. In this review, we have summarized various formulation approaches that deal with the modification of crystalline status for carotenoids, which may improve their physicochemical properties, oral absorption, and biological effects. The mechanisms involving crystalline alteration and the typical methods for examining crystalline states in the pharmaceutical field have been included, and representative formulation approaches are introduced to unriddle the mechanisms and effects more clearly.

Solid Lipid Nanoparticles: Peculiar Strategy to Deliver Bio-Proactive Molecules

BACKGROUND

Novel Drug Delivery Systems (NDDS) provide numerous benefits compared to conventional dosage forms. Poor aqueous solubility, low bioavailability, frequent dosing, and particular hydrophilic lipophilic character of the drug are the biological factors associated with the traditional systems leading to the development of SLNs.

OBJECTIVE

For improving the solubility profile, enhancing the bioavailability, and attaining the best possible therapeutic effect of lipid inclined or aqueous inclined drug, formulating solid lipid nanoparticles is the best choice.

METHODS

Solid Lipid Nanoparticles (SLNs) have been projected as a colloidal carrier system with a size of 50-1,000 nm, collectively combining the benefits of other colloidal systems like liposomes, emulsions, etc., for delivering the drug at the target site. High absorption, high stability, and efficient drug packing enhance the pharmacokinetic and pharmacodynamic properties of the packed drug.

RESULT

Solid Lipid Nanoparticles can be developed in different dosage forms and administered via routes such as nasal, rectal, oral, topical, vaginal, ocular, and parenteral. They have higher physicochemical stability and the batch size can be easily scaled up at a low cost. Lipophilic as well as hydrophilic drugs can be easily incorporated into solid lipid nanoparticles.

CONCLUSION

In this manuscript, the authors have reviewed different aspects of solid lipid nanoparticles, major principles behind mechanism methods, recent patents, applications, and therapeutic potentials of solid lipid nanoparticles.

Docetaxel Loaded in Copaiba Oil-Nanostructured Lipid Carriers as a Promising DDS for Breast Cancer Treatment

Breast cancer is the neoplasia of highest incidence in women worldwide. Docetaxel (DTX), a taxoid used to treat breast cancer, is a BCS-class-IV compound (low oral bioavailability, solubility and intestinal permeability). Nanotechnological strategies can improve chemotherapy effectiveness by promoting sustained release and reducing systemic toxicity. Nanostructured lipid carriers (NLC) encapsulate hydrophobic drugs in their blend-of-lipids matrix, and imperfections prevent drug expulsion during storage. This work describes the preparation, by design of experiments (2³ factorial design) of a novel NLC formulation containing copaiba oil (CO) as a functional excipient. The optimized formulation (NLC_DTX) showed approximately 100% DTX encapsulation efficiency and was characterized by different techniques (DLS, NTA, TEM/FE-SEM, DSC and XRD) and was stable for 12 months of storage, at 25 °C. Incorporation into the NLC prolonged drug release for 54 h, compared to commercial DTX (10 h). In vitro cytotoxicity tests revealed the antiproliferative effect of CO and NLC_DTX, by reducing the cell viability of breast cancer (4T1/MCF-7) and healthy (NIH-3T3) cells more than commercial DTX. NLC_DTX thus emerges as a promising drug delivery system of remarkable anticancer effect, (strengthened by CO) and sustained release that, in clinics, may decrease systemic toxicity at lower DTX doses.

How Charge, Size and Protein Corona Modulate the Specific Activity of Nanostructured Lipid Carriers (NLC) against Helicobacter pylori

The major risk factor associated with the development of gastric cancer is chronic infection with Helicobacter pylori. The available treatments, based on a cocktail of antibiotics, fail in up to 40% of patients and disrupt their gut microbiota. The potential of blank nanostructured lipid carriers (NLC) for H. pylori eradication was previously demonstrated by us. However, the effect of NLC charge, size and protein corona on H. pylori-specific bactericidal activity herein studied was unknown at that time. All developed NLC formulations proved bactericidal against H. pylori. Although cationic NLC had 10-fold higher bactericidal activity than anionic NLC, they lacked specificity, since Lactobacillus acidophilus was also affected. Anionic NLC achieved complete clearance in both H. pylori morphologies (rod- and coccoid-shape) by inducing alterations in bacteria membranes and the cytoplasm, as visualized by transmission electron microscopy (TEM). The presence of an NLC protein corona, composed of 93% albumin, was confirmed by mass spectrometry. This protein corona delayed the bactericidal activity of anionic NLC against H. pylori and hindered NLC activity against Escherichia coli. Overall, these results sustain the use of NLC as a promising antibiotic-free strategy targeting H. pylori.

Solid lipid nanoparticles: a promising tool for insulin delivery

INTRODUCTION

Insulin plays a critical role in metabolism modulation including carbohydrate, lipid, and protein metabolism. There is room to improve insulin delivery but optimizing the best carrier remains challenging. Traditional and conventional approaches for insulin delivery do not emulate the normal fate of insulin release in the body. Despite extensive research attempts to overcome this and other challenges, the goal of achieving optimal insulin delivery that emulates the natural system remains unresolved.

AREAS COVERED

Solid Lipid Nanoparticles (SLNs) may provide a solution, because they are nontoxic, biocompatible, and straightforward to formulate thus providing a promising platform for achieving targeted and controlled delivery of various therapeutic agents. This review aims to provide an overview on the suitability and application of SLNs for insulin delivery. A special emphasis is placed on the biopharmaceutical aspects of insulin loaded SLNs which have not been explored in detail to date.

