Nanostructured lipid carriers for site-specific drug delivery

Enhancing the solubility of nitazoxanide with solid dispersions technique: formulation, evaluation, and cytotoxicity study

Nitazoxanide (NTZ) is a synthetic form of nitrothiazole with a broad range of applications as an antiparasitic, antibacterial and antiviral agent. NTZ is a highly low aqueous soluble drug which possesses solubility of 0.00755 mg/mL and typically low bioavailability of 1%. Low aqueous solubility is usually regarded as prime prerequisites for enhanced absorption and bioavailability. The purpose of this study is to improve in vitro dissolution of the poorly soluble drug NTZ through amorphous solid dispersion technology. Three solid dispersions of NTZ were successfully prepared by hot-melt technique. It was further evaluated for drug content, DSC, XRD, SEM, TEM, FT-IR, in-vitro drug release study, in vitro MTT safety on HEK-293 and A-549 and stability study. The results of XRD showed after the formation of solid dispersions. The number of crystalline peaks has disappeared and confirmed the amorphous form of the drug. An in vitro release study showed that NTZ effectively released from solid dispersion into a simulated gastric releasing medium (pH 1.2). Further, the cytotoxicity study gave an indication of safe for human. Also, stability studies depicted no evident difference in the physical state of solid dispersion after six months. Hence, it can be concluded that the newly developed formulation was found to be safe and stable with enhanced solubility profile.

EGFR targeting for cancer therapy: Pharmacology and immunoconjugates with drugs and nanoparticles

The epidermal growth factor receptor (EGFR) belongs to the tyrosine kinase receptors family and is present in the epithelial cell membrane. Its endogenous activation occurs through the binding of different endogenous ligands, including the epidermal growth factor (EGF), leading to signaling cascades able to maintain normal cellular functions. Although involved in the development and maintenance of tissues in normal conditions, when EGFR is overexpressed, it stimulates the growth and progression of tumors, resulting in angiogenesis, invasion and metastasis, through some main cascades such as Ras/Raf/MAPK, PIK-3/AKT, PLC-PKC and STAT. Besides, considering the limitations of conventional chemotherapy that result in high toxicity and low tumor specificity, EGFR is currently considered an important target. As a result, several monoclonal antibodies are currently approved for use in cancer treatment, such as cetuximab (CTX), panitumumab, nimotuzumab, necitumumab and others are in clinical trials. Aiming to combine the chemotherapeutic agent toxicity and specific targeting to EGFR overexpressing tumor tissues, two main strategies will be discussed in this review: antibody-drug conjugates (ADCs) and antibody-nanoparticle conjugates (ANCs). Briefly, ADCs consist of antibodies covalently linked through a spacer to the cytotoxic drug. Upon administration, binding to EGFR and endocytosis, ADCs suffer chemical and enzymatic reactions leading to the release and accumulation of the drug. Instead, ANCs consist of nanotechnology-based formulations, such as lipid, polymeric and inorganic nanoparticles able to protect the drug against inactivation, allowing controlled release and also passive accumulation in tumor tissues by the enhanced permeability and retention effect (EPR). Furthermore, ANCs undergo active targeting through EGFR receptor-mediated endocytosis, leading to the formation of lysosomes and drug release into the cytosol. Herein, we will present and discuss some important aspects regarding EGFR structure, its role on internal signaling pathways and downregulation aspects. Then, considering that EGFR is a potential therapeutic target for cancer therapy, the monoclonal antibodies able to target this receptor will be presented and discussed. Finally, ADCs and ANCs state of the art will be reviewed and recent studies and clinical progresses will be highlighted. To the best of our knowledge, this is the first review paper to address specifically the EGFR target and its application on ADCs and ANCs.

Evaluation of in vitro and in vivo Efficacy of a Novel Amphotericin B-Loaded Nanostructured Lipid Carrier in the Treatment of Leishmania braziliensis Infection

Background

Leishmaniasis is a neglected disease, and the current therapeutic arsenal for its treatment is seriously limited by high cost and toxicity. Nanostructured lipid carriers (NLCs) represent a promising approach due to high drug loading capacity, controlled drug release profiles and superior stability. Here, we explore the efficacy of a unique pH-sensitive amphotericin B-loaded NLC (AmB-NLC) in Leishmania braziliensis infection in vitro and in vivo.

Methods and Results

AmB-NLC was assessed by dynamic light scattering and atomic force microscopy assays. The carrier showed a spherical shape with a nanometric size of 242.0 ± 18.3 nm. Zeta potential was suggestive of high carrier stability (−42.5 ± 1.5 mV), and the NLC showed ~99% drug encapsulation efficiency (EE%). In biological assays, AmB-NLC presented a similar IC₅₀ as free AmB and conventional AmB deoxycholate (AmB-D) (11.7 ± 1.73; 5.3 ± 0.55 and 13 ± 0.57 ng/mL, respectively), while also presenting higher selectivity index and lower toxicity to host cells, with no observed production of nitric oxide or TNF-α by in vitro assay. Confocal microscopy revealed the rapid uptake of AmB-NLC by infected macrophages after 1h, which, in association with more rapid disruption of AmB-NLC at acidic pH levels, may directly affect intracellular parasites. Leishmanicidal effects were evaluated in vivo in BALB/c mice infected in the ear dermis with L. braziliensis and treated with a pentavalent antimonial (Sb⁵⁺), liposomal AmB (AmB-L) or AmB-NLC. After 6 weeks of infection, AmB-NLC treatment resulted in smaller ear lesion size in all treated mice, indicating the efficacy of the novel formulation.

