Effect of Micromixer Design on Lipid Nanocarriers Manufacturing for the Delivery of Proteins and Nucleic Acids

Lipid-based nanocarriers have emerged as helpful tools to deliver sensible biomolecules such as proteins and oligonucleotides. To have a fast and robust microfluidic-based nanoparticle synthesis method, the setup of versatile equipment should allow for the rapid transfer to scale cost-effectively while ensuring tunable, precise and reproducible nanoparticle attributes. The present work aims to assess the effect of different micromixer geometries on the manufacturing of lipid nanocarriers taking into account the influence on the mixing efficiency by changing the fluid-fluid interface and indeed the mass transfer. Since the geometry of the adopted micromixer varies from those already published, a Design of Experiment (DoE) was necessary to identify the operating (total flow, flow rate ratio) and formulation (lipid concentration, lipid molar ratios) parameters affecting the nanocarrier quality. The suitable application of the platform was investigated by producing neutral, stealth and cationic liposomes, using DaunoXome®, Myocet®, Onivyde® and Onpattro® as the benchmark. The effect of condensing lipid (DOTAP, 3-10-20 mol%), coating lipids (DSPE-PEG550 and DSPE-PEG2000), as well as structural lipids (DSPC, eggPC) was pointed out. A very satisfactory encapsulation efficiency, always higher than 70%, was successfully obtained for model biomolecules (myoglobin, short and long nucleic acids).

Effective γδ T-cell clinical therapies: current limitations and future perspectives for cancer immunotherapy

γδ T cells are a unique subset of T lymphocytes, exhibiting features of both innate and adaptive immune cells and are involved with cancer immunosurveillance. They present an attractive alternative to conventional T cell-based immunotherapy due, in large part, to their lack of major histocompatibility (MHC) restriction and ability to secrete high levels of cytokines with well-known anti-tumour functions. To date, clinical trials using γδ T cell-based immunotherapy for a range of haematological and solid cancers have yielded limited success compared with in vitro studies. This inability to translate the efficacy of γδ T-cell therapies from preclinical to clinical trials is attributed to a combination of several factors, e.g. γδ T-cell agonists that are commonly used to stimulate populations of these cells have limited cellular uptake yet rely on intracellular mechanisms; administered γδ T cells display low levels of tumour-infiltration; and there is a gap in the understanding of γδ T-cell inhibitory receptors. This review explores the discrepancy between γδ T-cell clinical and preclinical performance and offers viable avenues to overcome these obstacles. Using more direct γδ T-cell agonists, encapsulating these agonists into lipid nanocarriers to improve their pharmacokinetic and pharmacodynamic profiles and the use of combination therapies to overcome checkpoint inhibition and T-cell exhaustion are ways to bridge the gap between preclinical and clinical success. Given the ability to overcome these limitations, the development of a more targeted γδ T-cell agonist-checkpoint blockade combination therapy has the potential for success in clinical trials which has to date remained elusive.

Nanostructured Lipid Carriers as Robust Systems for Lupeol Delivery in the Treatment of Experimental Visceral Leishmaniasis

Leishmaniasis is a neglected tropical disease that affects millions of people around the world. Available therapy causes severe side effects, has unacceptable prices for some specific formulations, and the existence of drug-resistant parasites limits the use of the currently available arsenal of antiparasitic drugs. Therefore, natural products serve as one of the main sources to develop new and effective alternative drugs against leishmaniasis. In this sense, the present study evaluated the potential of the triterpene Lupeol (Lu) entrapped in nanostructured lipid carriers (NLCs) for the treatment of experimental visceral leishmaniasis. The therapeutic efficacy of Lu or Lu entrapped in NLC (Lu-NLC) was investigated in golden hamsters infected with Leishmania (Leishmania) infantum. Lu-NLC presented a mean particle size of 265.3 ± 4.6 nm, a polydispersity index of <0.25 and a zeta potential of -37.2 ± 0.84 mV; the efficacy of encapsulation was 84.04 ± 0.57%. Studies on hamsters showed that Lu-NLC (5 mg/kg) administered intraperitoneally for 10 consecutive days caused a reduction of 99.9% in the number of parasites in the spleen and liver compared to the untreated infected control. On the contrary, Lu-treated animals (5 mg/kg) had 94.4 and 90.2% less parasites in the spleen and liver, respectively, than the infected group. Additionally, a significant preservation of splenic and hepatic tissues was observed in animals treated with Lu-NLC or Lu. Furthermore, Lu-NLC-treated animals produced high levels of anti-Leishmania IgG2 isotype. These data indicate that NLC potentialized Lu efficacy in experimental visceral leishmaniasis. This work suggests that Lu and nanoformulations carrying this compound may be considered as an important tool to be included in the alternative therapy of leishmaniasis.