EXPERT OPINION

SLNs have proven to be safe and versatile drug delivery systems suitable for insulin delivery and capable of improving the efficacy and pharmacokinetic profile of encapsulated insulin. There is still some work to be done to fully explore SLNs' true potential as drug delivery and specifically insulin delivery vehicles suitable for clinical use.

Glioma diagnosis and therapy: Current challenges and nanomaterial-based solutions

Glioma is often referred to as one of the most dreadful central nervous system (CNS)-specific tumors with rapidly-proliferating cancerous glial cells, accounting for nearly half of the brain tumors at an annual incidence rate of 30-80 per a million population. Although glioma treatment remains a significant challenge for researchers and clinicians, the rapid development of nanomedicine provides tremendous opportunities for long-term glioma therapy. However, several obstacles impede the development of novel therapeutics, such as the very tight blood-brain barrier (BBB), undesirable hypoxia, and complex tumor microenvironment (TME). Several efforts have been dedicated to exploring various nanoformulations for improving BBB permeation and precise tumor ablation to address these challenges. Initially, this article briefly introduces glioma classification and various pathogenic factors. Further, currently available therapeutic approaches are illustrated in detail, including traditional chemotherapy, radiotherapy, and surgical practices. Then, different innovative treatment strategies, such as tumor-treating fields, gene therapy, immunotherapy, and phototherapy, are emphasized. In conclusion, we summarize the article with interesting perspectives, providing suggestions for future glioma diagnosis and therapy improvement.

Solid Lipid Nanoparticles Based on Monosubstituted Pillar[5]arenes: Chemoselective Synthesis of Macrocycles and Their Supramolecular Self-Assembly

Novel monosubstituted pillar[5]arenes with one or two terminal carboxyl groups were synthesized by the reaction of succinic anhydride with pillar[5]arene derivative containing a diethylenetriamine function. The ability for non-covalent self-assembly in chloroform, dimethyl sulfoxide, as well as in tetrahydrofuran-water system was studied. The ability of the synthesized macrocycles to form different types of associates depending on the substituent nature was established. The formation of stable particles with average diameter of 192 nm in chloroform and of 439 nm in DMSO was shown for pillar[5]arene containing two carboxyl fragments. Solid lipid nanoparticles (SLN) based on monosubstituted pillar[5]arenes were synthesized by nanoprecipitation in THF-water system. Minor changes in the structure of the macrocycle substituent can dramatically influence the stability and shape of SLN (spherical and rod-like structures) accordingly to DLS and TEM. The presence of two carboxyl groups in the macrocycle substituent leads to the formation of stable spherical SLN with an average hydrodynamic diameter of 364-454 nm. Rod-like structures are formed by pillar[5]arene containing one carboxyl fragment, which diameter is about of 50-80 nm and length of 700-1000 nm. The synthesized stable SLN open up great prospects for their use as drug storage systems.

Local Delivery of Azithromycin Nanoformulation Attenuated Acute Lung Injury in Mice

Humanity has suffered from the coronavirus disease 2019 (COVID-19) pandemic over the past two years, which has left behind millions of deaths. Azithromycin (AZ), an antibiotic used for the treatment of several bacterial infections, has shown antiviral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as well as against the dengue, Zika, Ebola, and influenza viruses. Additionally, AZ has shown beneficial effects in non-infective diseases such as cystic fibrosis and bronchiectasis. However, the systemic use of AZ in several diseases showed low efficacy and potential cardiac toxicity. The application of nanotechnology to formulate a lung delivery system of AZ could prove to be one of the solutions to overcome these drawbacks. Therefore, we aimed to evaluate the attenuation of acute lung injury in mice via the local delivery of an AZ nanoformulation. The hot emulsification-ultrasonication method was used to prepare nanostructured lipid carrier of AZ (AZ-NLC) pulmonary delivery systems. The developed formulation was evaluated and characterized in vitro and in vivo. The efficacy of the prepared formulation was tested in the bleomycin (BLM) -mice model for acute lung injury. AZ-NLC was given by the intratracheal (IT) route for 6 days at a dose of about one-eighth oral dose of AZ suspension. Samples of lung tissues were taken at the end of the experiment for immunological and histological assessments. AZ-NLC showed an average particle size of 453 nm, polydispersity index of 0.228 ± 0.07, zeta potential of -30 ± 0.21 mV, and a sustained release pattern after the initial 50% drug release within the first 2 h. BLM successfully induced a marked increase in pro-inflammatory markers and also induced histological changes in pulmonary tissues. All these alterations were significantly reversed by the concomitant administration of AZ-NLC (IT). Pulmonary delivery of AZ-NLC offered delivery of the drug locally to lung tissues. Its attenuation of lung tissue inflammation and histological injury induced by bleomycin was likely through the downregulation of the p53 gene and the modulation of Bcl-2 expression. This novel strategy could eventually improve the effectiveness and diminish the adverse drug reactions of AZ. Lung delivery could be a promising treatment for acute lung injury regardless of its cause. However, further work is needed to explore the stability of the formulation, its pharmacokinetics, and its safety.

Photodynamic therapy-mediated hypericin-loaded nanostructured lipid carriers against vulvovaginal candidiasis

INTRODUCTION AND AIM

The indiscriminate use and adverse effects of the main conventional antifungal agents compromise the effectiveness of treating vulvovaginal candidiasis (VVC), mainly caused by the species Candida albicans. This study evaluated the effectiveness of photodynamic therapy (PDT) and the in vitro and in vivo anti-candida potential of the hypericin (HYP)-loaded nanostructured lipid carriers (NLC).

