Lipophilic drug derivatives in liposomes

Enhancing the efficacy of letrozole-loaded PEGylated nanoliposomes against breast cancer cells: In vitro study

Considering its overall impact on human health, letrozole (Let) has been described as having significant efficacy that could be improved by developing drug delivery systems. Considering the side effects of Let, this study aims to encapsulate Let in liposomes and PEGylated liposome nanoparticles (Lipo-Let-PEG) and evaluate the cytotoxic effects on the MCF-7 breast cancer cell line. For this purpose, the Lipo-Let-PEG formulation was designed and characterized by SEM, DLS, and FTIR methods, and the drug release from the optimized formulation and the stability of the optimized Lipo-Let-PEG were measured. Furthermore, the cytotoxicity and apoptotic studies were performed using MTT assay and flow cytometric analysis. According to the experimental data, the vesicle size and EE% were 170.05 ± 4.15 nm and 87.21 ± 1.36 %, respectively. The cumulative release from Lipo-Let-PEG at pH 5.4 and 7.4 was also approximately 60 % and 50 %, respectively. MTT results showed that Lip-Let-PEG produced more drug cytotoxicity than Lip-Let against MCF-7 cancer cells and was more compatible with normal cells. The results of apoptosis and cell cycle arrest using flow cytometry show that Lipo-Let-PEG caused the most significant increase in apoptotic rates and cell cycle arrest in cancer cells compared to other treated groups. In conclusion, Lipo-Let-PEG can be used as an anticancer agent by arresting cell cycle progression and inducing apoptosis, which can be applied in future studies to prevent breast cancer development.

Targeting ferroptosis for leukemia therapy: exploring novel strategies from its mechanisms and role in leukemia based on nanotechnology

The latest findings in iron metabolism and the newly uncovered process of ferroptosis have paved the way for new potential strategies in anti-leukemia treatments. In the current project, we reviewed and summarized the current role of nanomedicine in the treatment and diagnosis of leukemia through a comparison made between traditional approaches applied in the treatment and diagnosis of leukemia via the existing investigations about the ferroptosis molecular mechanisms involved in various anti-tumor treatments. The application of nanotechnology and other novel technologies may provide a new direction in ferroptosis-driven leukemia therapies. The article explores the potential of targeting ferroptosis, a new form of regulated cell death, as a new therapeutic strategy for leukemia. It discusses the mechanisms of ferroptosis and its role in leukemia and how nanotechnology can enhance the delivery and efficacy of ferroptosis-inducing agents. The article not only highlights the promise of ferroptosis-targeted therapies and nanotechnology in revolutionizing leukemia treatment, but also calls for further research to overcome challenges and fully realize the clinical potential of this innovative approach. Finally, it discusses the challenges and opportunities in clinical applications of ferroptosis.

A comprehensive review on lipid nanocarrier systems for cancer treatment: fabrication, future prospects and clinical trials

Over the last few decades, cancer has been considered a clinical challenge, being among the leading causes of mortality all over the world. Although many treatment approaches have been developed for cancer, chemotherapy is still the most utilized in the clinical setting. However, the available chemotherapeutics-based treatments have several caveats including their lack of specificity, adverse effects as well as cancer relapse and metastasis which mainly explains the low survival rate of patients. Lipid nanoparticles (LNPs) have been utilized as promising nanocarrier systems for chemotherapeutics to overcome the challenges of the currently applied therapeutic strategies for cancer treatment. Loading chemotherapeutic agent(s) into LNPs improves drug delivery at different aspects including specific targeting of tumours, and enhancing the bioavailability of drugs at the tumour site through selective release of their payload, thus reducing their undesired side effects on healthy cells. This review article delineates an overview of the clinical challenges in many cancer treatments as well as depicts the role of LNPs in achieving optimal therapeutic outcomes. Moreover, the review contains a comprehensive description of the many LNPs categories used as nanocarriers in cancer treatment to date, as well as the potential of LNPs for future applications in other areas of medicine and research.

Nano - Based Therapeutic Strategies in Management of Rheumatoid Arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease, progressively distinctive via cartilage destruction, auto-antibody production, severe joint pain, and synovial inflammation. Nanotechnology represents as one of the utmost promising scientific technologies of the 21st century. It exhibits remarkable potential in the field of medicine, including imaging techniques and diagnostic tools, drug delivery systems and providing advances in treatment of several diseases with nanosized structures (less than 100 nm).

OBJECTIVE

Conventional drugs as a cornerstone of RA management including disease-modifying antirheumatic drugs (DMARDS), Glucocorticosteroids, etc are under clinical practice. Nevertheless, their low solubility profile, poor pharmacokinetics behaviour, and non-targeted distribution not only hamper their effectiveness, but also give rise to severe adverse effects which leads to the need for the emergence of nanoscale drug delivery systems.

METHODS

Several types of nano-diagnostic agents and nanocarriers have been identified; including polymeric nanoparticles (NPs), liposomes, nanogels, metallic NPs, nanofibres, carbon nanotubes, nano fullerene etc. Various patents and clinical trial data have been reported in relevance to RA treatment.

RESULTS

Nanocarriers, unlike standard medications, encapsulate molecules with high drug loading efficacy and avoid drug leakage and burst release before reaching the inflamed sites. Because of its enhanced targeting specificity with the ability to solubilise hydrophobic drugs, it acts as an enhanced drug delivery system.

CONCLUSION

This study explores nanoparticles potential role in RA as a carrier for site-specific delivery and its promising strategies to overcome the drawbacks. Hence, it concludes that nanomedicine is advantageous compared with conventional therapy to enhanced futuristic approach.