Lipid-, Inorganic-, Polymer-, and DNA-Based Nanocarriers for Delivery of the CRISPR/Cas9 system

The clustered regularly interspaced short palindromic repeat (CRISPR)/associated protein 9 (CRISPR/Cas9) system has been widely explored for the precise manipulation of target DNA and has enabled efficient genomic editing in cells. Recently, CRISPR/Cas9 has shown promising potential in biomedical applications, including disease treatment, transcriptional regulation and genome-wide screening. Despite these exciting achievements, efficient and controlled delivery of the CRISPR/Cas9 system has remained a critical obstacle to its further application. Herein, we elaborate on the three delivery forms of the CRISPR/Cas9 system, and discuss the composition, advantages and limitations of these forms. Then we provide a comprehensive overview of the carriers of the system, and focus on the nonviral nanocarriers in chemical methods that facilitate efficient and controlled delivery of the CRISPR/Cas9 system. Finally, we discuss the challenges and prospects of the delivery methods of the CRISPR/Cas9 system in depth, and propose strategies to address the intracellular and extracellular barriers to delivery in clinical applications.

Lipid-Based Nanocarriers in the Treatment of Glioblastoma Multiforme (GBM): Challenges and Opportunities

Glioblastoma multiforme (also known as glioblastoma; GBM) is one of the most malignant types of brain tumors that occurs in the CNS. Treatment strategies for glioblastoma are majorly comprised of surgical resection, radiotherapy, and chemotherapy along with combination therapy. Treatment of GBM is itself a tedious task but the involved barriers in GBM are one of the main impediments to move one step closer to the treatment of GBM. Basically, two of the barriers are of utmost importance in this regard, namely blood brain barrier (BBB) and blood brain tumor barrier (BBTB). This review will address different challenges and barriers in the treatment of GBM along with their etiology. The role and recent progress of lipid-based nanocarriers like liposomes, solid lipid nanocarriers (SLNs), nanostructured lipid carriers (NLCs), lipoplexes, and lipid hybrid carriers in the effective management of GBM will be discussed in detail.

Potential of Nano-Antioxidants and Nanomedicine for Recovery from Neurological Disorders Linked to Long COVID Syndrome

Long-term neurological complications, persisting in patients who cannot fully recover several months after severe SARS-CoV-2 coronavirus infection, are referred to as neurological sequelae of the long COVID syndrome. Among the numerous clinical post-acute COVID-19 symptoms, neurological and psychiatric manifestations comprise prolonged fatigue, "brain fog", memory deficits, headache, ageusia, anosmia, myalgias, cognitive impairments, anxiety, and depression lasting several months. Considering that neurons are highly vulnerable to inflammatory and oxidative stress damages following the overproduction of reactive oxygen species (ROS), neuroinflammation and oxidative stress have been suggested to dominate the pathophysiological mechanisms of the long COVID syndrome. It is emphasized that mitochondrial dysfunction and oxidative stress damages are crucial for the pathogenesis of neurodegenerative disorders. Importantly, antioxidant therapies have the potential to slow down and prevent disease progression. However, many antioxidant compounds display low bioavailability, instability, and transport to targeted tissues, limiting their clinical applications. Various nanocarrier types, e.g., liposomes, cubosomes, solid lipid nanoparticles, micelles, dendrimers, carbon-based nanostructures, nanoceria, and other inorganic nanoparticles, can be employed to enhance antioxidant bioavailability. Here, we highlight the potential of phytochemical antioxidants and other neuroprotective agents (curcumin, quercetin, vitamins C, E and D, melatonin, rosmarinic acid, N-acetylcysteine, and Ginkgo Biloba derivatives) in therapeutic strategies for neuroregeneration. A particular focus is given to the beneficial role of nanoparticle-mediated drug-delivery systems in addressing the challenges of antioxidants for managing and preventing neurological disorders as factors of long COVID sequelae.

