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The therapeutic efficacy of camptothecin (CPT), a potent antitumor alkaloid, is hindered by its hydrophobic nature and instability, limiting its clinical use in treating cutaneous squamous cell carcinoma (SCC). This study introduces a novel nano drug delivery system (NDDS) utilizing functionalized mesoporous silica nanoparticles (FMSNs) for efficient CPT delivery. The FMSNs were loaded with CPT and subsequently coated with chitosan (CS) for enhanced stability and bioadhesion. Importantly, CpG oligodeoxynucleotide (CpG ODN) was attached onto the CS-coated FMSNs to leverage the immunostimulatory properties of CpG ODN, augmenting the chemotherapy's efficacy. The final formulation FMSN-CPT-CS-CpG displayed an average size of 241 nm and PDI of 0.316 with an encapsulation efficiency of 95 %. Comprehensive in vitro and in vivo analyses, including B16F10 cells and DMBA/TPA-induced SCC murine model, demonstrated that the FMSN-CPT-CS-CpG formulation significantly enhanced cytotoxicity against B16F10 cells and induced complete regression in 40 % of the in vivo subjects, surpassing the efficacy of standard CPT and FMSN-CPT treatments. This study highlights the potential of combining chemotherapeutic and immunotherapeutic agents in an NDDS for targeted, efficient skin cancer treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

The World Health Organization identifies tuberculosis (TB), caused by Mycobacterium tuberculosis , as a leading infectious killer. Although conventional treatments for TB exist, they come with challenges such as a heavy pill regimen, prolonged treatment duration, and a strict schedule, leading to multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. The rise of MDR strains endangers future TB control. Despite these concerns, the hunt for an efficient treatment continues. One breakthrough has been the use of nanotechnology in medicines, presenting a novel approach for TB treatment. Nanocarriers, such as lipid nanoparticles, nanosuspensions, liposomes, and polymeric micelles, facilitate targeted delivery of anti-TB drugs. The benefits of nanocarriers include reduced drug doses, fewer side effects, improved drug solubility, better bioavailability, and improved patient compliance, speeding up recovery. Additionally, nanocarriers can be made even more targeted by linking them with ligands such as mannose or hyaluronic acid. This review explores these innovative TB treatments, including studies on nanocarriers containing anti-TB drugs and related patents.

Pancreatic cancer represents one of the most lethal cancer types worldwide, with a 5-year survival rate of less than 5%. Due to the inability to diagnose it promptly and the lack of efficacy of existing treatments, research and development of innovative therapies and new diagnostics are crucial to increase the survival rate and decrease mortality. Nanomedicine has been gaining importance as an innovative approach for drug delivery and diagnosis, opening new horizons through the implementation of smart nanocarrier systems, which can deliver drugs to the specific tissue or organ at an optimal concentration, enhancing treatment efficacy and reducing systemic toxicity. Varied materials such as lipids, polymers, and inorganic materials have been used to obtain nanoparticles and develop innovative drug delivery systems for pancreatic cancer treatment. In this review, it is discussed the main scientific advances in pancreatic cancer treatment by nano-based drug delivery systems. The advantages and disadvantages of such delivery systems in pancreatic cancer treatment are also addressed. More importantly, the different types of nanocarriers and therapeutic strategies developed so far are scrutinized.

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

Excessive UV radiation exposure is harmful to skin cells since sunburn is accompanied by oxidative burst, leading to a rapid increase in skin cancer. However, the insufficient UV photoprotection of approved sunscreens and the negative impact of their compositions on ecosystems and human health makes the utility of sunscreen a questionable recommendation. Therefore, discovering UV filters with significant antioxidant activity and improved topical performance and photostability is an urgent need. Recently, the use of nanosized natural molecules incorporated in sunscreens has been a scientific hot topic, as it has been suggested that they provide a synergistic effect with synthetic UV filters, improving overall SPF and antioxidant activity, higher retention on the epidermis, and less toxicity. The aim of this review was to verify the usefulness of sunscreens incorporating flavonoid-loaded nanoparticles. A literature review was performed, where original and review articles published in the last 6 years were analyzed. Formulations containing nanosized flavonoids with improved UVA photoprotection and safer toxicological profiles, associated or not with synthetic filters, are promising sunscreens and more clinical investigation must be performed to validate these findings.

This paper provides a review of the literature on the use of Pluronic® triblock copolymers for drug encapsulation over the last 10 years. A special focus is given to the progress of drug delivery systems (e.g., micelles, liposomes, micro/nanoemulsions, hydrogels and nanogels, and polymersomes and niosomes); the beneficial aspects of Pluronic® triblock copolymers as biological response modifiers and as pharmaceutical additives, adjuvants, and stabilizers, are also discussed. The advantages and limitations encountered in developing site-specific targeting approaches based on Pluronic-based nanostructures in cancer treatment are highlighted, in addition to innovative examples for improving tumor cytotoxicity while reducing side effects., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Introduction: During past years, lipid nanoparticles (LNPs) have emerged as promising carriers for RNA delivery, with several clinical trials focusing on both infectious diseases and cancer. More recently, the success of messenger RNA (mRNA) vaccines for the treatment of severe diseases, such as acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is partially justified by the development of LNPs encapsulating mRNA for efficient cytosolic delivery., Areas Covered: This review examines the production and formulation of LNPs by using microfluidic devices, the status of mRNA-loaded LNPs therapeutics and explores spray drying process, as a promising dehydration process to enhance LNP stability and provide alternative administration routes., Expert Opinion: Microfluidic techniques for preparation of LNPs based on organic solvent injection method promotes the generation of stable, uniform, and monodispersed nanoparticles enabling higher encapsulation efficiency. In particular, the application of microfluidics for the fabrication of mRNA-loaded LNPs is based on rapid mixing of small volumes of ethanol solution containing lipids and aqueous solution containing mRNA. Control of operating parameters and formulation has enabled the optimization of nanoparticle physicochemical characteristics and encapsulation efficiency.

Chitosan is a biodegradable and biocompatible natural polymer that has been extensively explored in recent decades. The Food and Drug Administration has approved chitosan for wound treatment and nutritional use. Furthermore, chitosan has paved the way for advancements in different biomedical applications including as a nanocarrier and tissue-engineering scaffold. Its antibacterial, antioxidant, and haemostatic properties make it an excellent option for wound dressings. Because of its hydrophilic nature, chitosan is an ideal starting material for biocompatible and biodegradable hydrogels. To suit specific application demands, chitosan can be combined with fillers, such as hydroxyapatite, to modify the mechanical characteristics of pH-sensitive hydrogels. Furthermore, the cationic characteristics of chitosan have made it a popular choice for gene delivery and cancer therapy. Thus, the use of chitosan nanoparticles in developing novel drug delivery systems has received special attention. This review aims to provide an overview of chitosan-based nanoparticles, focusing on their versatile properties and different applications in biomedical sciences and engineering., Competing Interests: The authors declare no conflict of interest.

