Liposils: An effective strategy for stabilizing Paclitaxel loaded liposomes by surface coating with silica

Photoactive imaging and therapy for colorectal cancer using a CEA-Affimer conjugated Foslip nanoparticle

Theranostic nanoparticles hold promise for simultaneous imaging and therapy in colorectal cancer. Carcinoembryonic antigen can be used as a target for these nanoparticles because it is overexpressed in most colorectal cancers. Affimer reagents are synthetic proteins capable of binding specific targets, with additional advantages over antibodies for targeting. We fabricated silica nanoparticles using a water-in-oil microemulsion technique, loaded them with the photosensitiser Foslip, and functionalised the surface with anti-CEA Affimers to facilitate fluorescence imaging and photodynamic therapy of colorectal cancer. CEA-specific fluorescence imaging and phototoxicity were quantified in colorectal cancer cell lines and a LS174T murine xenograft colorectal cancer model. Anti-CEA targeted nanoparticles exhibited CEA-specific fluorescence in the LoVo, LS174T and HCT116 cell lines when compared to control particles (p < 0.0001). No toxicity was observed in LS174T cancer mouse xenografts or other organs. Following photo-irradiation, the anti-CEA targeted particles caused significant cell death in LoVo (60%), LS174T (90%) and HCT116 (70%) compared to controls (p < 0.0001). Photodynamic therapy (PDT) at 24 h in vivo showed a 4-fold reduction in tumour volume compared to control mouse xenografts (p < 0.0001). This study demonstrates the efficacy of targeted fluorescence imaging and PDT using Foslip nanoparticles conjugated to anti-CEA Affimer nanoparticles in in vitro and in vivo colorectal cancer models.

Overcoming the Low-Stability Bottleneck in the Clinical Translation of Liposomal Pressurized Metered-Dose Inhalers: A Shell Stabilization Strategy Inspired by Biomineralization

Currently, several types of inhalable liposomes have been developed. Among them, liposomal pressurized metered-dose inhalers (pMDIs) have gained much attention due to their cost-effectiveness, patient compliance, and accurate dosages. However, the clinical application of liposomal pMDIs has been hindered by the low stability, i.e., the tendency of the aggregation of the liposome lipid bilayer in hydrophobic propellant medium and brittleness under high mechanical forces. Biomineralization is an evolutionary mechanism that organisms use to resist harsh external environments in nature, providing mechanical support and protection effects. Inspired by such a concept, this paper proposes a shell stabilization strategy (SSS) to solve the problem of the low stability of liposomal pMDIs. Depending on the shell material used, the SSS can be classified into biomineralization (biomineralized using calcium, silicon, manganese, titanium, gadolinium, etc.) biomineralization-like (composite with protein), and layer-by-layer (LbL) assembly (multiple shells structured with diverse materials). This work evaluated the potential of this strategy by reviewing studies on the formation of shells deposited on liposomes or similar structures. It also covered useful synthesis strategies and active molecules/functional groups for modification. We aimed to put forward new insights to promote the stability of liposomal pMDIs and shed some light on the clinical translation of relevant products.

The crossroad of nanovesicles and oral delivery of insulin

INTRODUCTION

Diabetes mellitus is one of the challenging health problems worldwide. Multiple daily subcutaneous injection of insulin causes poor compliance in patients. Development of efficient oral formulations to improve the quality of life of such patients has been an important goal in pharmaceutical industry. However, due to serious issues such as low bioavailability and instability, it has not been achieved yet.

AREAS COVERED

Due to functional properties of the vesicles and the fact that hepatic-directed vesicles of insulin could reach the clinical phases, we focused on three main vesicular delivery systems for oral delivery of insulin: liposomes, niosomes, and polymersomes. Recent papers were thoroughly discussed to provide a broad overview of such oral delivery systems.