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.

Formulation and Evaluation of Topical Biodegradable Films Loaded with Levofloxacin Lipid Nanocarriers

Skin ulcers have increased sharply due to rise in the incidence of obesity and diabetes. This study investigated lipid nanocarriers as a strategy to improve the efficacy of levofloxacin (LV) in penetrating skin. Two surfactant types and different lipid mixtures were used in preparation of lipid nanocarriers. Mean particle size, percentage entrapment efficiency (%EE), in vitro release, and antimicrobial activity were examined. The selected formula was incorporated into a chitosan (CS) film that was subjected to physic-chemical characterization and ex vivo permeation study. The selected formula showed particle size, PDI, and ZP: 80.3 nm, -0.21, and -26 mV, respectively, synchronized with 82.12 %EE. In vitro release study showed slow biphasic release of LV from lipid nanocarriers. The antimicrobial effect illustrated statistically significant effect of lipid nanocarriers on decreasing the minimum effective concentration (MIC) of LV, particularly against E. coli. The optimized nanocarriers' formula loaded into CS film was clear, colorless, translucent, and smooth in texture. Based on the release profiles, it could be speculated that the CS film loaded with LV nanocarriers can maintain the antibacterial activity for 4 consecutive days. Thus, the local delivery of the drug in a sustained release manner could be predicted to enhance the therapeutic effect. Further clinical studies are strongly recommended. Graphical Abstract.

Nanotechnologies for intranasal drug delivery: an update of literature

Scientific research has focused its attention on finding an alternative route to systemic oral and parenteral administration, to overcome their usual drawbacks, such as hepatic first-pass which decreases drug bioavailability after oral administration, off-target effects, low patient compliance and low speed of onset of the pharmacological action in first-aid cases. Innovative drug delivery systems (DDS), mainly based on polymer and lipid biocompatible materials, have given a great prompt in this direction in the last years. The intranasal (IN) route of administration is a valid non-invasive alternative. It is highly suitable for self-administration, the drug quickly reaches the bloodstream, largely avoiding the first pass effect, and can also reach directly the brain bypassing BBB. Association of IN route with DDS can thus become a winning strategy for the controlled delivery of drugs, especially when a very quick effect is desired or needed. This review aims at analyzing the scientific literature regarding IN-DDS and their different ways of administration (systemic, topical, pulmonary, nose-to-brain). In particular, attention was devoted to polymer- and lipid-based micro- and nanocarriers, being the topic of most published articles in the last decade, but the whole plethora of colloidal DDS investigated in recent years for IN administration was presented.

Recent Advancement in Topical Nanocarriers for the Treatment of Psoriasis

Psoriasis is a life-threatening autoimmune inflammatory skin disease, triggered by T lymphocyte. Recently, the drugs most commonly used for the treatment of psoriasis include methotrexate (MTX), cyclosporine (CsA), acitretin, dexamethasone, and salicylic acid. However, conventional formulations due to poor absorptive capacity, inconsistent drug release characteristics, poor capability of selective targeting, poor retention of drug molecules in target tissue, and unintended skin reactions restrict the clinical efficacy of drugs. Advances in topical nanocarriers allow the development of prominent drug delivery platforms can be employed to address the critical issues associated with conventional formulations. Advances in nanocarriers design, nano-dimensional configuration, and surface functionalization allow formulation scientists to develop formulations for a more effective treatment of psoriasis. Moreover, interventions in the size distribution, shape, agglomeration/aggregation potential, and surface chemistry are the significant aspects need to be critically evaluated for better therapeutic results. This review attempted to explore the opportunities and challenges of current revelations in the nano carrier-based topical drug delivery approach used for the treatment of psoriasis.

Formulative Study and Intracellular Fate Evaluation of Ethosomes and Transethosomes for Vitamin D3 Delivery

In this pilot study, ethosomes and transethosomes were investigated as potential delivery systems for cholecalciferol (vitamin D3), whose deficiency has been correlated to many disorders such as dermatological diseases, systemic infections, cancer and sarcopenia. A formulative study on the influence of pharmaceutically acceptable ionic and non-ionic surfactants allowed the preparation of different transethosomes. In vitro cytotoxicity was evaluated in different cell types representative of epithelial, connective and muscle tissue. Then, the selected nanocarriers were further investigated at light and transmission electron microscopy to evaluate their uptake and intracellular fate. Both ethosomes and transethosomes proven to have physicochemical properties optimal for transdermal penetration and efficient vitamin D3 loading; moreover, nanocarriers were easily internalized by all cell types, although they followed distinct intracellular fates: ethosomes persisted for long times inside the cytoplasm, without inducing subcellular alteration, while transethosomes underwent rapid degradation giving rise to an intracellular accumulation of lipids. These basic results provide a solid scientific background to in vivo investigations aimed at exploring the efficacy of vitamin D3 transdermal administration in different experimental and pathological conditions.