Conclusion

Here, we preliminarily demonstrate the effectiveness of an innovative and cost-effective AmB-NLC formulation in promoting the killing of intracellular L. braziliensis. This novel carrier system could be a promising alternative for the future treatment of cutaneous leishmaniasis.

Tailoring lipid nanoconstructs for the oral delivery of paliperidone: Formulation, optimization and in vitro evaluation

PURPOSE

The present research work involves Quality by Design (QbD)-based fabrication of lipid nanoconstructs (LNC) of paliperidone (PPD) bearing superior biopharmaceutical attributes.

METHODS

LNC of paliperidone was prepared by melt emulsification-probe sonication and high-pressure homogenization method followed by optimization using QbD approach. Preparing LNC by both these methods will give the benefit of identifying the best optimized formulation which will be further evaluated for in vitro studies.

RESULTS

The best optimized formulation was obtained using melt emulsification-probe sonication technique with small particle size (86.35 nm), high entrapment efficiency (90.07 %), and high loading capacity (8.49 %). The drug release from LNC was found to be 5, 8, and 9-folds greater than drug suspension in pH 1.2, 6.8, and 7.4 respectively (p < 0.001). Stability studies of LNC in simulated gastric fluid pH 1.2 and fasted state simulated intestinal fluid depicted no alteration in particle size and polydispersity index of LNC but were found to increase in fed state simulated intestinal fluid. The drug permeability through rat intestine for LNC was found to be approximately 6-folds (p < 0.05) greater as compared to the drug suspension which was further confirmed by confocal microscopy. The in vitro lipolysis study presented significantly highest solubilization (p < 0.001) in the aqueous phase thereby anticipating higher in vivo absorption.

CONCLUSION

Thus, it was concluded that LNC bears the knack of improving the solubilization and permeation potential of an otherwise hydrophobic drug, paliperidone."

Lipid-nanopotentiated combinatorial delivery of tamoxifen and sulforaphane: ex vivo, in vivo and toxicity studies

Aim: This study aims to load tamoxifen (TAM) and sulforaphane (SFN) into nanostructured lipid carriers (NLCs) to enhance their oral delivery. Materials & methods: TAM-SFN-NLCs were prepared using Precirol® ATO5 and Transcutol® HP, characterized and evaluated in vitro and ex vivo to assess the drug release profile and intestinal permeability, respectively. In vivo pharmacokinetic and acute toxicity assessment was performed in Wistar rats. Results: Optimized TAM-SFN-NLCs exhibited a particle size of 121.9 ± 6.42 nm and zeta potential of -21.2 ± 2.91 mV. The NLCs enhanced intestinal permeability of TAM and SFN and augmented oral bioavailability of TAM and SFN 5.2-fold and 4.8-fold, respectively. SFN significantly reduced TAM-associated toxicity in vivo. Conclusion: This coencapsulation of a chemotherapeutic agent with a herbal bioactive in NLCs could pave a novel treatment approach against cancer.

Rifabutin-Loaded Nanostructured Lipid Carriers as a Tool in Oral Anti-Mycobacterial Treatment of Crohn's Disease

Oral anti-mycobacterial treatment of Crohn's disease (CD) is limited by the low aqueous solubility of drugs, along with the altered gut conditions of patients, making uncommon their clinical use. Hence, the aim of the present work is focused on the in vitro evaluation of rifabutin (RFB)-loaded Nanostructured lipid carriers (NLC), in order to solve limitations associated to this therapeutic approach. RFB-loaded NLC were prepared by hot homogenization and characterized in terms of size, polydispersity, surface charge, morphology, thermal stability, and drug payload and release. Permeability across Caco-2 cell monolayers and cytotoxicity and uptake in human macrophages was also determined. NLC obtained were nano-sized, monodisperse, negatively charged, and spheroidal-shaped, showing a suitable drug payload and thermal stability. Furthermore, the permeability profile, macrophage uptake and selective intracellular release of RFB-loaded NLC, guarantee an effective drug dose administration to cells. Outcomes suggest that rifabutin-loaded NLC constitute a promising strategy to improve oral anti-mycobacterial therapy in Crohn's disease.

Docetaxel Loaded Pomegranate Seed Oil Based Nanostructured Lipid Carriers: A Potential Alternative to Current Formulation

The current work is focused on the development of docetaxel loaded pomegranate seed oil based lipid nanosystem. Docetaxel loaded pomegranate seed oil nanostructured lipid carriers (DTX-PSO-NLCs) were formulated by the melt emulsification method for parenteral delivery. The developed formulation was characterized in terms of their physicochemical parameters, solid-state characterization, in vitro drug release, in vitro cytotoxicity studies, and in vivo pharmacokinetics and biodistribution studies. Stability studies were carried out as per ICH guidelines Q1A. Melt emulsification method resulted in the formulation of stable DTX-PSO-NLCs with a particle size in the range of 150-180 nm and an entrapment efficiency of 63-65%. The in vitro release showed a slow and sustained release of the drug from the formulation compared to the marketed formulation (i.e., Daxotel®). The formulation was found to be stable for a period of 12 months at conditions of 4°C ± 2°C, 25°C ± 2°C/60% RH ± 5%RH, and 40°C ± 2°C/75% RH ± 5%RH. The developed nanosystem exhibited promising antitumor activity against various types of cancerous cell lines (i.e., MCF7, DU145, U87MG, and NCI-H460) relative to the marketed formulation. The pharmacokinetic evaluation revealed that DTX-PSO-NLCs had a better kinetic profile compared to the marketed formulation. Graphical abstract.