EXPERT OPINION

Although conventional liposomes are unstable in the presence of bile salts, their further modifications such as surface coating could increase their stability in the GI tract. Bilosomes showed good flexibility and stability in GI fluids. Also, niosomes were stable, but they could not induce significant hypoglycemia in animal studies. Although polymersomes were effective, they are expensive and there are some issues about their safety and industrial scale-up. Also, we believe that other modifications such as addition of a targeting agent or surface coating of the vesicles could significantly increase the bioavailability of insulin-loaded vesicles.

Nanoparticle-Based Delivery Systems for Vaccines

Vaccination is still the most cost-effective way to combat infectious illnesses. Conventional vaccinations may have low immunogenicity and, in most situations, only provide partial protection. A new class of nanoparticle-based vaccinations has shown considerable promise in addressing the majority of the shortcomings of traditional and subunit vaccines. This is due to recent breakthroughs in chemical and biological engineering, which allow for the exact regulation of nanoparticle size, shape, functionality, and surface characteristics, resulting in improved antigen presentation and robust immunogenicity. A blend of physicochemical, immunological, and toxicological experiments can be used to accurately characterize nanovaccines. This narrative review will provide an overview of the current scenario of the nanovaccine.

Quality by Design-Driven Zeta Potential Optimisation Study of Liposomes with Charge Imparting Membrane Additives

Liposomal formulations, as versatile nanocarrier systems suitable for targeted delivery, have a highly focused role in the therapy development of unmet clinical needs and diagnostic imaging techniques. Formulating nanomedicine with suitable zeta potential is an essential but challenging task. Formulations with a minimum ±30 mV zeta potential are considered stable. The charge of the phospholipid bilayer can be adjusted with membrane additives. The present Quality by Design-derived study aimed to optimise liposomal formulations prepared via the thin-film hydration technique by applying stearylamine (SA) or dicetyl phosphate (DCP) as charge imparting agents. This 32 fractional factorial design-based study determined phosphatidylcholine, cholesterol, and SA/DCP molar ratios for liposomes with characteristics meeting the formulation requirements. The polynomials describing the effects on the zeta potential were calculated. The optimal molar ratios of the lipids were given as 12.0:5.0:5.0 for the SA-PBS pH 5.6 (optimised sample containing stearylamine) and 8.5:4.5:6.5 for the DCP-PBS pH 5.6 (optimised sample containing dicetyl phosphate) particles hydrated with phosphate-buffered saline pH 5.6. The SA-PBS pH 5.6 liposomes had a vesicle size of 108 ± 15 nm, 0.20 ± 0.04 polydispersity index, and +30.1 ± 1.2 mV zeta potential, while these values were given as 88 ± 14 nm, 0.21 ± 0.02, and -36.7 ± 3.3 mV for the DCP-PBS pH 5.6 vesicles. The prepared liposomes acquired the requirements of the zeta potential for stable formulations.

Mannose-Anchored Nano-Selenium Loaded Nanostructured Lipid Carriers of Etravirine for Delivery to HIV Reservoirs

The present investigation aims to develop and explore mannosylated lipid-based carriers to deliver an anti-HIV drug, Etravirine (TMC) and Selenium nanoparticles (SeNPs), to the HIV reservoirs via the mannose receptor. The successful mannosylation was evaluated by the change in zeta potential and lectin binding assay using fluorescence microscopy. Electron microscopy and scattering studies were employed to study the structure and surface of the nanocarrier system. The presence of selenium at the core-shell of the nanocarrier system was confirmed by X-ray photoelectron spectroscopy and energy dispersive X-ray analysis. Further, the in vitro anti-HIV1 efficacy was assessed using HIV1 infected TZM-bl cells followed by in vivo biodistribution studies to evaluate distribution to various reservoirs of HIV. The results exhibited higher effectiveness and a significant increase in the therapeutic index as against the plain drug. The confocal microscopy and flow cytometry studies exhibited the efficient uptake of the coumarin-6 tagged respective formulations. The protective effect of nano selenium toward oxidative stress was evaluated in rats, demonstrating the potential of the lipidic nanoparticle-containing selenium in mitigating oxidative stress in all the major organs. The in vivo biodistribution assessment in rats showed a 12.44, 8.05 and 9.83-fold improvement in the brain, ovary, and lymph node biodistribution, respectively as compared with plain TMC. Delivery of such a combination via mannosylated nanostructured lipid carriers could be an efficient approach for delivering drugs to reservoirs of HIV while simultaneously reducing the oxidative stress induced by such long-term therapies by co-loading Nano-Selenium.

