Stealth anti-CD4 conjugated immunoliposomes with dual antiretroviral drugs--modern Trojan horses to combat HIV

CD4+ T cell-targeting immunoliposomes for treatment of latent HIV reservoir

Active targeting nano-delivery is a promising approach to enhance therapeutic efficacy and specificity to the target cells. Liposomes (LPs) have been widely studied for the active targeting delivery due to their low toxicity, biodegradability, biocompatibility, and feasibility of surface medication to provide the interactions with cell receptors. One of the strategies is to functionalize the surface of LPs with monoclonal antibodies (mAbs) to obtain immunoliposomes (imLPs) that recognize specific receptors on target cells. Among several target cells, CD4+ T cells are known for playing a pivotal role in controlling the immune system in several diseases, including cancers, inflammatory diseases, and viral infections, particularly HIV-1. Here, we demonstrate two methods for conjugating αCD4 mAb with imLPs for specific targeting of CD4+ T cells that can harbor viral genome and serve as a predominant latent HIV reservoir. LPs conjugated with αCD4 mAb via neutravidin-biotin linkage were used for selectively targeting CD4+ J-Lat 10.6 cells. We demonstrate, via flow cytometry, the importance of the conjugation step, mAb density, and the presence of polyethylene glycol (PEG) for effective drug delivery to CD4+ T cells. The cellular uptake of imLPs is substantially higher if the imLPs are functionalized with the pre-conjugated αCD4 mAb-neutravidin complex. Furthermore, imLPs loaded with HIV-1 latency reversing agent, suberoylanilide hydroxamic acid (SAHA), could reactivate the J-Lat 10.6 cells, suggesting that the αCD4-imLPs could be potentially used as a targeted drug delivery system for HIV-1 latency reactivation or other CD4-targeted immunotherapies.

Leveraging immunoliposomes as nanocarriers against SARS-CoV-2 and its emerging variants

The global COVID-19 pandemic arising from SARS-CoV-2 has impacted many lives, gaining interest worldwide ever since it was first identified in December 2019. Till 2023, 752 million cumulative cases and 6.8 million deaths were documented globally. COVID-19 has been rapidly evolving, affecting virus transmissibility and properties and contributing to increased disease severity. The Omicron is the most circulating variant of concern. Although success in its treatment has indicated progress in tackling the virus, limitations in delivering the current antiviral agents in battling emerging variants remain remarkable. With the latest advancements in nanotechnology for controlling infectious diseases, liposomes have the potential to counteract SARS-CoV-2 because of their ability to employ different targeting strategies, incorporating monoclonal antibodies for the active and passive targeting of infected patients. This review will present a concise summary of the possible strategies for utilizing immunoliposomes to improve current treatment against the occurrence of SARS-CoV-2 and its variants.

Review: Liposomes in the prophylaxis and treatment of infectious diseases

Infectious diseases remain as one of the major burdens among health communities as well as in the general public despite the advances in prevention and treatment. Although vaccination and vector eliminations have greatly prevented the transmission of these diseases, the effectiveness of these strategies is no longer guaranteed as new challenges such as drug resistance and toxicity as well as the missing effective therapeutics arise. Hence, the development of new tools to manage these challenges is anticipated, in which nano technology using liposomes as effective nanostructure is highly considered. In this review, we concentrate on the advantages of liposomes in the drug delivery system and the development of vaccine in the treatment of three major infectious diseases; tuberculosis (TB), malaria and HIV.

Nanodrugs Targeting T Cells in Tumor Therapy

In contrast to conventional anti-tumor agents, nano-carriers allow co-delivery of distinct drugs in a cell type-specific manner. So far, many nanodrug-based immunotherapeutic approaches aim to target and kill tumor cells directly or to address antigen presenting cells (APC) like dendritic cells (DC) in order to elicit tumor antigen-specific T cell responses. Regulatory T cells (Treg) constitute a major obstacle in tumor therapy by inducing a pro-tolerogenic state in APC and inhibiting T cell activation and T effector cell activity. This review aims to summarize nanodrug-based strategies that aim to address and reprogram Treg to overcome their immunomodulatory activity and to revert the exhaustive state of T effector cells. Further, we will also discuss nano-carrier-based approaches to introduce tumor antigen-specific chimeric antigen receptors (CAR) into T cells for CAR-T cell therapy which constitutes a complementary approach to DC-focused vaccination.

Craft of Co-encapsulation in Nanomedicine: A Struggle To Achieve Synergy through Reciprocity

Achieving synergism, often by combination therapy via codelivery of chemotherapeutic agents, remains the mainstay of treating multidrug-resistance cases in cancer and microbial strains. With a typical core-shell architecture and surface functionalization to ensure facilitated targeting of tissues, nanocarriers are emerging as a promising platform toward gaining such synergism. Co-encapsulation of disparate theranostic agents in nanocarriers-from chemotherapeutic molecules to imaging or photothermal modalities-can not only address the issue of protecting the labile drug payload from a hostile biochemical environment but may also ensure optimized drug release as a mainstay of synergistic effect. However, the fate of co-encapsulated molecules, influenced by temporospatial proximity, remains unpredictable and marred with events with deleterious impact on therapeutic efficacy, including molecular rearrangement, aggregation, and denaturation. Thus, more than just an art of confining multiple therapeutics into a 3D nanoscale space, a co-encapsulated nanocarrier, while aiming for synergism, should strive toward achieving a harmonious cohabitation of the encapsulated molecules that, despite proximity and opportunities for interaction, remain innocuous toward each other and ensure molecular integrity. This account will inspect the current progress in co-encapsulation in nanocarriers and distill out the key points toward accomplishing such synergism through reciprocity.