Bemotrizinol-Loaded Carnauba Wax-Based Nanostructured Lipid Carriers for Sunscreen: Optimization, Characterization, and In vitro Evaluation

Nanostructured lipid carriers (NLC) are aqueous dispersions of nanoparticles formed by solid and liquid lipids. In this study, NLC containing an organic UV filter, bemotrizinol, were developed for sunscreen formulation using carnauba wax and caprylic/capric triglycerides through ultrasonication technique. A Box-Behnken design was used to evaluate the influence of three variables on the particle size with the purpose of choosing the best system for further characterization. The particle size decreased as the surfactant concentration increased, reaching an average size of 122.4 ± 0.3 nm at 30 days of storage. Scanning electron microscopy showed intact and spherical particles. Thermal analysis and Fourier-transform infrared spectroscopy suggest that bemotrizinol was incorporated into the NLC. The X-ray diffraction showed a reduction in the crystallinity of the NLC. In vitro analysis indicated an improvement in the photoprotective activity of bemotrizinol when incorporated into NLC. These findings suggest a promising, stable, and biocompatible system.

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.

Ocular Inserts of Voriconazole-Loaded Proniosomal Gels: Formulation, Evaluation and Microbiological Studies

BACKGROUND

Voriconazole (VRC) is a triazole broad spectrum antifungal drug, used in the management of versatile fungal infections, particularly fungal keratitis. The obligatory use of niosomal delivery of VRC may reduce the frequency of dosing intervals resulting from its short biological half time and consequently improve patient compliance.

METHODS

VRC loaded proniosomes (VRC-PNs) were set by the coacervation technique and completely characterized. The developed formula was comprehensively assessed concerning in- vitro release behavior, kinetic investigation, and its conflict against refrigerated and room temperature conditions. A selected noisomal formula was incorporated into ocusert (VRC-PNs Ocu) formulated by 1% w/w hydroxypropyl methyl cellulose HPMC and 0.1% w/w carbopol 940. Eventually, in vitro antifungal activity against Candida albicans and Aspergillus nidulans was assessed by the cup diffusion method.

RESULTS

The optimized VRC-PNs (Pluronic F127: cholesterol weight ratio 1:1 w/w) exhibited the highest entrapment efficiency (87.4±2.55%) with a spherical shape, proper size in nano range and a suitable Zeta potential of 209.7±8.13 nm and -33.5±1.85 mV, respectively. Assurance of drug encapsulation in nanovesicles was accomplished by several means such as attenuated total reflection Fourier-transform infrared spectroscopy, differential scanning calorimetry in addition to powder X-ray diffraction investigations. It displayed a biphasic in vitro release pattern and after 6 months of storage at a refrigerated temperature, the optimized formula preserved its stability. VRC-PNs Ocu proved a very highly significant antifungal activity matched with the free drug or nanosuspension which was extra assured by comparing its mean inhibition zone with that of 5% natamycin market eye drops.

CONCLUSION

In conclusion, VRC-PNs Ocu could be considered as a promising stable sustained release topical ocular nanoparticulate system for the management of fungal infections.

An EGF- and Curcumin-Co-Encapsulated Nanostructured Lipid Carrier Accelerates Chronic-Wound Healing in Diabetic Rats

Nanostructured lipid carriers (NLC) are capable of encapsulating hydrophilic and lipophilic drugs. The present study developed an NLC containing epidermal growth factor (EGF) and curcumin (EGF–Cur-NLC). EGF–Cur-NLC was prepared by a modified water-in-oil-in-water (w/o/w) double-emulsion method. The EGF–Cur-NLC particles showed an average diameter of 331.8 nm and a high encapsulation efficiency (81.1% and 99.4% for EGF and curcumin, respectively). In vitro cell studies were performed using two cell types, NIH 3T3 fibroblasts and HaCaT keratinocytes. The results showed no loss of bioactivity of EGF in the NLC formulation. In addition, EGF–Cur-NLC improved in vitro cell migration, which mimics the wound healing process. Finally, EGF–Cur-NLC was evaluated in a chronic wound model in diabetic rats. We found that EGF–Cur-NLC accelerated wound closure and increased the activity of antioxidant enzymes. Overall, these results reveal the potential of the NLC formulation containing EGF and curcumin to promote healing of chronic wounds.

The in vivo toxicological profile of cationic solid lipid nanoparticles

Cationic solid lipid nanoparticles (cSLNs) are considered as one of the most effective lipid nanocarriers for delivery of low water-solubility compounds and genetic materials. As the excipients used in the cSLN production are generally regarded as safe (GRAS), the formulations are granted as non-toxic. However, the toxicological profile of new SLN-based formulations should always be performed to confirm that the delivery systems themselves may not impose risks to the human health. Therefore, in this study, we delineate the toxicological profile of the cSLN formulation at 24 and 72 h after single intravenous injection to male Wistar rats. Hematological, biochemical, and histopathological evaluations of the spleen, lungs, liver, and kidneys indicated short-lived alterations including neutrophilia. We found increases in the population of macrophages in the lungs, liver, and spleen and also migration of circulating neutrophils into inflamed tissue and a decrease in blood urea nitrogen. We also observed the presence of cSLNs within the brain parenchyma without any sign of damage to the blood-brain barrier. These side effects appeared to be mild and transitory (< 72 h). These findings reinforce the importance of investigating the toxicity of SLN-based formulations before the incorporation of drugs/genetic material to the formulation and its translation to the clinic.