MATERIALS AND METHODS

Empty NLC and NLC-HYP were characterized by the dynamic light scattering technique and transmission electron microscopy to evaluate the average particle size distribution and its morphologies. The in vitro inhibition photodynamic effect of the systems was tested to reduce the planktonic viability of C. albicans. The therapeutic assay photodynamic of the systems was performed to treat VVC in mice.

RESULTS

Empty NLC and NLC-HYP presented values of average hydrodynamic diameter, polydispersity index, and ζ-potential from 136 to 133 nm, 0.16 to 0.22, and -18 to -30 mV, respectively, on day 30. Microscopically, the systems showed spherical morphologies and nanoscale particles. Furthermore, in the in vitro inhibition assay, the treatment of PDT with NLC-HYP (NLC-HYP+) showed a significant reduction of the C. albicans planktonic viability compared to YNB negative control after 5 min of LED light irradiation. In the in vivo therapeutic assay, the antifungal group (vaginal antifungal cream) and NLC-HYP+ evaluated in the dark and by PDT, respectively, had a significant log₁₀ reduction in fungal burden compared to the infected group on day 8 of the VVC treatment.

CONCLUSION

Due to the in vitro and in vivo anti-candida potential, PDT-mediated systems can be an effective strategy in VVC therapy.

Recent Advances in the Development of Lipid-, Metal-, Carbon-, and Polymer-Based Nanomaterials for Antibacterial Applications

Infections caused by multidrug-resistant (MDR) bacteria are becoming a serious threat to public health worldwide. With an ever-reducing pipeline of last-resort drugs further complicating the current dire situation arising due to antibiotic resistance, there has never been a greater urgency to attempt to discover potential new antibiotics. The use of nanotechnology, encompassing a broad range of organic and inorganic nanomaterials, offers promising solutions. Organic nanomaterials, including lipid-, polymer-, and carbon-based nanomaterials, have inherent antibacterial activity or can act as nanocarriers in delivering antibacterial agents. Nanocarriers, owing to the protection and enhanced bioavailability of the encapsulated drugs, have the ability to enable an increased concentration of a drug to be delivered to an infected site and reduce the associated toxicity elsewhere. On the other hand, inorganic metal-based nanomaterials exhibit multivalent antibacterial mechanisms that combat MDR bacteria effectively and reduce the occurrence of bacterial resistance. These nanomaterials have great potential for the prevention and treatment of MDR bacterial infection. Recent advances in the field of nanotechnology are enabling researchers to utilize nanomaterial building blocks in intriguing ways to create multi-functional nanocomposite materials. These nanocomposite materials, formed by lipid-, polymer-, carbon-, and metal-based nanomaterial building blocks, have opened a new avenue for researchers due to the unprecedented physiochemical properties and enhanced antibacterial activities being observed when compared to their mono-constituent parts. This review covers the latest advances of nanotechnologies used in the design and development of nano- and nanocomposite materials to fight MDR bacteria with different purposes. Our aim is to discuss and summarize these recently established nanomaterials and the respective nanocomposites, their current application, and challenges for use in applications treating MDR bacteria. In addition, we discuss the prospects for antimicrobial nanomaterials and look forward to further develop these materials, emphasizing their potential for clinical translation.

Development of New Natural Lipid-Based Nanoparticles Loaded with Aluminum-Phthalocyanine for Photodynamic Therapy against Melanoma

Photodynamic therapy (PDT) mediated by photosensitizers loaded in nanostructures as solid lipid nanoparticles has been pinpointed as an effective and safe treatment against different skin cancers. Amazon butters have an interesting lipid composition when it comes to forming solid lipid nanoparticles (SLN). In the present report, a new third-generation photosensitizing system consisting of aluminum-phthalocyanine associated with Amazon butter-based solid lipid nanoparticles (SLN-AlPc) is described. The SLN was developed using murumuru butter, and a monodisperse population of nanodroplets with a hydrodynamic diameter of approximately 40 nm was obtained. The study of the permeation of these AlPc did not permeate the analyzed skin, but when incorporated into the system, SLN-AlPc allowed permeation of almost 100% with 8 h of contact. It must be emphasized that SLN-AlPc was efficient for carrying aluminum-phthalocyanine photosensitizers and exhibited no toxicity in the dark. Photoactivated SLN-AlPc exhibited a 50% cytotoxicity concentration (IC₅₀) of 19.62 nM when applied to B16-F10 monolayers, and the type of death caused by the treatment was apoptosis. The exposed phospholipid phosphatidylserine was identified, and the treatment triggered a high expression of Caspase 3. A stable Amazon butter-based SLN-AlPc formulation was developed, which exhibits strong in vitro photodynamic activity on melanoma cells.