Targeted Delivery of Antifungal Liposomes to Rhizopus delemar

Mucormycosis (a.k.a. zygomycosis) is an often-life-threatening disease caused by fungi from the ancient fungal division Mucoromycota. Globally, there are nearly a million people with the disease. Rhizopus spp., and R. delemar (R. oryzae, R. arrhizus) in particular, are responsible for most of the diagnosed cases. Pulmonary, rhino-orbito-cerebral, and invasive mucormycosis are most effectively treated with amphotericin B (AmB) and particularly with liposomal formulations (e.g., AmBisome^®). However, even after antifungal therapy, there is still a 50% mortality rate. Hence, there is a critical need to improve therapeutics for mucormycosis. Targeting AmB-loaded liposomes (AmB-LLs) with the pathogen receptor Dectin-1 (DEC1-AmB-LLs) to the beta-glucans expressed on the surface of Aspergillus fumigatus and Candida albicans lowers the effective dose required to kill cells relative to untargeted AmB-LLs. Because Dectin-1 is an immune receptor for R. delemar infections and may bind it directly, we explored the Dectin-1-mediated delivery of liposomal AmB to R. delemar. DEC1-AmB-LLs bound 100- to 1000-fold more efficiently to the exopolysaccharide matrix of R. delemar germlings and mature hyphae relative to AmB-LLs. DEC1-AmB-LLs delivering sub-micromolar concentrations of AmB were an order of magnitude more efficient at inhibiting and/or killing R. delemar than AmB-LLs. Targeted antifungal drug-loaded liposomes have the potential to improve the treatment of mucormycosis.

DectiSomes: Glycan Targeting of Liposomal Drugs Improves the Treatment of Disseminated Candidiasis

Candida albicans causes life-threatening disseminated candidiasis. Individuals at greatest risk have weakened immune systems. An outer cell wall, exopolysaccharide matrix, and biofilm rich in oligoglucans and oligomannans help Candida spp. evade host defenses. Even after antifungal treatment, the 1-year mortality rate exceeds 25%. Undoubtedly, there is room to improve drug performance. The mammalian C-type lectin pathogen receptors Dectin-1 and Dectin-2 bind to fungal oligoglucans and oligomannans, respectively. We previously coated amphotericin B-loaded liposomes, AmB-LLs, pegylated analogs of AmBisome, with the ligand binding domains of these two Dectins. DectiSomes, DEC1-AmB-LLs and DEC2-AmB-LLs, showed two distinct patterns of binding to the exopolysaccharide matrix surrounding C. albicans hyphae grown in vitro. Here we showed that DectiSomes were preferentially associated with fungal colonies in the kidneys. In a neutropenic mouse model of candidiasis, DEC1-AmB-LLs and DEC2-AmB-LLs delivering only one dose of 0.2 mg/kg AmB reduced the kidney fungal burden several fold relative to AmB-LLs. DEC1-AmB-LLs and DEC2-AmB-LLs increased the percent of surviving mice 2.5-fold and 8.3-fold, respectively, relative to AmB-LLs. Dectin-2 targeting of anidulafungin loaded liposomes, DEC2-AFG-LLs, and of commercial AmBisome, DEC2-AmBisome, reduced fungal burden in the kidneys several fold over their untargeted counterparts. The data herein suggest that targeting of a variety of antifungal drugs to fungal glycans may achieve lower safer effective doses and improve drug efficacy against a variety of invasive fungal infections.

Nanomedicine based approaches for combating viral infections

Millions of people die each year from viral infections across the globe. There is an urgent need to overcome the existing gap and pitfalls of the current antiviral therapy which include increased dose and dosing frequency, bioavailability challenges, non-specificity, incidences of resistance and so on. These stumbling blocks could be effectively managed by the advent of nanomedicine. Current review emphasizes over an enhanced understanding of how different lipid, polymer and elemental based nanoformulations could be potentially and precisely used to bridle the said drawbacks in antiviral therapy. The dawn of nanotechnology meeting vaccine delivery, role of RNAi therapeutics in antiviral treatment regimen, various regulatory concerns towards clinical translation of nanomedicine along with current trends and implications including unexplored research avenues for advancing the current drug delivery have been discussed in detail.

CD4+ T cell-mimicking nanoparticles encapsulating DIABLO/SMAC mimetics broadly neutralize HIV-1 and selectively kill HIV-1-infected cells

HIV-1 is a major global health challenge. The development of an effective vaccine and a therapeutic cure are top priorities. The creation of vaccines that focus an antibody response toward a particular epitope of a protein has shown promise, but the genetic diversity of HIV-1 stymies this progress. Therapeutic strategies that provide effective and broad‐spectrum neutralization against HIV-1 infection are highly desirable.