Hymenocardia acida (H. acida) is an African well-known shrub recognized for numerous medicinal properties, including its cancer management potential. The advent of nanotechnology in delivering bioactive medicinal plant extract with poor solubility has improved the drug delivery system, for a better therapeutic value of several drugs from natural origins. This study aimed to evaluate the anticancer properties of H. acida using human lung (H460), breast (MCF-7), and colon (HCT 116) cancer cell lines as well as the production, characterization, and cytotoxicity study of H. acida loaded into PLGA nanoparticles. Benchtop models of Saccharomyces cerevisiae and Raniceps ranninus were used for preliminary toxicity evaluation. Notable cytotoxic activity in benchtop models and human cancer cell lines was observed for H. acida crude extract. The PLGA nanoparticles loading H. acida had a size of about 200 nm and an association efficiency of above 60%, making them suitable to be delivered by different routes. The outcomes from this research showed that H. acida has anticancer activity as claimed from an ethnomedical point of view; however, a loss in activity was noted upon encapsulation, due to the sustained release of the drug.

The emergence of antibiotic-resistant bacteria is a critical worldwide healthcare problem. In the specific case of wound care, new and effective alternatives to currently available solutions are urgently needed. Cellulose-based dressings, for example, could be made more attractive if rendered antimicrobial. This work proposes a new strategy to modify cellulose-based materials with the short antimicrobial hexapeptide MP196 (RWRWRW-NH 2 ) that relies on a biomolecular recognition approach based on carbohydrate binding modules (CBMs). Specifically, we focused on the modification of hydrogels, paper, and microfibrillated cellulose (MFC) with fusions of the CBM3 from Clostridium thermocellum (C. thermocellum) with derivatives of MP196. The fusions are prepared by promoting the formation of a disulfide bond between Cys-terminated derivatives of MP196 and a CBM3 that is pre-anchored in the materials. The CBM3-MP196-modified materials displayed antibacterial activity against Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) that was significantly higher when compared with the activity of materials prepared by physical adsorption of MP196. The biomolecular strategy provides a more favorable orientation, exposure, and distancing of the peptide from the matrix. This versatile concept provides a toolbox for the functionalization of cellulose materials of different origins and architectures with a broad choice in peptides. Functionalization under mild biological conditions avoids further purification steps, allowing for translational research and multiple applications as drug delivery systems, scaffolds for tissue engineering and biomaterials. STATEMENT OF SIGNIFICANCE: The emergence of antibiotic-resistant bacteria is a critical worldwide healthcare problem. In the specific case of wound care, new and effective alternatives to currently available solutions are urgently needed. This work proposes a new strategy to modify cellulose-based materials with a short antimicrobial hexapeptide that relies on a biomolecular recognition approach based on carbohydrate binding modules. The modified materials displayed antibacterial activity against both Gram-negative and Gram-positive bacteria. The biomolecular strategy provides a favorable orientation, exposure, and distancing of the peptide from the matrix. This versatile concept offers a toolbox for the functionalization of different cellulose materials with a broad choice in peptides. Functionalization under mild biological conditions avoids further purification steps, allowing for translational research and multiple applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Ltd.)

Head and neck cancers rank sixth among the most common cancers today, and the survival rate has remained virtually unchanged over the past 25 years, due to late diagnosis and ineffective treatments. They have two main risk factors, tobacco and alcohol, and human papillomavirus infection is a secondary risk factor. These cancers affect areas of the body that are fundamental for the five senses. Therefore, it is necessary to treat them effectively and non-invasively as early as possible, in order to do not compromise vital functions, which is not always possible with conventional treatments (chemotherapy or radiotherapy). In this sense, nanomedicine plays a key role in the treatment and diagnosis of head and neck cancers. Nanomedicine involves using nanocarriers to deliver drugs to sites of action and reducing the necessary doses and possible side effects. The main purpose of this review is to give an overview of the applications of nanocarrier systems to the diagnosis and treatment of head and neck cancer. Herein, several types of delivery strategies, radiation enhancement, inside-out hyperthermia, and theragnostic approaches are addressed.

Cutaneous melanoma is the deadliest type of skin cancer and current treatment is still inadequate, with low patient survival rates. The polyphenol xanthohumol has been shown to inhibit tumourigenesis and metastasization, however its physicochemical properties restrict its application. In this work, we developed PLGA nanoparticles encapsulating xanthohumol and tested its antiproliferative, antitumour, and migration effect on B16F10, malignant cutaneous melanoma, and RAW 264.7, macrophagic, mouse cell lines. PLGA nanoparticles had a size of 312 ± 41 nm and a PdI of 0.259, while achieving a xanthohumol loading of about 90%. The viability study showed similar cytoxicity between the xanthohumol and xanthohumol-loaded PLGA nanoparticles at 48 h with the IC50 established at 10 µM. Similar antimigration effects were observed for free and the encapsulated xanthohumol. It was also observed that the M1 antitumor phenotype was stimulated on macrophages. The ultimate anti-melanoma effect emerges from an association between the viability, migration and macrophagic phenotype modulation. These results display the remarkable antitumour effect of the xanthohumol-loaded PLGA nanoparticles and are the first advance towards the application of a nanoformulation to deliver xanthohumol to reduce adverse effects by currently employed chemotherapeutics.

Knowledge of the beneficial effects of perinatal derivatives (PnD) in wound healing goes back to the early 1900s when the human fetal amniotic membrane served as a biological dressing to treat burns and skin ulcerations. Since the twenty-first century, isolated cells from perinatal tissues and their secretomes have gained increasing scientific interest, as they can be obtained non-invasively, have anti-inflammatory, anti-cancer, and anti-fibrotic characteristics, and are immunologically tolerated in vivo . Many studies that apply PnD in pre-clinical cutaneous wound healing models show large variations in the choice of the animal species (e.g., large animals, rodents), the choice of diabetic or non-diabetic animals, the type of injury (full-thickness wounds, burns, radiation-induced wounds, skin flaps), the source and type of PnD (placenta, umbilical cord, fetal membranes, cells, secretomes, tissue extracts), the method of administration (topical application, intradermal/subcutaneous injection, intravenous or intraperitoneal injection, subcutaneous implantation), and the type of delivery systems (e.g., hydrogels, synthetic or natural biomaterials as carriers for transplanted cells, extracts or secretomes). This review provides a comprehensive and integrative overview of the application of PnD in wound healing to assess its efficacy in preclinical animal models. We highlight the advantages and limitations of the most commonly used animal models and evaluate the impact of the type of PnD, the route of administration, and the dose of cells/secretome application in correlation with the wound healing outcome. This review is a collaborative effort from the COST SPRINT Action (CA17116), which broadly aims at approaching consensus for different aspects of PnD research, such as providing inputs for future standards for the preclinical application of PnD in wound healing., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Pichlsberger, Jerman, Obradović, Tratnjek, Macedo, Mendes, Fonte, Hoegler, Sundl, Fuchs, Schoeberlein, Kreft, Mojsilović and Lang-Olip.)