Superiority of Microemulsion-based Hydrogel for Non-Steroidal Anti-Inflammatory Drug Transdermal Delivery: A Comparative Safety and Anti-nociceptive Efficacy Study

Non-steroidal anti-inflammatory drugs (NSAIDs) represent the foundation of pain management caused by inflammatory disorders. Nevertheless, their oral administration induces several side effects exemplified by gastric ulceration, thus, delivering NSAIDs via the skin has become an attractive alternative. Herein, microemulsion-based hydrogel (MBH), proliposomal, and cubosomal gels were fabricated, loaded with diclofenac, and physicochemically characterized. The sizes, charges, surface morphologies, and the state of diclofenac within the reconstituted gels were also addressed. The release pattern and ex-vivo permeation studies using Franz cells were performed via the rat abdominal skin. The formulations were assessed in-vivo on mice skin for their irritation effect and their anti-nociceptive efficacy through the tail-flick test. Biosafety study of the optimal gel was also pointed out. The gels and their dispersion forms displayed accepted physicochemical properties. Diclofenac released in a prolonged manner from the prepared gels. MBH revealed a significantly higher skin permeation and the foremost results regarding in-vivo assessment where no skin irritation or altered histopathological features were observed. MBH further induced a significant anti-nociceptive effect during the tail-flick test with a lower tendency to evoke systemic toxicity. Therefore, limonene-containing microemulsion hydrogel is a promising lipid-based vehicle to treat pain with superior safety and therapeutic efficacy.

Mineral medicine: from traditional drugs to multifunctional delivery systems

Mineral drugs are an important constituent of traditional Chinese medicine (TCM). Taking minerals that contain heavy metals as drugs is a very national characteristic part of TCM. However, the safety and scientific nature of mineral drugs are controversial owing to their heavy metals and strong toxicity. In 2000, the Food and Drug Administration (FDA) authorized arsenic trioxide (ATO) as first-line therapy for acute promyelocytic leukemia. This makes the development and utilization of mineral drugs become a research hotspot. The development of nanomedicine has found a great prospect of mineral drugs in nano-delivery carriers. And that will hold promise to address the numerous biological barriers facing mineral drug formulations. However, the studies on mineral drugs in the delivery system are few at present. There is also a lack of a detailed description of mineral drug delivery systems. In this review, the advanced strategies of mineral drug delivery systems in tumor therapy are summarized. In addition, the therapeutic advantages and research progress of novel mineral drug delivery systems are also discussed. Here, we hope that this will provide a useful reference for the design and application of new mineral drug delivery systems.

Gelatin Coating for the Improvement of Stability and Cell Uptake of Hydrophobic Drug-Containing Liposomes

PURPOSE

Most therapeutic agents have limitations owing to low selectivity and poor solubility, resulting in post-treatment side effects. Therefore, there is a need to improve solubility and develop new formulations to deliver therapeutic agents specifically to the target site. Gelatin is a natural protein that is composed of several amino acids. Previous studies revealed that gelatin contains arginyl-glycyl-aspartic acid (RGD) sequences that become ligands for the integrin receptors expressed on cancer cells. Thus, in this study, we aimed to increase the efficiency of drug delivery into cancer cells by coating drug-encapsulating liposomes with gelatin (gelatin-coated liposomes, GCLs).

METHODS

Liposomes were coated with gelatin using electrostatic interaction and covalent bonding. GCLs were compared with PEGylated liposomes in terms of their size, zeta potential, encapsulation efficiency, stability, dissolution profile, and cell uptake. Results: Small-sized and physically stable GCLs were prepared, and they showed high drug-encapsulation efficiency. An in vitro dissolution study showed sustained release depending on the degree of gelatin coating. Cell uptake studies showed that GCLs were superior to PEGylated liposomes in terms of cancer cell-targeting ability.