Methods: We investigated the potential of nanoengineered CD4+ T cell membrane-coated nanoparticles (TNP) encapsulating the DIABLO/SMAC mimetics LCL-161 or AT-406 (also known as SM-406 or Debio 1143) to both neutralize HIV-1 and selectively kill HIV-1-infected resting CD4+ T cells and macrophages.

Results: DIABLO/SMAC mimetic-loaded TNP displayed outstanding neutralizing breadth and potency, and selectively kill HIV-1-infected cells via autophagy-dependent apoptosis while having no drug-induced off-target or cytotoxic effects on bystander cells. Genetic inhibition of early stages of autophagy abolishes this effect.

Conclusion: DIABLO/SMAC mimetic loaded TNP have the potential to be used as therapeutic agents to neutralize cell-free HIV-1 and to kill specifically HIV-1-infected cells as part of an HIV-1 cure strategy.

Challenges of Current Anticancer Treatment Approaches with Focus on Liposomal Drug Delivery Systems

According to a 2020 World Health Organization report (Globocan 2020), cancer was a leading cause of death worldwide, accounting for nearly 10 million deaths in 2020. The aim of anticancer therapy is to specifically inhibit the growth of cancer cells while sparing normal dividing cells. Conventional chemotherapy, radiotherapy and surgical treatments have often been plagued by the frequency and severity of side effects as well as severe patient discomfort. Cancer targeting by drug delivery systems, owing to their selective targeting, efficacy, biocompatibility and high drug payload, provides an attractive alternative treatment; however, there are technical, therapeutic, manufacturing and clinical barriers that limit their use. This article provides a brief review of the challenges of conventional anticancer therapies and anticancer drug targeting with a special focus on liposomal drug delivery systems.

Lipid Nanocarriers for Anti-HIV Therapeutics: A Focus on Physicochemical Properties and Biotechnological Advances

Since HIV was first identified, and in a relatively short period of time, AIDS has become one of the most devastating infectious diseases of the 21st century. Classical antiretroviral therapies were a major step forward in disease treatment options, significantly improving the survival rates of HIV-infected individuals. Even though these therapies have greatly improved HIV clinical outcomes, antiretrovirals (ARV) feature biopharmaceutic and pharmacokinetic problems such as poor aqueous solubility, short half-life, and poor penetration into HIV reservoir sites, which contribute to the suboptimal efficacy of these regimens. To overcome some of these issues, novel nanotechnology-based strategies for ARV delivery towards HIV viral reservoirs have been proposed. The current review is focused on the benefits of using lipid-based nanocarriers for tuning the physicochemical properties of ARV to overcome biological barriers upon administration. Furthermore, a correlation between these properties and the potential therapeutic outcomes has been established. Biotechnological advancements using lipid nanocarriers for RNA interference (RNAi) delivery for the treatment of HIV infections were also discussed.

An in-depth analysis of novel combinatorial drug therapy via nanocarriers against HIV/AIDS infection and their clinical perspectives: a systematic review

Introduction: Conventional antiretroviral therapy against HIV infections is threatening to become outdated due to the low chemical, physical, biological, and pharmacokinetic characteristics of therapeutic molecules, followed by the high chance of emergence of drug resistance. Considering the co-encapsulation of multi-infection agents in a single nanocarrier is emerging to offer various benefits such as synergistic action, improved therapeutic efficacy, reduced drug resistance development, patient compliance, and economical therapy.Areas covered: A systematic review of nano-based combinatorial drug therapy was performed using various databases including Scopus, PubMed, Google Scholar, and Science Direct between 2000 and 2020. The search set was screened as per the inclusion and exclusion criteria, followed by 46 scientific articles and seven clinical studies selected for in-depth analysis.Expert opinion: There has been an immense effort to analyze the mechanism of HIV infection to develop a promising therapeutic approach, although the aim of complete prevention has not been succeeded yet. The key finding is to overcome the challenges associated with conventional therapy by the combinatorial drug in a single nanoformulation, which holds great potential for impact in the management of HIV infection.

CD4+ T Cell-Mimicking Nanoparticles Broadly Neutralize HIV-1 and Suppress Viral Replication through Autophagy

HIV-1 is a major global health challenge. The development of an effective vaccine and/or a therapeutic cure is a top priority. The creation of vaccines that focus an antibody response toward a particular epitope of a protein has shown promise, but the genetic diversity of HIV-1 hinders this progress. Here we developed an approach using nanoengineered CD4⁺ T cell membrane-coated nanoparticles (TNP). Not only do TNP effectively neutralize all strains of HIV-1, but they also selectively bind to infected cells and decrease the release of HIV-1 particles through an autophagy-dependent mechanism with no drug-induced off-target or cytotoxic effects on bystander cells.