Nanoformulations for dermal delivery of imiquimod: The race of "soft" against "hard"

Imiquimod (IMQ) is an immunostimulating agent used in the treatment of basal cell carcinoma and actinic keratosis. Due to its low solubility and poor skin bioavailability, the dermal formulation of IMQ remains challenging. In analogy to tyre compounds used in Formula 1 racing, we compare four types of nanosystems belonging to three groups: (i) "hard" nanoparticles in the form of IMQ nanocrystals, (ii) "intermediate" nanoparticles in the form of liposomes and lipid nanocapsules, and (iii) "soft" nanoparticles in the form of a nanoemulsion based on oleic acid. The nanoemulsion and nanocrystals were able to incorporate the highest amount of IMQ (at least 2 wt%) compared to liposomes (0.03 wt%) and lipid nanocapsules (0.08 wt%). Regarding size, liposomes, and lipid nanocapsules were rather small (around 40 nm) whereas nanocrystals and nanoemulsion were larger (around 200 nm). All developed nanoformulations showed high efficiency to deliver IMQ into the skin tissue without undesirable subsequent permeation through the skin to acceptor. Especially, the 2 wt% IMQ nanoemulsion accumulated 129 μg/g IMQ in the skin, compared to 34 μg/g of a 5 wt% commercial cream. The effects of the respective nanoparticulate systems were discussed with respect to their possible diffusion kinetics (Brownian motion vs. settling) in the aqueous phase.

Lyophilization of Nanoparticles, Does It Really Work? Overview of the Current Status and Challenges

Nanoparticles are being increasingly used as drug delivery systems to enhance the delivery to and uptake by target cells and to reduce off-target toxicity of free drugs. However, although the advantages of nanoparticles as drug carriers are clear, there are still some limitations, especially in maintaining their long-term stability. Lyophilization, also known as freeze-drying, has been heavily investigated as a solution to this problem. This strategy has been shown to be effective in increasing both the long-term stability of nanoparticles and the shelf life of the drug product. However, the process is still in need of improvement in several aspects, such as the process parameters, formulation factors, and characterization techniques. This review summarizes the advantages and limitations of nanoparticles for the treatment of disease, advantages and limitations, and the status of the lyophilization of nanoparticles for therapeutic use and provides insight into both the advantages and the limitations.

Heat-Triggered Release of Dexamethasone from Thermosensitive Liposomes Using Prodrugs or Excipients

Dexamethasone (DXM) is a potent glucocorticoid with an anti-inflammatory and anti-angiogenic activity which is widely clinically used. Systemic side effects limit the long-term use of DXM in patients requiring formulations which deliver and selectively release the drug to the diseased tissues. This in vitro study compares the suitability of DXM and commonly used prodrugs dexamethasone-21-phosphate (DXMP) and dexamethasone-21-palmitate (DP) as well as DXM complexed by 2-hydroxypropyl-γ-cyclodextrin (HP-γ-CD) for the use in thermosensitive liposomes (TSL). DXM showed a poor retention and a low final drug:lipid ratio in a 1,2-dipalmitoyl-sn‑glycero-3-phosphodiglycerol-based TSL (DPPG2-TSL) and a low-temperature sensitive liposome (LTSL). In contrast to DXM, DXMP and DP were stably retained at 37 °C in TSL in serum and could be encapsulated with high drug:lipid ratios in DPPG2-TSL and LTSL. DXMP showed a rapid release at mild hyperthermia (HT) from both TSL in serum, whereas DP remained incorporated in the TSL bilayer. According to release experiments with carboxyfluorescein (CF), HP-γ-CD and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) are suitable vehicles for the loading of DXM into DPPG2-TSL and LTSL. Complexation of DXM with HP-γ-CD increased the aqueous solubility of the drug leading to approx. ten times higher DXM:lipid ratio in DPPG2-TSL and LTSL in comparison to un-complexed DXM. Both DXM and HP-γ-CD showed increased release at HT in comparison to 37 °C in serum. In conclusion, DXMP and DXM complexed by HP-γ-CD represent promising candidates for TSL delivery.

Development and application of nanomaterials, nanotechnology and nanomedicine for treating hematological malignancies

Hematologic malignancies (HMs) pose a serious threat to patients' health and life, and the five-year overall survival of HMs remains low. The lack of understanding of the pathogenesis and the complex clinical symptoms brings immense challenges to the diagnosis and treatment of HMs. Traditional therapeutic strategies for HMs include radiotherapy, chemotherapy, targeted therapy and hematopoietic stem cell transplantation. Although immunotherapy and cell therapy have made considerable progress in the last decade, nearly half of patients still relapse or suffer from drug resistance. Recently, studies have emerged that nanomaterials, nanotechnology and nanomedicine show great promise in cancer therapy by enhancing drug targeting, reducing toxicity and side effects and boosting the immune response to promote durable immunological memory. In this review, we summarized the strategies of recently developed nanomaterials, nanotechnology and nanomedicines against HMs and then proposed emerging strategies for the future designment of nanomedicines to treat HMs based on urgent clinical needs and technological progress.

Advances in lipid-based nanocarriers for breast cancer metastasis treatment

Breast cancer (BC) is the most common cancer affecting women worldwide, with over 2 million women diagnosed every year, and close to 8 million women currently alive following a diagnosis of BC in the last 5-years. The side effects such as chemodrug toxicity to healthy tissues and drug resistance severely affect the quality of life of BC patients. To overcome these limitations, many efforts have been made to develop nanomaterial-based drug delivery systems. Among these nanocarriers, lipid-based delivery platforms represented one of the most successful candidates for cancer therapy, improving the safety profile and therapeutic efficacy of encapsulated drugs. In this review we will mainly discuss and summarize the recent advances in such delivery systems for BC metastasis treatment, with a particular focus on targeting the common metastatic sites in bone, brain and lung. We will also provide our perspectives on lipid-based nanocarrier development for future clinical translation.