Wound care has been clinically demanding due to inefficacious treatment that represents an economic burden for healthcare systems. In Europe, approximately 7 million people are diagnosed with untreated wounds, leading to a cost between 6.000€ and 10.000€ per patient/year. In the United States of America, 1.5 million people over 65 years old suffer from chronic wounds. A promising therapeutic strategy is the use of exogenous growth factors because they are decreased at the wound site, limiting the recovery of the skin. Insulin is one of the cheapest growth factors in the market able to accelerate the re-epithelialization and stimulate angiogenesis and cell migration. However, the effectiveness of topical insulin in wound healing is hampered by the proteases in the wound bed. The encapsulation into nanoparticles improves its stability in the wound, providing adhesion to the mucosal surface and allowing its sustained release. The aim of this review is to perform a standing point about a promising strategy to treat different types of wounds by the topical delivery of insulin-loaded nanocarriers.

The Alzheimer's disease is a neurodegenerative condition with severe consequences interfering with patient quality of life. It is characterized as a progressive and irreversible brain disorder hampering memory and thinking, affecting the capacity to perform daily tasks leading to physical and cognitive incapacitation. The conventional treatment occurs by the oral route, but it presents relevant drawbacks such as low bioavailability, fast metabolism, limited brain exposure, and undesirable side effects. The intranasal route has been proposed as a promising alternative to deliver drugs and improve the Alzheimer's disease treatment. Still, there is not a clear alternative delivery system available in the market with advantageous bioavailability and safety. The aim of this review is to perform an overview on the strategies for drug intranasal delivery for Alzheimer's disease treatment. The advantages and disadvantages of this delivery route and the delivery systems developed so far are discussed. A special focus is given on the use of permeation enhancers, the types of intranasal drug delivery devices, as well as possible toxicity concerns.

Poly-ε-caprolactone (PCL) is a biodegradable polyester that has FDA and CE approval as a medical device. Nonetheless, the lack of toxicity exhibited by the polymer cannot be extrapolated to its nanomaterial conformation. Despite PCL-based NPs being widely studied in the biomedical field for their advantages as controlled drug delivery systems, little data describe PCL NPs' toxicity, particularly immunotoxicity. This work assessed different PCL-based delivery systems intended for protein delivery regarding their immunotoxicity and hemocompatibility. Two different molecular weight PCL polymers were used, as well as blends with chitosan and glucan. Results showed that the presence of NaOH during the production of PCL 2 NPs and PCL 2 /glucan NPs induced PCL alkali hydrolysis, generating more reactive groups (carboxyl and hydroxyl) that contributed to an increased toxicity of the NPs (higher reduction in peripheral blood mononuclear cell viability and lower hemocompatibility). PCL 2 /glucan NPs showed an anti-inflammatory activity characterized by the inhibition of LPS stimulated nitric oxide (NO) and TNF-α. In conclusion, generalizations among different PCL NP delivery systems must be avoided, and immunotoxicity assessments should be performed in the early stage of product development to increase the clinical success of the nanomedicine.

Aim: Quinic acid (QA) is a cyclic polyol exhibiting anticancer properties on several cancers. However, potential role of QA derivatives against glioblastoma is not well established. Methodology & results: Sixteen novel QA derivatives and QA- 16 encapsulated poly (lactic-co-glycolic acid) nanoparticles (QA- 16 -NPs) were screened for their anti-glioblastoma effect using standard cell and molecular biology methods. Presence of a tertiary hydroxy and silylether groups in the lead compound were identified for the antitumor activity. QA- 16 have 90% inhibition with the IC 50 of 10.66 μM and 28.22 μM for LN229 and SNB19, respectively. The induction of apoptosis is faster with the increased fold change of caspase 3/7 and reactive oxygen species. Conclusion: QA- 16 and QA- 16 -NPs shows similar cytotoxicity effect, providing the opportunity to use QA- 16 as a potential chemotherapeutic agent.

The delivery of therapeutic proteins remains a challenge, despite recent technological advances. While the delivery of proteins to the lungs is the gold standard for topical and systemic therapy through the lungs, the issue still exists. While pulmonary delivery is highly attractive due to its non-invasive nature, large surface area, possibility of topical and systemic administration, and rapid absorption circumventing the first-pass effect, the absorption of therapeutic proteins is still ineffective, largely due to the immunological and physicochemical barriers of the lungs. Most studies using spray-drying for the nanoencapsulation of drugs focus on the delivery of conventional drugs, which are less susceptible to bioactivity loss, compared to proteins. Herein, the development of polymeric nanoparticles by spray-drying for the delivery of therapeutic proteins is reviewed with an emphasis on its advantages and challenges, and the techniques to evaluate their in vitro and in vivo performance. The protein stability within the carrier and the features of the carrier are properly addressed.

The buccal route is considered patient friendly due to its non-invasive nature and ease of administration. Such delivery route has been used as an alternative for the delivery of drugs that undergo first-pass metabolism or are susceptible to pH and enzymatic degradation, such as occurs in the gastrointestinal tract. However, the drug concentration absorbed in the buccal mucosa is often low to obtain an acceptable therapeutic effect, mainly due to the saliva turnover, tongue and masticatory movements, phonation, enzymatic degradation and lack of epithelium permeation. Therefore, the encapsulation of drugs into nanoparticles is an important strategy to avoid such problems and improve their buccal delivery. Different materials from lipids to natural or synthetic polymers and others have been used to protect and deliver drugs in a sustained, controlled or targeted manner, and enhance their uptake through the buccal mucosa improving their bioavailability and therapeutic outcome. Overall, the main aim of this review is to perform an overview about the nanotechnological approaches developed so far to improve the buccal delivery of drugs. Herein, several types of nanoparticles and delivery strategies are addressed, and a special focus on pipeline products is also given., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The renal cell carcinoma (RCC) is the most common type of kidney cancer. Identifying novel and more effective therapies, while minimizing toxicity, continues to be fundamental in curtailing RCC. Rutin, a bioflavonoid widely found in nature, has shown promising anticancer properties, but with limited applicability due to its poor water solubility and pharmacokinetics. Thus, the potential anticancer effects of rutin toward a human renal cancer cell line (786-O), while considering its safety in Vero kidney cells, was assessed, as well as the applicability of ionic liquids (ILs) to improve drug delivery. Rutin (up to 50 µM) did not show relevant cytotoxic effects in Vero cells. However, in 786-O cells, a significant decrease in cell viability was already observed at 50 µM. Moreover, exposure to rutin caused a significant increase in the sub-G1 population of 786-O cells, reinforcing the possible anticancer activity of this biomolecule. Two choline-amino acid ILs, at non-toxic concentrations, enhanced rutin's solubility/loading while allowing the maintenance of rutin's anticancer effects. Globally, our findings suggest that rutin may have a beneficial impact against RCC and that its combination with ILs ensures that this poorly soluble drug is successfully incorporated into ILs-nanoparticles hybrid systems, allowing controlled drug delivery., Competing Interests: The authors declare no conflict of interest.

