Solid lipid nanoparticles

A study to enhance the oral bioavailability of s-adenosyl-l-methionine (SAMe): SLN and SLN nanocomposite particles

The endogenous molecule, S-adenosyl-l-methionine (SAMe) is a key factor due to its role in the methylation cycle and modulation of monoaminergic neurotransmission. Since many mental disorders have linked to the monoaminergic system, the level of SAMe in blood and cerebrospinal fluid is important in the treatment of major depression. In this study, solid lipid nanoparticles (SLN) were prepared in order to increase the limited oral bioavailability of SAMe, and SLN based nanocomposite particles (SAMe-SLN-NC) were further developed using an enteric polymer for passive targeting of intestinal lymphatic system. In this manner, it was also aimed to protect SAMe loaded SLN from harsh gastric environment as well as hepatic first-pass metabolism. Dynamic light scattering (DLS) analysis of SLN was performed, drug content was measured, SAMe release patterns were examined and the permeation ability of SAMe was investigated by the Parallel Artificial Membrane Permeability Assay (PAMPA) to characterize SAMe loaded SLN formulation. According to the PAMPA results, SAMe-SLN with the average particle size of 242 nm showed enhanced SAMe permeability in comparison to pure drug. Delayed drug release obtained by SLN nanocomposite particles indicated the protection of drug-loaded SLN in the acidic gastric medium and their intact presence in the intestine. SAMe solution or particle suspensions were prepared using 0.45 (w/v) hydroxypropyl methylcellulose aqueous solution to be applied to groups of animals for pharmacokinetic studies. In vivo pharmacokinetic parameters revealed enhancement in relative bioavailability of SAMe upon oral administration of SLN based formulations. This was attributed to intact absorption of lipid matrix through lymphatic path. A statistically significant increase in SAMe plasma levels was obtained at 15th and 30th minutes with SAMe-SLN and at 2nd and 4th hours with SAMe-SLN-NC. Overall results suggest that SLN is a promising carrier to passive lymphatic targeting of SAMe and novel SLN nanocomposite particles which presented efficient oral bioavailability is a potential way for oral delivery of SAMe and treatment of major depression.

Lipid Nanoparticles as Carriers for Bioactive Delivery

Nanotechnology has made a great impact on the pharmaceutical, biotechnology, food, and cosmetics industries. More than 40% of the approved drugs are lipophilic and have poor solubility. This is the major rate-limiting step that influences the release profile and bioavailability of drugs. Several approaches have been reported to administer lipophilic drugs with improved solubility and bioavailability. Nanotechnology plays a crucial role in the targeted delivery of poorly soluble drugs. Nanotechnology-based drug delivery systems can be classified as solid lipid nanoparticulate drug delivery systems, emulsion-based nanodrug delivery systems, vesicular drug delivery systems, etc. Nanotechnology presents a new frontier in research and development to conquer the limitations coupled with the conventional drug delivery systems through the formation of specific functionalized particles. This review presents a bird's eye view on various aspects of lipid nanoparticles as carriers of bioactive molecules that is, synthesis, characterization, advantage, disadvantage, toxicity, and application in the medical field. Update on recent development in terms of patents and clinical trials of solid lipid nanoparticles (SLNs) and nanostructure lipid carriers (NLCs) have also been discussed in this article.

Nanotechnology based solutions for anti-leishmanial impediments: a detailed insight

As a neglected tropical disease, Leishmaniasis is significantly instigating morbidity and mortality across the globe. Its clinical spectrum varies from ulcerative cutaneous lesions to systemic immersion causing hyperthermic hepato-splenomegaly. Curbing leishmanial parasite is toughly attributable to the myriad obstacles in existing chemotherapy and immunization. Since the 1990s, extensive research has been conducted for ameliorating disease prognosis, by resolving certain obstacles of conventional therapeutics viz. poor efficacy, systemic toxicity, inadequate drug accumulation inside the macrophage, scarce antigenic presentation to body's immune cells, protracted length and cost of the treatment. Mentioned hurdles can be restricted by designing nano-drug delivery system (nano-DDS) of extant anti-leishmanials, phyto-nano-DDS, surface modified-mannosylated and thiolated nano-DDS. Likewise, antigen delivery with co-transportation of suitable adjuvants would be achievable through nano-vaccines. In the past decade, researchers have engineered nano-DDS to improve the safety profile of existing drugs by restricting their release parameters. Polymerically-derived nano-DDS were found as a suitable option for oral delivery as well as SLNs due to pharmacokinetic re-modeling of drugs. Mannosylated nano-DDS have upgraded macrophage internalizing of nanosystem and the entrapped drug, provided with minimal toxicity. Cutaneous Leishmaniasis (CL) was tackling by the utilization of nano-DDS designed for topical delivery including niosomes, liposomes, and transfersomes. Transfersomes, however, appears to be superior for this purpose. The nanotechnology-based solution to prevent parasitic resistance is the use of Thiolated drug-loaded and multiple drugs loaded nano-DDS. These surfaces amended nano-DDS possess augmented IC50 values in comparison to conventional drugs and un-modified nano-DDS. Phyto-nano-DDS, another obscure horizon, have also been evaluated for their anti-leishmanial response, however, more intense assessment is a prerequisite. Impoverished Cytotoxic T-cells response followed by Leishmanial antigen proteins delivery have also been vanquished using nano-adjuvants. The eminence of nano-DDS for curtailment of anti-leishmanial chemotherapy and immunization associated challenges are extensively summed up in this review. This expedited approach is ameliorating the Leishmaniasis management successfully. Alongside, total to partial eradication of this disease can be sought along with associated co-morbidities.

Application of solid lipid nanoparticles as a long-term drug delivery platform for intramuscular and subcutaneous administration: In vitro and in vivo evaluation

The purpose of this work was to evaluate solid lipid nanoparticles (SLNs) as a long acting injectable drug delivery platform for intramuscular and subcutaneous administration. SLNs were developed with a low (unsaturated) and high (supersaturated) drug concentration at equivalent lipid doses. The impact of the drug loading as well as the administration route for the SLNs using two model compounds with different physicochemical properties were explored for their in vitro and in vivo performance. Results revealed that drug concentration had an influence on the particle size and entrapment efficiency of the SLNs and, therefore, indirectly an influence on the C_max/dose and AUC/dose after administration to rats. Furthermore, the in vitro drug release was compound specific, and linked to the affinity of the drug compounds towards the lipid matrix and release medium. The pharmacokinetic parameters resulted in an increased t_max, t_1/2 and mean residence time (MRT) for all formulations after intramuscular and subcutaneous dosing, when compared to intravenous administration. Whereas, the subcutaneous injections performed better for those parameters than the intramuscular injections, because of the higher blood perfusion in the muscles compared with the subcutaneous tissues. In conclusion, SLNs extend drug release, need to be optimized for each drug, and are appropriate carriers for the delivery of drugs that require a short-term sustained release in a timely manner.