CONCLUSIONS

GCLs can be a novel and promising carrier system for targeted anticancer agent delivery. GCLs, which exhibited various characteristics depending on the coating degree, could be utilized in various ways in future studies.

Dual loaded nanostructured lipid carrier of nano-selenium and Etravirine as a potential anti-HIV therapy

There is a dire need for dual-long-acting therapy that could simultaneously target different stages of the HIV life cycle and providing a dual-prolonged strategy for improved anti-HIV therapy while reducing oxidative stress associated with the prolonged treatment. Thus, in the present work, nanostructured lipid carriers of Etravirine were developed and modified with nano-selenium. The dual-loaded nanocarrier system was fabricated using the double emulsion solvent evaporation method, further screened and optimized using the design of experiments methodology. The spherical core-shell type of a system was confirmed with an electron microscope and small-angle neutron scattering, while XPS confirmed the presence of selenium at the core-shell of the nanocarrier. In vitro assessment against HIV1 (R5 and X4 strains) infected TZM-bl cells exhibited higher efficacy for the dual-loaded nanocarrier system than the plain drug, which could be attributed to the synergistic effect of the nano-selenium. Confocal microscopy and flow cytometry results exhibited enhanced uptake in TZM-bl cells compared to plain drug. A significant increase of GSH, SOD, CAT was observed in animals administered with the dual-loaded nanocarrier system containing nano-selenium, suggesting the protective potential of the lipidic nanoparticle containing the nano-selenium. Improvement in the in vivo pharmacokinetic parameters was also observed, along with a higher accumulation of the dual-loaded nanocarrier in remote HIV reservoir organs like the brain, ovary, and lymph node. The results suggest the potential of a dual-loaded formulation for synergistically targeting the HIV1 infection while simultaneously improving the intracellular anti-oxidant balance for improving a prolonged anti-HIV therapy.

Multi-organ targeting of HIV-1 viral reservoirs with etravirine loaded nanostructured lipid carrier: An in-vivo proof of concept

The inadequate bioavailability and toxicity potential of antiretroviral therapy limit their effectiveness in the complete eradication of HIV from viral reservoirs. The penetration of these drugs into the brain is challenging because of the unfavorable physicochemical properties required to cross the membranes, limiting the transport of the drugs. Thus, in the current study, the authors report a nanocarrier-based drug delivery of a highly hydrophobic drug to overcome the existing limitations of the conventional therapies. An explicitly simple approach was used to overcome the limitations of existing anti-HIV therapies. The monophasic hot homogenized solution of lipid, drug, and solubilizer was diluted with the predetermined hot surfactant solution followed by the ultrasonication to generate the polydisperse nanoparticles with the size range of 50-1000 nm. The anti-HIV1 potential of nanostructured lipid carriers of Etravirine on HIV-infected cell lines showed efficacy with an appreciable increase in the therapeutic index as compared with the plain drug. Further, the results obtained from confocal microscopy along with flow cytometry exhibited efficient uptake of the nanocarrier loaded with coumarin-6 in cells. The pharmacokinetics of Etravirine nanostructured carriers was significantly better in all aspects compared to the plain drug solution, which could be attributed to molecular dispersion in the lipid matrix of the nanocarrier. A significant enhancement of Etravirine concentration of several-fold was also observed in the liver, ovary, lymph node, and brain, respectively, as compared to plain drug solution when assessed by biodistribution studies in rats. In conclusion, ETR-NLC systems could serve as a promising approach for simultaneous multi-site targeting and could provide therapeutic benefits for the efficient eradication of HIV/AIDS infections.