An Overview of Herbal-Based Antidiabetic Drug Delivery Systems: Focus on Lipid- and Inorganic-Based Nanoformulations

Diabetes is a metabolic pathology with chronic high blood glucose levels that occurs when the pancreas does not produce enough insulin or the body does not properly use the insulin it produces. Diabetes management is a puzzle and focuses on a healthy lifestyle, physical exercise, and medication. Thus far, the condition remains incurable; management just helps to control it. Its medical treatment is expensive and is to be followed for the long term, which is why people, especially from low-income countries, resort to herbal medicines. However, many active compounds isolated from plants (phytocompounds) are poorly bioavailable due to their low solubility, low permeability, or rapid elimination. To overcome these impediments and to alleviate the cost burden on disadvantaged populations, plant nanomedicines are being studied. Nanoparticulate formulations containing antidiabetic plant extracts or phytocompounds have shown promising results. We herein aimed to provide an overview of the use of lipid- and inorganic-based nanoparticulate delivery systems with plant extracts or phytocompounds for the treatment of diabetes while highlighting their advantages and limitations for clinical application. The findings from the reviewed works showed that these nanoparticulate formulations resulted in high antidiabetic activity at low doses compared to the corresponding plant extracts or phytocompounds alone. Moreover, it was shown that nanoparticulate systems address the poor bioavailability of herbal medicines, but the lack of enough preclinical and clinical pharmacokinetic and/or pharmacodynamic trials still delays their use in diabetic patients.

Lipid nanoparticles strategies to modify pharmacokinetics of central nervous system targeting drugs: Crossing or circumventing the blood-brain barrier (BBB) to manage neurological disorders

The main limitation to the success of central nervous system (CNS) therapies lies in the difficulty for drugs to cross the blood-brain barrier (BBB) and reach the brain. Regarding its structure and enzymatic complexity, crossing the BBB is a challenge, although several alternatives have been identified. For instance, the use of drugs encapsulated in lipid nanoparticles has been described as one of the most efficient approaches to bypass the BBB, as they allow the passage of drugs through this barrier, improving brain bioavailability. In particular, solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) have been a focus of research related to drug delivery to the brain. These systems provide protection of lipophilic drugs, improved delivery and bioavailability, having a major impact on treatments outcomes. In addition, the use of lipid nanoparticles administered via routes that transport drugs directly into the brain seems a promising solution to avoid the difficulties in crossing the BBB. For instance, the nose-to-brain route has gained considerable interest, as it has shown efficacy in 3D human nasal models and in animal models. This review addresses the state of the art on the use of lipid nanoparticles to modify the pharmacokinetics of drugs employed in the management of neurological disorders. A description of the structural components of the BBB, the role of the neurovascular unit and limitations for drugs to entry into the CNS is first addressed, along with the developments to increase drug delivery to the brain, with a special focus on lipid nanoparticles. In addition, the obstacle of BBB complexity in the creation of new effective drugs for the treatment of the most prevalent neurological disorders is also addressed. Finally, the proposed strategies for lipid nanoparticles to reach the CNS, crossing or circumventing the BBB, are described. Although promising results have been reported, especially with the nose-to-brain route, they are still ongoing to assess its real efficacy in vivo in the management of neurological disorders.

Preparation, Characterization and Pharmacokinetics of Tolfenamic Acid-Loaded Solid Lipid Nanoparticles

The clinical use of nonsteroidal anti-inflammatory drugs is limited by their poor water solubility, unstable absorption, and low bioavailability. Solid lipid nanoparticles (SLNs) exhibit high biocompatibility and the ability to improve the bioavailability of drugs with low water solubility. Therefore, in this study, a tolfenamic acid solid lipid nanoparticle (TA-SLN) suspension was prepared by a hot melt–emulsification ultrasonication method to improve the sustained release and bioavailability of TA. The encapsulation efficiency (EE), loading capacity (LC), particle size, polydispersity index (PDI), and zeta potential of the TA-SLN suspension were 82.50 ± 0.63%, 25.13 ± 0.28%, 492 ± 6.51 nm, 0.309 ± 0.02 and −21.7 ± 0.51 mV, respectively. The TA-SLN suspension was characterized by dynamic light scattering (DLS), fluorescence microscopy (FM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared (FT-IR) spectroscopy. The TA-SLN suspension showed improved sustained drug release in vitro compared with the commercially available TA injection. After intramuscular administration to pigs (4 mg/kg), the TA-SLN suspension displayed increases in the pharmacokinetic parameters T_max, T_1/2, and MRT_0–∞ by 4.39-, 3.78-, and 3.78-fold, respectively, compared with TA injection, and showed a relative bioavailability of 185.33%. Thus, this prepared solid lipid nanosuspension is a promising new formulation.

Nanoparticle-Based Inhalation Therapy for Pulmonary Diseases

The lung is exposed to various pollutants and is the primary site for the onset of various diseases, including infections, allergies, and cancers. One possible treatment approach for such pulmonary diseases involves direct administration of therapeutics to the lung so as to maintain the topical concentration of the drug. Particles with nanoscale diameters tend to reach the pulmonary region. Nanoparticles (NPs) have garnered significant interest for applications in biomedical and pharmaceutical industries because of their unique physicochemical properties and biological activities. In this article, we describe the biological and pharmacological activities of NPs as well as summarize their potential in the formulation of drugs employed to treat pulmonary diseases. Recent advances in the use of NPs in inhalation chemotherapy for the treatment of lung diseases have also been highlighted.

Nanostructured Lipid Carriers Loaded with Dexamethasone Prevent Inflammatory Responses in Primary Non-Parenchymal Liver Cells

Liver inflammation represents a major clinical problem in a wide range of pathologies. Among the strategies to prevent liver failure, dexamethasone (DXM) has been widely used to suppress inflammatory responses. The use of nanocarriers for encapsulation and sustained release of glucocorticoids to liver cells could provide a solution to prevent severe side effects associated with systemic delivery as the conventional treatment regime. Here we describe a nanostructured lipid carrier developed to efficiently encapsulate and release DXM. This nano-formulation proved to be stable over time, did not interact in vitro with plasma opsonins, and was well tolerated by primary non-parenchymal liver cells (NPCs). Released DXM preserved its pharmacological activity, as evidenced by inducing robust anti-inflammatory responses in NPCs. Taken together, nanostructured lipid carriers may constitute a reliable platform for the delivery of DXM to treat pathologies associated with chronic liver inflammation.