Tuberculosis Treatment Facilitated by Lipid Nanocarriers: Can Inhalation Improve the Regimen?

Tuberculosis (TB) remains a major global health problem. Conventional treatments fail either because of poor patient compliance with the drug regimen or due to the emergence of multidrug-resistant TB. Thus, not only has the discovery of new compounds and new therapeutic strategies been the focus of many types of research but also new routes of administration. Pulmonary drug delivery possesses many advantages, including the noninvasive route of administration, low metabolic activity, and control environment for systemic absorption, and avoids first-pass metabolism. The use of lipid nanocarriers provides several advantages such as protection of the compound's degradation, increased bioavailability, and controlled drug release. In this study, we review some points related to how the use of lipid nanocarriers can improve TB treatment with inhaled nanomedicines. This review also discusses the current approaches and formulations developed to achieve optimal pulmonary drug delivery systems with nanocarriers targeting alveolar macrophages.

Emerging Trends in Topical Delivery of Curcumin Through Lipid Nanocarriers: Effectiveness in Skin Disorders

Curcumin is a unique molecule naturally obtained from rhizomes of Curcuma longa. Curcumin has been reported to act on diverse molecular targets like receptors, enzymes, and co-factors; regulate different cellular signaling pathways; and modulate gene expression. It suppresses expression of main inflammatory mediators like interleukins, tumor necrosis factor, and nuclear factor κB which are involved in the regulation of genes causing inflammation in most skin disorders. The topical delivery of curcumin seems to be more advantageous in providing a localized effect in skin diseases. However, its low aqueous solubility, poor skin permeation, and degradation hinder its application for commercial use despite its enormous potential. Lipid-based nanocarrier systems including liposomes, niosomes, solid lipid nanoparticles, nanostructured lipid carriers, lyotropic liquid crystal nanoparticles, lipospheres, and lipid nanocapsules have found potential as carriers to overcome the issues associated with conventional topical dosage forms. Nano-size, lipophilic nature, viscoelastic properties, and occlusive effect of lipid nanocarriers provide high drug loading, hydration of skin, stability, enhanced permeation through the stratum corneum, and slow release of curcumin in the targeted skin layers. This review particularly focuses on the application of lipid nanocarriers for the topical delivery of curcumin in the treatment of various skin diseases. Furthermore, preclinical studies and patents have also indicated the emerging commercialization potential of curcumin-loaded lipid nanocarriers for effective drug delivery in skin disorders. Graphical Abstract.

In vivo toxicity evaluation of nanoemulsions for drug delivery

Lipid nanocarriers (LNs), for example nanoemulsions (NE), are an emerging tool for drug delivery due to their ability to incorporate drugs, protect the drug from degradation, improve bioavailability, and control release. Although LNs are widely studied and applied, especially in the pharmaceutical field, knowledge about their toxicity is scarce. Moreover, the majority of studies focus on their efficiency rather than safety. Thus, the aim of this study was to evaluate the possible toxic effects of NE in vivo. Male Wistar rats (2 months old, 250 g) were treated once daily for 21 days with NE via oral or intraperitoneal delivery at 200, 400 or 800 mg lipid/kg body weight. At the end of the experiment, biochemical, hematological, oxidative stress, and genotoxicity parameters were analyzed. Our results showed that treatment with NE did not modify organ weight or biochemical parameters when compared to controls. The highest NE dose (800 mg/kg) via intraperitoneal injection caused changes in hematological parameters, namely increased plasma proteins, platelets, total leukocytes, and neutrophils, findings that suggest an inflammatory reaction. Further, the same dose evoked lipid peroxidation in the liver. Taken together, the results from this study suggest that NEs can be considered safe for oral administration, but high doses via the parenteral route can cause toxic effects. This study contributes to knowledge about NE toxicity and provides important data about their safe use in the pharmaceutical field.