Nanomedicine as an Emerging Technology to Foster Application of Essential Oils to Fight Cancer

Natural prodrugs extracted from plants are increasingly used in many sectors, including the pharmaceutical, cosmetic, and food industries. Among these prodrugs, essential oils (EOs) are of particular importance. These biologically active volatile oily liquids are produced by medicinal and aromatic plants and characterized by a distinctive odor. EOs possess high anticancer, antibacterial, antiviral, and antioxidant potential but often are associated with low stability; high volatility; and a high risk of deterioration with exposure to heat, humidity, light, or oxygen. Furthermore, their bioavailability is limited because they are not soluble in water, and enhancements are needed to increase their potential to target specific cells or tissues, as well as for controlled release. Nanomedicine, the application of nanotechnology in medicine, may offer efficient solutions to these problems. The technology is based on creating nanostructures in which the natural prodrug is connected to or encapsulated in nanoparticles or submicron-sized capsules that ensure their solubility in water and their targeting properties, as well as controlled delivery. The potential of EOs as anticancer prodrugs is considerable but not fully exploited. This review focusses on the recent progress towards the practical application of EOs in cancer therapy based on nanotechnology applications.

Liposomal Form of 2,4-Dinitrophenol Lipophilic Derivatives as a Promising Therapeutic Agent for ATP Synthesis Inhibition

Mitochondrial uncoupler 2,4-dinitrophenol (2,4-DNP) is a promising antidiabetic and antiobesity agent. Its clinical use is limited by a narrow dynamic range and accumulation in non-target sensitive organs, which results in whole-body toxicity. A liposomal formulation could enable the mentioned drawbacks to be overcome and simplify the liver-targeted delivery and sustained release of 2,4-DNP. We synthesized 2,4-DNP esters with carboxylic acids of various lipophilic degrees using carboxylic acid chloride and then loaded them into liposomes. We demonstrated the effective increase in the entrapment of 2,4-DNP into liposomes when esters were used. Here, we examined the dependence of the sustained release of 2,4-DNP from liposomes on the lipid composition and LogP_oct of the ester. We posit that the optimal chain length of the ester should be close to the palmitic acid and the lipid membrane should be composed of phospholipids with a certain phase transition point depending on the desired release rate. The increased effect of the ATP synthesis inhibition of the liposomal forms of caproic and palmitic acid esters compared to free molecules in liver hepatocytes was demonstrated. The liposomes’ stability could well be responsible for this result. This work demonstrates promising possibilities for the liver-targeted delivery of the 2,4-DNP esters with carboxylic acids loaded into liposomes for ATP synthesis inhibition.

Preparation, characterization, and evaluation of eosin B-loaded nano-liposomes for growth inhibition of Plasmodium falciparum

Malaria is a deadly disease in humans caused by the Plasmodium parasite. High prevalence of malaria and resistance of malaria parasite to currently proposed drugs have increased the need to introduce and use new and effective antimalarial agents. In this study, eosin B was used as an effective antimalarial agent, the efficacy of which has already been confirmed by in vitro models. Also, for efficacy and safety improvement of eosin B, liposomal nanocarrier was used because of diversity and adaptability in controlled drug delivery and targeting. Eosin B was trapped inside liposomal nanocarriers by thin layer hydration method and its optimization was performed based on size, polydispersity index, and drug entrapment efficiency. Finally, the eosin B-loaded liposomes were tested on Plasmodium falciparum in culture to evaluate its anti-plasmodial effect. According to the results, the formulation with DSPC:cholesterol 8:1 (molar ratio) and drug concentration of 3 mg/ml was selected as the optimal form. The optimal nano-liposomes showed a size of 163.3 nm, a polydispersity index of 0.250, and an encapsulation efficiency of 69.94%. The process of drug release from nanocarriers was also obtained about 63% at the end of 72 h. Stability studies over 2 months at 25 °C and 4 °C on the optimum sample showed that the samples stored in the refrigerator were more stable in terms of size characteristics, polydispersity index, and drug entrapment efficiency. The results indicate a greater effect of liposomal-formulated eosin B on inhibiting parasite growth compared to the free eosin B.

Lipid Nanocarriers for Hyperproliferative Skin Diseases

Simple Summary

Different drugs, including antiproliferative and corticosteroids in general, are recommended for the treatment of hyperproliferative skin diseases (HSD). The effectiveness of many of these drugs is limited due to their low solubility in water and low penetration in the skin. The loading of these drugs in lipid nanocarriers, such as lipid nanoparticles and liposomes, has been considered as a successful solution to improve the drug bioavailability through the skin, to control their release kinetics and thus reduce the risk of potential side effects. In this work, we discuss the use of lipid nanocarriers loading drugs against HSD.

Abstract

Hyperproliferative skin diseases (HSD) are a group of diseases that include cancers, pre-cancerous lesions and diseases of unknown etiology that present different skin manifestations in terms of the degree and distribution of the injuries. Anti-proliferative agents used to treat these diseases are so diverse, including 5-aminolevulinic acid, 5-fluorouracil, imiquimod, methotrexate, paclitaxel, podophyllotoxin, realgar, and corticosteroids in general. These drugs usually have low aqueous solubility, which consequently decreases skin permeation. Thus, their incorporation in lipid nanocarriers has been proposed with the main objective to increase the effectiveness of topical treatment and reduce side effects. This manuscript aims to describe the advantages of using lipid nanoparticles and liposomes that can be used to load diversity of chemically different drugs for the treatment of HSD.

A Systematic Approach for Liposome and Lipodisk Preclinical Formulation Development by Microfluidic Technology

Lipid nanoparticles have transformed the drug delivery field enhancing the therapeutic drug performance of small molecules and biologics with several approved drug products. However, in industry, these more complex drug delivery systems such as liposomes require more material and time to develop. Here, we report a liposome and lipodisk decision tree with model compounds of diverse physicochemical properties to understand how to resourcefully optimize encapsulation efficiency (EE) for these lipid-based drug delivery systems. We have identified trends with physicochemical properties such as Log P, where higher Log P compounds such as curcumin were able to efficiently load into the lipid bilayer resulting in high EE with altering the drug/lipid (D/L) ratio. Moderate Log P compounds such as cyclosporine A and dexamethasone had significantly higher encapsulation in lipodisks, which contain higher amounts of PEG lipid compared to liposomes. The EE of negative Log P compounds, like acyclovir, remained low regardless of altering the D/L ratio and PEG concentrations. In this study, microfluidic techniques were employed to fabricate liposomes and lipodisks formulations allowing for a reproducible strategy for formulation development. Both liposome and lipodisk of curcumin demonstrated enhanced in vivo performance compared with a conventional formulation in the rat pharmacokinetic study. This combination of approaches with multiple model compounds and lipid-based drug delivery systems provides a systematic guidance to effective strategies to generate higher EE with minimal drug waste and expedite the process for preclinical development when applied to industry compounds.