Diabetes mellitus greatly affects the quality of life of patients and has a worldwide prevalence. Insulin is the most commonly used drug to treat diabetic patients and is usually administered through the subcutaneous route. However, this route of administration is ineffective due to the low concentration of insulin at the site of action. This route of administration causes discomfort to the patient and increases the risk of infection due to skin barrier disturbance caused by the needle. The oral administration of insulin has been proposed to surpass the disadvantages of subcutaneous administration. In this review, we give an overview of the strategies to deliver insulin by the oral route, from insulin conjugation to encapsulation into nanoparticles. These strategies are still under development to attain efficacy and effectiveness that are expected to be achieved in the near future., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The use of functional excipients such as ionic liquids (ILs) and the encapsulation of drugs into nanocarriers are useful strategies to overcome poor drug solubility. The aim of this work was to evaluate the potential of IL-polymer nanoparticle hybrid systems as tools to deliver poorly soluble drugs. These systems were obtained using a methodology previously developed by our group and improved herein to produce IL-polymer nanoparticle hybrid systems. Two different choline-based ILs and poly (lactic-co-glycolic acid) (PLGA) 50:50 or PLGA 75:25 were used to load rutin into the delivery system. The resulting rutin-loaded IL-polymer nanoparticle hybrid systems presented a diameter of 250-300 nm, with a low polydispersity index and a zeta potential of about -40 mV. The drug association efficiency ranged from 51% to 76%, which represents a good achievement considering the poor solubility of rutin. No significant particle aggregation was obtained upon freeze-drying. The presence of the IL in the nanosystem does not affect its sustained release properties, achieving about 85% of rutin released after 72 h. The cytotoxicity studies showed that the delivery system was not toxic to HaCat cells. Our findings may open a new paradigm on the therapy improvement of diseases treated with poorly soluble drugs.

Quercetin and biapigenin are antioxidant and neuroprotective compounds present in Hypericum perforatum, with potential application in neurodegenerative diseases. Quercetin has shown to have excellent antioxidant activities. Biapigenin possesses a distinctive mechanism of action, preventing the onset of calcium deregulation and mitochondrial dysfunction. The main aim of this study was to establish a new delivery system encapsulating H. perforatum neuroprotective fraction, isolated from it,containing quercetin and biapigenin into poly(Ɛ-caprolactone) (PCL) nanoparticles. It also aimed to study its hepatoprotective potential. Different formulation parameters were optimized, resulting in a stable formulation of polymer:compounds ratio 1:0.1 with a mean particle size of 185nm, zeta potential around -20mV and association efficiency close to 100%. Compounds in vitro release, under physiological conditions, showed an initial burst followed by a sustained release. The antioxidant functional properties of these compounds were not altered by encapsulation. PCL-loaded nanoparticles protected HepG 2 cells from intrinsic compound toxicity at high concentrations. Depending on the incubation regimen, quercetin-biapigenin PCL-loaded nanoparticles or free compounds were more effective in protecting HepG 2 cells against tert-butylhydroperoxide-induced toxicity. This is the first report of the encapsulation of a quercetin-biapigenin mixture in a polymeric matrix, specifically, in PCL, with synergic anti-oxidant and hepatoprotective effects., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Aliphatic polyesters have been widely explored for biomedical applications (e.g., drug delivery systems, biomedical devices, and tissue engineering). Recently, polyesters have been used in nanoparticle formulations for the controlled release of monoclonal antibodies (mAbs) for the enhanced efficacy of antibody-based therapy. Polyester-based nanoparticles for mAb delivery provide decreased antibody dosage, increased antibody stability and protection and longer therapeutic action, ultimately translating to an increased therapeutic index. Additionally, nanoencapsulation holds the potential for the selective cellular recognition and internalization of mAbs, in the disease context when intracellular organelles and molecules (e.g., enzymes, transcription factors and oncogenic proteins) are the preferred target. We present here a detailed method to prepare mAb-loaded polyester-based nanoparticles and the various techniques to characterize the resulting nanoparticles and mAb structure. Finally, we highlight different biological approaches to assess the in vitro bioactivity of the antibody upon nanoparticle release.

Therapeutic proteins are widely used to treat severe conditions, such as oncologic and metabolic diseases, and also for vaccination. They are recognized for its high biopotency, but their hydrophilicity and high molecular weight make its transport through membranes difficult to achieve. They may also suffer in vivo structural instability caused by a proteolytic cleavage, turning them biological inactive. Polyester-based nanoparticles are useful tools to overcome such problems, and deliver therapeutic proteins in a controlled and localized manner, decreasing the number of administrations needed and enhancing the therapeutic outcome. The biodegradable and biocompatible nature of such carriers makes them feasible to be administered by invasive and noninvasive routes. Since nanoparticles are produced in suspension form, they are usually lyophilized to increase its long-term storage stability. Therefore, the aim of this work is to propose an intuitive protocol for production and lyophilization of polyester-based nanoparticles for therapeutic proteins delivery. The characterization techniques to evaluate the nanoparticle and lyophilisate features, as well as the structural stability of the loaded protein are also described. For these purposes, PLGA nanoparticles and human insulin are used as models.

Cancer is a major cause of morbidity and mortality worldwide. Chemotherapeutic agents currently used in cancer treatment are associated with severe side effects and development of resistance. Thus, there is a pressing need for novel and more potent anticancer drugs with high selectivity for tumor cells and reduced toxicity to normal tissue. Natural products remain an important source of bioactive compounds and drug prototypes that can lead to new and more effective antitumor agents. Coniferous plants are rich in abietane diterpenoids with a wide range of biological activities that provide useful templates for synthetic modification. Abietic acid and dehydroabietic acid (DHA), the major diterpenic resin acids from Pinus rosin, and dehydroabietylamine found in commercial disproportionated rosin amine, display antibacterial and antitumor properties. These compounds and their synthetic derivatives have been reported as promising anticancer agents with potent growth inhibitory activity against several types of human cancer cell lines, including breast, ovarian, prostate, colon, liver, lung and cervical carcinoma cells. Their mechanisms of action are diverse and include DNA binding, induction of apoptosis or oncosis, tubulin polymerization inhibition and disruption of intracellular cholesterol transport. This review covers the main aspects of natural rosin abietane diterpenoids (abietic acid, DHA and DHAA) and synthetic derivatives concerning their anti-proliferative, cytotoxic and antitumor activities, mechanisms of action and structure- activity relationships relevant for the development of novel anticancer agents for cancer chemotherapy., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Introduction: Over the past two decades, therapeutic antibodies have demonstrated promising results in the treatment of a wide array of diseases. However, the application of antibody-based therapy implies multiple administrations and a high cost of antibody production, resulting in costly therapy. Another disadvantage inherent to antibody-based therapy is the limited stability of antibodies and the low level of tissue penetration. The use of nanoparticles as delivery systems for antibodies allows for a reduction in antibody dosing and may represent a suitable alternative to increase antibody stability Areas covered: We discuss different nanocarriers intended for the delivery of antibodies as well as the corresponding encapsulation methods. Recent developments in antibody nanoencapsulation, particularly the possible toxicity issues that may arise from entrapment of antibodies into nanocarriers, are also assessed. In addition, this review will discuss the alterations in antibody structure and bioactivity that occur with nanoencapsulation. Expert opinion: Nanocarriers can protect antibodies from degradation, ensuring superior bioavailability. Encapsulation of therapeutic antibodies may offer some advantages, including potential targeting, reduced immunogenicity and controlled release. Furthermore, antibody nanoencapsulation may aid in the incorporation of the antibodies into the cells, if intracellular components (e.g. intracellular enzymes, oncogenic proteins, transcription factors) are to be targeted.