Co-delivery of hesperidin and clarithromycin in a nanostructured lipid carrier for the eradication of Helicobacter pylori in vitro

Effective and precise eradication of Helicobacter pylori (H. pylori) is the most promising approach to avoid H. pylori-related gastrointestinal disorders. The present study was conducted to demonstrate the efficacy of the co-delivery of hesperidin (Hesp) and clarithromycin (CLR) in nanostructured lipid carriers (NLCs) against H. pylori. We have produced a new delivery system by combining bioflavonoid Hesp and CLR NLCs to address the failure in single antibiotic therapies. Briefly, a blend of solid lipid, liquid lipid, and surfactant was used. Homogeneous NLCs with all the formulations showed a nano size and surface-negative charge and presented high in vitro stability and slow release of the drug even after 24 h. Bioimaging studies by scanning electron microscopy, transmission electron microscopy, and imaging flow cytometry indicated that NLCs interacted with the membrane by adhering to the outer cell membrane and disrupted the membrane that resulted in the leakage of cytoplasmic contents. The prepared NLCs provide sustained and controlled drug release that can be used to increase the rate of H. pylori eradication.

Downregulation of MMP1 expression mediates the anti-aging activity of Citrus sinensis peel extract nanoformulation in UV induced photoaging in mice

Aging of the skin is a complicated bioprocess that is affected by constant exposure to ultraviolet irradiation. The application of herbal-based anti-aging creams is still the best choice for treatment. In the present study, Citrus sinensis L. fruit peels ethanolic extract (CSPE) was formulated into lipid nanoparticles (LNPs) anti-aging cream. Eight different formulations of CSEP-LNPs were prepared and optimized using 2³ full factorial designs. In vivo antiaging effect of the best formula was tested in Swiss albino mice where photo-aging was induced by exposure to UV radiation. HPLC-QToF-MS/MS metabolic profiling of CSPE led to the identification of twenty-nine metabolites. CSPE was standardized to a hesperidin content of 15.53 ± 0.152 mg% using RP-HPLC. It was suggested that the optimized formulation (F7) had (245 nm) particle size, (91.065%) EE, and (91.385%) occlusive effect with a spherical and smooth surface. The visible appearance of UV-induced photoaging in mice was significantly improved after topical application on CSPE-NLC cream for 5 weeks, levels of collagen and SOD were significantly increased in CSPE- NLC group, while levels of PGE2, COX2, JNK, MDA, and elastin was reduced. Finally, The prepared anti-aging CSPE-NLC cream represents a safe, convenient, and promising skincare cosmetic product.

Efficiency of Deoxynivalenol Detoxification by Microencapsulated Sodium Metabisulfite Assessed via an In Vitro Bioassay Based on Intestinal Porcine Epithelial Cells

Deoxynivalenol (DON) contamination occurs in feeds and causes a reduction in growth performance, damage to the intestinal epithelial cells, and increased susceptibility to enteric pathogen challenge. Sodium metabisulfite (SMBS) has shown promise in reducing DON; however, SMBS quickly degrades under aqueous acidic conditions such as the environment within a stomach. Thus, protection of SMBS is required for effective delivery to the small intestine to detoxify DON. This study was to encapsulate SMBS into hydrogenated palm oil-based microparticles for its delivery to the small intestine and to evaluate its efficacy on DON detoxification in simulated intestinal fluids using IPEC-J2 cells in vitro. The diameter of the SMBS containing microparticles was 511 ± 135 μm, and the loading capacity of SMBS in the microparticles was 45.50%; 1.41% of the encapsulated SMBS (ES) was released into the simulated gastric fluid, and 66.39% of ES was progressively released into the simulated intestinal fluid within 4 h at 37 °C. In IPEC-J2 cells, when DON was treated with the simulated gastric fluid containing 0.5% ES for 2 h, then mixed with the simulated intestinal fluid (1:1) and incubated for 2 h, cytotoxicity was not observed. DON treated with 0.5 ES decreased the gene expression of inflammatory cytokines in the cells compared with DON alone and maintained the cell integrity. To conclude, the SMBS containing microparticles were stable in the simulated gastric fluid and allowed a progressive release of SMBS in the simulated intestinal fluid. The released SMBS in the simulated intestinal fluid effectively detoxified DON.

Size shifting of solid lipid nanoparticle system triggered by alkaline phosphatase for site specific mucosal drug delivery

We aim to prepare a size-shifting nanocarrier for site-targeting mucosal drug delivery that can penetrate through mucus gel layer and remain close to the absorption membrane. As nanocarriers can be engineered to penetrate mucus but they can also back diffuse into outer mucus regions, a size shifting to micron range once they have reached the absorption membrane would prevent back-diffusion effect and extend drug release over a long period of time. For this purpose, we loaded solid lipid nanoparticles (SLN) with a phosphate ester surfactant and octadecylamine. Alkaline phosphatase (AP), a membrane bound enzyme was for the first time utilized as an in situ partner for triggering the size conversion at epithelial cell surface. Having the size of ~120 nm, SLN with hydrophilic and phosphate-decorated shells were shown to penetrate through mucus gel and form aggregates above cell layer surface. Aggregates of 5-8 µm were formed due to interparticle interactions induced by enzymatic phosphate removal after ~30 min in contact with isolated AP. The developed SLN system could be a potential tool for mucosal drug delivery to AP-expressing tissues like colon, lung, cervix, vagina and some mucus-secreting tumors.

Plant oils: From chemical composition to encapsulated form use

The last decade has witnessed a burgeoning global movement towards essential and vegetable oils in the food, agriculture, pharmaceutical, cosmetic, and textile industries thanks to their natural and safe status, broad acceptance by consumers, and versatile functional properties. However, efforts to develop new therapy or functional agents based on plant oils have met with challenges of limited stability and/or reduced efficacy. As a result, there has been increased research interest in the encapsulation of plant oils, whereby the nanocarriers serve as barrier between plant oils and the environment and control oil release leading to improved efficacy, reduced toxicity and enhanced patient compliance and convenience. In this review, special concern has been addressed to the encapsulation of essential and vegetable oils in three types of nanocarriers: polymeric nanoparticles, liposomes and solid lipid nanoparticles. First, the chemical composition of essential and vegetable oils was handled. Moreover, we gather together the research findings reported by the literature regarding the different techniques used to generate these nanocarriers with their significant findings. Finally, differences and similarities between these nanocarriers are discussed, along with current and future applications that are warranted by their structures and properties.

Lipid-Based Nanocarriers for Ophthalmic Administration: Towards Experimental Design Implementation

Nanotherapeutics based on biocompatible lipid matrices allow for enhanced solubility of poorly soluble compounds in the treatment of ophthalmic diseases, overcoming the anatomical and physiological barriers present in the eye, which, despite the ease of access, remains strongly protected. Micro-/nanoemulsions, solid lipid nanoparticles (SLN) or nanostructured lipid carriers (NLC) combine liquid and/or solid lipids with surfactants, improving drug stability and ocular bioavailability. Current research and development approaches based on try-and-error methodologies are unable to easily fine-tune nanoparticle populations in order to overcome the numerous constraints of ocular administration routes, which is believed to hamper easy approval from regulatory agencies for these systems. The predictable quality and specifications of the product can be achieved through quality-by-design (QbD) implementation in both research and industrial environments, in contrast to the current quality-by-testing (QbT) framework. Mathematical modelling of the expected final nanoparticle characteristics by variation of operator-controllable variables of the process can be achieved through adequate statistical design-of-experiments (DoE) application. This multivariate approach allows for optimisation of drug delivery platforms, reducing research costs and time, while maximising the understanding of the production process. This review aims to highlight the latest efforts in implementing the design of experiments to produce optimised lipid-based nanocarriers intended for ophthalmic administration. A useful background and an overview of the different possible approaches are presented, serving as a starting point to introduce the design of experiments in current nanoparticle research.