Developing Actively Targeted Nanoparticles to Fight Cancer: Focus on Italian Research

Active targeting is a valuable and promising approach with which to enhance the therapeutic efficacy of nanodelivery systems, and the development of tumor-targeted nanoparticles has therefore attracted much research attention. In this field, the research carried out in Italian Pharmaceutical Technology academic groups has been focused on the development of actively targeted nanosystems using a multidisciplinary approach. To highlight these efforts, this review reports a thorough description of the last 10 years of Italian research results on the development of actively targeted nanoparticles to direct drugs towards different receptors that are overexpressed on cancer cells or in the tumor microenvironment. In particular, the review discusses polymeric nanocarriers, liposomes, lipoplexes, niosomes, solid lipid nanoparticles, squalene nanoassemblies and nanobubbles. For each nanocarrier, the main ligands, conjugation strategies and target receptors are described. The literature indicates that polymeric nanoparticles and liposomes stand out as key tools for improving specific drug delivery to the site of action. In addition, solid lipid nanoparticles, squalene nanoparticles and nanobubbles have also been successfully proposed. Taken together, these strategies all offer many platforms for the design of nanocarriers that are suitable for future clinical translation.

Enhancement of Skin Delivery of Drugs Using Proposome Depends on Drug Lipophilicity

The study aims to investigate the propylene glycol-based liposomes named 'proposomes' in enhancing skin permeation of drugs with different physicochemical properties. Ibuprofen, tofacitinib citrate, rhodamine B, and lidocaine were loaded into proposomes. These drug formulations were analyzed for particle size, zeta potential, polydispersity index, entrapment efficiency, and in vitro skin permeation. The confocal laser scanning microscopy was performed on skin treated with calcein and rhodamine B laden proposomes. The transdermal delivery relative to physicochemical properties of drugs such as logP, melting point, molecular weight, solubility, etc., were analyzed. We tested the safety of the proposomes using reconstructed human skin tissue equivalents, which were fabricated in-house. We also used human cadaver skin samples as a control. The proposomes had an average diameter of 128 to 148 nm. The drug's entrapment efficiencies were in the range of 42.9-52.7%, translating into the significant enhancement of drug permeation through the skin. The enhancement ratio was 1.4 to 4.0, and linearly correlated to logP, molecular weight, and melting point. Confocal imaging also showed higher skin permeation of calcein and rhodamine B in proposome than in solution. The proposome was found safe for skin application. The enhancement of skin delivery of drugs through proposomes was dependent on the lipophilicity of the drug. The entrapment efficiency was positively correlated with logP of the drug, which led to high drug absorption.

Investigating the Application of Liposomes as Drug Delivery Systems for the Diagnosis and Treatment of Cancer

Chemotherapy is the routine treatment for cancer despite the poor efficacy and associated off-target toxicity. Furthermore, therapeutic doses of chemotherapeutic agents are limited due to their lack of tissue specificity. Various developments in nanotechnology have been applied to medicine with the aim of enhancing the drug delivery of chemotherapeutic agents. One of the successful developments includes nanoparticles which are particles that range between 1 and 100 nm that may be utilized as drug delivery systems for the treatment and diagnosis of cancer as they overcome the issues associated with chemotherapy; they are highly efficacious and cause fewer side effects on healthy tissues. Other nanotechnological developments include organic nanocarriers such as liposomes which are a type of nanoparticle, although they can deviate from the standard size range of nanoparticles as they may be several hundred nanometres in size. Liposomes are small artificial spherical vesicles ranging between 30 nm and several micrometres and contain one or more concentric lipid bilayers encapsulating an aqueous core that can entrap both hydrophilic and hydrophobic drugs. Liposomes are biocompatible and low in toxicity and can be utilized to encapsulate and facilitate the intracellular delivery of chemotherapeutic agents as they are biodegradable and have reduced systemic toxicity compared with free drugs. Liposomes may be modified with PEG chains to prolong blood circulation and enable passive targeting. Grafting of targeting ligands on liposomes enables active targeting of anticancer drugs to tumour sites. In this review, we shall explore the properties of liposomes as drug delivery systems for the treatment and diagnosis of cancer. Moreover, we shall discuss the various synthesis and functionalization techniques associated with liposomes including their drug delivery, current clinical applications, and toxicology.

Evaluation of release and pharmacokinetics of hexadecylphosphocholine (miltefosine) in phosphatidyldiglycerol-based thermosensitive liposomes

Hexadecylphosphocholine (HePC, Miltefosine) is a drug from the class of alkylphosphocholines with an antineoplastic and antiprotozoal activity. We previously reported that HePC uptake from thermosensitive liposomes (TSL) containing 1,2-dipalmitoyl-sn-glycero-3-phosphodiglycerol (DPPG₂) into cancer cells is accelerated at mild hyperthermia (HT) resulting in increased cytotoxicity. In this study, we compared HePC release of different TSL formulations in serum. HePC showed rapid but incomplete release below the transition temperature (T_m) of investigated TSL formulations in serum. Short heating (5 min) to 42 °C increased HePC release from DPPG₂-TSL (T_m = 41 °C) by a factor of two in comparison to body temperature (37 °C). Bovine serum albumin (BSA) induced HePC release from DPPG₂-TSL comparable to serum. Furthermore, multilamellar vesicles (MLV) were capable to extract HePC from DPPG₂-TSL in a concentration- and temperature-dependent manner. Repetitive exposure of DPPG₂-TSL to MLV at 37 °C led to a fast initial release of HePC which slowed down after subsequent extraction cycles finally reaching approx. 50% HePC release. A pharmacokinetic study in rats revealed a biphasic pattern with an immediate clearance of approx. 50% HePC whereas the remaining 50% HePC showed a prolonged circulation time. We speculate that HePC located in the external leaflet of DPPG₂-TSL is rapidly released upon contact with suitable biological acceptors. As demonstrated by MLV transfer experiments, asymmetric incorporation of HePC into the internal leaflet of DPPG₂-TSL might improve HePC retention in presence of complex biological media and still give rise to HT-induced HePC release.