Therapeutic strategies that provide effective and broad‐spectrum neutralization against HIV-1 infection are highly desirable. Here, we investigate the potential of nanoengineered CD4⁺ T cell membrane-coated nanoparticles (TNP) to neutralize a broad range of HIV-1 strains. TNP displayed outstanding neutralizing breadth and potency; they neutralized all 125 HIV-1-pseudotyped viruses tested, including global subtypes/recombinant forms, and transmitted/founder viruses, with a geometric mean 80% inhibitory concentration (IC₈₀) of 819 μg ml⁻¹ (range, 72 to 8,570 μg ml⁻¹). TNP also selectively bound to and induced autophagy in HIV-1-infected CD4⁺ T cells and macrophages, while having no effect on uninfected cells. This TNP-mediated autophagy inhibited viral release and reduced cell-associated HIV-1 in a dose- and phospholipase D1-dependent manner. Genetic or pharmacological inhibition of autophagy ablated this effect. Thus, we can use TNP as therapeutic agents to neutralize cell-free HIV-1 and to target HIV-1 gp120-expressing cells to decrease the HIV-1 reservoir.

When liposomes met antibodies: Drug delivery and beyond

Drug encapsulated liposomes and monoclonal antibodies (Mabs) are two distinctively different classes of therapeutics, but both aim to become the ultimate "magic bullet". While PEGylated liposomes rely on the enhanced permeability and retention (EPR) effect for accumulation in solid tumor tissues, Mabs are designed to bind tightly to specific surface antigens on target cells to exert effector functions. Immunoliposome (IL) refers to the structural combination of liposomes and antibodies, whereas the antibodies are usually decorated on the liposome surface. ILs can therefore take advantage of interactions between antibodies and cancer cells for more efficient endocytosis and intracellular drug delivery. The antibody structure, affinity, density, as well as the liposome surface properties and drug to lipid ratios all contribute to the IL pharmacokinetic(PK) and pharmacodynamic(PD) behaviors. The optimal formulation parameters may vary for different target cells and tissues. Furthermore, besides the delivery of cytotoxic drugs to cancer cells, new ILs are being developed to interact with multiple target receptors, multiple target cells and trigger multiple therapeutic effects. We envision that the IL format can be a great platform for the molecular engineering of multi-valent, multi-specific interactions to achieve complex biological functions for therapeutic benefits, especially in the area of cancer immunotherapy.

The Potential of Long-Acting, Tissue-Targeted Synthetic Nanotherapy for Delivery of Antiviral Therapy Against HIV Infection

Oral administration of a combination of two or three antiretroviral drugs (cART) has transformed HIV from a life-threatening disease to a manageable infection. However, as the discontinuation of therapy leads to virus rebound in plasma within weeks, it is evident that, despite daily pill intake, the treatment is unable to clear the infection from the body. Furthermore, as cART drugs exhibit a much lower concentration in key HIV residual tissues, such as the brain and lymph nodes, there is a rationale for the development of drugs with enhanced tissue penetration. In addition, the treatment, with combinations of multiple different antiviral drugs that display different pharmacokinetic profiles, requires a strict dosing regimen to avoid the emergence of drug-resistant viral strains. An intriguing opportunity lies within the development of long-acting, synthetic scaffolds for delivering cART. These scaffolds can be designed with the goal to reduce the frequency of dosing and furthermore, hold the possibility of potential targeting to key HIV residual sites. Moreover, the synthesis of combinations of therapy as one molecule could unify the pharmacokinetic profiles of different antiviral drugs, thereby eliminating the consequences of sub-therapeutic concentrations. This review discusses the recent progress in the development of long-acting and tissue-targeted therapies against HIV for the delivery of direct antivirals, and examines how such developments fit in the context of exploring HIV cure strategies.

Enfuvirtide-Protoporphyrin IX Dual-Loaded Liposomes: In Vitro Evidence of Synergy against HIV-1 Entry into Cells

We have developed a nanocarrier consisting of large unilamellar vesicles (LUVs) for combined delivery of two human immunodeficiency virus type 1 (HIV-1) entry inhibitors, enfuvirtide (ENF) and protoporphyrin IX (PPIX). The intrinsic lipophilicity of ENF and PPIX, a fusion inhibitor and an attachment inhibitor, respectively, leads to their spontaneous incorporation into the lipid bilayer of the LUVs nanocarrier. Both entry inhibitors partition significantly toward LUVs composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and a 9:1 mixture of POPC:1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DPPE-PEG₂₀₀₀), representative of conventional and immune-evasive drug delivery formulations, respectively. These colocalize in the core of lipid membranes. Dual-loaded nanocarriers are monodispersed and retain the size distribution, thermotropic behavior, and surface charge of the unloaded form. Combination of the two entry inhibitors in the nanocarrier resulted in improved synergy against HIV-1 entry compared to combination in free form, strongly when immune-evasive formulations are used. We propose that the improved action of the entry inhibitors when loaded into the nanocarriers results from their slow release at the site of viral entry. Overall, liposomes remain largely unexplored platforms for combination of viral entry inhibitors, with potential for improvement of current antiretroviral therapy drug safety and application. Our work calls for a reappraisal of the potential of entry inhibitor combinations and delivery for clinical use in antiretroviral therapy.