Polymeric Nanoscale Drug Carriers Mediate the Delivery of Methotrexate for Developing Therapeutic Interventions Against Cancer and Rheumatoid Arthritis

Methotrexate (MTX) is widely used as an anticancer and anti-inflammtory drug for treating various types of cancer and autoimmune diseases. The optimal dose of MTX is known to inhibit the dihydrofolatereductase that hinders the replication of purines. The nanobiomedicine has been extensively explored in the past decade to develop myriad functional nanostructures to facilitate the delivery of therapeutic agents for various medical applications. This review is focused on understanding the design and development of MTX-loaded nanoparticles alongside the inclusion of recent findings for the treatment of cancers. In this paper, we have made a coordinated effort to show the potential of novel drug delivery systems by achieving effective and target-specific delivery of methotrexate.

Lidocaine-Loaded Solid Lipid Microparticles (SLMPs) Produced from Gas-Saturated Solutions for Wound Applications

The delivery of bioactive agents using active wound dressings for the management of pain and infections offers improved performances in the treatment of wound complications. In this work, solid lipid microparticles (SLMPs) loaded with lidocaine hydrochloride (LID) were processed and the formulation was evaluated regarding its ability to deliver the drug at the wound site and through the skin barrier. The SLMPs of glyceryl monostearate (GMS) were prepared with different LID contents (0, 1, 2, 4, and 10 wt.%) using the solvent-free and one-step PGSS (Particles from Gas-Saturated Solutions) technique. PGSS exploits the use of supercritical CO2 (scCO2) as a plasticizer for lipids and as pressurizing agent for the atomization of particles. The SLMPs were characterized in terms of shape, size, and morphology (SEM), physicochemical properties (ATR-IR, XRD), and drug content and release behavior. An in vitro test for the evaluation of the influence of the wound environment on the LID release rate from SLMPs was studied using different bioengineered human skin substitutes obtained by 3D-bioprinting. Finally, the antimicrobial activity of the SLMPs was evaluated against three relevant bacteria in wound infections (Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa). SLMPs processed with 10 wt.% of LID showed a remarkable performance to provide effective doses for pain relief and preventive infection effects.

Cutting-edge advances in therapy for the posterior segment of the eye: Solid lipid nanoparticles and nanostructured lipid carriers

Posterior segment eye diseases affect more than 300 million patients worldwide resulting in severe visual impairment. The treatments available are invasive, costly, present irregular effectiveness, and cause serious adverse effects. These drawbacks significantly reduce patient compliance. In the last decade, solid lipid nanoparticle (SLN) and nanostructured lipid carrier (NLC) have shown potential as innovative carriers for lipophilic drug substances to overcome hurdles in treating the eye posterior segment. This review shows the advantages of these formulations, focusing on their compatibility with ocular tissues, which increases the internalization of the drug substances. Additionally, SLN and NLC can reduce the clearance by the eye's protective mechanisms due to adhesive properties related to nanometric size. Therefore, these preparations may allow the treating of several ophthalmic diseases by topical administration, increasing the interval between doses. This feature can decrease adverse effects and enhance efficacy, ultimately improving patient compliance. Thus, this critical review presents the performance of the in vitro, ex vivo, and in vivo assays that support the potential of SLN and NLC to treat diseases of the posterior segment of the eye. These nanoparticles have shown to be promising alternative towards a major shift in developing ophthalmic products.

The preparation of lipid-based drug delivery system using melt extrusion

Melt extrusion of lipids is versatile with high applicability in the pharmaceutical industry. The formulations prepared can be easily customized depending on the requirements, and have the potential to open a window on personalized medicine.

Improved Transmucosal Delivery of Glimepiride via Unidirectional Release Buccal Film Loaded With Vitamin E TPGS-Based Nanocarrier

Glimepiride (GMD) is a hypoglycemic agent that has variation in bioavailability for its unexpected absorption. Glimepiride was formulated in a buccal film loaded with a nanobased formulation to enhance its absorption via buccal mucosa. Nanostructured lipid carriers (NLCs) and d-α-tocopherol polyethylene glycol 1000 succinate-based micelles enhance GMD solubility and improve its permeation through the buccal mucosa. The formulation variables were optimized using a Box-Behnken design. These factors, such as the percent of micelles relative to NLC (X₁), the percent of Carbopol (X₂), and the percent of permeation enhancer (X₃), were investigated for their effect on the initial release (Y₁) and the cumulative release after 6 hours (Y₂). The optimum levels for X₁, X₂, and X₃ were 100%, 0.05%, and 1.8%, respectively. The optimized formulation revealed that the permeation of GMD from the film was in favor of micelles. This optimized film was then coated with ethyl cellulose to direct the release only through the buccal mucosa. The optimized unidirectional GMD transmucosal film showed a release of 93.9% of GMD content at 6 hours compared to 60.41% of GMD release from the raw GMD film. This finding confirmed the suitability of transmucosal delivery of GMD via the buccal mucosa.