Light-Activated Biomedical Applications of Chlorophyll Derivatives

Tetrapyrroles are the basis of essential physiological functions in most living organisms. These compounds represent the basic scaffold of porphyrins, chlorophylls, and bacteriochlorophylls, among others. Chlorophyll derivatives, obtained by the natural or artificial degradation of chlorophylls, present unique properties, holding great potential in the scientific and medical fields. Indeed, they can act as cancer-preventing agents, antimutagens, apoptosis inducers, efficient antioxidants, as well as antimicrobial and immunomodulatory molecules. Moreover, thanks to their peculiar optical properties, they can be exploited as photosensitizers for photodynamic therapy and as vision enhancers. Most of these molecules, however, are highly hydrophobic and poorly soluble in biological fluids, and may display undesired toxicity due to accumulation in healthy tissues. The advent of nanomedicine has prompted the development of nanoparticles acting as carriers for chlorophyll derivatives, facilitating their targeted administration with demonstrated applicability in diagnosis and therapy. In this review, the chemical and physical properties of chlorophyll derivatives that justify their usage in the biomedical field, with particular regard to light-activated dynamics are described. Their role as antioxidants and photoactive agents are discussed, introducing the most recent nanomedical applications and focusing on inorganic and organic nanocarriers exploited in vitro and in vivo.

Liposome technologies towards colorectal cancer therapeutics

Colorectal cancer (CRC) is the third most common cancer and the fourth most common deadly cancer worldwide. After treatment with curative intent recurrence rates vary with staging 0-13% in Stage 1, 11-61% in S2 and 28-73% in Stage 3. The toxicity to healthy tissues from chemotherapy and radiotherapy and drug resistance severely affect the quality of life and cancer specific outcomes of CRC patients. To overcome some of these limitations, many efforts have been made to develop nanomaterial-based drug delivery systems. Among these nanocarriers, liposomes represented one of the most successful candidates in delivering targeted oncological treatment, improving safety profile and therapeutic efficacy of encapsulated drugs. In this review we will discuss liposome design with a particular focus on the targeting feature and triggering functions. We will also summarise the recent advances in liposomal delivery system for CRC treatment in both the preclinical and clinical studies. We will finally provide our perspectives on the liposome technology development for the future clinical translation. STATEMENT OF SIGNIFICANCE: Conventional treatments for colorectal cancer (CRC) severely affect the therapeutic effects for advanced patients. With the development of nanomedicines, liposomal delivery system appears to be one of the most promising nanocarriers for CRC treatment. In last three years several reviews in this area have been published focusing on the preclinical research and drug delivery function, which is a fairly narrow focus in the field of liposome technology for CRC therapy. Our review presented the most recent advances of the liposome technology (both clinical and preclinical applications) for CRC with strong potential for further clinical translation. We believe it will attract lots of attention from various audiences, including researchers, clinicians and the industry.

Freeze-drying of nanoparticles: How to overcome colloidal instability by formulation and process optimization

Lyophilization of nanoparticle (NP) suspensions is a promising technology to improve stability, especially during long-term storage, and offers new routes of administration in solid state. Although considered as a gentle drying process, freeze-drying is also known to cause several stresses leading to physical instability, e.g. aggregation, fusion, or content leakage. NPs are heterogeneous regarding their physico-chemical properties which renders them different in their sensitivity to lyophilization stress and upon storage. But still basic concepts can be deducted. We summarize basic colloidal stabilization mechanisms of NPs in the liquid and the dried state. Furthermore, we give information about stresses occurring during the freezing and the drying step of lyophilization. Subsequently, we review the most commonly investigated NP types including lipophilic, polymeric, or vesicular NPs regarding their particle properties, stabilization mechanisms in the liquid state, and important freeze-drying process, formulation and storage strategies. Finally, practical advice is provided to facilitate purposeful formulation and process development to achieve NP lyophilizates with high colloidal stability.

Sweet pepper and its principle constituent capsiate: functional properties and health benefits

Capsiate is a non-pungent analogue of capsaicin. It belongs to the family of capsinoids which are esters of vanillyl alcohol with fatty acids while capsaicin belongs to the family of capsaicinoids that are amides of vanillylamine with a variety of branched-chain fatty acids. While capsaicin is extensively reported for plethora of pharmacological actions, capsiate remains much less explored. Extracted from various species of Capsicum plant, the molecule has also been chemically synthesized via a number of synthetic and enzymatic routes. Based on its action on transient receptor potential vanilloid subfamily member 1 receptors, recent research has focused on its potential roles in treatment of obesity, metabolic disorders, cancer, cardiovascular disorders and gastro-intestinal disorders. Its toxicity profile has been reported to be much safe. The molecule, however, faces the challenge of low aqueous solubility and stability. It has been commercialized for its use as a weight loss supplement. However, the therapeutic potential of the compound which is much beyond boosting metabolism remains unexplored hitherto. This comprehensive review summarizes the studies demonstrating the therapeutic potential of capsiate in various pathological conditions. Discussed also are potential future directions for formulation strategies to develop efficient, safe and cost-effective dosage forms of capsiate to explore its role in various disease conditions. The databases investigated include Cochrane library, Medline, Embase, Pubmed and in-house databases. The search terms were "capsiate," "capsinoids," "thermogenesis," and their combinations. The articles were screened for relevance by going through their abstract. All the articles pertaining to physicochemical, physiological, pharmacological and therapeutic effects of capsiate have been included in the manuscript.