Mosquito-repellent controlled-release formulations for fighting infectious diseases

Malaria is a principal cause of illness and death in countries where the disease is endemic. Personal protection against mosquitoes using repellents could be a useful method that can reduce and/or prevent transmission of mosquito-borne diseases. The available repellent products, such as creams, roll-ons, and sprays for personal protection against mosquitoes, lack adequate long-term efficacy. In most cases, they need to be re-applied or replaced frequently. The encapsulation and release of the repellents from several matrices has risen as an alternative process for the development of invention of repellent based systems. The present work reviews various studies about the development and use of repellent controlled-release formulations such as polymer microcapsules, polymer microporous formulations, polymer micelles, nanoemulsions, solid-lipid nanoparticles, liposomes and cyclodextrins as new tools for mosquito-borne malaria control in the outdoor environment. Furthermore, investigation on the mathematical modelling used for the release rate of repellents is discussed in depth by exploring the Higuchi, Korsmeyer-Peppas, Weibull models, as well as the recently developed Mapossa model. Therefore, the studies searched suggest that the final repellents based-product should not only be effective against mosquito vectors of malaria parasites, but also reduce the biting frequency of other mosquitoes transmitting diseases, such as dengue fever, chikungunya, yellow fever and Zika virus. In this way, they will contribute to the improvement in overall public health and social well-being.

Evaluation and Comparison of Solid Lipid Nanoparticles (SLNs) and Nanostructured Lipid Carriers (NLCs) as Vectors to Develop Hydrochlorothiazide Effective and Safe Pediatric Oral Liquid Formulations

The aim of this study was the optimization of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) in terms of physicochemical and biopharmaceutical properties, to develop effective and stable aqueous liquid formulations of hydrochlorothiazide, suitable for paediatric therapy, overcoming its low-solubility and poor-stability problems. Based on solubility studies, Precirol® ATO5 and Transcutol® HP were used as solid and liquid lipids, respectively. The effect of different surfactants, also in different combinations and at different amounts, on particle size, homogeneity and surface-charge of nanoparticles was carefully investigated. The best formulations were selected for drug loading, and evaluated also for entrapment efficiency and release behaviour. For both SLN and NLC series, the use of Gelucire® 44/14 as surfactant rather than PluronicF68 or Tween® 80 yielded a marked particle size reduction (95-75 nm compared to around 600-400 nm), and an improvement in entrapment efficiency and drug release rate. NLC showed a better performance than SLN, reaching about 90% entrapped drug (vs. 80%) and more than 90% drug released after 300 min (vs. about 65%). All selected formulations showed good physical stability during 6-month storage at 4 °C, but a higher loss of encapsulated drug was found for SLNs (15%) than for NLCs (<5%). Moreover, all selected formulations revealed the absence of any cytotoxic effect, as assessed by a cell-viability test on Caco-2 cells and are able to pass the intestinal epithelium as suggested by Caco-2 uptake experiments.

An efficient approach for development and optimisation of curcumin-loaded solid lipid nanoparticles' patch for transdermal delivery

This study aimed to develop and optimise a Curcumin-loaded SLNs (C-SLNs) patch through a new approach for transdermal delivery. C-SLNs were optimised through the response surface central composite design using the modified injection method. Optimised C-SLNs were loaded into a polyvinyl alcohol-based patch through the backing membrane method. Compatibility studies (FTIR, XRPD), in vitro release, ex vivo skin permeation, accelerated stability, and evaluation studies of the patch were also performed. Prepared C-SLNs exhibited average particle diameter of 170 ± 2 nm with an encapsulation efficiency of 90 ± 3.5% (w/w) while SEM illustrated spherical shape of particles. In vitro release data ensured a sustained release for up to 72 hours. The enhancement ratio of C-SLNs based patch with permeation enhancer (PE) was high up to 6.5 folds as compared to patch without PE. It is concluded that the modified injection method is simple, economical, and less time consuming for the development of C-SLNs patch for the transdermal route.

Synthesis of Retinol-Loaded Lipid Nanocarrier via Vacuum Emulsification to Improve Topical Skin Delivery

Retinol has been widely used as an anti-wrinkle active ingredient in cosmetic fields. However, the oxidation of retinol by air was one of the critical problems for application in the skincare field. In this study, Retinol-loaded lipid nanocarriers were prepared via the vacuum emulsification method to increase the stability of retinol vulnerable to air and optimized encapsulation conditions and to increase the penetration efficiency into skin. Optimizing the components of lipid nanocarriers, gradients of carbon chain C8-22 using various lipid species which made the amorphous structure and enough spaces to load retinol inside the capsules were estimated from the lower enthalpy change and peak shift in DSC analysis. The vacuum-assisted lipid nanocarriers (VLN) could help suppress oxidation, which could have advantages to increase the thermal stability of retinol. The retinol-loaded VLN (VLN-ROL) had narrow size distribution under 0.3 PDI value, under 200 nm scaled particle size, and fully negative surface charge of about -50 mV for the electrostatic repulsion to avoid aggregation phenomenon among the lipid nanoparticles. It maintained 90% or more retinol concentration after 4 weeks of storage at 25, 40 and 50 °C and kept stable. The VLN-ROL-containing cream showed improved penetration efficiency applied to porcine skins compared to the commercial retinol 10S from BASF. The total amount of retinol into the skin of VLN-ROL (0.1% of retinol) was enhanced by about 2.2-fold (2.86 ± 0.23 μg) higher than that in 0.1% of bare retinol (about 1.29 ± 0.09 μg). In addition, applied on a 3D Human skin model, the epidermal thickness and the relative percentage of dermal collagen area effectively increased compared to the control and retinol, respectively. Additionally, the level of secreted IL-1α was lower and epidermal damage was weaker than commercial product A. This retinol-loaded lipid nanocarrier could be a potentially superior material for cosmetics and biomedical research.

Expanding Opportunities in Treatment of Leukemia by Solid Lipid Nanoparticles

Background:

Leukemia is a severe type of blood cancer that involves an abnormal proliferation of blood-forming cells. Its conventional treatment faces many challenges, including resistance, lack of specificity and high unwanted toxicity of drugs. Nano drug delivery systems help in overcoming these challenges by delivering the drug to the target site actively or passively. Solid lipid nanoparticles are gaining popularity because they reduce unwanted toxicity, are biocompatible, increase bioavailability and are versatile in terms of incorporated agents (hydrophilic as well as lipophilic drugs, genes, enzymes, etc.).

Purpose:

The aim of this review is to discuss recent advancements in anti-leukemic therapy utilizing solid lipid nanoparticles (SLNs) as successful carriers in enhancing the efficiency of the treatment and bioavailability of the incorporated drug along with overcoming multidrug resistance.