An experimental design was established in order to optimize the mechanical properties of two oral film formulations intended for oral delivery of bioactive compounds. Carboxymethylcellulose (CMC) and gelatin type A (GelTA) were selected as polymeric matrix. Scanning electron microscopy revealed that caffeine crystals were homogeneously dispersed onto oral film matrix. Fourier-transform infrared analysis did not indicate formation of new chemical entities. USP modified dissolution assay revealed that GelTA was more effective in controlling caffeine release since maximum caffeine release (97.4%±0.95) after 20min. On the other hand, CMC is better indicated for immediate release since maximum caffeine release (81.1%±2.14) occurred after 4min. Simulation of gastrointestinal tract with ex vivo permeability assay was in accordance with USP dissolution assay (42.0%±7.79 and 15.3%±4.0 of caffeine released from CMC and GelTA oral films (OF), respectively, permeated porcine intestinal mucosa after 120min). CMCOF and GelTAOF optimized formulations represent two suitable oral delivery systems for immediate and controlled release, respectively., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Monoclonal antibodies have deserved a remarkable interest for more than 40 years as a vital tool for the treatment of various diseases. Still, there is a raising interest to develop advanced monoclonal antibody delivery systems able to tailor pharmacokinetics. Bevacizumab is a humanized immunoglobulin IgG1 used in antiangiogenic therapies due to its capacity to inhibit the interaction between vascular endothelial growth factor and its receptor. However, bevacizumab-based antiangiogenic therapy is not always effective due to poor treatment compliance associated to multiples administrations and drug resistance. In this work, we show a promising strategy of encapsulating bevacizumab to protect and deliver it, in a controlled manner, increasing the time between administrations and formulation shelf-life. Nanoencapsulation of bevacizumab represents a significant advance for selective antiangiogenic therapies since extracellular, cell surface and intracellular targets can be reached. The present study shows that bevacizumab-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles does not impair its native-like structure after encapsulation and fully retain the bioactivity, making this nanosystem a new paradigm for the improvement of angiogenic therapy.

Purpose: The freezing step in lyophilization is the most determinant for the quality of biopharmaceutics. Using insulin as model of therapeutic protein, our aim was to evaluate the freezing effect in the stability and bioactivity of insulin-loaded PLGA nanoparticles. The performance of trehalose, sucrose and sorbitol as cryoprotectants was evaluated., Methods: Cryoprotectants were co-encapsulated with insulin into PLGA nanoparticles and lyophilized using an optimized cycle with freezing at -80°C, in liquid nitrogen, or ramped cooling at -40°C. Upon lyophilization, the stability of protein structure and in vivo bioactivity were assessed., Results: Insulin was co-encapsulated with cryoprotectants resulting in particles of 243-394 nm, zeta potential of -32 to -35 mV, and an association efficiency above 90%. The cryoprotectants were crucial to mitigate the freezing stresses and better stabilize the protein. The insulin structure maintenance was evident and close to 90%. Trehalose co-encapsulated insulin-loaded PLGA nanoparticles demonstrated enhanced hypoglycemic effect, comparatively to nanoparticles without cryoprotectant and added with trehalose, due to a superior insulin stabilization and bioactivity., Conclusions: The freezing process may be detrimental to the structure of protein loaded into nanoparticles, with negative consequences to bioactivity. The co-encapsulation of cryoprotectants mitigated the freezing stresses with benefits to protein bioactivity.

Introduction: Progress in drug delivery and a better quality of life for patients, relies on the development of new and suitable drug carrier systems, with unequivocal therapeutic benefits, low systemic toxicity and reduced side effects. Lipid-polymeric nanoparticles have been explored to produce nanocarriers due to their features and applications such as high drug entrapment, physical-chemical stability and controlled release properties., Areas Covered: In this review, we describe several hybrid nanoparticles obtained from mixing a polymer with a lipid matrix. This association can potentiate the efficacy of drug delivery systems, due to the enhancement of encapsulation efficiency and loading capacity, tailoring the drug release according to the therapeutic purpose, and improving the drug uptake by targeting it to specific receptors. Contrary to lipid nanoparticles, these hybrid nanoparticles can decrease the initial burst release and promote a more sustained and localized release of the drug., Expert Opinion: Lipid-polymeric nanoparticles are versatile vehicles for drug delivery by different administration routes in the treatment of multiple diseases. Different solid lipids, polymers, surfactants and techniques for producing these carriers have been investigated, revealing the importance of their composition to achieve optimal characteristics to drug delivery.

Aim: Explore the use of polymeric micelles in the development of powders intended for pulmonary delivery of biopharmaceuticals, using insulin as a model protein., Materials & Methods: Formulations were assessed in vitro for aerosolization properties and in vivo for efficacy and safety using a streptozotocin-induced diabetic rat model., Results: Powders presented good aerosolization properties like fine particle fraction superior to 40% and a mass median aerodynamic diameter inferior of 6 μm. Endotracheally instilled powders have shown a faster onset of action than subcutaneous administration of insulin at a dose of 10 IU/kg, with pharmacological availabilities up to 32.5% of those achieved by subcutaneous route. Additionally, micelles improved the hypoglycemic effect of insulin. Bronchoalveolar lavage screening for toxicity markers (e.g., lactate dehydrogenase, cytokines) revealed no signs of lung inflammation and cytotoxicity 14 days postadministration., Conclusion: Developed powders showed promising safety and efficacy characteristics for the systemic delivery of insulin by pulmonary administration.