Reconstituted high density lipoprotein (rHDL), a versatile drug delivery nanoplatform for tumor targeted therapy

rHDL is a synthesized drug delivery nanoplatform exhibiting excellent biocompatibility, which possesses most of the advantages of HDL. rHDL shows almost no toxicity and can be degraded to non-toxic substances in vivo. The severe limitation of the application of various antitumor agents is mainly due to their low bioavailability, high toxicity, poor stability, etc. Favorably, antitumor drug-loaded rHDL nanoparticles (NPs), which are known as an important drug delivery system (DDS), help to change the situation a lot. This DDS shows an outstanding active-targeting ability towards tumor cells and improves the therapeutic effect during antitumor treatment while overcoming the shortcomings mentioned above. In the following text, we will mainly focus on the various applications of rHDL in tumor targeted therapy by describing the properties, preparation, receptor active-targeting ability and antitumor effects of antineoplastic drug-loaded rHDL NPs.

Intranasal drug delivery for treatment of Alzheimer's disease

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.

Alzheimer's Disease Targeted Nano-Based Drug Delivery Systems

Alzheimer's disease (AD) is the most common neurodegenerative disease, and is part of a massive and growing health care burden that is destroying the cognitive function of more than 50 million individuals worldwide. Today, therapeutic options are limited to approaches with mild symptomatic benefits. The failure in developing effective drugs is attributed to, but not limited to the highly heterogeneous nature of AD with multiple underlying hypotheses and multifactorial pathology. In addition, targeted drug delivery to the central nervous system (CNS), for the diagnosis and therapy of neurological diseases like AD, is restricted by the challenges posed by blood-brain interfaces surrounding the CNS, limiting the bioavailability of therapeutics. Research done over the last decade has focused on developing new strategies to overcome these limitations and successfully deliver drugs to the CNS. Nanoparticles, that are capable of encapsulating drugs with sustained drug release profiles and adjustable physiochemical properties, can cross the protective barriers surrounding the CNS. Thus, nanotechnology offers new hope for AD treatment as a strong alternative to conventional drug delivery mechanisms. In this review, the potential application of nanoparticle based approaches in Alzheimer's disease and their implications in therapy is discussed.

Prospects and challenges of extracellular vesicle-based drug delivery system: considering cell source

Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, are nanosized membrane vesicles derived from most cell types. Carrying diverse biomolecules from their parent cells, EVs are important mediators of intercellular communication and thus play significant roles in physiological and pathological processes. Owing to their natural biogenesis process, EVs are generated with high biocompatibility, enhanced stability, and limited immunogenicity, which provide multiple advantages as drug delivery systems (DDSs) over traditional synthetic delivery vehicles. EVs have been reported to be used for the delivery of siRNAs, miRNAs, protein, small molecule drugs, nanoparticles, and CRISPR/Cas9 in the treatment of various diseases. As a natural drug delivery vectors, EVs can penetrate into the tissues and be bioengineered to enhance the targetability. Although EVs' characteristics make them ideal for drug delivery, EV-based drug delivery remains challenging, due to lack of standardized isolation and purification methods, limited drug loading efficiency, and insufficient clinical grade production. In this review, we summarized the current knowledge on the application of EVs as DDS from the perspective of different cell origin and weighted the advantages and bottlenecks of EV-based DDS.

Externally Triggered Novel Rapid-Release Sonosensitive Folate-Modified Liposomes for Gemcitabine: Development and Characteristics

PURPOSE

To develop an externally triggered rapid-release targeted system for treating ovarian cancer, gemcitabine (GMC) was entrapped into sonosensitive (SoS) folate (Fo)-modified liposomes (LPs).

METHODS

GMC-loaded LPs (GMC LPs), GMC-loaded Fo-targeted LPs (GMC-Fo LPs), and GMC-loaded Fo-targeted SoS LPs (GMC-SoS Fo LPs) were prepared utilizing a film-hydration technique and evaluated based on particle size, ζ-potential, and percentage entrapped drug. Cellular uptake of the fluorescent delivery systems in Fo-expressing ovarian cancer cells was quantified using flow cytometry. Finally, tumor-targeting ability, in vivo evaluation, and pharmacokinetic studies were performed.

RESULTS

GMC LPs, GMC-Fo LPs, and GMC-SoS Fo LPs were successfully prepared, with sizes of <120.3±2.4 nm, 39.7 mV ζ-potential, and 86.3%±1.84% entrapped drug. Cellular uptake of GMC-SoS Fo LPs improved 6.51-fold over GMC LPs (under ultrasonic irradiation - p<0.05). However, cellular uptake of GMC-Fo LPs improved just 1.24-fold over GMC LPs (p>0.05). Biodistribution study showed that of GMC concentration in tumors treated with GMC-SoS-Fo LPs (with ultrasound) improved 2.89-fold that of free GMC (p<0.05). In vivo, GMC-SoS Fo LPs showed the highest antiproliferative and antitumor action on ovarian cancer.

CONCLUSION

These findings showed that externally triggered rapid-release SoS Fo-modified LPs are a promising system for delivering rapid-release drugs into tumors.

Building Blocks to Design Liposomal Delivery Systems

The flexibility of liposomal carriers does not just simply rely on their capability to encapsulate various types of therapeutic substances, but also on the large array of components used for designing liposome-based nanoformulations. Each of their components plays a very specific role in the formulation and can be easily replaced whenever a different therapeutic effect is desired. It is tempting to describe this by an analogy to Lego blocks, since a whole set of structures, differing in their features, can be designed using a certain pool of blocks. In this review, we focus on different design strategies, where a broad variety of liposomal components facilitates the attainment of straightforward control over targeting and drug release, which leads to the design of the most promising systems for drug delivery. The key aspects of this block-based architecture became evident after its implementation in our recent works on liposomal carriers of antisense oligonucleotides and statins, which are described in the last chapter of this review.