Double Optimization of Rivastigmine-Loaded Nanostructured Lipid Carriers (NLC) for Nose-to-Brain Delivery Using the Quality by Design (QbD) Approach: Formulation Variables and Instrumental Parameters

Rivastigmine is a drug commonly used in the management of Alzheimer's disease that shows bioavailability problems. To overcome this, the use of nanosystems, such as nanostructured lipid carriers (NLC), administered through alternative routes seems promising. In this work, we performed a double optimization of a rivastigmine-loaded NLC formulation for direct drug delivery from the nose to the brain using the quality by design (QbD) approach, whereby the quality target product profile (QTPP) was the requisite for nose to brain delivery. The experiments started with the optimization of the formulation variables (or critical material attributes-CMAs) using a central composite design. The rivastigmine-loaded NLC formulations with the best critical quality attributes (CQAs) of particle size, polydispersity index (PDI), zeta potential (ZP), and encapsulation efficiency (EE) were selected for the second optimization, which was related to the production methods (ultrasound technique and high-pressure homogenization). The most suitable instrumental parameters for the production of NLC were analyzed through a Box-Behnken design, with the same CQAs being evaluated for the first optimization. For the second part of the optimization studies, were selected two rivastigmine-loaded NLC formulations: one produced by ultrasound technique and the other by the high-pressure homogenization (HPH) method. Afterwards, the pH and osmolarity of these formulations were adjusted to the physiological nasal mucosa values and in vitro drug release studies were performed. The results of the first part of the optimization showed that the most adequate ratios of lipids and surfactants were 7.49:1.94 and 4.5:0.5 (%, w/w), respectively. From the second part of the optimization, the results for the particle size, PDI, ZP, and EE of the rivastigmine-loaded NLC formulations produced by ultrasound technique and HPH method were, respectively, 114.0 ± 1.9 nm and 109.0 ± 0.9 nm; 0.221 ± 0.003 and 0.196 ± 0.007; -30.6 ± 0.3 mV and -30.5 ± 0.3 mV; 97.0 ± 0.5% and 97.2 ± 0.3%. Herein, the HPH was selected as the most suitable production method, although the ultrasound technique has also shown effectiveness. In addition, no significant changes in CQAs were observed after 90 days of storage of the formulations at different temperatures. In vitro studies showed that the release of rivastigmine followed a non-Fickian mechanism, with an initial fast drug release followed by a prolonged release over 48 h. This study has optimized a rivastigmine-loaded NLC formulation produced by the HPH method for nose-to-brain delivery of rivastigmine. The next step is for in vitro and in vivo experiments to demonstrate preclinical efficacy and safety. QbD was demonstrated to be a useful approach for the optimization of NLC formulations for which specific physicochemical requisites can be identified.

A promising approach to develop nanostructured lipid carriers from solid lipid nanoparticles: preparation, characterization, cytotoxicity and nucleic acid binding ability

We aimed to develop nanostructured lipid carriers (NLCs) displaying similar characteristics - particle size, polydispersity index, and zeta potential - with the model solid lipid nanoparticles (SLNs) for better comparability. By considering the hydrophilic-lipophilic balance values of solid and liquid lipids, five out of six NLCs and eight out of eight cationic NLCs (cNLCs) were successfully prepared with similar characteristics to their precursor SLN and cationic SLNs (cSLNs), respectively. Among cationic formulations, two cSLNs containing different surfactant/co-surfactant concentrations (4% and 8% S/CoS; w/w) and their cNLC versions prepared with Labrafac lipophile WL 1349 (LWL) or Labrafac PG were selected to compare cytotoxicity, stability, and nucleic acid binding ability. All formulations are well-tolerated by L-929 cells, cSLNs being least toxic. The formulations containing 4% S/CoS had higher stability after 24-months. All nanoparticles formed complexes with pDNA (Binding ability: cNLCs > cSLNs). cSLN and LWL-cNLC containing 4% S/CoS showed the highest pDNA binding capacity in each group, and their spherical/oval shape was revealed by electron microscopy. However, they did not form complexes with siRNA. The developed approach has the potential to simplify the production of (c)NLCs having similar physicochemical properties with the optimum (c)SLN and may provide better insight for (c)SLN vs.

Omar M, A. Mahmoud H, A. Abou-Taleb H. Nanostructured Lipid Carriers to Mediate Brain Delivery of Temazepam: Design and In Vivo Study

The opposing effect of the blood–brain barrier against the delivery of most drugs warrants the need for an efficient brain targeted drug delivery system for the successful management of neurological disorders. Temazepam-loaded nanostructured lipid carriers (NLCs) have shown possibilities for enhancing bioavailability and brain targeting affinity after oral administration. This study aimed to investigate these properties for insomnia treatment. Temazepam-NLCs were prepared by the solvent injection method and optimized using a 4² full factorial design. The optimum formulation (NLC-1) consisted of; Compritol^® 888 ATO (75 mg), oleic acid (25 mg), and Poloxamer^® 407 (0.3 g), with an entrapment efficiency of 75.2 ± 0.1%. The average size, zeta potential, and polydispersity index were determined to be 306.6 ± 49.6 nm, −10.2 ± 0.3 mV, and 0.09 ± 0.10, respectively. Moreover, an in vitro release study showed that the optimized temazepam NLC-1 formulation had a sustained release profile. Scintigraphy images showed evident improvement in brain uptake for the oral ^99mTc-temazepam NLC-1 formulation versus the ^99mTc-temazepam suspension. Pharmacokinetic data revealed a significant increase in the relative bioavailability of ^99mTc-temazepam NLC-1 formulation (292.7%), compared to that of oral ^99mTc-temazepam suspension. Besides, the NLC formulation exhibited a distinct targeting affinity to rat brain. In conclusion, our results indicate that the developed temazepam NLC formulation can be considered as a potential nanocarrier for brain-mediated drug delivery in the out-patient management of insomnia.

Pumpkin Oil-Based Nanostructured Lipid Carrier System for Antiulcer Effect in NSAID-Induced Gastric Ulcer Model in Rats

Background

Peptic ulcer disease, a painful lesion of the gastric mucosa, is considered one of the most common gastrointestinal disorders. This study aims to investigate the formulation of pumpkin seed oil (PSO)-based nanostructured lipid carriers (NLCs) to utilize PSO as the liquid lipid component of NLCs and to achieve oil dispersion in the nano-range in the stomach.