Development and Characterization of Saturated Fatty Acid-Engineered, Silica-Coated Lipid Vesicular System for Effective Oral Delivery of Alfa-Choriogonadotropin

The present study was designed to develop an efficient, safe, and patient-friendly dosage form, for oral delivery of alfa-choriogonadotropin, used in the treatment of female reproductive infertility. Silica-coated, saturated fatty acid (dipalmitoylphosphatidylcholine (DPPC))-engineered, nanolipidic vesicular (NLVs) system was developed for systemic delivery of therapeutic peptide, alfa-choriogonadotropin, through oral route. DPPC-based NLVs were formulated using the technique of thin-film hydration and were coated with silica to form a homogeneous surface silica shell. The formulated silica-coated NLVs were evaluated for physicochemical and physiologic stability under simulated conditions and were optimized based on physicochemical parameters like particle size, zeta potential, polydispersity index (PDI), entrapment efficiency, and in vitro release profile. Silica-coated, DPPC-based NLVs imparted physicochemical stability to entrapped alfa-choriogonadotropin against the biological environment prevailing in the human gastrointestinal tract (GIT). In vivo, subchronic animal toxicity studies were performed to assess the safety of the designed dosage form. Results of in vitro characterization and in vivo pharmacokinetic studies of fabricated formulation revealed that the silica-coated, DPPC-based NLV formulation was not only stable in human GIT but was also as efficacious as a marketed parenteral formulation for the systemic delivery of alfa-choriogonadotropin. In vivo toxicity studies revealed that silica-coated NLVs did not alter hematological and serum biochemical parameters. The histopathological studies also depicted no macroscopic changes in major organs; thus, the developed formulation was proven to be nontoxic and equally efficient as a marketed parenteral formulation for the delivery of alfa-choriogonadotropin with added benefits of possible self-medication, more patient acceptability, and no chances of infection.

Design, development and in-vitro/in-vivo evaluation of intranasally delivered Rivastigmine and N-Acetyl Cysteine loaded bifunctional niosomes for applications in combinative treatment of Alzheimer's disease

The present investigation explores the potential of novel dual drug-loaded niosomes for nasal delivery of Rivastigmine (RIV) and N-Acetyl Cysteine (NAC) to the brain. The dual niosomes showed a particle size of 162.4 nm and % entrapment efficiencies of 97.7% for RIV and 85.9% for NAC. The niosomes were statistically validated using Box-Behnken experimental design (BBD) with good significance. Ultrastructural and chemical characterization of the niosomes using various analytical techniques like Fourier Transform Infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), Transmission electron microscopy (TEM) showcased drug-excipient compatibility and robust stability of 6 months in a liquid state at 4-8 °C. The dual drug-loaded niosomes showed a sustained drug release pattern up to 2 days. Acetylcholinesterase (AChE) and DPPH (1, 1-diphenyl-2- picrylhydrazyl) enzyme inhibition assays showed a better combinative effect than the free drug solutions. A 2-day nasal permeation proved the effectiveness and biocompatibility of the niosomes. In-vivo pharmacokinetic and organ biodistribution studies revealed a better drug profile and greater distribution of the niosomes in the brain compared to other organs, thereby indicating a direct nose-to-brain delivery of the niosomes.

A Compressive Review about Taxol®: History and Future Challenges

Taxol^®, which is also known as paclitaxel, is a chemotherapeutic agent widely used to treat different cancers. Since the discovery of its antitumoral activity, Taxol^® has been used to treat over one million patients, making it one of the most widely employed antitumoral drugs. Taxol^® was the first microtubule targeting agent described in the literature, with its main mechanism of action consisting of the disruption of microtubule dynamics, thus inducing mitotic arrest and cell death. However, secondary mechanisms for achieving apoptosis have also been demonstrated. Despite its wide use, Taxol^® has certain disadvantages. The main challenges facing Taxol^® are the need to find an environmentally sustainable production method based on the use of microorganisms, increase its bioavailability without exerting adverse effects on the health of patients and minimize the resistance presented by a high percentage of cells treated with paclitaxel. This review details, in a succinct manner, the main aspects of this important drug, from its discovery to the present day. We highlight the main challenges that must be faced in the coming years, in order to increase the effectiveness of Taxol^® as an anticancer agent.