Lipid-drug conjugates and associated carrier strategies for enhanced antiretroviral drug delivery

Mortality rate of patients infected with HIV-1 has been significantly reduced by using HAART. However, the virus to date has not been eradicated. Transmission of HIV-1 infection through sexual intercourse remains an ongoing challenge, with increased risk of infection occurring in women. Interestingly, ARV drugs can be chemically linked with lipids to produce lipid-drug conjugates (LDCs). This alters pharmacokinetic properties of ARV drugs and thereby resulting in improved effectiveness. Although LDCs can be administered without a delivery carrier, they are usually incorporated into suitable delivery systems such as lipid nanoparticles, polymeric nanoparticles, micelles, liposomes, emulsions, and carbon nanotubes. Given that LDCs have the potential to improve oral bioavailability, lipophilicity, toxicity, and drug targeting, it is of our great interest to review strategies of lipid-drug conjugation together with their delivery systems for enhanced antiretroviral efficacy.

Development of Dual Drug Eluting Cardiovascular Stent with Ultrathin Flexible Poly(l-lactide-co-caprolactone) Coating

The pleiotropic effects of the atorvastatin-fenofibrate combination can be effectively harnessed for site-specific therapy to minimize stent-related complications. The present study aims to utilize the pleiotropic effects of these two drugs entrapped in a uniform and defect-free coating of poly(l-lactide-co-caprolactone) (PLCL) on a stainless steel stent to overcome stent-associated limitations. The stent coating parameters were optimized using ultrasonic spray coating technique to achieve a thin, smooth, and defect-free dual drug-loaded polymer coating on the stent. The dual drug-loaded polymer coated stent was characterized for surface morphology, thickness and coating integrity. In vitro drug release kinetics of the fabricated stent reveals a sustained release of both drugs for more than 60 days. Significant reduction of thrombus formation and adhesion of lipopolysaccharide-stimulated macrophages on the dual drug containing polymer-coated stent indicates that the drug combination possesses antithrombotic and anti-inflammatory effects. The combination did not adversely influence endothelialization but significantly retarded smooth muscle cell proliferation indicating its potential to overcome restenosis. No bacterial biofilm formation was observed on the stent due to the antibacterial activity of atorvastatin. A rat subcutaneous model was used to evaluate the biocompatibility of the coated stent and compared with the commercial stent. MicroCT, scanning electron microscopy, and morphometric analyses revealed that the coated stents exhibited excellent histocompatibility with no inflammatory response as evidenced from the cytokine levels measured 28 days postimplantation. Our data demonstrates for the first time that the combination of atorvastatin and fenofibrate can be successfully employed in cardiovascular stents to overcome the current limitations of conventional drug-eluting stents.

The Promise of Long-Acting Antiretroviral Therapies: From Need to Manufacture

Antiretroviral therapy has transformed human immunodeficiency virus infections from certain death to a manageable chronic disease. Achieving strict adherence to drug regimens that limit toxicities and viral resistance is an achievable goal. Success is defined by halting viral transmission and by continuous viral restriction. A step towards improving treatment outcomes is in long-acting antiretrovirals. While early results remain encouraging there remain opportunities for improvement. These rest, in part, on the required large drug dosing volumes, local injection-site reactions, and frequency of injections. Thus, implantable devices and long-acting parenteral prodrugs have emerged which may provide more effective clinical outcomes. The recent successes in transforming native antiretrovirals into lipophilic and hydrophobic prodrugs stabilized into biocompatible surfactants can positively affect both. Formulating antiretroviral prodrugs demonstrates improvements in cell and tissue targeting, in drug-dosing intervals, and in the administered volumes of nanosuspensions. As such, the newer formulations also hold the potential to suppress viral loads beyond more conventional therapies with the ultimate goal of HIV-1 elimination when combined with other modalities.

Pharmacokinetic stability of macrocyclic peptide triazole HIV-1 inactivators alone and in liposomes

Previously, we reported the discovery of macrocyclic peptide triazoles (cPTs) that bind to HIV-1 Env gp120, inhibit virus cell infection with nanomolar potencies, and cause irreversible virion inactivation. Given the appealing virus-killing activity of cPTs and resistance to protease cleavage observed in vitro, we here investigated in vivo pharmacokinetics of the cPT AAR029b. AAR029b was investigated both alone and encapsulated in a PEGylated liposome formulation that was designed to slowly release inhibitor. Pharmacokinetic analysis in rats showed that the half-life of FITC-AAR029b was substantial both alone and liposome-encapsulated, 2.92 and 8.87 hours, respectively. Importantly, liposome-encapsulated FITC-AAR029b exhibited a 15-fold reduced clearance rate from serum compared with the free FITC-cPT. This work thus demonstrated both the in vivo stability of cPT alone and the extent of pharmacokinetic enhancement via liposome encapsulation. The results obtained open the way to further develop cPTs as long-acting HIV-1 inactivators against HIV-1 infection.