The aim of this work was to use annealing as a tool to optimize the lyophilization cycle by decreasing its duration time, and simultaneously preserve the stability of poly(lactic-co-glycolic acid) nanoparticles and with upmost importance, maintain the structural stability of loaded insulin, used as model therapeutic protein. The contribution of a cryoprotectant in this preservation process was also evaluated. Insulin-loaded nanoparticles co-encapsulated with and without trehalose as cryoprotectant were produced, resulting in a particle size of about 250-300 nm, a PdI around 0.25 and a zeta potential in the range of -20 to -24 mV. The insulin association efficiency was higher than 90%, and the loading capacity was of 11-12%. The use of annealing allowed the decrease of duration time of primary drying in about 38%, representing a global decrease of lyophilization time of around 26%. The residual moisture content of all lyophilizates was around 1%, and the reconstitution of lyophilizates obtained using annealing was even faster than those without annealing. The co-encapsulated trehalose better preserved the nanoparticle size throughout the lyophilization process using annealing, compared to formulation containing no cryoprotectant. Fourier-transform infrared spectroscopy showed that the trehalose-containing nanoparticles presented higher insulin structural maintenance, compared to nanoparticles without cryoprotectant, presenting an insulin structural maintenance of 85.3 ± 0.7% and 86.0 ± 1.0% for annealing and no annealing, respectively. This formulation also presented the closest structural similarity with native insulin. Interestingly, the structural features of insulin loaded into nanoparticles upon lyophilization with and without annealing were practically identical, showing that annealing had no detrimental effect in insulin structure. Circular dichroism and fluorescence spectroscopy confirmed these results. Overall, this work gave rise to the importance of annealing in decreasing the duration time of lyophilization of protein-loaded poly(lactic-co-glycolic acid) nanoparticles, and simultaneously ensuring the stability of the carrier and loaded protein., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Lyophilization has been used to improve the long-term stability of polymeric nanoparticles for drug delivery applications, avoiding their instability in suspension. However, this dehydration process may induce stresses to nanoparticles, mitigated by the use of some excipients such as cryo- and lyoprotectants. Still, the lyophilization of polymeric nanoparticles is frequently based in empirical principles, without considering the physical-chemical properties of formulations and the engineering principles of lyophilization. Therefore, the optimization of formulations and the lyophilization cycle is crucial to obtain a good lyophilizate, and guarantee the preservation of nanoparticle stability. The proper characterization of the lyophilizate and nanoparticles has a great importance in achieving these purposes. This review updates the fundaments involved in the optimization procedures for lyophilization of polymeric nanoparticles, with the aim of obtaining the maximum stability of formulations. Different characterization methods to obtain and guarantee a good lyophilized product are also discussed. A special focus is given to encapsulated therapeutic proteins. Overall, this review is a contribution for the understanding of the parameters involved in the lyophilization of polymeric nanoparticles. This may definitely help future works to obtain lyophilized nanoparticles with good quality and with improved therapeutic benefits., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The purpose of this work was to evaluate the influence of the co-encapsulation of lyoprotectants with insulin into PLGA nanoparticles, on the stability of the protein and nanoparticles upon lyophilization. Different lyoprotectants were used, namely trehalose, glucose, sucrose, fructose and sorbitol at 10% (w/v). Insulin-loaded PLGA nanoparticles with co-encapsulated lyoprotectants achieved a mean particle size of 386-466nm, and a zeta potential ranging between -34 and -38mV, dependent on the lyoprotectant used. Formulations had association efficiencies and loading capacities of 85-91% and 10-12%, respectively. The lyophilization process increased the colloidal stability of nanoparticles, and maintained their spherical shape and smooth surface, particularly in presence of lyoprotectants. XRPD revealed that the lyophilizates of nanoparticles with co-encapsulated lyoprotectants were amorphous, whereas formulations with externally added lyoprotectants, except trehalose, showed crystallinity. FTIR assessment showed that co-encapsulating lyoprotectants better preserved insulin structure upon lyophilization with a spectral area overlap of 82-87%, compared to only 72% in lyoprotectant absence. These results were confirmed by circular dichroism spectroscopy. Surprisingly, the simultaneous co-encapsulation and addition of lyoprotectants was detrimental to protein stabilization. The insulin in vitro release studies demonstrated that formulations with co-encapsulated trehalose, glucose, sucrose, fructose and sorbitol achieved 83%, 69%, 70%, 77% and 74%, respectively after 48h. In contrast, formulations added with those lyoprotectants prior lyophilization showed a lower release rate not higher than 60% after 48h. This work gives rise to a different promising strategy of co-encapsulating lyoprotectants and therapeutic proteins, to better stabilize protein structure upon lyophilization., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Diabetes mellitus is a high prevalence and one of the most severe and lethal diseases in the world. Insulin is commonly used to treat diabetes in order to give patients a better life condition. However, due to bioavailability problems, the most common route of insulin administration is the subcutaneous route, which may present patients compliance problems to treatment. The oral administration is thus considered the most convenient alternative to deliver insulin, but it faces important challenges. The low stability of insulin in the gastrointestinal tract and low intestinal permeation, are problems to overcome. Therefore, the encapsulation of insulin into polymer-based nanoparticles is presented as a good strategy to improve insulin oral bioavailability. In the last years, different strategies and polymers have been used to encapsulate insulin and deliver it orally. Polymers with distinct properties from natural or synthetic sources have been used to achieve this aim, and among them may be found chitosan, dextran, alginate, poly(γ-glutamic acid), hyaluronic acid, poly(lactic acid), poly(lactide-co-glycolic acid), polycaprolactone (PCL), acrylic polymers and polyallylamine. Promising studies have been developed and positive results were obtained, but there is not a polymeric-based nanoparticle system to deliver insulin orally available in the market yet. There is also a lack of long term toxicity studies about the safety of the developed carriers. Thus, the aims of this review are first to provide a deep understanding on the oral delivery of insulin and the possible routes for its uptake, and then to overview the evolution of this field in the last years of research of insulin-loaded polymer-based nanoparticles in the academic and industrial fields. Toxicity concerns of the discussed nanocarriers are also addressed., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Alginate-dextran sulfate-based particles obtained by emulsification/internal gelation technology can be considered suitable carriers for oral insulin delivery. A rational study focused on the emulsification and particle recovery steps was developed in order to reduce particles to the nanosize range while keeping insulin bioactivity. There was a decrease in size when ultrasonication was used during emulsification, which was more pronounced when a cosurfactant was added. Ultrasonication add-on after particle recovery decreased aggregation and led to a narrower nanoscale particle-size distribution. Insulin encapsulation efficiency was 99.3%±0.5%, attributed to the strong pH-stabilizing electrostatic effect between insulin and nanoparticle matrix polymers. Interactions between these polymers and insulin were predicted using molecular modeling studies through quantum mechanics calculations that allowed for prediction of the interaction model. In vitro release studies indicated well-preserved integrity of nanoparticles in simulated gastric fluid. Circular dichroism spectroscopy proved conformational stability of insulin and Fourier transform infrared spectroscopy technique showed rearrangements of insulin structure during processing. Moreover, in vivo biological activity in diabetic rats revealed no statistical difference when compared to nonencapsulated insulin, demonstrating retention of insulin activity. Our results demonstrate that alginate-dextran sulfate-based nanoparticles efficiently stabilize the loaded protein structure, presenting good physical properties for oral delivery of insulin.