Recent Development of Copolymeric Nano-Drug Delivery System for Paclitaxel

Background:

Paclitaxel (PTX) has been clinically used for several years due to its good therapeutic effect against cancers. Its poor water-solubility, non-selectivity, high cytotoxicity to normal tissue and worse pharmacokinetic property limit its clinical application.

Objective:

To review the recent progress on the PTX delivery systems.

Methods:

In recent years, the copolymeric nano-drug delivery systems for PTX are broadly studied. It mainly includes micelles, nanoparticles, liposomes, complexes, prodrugs and hydrogels, etc. They were developed or further modified with target molecules to investigate the release behavior, targeting to tissues, pharmacokinetic property, anticancer activities and bio-safety of PTX. In the review, we will describe and discuss the recent progress on the nano-drug delivery system for PTX since 2011.

Results:

The water-solubility, selective delivery to cancers, tissue toxicity, controlled release and pharmacokinetic property of PTX are improved by its encapsulation into the nano-drug delivery systems. In addition, its activities against cancer are also comparable or high when compared with the commercial formulation.

Conclusion:

Encapsulating PTX into nano-drug carriers should be helpful to reduce its toxicity to human, keeping or enhancing its activity and improving its pharmacokinetic property.

Diagnostic and therapeutic evaluation of folate-targeted paclitaxel and vinorelbine encapsulating theranostic liposomes for non-small cell lung cancer

NSCLC is the most common type of lung cancer. However, non-specific contrast agents, radiopharmaceuticals, and treatment methods are insufficient in early diagnosis and eradication of all tumor tissue. Therefore, the formulation of a novel, targeted, specific theranostic agents possess critical importance. In our previous study, paclitaxel and vinorelbine encapsulating, Tc-99m radiolabeled, folate targeted, nanosized liposomes were formulated and found promising due to characterization properties, high cellular uptake, and cytotoxicity. In this study, in vivo therapeutic and diagnostic efficacy of liposomal formulations were tested by biodistribution study, evaluation of tumor growth inhibition, and histopathologic examination after in vitro assays on LLC1 cells. Both actively and passively targeted liposomal formulations exhibited high cellular uptake, and co-drug encapsulating liposomes showed a greater cytotoxicity profiles than free drug combination in LLC1 cells. By the results of biodistribution studies performed in NSCLC tumor-bearing C57BL/6 mice, the uptake of radiolabeled, actively folate targeted, co-drug encapsulating liposomal formulation was found to be higher in tumor tissue when compared to non-actively targeted one. Also, more effective treatment was achieved by using folate-targeted, co-drug encapsulating liposomal formulation when compared to free drugs combination according to changes in tumor size of mice. Furthermore, liposomal formulations showed lower toxicity compared to free drug combinations in the toxicity study considering body weight. Moreover, according to the histopathological study, folate targeted, co-drug encapsulating liposomes not only inhibited the tumor growth effectively but also restricted the lung metastasis entirely.

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.

Formulation Strategies for Folate-Targeted Liposomes and Their Biomedical Applications

The folate receptor (FR) is a tumor-associated antigen that can bind with folic acid (FA) and its conjugates with high affinity and ingests the bound molecules inside the cell via the endocytic mechanism. A wide variety of payloads can be delivered to FR-overexpressed cells using folate as the ligand, ranging from small drug molecules to large DNA-containing macromolecules. A broad range of folate attached liposomes have been proven to be highly effective as the targeted delivery system. For the rational design of folate-targeted liposomes, an intense conceptual understanding combining chemical and biomedical points of view is necessary because of the interdisciplinary nature of the field. The fabrication of the folate-conjugated liposomes basically involves the attachment of FA with phospholipids, cholesterol or peptides before liposomal formulation. The present review aims to provide detailed information about the design and fabrication of folate-conjugated liposomes using FA attached uncleavable/cleavable phospholipids, cholesterol or peptides. Advances in the area of folate-targeted liposomes and their biomedical applications have also been discussed.