Methods:

This review represents the existing literature on the applications of SLNs in anti-leukemic therapy. A qualitative literature review has been performed for this purpose. We performed keyword research in popular databases such as Google Scholar, Wiley, Elsevier, Scopus, Google patent and PubMed. Only articles published in English and from reputed journals from specific fields were considered. Benchmark studies having major importance from 2000 to 2020 were selected to follow the progress in the field across the globe.

Results:

This article improves the understanding of the role of SLNs in the treatment of leukemia. Traditional anti-leukemic therapy involves many challenges, including resistance, lack of specificity and high unwanted toxicity of drugs. SLNs are emerging as a better alternative to conventional delivery systems as they can reduce unwanted toxicity, are biocompatible, and can provide active as well as passive molecular targeting.

Conclusion:

SLNs provide several advantages in drug delivery for leukemia, including enhancement of efficiency and bioavailability and reduction of toxicity by virtue of their small size, lipid core, non-dependency on organic solvents and versatility in terms of incorporated drugs.

Development of microcapsules using chitosan and alginate via W/O emulsion for the protection of hydrophilic compounds by comparing with hydrogel beads

It is a critical challenge to protect hydrophilic compounds in food or pharmaceutical applications due to their strong tendency to leak out of the capsules into the external aqueous phase. In this work, we developed an encapsulation system that can protect hydrophilic ingredients using polyelectrolyte complexes prepared with chitosan and alginate via water-in-oil (W/O) emulsion. Unlike the traditional preparation of hydrogel beads, in which one material was added dropwise to another that had an opposite charge, we prepared microcapsules by electrostatic interaction between the positively charged -NH₃⁺ groups of chitosan and the negatively charged -COO^- groups of alginate by W/O emulsion via ultrasonication, which prevented the formation of large complexes. The preparation conditions were optimized at an ultrasonic power of 375 W and alginate/chitosan ratio of 7:5, in which the alginate/chitosan microcapsules presented a good polydispersity index of 0.26 and zeta potential of -44.6 mV. The SEM and TEM images showed the microcapsule contained multiple, irregular, conglutinated spheres with a core and shell structure. High encapsulation efficiency and retention efficiency showed its potential to protect hydrophilic components from harsh environments. This method provides a simple route that can efficiently encapsulate a wide range of food or pharmaceutical hydrophilic ingredients.

Rutin-Loaded Solid Lipid Nanoparticles: Characterization and In Vitro Evaluation

This study was aimed at preparing and characterizing solid lipid nanoparticles loading rutin (RT-SLNs) for the treatment of oxidative stress-induced diseases. Phospholipon 80H® as a solid lipid and Polysorbate 80 as surfactant were used for the SLNs preparation, using the solvent emulsification/diffusion method. We obtained spherical RT-SLNs with low sizes, ranging from 40 to 60 nm (hydrodynamic radius) for the SLNs prepared starting from 2% and 5% (w/w) theoretical amount. All prepared formulations showed negative zeta-potential values. RT was efficiently encapsulated within SLNs, obtaining high encapsulation efficiency and drug content percentages, particularly for SLNs prepared with a 5% theoretical amount of RT. In vitro release profiles and analysis of the obtained data applying different kinetic models revealed Fickian diffusion as the main mechanism of RT release from the SLNs. The morphology of RT-SLNs was characterized by scanning electron microscopy (SEM), whereas the interactions between RT and the lipid matrix were investigated by Raman spectroscopy, evidencing spectral modifications of characteristic bands of RT due to the establishment of new interactions. Finally, antioxidant activity assay on human glioblastoma astrocytoma (U373) culture cells showed a dose-dependent activity for RT-SLNs, particularly at the highest assayed dose (50 μM), whereas the free drug showed the lesser activity.

Preparation and Evaluation of Quinapyramine Sulphate-Docusate Sodium Ionic Complex Loaded Lipidic Nanoparticles and Its Scale Up Using Geometric Similarity Principle

The objective of the present work is to prepare and evaluate ionically complexed Quinapyramine sulphate (QS) loaded lipid nanoparticles and its scale up using geometric similarity principle. Docusate sodium (DS), at a molar ratio of 1:2 of QS to DS, was used to prepare hydrophobic Quinapyramine sulphate-Docusate sodium (QS-DS) ionic complex. Based on the difference in total solubility parameter and polarity of QS-DS complex and different lipids, precirol was selected as a lipid for the preparation of lipidic nanoparticles. The particle size, zeta potential, and % entrapment efficiency (%EE) of QS-DS ionic complex loaded solid lipid nanoparticles (QS-DS-SLN) was found to be 250.10 ± 26.04 nm, -27.41 ± 4.18 mV and 81.26 ± 4.67% respectively. FTIR studies confirmed the formation of QS-DS ionic complex. DSC and XRD studies revealed the amorphous nature of QS in QS-DS-SLN. The spherical shape of nanoparticles was confirmed by scanning electron microscopy. QS-DS-SLN showed sustained release of QS for up to 60 h. No significant difference was observed in particle size, zeta potential, and % entrapment efficiency of pilot-scale batch prepared by using rotational speed of 700 rpm. In conclusion, ionic complexation approach can be used to increase % EE of charged drugs into lipid nanoparticles.

Lipid nanoparticles with improved biopharmaceutical attributes for tuberculosis treatment

Tuberculosis is a topic of relevance worldwide because of the social and biological factors that triggered the disease and the economic burden on the health-care systems that imply its therapeutic treatment. Challenges to handle these issues include, among others, research on technological breakthroughs modifying the drug regimens to facilitate therapy adherence, avoid mycobacterium drug resistance, and minimize toxic side-effects. Lipid nanoparticles arise as a promising strategy in this respect as deduced from the reported scientific data. They are prepared from biodegradable and biocompatible starting materials and compared to the use of the free drugs, the entrapment of active molecules into the carriers might lead to both dose reduction and controlled delivery. Moreover, the target to the lung, the organ mainly affected by the disease, could be possible if the particle surface is modified. Although conclusive statements cannot be made considering the limited number of available research works, looking into what has been achieved up to now definitively encourages to continue investigations in this regard.

Development and Optimization of Mirabegron Solid Lipid Nanoparticles as an Oral Drug Delivery for Overactive Bladder

BACKGROUND

Mirabegron (MBN), a β-3 adrenergic agent, is used in the treatment of overactive bladder. MBN has alow water solubility, high first-pass metabolism, and low bioavailability, consequently having poor absorption in the gastrointestinal tract.

OBJECTIVE

The present study is intended to formulate Mirabegron-loaded solid lipid nanoparticles (MBN-SLN) coated with PEG-400 to bypass hepatic first-pass metabolism and to improve its oral bioavailability.

METHODS

MBN-SLNs were developed using glyceryl monostearate by pre-emulsion-ultrasonication method, which was then optimized applying Box-Behnken Design. The optimized batch of MBN-SLN was selected for surface-modification with PEG-400 (MBN-PEG-SLN) and characterized by photon correlation spectroscopy, DSC, and XRD. Bioavailability studies were conducted in Wistar rats after oral administration of plain MBN dispersion, MBN-SLN, and MBN-PEG-SLN.