Overview on Inhalable Nanocarriers for Respiratory Immunization

Despite the value of vaccination, the control of re-emerging infectious and non-infectious diseases remains a challenge for researchers. In this topic, mucosal immunization, in particular at airway mucosa, is receiving increased investigational focus. Innovative vaccine platforms to deliver immunogens with or without adjuvants in a safe and stable manner have been explored to improve vaccine efficacy and induce long-term and protective immunity. This review provides an overview of the features of respiratory immunization and the fate of inhalable nanocarriers in the respiratory tract. The review also highlights the most representative delivery approaches based on inhalable nanocarriers, including polymeric, lipid and inorganic-based nanosystems, which can enhance vaccine uptake by antigen-presenting cells. The review takes into consideration the most relevant and recent in vivo studies to provide readers a realistic insight into the potential of these technologies in the advantages and potential hurdles to clinical and commercial success of these platforms for vaccination.

Development, Optimization, and In Vitro/In Vivo Characterization of Enhanced Lipid Nanoparticles for Ocular Delivery of Ofloxacin: the Influence of Pegylation and Chitosan Coating

This study aims to investigate whether modification of solid lipid nanoparticles (SLNs) with chitosan (CTS) and polyethylene glycol (PEG) coatings enhances corneal retention time and transcorneal bioavailability. Ofloxacin (OFLOX) was selected as the model drug because of its potential benefits for the treatment of local eye infections. The OFLOX-CTS-PEG-SLN was prepared by a modified emulsion/solvent evaporation technique. A central composite design was implemented to investigate the influence of total lipid/drug ratio, surfactant concentration, PEG stearate concentration in the lipid mixture, and CTS concentration on size, entrapment, transcorneal permeation, and adhesion to the corneal mucosal membrane. The optimized OFLOX-CTS-PEG-SLN was characterized for OFLOX cumulative percentage released in simulated tear fluid and permeated across the excised bovine corneal membrane. Moreover, nanoparticle morphology, eye irritation via histopathological analysis, and OFLOX concentration in the ocular fluids and tissues were determined. A total lipid/drug ratio of 19:1, Tween 80 of 2%, PEG stearate concentration in the lipid mixture (% w/w) of 2.6%, and CTS concentration (% w/v) of 0.23% produced 132.9 nm particles entrapping 74.8% of the total drug added. The particles detached from the corneal membrane at a force of 3700 dyne/cm². The %OFLOX released from the optimized nanoparticles was 63.3, and 66% of the drug permeated after 24 h. Compared to Oflox® drops, the optimized OFLOX-CTS-PEG-SLN exhibited similar tolerability but two- to threefold higher concentrations in the eyes of rabbits. Coating of SLN with chitosan and PEG augments the ocular bioavailability of OFLOX by increasing transcorneal permeation and enhancing mucoadhesion strength.

Anti-EGF Receptor Aptamer-Guided Co-Delivery of Anti-Cancer siRNAs and Quantum Dots for Theranostics of Triple-Negative Breast Cancer

Many aptamers have been evaluated for their ability as drug delivery vehicles to target ligands, and a variety of small interfering RNAs (siRNAs) have been tested for their anti-cancer properties. However, since these two types of molecules have similar physicochemical properties, it has so far been difficult to formulate siRNA-encapsulating carriers guided by aptamers. Here, we propose aptamer-coupled lipid nanocarriers encapsulating quantum dots (QDs) and siRNAs for theragnosis of triple-negative breast cancer (TNBC).

Methods: Hydrophobic QDs were effectively incorporated into lipid bilayers, and then therapeutic siRNAs were complexed with QD-lipid nanocarriers (QLs). Finally, anti-EGFR aptamer-lipid conjugates were inserted into the QLs for TNBC targeting (aptamo-QLs). TNBC-targeting aptamo-QLs were directly compared to anti-EGFR antibody-coupled immuno-QLs. The in vitro delivery of therapeutic siRNAs and QDs to target cells was assessed by flow cytometry and confocal microscopy. The in vivo targeting of siRNAs to tumors and their therapeutic efficacy were evaluated in mice carrying MDA-MB-231 tumors.