Lipid-Based Nanosystem As Intelligent Carriers for Versatile Drug Delivery Applications

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The contemporary drug discovery research shows that most of the drug candidates are highly potent, but showing poor aqueous solubility leads a variety of challenges for formulation scientists to develop a suitable formulation to improve the systemic bioavailability of such drugs. Lipid-based nanocarriers act as a major and most projecting approach overcoming the limitations which affect several physiochemical properties of drug such as the solubility, partition coefficient and bioavailability or absorption. This also fulfills a variety of product requirements and helps to overcome several limitations as decided by symptoms of the disease, various routes of administration of drug, price concern, increasing strength of product, noxious or harmful effect of drug, and dose efficacy. The lipidic nanosystem formulates aqueous drug in lipid base and is also a commercially feasible approach for the formulation of different dosage forms meant for topical or transdermal, oral, ocular, pulmonary, and parenteral delivery. This review provides a brief on lipid-based drug delivery nanocarrier and the mechanisms by which lipids and lipidic excipients improve the oral absorption of drugs with poor aqueous solubility and also provide a viewpoint on the promising applications of lipidic nanoparticulate systems.

Antioxidants and Nanotechnology: Promises and Limits of Potentially Disruptive Approaches in the Treatment of Central Nervous System Diseases

Many central nervous system (CNS) diseases are still incurable and only symptomatic treatments are available. Oxidative stress is suggested to be a common hallmark, being able to cause and exacerbate the neuronal cell dysfunctions at the basis of these pathologies, such as mitochondrial impairments, accumulation of misfolded proteins, cell membrane damages, and apoptosis induction. Several antioxidant compounds are tested as potential countermeasures for CNS disorders, but their efficacy is often hindered by the loss of antioxidant properties due to enzymatic degradation, low bioavailability, poor water solubility, and insufficient blood-brain barrier crossing efficiency. To overcome the limitations of antioxidant molecules, exploitation of nanostructures, either for their delivery or with inherent antioxidant properties, is proposed. In this review, after a brief discussion concerning the role of the blood-brain barrier in the CNS and the involvement of oxidative stress in some neurodegenerative diseases, the most interesting research concerning the use of nano-antioxidants is introduced and discussed, focusing on the synthesis procedures, functionalization strategies, in vitro and in vivo tests, and on recent clinical trials.

A novel gemcitabine derivative-loaded liposome with great pancreas-targeting ability

Gemcitabine (Gem) is a standard first-line treatment for pancreatic cancer (PC). However, its chemotherapeutic efficacy is hampered by various limitations such as short half-life, metabolic inactivation, and lack of tumor localizing. We previously synthesized a lipophilic Gem derivative (Gem formyl hexadecyl ester, GemC16) that exhibited improved antitumor activity in vitro. In this study, a target ligand N,N-dimethyl-1,3-propanediamine was conjugated to 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[hydroxyl succinimidyl (polyethylene glycol-2000)] (DSPE-PEG-NHS) to form DSPE-PEG-2N. Then, pancreas-targeting liposomes (2N-LPs) were prepared using the film dispersion-ultrasonic method. GemC16-loaded 2N-LPs displayed near-spherical shapes with an average size distribution of 157.2 nm (polydispersity index (PDI) = 0.201). The encapsulation efficiency of GemC16 was up to 97.3% with a loading capacity of 8.9%. In human PC cell line (BxPC-3) and rat pancreatic acinar cell line (AR42J), cellular uptake of 2N-LPs was significantly enhanced compared with that of unmodified PEG-LPs. 2N-LPs exhibited more potent in vitro cytotoxicity against BxPC-3 and AR42J cell lines than PEG-LPs. After systemic administration in mice, 2N-LPs remarkably increased drug distribution in the pancreas. In an orthotopic tumor mouse model of PC, GemC16-bearing liposomes were more effective in preventing tumor growth than free GemC16. Among these treatments, 2N-LPs showed the best curative effect. Together, 2N-LPs represent a promising nanocarrier to achieve pancreas-targeting drug delivery, and this work would provide new ideas for the chemotherapy of PC.

Formulation and evaluation of thymoquinone niosomes: application of developed and validated RP-HPLC method in delivery system

A rapid, accurate, and sensitive reverse phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the estimation of Thymoquinone (TMQ) in API as well as in noisome. The chromatograms were developed with the mobile phase - water: 2-propanol: methanol (50:45:5 v/v/v) as a solvent system at 254 nm. The method was validated as per ICH guidelines for different parameters and the recovery of TMQ was calculated in developed niosomes. Further, TMQ loaded niosomes (TMQNIOS) were prepared and evaluated for different parameters. The optimized TMQNIOS (F3) was further evaluated for surface morphology, in vitro drug release, permeation study, and confocal laser scanning microscopic (CLSM) study. The method showed linearity range between 6.25 and 100 µg/ml with low detection limit and quantitation limit with a value of 2.08 and 6.25 µg/ml. The developed formulations showed the vesicle size and encapsulation efficiency in the range of 157.32 ± 3.15 to 211.44 ± 5.23 nm and 59.32 ± 4.87 to 83.21 ± 3.55%, respectively. The drug release result showed the significant higher release from TMQNIOS in compared to TMQDIS, and the release kinetics data showed Higuchi's equation with highest regression coefficient values. The permeation study and the confocal laser microscopy study further confirmed the enhancement in permeation of TMQ in the intestinal mucosa.

The Why, Where, Who, How, and What of the vesicular delivery systems

Though vesicular delivery systems have been widely explored and reviewed, no comprehensive review exists that covers their development from the inception of the concept to its culmination in the form of regulated marketed formulations. With the advancement of scientific research in the field of nanomedicine, certain category of vesicular delivery systems have successfully reached the global market. Despite extensive research and highly encouraging results in a plethora of pathological conditions in the preclinical studies, translation of these nanomedicines from laboratory to market has been very limited. Aim of this review is to describe comprehensively the various colloidal delivery systems, focusing mainly on their conventional and advanced methods of preparation, different characterization techniques and main success stories of their journey from bench to bedside of the patient. The review also touches the finer nuances of the use of modern formulation approach of DoE (Design of Experiments) in their formulation and the status of regulatory guidelines for the approval of these nanomedicines.