RESULTS

Stable MBN-SLNs and MBN-PEG-SLN of the optimized batch having a mean particle size of 162.7 nm and 149.9 nm; zeta potential of -39.1 mV and -30.9 mV; % entrapment of 89.90% and 90.12%, respectively, were developed. The results of the in vitro drug release studies demonstrated a significant slow release of MBN from MBN-SLN (69.38%) and MBN-PEG-SLN (61.33%) as compared to the dispersion of pure drug (92.10%). The relative bioavailability, as a result of the in vivo studies, of MBN from MBN-PEG-SLN increased by 2-fold, based on the Cmax values, in comparison with the plain MBN dispersion.

CONCLUSION

Thus, the study established that the oral bioavailability of MBN could be improved by the administration of MBN-PEG-SLN. The obtained results indicate SLNs as a potential drug delivery system for improving the bioavailability of poorly bioavailable drugs such as MBN by abating the first-pass metabolism.

Surface Plasmon Resonance as a Characterization Tool for Lipid Nanoparticles Used in Drug Delivery

The development of drug carriers based in lipid nanoparticles (LNPs) aims toward the synthesis of non-toxic multifunctional nanovehicles that can bypass the immune system and allow specific site targeting, controlled release and complete degradation of the carrier components. Among label free techniques, Surface Plasmon Resonance (SPR) biosensing is a versatile tool to study LNPs in the field of nanotherapeutics research. SPR, widely used for the analysis of molecular interactions, is based on the immobilization of one of the interacting partners to the sensor surface, which can be easily achieved in the case of LNPs by hydrophobic attachment onto commercial lipid- capture sensor chips. In the last years SPR technology has emerged as an interesting strategy for studying molecular aspects of drug delivery that determines the efficacy of the nanotherapeutical such as LNPs' interactions with biological targets, with serum proteins and with tumor extracelullar matrix. Moreover, SPR has contributed to the obtention and characterization of LNPs, gathering information about the interplay between components of the formulations, their response to organic molecules and, more recently, the quantification and molecular characterization of exosomes. By the combination of available sensor platforms, assay quickness and straight forward platform adaptation for new carrier systems, SPR is becoming a high throughput technique for LNPs' characterization and analysis.

Abdulbaqi I, Parumasivam T, Mohtar N, A. Wahab H. Advances in Nanocarriers for Effective Delivery of Docetaxel in the Treatment of Lung Cancer: An Overview

Docetaxel (DCX) is a highly effective chemotherapeutic drug used in the treatment of different types of cancer, including non-small cell lung cancer (NSCLC). The drug is known to have low oral bioavailability due to its low aqueous solubility, poor membrane permeability and susceptibility to hepatic first-pass metabolism. To mitigate these problems, DCX is administered via the intravenous route. Currently, DCX is commercially available as a single vial that contains polysorbate 80 and ethanol to solubilize the poorly soluble drug. However, this formulation causes short- and long-term side effects, including hypersensitivity, febrile neutropenia, fatigue, fluid retention, and peripheral neuropathy. DCX is also a substrate to the drug efflux pump P-glycoprotein (P-gp) that would reduce its concentration within the vicinity of the cells and lead to the development of drug resistance. Hence, the incorporation of DCX into various nanocarrier systems has garnered a significant amount of attention in recent years to overcome these drawbacks. The surfaces of these drug-delivery systems indeed can be functionalized by modification with different ligands for smart targeting towards cancerous cells. This article provides an overview of the latest nanotechnological approaches and the delivery systems that were developed for passive and active delivery of DCX via different routes of administration for the treatment of lung cancer.

Microfluidics-enabled particle engineering of monodisperse solid lipid microparticles with uniform drug loading and diverse solid-state outcomes

Lipids serve as excellent excipients for drug products. Solid lipid microparticles (SLMs) are relatively underexplored in drug delivery; these particles are conventionally prepared using processes yielding polydisperse size distributions, such as spray congealing or emulsification. In this paper, we demonstrate a microfluidics-enabled process for particle engineering of monodisperse solid lipid microparticles with size and content uniformity. To overcome low solubility, we use a volatile solvent to increase drug loading, making the drug-lipid solution a single phase, enabling identical drug loading across particles. We use microfluidic flow extrusion of the solution to generate uniform drug-loaded SLMs, substantially enhancing monodispersity. This method generalises across three drugs-ibuprofen, 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY), and naproxen, and two lipids-beeswax and hard fat (Suppocire NAI 25A), forming particles of various solid states: amorphous naproxen in crystalline lipids, crystalline ROY in crystalline lipids, and a eutectic mixture of ibuprofen-hard fat. In vitro dissolution studies on the ibuprofen-hard fat SLMs reveal gradual release, fitting the Higuchi model with 50-65% drug released over 72 h. This work expands the drug particle engineering toolbox to enable the formulation of SLMs with high precision in particle size and drug loading. Moreover, the diverse solid-state outcomes enabled by our method makes it applicable to various drugs having different formulation requirements (crystalline/amorphous).

Smart nano-micro platforms for ophthalmological applications: The state-of-the-art and future perspectives

Smart nano-micro platforms have been extensively applied for diverse biomedical applications, mostly focusing on cancer therapy. In comparison with conventional nanotechnology, the smart nano-micro matrix can exhibit specific response to exogenous or endogenous triggers, and thus can achieve multiple functions e.g. site-specific drug delivery, bio-imaging and detection of bio-molecules. These intriguing techniques have expanded into ophthalmology in recent years, yet few works have been summarized in this field. In this work, we provide the state-of-the-art of diverse nano-micro platforms based on both the conventional materials (e.g. natural or synthetic polymers, lipid nanomaterials, metal and metal oxide nanoparticles) and emerging nanomaterials (e.g. up-conversion nanoparticles, quantum dots and carbon materials) in ophthalmology, with some smart nano/micro platformers highlighted. The common ocular diseases studied in the field of nano-micro systems are firstly introduced, and their therapeutic method and the related drawback in clinic treatment are presented. The recent progress of different materials for diverse ocular applications is then demonstrated, with the representative nano- and micro-systems highlighted in detail. At last, an in-depth discussion on the clinical translation challenges faced in this field and the future direction are provided. This review would allow the researchers to design more smart nanomedicines in a more rational manner for specific ophthalmology applications.

Solid Lipid Nanoparticles for Topical Drug Delivery: Mechanisms, Dosage Form Perspectives, and Translational Status

Solid lipid nanoparticles (SLNs) have shown potential as a novel lipid-based drug delivery system for the topical applications of innumerable therapeutic compounds. However, the mechanisms governing the absorption and cellular uptake of SLNs through topical route, along with the mechanism of drug release from SLNs are still ambiguous, and require further investigation. In addition, the selection of an appropriate dosage form/formulation base is essential for ease of application of SLNs and to enhance dermal and transdermal delivery. Upscaling and regulatory approvals are other challenges that may impede the clinical translation of SLNs. Therefore, this review focusses on different mechanisms involved in skin penetration and cellular uptake of SLNs. This is followed by a comprehensive discussion on the physicochemical properties of SLNs including various formulation and dosage form factors, which might influence the absorption of SLNs through the skin. Finally, translational status with respect to scale-up and regulatory aspects are also discussed. This review will be useful to researchers with an interest in topical applications of SLNs for the efficient delivery of drugs and cosmetics.