Enzymatic Active Release of Violacein Present in Nanostructured Lipid Carrier by Lipase Encapsulated in 3D-Bioprinted Chitosan-Hydroxypropyl Methylcellulose Matrix With Anticancer Activity

Violacein (Viol) is a bacterial purple water-insoluble pigment synthesized by Chromobacterium violaceum and other microorganisms that display many beneficial therapeutic properties including anticancer activity. Viol was produced, purified in our laboratory, and encapsulated in a nanostructured lipid carrier (NLC). The NLC is composed of the solid lipid myristyl myristate, an oily lipid mixture composed of capric and caprylic acids, and the surfactant poloxamer P188. Dormant lipase from Rhizomucor miehei was incorporated into the NLC-Viol to develop an active release system. The NLC particle size determined by dynamic light scattering brings around 150 nm particle size and ζ≈ −9.0 mV with or without lipase, but the incorporation of lipase increase the PdI from 0.241 to 0.319 (≈32%). For scaffold development, a 2.5 hydroxypropyl methylcellulose/chitosan ratio was obtained after optimization of a composite for extrusion in a 3D-bioprinter developed and constructed in our laboratory. Final Viol encapsulation efficiency in the printings was over 90%. Kinetic release of the biodye at pH = 7.4 from the mesh containing NLC-lipase showed roughly 20% Viol fast release than without the enzyme. However, both Viol kinetic releases displayed similar profiles at pH = 5.0, where the lipase is inactive. The kinetic release of Viol from the NLC-matrices was modeled and the best correlation was found with the Korsmeyer-Peppas model (R2 = 0.95) with n &lt; 0.5 suggesting a Fickian release of Viol from the matrices. Scanning Electron Microscope (SEM) images of the NLC-meshes showed significant differences before and after Viol’s release. Also, the presence of lipase dramatically increased the gaps in the interchain mesh. XRD and Fourier Transform Infrared (FTIR) analyses of the NLC-meshes showed a decrease in the crystalline structure of the composites with the incorporation of the NLC, and the decrease of myristyl myristate in the mesh can be attributed to the lipase activity. TGA profiles of the NLC-meshes showed high thermal stability than the individual components. Cytotoxic studies in A549 and HCT-116 cancer cell lines revealed high anticancer activity of the matrix mediated by mucoadhesive chitosan, plus the biological synergistic activities of violacein and lipase.

Advances and future perspectives in epithelial drug delivery

Epithelial surfaces protect exposed tissues in the body against intrusion of foreign materials, including xenobiotics, pollen and microbiota. The relative permeability of the various epithelia reflects their extent of exposure to the external environment and is in the ranking: intestinal≈ nasal ≥ bronchial ≥ tracheal > vaginal ≥ rectal > blood-perilymph barrier (otic), corneal > buccal > skin. Each epithelium also varies in their morphology, biochemistry, physiology, immunology and external fluid in line with their function. Each epithelium is also used as drug delivery sites to treat local conditions and, in some cases, for systemic delivery. The associated delivery systems have had to evolve to enable the delivery of larger drugs and biologicals, such as peptides, proteins, antibodies and biologicals and now include a range of physical, chemical, electrical, light, sound and other enhancement technologies. In addition, the quality-by-design approach to product regulation and the growth of generic products have also fostered advancement in epithelial drug delivery systems.

Characterization and Interaction with Biomembrane Model of Benzo[k,l]xanthene Lignan Loaded Solid Lipid Nanoparticles

Benzo[k,l]xanthene lignans are a group of rare natural products belonging to the class of polyphenols with promising biological activities and are studied as potential chemotherapeutic agents. The lipophilic character of a xanthene core makes these molecules difficult to be used in an aqueous medium, limiting their employment in studies for pharmaceutical applications. To overcome this problem, a drug-delivery system which is able to improve the stability and bioavailability of the compound can be used. In this study, a bioactive benzoxanthene lignan (BXL) has been included in SLN. Unloaded and BXL-loaded SLN have been prepared using the Phase Inversion Temperature method and characterized in terms of size, zeta potential, entrapment efficiency and stability. Differential scanning calorimetry was used to evaluate the thermotropic behavior and ability of SLN to act as carriers for BXL. A biomembrane model, represented by multilamellar vesicles, was used to simulate the interaction of the SLN with the cellular membrane. Unloaded and loaded SLN were incubated with the MLV, and their interactions were evaluated through variations in their calorimetric curves. The results obtained suggest that SLN could be used as a delivery system for BXL.

Investigation of Eutectic Mixtures of Fatty Acids as a Novel Construct for Temperature-Responsive Drug Delivery

Background

Most of the traditional nanocarriers of cancer therapeutic moieties present dose-related toxicities due to the uptake of chemotherapeutic agents in normal body cells. The severe life-threatening effects of systemic chemotherapy are well documented. Doxorubicin, DOX is the most effective antineoplastic agent but with the least specific action that is responsible for severe cardiotoxicity and myelosuppression that necessitates careful monitoring while administering. Stimuli-sensitive/intelligent drug delivery systems, specifically those utilizing temperature as an external stimulus to activate the release of encapsulated drugs, have become a subject of recent research. Thus, it would be ideal to have a nanocarrier comprising safe excipients and controllable drug release capacity to deliver the drug at a particular site to minimize unwanted and toxic effects of chemotherapeutics. We have developed a simple temperature-responsive nanocarrier based on eutectic mixture of fatty acids. This study aimed to develop, physicochemically characterize and investigate the biological safety of eutectic mixture of fatty acids as a novel construct for temperature-responsive drug release potential.