Results: Both types of EGFR-targeting QLs showed enhanced delivery to target cancer cells, resulting in more effective gene silencing and enhanced tumor imaging compared to non-targeting control QLs. Moreover, combinatorial therapy with Bcl-2 and PKC-ι siRNAs loaded into the anti-EGFR QLs was remarkably effective in inhibiting tumor growth and metastasis.

Conclusion: In general, the aptamo-QLs showed competitive in vivo delivery and therapeutic efficacy compared to immuno-QLs under the same experimental conditions. Our results show that the anti-EGFR aptamer-guided lipid carriers may be a potential theranostic delivery vehicle for RNA interference and fluorescence imaging of TNBCs.

Preclinical Explorative Assessment of Celecoxib-Based Biocompatible Lipidic Nanocarriers for the Management of CFA-Induced Rheumatoid Arthritis in Wistar Rats

Celecoxib (CXB), a COX-2 inhibitor, is primarily indicated for long-term treatment of rheumatoid arthritis (RA). The effective therapeutic efficacy of CXB on RA via oral administration shows adverse systemic complications, and therefore, local application of CXB has been recommended. The aim of the present study was to develop and characterize solid lipid nanoparticles (SLNs) with enhanced skin permeation potential of CXB. The particle size, polydispersity index (PDI), and percentage drug entrapment (PDE) of the developed SLNs (CXB-SLNs) were found to be 240 nm, < 0.3, and ~ 86% respectively. The developed SLNs exhibited sustained release up to 70% at the end of 48 h. Drug permeation was found to be 45% for SLN gel and 31% for conventional gel. The dermatokinetic studies also confirmed enhanced permeation of CXB in the epidermis and dermis and revealed superiority of the developed SLN gel vis-à-vis the conventional gel. Further, in the CFA-induced arthritis rat model, % arthritis index (AI) of the CXB-SLN gel formulation was found to be very less (18.54%) as compared to untreated (187.34%) and conventional gel-treated (91.61%) animals. In conclusion, the current study can provide a suitable alternative for the development of an effective topical formulation of CXB in lipid nanocarriers.

Resveratrol-Loaded Lipid Nanocarriers: Correlation between In Vitro Occlusion Factor and In Vivo Skin Hydrating Effect

Lipid nanocarriers show occlusive properties that may be related to their ability to improve skin hydration. The aim of this work was to evaluate the relationship between in vitro occlusion factor and in vivo skin hydration for three types of lipid nanocarriers: nanoemulsions (NEs), solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). These lipid nanocarriers were loaded with trans-resveratrol (RSV) and incorporated in gel vehicles. In vitro occlusion factor was in the order SLNs > NLCs > NEs. Gels containing unloaded or RSV loaded lipid nanocarriers were applied on the back of a hand of 12 healthy volunteers twice a day for one week, recording skin hydration changes using the instrument Soft Plus. An increase of skin hydration was observed for all lipid nanocarriers (SLNs > NLCs > NEs). RSV loading into these nanocarriers did not affect in vitro and in vivo lipid nanocarriers effects. A linear relationship (r² = 0.969) was observed between occlusion factor and in vivo increase of skin hydration. Therefore, the results of this study showed the feasibility of using the occlusion factor to predict in vivo skin hydration resulting from topical application of different lipid nanocarriers loading an active ingredient with no inherent hydrating activity.

Targeting and microenvironment-responsive lipid nanocarrier for the enhancement of tumor cell recognition and therapeutic efficiency

Poor recognition and penetration of chemotherapeutic agents in solid tumors have been recognized as one of the major challenges limiting the efficacy of cancer therapies. Folic acid and tumor microenvironment-sensitive polypeptide (TMSP) co-modified lipid-nanocarrier (F/TMSP-NLC) are successfully formulated in response to the overexpression of folate receptor (FR) and the upregulation of matrix metalloproteinase-2 (MMP-2) in tumor microenvironment. The F/TMSP-NLC accumulates in tumor via the enhanced permeability and retention (EPR) effect, and folate moiety binds selectively to the FR once it reaches the tumor. In addition, cell-penetrating peptide (CPP)-penetrating activity is initiated by MMP-2 protease-oversecretion tumor. The specificity and efficacy of the co-modified nanocarriers to tumor are investigated in KB, HT-1080 and A549 cells in vitro. Multivalent interactions induce the enhancement of cancer cell recognition and internalization, which subsequently result in cancer cell apoptosis or death. The F/TMSP-NLC shows long-circulation effect, high accumulation in tumor, strong tumor inhibition, increased apoptotic indices, and negligible toxicity in vivo. In conclusion, the present nanocarrier modified with both TMSP and folic acid is a potential drug delivery system for tumor cell recognition and therapy, implying that using more than one target from the pool of tumor-stroma interactions is profoundly beneficial to therapeutic approaches.