Dectin-1-Targeted Antifungal Liposomes Exhibit Enhanced Efficacy

Aspergillus species cause pulmonary invasive aspergillosis resulting in nearly 100,000 deaths each year. Patients at the greatest risk of developing life-threatening aspergillosis have weakened immune systems and/or various lung disorders. Patients are treated with antifungals such as amphotericin B (AmB), caspofungin acetate, or triazoles (itraconazole, voriconazole, etc.), but these antifungal agents have serious limitations due to lack of sufficient fungicidal effect and human toxicity. Liposomes with AmB intercalated into the lipid membrane (AmB-LLs; available commercially as AmBisome) have severalfold-reduced toxicity compared to that of detergent-solubilized drug. However, even with the current antifungal therapies, 1-year survival among patients is only 25 to 60%. Hence, there is a critical need for improved antifungal therapeutics. Dectin-1 is a mammalian innate immune receptor in the membrane of some leukocytes that binds as a dimer to beta-glucans found in fungal cell walls, signaling fungal infection. Using a novel protocol, we coated AmB-LLs with Dectin-1's beta-glucan binding domain to make DEC-AmB-LLs. DEC-AmB-LLs bound rapidly, efficiently, and with great strength to Aspergillus fumigatus and to Candida albicans and Cryptococcus neoformans, highly divergent fungal pathogens of global importance. In contrast, untargeted AmB-LLs and bovine serum albumin (BSA)-coated BSA-AmB-LLs showed 200-fold-lower affinity for fungal cells. DEC-AmB-LLs reduced the growth and viability of A. fumigatus an order of magnitude more efficiently than untargeted control liposomes delivering the same concentrations of AmB, in essence decreasing the effective dose of AmB. Future efforts will focus on examining pan-antifungal targeted liposomal drugs in animal models of disease.IMPORTANCE The fungus Aspergillus fumigatus causes pulmonary invasive aspergillosis resulting in nearly 100,000 deaths each year. Patients are often treated with antifungal drugs such as amphotericin B (AmB) loaded into liposomes (AmB-LLs), but all antifungal drugs, including AmB-LLs, have serious limitations due to human toxicity and insufficient fungal cell killing. Even with the best current therapies, 1-year survival among patients with invasive aspergillosis is only 25 to 60%. Hence, there is a critical need for improved antifungal therapeutics. Dectin-1 is a mammalian protein that binds to beta-glucan polysaccharides found in nearly all fungal cell walls. We coated AmB-LLs with Dectin-1 to make DEC-AmB-LLs. DEC-AmB-LLs bound strongly to fungal cells, while AmB-LLs had little affinity. DEC-AmB-LLs killed or inhibited A. fumigatus 10 times more efficiently than untargeted liposomes, decreasing the effective dose of AmB. Dectin-1-coated drug-loaded liposomes targeting fungal pathogens have the potential to greatly enhance antifungal therapeutics.

Insights on Oral Drug Delivery of Lipid Nanocarriers: a Win-Win Solution for Augmenting Bioavailability of Antiretroviral Drugs

The therapeutic functionality of innumerable antiretroviral drugs is supposedly obscured owing to their low metabolic stability in the gastrointestinal tract and poor solubilization property leading to poor oral bioavailability. Dictated by such needs, lipid-based formulations could be tailored using nanotechnology which would be instrumental in ameliorating the attributes of such drugs. The stupendous advantages which lipid nanocarriers offer including improved drug stability and peroral bioavailability coupled with sustained drug release profile and feasibility to incorporate wide array of drugs makes it a potential candidate for pharmaceutical formulations. Furthermore, they also impart targeted drug delivery thereby widening their arena for use. Therefore, the review will encompass the details pertaining to numerous lipid nanocarriers such as nanoemulsion, solid lipid nanoparticle, nanostructured lipid carriers, and so on. These nanocarriers bear the prospective of improving the mucosal adhesion property of the drugs which ultimately upgrades its pharmacokinetic profile. The biodegradable and physiological nature of the lipid excipients used in the formulation is the key parameter and advocates for their safe use. Nevertheless, these lipid-based nanocarriers are amenable to alterations which could be rightly achieved by changing the excipients used or by modifying the process parameters. Thus, the review will systematically envisage the impending benefits and future perspectives of different lipid nanocarriers used in oral delivery of antiretroviral drugs.

Combination drug therapy via nanocarriers against infectious diseases

Current drug therapy against infections is threatening to become obsolete due to the poor physical, chemical, biological and pharmacokinetic properties of drugs, followed by high risk of acquiring resistance. Taking into account the significant benefits of nanotechnology, nano-based delivery of anti-infectious agents is emerging as a potential approach to combat several lethal infections. Co-delivery of multiple anti-infectious agents in a single nano-based system is beginning to show significant advantages over mono-therapy, such as synergism, enhanced anti-microbial activity, broad anti-microbial spectrum, reduced resistance development, and improved and cost-effective treatment. The current review provides a detailed update on the status of various lipid and polymer based nano-systems used to co-deliver multiple anti-infectious agents against bacterial, HIV and malarial infections. It also identifies current key challenges and suggests strategies to overcome them, thus guiding formulation scientists to further optimize nano-based co-drug delivery as an approach to fight infections effectively.