Methods

We have developed phase change material, PCM, based on a series of eutectic mixtures of fatty acids due to their unique and attractive physicochemical characteristics such as safety, stability, cost-effectiveness, and ease of availability. The reversible solid-liquid phase transition of PCM is responsible to hold firm or actively release the encapsulated drug. The eutectic mixtures of fatty acids (stearic acid and myristic acid) along with liquid lipid (oleic acid) were prepared to exhibit a tunable thermoresponsive platform. Doxorubicin-loaded lipid nanocarriers were successfully developed with combined hot melt encapsulation (HME) and sonication method and characterized to achieve enhanced permeability and retention (EPR) effect-based solid tumor targeting in response to exogenous temperature stimulus. The cytotoxicity against melanoma cell lines and in vivo safety studies in albino rats was also carried out.

Results

Doxorubicin-loaded lipid nanocarriers have a narrow size distribution (94.59-219.3 nm), and a PDI (0.160-0.479) as demonstrated by photon correlation microscopy and excellent colloidal stability (Z.P value: -22.7 to -32.0) was developed. Transmission electron microscopy revealed their spherical morphology and characteristics of a monodispersed system. A biphasic drug release pattern with a triggered drug release at 41°C and 43°C and a sustained drug release was observed at 37°C. The thermoresponsive cytotoxic potential was demonstrated in B16F10 cancer cell lines. Hemolysis assay and acute toxicity studies with drug-free and doxorubicin lipid nanocarrier formulations provided evidence for their non-toxic nature.

Conclusion

We have successfully developed a temperature-responsive tunable platform with excellent biocompatibility and intelligent drug release potential. The formulation components being from natural sources present superior characteristics in terms of cost, compatibility with normal body cells, and adaptability to preparation methods. The reported preparation method is adapted to avoid complex chemical processes and the use of organic solvents. The lipid nanocarriers with tunable thermoresponsive characteristics are promising biocompatible drug delivery systems for improved localized delivery of chemotherapeutic agents.

Nanomedicine as a magic bullet for combating lymphoma

Hematological malignancy like lymphoma originates in lymph tissues and has a propensity to spread across other organs. Managing such tumors is challenging as conventional strategies like surgery and local treatment are not plausible options and there are high chances of relapse. The advent of novel targeted therapies and antibody-mediated treatments has proven revolutionary in the management of these tumors. Although these therapies have an added advantage of specificity in comparison to the traditional chemotherapy approach, such treatment alternatives suffer from the occurrence of drug resistance and dose-related toxicities. In past decades, nanomedicine has emerged as an excellent surrogate to increase the bioavailability of therapeutic moieties along with a reduction in toxicities of highly cytotoxic drugs. Nanotherapeutics achieve targeted delivery of the therapeutic agents into the malignant cells and also have the ability to carry genes and therapeutic proteins to the desired sites. Furthermore, nanomedicine has an edge in rendering personalized medicine as one type of lymphoma is pathologically different from others. In this review, we have highlighted various applications of nanotechnology-based delivery systems based on lipidic, polymeric and inorganic nanomaterials that address different targets for effectively tackling lymphomas. Moreover, we have discussed recent advances and therapies available exclusively for managing this malignancy.

An updated review on properties, nanodelivery systems, and analytical methods for the determination of 5-fluorouracil in pharmaceutical and biological samples

Abstract:

5-Fluorouracil (5-FU) is an antimetabolite drug used for over 70 years as first-line chemotherapy to treat various types of cancer, such as head, neck, breast and colorectal cancer. 5-FU acts mainly by inhibiting thymidylate synthase, thereby interfering with deoxyribonucleic acid (DNA) replication or by 5-FU incorporating into DNA, causing damage to the sequence of nucleotides. Being analogous to uracil, 5-FU enters cells using the same transport mechanism, where a is converted into active metabolites such as fluorouridine triphosphate (FUTP), fluorodeoxyuridine monophosphate (FdUMP), and fluorodeoxyuridine triphosphate (FdUTP). Currently, there are several nanodelivery systems being developed and evaluated at the preclinical level to overcome existing limitations to 5-FU chemotherapy, including liposomes, polymeric nanoparticles, polymeric micelles, nanoemulsions, mesoporous silica nanoparticles, and solid lipid nanoparticles. Therefore, it is essential to choose and develop suitable analytical methods for the quantification of 5-FU and its metabolites (5-fluorouridine and 5-fluoro-2-deoxyuridine) in pharmaceutical and biological samples. Among the analytical techniques, chromatographic methods are commonly the most used for the quantification of 5-FU from different matrices. However, other analytical methods have also been developed for the determination of 5-FU, such as electrochemical methods, a sensitive, selective, and precise technique, in addition to having a reduced cost. Here, we first review the physicochemical properties, mechanism of action, and advances in 5-FU nanodelivery systems. Next, we summarize the current progress of other chromatographic methods described to determine 5-FU. Lastly, we discuss the advantages of electrochemical methods for the identification and quantification of 5-FU and its metabolites in pharmaceutical and biological samples.