Lipid nanocarriers of a lipid-conjugated estrogenic derivative inhibit tumor growth and enhance cisplatin activity against triple-negative breast cancer: pharmacokinetic and efficacy evaluation

Breast cancer is the leading cause of malignancies among women globally. The triple negative breast cancer (TNBC) subtype is the most difficult to treat and accounts for 15% of all cases. Targeted therapies have been developed for TNBC but come short of clinical translation due to acquired tumor resistance. An effective therapy against TNBC must combine properties of target specificity, efficient tumor killing, and translational relevance. The objective of this study was to formulate a nontoxic, cationic, lipid-conjugated estrogenic derivative (ESC8), with demonstrated anticancer activity, for oral delivery in mice bearing triple negative breast cancer (TNBC) as xenograft tumors. The in vitro cell viability, Caco-2 permeability, and cell cycle dynamics of ESC8-treated TNBC cells were investigated. ESC8 was formulated as liposomes, solid lipid nanoparticles (SLNs), and nanostructured lipid carriers (NLCs) and characterized for size, zeta potential, entrapment efficiency, size stability, and tumor biodistribution. Pharmacokinetic modeling of plasma concentration-time course data was carried out following intravenous and oral administration in Sprague-Dawley rats. In vivo efficacy investigation of ESC8-SLNC was carried out in Nu/Nu mice bearing MDA-MB-231 TNBC as xenograft tumors, and the molecular dynamics modulating tumor growth inhibition was analyzed by Western blot. In vitro ESC8 inhibited TNBC and non-TNBC cell viability with IC50 ranging from 1.81 to 3.33 μM. ESC8 was superior to tamoxifen and Cisplatin in inhibiting MDA-MB-231 cell viability; and at 2.0 μM ESC8 enhanced Cisplatin cytotoxicity 16-fold. Intravenous ESC8 (2.0 mg/kg) was eliminated at a rate of 0.048 ± 0.01 h(-1) with a half-life of 14.63 ± 2.95 h in rats. ESC8 was orally bioavailable (47.03%) as solid lipid nanoparticles (ESC8-SLN). ESC8-SLN (10 mg/kg/day, ×14 days, p.o.) inhibited breast tumor growth by 74% (P < 0.0001 vs control) in mice bearing MDA-MB-231 cells as xenografts; and when given in combination with Cisplatin (2.0 mg/kg/biweekly, ×2 weeks, IV), tumor growth was inhibited by 87% (P = 0.0002, vs ESC8-SLN; 10 mg/kg/day, ×14 days, p.o). ESC8-SLN tumor growth inhibition was associated with increased expression of p21 and Caspase-9; as well as by inhibition of EGFR, Slug, p-Akt1, Vimentin, NFkβ, and IKKγ. These results show the promise of ESC8 as an oral adjuvant or neoadjuvant against triple negative breast cancer.

From molecular to nanotechnology strategies for delivery of neurotrophins: emphasis on brain-derived neurotrophic factor (BDNF)

Neurodegenerative diseases represent a major public health problem, but beneficial clinical treatment with neurotrophic factors has not been established yet. The therapeutic use of neurotrophins has been restrained by their instability and rapid degradation in biological medium. A variety of strategies has been proposed for the administration of these leading therapeutic candidates, which are essential for the development, survival and function of human neurons. In this review, we describe the existing approaches for delivery of brain-derived neurotrophic factor (BDNF), which is the most abundant neurotrophin in the mammalian central nervous system (CNS). Biomimetic peptides of BDNF have emerged as a promising therapy against neurodegenerative disorders. Polymer-based carriers have provided sustained neurotrophin delivery, whereas lipid-based particles have contributed also to potentiation of the BDNF action. Nanotechnology offers new possibilities for the design of vehicles for neuroprotection and neuroregeneration. Recent developments in nanoscale carriers for encapsulation and transport of BDNF are highlighted.