Methods

Box–Behnken design was utilized to deduce the optimum formula with minimum particle size. The optimized PSO-NLCs formula was investigated for gastric ulcer protective effects in Wistar rats by evaluating ulcer index and determination of gastric mucosa oxidative stress parameters.

Results

PSO was successfully incorporated as the liquid lipid (LL) component of NLCs. The prepared optimum PSO-NLCs formula showed a size of 64.3 nm. Pretreatment of animals using the optimized PSO-NLCs formula showed significantly (p< 0.001) lower ulcer index compared to indomethacin alone group and significantly (p<0.05) less mucosal lesions compared to the raw oil.

Conclusion

These results indicated great potential for future application of optimized PSO-NLCs formula for antiulcer effect in non-steroidal anti-inflammatory drug (NSAID)-induced gastric ulcer.

A Correlative Imaging Study of in vivo and ex vivo Biodistribution of Solid Lipid Nanoparticles

Purpose

Solid lipid nanoparticles are largely used in biomedical research and are characterized by high stability and biocompatibility and are also able to improve the stability of various loaded molecules. In vitro studies demonstrated that these nanoparticles are low cytotoxic, while in vivo studies proved their efficiency as nanocarriers for molecules characterized by a low bioavailability. However, to our knowledge, no data on the systemic biodistribution and organ accumulation of solid lipid nanoparticles in itself are presently available.

Methods

In this view, we investigated the solid lipid nanoparticles biodistribution by a multimodal imaging approach correlating in vivo and ex vivo analyses. We loaded solid lipid nanoparticles with two different fluorophores (cardiogreen and rhodamine) to observe them with an optical imager in the whole organism and in the excised organs, and with fluorescence microscopy in tissue sections. Light and transmission electron microscopy analyses were also performed to evaluate possible structural modification or damage due to nanoparticle administration.

Results

Solid lipid nanoparticles loaded with the two fluorochromes showed good optic characteristics and stable polydispersity. After in vivo administration, they were clearly detectable in the organism. Four  hours after the injection, the fluorescent signal occurred in anatomical districts corresponding to the liver and this was confirmed by the ex vivo acquisitions of excised organs. Brightfield, fluorescence and transmission electron microscopy confirmed solid lipid nanoparticles accumulation in hepatocytes without structural damage.

Conclusion

Our results support the systemic biocompatibility of solid lipid nanoparticles and demonstrate their detailed biodistribution from the whole organism to organs until the cells.

Nanostructured Lipid Carriers for Delivery of Chemotherapeutics: A Review

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

Multifunctional nanomedicines for targeting epidermal growth factor receptor in colorectal cancer

Systemic administration of chemotherapeutics by nanocarriers (NCs) functionalized with targeting agents provides a localized accumulation of drugs in the target tissues and cells. Advanced nanoscaled medicaments can enter into the tumor microenvironment (TME) and overcome the uniquely dysregulated biological settings of TME, including highly pressurized tumor interstitial fluid in an acidic milieu. Such multimodal nanomedicines seem to be one of the most effective treatment modalities against solid tumors such as colorectal cancer (CRC). To progress and invade, cancer cells overexpress various oncogenes and molecular markers such as epidermal growth factor receptors (EGFRs), which can be exploited for targeted delivery of nanoscaled drug delivery systems (DDSs). In fact, to develop effective personalized multimodal nanomedicines, the type of solid tumor and status of the disease in each patient should be taken into consideration. While the development of such multimodal-targeted nanomedicines is largely dependent on the expression level of oncomarkers, the type of NCs and homing/imaging agents play key roles in terms of their efficient applications. In this review, we provide deep insights into the development of EGFR-targeting nanomedicines and discuss various types of nanoscale DDSs (e.g., organic and inorganic nanoparticles) for targeting of the EGFR-positive solid tumors such as CRC.

Self-assembly of Organic Nanomaterials and Biomaterials: The Bottom-Up Approach for Functional Nanostructures Formation and Advanced Applications

In this paper, we survey recent advances in the self-assembly processes of novel functional platforms for nanomaterials and biomaterials applications. We provide an organized overview, by analyzing the main factors that influence the formation of organic nanostructured systems, while putting into evidence the main challenges, limitations and emerging approaches in the various fields of nanotechology and biotechnology. We outline how the building blocks properties, the mutual and cooperative interactions, as well as the initial spatial configuration (and environment conditions) play a fundamental role in the construction of efficient nanostructured materials with desired functional properties. The insertion of functional endgroups (such as polymers, peptides or DNA) within the nanostructured units has enormously increased the complexity of morphologies and functions that can be designed in the fabrication of bio-inspired materials capable of mimicking biological activity. However, unwanted or uncontrollable effects originating from unexpected thermodynamic perturbations or complex cooperative interactions interfere at the molecular level with the designed assembly process. Correction and harmonization of unwanted processes is one of the major challenges of the next decades and requires a deeper knowledge and understanding of the key factors that drive the formation of nanomaterials. Self-assembly of nanomaterials still remains a central topic of current research located at the interface between material science and engineering, biotechnology and nanomedicine, and it will continue to stimulate the renewed interest of biologist, physicists and materials engineers by combining the principles of molecular self-assembly with the concept of supramolecular chemistry.