In vivo delivery of plasmid DNA by lipid nanoparticles: the influence of ionizable cationic lipids on organ-selective gene expression

Ionizable cationic lipids play a critical role in developing new gene therapies for various biomedical applications, including COVID-19 vaccines. However, it remains unclear whether the formulation of lipid nanoparticles (LNPs) using DLin-MC3-DMA, an optimized ionizable lipid clinically used for small interfering RNA (siRNA) therapy, also facilitates high liver-selective transfection of other gene therapies such as plasmid DNA (pDNA). Here we report the first investigation into pDNA transfection efficiency in different mouse organs after intramuscular and intravenous administration of lipid nanoparticles (LNPs) where DLin-MC3-DMA, DLin-KC2-DMA or DODAP are used as the ionizable cationic lipid component of the LNP. We discovered that these three benchmark lipids previously developed for siRNA delivery followed an unexpected characteristic rank order in gene expression efficiency when utilized for pDNA. In particular, DLin-KC2-DMA facilitated higher in vivo pDNA transfection than DLin-MC3-DMA and DODAP, possibly due to its head group pK_a and lipid tail structure. Interestingly, LNPs formulated with either DLin-KC2-DMA or DLin-MC3-DMA exhibited significantly higher in vivo protein production in the spleen than in the liver. This work sheds light on the importance of the choice of ionizable cationic lipid and nucleic acid cargo for organ-selective gene expression. The study also provides a new design principle towards the formulation of more effective LNPs for biomedical applications of pDNA, such as gene editing, vaccines and immunotherapies.

Targeting the liver X receptor with dendrogenin A differentiates tumour cells to secrete immunogenic exosome-enriched vesicles

Tumour cells are characterized by having lost their differentiation state. They constitutively secrete small extracellular vesicles (sEV) called exosomes when they come from late endosomes. Dendrogenin A (DDA) is an endogenous tumour suppressor cholesterol‐derived metabolite. It is a new class of ligand of the nuclear Liver X receptors (LXR) which regulate cholesterol homeostasis and immunity. We hypothesized that DDA, which induces tumour cell differentiation, inhibition of tumour growth and immune cell infiltration into tumours, could functionally modify sEV secreted by tumour cells. Here, we have shown that DDA differentiates tumour cells by acting on the LXRβ. This results in an increased production of sEV (DDA‐sEV) which includes exosomes. The DDA‐sEV secreted from DDA‐treated cells were characterized for their content and activity in comparison to sEV secreted from control cells (C‐sEV). DDA‐sEV were enriched, relatively to C‐sEV, in several proteins and lipids such as differentiation antigens, “eat‐me” signals, lipidated LC3 and the endosomal phospholipid bis(monoacylglycero)phosphate, which stimulates dendritic cell maturation and a Th1 T lymphocyte polarization. Moreover, DDA‐sEV inhibited the growth of tumours implanted into immunocompetent mice compared to control conditions. This study reveals a pharmacological control through a nuclear receptor of exosome‐enriched tumour sEV secretion, composition and immune function. Targeting the LXR may be a novel way to reprogram tumour cells and sEV to stimulate immunity against cancer.

Development of a Dual Drug-Loaded, Surfactant-Stabilized Contrast Agent Containing Oxygen

Co-delivery of cancer therapeutics improves efficacy and encourages synergy, but delivery faces challenges, including multidrug resistance and spatiotemporal distribution of therapeutics. To address these, we added paclitaxel to previously developed acoustically labile, oxygen-core, surfactant-stabilized microbubbles encapsulating lonidamine, with the aim of developing an agent containing both a therapeutic gas and two drugs acting in combination. Upon comparison of unloaded, single-loaded, and dual-loaded microbubbles, size (~1.7 µm) and yield (~2 × 10⁹ microbubbles/mL) (~1.7) were not statistically different, nor were acoustic properties (maximum in vitro enhancements roughly 18 dB, in vitro enhancements roughly 18 dB). Both drugs encapsulated above required doses calculated for head and neck squamous cell carcinoma, the cancer of choice. Interestingly, paclitaxel encapsulation efficiency increased from 1.66% to 3.48% when lonidamine was included. During preparation, the combination of single drug-loaded micelles gave higher encapsulation (µg drug/g microbubbles) than micelles loaded with either drug alone (lonidamine, 104.85 ± 22.87 vs. 87.54 ± 16.41), paclitaxel (187.35 ± 8.38 vs. 136.51 ± 30.66). In vivo intravenous microbubbles produced prompt ultrasound enhancement within tumors lasting 3–5 min, indicating penetration into tumor vasculature. The ability to locally destroy the microbubble within the tumor vasculature was confirmed using a series of higher intensity ultrasound pulses. This ability to locally destroy microbubbles shows therapeutic promise that warrants further investigation.

In vitro and in vivo characterization of Entacapone-loaded nanostructured lipid carriers developed by quality-by-design approach

Entacapone, a reversible catechol-o-methyl transferase inhibitor, is used to enhance the action of dopamine agonists by reducing their metabolism and the 'Wearing-off' effects associated with long-term use in the treatment of Parkinson's disease. It is used as an adjunct to levodopa/Carbidopa therapy. Due to limited dissolution and first-pass clearance, it suffers low and variable bioavailability issues. To overcome this problem, the present study aims to explore the potential of nanostructured lipid carriers (NLCs) for the delivery of Entacapone. The Quality by Design (QbD) approach was used for the systematic development of NLCs. The 2³ full factorial designs were investigated using Design-Expert®11 software. The three independent variables namely content of total lipid (X1), surfactant (X2), and sonication time (X3) were optimized against two responses namely particle size and entrapment efficiency. The optimized NLCs were characterized for their size, surface morphology, entrapment efficiency, drug release, thermal and crystallographic studies. In-vivo pharmacokinetic studies in Entacapone-loaded NLCs showed an increase in t_1/2, AUC_0-∞, MRT compared to free drug. The reduction in elimination (Kel) depicts the prolonged action of Entacapone by loading in NLCs. The results displayed Entacapone-loaded NLCs have promising potential for oral delivery and enhanced therapeutic effect which otherwise was a major issue.