Nanostructured carriers as innovative tools for cancer diagnosis and therapy

Cancer accounts for millions of deaths every year and, due to the increase and aging of the world population, the number of new diagnosed cases is continuously rising. Although many progresses in early diagnosis and innovative therapeutic protocols have been already set in clinical practice, still a lot of critical aspects need to be addressed in order to efficiently treat cancer and to reduce several drawbacks caused by conventional therapies. Nanomedicine has emerged as a very promising approach to support both early diagnosis and effective therapy of tumors, and a plethora of different inorganic and organic multifunctional nanomaterials have been ad hoc designed to meet the constant demand for new solutions in cancer treatment. Given their unique features and extreme versatility, nanocarriers represent an innovative and easily adaptable tool both for imaging and targeted therapy purposes, in order to improve the specific delivery of drugs administered to cancer patients. The current review reports an in-depth analysis of the most recent research studies aiming at developing both inorganic and organic materials for nanomedical applications in cancer diagnosis and therapy. A detailed overview of different approaches currently undergoing clinical trials or already approved in clinical practice is provided.

Self-emulsifying drug delivery system: Mucus permeation and innovative quantification technologies

Mucus is a dynamic barrier which covers and protects the underlying mucosal epithelial membrane against bacteria and foreign particles. This protection mechanism extends to include therapeutic macromolecules and nanoparticles (NPs) through trapping of these particles. Mucus is not only a physical barrier that limiting particles movements based on their sizes but it selectively binds with particles through both hydrophilic and lipophilic interactions. Therefore, nano-carriers for mucosal delivery should be designed to eliminate entrapment by the mucus barrier. For this reason, different strategies have been approached for both solid nano-carriers and liquid core nano-carriers to synthesise muco-diffusive nano-carrier. Among these nano-strategies, Self-Emulsifying Drug Delivery System (SEDDS) was recognised as very promising nano-carrier for mucus delivery. The system was introduced to enhance the dissolution and bioavailability of orally administered insoluble drugs. SEDDS has shown high stability against intestinal enzymatic activity and more importantly, relatively rapid permeation characteristics across mucus barrier. The high diffusivity of SEDDS has been tested using various in vitro measurement techniques including both bulk and individual measurement of droplets diffusion within mucus. The selection and processing of an optimum in vitro technique is of great importance to avoid misinterpretation of the diffusivity of SEDDS through mucus barrier. In conclusion, SEDDS is a system with high capacity to diffuse through intestinal mucus even though this system has not been studied to the same extent as solid nano-carriers.

Preparation and characterization of multimodal hybrid organic and inorganic nanocrystals of camptothecin and gold

We demonstrate a novel inorganic-organic crystalline nanoconstruct, where gold atoms were imbedded in the crystal lattices as defects of camptothecin nanocrystals, suggesting its potential use as simultaneous agents for cancer therapy and bioimaging. The incorporation of gold, a potential computed tomography (CT) contrast agent, in the nanocrystals of camptothecin was detected by transmission electron microscope (TEM) and further quantified by energy dispersive X-ray spectrometry (EDS) and inductively coupled plasma-optical emission spectrometers (ICP-OES). Due to gold's high attenuation coefficient, only a relatively small amount needs to be present in order to create a good noise-to-contrast ratio in CT imaging. The imbedded gold atoms and clusters are expected to share the same biological fate as the camptothecin nanocrystals, reaching and accumulating in tumor site due to the enhanced permeation and retention (EPR) effect.

Intravenous delivery of a liposomal formulation of voriconazole improves drug pharmacokinetics, tissue distribution, and enhances antifungal activity

Voriconazole (VCZ), a triazole with a large spectrum of action is one of the most recommended antifungal agents as the first line therapy against several clinically important systemic fungal infections, including those by Candida albicans. This antifungal has moderate water solubility and exhibits a nonlinear pharmacokinetic (PK) profile. By entrapping VCZ into liposomes, it is possible to circumvent certain downsides of the currently available product such as a reduction in the rate of its metabolization into an inactive form, avoidance of the toxicity of the sulfobutyl ether-beta-cyclodextrin (SBECD), vehicle used to increase its solubility. PKs and biodistribution of VCZ modified by encapsulation into liposomes resulted in improved antifungal activity, due to increased specificity and tissue penetration. In this work, liposomal VCZ resulted in AUC0-24/MIC ratio of 53.51 ± 11.12, whereas VFEND® resulted in a 2.5-fold lower AUC0-24/MIC ratio (21.51 ± 2.88), indicating favorable antimicrobial systemic activity. VCZ accumulation in the liver and kidneys was significantly higher when the liposomal form was used. Protection of the drug from biological degradation and reduced rate of metabolism leads to a 30% reduction of AUC of the inactive metabolite voriconazole-N-oxide (VNO) when the liposomal drug was administered. Liposomal VCZ presents an alternative therapeutic platform, leading to a safe and effective treatment against systemic fungal infections.

Preparation, characterization, and pharmacokinetics of liposomal docetaxel for oral administration

A docetaxel (DTX) liposomal formulation composed of egg phosphatidylcholine, sodium deoxycholate, and stearylamine was developed. Eudragit (0.5%) was coated to deliver the drug to the region between the distal small intestine and the colon. Lyophilized trehalose and mannitol were used as cryoprotectants because they preserve the particle integrity and good appearance. In vitro release studies showed that the amount of drug released from the coated liposomes was low in solution 1, which simulated the pH condition of the stomach. Especially during the average gastric emptying time, the amount of drug released decreased when Eudragit was added. The plasma DTX concentration was evaluated in pharmacokinetic studies. The plasma drug concentration after intravenous (i.v.) administration decreased rapidly within 120 min. Free DTX formulated using Tween 80 and the lyophilized Eudragit-coated liposomal formulation were compared after oral administration. The oral liposomal formulation had a longer half-life (t_1/2) and three-fold higher oral bioavailability. Thus, lyophilized Eudragit-coated liposomal DTX could be a promising therapy for various solid tumors to improve patient convenience and quality of life.