Valsartan solid lipid nanoparticles integrated hydrogel: A challenging repurposed use in the treatment of diabetic foot ulcer, in-vitro/in-vivo experimental study

The article presents an experimental study on the possible repurposed use of valsartan (Val), in the local treatment of uncontrolled diabetic foot ulcer. Solid lipid nanoparticles (SLN), loaded with Val were prepared by applying 3² full factorial design using modified high shear homogenization method. The lipid phase composed of Precirol® ATO 5 (P ATO 5) and/or Gelucire 50/13 (G 50/13) in different ratios and a nonionic emulsifier, Pluronic 188 (P188), was used in different percentages. Optimized formulation was further integrated in hydroxyl propyl methyl cellulose (HPMC) gel for the ease of administration. In-vitro and in-vivo characterizations were investigated. The prepared nanoparticles showed small particle size, high entrapment efficiency and sustained drug release. Microbiologically, Val-SLN showed a prominent decrease in the biofilm mass formation for both gram-positive and gram-negative bacteria, as well as a comparable minimum inhibitory concentration level to levofloxacin alone. Diabetes was induced in 32 neonatal Sprague-Dawley rats. At 8 weeks of age, rats with blood sugar level >160 were subjected to surgically induced ulcer. Treatment with Val-SLN for 12 days revealed enhanced healing characteristics through cyclooxygenase-2 (COX-2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), nitric oxide (NO), transforming growth factor-beta (TGF-β), matrix metalloproteinase (MMPs) and vascular endothelial growth factor (VEGF) pathways. Histological examination revealed re-epithelization in Val-SLN treated ulcer, as well as decrease in collagen using trichrome histomorphometric analysis.

Kinetic Study on Alpha-Form Crystallization of Mixed-Acid Triacylglycerols POP, PPO, and Their Mixture

The crystallization behavior of the metastable α form of triacylglycerols (TAGs) plays a critical role as a precursor for the crystallization of more stable β' and β forms for various applications in food and pharmaceutical products. However, precise analysis of the crystallization kinetics of α has not been performed, likely due to its rapid and complex behavior. This paper presents the observation results of the initial stages of the isothermal crystallization kinetics of α forms of 1,3-dipalmitoyl-2-oleoyl-glycerol (POP), 1,2-dipalmitoyl-3-oleoyl-rac-glycerol (rac-PPO), and molecular compound (MC) crystals of a POP/rac-PPO (1/1) mixture (MCPOP/PPO) using synchrotron radiation time-resolved X-ray diffraction and polarized optical microscopy. In all the TAGs, α crystals with a worm-like morphology started to grow rapidly in the first stage. Then, the α crystals slowly transformed into more stable forms in different manners for different TAG samples. In POP, the conversion was simple, as the α-2 form transformed into γ-3, whereas in rac-PPO, the lamellar distance values of the α-2 form continuously decreased with time and changed into the α-3 form. In the MCPOP/PPO crystals, in contrast, separate crystallization of α-2 of a rac-PPO fraction initially occurred, followed by the crystallization of α-2 of POP, and the two α forms merged into α-2 of MCPOP/PPO. This separate crystallization was caused by large differences in the crystallization kinetics of the α forms of POP and rac-PPO.

Mucoadhesive nanostructured lipid carriers as a cannabidiol nasal delivery system for the treatment of neuropathic pain

The therapeutic potential of cannabidiol (CBD) has been explored to treat several pathologies, including those in which pain is prevalent. However, the oral bioavailability of CBD is low owing to its high lipophilicity and extensive first-pass metabolism. Considering the ability of the nasal route to prevent liver metabolism and increase brain bioavailability, we developed nanostructured lipid carriers (NLCs) for the nasal administration of CBD. We prepared particles with a positively charged surface, employing stearic acid, oleic acid, Span 20^Ⓡ, and cetylpyridinium chloride to obtain mucoadhesive formulations. Characterisation of the CBD-NLC dispersions showed uniform nano-sized particles with diameters smaller than 200 nm, and high drug encapsulation. The mucoadhesion of cationic particles has been related to interactions with negatively charged mucin. Next, we added in-situ gelling polymers to the CBD-NLC dispersion to obtain a CBD-NLC-gel. A thermo-reversible in-situ forming gel was prepared by the addition of Pluronics^Ⓡ. CBD-NLC-gel was characterised by its gelation temperature, rheological behaviour, and mucoadhesion. Both formulations, CBD-NLC and CBD-NLC-gel, showed high mucoadhesion, as assessed by the flow-through method and similar in vitro drug release profiles. The in vivo evaluation showed that CBD-NLC dispersion (without gel), administered intranasally, produced a more significant and lasting antinociceptive effect in animals with neuropathic pain than the oral or nasal administration of CBD solution. However, the nasal administration of CBD-NLC-gel did not lessen mechanical allodynia. These findings demonstrate that in-situ gelling hydrogels are not suitable vehicles for highly lipophilic drugs such as CBD, while cationic CBD-NLC dispersions are promising formulations for the nasal administration of CBD.

Nanostructured lipid carriers as a strategy for encapsulation of active plant constituents: Formulation and in vitro physicochemical characterizations

Active plant constituents obtained from edible sources have manifested their pharmacological potential as a therapy against several diseases. But the lack of their desired physicochemical properties such as solubility, permeability ultimately leads to poor bioavailability. Two potent active plant constituents namely, quercetin and piperine having a problem with either solubility or permeability or both, and hence require an advanced lipid-mediated separate formulation system to improve their aforementioned concerns. Concerning advancement in nanoformulations, lipid-based nano-carriers systems have created their mark as a novel drug delivery system. Therefore, an advanced formulation like nanostructured lipid carriers (NLCs) has been formulated individually for both the active plant constituents/drugs through the solvent evaporation technique using high shear homogenization method followed by sonication. Compritol® 888 ATO, a solid lipid, and squalene as liquid lipid was used in their optimized ratios to formulate individual NLCs. Blank and individual drugs loaded NLCs were further characterized for their in vitro physicochemical properties. NLCs showed a negative surface charge with an average particle size below 200 nm. Electron microscopy images showed an anomalous structure of both the formulated NLCs with higher % drug encapsulation efficiency (DEE) with the desired in vitro drug release profile. In the case of quercetin-NLCs, 93.18 ± 5.5 % DEE was observed followed by drug release up to 45.0 ± 1.3 % within 12 h, while piperine-NLCs showed 91.80 ± 2.51 % DEE and drug release up to 38 ± 5.2 % at the same time. XRD and DSC plots showed the conversion of both the drugs into an amorphous structure encapsulated in a lyophilized NLCs matrix. Finally, the safety profile for formulated NLCs was confirmed by haemolysis assay. Hence, the developed active plant constituents enriched NLCs can further be delivered separately and/or in combination, and also may further be evaluated both in vitro and in vivo means.

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

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

Bringing naturally-occurring saturated fatty acids into biomedical research

This review introduces naturally-occurring saturated fatty acids (NSFAs) and their biomedical applications, including controlled drug release, targeted drug delivery, cancer therapy, antibacterial treatment, and tissue engineering.