Therapeutic proteins and peptides demonstrate unique, peerless, pharmacological characteristics such as high specificity to receptors and superior biological mimicking of physiological mechanisms, resulting in a better therapeutic index compared to conventional chemical-derived drugs. However, proteins also present inherent bioavailability limitations. Thus, this paper proposes several effective tools to improve protein/peptide drugs stability, permeability and pharmacokinetics with special emphasis on oral polymeric films as oral delivery platforms. Indeed, oral films present inherent characteristics that can greatly enhance biological performance of proteins and peptides and patient compliance along with other advantages that are critically discussed in this review. A rational choice of excipients addressed in and manufacture processes are also focused. In addition, possible toxicity issues to be overtaken and critical analysis regarding current market tendencies respecting oral films and protein/peptides along with future prospects are disclosed., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Context: Nanotechnology can be applied to deliver and protect antioxidants in order to control the oxidative stress phenomena in several chronic pathologies. Chitosan (CS) nanoparticles are biodegradable carriers that may protect antioxidants with potent biological activity such as rosmarinic acid (RA) in Salvia officinalis (sage) and Satureja montana (savory) extracts for safe and innovative therapies., Objective: Development and characterization of CS nanoparticles as a stable and protective vehicle to deliver RA for medical applications using natural extracts as sage and savory., Materials and Methods: Antioxidant-CS based nanoparticles were prepared by ionic gelation with sodium tripolyphosphate (TPP), at pH 5.8 with a mass ratio of 7:1 (CS:TPP), with a theoretical antioxidant-CS loading of 40-50%. The nanoparticles were then characterized by different methods such as photon correlation spectroscopy, laser Doppler anemometry, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), high-performance liquid chromatographic (HPLC), association efficiency, and antioxidant activity., Results and Discussion: Individual and small sizing nanoparticles, around 300 nm, were obtained. SEM confirmed smooth and spherical nanoparticles after freeze-drying. No chemical interactions were found between antioxidants and CS, after encapsulation, by DSC and FTIR. The association efficiency was 51.2% for RA (with 40% loading) and 96.1 and 98.2% for sage and savory nanoparticles, respectively (both with 50% loading). Antioxidant activity values were higher than 0.0348 eq [Asc. Ac.] g/L/g extract and 0.4251 µmol/eq Trolox/g extract., Conclusion: The extracts under study are promising vehicles for RA drug delivery in CS nanocarriers.

Nanocomposite powders composed by polymeric micelles as vehicles for delivery proteins were developed in this work, using insulin as model protein. Results showed that size and polydispersity of micelles were dependent on the amphiphilic polymer used, being all lower than 300 nm, while all the formulations displayed spherical shape and surface charge close to neutrality. Percentages of association efficiency and loading capacity up to 94.15 ± 3.92 and 8.56 ± 0.36, respectively, were obtained. X-ray photoelectron spectroscopy (XPS) measurements confirmed that insulin was partially present at the hydrophilic shell of the micelles. Lyophilization did not significantly change the physical characteristics of micelles, further providing easily dispersion when in contact to aqueous medium. The native-like conformation of insulin was maintained at high percentages (around 80%) after lyophilization as indicated by Fourier transform infrared spectroscopy (FTIR) and far-UV circular dichroism (CD). Moreover, Raman spectroscopy did not evidenced significant interactions among the formulation components. The formulations shown to be physically stable upon storage up to 6 months both at room-temperature (20 °C) and fridge (4 °C), with only a slight loss (maximum of 15%) of the secondary structure of the protein. Among the polymers tested, Pluronic(®) F127 produced the carrier formulations more promising for delivery of proteins., (Copyright © 2015. Published by Elsevier B.V.)

Introduction: Recent studies show increased prevalence of Cognitive Dysfunction in patients with Chronic Kidney Disease., Objective: To evaluate this association in users enrolled in the Family Health Unit Ponte., Methods: We studied a sample of 246 elderly. We assessed cognitive function using the Mini Mental State Examination and the Glomerular Filtration Rate using the equation Modification of Diet in Renal Disease. The Glomerular Filtration Rate values obtained (ml/min/1,73 m2) were divided into three categories: < 60.00, 60 to 89.99 and ≥ 90. We collected additional variables from the Medical Support Service and studied the data using bivariate analyzes and logistic regression models., Results: The groups with Glomerular Filtration Rate < 60 and ≥ 90 had a higher prevalence of Cognitive Dysfunction, irrespective of other factors. The odds ratios were, respectively, of 4.534 (95%CI: 1.257 to 16.356) and 3.302 (95% CI: 1.434 to 7.607)., Discussion: According to the literature, we found higher prevalence of Cognitive Dysfunction in the group with Glomerular Filtration Rate < 60. The high prevalence of Cognitive Dysfunction in users with GFR ≥ 90 is described in some studies and may be caused by situations that lead to overestimation of that rate, as the states of cachexia, or situations of glomerular hyperfiltration., Conclusion: The relationship between renal function and the prevalence of Cognitive Dysfunction was not linear, but rather in a parabolic shape. Further studies are needed to explain this relationship and to determine the need for monitoring Cognitive Dysfunction in patients with impaired renal function.

Non-invasive insulin delivery systems have potential to overcome the most pressing problem regarding effective treatment of diabetic patients: therapy compliance. To overcome this disadvantage, non-invasive routes such as oral, buccal, pulmonary, nasal and transdermal have been proposed. These new routes of insulin administration may help to suppress hypoglycemia episodes and aid to control weight gain and post-meal glucose. Despite all efforts the invasive route remains preferential, since studies on insulin administration by non-invasive routes conducted to date have not demonstrated clinical efficacy and safety, including some products introduced in the market. Therefore, the aim of this review is to make an update of the current state of administration of insulin by non-invasive routes as alternatives to the conventional invasive route.

Glucagon like peptide-1 (GLP-1) is an incretin hormone that is in the pipeline for type 2 diabetes mellitus (T2DM) therapy. However, oral administration of GLP-1 is hindered by the harsh conditions of the gastrointestinal tract and poor bioavailability. In this study, three nanosystems composed by three different biomaterials (poly(lactide-co-glycolide) polymer (PLGA), Witepsol E85 lipid (solid lipid nanoparticles, SLN) and porous silicon (PSi) were developed and loaded with GLP-1 to study their permeability in vitro. All the nanoparticles presented a size of approximately 200 nm. The nanoparticles' interaction with the mucus and the intestinal cells were enhanced after coating with chitosan (CS). PSi nanosystems presented the best association efficiency (AE) and loading degree (LD), even though a high AE was also observed for PLGA nanoparticles and SLN. Among all the nanosystems, PLGA and PSi were the only nanoparticles able to sustain the release of GLP-1 in biological fluids when coated with CS. This characteristic was also maintained when the nanosystems were in contact with the intestinal Caco-2 and HT29-MTX cell monolayers. The CS-coated PSi nanoparticles showed the highest GLP-1 permeation across the intestinal in vitro models. In conclusion, PLGA + CS and PSi + CS are promising nanocarriers for the oral delivery of GLP-1., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