Skin cancer treatment effectiveness is improved by iontophoresis of EGFR-targeted liposomes containing 5-FU compared with subcutaneous injection

Squamous cell carcinoma (SCC) is a malignant tumor in which epidermal growth factor receptor (EGFR) overexpression is associated with poor prognosis and malignancy. For SCC treatment, cetuximab, an anti-EGFR antibody, is administered in combination with a chemotherapeutic drug for improved efficacy. In this work, an EGFR-targeted immunoliposome loaded with 5-fluorouracil (5- FU) was developed to allow co-administration of the antibody and the chemotherapeutic agent and selective delivery to SCC cells. Topically applied iontophoresis and subcutaneous injections of the 5-FU-loaded immunoliposomes were employed in an SCC xenograft animal model to evaluate the influence of the administration route on therapeutic efficacy. In vitro, cellular uptake of cetuximab-immunoliposomes by EGFR-positive SCC cells was 3.5-fold greater than the uptake of control liposomes. Skin penetration studies showed that iontophoresis of immunoliposomes doubled the 5-FU penetration into the viable epidermis compared with the same treatment with control liposomes. In vivo, subcutaneous injection of immunoliposomes reduced tumor volume by >60% compared with the negative control and approximately 50% compared with the 5-FU solution and control liposome treatments. Interestingly, topical administration via iontophoresis improved tumor reduction by almost 2-fold compared with subcutaneous administration of 5-FU solution and control liposomes but was equally effective for the immunoliposome treatment. However, histological analysis showed that iontophoresis of immunoliposomes was more effective than subcutaneous injection in reducing cell proliferation, resulting in cells with less aggressive characteristics. In conclusion, topical administration of immunoliposomes containing 5-FU using iontophoresis is a promising strategy for SCC treatment.

Recent developments of nanotherapeutics for targeted and long-acting, combination HIV chemotherapy

Combination antiretroviral therapy (cART) given orally has transformed HIV from a terminal illness to a manageable chronic disease. Yet despite the recent development of newer and more potent drugs for cART and suppression of virus in blood to undetectable levels, residual virus remains in tissues. Upon stopping cART, virus rebounds and progresses to AIDS. Current oral cART regimens have several drawbacks including (1) challenges in patient adherence due to pill fatigue or side-effects, (2) the requirement of life-long daily drug intake, and (3) limited penetration and retention in cells within lymph nodes. Appropriately designed injectable nano-drug combinations that are long-acting and retained in HIV susceptible cells within lymph nodes may address these challenges. While a number of nanomaterials have been investigated for delivery of HIV drugs and drug combinations, key challenges involve developing and scaling delivery systems that provide a drug combination targeted to HIV host cells and tissues where residual virus persists. With validation of the drug-insufficiency hypothesis in lymph nodes, progress has been made in the development of drug combination nanoparticles that are long-acting and targeted to lymph nodes and cells. Unique drug combination nanoparticles (DcNPs) composed of three HIV drugs-lopinavir, ritonavir, and tenofovir-have been shown to provide enhanced drug levels in lymph nodes; and elevated drug-combination levels in HIV-host cells in the blood and plasma for two weeks. This review summarizes the progress in the development of nanoparticle-based drug delivery systems for HIV therapy. It discusses how injectable nanocarriers may be designed to enable delivery of drug combinations that are long-lasting and target-selective in physiological contexts (in vivo) to provide safe and effective use. Consistent drug combination exposure in the sites of residual HIV in tissues and cells may overcome drug insufficiency observed in patients on oral cART.

Nano-ART and NeuroAIDS

Human immunodeficiency virus (HIV) is a neurotropic virus that enters the central nervous system (CNS) early in the course of infection. Although highly active antiretroviral therapy (HAART) has resulted in remarkable decline in the morbidity and mortality in AIDS patients, controlling HIV infections still remains a global health priority. HIV access to the CNS serves as the natural viral preserve because most antiretroviral (ARV) drugs possess inadequate or zero delivery across the brain barriers. The structure of the blood-brain barrier (BBB), the presence of efflux pumps, and the expression of metabolic enzymes pose hurdles for ARV drug-brain entry. Thus, development of target-specific, effective, safe, and controllable drug delivery approach is an important health priority for global elimination of AIDS progression. Nanoformulations can circumvent the BBB to improve CNS-directed drug delivery by affecting such pumps and enzymes. Alternatively, they can be optimized to affect their size, shape, and protein and lipid coatings to facilitate drug uptake, release, and ingress across the barrier. Improved drug delivery to the CNS would affect pharmacokinetic and drug biodistribution properties. This review focuses on how nanotechnology can serve to improve the delivery of antiretroviral medicines, termed NanoART, across the BBB and affect the biodistribution and clinical benefit for NeuroAIDS.