Protective effect of l-carnitine-loaded solid lipid nanoparticles against H2O2-induced genotoxicity and apoptosis

L-carnitine (LC) is a highly water-soluble compound involved in the β-oxidation of lipids and transportation of long-chain fatty acids across the membrane of mitochondria. However, the higher hydrophilicity of LC limits its free diffusion across the bilayer lipid membrane of intestinal epithelium in oral administration, decreasing oral bioavailability. Drug delivery with nanoparticles enhances cargo bioavailability and cellular uptake and improves therapeutic outcomes while decreasing unwanted side effects. Here, we proposed solid lipid nanoparticles (SLNs) as a hydrophobic carrier for LC delivery, aiming at increasing LC bioavailability and its protective role against intracellular oxidative stress damages. The LC-SLNs were prepared using the hot homogenization technique, and different physicochemical properties were investigated. The inhibition of H₂O₂-induced ROS generation in human umbilical vein endothelial cells (HUVECs) with plain LC and LC-SLNs was investigated. Moreover, various in vitro experiments were performed to assess whether LC-SLNs can protect HUVECs from H₂O₂-induced genotoxicity and apoptosis. The monodispersed and spherical blank SLNs and LC-SLNs were 104 ± 1.8 and 128 ± 1.5 nm, respectively with a drug loading (DL) of 11.49 ± 0.78 mg/mL and acceptable encapsulation efficiency (EE%) (69.09 ± 1.12) of LC-SLNs. The formulation process did not affect the antioxidant properties of LC. MTT assay and comet assay demonstrated that the LC-SLNs decreased cytotoxicity and genotoxicity of H₂O₂, respectively on HUVECs. Besides, LC-SLNs more inhibited ROS generation, along with apoptotic events in H₂O₂-treated HUVECs compared to the plain LC. Altogether, our findings affirmed the protective effects of LC-SLNs against H₂O₂-induced genotoxicity and apoptosis in HUVECs. In conclusion, LC-SLN formulation is a promising drug delivery system to overcome the bioavailability issue of hydrophilic LC, enhancing the antioxidant and biological properties of the plain LC.

The Phenomenon of Drug Emulsion Carriers Compaction during Their Movement in Microstructures

The greatest challenges of modern pharmacology are the design of drugs with the highest possible efficacy of an active substance and with the lowest possible invasiveness for the whole organism. A good solution features the application of a bioactive substance in different carriers. The effectiveness of such preparations is determined not only by the properties of the drug, but primarily by the dynamics of carrier movement in the body. This is the reason why studies on the dispersed systems transport in micro- and nanostructures are becoming important. This paper presents a study of emulsion systems transport in microcapillaries. A dispersed phase thickening effect was observed during the process, which resulted in a concentration increase of the flowing emulsion, in some cases up to 10 times. This phenomenon directly influences transport dynamics of such substances in microstructures and should be taken into account when designing drug parameters (concentration, release time, and action range). The effect was investigated for three different emulsions concentrations and presented quantitatively. The scales of this phenomenon occurrence at different flow conditions were investigated, and their magnitudes were modelled and described. This allows the prediction of the flow resistance in the movement of given dispersion systems, as a function of the flow rate, the emulsion parameters, and the microchannel size.

Preformulation and characterization of raloxifene-loaded lipid nanoparticles for transdermal administration

Transdermal administration of raloxifene hydrochloride (RLX)-loaded nanostructured lipid carriers (NLCs) has been proposed to circumvent its low oral bioavailability (2%). Preformulation studies were carried out to evaluate drug-excipient compatibility of various adjuvants commonly used for NLC preparation (waxes, cholesterol, compritol, gelucire, span 60, span 80, span 85, tween 80, poloxamer 188, oleic acid, caprylic/capric triglyceride, and castor oil). It was used differential scanning calorimetry (DSC), isothermal stress testing (IST), and solubility studies. The most promising excipients were chosen for NLC obtention, and full characterization was done, including in vitro skin permeation. DSC curves suggested drug-excipient interaction among some compounds, and the IST study showed incompatibility of RLX with waxes, compritol, cholesterol, span 60, and poloxamer 188. Solubility studies helped select gelucire, caprylic/capric triglyceride, span 80, and tween 80 for NLC production. Twelve NLCs were obtained (NLC1 to NLC12), but NLC7 and NLC8 were the most promising ones. In vitro release studies demonstrated that NLC7 and NLC8 were able to control RLX release (14.74 and 9.07% at 24 h, respectively) compared with the unloaded drug (> 90% at 24 h). Unloaded RLX did not permeate the diffusion cells' receptor medium and showed higher drug skin retention (11-fold) than RLX-loaded NLC. NLC reduced RLX skin retention, favoring drug permeation to deeper skin layers. NLC7 increased drug flux is 2.4-fold. NLC7 is a promising formulation for RLX transdermal drug delivery.