SLN and NLC for topical, dermal, and transdermal drug delivery

Introduction: From a biopharmaceutical standpoint, the skin is recognized as an interesting route for drug delivery. In general, small molecules are able to penetrate the stratum corneum, the outermost layer of the skin. In contrast, the delivery of larger molecules, such as peptides and proteins, remains a challenge. Nanoparticles have been exploited not only to enhance skin penetration of drugs but also to expand the range of molecules to be clinically used.Areas covered: This review focus on Solid lipid nanoparticles (SLN) and Nanostructured lipid carriers (NLC) for skin administration. We discuss the selection criteria for lipids, surfactants, and surface modifiers commonly in use in SLN/NLC, their production techniques, and the range of drugs loaded in these lipid nanoparticles for the treatment of skin disorders.Expert opinion: Depending on the lipid and surfactant composition, different nanoparticle morphologies can be generated. Both SLN and NLC are composed of lipids that resemble those of the skin and sebum, which contribute to their enhanced biocompatibility, with limited toxicological risk. SLN and NLC can be loaded with very chemically different drugs, may provide a tunable release profile, can be produced in a sterilized environment, and be scaled-up without the need for organic solvents.

Recent strategies and advances in the fabrication of nano lipid carriers and their application towards brain targeting

In last two decades, the lipid nanocarriers have been extensively investigated for their drug targeting efficiency towards the critical areas of the human body like CNS, cardiac region, tumor cells, etc. Owing to the flexibility and biocompatibility, the lipid-based nanocarriers, including nanoemulsion, liposomes, SLN, NLC etc. have gained much attention among various other nanocarrier systems for brain targeting of bioactives. Across different lipid nanocarriers, NLC remains to be the safest, stable, biocompatible and cost-effective drug carrier system with high encapsulation efficiency. Drug delivery to the brain always remains a challenging issue for scientists due to the complex structure and various barrier mechanisms surrounding the brain. The application of a suitable nanocarrier system and the use of any alternative route of drug administration like nose-to-brain drug delivery could overcome the hurdle and improves the therapeutic efficiency of CNS acting drugs thereof. NLC, a second-generation lipid nanocarrier, upsurges the drug permeation across the BBB due to its unique structural properties. The biocompatible lipid matrix and nano-size make it an ideal drug carrier for brain targeting. It offers many advantages over other drug carrier systems, including ease of manufacturing and scale-up to industrial level, higher drug targeting, high drug loading, control drug release, compatibility with a wide range of drug substances, non-toxic and non-irritant behavior. This review highlights recent progresses towards the development of NLC for brain targeting of bioactives with particular reference to its surface modifications, formulations aspects, pharmacokinetic behavior and efficacy towards the treatment of various neurological disorders like AD, PD, schizophrenia, epilepsy, brain cancer, CNS infection (viral and fungal), multiple sclerosis, cerebral ischemia, and cerebral malaria. This work describes in detail the role and application of NLC, along with its different fabrication techniques and associated limitations. Specific emphasis is given to compile a summary and graphical data on the area explored by scientists and researchers worldwide towards the treatment of neurological disorders with or without NLC. The article also highlights a brief insight into two prime approaches for brain targeting, including drug delivery across BBB and direct nose-to-brain drug delivery along with the current global status of specific neurological disorders.

Curcumin's Nanomedicine Formulations for Therapeutic Application in Neurological Diseases

The brain is the body's control center, so when a disease affects it, the outcomes are devastating. Alzheimer's and Parkinson's disease, and multiple sclerosis are brain diseases that cause a large number of human deaths worldwide. Curcumin has demonstrated beneficial effects on brain health through several mechanisms such as antioxidant, amyloid β-binding, anti-inflammatory, tau inhibition, metal chelation, neurogenesis activity, and synaptogenesis promotion. The therapeutic limitation of curcumin is its bioavailability, and to address this problem, new nanoformulations are being developed. The present review aims to summarize the general bioactivity of curcumin in neurological disorders, how functional molecules are extracted, and the different types of nanoformulations available.

Progress and perspectives of brain-targeting lipid-based nanosystems via the nasal route in Alzheimer's disease

Since health care systems dedicate substantial resources to Alzheimer's disease (AD), it poses an increasing challenge to scientists and health care providers worldwide, especially that many decades of research in the medical field revealed no optimal effective treatment for this disease. The intranasal administration route seems to be a preferable route of anti-AD drug delivery over the oral one as it demonstrates an ability to overcome the related obstacles reflected in low bioavailability, limited brain exposure and undesired pharmacokinetics or side effects. This delivery route can bypass the systemic circulation through the intraneuronal and extraneuronal pathways, providing truly needleless and direct brain drug delivery of the therapeutics due to its large surface area, porous endothelial membrane, the avoidance of the first-pass metabolism, and ready accessibility. Among the different nano-carrier systems developed, lipid-based nanosystems have become increasingly popular and have proven to be effective in managing the common symptoms of AD when administered via the nose-to-brain delivery route, which provides an answer to circumventing the BBB. The design of such lipid-based nanocarriers could be challenging since many factors can contribute to the quality of the final product. Hence, according to the authors, it is recommended to follow the quality by design methodology from the early stage of development to ensure high product quality while saving efforts and costs. This review article aims to draw attention to the up-to-date findings in the field of lipid-based nanosystems and the potential role of developing such forms in the management of AD by means of the nose-to-brain delivery route, in addition to highlighting the significant role of applying QbD methodology in this development.