Immunoliposomes: A review on functionalization strategies and targets for drug delivery

Nanoparticles, especially liposomes, have gained prominence in the field of drug delivery for the treatment of human diseases, particularly cancer; they provide several advantages, including controlled drug release, protection of the drug against degradation, improved pharmacokinetics, long circulation, and passive targeting to tumors and inflammatory sites due to the enhanced permeability and retention effect. The functionalization of liposomes with monoclonal antibodies or antibody fragments to generate immunoliposomes has emerged as a promising strategy for targeted delivery to and uptake by cells overexpressing the antigens to these antibodies, with a consequent reduction in side effects. In this review, we address functionalization strategies for the non-covalent and covalent attachment of monoclonal antibodies and their fragments to liposomal surfaces. The main reaction occurs between the sulfhydryl groups of thiolated antibodies and maleimide-containing liposomes. Furthermore, we explore the main targeting possibilities with these ligands for the treatment of a variety of pathologies, including HER2- and EGFR-positive cancers, inflammatory and cardiovascular diseases, infectious diseases, and autoimmune and neurodegenerative diseases, which have not previously been reviewed together. Overall, many studies have shown selective delivery of immunoliposomes to target cells, with promising in vivo results, particularly for cancer treatment. Although clinical trials have been conducted, immunoliposomes have not yet received clinical approval. However, immunoliposomes are promising formulations that are expected to become available for therapeutic use after clinical trials prove their safety and efficacy, and after scaling issues are resolved.

Long-acting slow effective release antiretroviral therapy

INTRODUCTION

Advances in long-acting antiretroviral therapy (ART) can revolutionize current HIV/AIDS treatments. We coined the term 'long-acting slow effective release ART' (LASER ART) to highlight the required formulation properties of slow drug dissolution, poor water-solubility, bioavailability, little-to-no off-target toxicities and improved regimen adherence. Drug carrier technologies characterized by high antiretroviral drug (ARV) payloads in a single carrier improve the pharmacokinetic and pharmacodynamic profiles. The surface modifications of ARV carriers target monocyte-macrophages and facilitate drug transport across physiological barriers and to virus-susceptible CD4 + T cells. Areas covered: The review highlights developments of reservoir-targeted LASER ART for improved therapeutic outcomes. Such nanoART delivery platforms include decorated multifunctional nano- and micro-particles, prodrugs and polymer conjugates. Therapeutic strategies such as gene-editing technologies boost ART effectiveness. Expert opinion: The persistence of HIV-1 in lymphoid, gut and nervous system reservoirs poses a challenge to viral eradication. Emerging slow-release drug carriers can target intracellular pathogens, activate antiviral immunity, promote genome editing, sustain drug depots and combine therapeutics with image contrast agents, and can meet unmet clinical needs for HIV-infected patients. Such efforts will bring the medicines to reservoir sites and accelerate viral clearance.

Lipid raft-like liposomes used for targeted delivery of a chimeric entry-inhibitor peptide with anti-HIV-1 activity

The work reports the design and synthesis of a chimeric peptide that is composed of the peptide sequences of two entry inhibitors which target different sites of HIV-1 gp41. The chimeric peptide offers the advantage of targeting two gp41 regions simultaneously: the fusion peptide and the loop both of which are membrane active and participate in the membrane fusion process. We therefore use lipid raft-like liposomes as a tool to specifically direct the chimeric inhibitor peptide to the membrane domains where the HIV-1 envelope protein is located. Moreover, the liposomes that mimic the viral membrane composition protect the chimeric peptide against proteolytic digestion thereby increasing the stability of the peptide. The described liposome preparations are suitable nanosystems for managing hydrophobic entry-inhibitor peptides as putative therapeutics.

Epidermal growth factor receptor-targeted immunoliposomes for delivery of celecoxib to cancer cells

Cyclooxygenase-2 (COX-2) is highly expressed in many different cancers. Therefore, the inhibition of the COX-2 pathway by a selective COX-2 inhibitor, celecoxib (CLX), may be an alternative strategy for cancer prevention and therapy. Liposomal drug delivery systems can be used to increase the therapeutic efficacy of CLX while minimizing its side effects. Previous studies have reported the encapsulation of CLX within the non-targeted long circulating liposomes and functional effect of these formulations against colorectal cancer cell lines. However, the selectivity and internalization of CLX-loaded liposomes can further be improved by grafting targeting ligands on their surface. Cetuximab (anti-epidermal growth factor receptor - EGFR - monoclonal antibody) is a promising targeting ligand since EGFR is highly expressed in a wide range of solid tumors. The aim of this study was to develop EGFR-targeted immunoliposomes for enhancing the delivery of CLX to cancer cells and to evaluate the functional effects of these liposomes in cancer cell lines. EGFR-targeted ILs, having an average size of 120nm, could encapsulate 40% of the CLX, while providing a sustained drug release profile. Cell association studies have also shown that the immunoliposome uptake was higher in EGFR-overexpressing cells compared to the non-targeted liposomes. In addition, the CLX-loaded-anti-EGFR immunoliposomes were significantly more toxic compared to the non-targeted ones in cancer cells with EGFR-overexpression but not in the cells with low EGFR expression, regardless of their COX-2 expression status. Thus, selective targeting of CLX with anti-EGFR immunoliposomes appears to be a promising strategy for therapy of tumors that overexpress EGFR.