Design and Characterization of Elastic Artificial Skin Containing Adenosine-Loaded Solid Lipid Nanoparticles for Treating Wrinkles

Adenosine (AD), which is used for treating wrinkles, exhibits poor skin permeation. The aim of the present study was to develop a cross-linked silicone-based cellulose elastomer as an elastic artificial skin for the treatment of skin wrinkles, a biocompatible lipid-based nano-carrier for enhancing the skin permeation of AD, and a formulation consisting of the lipid-based carrier incorporated in the elastic artificial skin. AD-loaded solid lipid nanoparticles (SLNs) were prepared using a double-emulsion method. Particle characteristics and mechanical properties of SLNs and elastic artificial skin, respectively, were assessed. Skin permeation was evaluated using SkinEthic RHE tissue, a reconstructed human epidermis model. The mean particle size and zeta potential for SLNs ranged from 123.57 to 248.90 nm and -13.23 to -41.23 mV, respectively. The components of neither SLNs nor the elastic artificial skin were cytotoxic, according to cell- and tissue-viability assays and EU classification. SLNs and the elastic artificial skin exhibited sustained drug release for 48 h. The amount of AD released from SLNs and elastic artificial skin was approximately 10 times and 5 times higher, respectively, than that from AD solution. Therefore, elastic artificial skin incorporated with AD-loaded SLNs may serve as a promising topical delivery system for cosmeceutical treatment of skin wrinkles.

Pharmacokinetics and brain distribution studies of perphenazine-loaded solid lipid nanoparticles

BACKGROUND

Perphenazine (PPZ) is a typical antipsychotic that is mainly administrated for the treatment of schizophrenia. Due to its highly lipophilic nature and extensive hepatic first-pass metabolism, its oral bioavailability is low (40%).

OBJECTIVE

The novel nanocarriers like solid lipid nanoparticles (SLN) have been reported to be highly effective for improving the therapeutic effect of drugs. Therefore the main scope of the present investigation was the evaluation of in vivo characteristics of PPZ-SLN in terms of pharmacokinetic parameters and brain distribution.

METHODS

The PPZ-SLN was prepared by the solvent-emulsification and evaporation method. The storage stability of PPZ-SLN and empty SLN powders was studied for 3 months. In vivo pharmacokinetic studies and brain distribution evaluations were performed following a single oral dose administration of PPZ and PPZ-SLN suspensions on male Wistar rats. An HPLC method was established and validated for the quantitative determination of PPZ in plasma and brain samples.

RESULTS

The storage stability studies revealed the good storage stability of the both PPZ-SLN and empty SLN at 4 °C. Compared to PPZ suspension, the relative bioavailability and the brain distribution of PPZ-SLN were increased up to 2-fold and 16-fold, respectively. Mean residence time (MRT) and half-life (t_1/2) of PPZ-SLN were significantly (p value < 0.01) increased in both plasma and brain homogenate compared to PPZ suspension.

CONCLUSION

The significant improvement in the pharmacokinetic properties of PPZ following one oral dose indicates that SLN is a promising drug delivery system for PPZ and shows a high potential for successful brain delivery of this antipsychotic.

Unveiling the Structure and Reactivity of Fatty-Acid Based (Nano)materials Thanks to Efficient and Scalable 17O and 18O-Isotopic Labeling Schemes

Fatty acids are ubiquitous in biological systems and widely used in materials science, including for the formulation of drugs and the surface-functionalization of nanoparticles. However, important questions regarding the structure and reactivity of these molecules are still to be elucidated, including their mode of binding to certain metal cations or materials surfaces. In this context, we have developed novel, efficient, user-friendly, and cost-effective synthetic protocols based on ball-milling, for the 17O and 18O isotopic labeling of two key fatty acids which are widely used in (nano)materials science, namely stearic and oleic acid. Labeled molecules were analyzed by 1H and 13C solution NMR, IR spectroscopy, and mass spectrometry (ESI-TOF and LC-MS), as well as 17O solid state NMR (for the 17O labeled species). In both cases, the labeling procedures were scaled-up to produce up to gram quantities of 17O- or 18O-enriched molecules in just half-a-day, with very good synthetic yields (all ≥84%) and enrichment levels (up to an average of 46% per carboxylic oxygen). The 17O-labeled oleic acid was then used for the synthesis of a metal soap (Zn-oleate) and the surface-functionalization of ZnO nanoparticles (NPs), which were characterized for the first time by high-resolution 17O NMR (at 14.1 and 35.2 T). This allowed very detailed insight into (i) the coordination mode of the oleate ligand in Zn-oleate to be achieved (including information on Zn···O distances) and (ii) the mode of attachment of oleic-acid at the surface of ZnO (including novel information on its photoreactivity upon UV-irradiation). Overall, this work demonstrates the high interest of these fatty acid-enrichment protocols for understanding the structure and reactivity of a variety of functional (nano)materials systems using high resolution analyses like 17O NMR.

Glaucoma: Management and Future Perspectives for Nanotechnology-Based Treatment Modalities

Glaucoma, being asymptomatic for relatively late stage, is recognized as a worldwide cause of irreversible vision loss. The eye is an impervious organ that exhibits natural anatomical and physiological barriers which renders the design of an efficient ocular delivery system a formidable task and challenge scientists to find alternative formulation approaches. In the field of glaucoma treatment, smart delivery systems for targeting have aroused interest in the topical ocular delivery field owing to its potentiality to oppress many treatment challenges associated with many of glaucoma types. The current momentum of nano-pharmaceuticals, in the development of advanced drug delivery systems, hold promises for much improved therapies for glaucoma to reduce its impact on vision loss. In this review, a brief about glaucoma; its etiology, predisposing factors and different treatment modalities has been reviewed. The diverse ocular drug delivery systems currently available or under investigations have been presented. Additionally, future foreseeing of new drug delivery systems that may represent potential means for more efficient glaucoma management are overviewed. Finally, a gab-analysis for the required investigation to pave the road for commercialization of ocular novel-delivery systems based on the nano-technology are discussed.

Nanostructured lipid carrier potentiated oral delivery of raloxifene for breast cancer treatment

Nanotherapeutics in cancer treatment are dominating global science and research, and have been recognized as the pioneering medical care regimen. Raloxifene (RLN) has been used for its anti-proliferative action on mammary tissue, however, it suffers from poor oral bioavailability. This investigation gives an account of the design and development of RLN-loaded nanostructured lipid carriers (RLN-NLCs) using a simple and scalable ultrasonication method for improved oral efficacy and limited offsite toxicity using Compritol^® 888 ATO as a solid lipid and Transcutol^® HP as a liquid lipid. In addition, the optimized RLN-NLCs were in the nanometric range (121 nm) with high % entrapment efficiency (%EE) (81%) for RLN, and were further freeze-dried in the presence of mannitol to enhance the stability of RLN-NLCs in the dry state for long-term use. Morphological observation under a transmission electron microscope and scanning electron microscope revealed the spherical smooth surface nanometric size of RLN-NLCs. Powder x-ray diffraction confirmed the encapsulation of RLN into the RLN-NLC's matrix with reduced crystallinity of the drug. The in vitro release study showed a burst release for an initial 4 h, and sustained release for up to 24 h. Furthermore, the RLN-NLCs showed higher cytotoxicity towards MCF-7 cells in vitro in comparison to RLN suspension, and an ex vivo intestinal permeation study demonstrated improved intestinal permeability of RLN-NLCs. Moreover, the in vivo pharmacokinetic study in female Wistar rats showed a 4.79-fold increment in oral bioavailability of RLN from RLN-NLCs compared to RLN suspension. Taken together, our results pave the way for a new nanotherapeutic approach towards breast cancer treatment.