Lipid Nanocarriers for Enhanced Delivery of Temozolomide to the Brain

Brain disorders, a diverse range of conditions comprising of neurological and psychiatric conditions, are the leading cause of disability, severely affect the quality of life, and in many cases lead to mortality. The prime challenge in treatment of brain disorders is to deliver therapeutics by overcoming the blood-brain barrier (BBB), a unique anatomical and physiological barrier which restricts the passage of a number of molecules, proteins, and cells from the bloodstream. Lipid nanoparticles have emerged as promising drug delivery systems primarily because of biodegradability, low toxicity potential, and the ability to cross physiological barriers especially the BBB even without surface modifications.In this chapter we discuss the preparation and characterization of nanostructured lipid carriers of temozolomide, a chemotherapeutic drug. Evaluation of pharmacokinetics and biodistribution of the nanocarrier system in rats revealed improved delivery of the chemotherapeutic agent to the brain with the potential of lesser side effects.

Key for crossing the BBB with nanoparticles: the rational design

Central nervous system diseases are a heavy burden on society and health care systems. Hence, the delivery of drugs to the brain has gained more and more interest. The brain is protected by the blood-brain barrier (BBB), a selective barrier formed by the endothelial cells of the cerebral microvessels, which at the same time acts as a bottleneck for drug delivery by preventing the vast majority of drugs to reach the brain. To overcome this obstacle, drugs can be loaded inside nanoparticles that can carry the drug through the BBB. However, not all particles are able to cross the BBB and a multitude of factors needs to be taken into account when developing a carrier system for this purpose. Depending on the chosen pathway to cross the BBB, nanoparticle material, size and surface properties such as functionalization and charge should be tailored to fit the specific route of BBB crossing.

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

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

Design and Optimization of Nanostructured Lipid Carrier Containing Dexamethasone for Ophthalmic Use

The aim of this study was to perform a preformulation study of dexamethasone (DXM)-loaded nanostructured lipid carriers (NLCs) for ocular use. Lipid screening was applied to find the most suitable solid and liquid lipids and surfactant for the NLC formulation. The visual observation was proved with XRD measurements for the establishment of the soluble state of DXM. Thermoanalytical measurements indicated that the most relevant depression of the crystallinity index could be ensured when using a 7:3 solid lipid:oil ratio. In order to optimize the NLC composition, a 2³ full factorial experimental design was used. It was established that each independent factor (lipid, DXM, and surfactant concentration) had a significant effect on the particle size while in the case of entrapment efficiency, the DXM and surfactant concentrations were significant. Lower surfactant and lipid concentrations could be beneficial because the stability and the entrapment efficacy of NLCs were more favorable. The toxicity tests on human cornea cells indicated good ophthalmic tolerability of NLCs. The in vitro drug release study predicted a higher concentration of the solute DXM on the eye surface while the Raman mapping penetration study on the porcine cornea showed a high concentration of nanocarriers in the hydrophylic stroma layer.

Lipid Nanoparticles and Active Natural Compounds: A Perfect Combination for Pharmaceutical Applications

Phytochemicals represent an important class of bioactive compounds characterized by significant health benefits. Notwithstanding these important features, their potential therapeutic properties suffer from poor water solubility and membrane permeability limiting their approach to nutraceutical and pharmaceutical applications. Lipid nanoparticles are well known carrier systems endowed with high biodegradation and an extraordinary biocompatible chemical nature, successfully used as platform for advanced delivery of many active compounds, including the oral, topical and systemic routes. This article is aimed at reviewing the last ten years of studies about the application of lipid nanoparticles in active natural compounds reporting examples and advantages of these colloidal carrier systems.

Tamoxifen and Sulphoraphane for the breast cancer management: A synergistic nanomedicine approach

Breast cancer is second most leading cause of death in all over the world and not only limited to the females. Tamoxifen has been considered as the gold line therapy for estrogen receptor positive breast cancer. However, this chemopreventive approach has been focused at individuals in high risk group and limits its clinical applications to moderate and/or lower risk groups. Moreover, Tamoxifen treatment is associated with a dose related hepatotoxicity and nephrotoxicity and eventually results in poor quality of life of patients. Sulphoraphane, a naturally occurring isothiocyanate derivative has been investigated for its numerous potential biological activities including anticancer effects. The present hypothesis aims to put forward in which Tamoxifen is combined with a natural bioactive Sulphoraphane, both incorporated into a novel lipid based nanocarrier at a reduced dose, which would eventually shuttle the cargo to the target site. At the breast cancer, Sulphoraphane sensitizes the estrogen receptors and ameliorates the binding affinity of Tamoxifen to these receptors, thereby potentiating the anticancer efficacy and reducing the offsite toxicity of Tamoxifen. This dual loaded zero-dimension lipid carrier would be a value addition to the current treatment regimen for breast cancer management.

Preparation and Properties of Semi-Self-Assembled Lipopeptide Vesicles

Novel lipopeptide vesicles are prepared from self-assembled nanomembranes through an extrusion method. The size of vesicles can be controlled by the pore diameter of the extrusion filter. The vesicles are rather stable because hydrogen bonds exist among the peptide headgroups. When doxorubicin hydrochloride (DOX·HCl) is encapsulated in the vesicles, it could be released sustainably, and its side effect would also be reduced due to encapsulation. The leakage rate of DOX·HCl depends on the pH via charge regulation. As drug carriers, lipopeptide vesicles have been proved to have nontoxicity to normal cells. A magnetic surfactant CH₃(CH₂)₁₄CH₂N(CH₃)₃⁺ [FeCl₃Br]^- (CTAFe) was mixed with lipopeptide to modify the vesicles. Also, the results demonstrated that the vesicles is endowed with magnetic property after the addition of CTAFe. We believe that the strategy of lipopeptide vesicle preparation would enrich the drug carrier family and expand the application of lipopeptide materials.