This work aimed to evaluate the influence of a freeze-drying process using different cryoprotectants on the structure of insulin loaded into poly(lactic-co-glycolic acid) (PLGA) nanoparticles and to assess the stability of these nanoparticles upon 6 months of storage following ICH guidelines. Insulin-loaded PLGA nanoparticles with a size around 450 nm were dehydrated using a standard freeze-drying cycle, using trehalose, glucose, sucrose, fructose, and sorbitol at 10% (w/v) as cryoprotectants. All formulations, except those nonadded of cryoprotectant and added with trehalose, collapsed after freeze-drying. The addition of cryoprotectants increased the nanoparticles stability upon storage. FTIR results showed that insulin maintained its structure after encapsulation in about 88%, decreasing to 71% after freeze-drying. The addition of cryoprotectants prior to freeze-drying increased insulin structural stability an average of up to 79%. Formulations collapsed after freeze-drying showed better protein stabilization upon storage, in special sorbitol added formulation, preserving 76, 80, and 78% of insulin structure at 4 °C, 25 °C/60% RH, and 40 °C/75% RH, respectively. Principal component analysis also showed that the sorbitol-added formulation showed the most similar insulin structural modifications among the tested storage conditions. These findings suggested that regarding nanoparticles stability, cryoprotectants are versatile to be used in a standard freeze-drying, however they present different performances on the stabilization of the loaded protein. Thus, on the freeze-drying of the nanoparticles field, this work gives rise to the importance of the process of optimization, searching for a balance between a good obtainable cake with an optimal structural stabilization of the loaded protein.

This study aims to monitor the secondary structure behaviour of insulin when it is encapsulated into solid lipid nanoparticles (SLN), under the influence of several critical processing parameters. Insulin was used as a therapeutic protein model. Physicochemical properties of insulin-loaded SLN (Ins-SLN) were assessed, with special focus on the insulin secondary structure after its encapsulation into SLN and after freeze-drying using different cryoprotectants (glucose, fructose and sorbitol). Additionally, a 6-month stability study was performed to evaluate the maintenance of insulin secondary structure over time at different storage conditions (4 °C/60% RH, 25 °C/60% RH, 40 °C/75% RH). Ins-SLN were successfully produced with a mean and narrow particle size around 400 nm, zeta potential around -13 mV, an insulin association efficiency of 84%. Physical-chemical properties of SLN were maintained after freeze-drying. FTIR results showed that encapsulated insulin maintained a native-like structure in a degree of similarity around 92% after production, and 84% after freeze-drying. After 6 months, freeze-dried Ins-SLN without cryoprotectant stored at 40 °C/75% RH presented the same degree of structure preservation and morphology. Results revealed that insulin structure can be significantly protected by SLN matrix itself, without a cryoprotectant agent, even using a non-optimized freeze-drying process, and under the harsher storage conditions. Multivariable experimental settled the process parameters to fit with the desired product quality attributes regarding protein and nanoparticle stability., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Oral delivery of insulin may significantly improve the quality of life of diabetes patients who routinely receive insulin by the subcutaneous route. In fact, compared with this administration route, oral delivery of insulin in diabetes treatment offers many advantages: higher patient compliance, rapid hepatic insulinization, and avoidance of peripheral hyperinsulinemia and other adverse effects such as possible hypoglycemia and weight gain. However, the oral delivery of insulin remains a challenge because its oral absorption is limited. The mainbarriers faced by insulin in the gastrointestinal tract are degradation by proteolytic enzymes and lack of transport across the intestinal epithelium. Several strategies to deliver insulin orally have been proposed, but without much clinical or commercial success. Protein encapsulation into nanoparticles is regarded as a promising alternative to administer insulin orally because they have the ability to promote insulin paracellular or transcellular transport across the intestinal mucosa. In this review, different delivery systems intended to increase the oral bioavailability of insulin will be discussed, with a special focus on nanoparticulate carrier systems, as well as the efforts that pharmaceutical companies are making to bring to the market the first oral delivery system of insulin. The toxicological and safety data of delivery systems, the clinical value and progress of oral insulin delivery, and the future prospects in this research field will be also scrutinized., (© 2013 Diabetes Technology Society.)

Type 2 diabetes mellitus (T2DM) is one of the most prevalent diseases worldwide. Current treatments are often associated with off-target effects and do not significantly impact disease progression. New therapies are therefore urgently needed to overcome this social burden. Glucagon-like peptide-1 (GLP-1), an incretin hormone, has been used to control T2DM symptomatology. However, the administration of peptide or proteins drugs is still a huge challenge in the pharmaceutical field, requiring administration by parenteral routes. This article reviews the main hurdles in oral administration of GLP-1 and focuses on the strategies utilized to overcome them., (© 2012 Diabetes Technology Society.)

PLGA nanoparticles are useful to protect and deliver proteins in a localized or targeted manner, with a long-term systemic delivery pattern intended to last for a period of time, depending on polymer bioerosion and biodegradability. However, the principal concern regarding these carriers is the hydrolytic instability of polymer in aqueous suspension. Freeze-drying is a commonly used method to stabilize nanoparticles, and cryoprotectants may be also used, to even increase its physical stability. The aim of the present work was to analyze the influence of cryoprotectants on nanoparticle stability and porosity after freeze-drying, which may influence protein release and stability. It was verified that freeze-drying significantly increased the number of pores on PLGA-NP surface, being more evident when cryoprotectants are added. The presence of pores is important in a lyophilizate to facilitate its reconstitution in water, although this may have consequences to protein release and stability. The release profile of insulin encapsulated into PLGA-NP showed an initial burst in the first 2 h and a sustained release up to 48 h. After nanoparticles freeze-drying the insulin release increased about 18% in the first 2 h due to the formation of pores, maintaining a sustained release during time. After freeze-drying with cryoprotectants, the amount of insulin released was higher for trehalose and lower for sucrose, glucose, fructose and sorbitol comparatively to freeze-dried PLGA-NP with no cryoprotectant added. Besides the porosity, the ability of cryoprotectants to be adsorbed on the nanoparticles surface may also play an important role on insulin release and stability.

The delivery of therapeutic proteins like insulin, exploiting routes of administration different from the traditional injectable forms, has been investigated extensively, taking advantage of the nanotechnology tools available nowadays in the massive drug delivery system pipeline. In this chapter, we describe in detail the preparation of solid lipid nanoparticles (SLN), further coated with the mucoadhesive polymer chitosan, intended for intestinal absorption of insulin after oral administration. We give special focus on the characterization of the SLN and of the biomacromolecule by itself after encapsulation, because of the intrinsic labile properties of insulin during the manufacturing process. We also describe methods to determine the in vitro intestinal permeability of insulin that solid lipid and chitosan-coated SLN can afford, as well as in vivo models to evaluate the hypoglycemic effect in diabetic animals., (Copyright © 2012 Elsevier Inc. All rights reserved.)