Ligand-Targeted Delivery of Photosensitizers for Cancer Treatment

Photodynamic therapy (PDT) is a promising cancer treatment which involves a photosensitizer (PS), light at a specific wavelength for PS activation and oxygen, which combine to elicit cell death. While the illumination required to activate a PS imparts a certain amount of selectivity to PDT treatments, poor tumor accumulation and cell internalization are still inherent properties of most intravenously administered PSs. As a result, common consequences of PDT include skin photosensitivity. To overcome the mentioned issues, PSs may be tailored to specifically target overexpressed biomarkers of tumors. This active targeting can be achieved by direct conjugation of the PS to a ligand with enhanced affinity for a target overexpressed on cancer cells and/or other cells of the tumor microenvironment. Alternatively, PSs may be incorporated into ligand-targeted nanocarriers, which may also encompass multi-functionalities, including diagnosis and therapy. In this review, we highlight the major advances in active targeting of PSs, either by means of ligand-derived bioconjugates or by exploiting ligand-targeting nanocarriers.

A Cationic Stearamide-based Solid Lipid Nanoparticle for Delivering Yamanaka Factors: Evaluation of the Transfection Efficiency

Induced pluripotent stem cells (IPSC) are preferred as an alternative source for regenerative medicine, disease modeling, and drug screening due to their unique properties. As seen from the previous studies in the literature, most of the vector systems to transfer reprogramming factors are viral-based and have some well-known limitations. This study aims to develop a non-viral vector system for the transfection of reprogramming factors. Cationic stearamide lipid nanoparticles (CSLN) were prepared via the solvent diffusion method. The obtained CSLNs were used for the delivery of plasmid DNA (pDNA) encoding Oct3/4, Sox2, Klf4, and GFP to fibroblast cell lines. The optimization studies, for zeta potential and particle size of the conjugate, was performed to achieve high cell viability. CSLN63 with 36.5±0.06 mV zeta potential and 173.6±13.91 nm size was used for the transfection of Fibroblast cells. The transfection efficiency was observed by following GFP expression and was found as 70 %±0.11. The expression of the Oct4, Sox2, Klf4 was determined by RT-qPCR; an increase was observed after the 12th cycle in Klf4 (Ct averages: 13,41), Sox2 (Ct averages; 12,4), Oct4 (Ct average; 13,77). The tendency of colonization was observed. The upregulation efficiency of Oct4 and SSEA-1 with CSLN and another non-viral vector designed for the transportation of Yamanaka factors developed in our lab previously were compared with flow cytometer analysis.

Nanotechnology for the Treatment of Allergic Conjunctival Diseases

Allergic conjunctivitis is one of the most common external eye diseases and the prevalence has been increasing. The mainstay of treatment is topical eye drops. However, low bioavailability, low ocular drug penetration, transient resident time on the ocular surface due to tear turnover, frequent topical applications and dependence on patient compliance, are the main drawbacks associated with topical administration. Nanotechnology-based medicine has emerged to circumvent these limitations, by encapsulating the drugs and preventing them from degradation and therefore providing sustained and controlled release. Using a nanotechnology-based approach to load the drug is particularly useful for the delivery of hydrophobic drugs such as immunomodulatory agents, which are commonly used in allergic conjunctival diseases. In this review, different nanotechnology-based drug delivery systems, including nanoemulsions, liposomes, nanomicelles, nanosuspension, polymeric and lipid nanoparticles, and their potential ophthalmic applications, as well as advantages and disadvantages, are discussed. We also summarize the results of present studies on the loading of immunomodulators or nonsteroidal anti-inflammatory drugs to nano-scaled drug delivery systems. For future potential clinical use, research should focus on the optimization of drug delivery designs that provide adequate and effective doses with safe and satisfactory pharmacokinetic and pharmaco-toxic profiles.

Physicochemical Characteristics of Four Limonene-Based Nanoemulsions and Their Larvicidal Properties against Two Mosquito Species, Aedes albopictus and Culex pipiens molestus

Negative impacts on the environment from the continuous use of synthetic insecticides against mosquitoes has driven research towards more ecofriendly products. Phytochemicals, classified as low-risk substances, have been recognized as potential larvicides of mosquitoes; however, problems related to water solubility and stability are limiting factors for their use in mosquito control programs in the field. In this context, many researchers have focused on formulating essential oils in nanoemulsions, exploiting innovative nanotechnology. In the current study, we prepared 4 (R)-(+)-limonene oil-in-water nanoemulsions using low and high energy methods, and we evaluated their physicochemical characteristics (e.g., viscosity, stability, mean droplet diameter, polydispersity index) and their bioactivity against larvae of two mosquito species of great medical importance, namely, Cx. pipiens molestus and Ae. albopictus. According to the dose-response bioassays with the limonene-based nanoemulsions and pure limonene (dissolved in organic solvent), the tested nanoformulations improved the activity of limonene against Ae. albopictus larvae, while the performance of limonene was either the same or better than limonene against Cx. pipiens molestus, depending on the applied system. Overall, we achieved the production of limonene-based delivery nanosystems, with sufficient lethal properties against mosquito larvae to consider them promising larvicidal formulations applicable to mosquito breeding sites.

In vitro synergic activity of diethyldithiocarbamate and 4-nitrochalcone loaded in beeswax nanoparticles against melanoma (B16F10) cells

The use of nanoparticles as drug delivery systems to simultaneously carry several therapeutic agents is an attractive idea to create new synergic treatments and to develop the next generation of cancer therapies. Therefore, the goal of this study was the simultaneous encapsulation of a hydrophilic drug, sodium diethyldithiocarbamate (DETC), and a hydrophobic drug, 4-nitrochalcone (4NC), in beeswax nanoparticles (BNs) to evaluate the in vitro synergic activity of this combination against melanoma (B16F10) cells. BNs were prepared by water/oil/water double emulsion in the absence of organic solvents. Transmission electron microscopy imaging and dynamic light scattering analyses indicated the formation of BNs with a semispherical shape, average diameter below 250 nm, relatively narrow distributions, and negative zeta potential. The double emulsion technique proved to be effective for the simultaneous encapsulation of DETC and 4NC with efficiencies of 86.2% and 98.7%, respectively, and this encapsulation did not affect the physicochemical properties of the BNs. DETC and 4NC loaded in BNs exhibited a higher cytotoxicity toward B16F10 cells than free 4NC and DETC. This simultaneous encapsulation led to a synergic effect of DETC and 4NC on B16F10 cells, decreasing the cell viability from 46% (DETC BNs) and 54% (4NC BNs) to 64% (DETC+4NC BNs). Therefore, the IC₅₀ of DETC+4NC was also lower than that of either when individually encapsulated, and that of free DETC or 4NC. Therefore, DETC and 4NC were efficiently simultaneously encapsulated in BNs and this drug combination was able to generate an in vitro synergic therapeutic effect on B16F10 cells.